IPAC2021 - Table of Session: TUPAB (Tuesday Poster Session)

Paper	Title	Page
TUPAB001	DAΦNE Commissioning for SIDDHARTA-2 Experiment	1322
	C. Milardi, D. Alesini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, A. D’Uffizi, A. De Santis, C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, G. Franzini, A. Gallo, S. Incremona, A. Michelotti, L. Pellegrino, L. Piersanti, R. Ricci, U. Rotundo, L. Sabbatini, A. Stecchi, A. Stella, A. Vannozzi, M. Zobov INFN/LNF, Frascati, Italy J. Chavanne, G. Le Bec, P. Raimondi ESRF, Grenoble, France
	DAΦNE, the Frascati lepton collider, has completed the preparatory phase in order to deliver luminosity to the SIDDHARTA-2 detector. DAΦNE colliding rings rely on a new interaction region, which implements the well-established Crab-Waist collision scheme, and includes a low-beta section equipped with newly designed permanent magnet quadrupoles, and vacuum components. Diagnostics tools have been improved, especially the ones used to keep under control the beam-beam interaction. The horizontal feedback in the positron ring has been potentiated in order to achieve a higher positron current. Luminosity diagnostics have been also updated so to be compatible with the new detector design. The commissioning was initially focused on recovering the optimal dynamical vacuum conditions, outlining alignment errors, and optimizing ring optics. For this reason, a detuned optics, featured by relaxed low-b condition at the interaction point and Crab-Waist Sestupoles off, has been applied. In a second stage a low-b optics has been implemented to test collisions with a preliminary setup of the experiment detector. Machine preparation and the first luminosity results are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB001
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021
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TUPAB002	Round Colliding Beams: Successful Operation Experience	1326
	D.B. Shwartz, O.V. Belikov, D.E. Berkaev, D.B. Burenkov, V.S. Denisov, A.S. Kasaev, A.N. Kirpotin, S.A. Kladov, I. Koop, A.A. Krasnov, A.V. Kupurzhanov, G.Y. Kurkin, M.A. Lyalin, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, Yu.A. Rogovsky, A.M. Semenov, A.I. Senchenko, L.E. Serdakov, D.N. Shatilov, P.Yu. Shatunov, Y.M. Shatunov, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov BINP SB RAS, Novosibirsk, Russia S.A. Kladov, I. Koop, A.A. Krasnov, M.A. Lyalin, E. Perevedentsev, Yu.A. Rogovsky, Y.M. Shatunov, D.B. Shwartz NSU, Novosibirsk, Russia
	VEPP-2000 electron-positron collider operating in the beam energy range of 150-1000 MeV is the only machine originally designed for and successfully exploiting Round Beams Concept. After injection chain upgrade including link to the new BINP injection complex VEPP-2000 proceeded with data taking since 2017 with luminosity limited only by beam-beam effects. At the low energies (300-600 MeV/beam) the novel technique of effective emittance controlled increase by weak coherent beam shaking allowed to suppress the limiting flip-flop effect and resulted in additional luminosity gain factor of 4. The averaged delivered luminosity at the omega-meson production energy (2391 MeV) achieved L = 210³¹cm^-2s⁻¹/IP. At the top energies above nucleon-antinucleon production threshold the stable operation with luminosity of L = 5*10³¹cm^-2s⁻¹/IP resulted in high average data taking rate of 2 pb^-1/day in 2020.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB002
About •	paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021
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TUPAB003	Final Focus Solenoids Beam-Based Positioning Tests	1330
	D.B. Shwartz BINP SB RAS, Novosibirsk, Russia D.B. Shwartz NSU, Novosibirsk, Russia
	The final focusing at the VEPP-2000 electron-positron collider is done by 13 T superconducting solenoids. The misalignment of solenoids not only provides closed orbit distortions but also harmful for dynamic aperture reduction due to strong nonlinear fringe fields. The final beam-based alignment of solenoids was foreseen but turned out to be not a trivial procedure. Here we present the test study of solenoids positioning reconstruction procedure based on circulating beam orbit responses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB003
About •	paper received ※ 22 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021
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TUPAB004	Comparison of Accelerator Codes for Simulation of Lepton Colliders	1334
	L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland
	This paper compares simulation results obtained with SAD, MAD-X and the PTC implementation in MADX for the design studies of the FCC-ee. On-momentum and off-momentum optics are explored for the various programs. Particle tracking with and without synchrotron radiation are used to compare amplitude detuning and emittance. Finally, this paper outlines how well-established SAD features such as tapering have recently been integrated into MADX.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB004
About •	paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 26 August 2021
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TUPAB005	Emittance Estimates for the Future Circular Collider	1338
	L. van Riesen-Haupt, T.K. Charles, R. Tomás García, F. Zimmermann CERN, Meyrin, Switzerland T.K. Charles The University of Liverpool, Liverpool, United Kingdom
	The alignment strategy of the FCC-ee has a large impact on its luminosity. Larger alignment tolerances result in increased coupling and a subsequently higher vertical emittance. At the same time, tighter alignment tolerances around the 100 km ring are a major cost driver. This paper applies analytical emittance estimate methods to the FCC-ee and compares their predictions to data from simulations with different alignment tolerances. These methods can be used to help understand the impact of misalignments of certain magnet groups and to come up with an efficient alignment strategy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB005
About •	paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021
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TUPAB006	The Impact of Beam Position Monitor Tilts on Coupling Measurements	1342
	L. van Riesen-Haupt, R. Tomás García CERN, Meyrin, Switzerland
	The measurement and correction of coupling resonance driving terms is a key tool for improving the performance of synchrotrons. These terms are measured by exciting the beam and observing the subsequent motion in the horizontal and vertical planes through beam position monitors. This paper outlines the impact of tilt errors in these monitors to the distortion of the amount of coupling measured between the planes and how the computation of the resonance driving terms is affected by these tilts. It also attempts to use these results for mimicking tilt errors in simulations and discusses how discrepancies in measured resonance driving terms could be used to estimate the tilt errors that cause them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB006
About •	paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 12 August 2021
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TUPAB007	A Correction Scheme for the Magnet Imperfection on the CEPC Collider Ring	1346
	B. Wang, Y. Wangpresenter, Y. Wei, C.H. Yu, Y. Zhang IHEP, Beijing, People’s Republic of China
	This paper describes the error correction scheme for the CEPC CDR lattice in Higgs mode, which has a small beta function at the interaction point. The low emittance optics has an enhanced sensitivity to the magnet misalignments and field errors, especially for the final focus quadrupole misalignment. The magnet imperfection will cause the closed orbit distortion and optics distortion. The correction scheme for these magnet imperfections includes the closed orbit correction, the dispersion correction, the beta function correction and the betatron coupling correction. The resulting performance and the dynamic aperture for the corrected lattice are studied.
	Poster TUPAB007 [1.075 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB007
About •	paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021
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TUPAB008	Progress of the First-Turn Commissioning Simulations for HEPS	1349
	B. Wang, Z. Duan, D. Ji, Y. Jiaopresenter, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is 6 GeV, kilometer-scale, 4th generation storage ring light source. The lattice has an ultralow emittance and strong focusing such that the beam dynamics is very sensitive to the magnet misalignments and other error sources. Getting the first turn and establishing the closed orbit is essential for accelerator commissioning. This paper describes a simulation algorithm for achieving the first turn commission based on the latest HEPS storage ring lattice. We developed a new accelerator toolbox (AT)-based program for automatic optimizing the first turn commissioning. The algorithm and simulation results will be presented in this paper.
	Poster TUPAB008 [0.646 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB008
About •	paper received ※ 14 May 2021 paper accepted ※ 11 June 2021 issue date ※ 28 August 2021
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TUPAB009	SuperKEKB Optics Measurements Using Turn-by-Turn Beam Position Data	1352
	J. Keintzel, R. Tomás García CERN, Geneva, Switzerland H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, M. Tobiyama, R.J. Yang KEK, Ibaraki, Japan
	SuperKEKB, an asymmetric electron-positron collider, has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} using crab-waist collision scheme. In order to reach the design value of 6×10³⁵ \si{cm^-2s^-1} a vertical beta function at the interaction point of §I{0.3}{mm} is required, demanding unprecedented optics control. Turn-by-turn beam position data could enable fast optics measurements for rapid identification of unexpected error sources. Experiments exploring various data acquisition techniques at different squeezing steps during commissioning are presented and compared to results obtained from closed orbit distortion.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB009
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021
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TUPAB010	Impact of Bunch Current on Optics Measurements in SuperKEKB	1356
	J. Keintzel, R. Tomás García, F. Zimmermann CERN, Geneva, Switzerland T. Ishibashi, H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, S. Terui, M. Tobiyama, R.J. Yang, D. Zhou KEK, Ibaraki, Japan
	SuperKEKB has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} and aims at reaching a target luminosity of about 6 × 10³⁵ \si{cm^-2s^-1}. To accomplish this goal it is planned to increase beam currents up to §I{3.6}{A} and §I{2.6}{A} for the positron and the electron ring, respectively. Increasing the beam currents and, in particular, the number of leptons per bunch, can impact the optics parameters obtained by turn-by-turn measurements, such as the betatron tune or phase advance. Optics measurements performed at various bunch currents can give first indications of possible intensity dependent effects. In this paper, the effect of varying bunch current on optics measurements at SuperKEKB is explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB010
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 30 August 2021
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TUPAB011	Momentum Compaction Factor Measurements in the Large Hadron Collider	1360
	J. Keintzel, L. Malina, R. Tomás García CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) at CERN and its planned luminosity upgrade, the High Luminosity LHC (HL-LHC) demand well-controlled on- and off-momentum optics. Optics measurements are performed by analysing Turn-by-Turn (TbT) data of excited beams. Different techniques to measure the momentum compaction factor from these data are explored, taking into account the possibility to combine them with RF-voltage scans in future experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB011
About •	paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021
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TUPAB013	A CLIC Dual Beam Delivery System for Two Interaction Regions	1364
	V. Cilento, R. Tomás García CERN, Geneva, Switzerland A. Faus-Golfe Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	The Compact Linear Collider (CLIC) could provide e⁺e⁻ collisions in two detectors simultaneously possibly at a repetition frequency twice the design value. In this paper, a novel dual Beam Delivery System (BDS) design is presented including optics designs and the evaluation of luminosity performance with synchrotron radiation (SR) and solenoid effects for both energy stages of CLIC, 380 GeV and 3 TeV. In order to develop the novel optics design, parameters such as the longitudinal and the transverse detector separations were optimized. The luminosity performance of the novel CLIC scheme was evaluated by comparing the different BDS designs for both energy stages of CLIC. The dual CLIC BDS design provides a good luminosity and proves to be a viable candidate for future linear collider projects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB013
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021
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TUPAB015	Beam Loading Compensation of APS Cavity with Off-Crest Acceleration in ILC e-Driven Positron Source	1368
	M. Kuriki, S. Konno, H. Nagoshi HU/AdSM, Higashi-Hiroshima, Japan T. Omori, J. Urakawa, K. Yokoya KEK, Ibaraki, Japan T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	In E-Driven positron source of ILC, the generated positron is captured by RF accelerator by APS cavity. The positron is initially placed at the deceleration phase and gradually slipped down to acceleration phase. Because the beam-loading is expected to be more than 1A with a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation is controlling the timing, but it doesn’t work in off-crest case. In this manuscript, we discuss the compensation with the phase and amplitude modulation on the input RF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB015
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021
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TUPAB016	ESS RFQ: Installation and Tuning at Lund	1372
	P. Hamel, D. Chirpaz-Cerbat, M. Desmons, A.C. France, O. Piquet CEA-IRFU, Gif-sur-Yvette, France A. Dubois, Y. Le Noa CEA-DRF-IRFU, France
	The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019. It has been provided by CEA, IRFU, Saclay/France. It consists of five sections with a total length of 4.6 m and accelerates the 70 mA proton beam from 75 keV up to 3.6 MeV. It will be fed with 900 kW peak power through two coaxial loop couplers. The installation process (alignment, vacuum test), as well as the tuning process based on bead-pull measurements, is presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB016
About •	paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 14 August 2021
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TUPAB017	Study of Conduction-Cooled Superconducting Quadrupole Magnets Combined with Dipole Correctors for the ILC Main Linac	1375
	Y. Arimoto, S. Michizono, Y. Morikawa, N. Ohuchi, T. Oki, H. Shimizu, K. Umemori, X. Wang, A. Yamamoto, Y. Yamamoto, Z.G. Zong KEK, Ibaraki, Japan V.S. Kashikhin Fermilab, Batavia, Illinois, USA
	A superconducting rf (SRF) cryomodule for International Linear Collider(ILC) Main Linac equips focus/steering magnets. The magnets are "superferric" magnets with four superconducting (SC) race track coils conductively cooled from the cryomodule LHe supply pipe. The quadrupole field gradient and dipole field are 40 T/m and 0.1 T, respectively. The magnet length and iron-pole radius are 1 m and 0.045 m, respectively. It is known that dark current is generated at SRF cavities and accelerated through the following linac string. The dark current reaches and heats the SC magnets. It is estimated that the power deposition in the magnet may reach more than a few watts and temperature of the SC coils may locally reach to critical temperature of NbTi. It is important to make the magnet not reach quench with sufficient conduction cooling. We aim to realize the SC magnet which can stably operate under such condition. We plan to develop test coils made of three types of SC materials, NbTi, Nb₃Sn, and MgB₂ and study thermal characteristics and stability . We will develop a short model magnet, based on the test coil results. Here, we will present the magnet design study and the R&D plan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB017
About •	paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021
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TUPAB019	A High-Resolution, Low-Latency, Bunch-by-Bunch Feedback System for Nano-Beam Stabilization	1378
	R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom D.R. Bett CERN, Geneva, Switzerland N. Blaskovic Kraljevic ESS, Lund, Sweden G.B. Christian DLS, Oxfordshire, United Kingdom
	A low-latency, bunch-by-bunch feedback system employing high-resolution cavity Beam Position Monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at the High Energy Accelerator Research Organization (KEK), Japan. The feedback system was designed to demonstrate nanometer-level vertical stabilization at the focal point of the ATF2 and can be operated using either a single BPM to provide local beam stabilization, or by using two BPMs to stabilize the beam at an intermediate location. The feedback correction is implemented using a stripline kicker and the feedback calculations are performed on a digital board constructed around a Field Programmable Gate Array (FPGA). The feedback performance was tested with trains of two bunches, separated by 280ns, at a charge of ~1nC, where the vertical offset of the first bunch was measured and used to calculate the correction to be applied to the second bunch. The BPMs have been demonstrated to achieve an operational resolution of ~20nm. With the application of single-BPM and two-BPM feedback, beam stabilization of below 50nm and 41nm respectively has been achieved with a latency of 232ns.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB019
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021
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TUPAB020	A Sub-Micron Resolution, Bunch-by-Bunch Beam Trajectory Feedback System and Its Application to Reducing Wakefield Effects in Single-Pass Beamlines	1382
	D.R. Bett, P. Burrows, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom D.R. Bett CERN, Geneva, Switzerland K. Kubo, T. Okugi, N. Terunuma KEK, Ibaraki, Japan
	A high-precision intra-bunch-train beam orbit feedback correction system has been developed and tested at the KEK Accelerator Test Facility, ATF2. The system uses the vertical position of the bunch measured at two beam position monitors to calculate a pair of kicks which are applied to the next bunch using two upstream kickers, thereby correcting both the vertical position and trajectory angle. Using trains of two electron bunches separated in time by 187.6ns, the system was optimised so as to stabilize the beam offset at the feedback BPMs to better than 350nm, yielding a local trajectory angle correction to within 250nrad. The quality of the correction was verified using three downstream witness BPMs and the results were found to be in agreement with the predictions of a linear lattice model used to propagate the beam trajectory from the feedback region. This same model predicts a corrected be am jitter of c.1nm at the focal point of the accelerator. Measurements with a beam size monitor at this location demonstrate that reducing the trajectory jitter of the beam by a factor of 4 also reduces the increase in the measured beam size as a function of beam charge by a factor of ~1.6.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB020
About •	paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 11 August 2021
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TUPAB023	Design Considerations of a High Intensity Booster for PETRA IV	1386
	H.C. Chao, I.V. Agapov, S.A. Antipovpresenter DESY, Hamburg, Germany
	A 6 GeV booster lattice with a high intensity capacity for the PETRA IV project is presented. Firstly the requirements and constraints are articulated. Due to the geometric constraints the ring will be installed in racks mounted on ceilings. Then following some design strategies of reaching high intensity limit, a lattice is designed and presented. The topics covering the linear optics, nonlinear dynamics, orbit correction, orbit bump, and some instability studies are investigated.
	Poster TUPAB023 [0.975 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB023
About •	paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 12 August 2021
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TUPAB024	Lattice Options Comparison for a DLSR Injector	1390
	H.C. Chao, I.V. Agapov, S.A. Antipovpresenter DESY, Hamburg, Germany
	DESY IV, as a part of the injector chain, must have lower emittance for PETRA IV injection. Depending on the scenarios of the injector, two lattice options for DESY IV are presented. They are designed for different purposes. The first option comes with a high momentum compaction factor with acceptable emittance. It is designed to be a full intensity booster. The other option is with low emittance dedicated to be an accumulator at high energies. The general beam dynamics properties are simulated and discussed. Their strengths and weaknesses are compared.
	Poster TUPAB024 [0.751 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB024
About •	paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021
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TUPAB026	Application of Plasma Lenses as Optical Matching Device for Positron Sources at Linear Colliders	1394
	M. Formela, N. Hamann, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany K. Flöttmann, G.A. Moortgat-Pick DESY, Hamburg, Germany S. Riemann DESY Zeuthen, Zeuthen, Germany
	Funding: Quantum Universe In the baseline design of the International Linear Collider (ILC) an undulator-based positron source is foreseen. The proposed luminosity of the recently chosen first energy stage with √{s}=250 GeV requires an improvement by a factor of 2500 to the world’s first linear collider, the past SLC experiment. This ambitious luminosity goal can only be achieved, if all technological boundaries are being pushed. One such area is the captured positron number, which is primarily determined in the capture section within the positron source and specifically by its optical matching device. It is responsible for transforming the phase-space of the outgoing particles produced in the target for the succeeding accelerator sections. The plasma lens is a new candidate for this task. It being an especially adequate method due its magnetic field being azimuthal. Optimizing an idealised tapered active plasma lens for the ILC led us to a design with improved captured positron yield, outperforming ILC’s currently proposed quarter wave transformer by approximately 50%. The captured yield also proved to be stable within ±1.5% for deviations in design parameters of ±10%.
	Poster TUPAB026 [0.293 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB026
About •	paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 24 August 2021
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TUPAB027	Review of Accelerator Limitations and Routes to Ultimate Beams	1397
	F. Zimmermann CERN, Geneva, Switzerland R.W. Aßmann DESY, Hamburg, Germany M. Bai, G. Franchetti GSI, Darmstadt, Germany
	Funding: This work was supported in part by the European Commission under the HORIZON 2020 project I.FAST, no. 101004730. Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. Possible figures-of-merit and pathways to ultimate colliders will also be explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB027
About •	paper received ※ 16 May 2021 paper accepted ※ 02 August 2021 issue date ※ 23 August 2021
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TUPAB028	Permanent Magnets Future Electron Ion Colliders at RHIC and LHeC	1401
	D. Trbojevic, S.J. Brooks, V. Litvinenko, T. Roser BNL, Upton, New York, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator.
	Poster TUPAB028 [2.720 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB028
About •	paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 30 August 2021
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TUPAB030	Superb Fixed Field Permanent Magnet Proton Therapy Gantry	1405
	D. Trbojevic, S.J. Brooks, T. Roser, N. Tsoupas BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. We present the top notch design of the proton therapy gantry made of permanent magnets with very strong focusing. This represents a superb solution fulfilling all cancer treatment requirements for all energies without changing any parameters. The proton energy range is between 60-250 MeV. The beam arrives to the patient focused at each required treatment energy. The scanning system is place between the end of the gantry and the patient. There are multiple advantages of this design: easy operation, no significant electrical power - just for the correction system, low weight, low cost. The design is based on the recent very successful commissioning of the permanent magnet ERL ’CBETA’ at Cornell University.
	Poster TUPAB030 [7.816 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB030
About •	paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 21 August 2021
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TUPAB031	Construction and Installation of the New CERN Proton Synchrotron Internal Beam Dumps	1409
	K.G. Andersen, M. Calviani, A. Cherif, T. Coiffet, A. De Macedo, S. Devidal, J.-M. Geisser, S.S. Gilardoni, M.M.J. Gillet, E. Grenier-Boley, J.M. Herediapresenter, A. Majbour, F. Monnet, M.R. Monteserin, F.-X. Nuiry, D. Pugnat, G. Romagnoli, Y.D.R. Seraphin, J.A.F. Somoza, N. Thaus CERN, Geneva 23, Switzerland
	In the framework of the CERN Large Hadron Collider Injectors Upgrade (LIU) Project, the Proton Synchrotron (PS) has been equipped with two new movable Internal Dumps (PSID), each of them capable of absorbing particle beams of an energy of up to 100 kJ. These dumps replace the old Internal Dumps, which have been operated in the accelerator complex since their installation in 1975 until their decommissioning and removal from the machine during the second LHC Long Shut down (LS2). This contribution will address the construction and testing phases of the new PSIDs, including the assembly of the dump core, its actuation system and the respective shielding, mechanical running-in tests, metrology adjustments, Ultra-High Vacuum (UHV) and impedance acceptance tests. The described installation work was completed successfully, and the new generation Dumps are currently operational in the PS machine.
	Poster TUPAB031 [3.146 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB031
About •	paper received ※ 18 May 2021 paper accepted ※ 27 May 2021 issue date ※ 26 August 2021
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TUPAB033	Photocathode Stress Test Bench at INFN LASA	1413
	D. Sertore, D. Giove, G. Guerini Rocco, L. Monaco INFN/LASA, Segrate (MI), Italy A. Bacci, F. Canella, S. Cialdi, I. Drebot, D. Giannotti, L. Serafini INFN-Milano, Milano, Italy D. Cipriani, E. Suerra Università degli Studi di Milano, Milano, Italy G. Galzerano POLIMI, Milano, Italy
	In the framework of the preparatory activities to the BriXSino project, a test bench for testing Cs₂Te photocathode at 100 MHz laser repetition rate has been installed at INFN LASA. This high repetition operation mode is foreseen to be the base operation mode of BriXSino and a qualification of the Cs₂Te photocathodes is a key component. While we are not at full specification due to the limited HV of the present DC gun, we discuss the status of the test bench and the initial results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB033
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 19 August 2021
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TUPAB034	Development of Multi-Alkali Antimonides Photocathodes for High-Brightness RF Photoinjectors	1416
	S.K. Mohanty, M. Krasilnikov, A. Oppelt, H.J. Qian, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Guerini Rocco, C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy
	Multi-alkali antimonide-based photocathodes are suitable candidate for the electron sources of next-generation high brightness RF photoinjectors due to their excellent photoemissive properties especially, like low thermal emittances and high sensitivity to visible light. The former stands out, paving the way towards CW operations. Based on the previous successful development of Cesium Telluride photocathodes, we are now channelling our efforts toward an R&D activity focused on KCsSb and NaKSb(Cs) photocathodes. Parallel to that R&D activity, we have installed a new dedicated photocathode production system at the INFN-LASA to start the preparation of these photocathodes for their test in the PITZ photoinjector at DESY in Zeuthen. In this paper, detailed experimental results obtained from the KCsSb, along with a preliminary result from the NaKSb(Cs) photocathode material as well as the status of the overall project are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB034
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 31 August 2021
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TUPAB035	ESS Medium Beta Cavities Status at INFN LASA	1420
	D. Sertore, M. Bertucci, M. Bonezzi, A. Bosotti, A. D’Ambros, A.T. Grimaldi, P. Michelato, L. Monaco, R. Paparella INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	INFN Milano contributes in-kind to the ESS ERIC Superconducting Linac supplying 36 cavities for the Medium Beta section of the proton accelerator. The production has reached completion, being all the cavities mechanical fabricated, BCP treated and, for most of them, also qualified with vertical test at cold. In this paper, we report on the results and lessons learnt and the actions taken both for quality control managing and recovery of the few cavities that did not reach the project goal after the first qualification test.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB035
About •	paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 18 August 2021
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TUPAB036	The Accelerator Design Progress for EIC Strong Hadron Cooling	1424
	E. Wang, S. Peggs, V. Ptitsyn, F.J. Willeke, W. Xu BNL, Upton, New York, USA S.V. Benson JLab, Newport News, Virginia, USA D. Douglas Douglas Consulting, York, Virginia, USA C.M. Gulliford, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes Xelera Research LLC, Ithaca, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy, The Electron-Ion Collider will achieve a luminosity of 10³⁴ cm^-2 s⁻¹ by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB036
About •	paper received ※ 16 May 2021 paper accepted ※ 11 June 2021 issue date ※ 01 September 2021
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TUPAB037	The Design of a High Charge Polarized Preinjector for the Electron-Ion Collider	1428
	E. Wang, W. Liu, V.H. Ranjbar, J. Skaritka, N. Tsoupas BNL, Upton, New York, USA J.M. Grames, J. Guo JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The design of the electron pre-injector of the Electron-Ion Collider (EIC) project to generate 4 x 7 nC bunch has been advancing to meet the requirements for injection into the Rapid Cycling Synchrotron (RCS). The major challenges are high charge transport and achieving small energy spread from 3 GHz traveling-wave plate(TWP). The designed preinjector includes the polarized electron source, bunching section, TWP Linac, zigzag phase space manipulation and spin rotator. In this report, we will discuss the RF frequency selection and the way to reduce energy spread down to 0.2% by longitudinal phase space manipulate. We will also report the results of beamline simulation using space charge code and the conceptual design of spin rotator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB037
About •	paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 27 August 2021
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TUPAB038	Simulation of the Filling Pattern Dependent Regenerative Beam Breakup Instabilities in Energy Recover Linacs	1431
	S. Setiniyaz, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Apsimon Cockcroft Institute, Lancaster University, Lancaster, United Kingdom P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The interaction of a transversely displaced beam with the higher modes (HOM) of the accelerating cavities causes building up HOM voltages in the cavity, which in turn kicks the beam and increases the offset further. This is known as regenerative beam breakup (BBU) instability and it sets the beam threshold current for the stable beam operation. A study by Setiniyaz et al.~[Setiniyaz2020] showed the filling pattern and recombination schemes of multi-turn energy recovery linacs (ERLs) can create many different beam loading transients, which can have a big impact on the cavity fundamental mode voltage and RF stabilizes. In this work, we extend the study of the filling pattern and recombination schemes to the BBU instabilities and threshold current. In the ERLs, the accelerated and decelerated bunches can be ordered differently while they pass through the cavity and form different filling patterns. Each pattern has a unique bunch energy sequence and bunch arrival times and hence interacts with cavity uniquely and thus drives BBU differently. In this paper, we introduce a simulation tool to investigate the filling pattern dependence of the ERL BBU instability. * S. Setiniyaz, R. Apsimon, and P. H. Williams, Phys. Rev. Accel. Beams 23, 072002, 2020.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB038
About •	paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 15 August 2021
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TUPAB040	Design Concept for the Second Interaction Region for Electron-Ion Collider	1435
	B.R. Gamage, V. Burkert, R. Ent, Y. Furletova, D.W. Higinbotham, A. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, D. Romanov, T. Satogata, A. Seryi, A.V. Sy, C. Weiss, M. Wiseman, W. Wittmer, Y. Zhang JLab, Newport News, Virginia, USA E.C. Aschenauer, J.S. Berg, A. Jentsch, A. Kiselev, C. Montag, R.B. Palmer, B. Parker, V. Ptitsyn, F.J. Willeke, H. Witte BNL, Upton, New York, USA C. Hyde ODU, Norfolk, Virginia, USA P. Nadel-Turonski SBU, Stony Brook, New York, USA
	Funding: Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 and Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The possibility of two interaction regions (IRs) is a design requirement for Electron-Ion Collider (EIC). There is also a significant interest from the nuclear physics community to have a 2nd IR with measurement capabilities complementary to those of the 1st IR. While the 2nd IR will be in operation over the entire energy range of ~20GeV to ~140GeV center of mass (CM). The 2nd IR can also provide an acceptance coverage complementary to that of the 1st. In this paper, we present a brief overview and the current progress of the 2nd IR design in terms of the parameters, magnet layout, and beam dynamics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB040
About •	paper received ※ 24 May 2021 paper accepted ※ 31 August 2021 issue date ※ 30 August 2021
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TUPAB041	Detector Solenoid Compensation for the Electron-Ion Collider	1439
	B.R. Gamage, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, A. Seryi, W. Wittmer, Y. Zhang JLab, Newport News, Virginia, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA A. Kiselev, H. Lovelace III, B. Parker, S. Peggs, S. Tepikian, F.J. Willeke, H. Witte, Q. Wu BNL, Upton, New York, USA
	Funding: Jefferson Science Associates, LLC Contract No. DE-AC05-06OR23177, Fermi Research Alliance, LLC Contract No. DE-AC02-07CH11359, and Brookhaven Science Associates, LLC Contract No. DE-SC0012704 The central detector in the present EIC design includes a 4 m long solenoid with an integrated strength of up to 12 Tm. The electron beam passes on-axis through the solenoid, but the hadron beam has an angle of 25 mrad. Thus the solenoid couples horizontal and vertical betatron motion in both electron and hadron storage rings, and causes a vertical closed orbit excursion in the hadron ring. The solenoid also couples the transverse and longitudinal motions of both beams, when crab cavities are also considered. In this paper, we present schemes for closed orbit correction and coupling compensation at the IP, including crabbing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB041
About •	paper received ※ 28 May 2021 paper accepted ※ 31 August 2021 issue date ※ 12 August 2021
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TUPAB042	Large Radial Shifts in the EIC Hadron Storage Ring	1443
	S. Peggs, J.S. Berg, K.A. Drees, X. Gu, C. Liu, H. Lovelace III, Y. Luo, G.J. Marr, A. Marusic, F. Méot, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, M. Valette, S. Verdú-Andrés BNL, Upton, New York, USA K.E. Deitrick Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA B.R. Gamage JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The Electron Ion Collider will collide hadrons in the Hadron Storage Ring (HSR) with ultra-relativistic electrons in the Electron Storage Ring. The HSR design trajectory includes a large radial shift over a large fraction of its circumference, in order to adjust the hadron path length to synchronize collisions over a broad range of hadron energies. The design trajectory goes on-axis through the magnets, crab cavities and other components in the six HSR Insertion Regions. This paper discusses the issues involved and reports on past and future beam experiments in the Relativistic Heavy Ion Collider, which will be upgraded to become the HSR.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB042
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021
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TUPAB044	Preliminary Study of the on-Axis Swap-Out Injection Scheme for the Southern Advanced Photon Source	1447
	Y. Han, X.H. Lu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China L. Huang, Y. Jiao, X. Liupresenter, S. Wang IHEP, Beijing, People’s Republic of China
	The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. The extremely low emittance will result in a very small dynamic aperture for the storage ring which makes it difficult to use the conventional off-axis accumulation injection. In this case, it is probably necessary to consider the transverse on-axis injection or the longitudinal injection. In this paper, the transverse on-axis swap-out injection scheme for the SAPS storage ring is presented. The preliminary parameters of the septum magnets and fast kickers are carefully evaluated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB044
About •	paper received ※ 17 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021
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TUPAB045	The Low Energy Injector Design for the Southern Advanced Photon Source	1450
	Y. Han IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, B. Li, X. Liupresenter, S. Wang IHEP, Beijing, People’s Republic of China
	The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. At present, two injector options are under consideration. One is a full energy booster plus a low energy injector, and another is a full energy linac injector. In this paper, a preliminary design of the low energy injector is presented, which consists of an DC thermionic electron gun, a bunching section and an accelerating section. The beam energy at the end of the injector is about 150 MeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB045
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 18 August 2021
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TUPAB046	Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source	1454
	X. Liu Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China Y. Jiao, B. Li, S. Wang IHEP, Beijing, People’s Republic of China
	A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021
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TUPAB047	Bunch Compressor Design in the Full Energy Linac Injector for the Southern Advanced Photon Source	1458
	B. Li IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, X. Liupresenter, S. Wang IHEP, Beijing, People’s Republic of China
	A mid-energy fourth-generation storage ring light source named the Southern Advanced Photon Source (SAPS), has been considered to be built neighboring the China Spallation Neutron Source (CSNS). A full energy linac has been proposed as an injector to the storage ring, with the capability to generate high brightness electron beams to feed a Free Electron Laser (FEL) at a later stage. To achieve the high peak current in FELs, space charge, RF structure wakefield, coherent synchrotron radiation (CSR), RF curvature, and the second-order momentum compaction factor should be carefully considered and optimized during the bunch compression processes. In this paper, physic design and simulation results of the bunch compressors are described.
	Poster TUPAB047 [1.918 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB047
About •	paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 28 August 2021
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TUPAB048	HMBA Optics Correction Experience at ESRF	1462
	S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Farvacque, T.P. Perron, P. Raimondi, S.M. White ESRF, Grenoble, France
	The ESRF-EBS storage ring, successfully commissioned in 2020, operates the HMBA lattice, first proposed in * and then adopted in several recent upgrade programs. The successful and timely commissioning of the storage is in large part due to the excellent optics control achieved over that period. Design performance were obtained with lower than predicted correction strengths, localized for the most part in the vicinity of sextupoles. This remarkable behavior is not only the result of the corrective actions taken during the commissioning but also of the extremely accurate conception and alignment of the machine. This report summarizes the steps that lead to the present performances and discusses their stability over time. * J.Biasci et al. Synchrotron Radiation News27, 8 (2014), https://doi.org/10.1080/08940886.2014.970931.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB048
About •	paper received ※ 10 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021
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TUPAB049	USSR HMBA Storage Ring Lattice Options	1466
	S.M. Liuzzo, N. Carmignani, L.R. Carver, J. Chavanne, L. Hoummi, J. Jacob, T.P. Perron, R. Versteegen, S.M. White ESRF, Grenoble, France I.A. Ashanin, V.S. Dyubkov, S.M. Polozov MEPhI, Moscow, Russia I.A. Ashanin, V.S. Dyubkov, T. Kulevoy, S.M. Polozov NRC, Moscow, Russia T. Kulevoy ITEP, Moscow, Russia
	Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution #287 Several new accelerator facilities will be built in Russia in a few years from now. One of those facilities is a 6GeV storage ring (SR) light source (USSR - Ultimate Source of Synchrotron Radiation) to be built in Protvino, near Moscow. The Cremlin+ project aims to incorporate in this activity the best experience of European Accelerator Laboratories. The design of the optics for this SR is presented here in two declinations leading to 70 pm-rad equilibrium horizontal emittance. The first is a 40 cells lattice, the second is the same but includes high field Short Bending magnet sources in each cell. Optics and high order multipole optimizations are performed to obtain sufficient lifetime and dynamic aperture for a conservative off-axis injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB049
About •	paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021
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TUPAB050	A Long Booster Option for the USSR 6 GeV Storage Ring	1470
	S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Hoummi, T.P. Perron, R. Versteegen, S.M. White ESRF, Grenoble, France I.A. Ashanin, S.M. Polozov MEPhI, Moscow, Russia I.A. Ashanin, T. Kulevoy, S.M. Polozov NRC, Moscow, Russia T. Kulevoy ITEP, Moscow, Russia
	Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution no. 287 The design of the optics of a full length 6 GeV booster for the USSR (Ultimate Source of Synchrotron Radiation) are presented. This option already followed with success by other laboratories, would allow to obtain a small emittance injected beam thus enabling smooth top-up operation. Details of the design inspired by the ESRF DBA lattice and the possible operating modes are described. The transfer lines booster to storage ring are also addressed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB050
About •	paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 24 August 2021
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TUPAB051	Elettra and Elettra 2.0	1474
	E. Karantzoulis, A. Carniel, D. Castronovo, S. Di Mitri, B. Diviacco, S. Krecic Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with the future upgrade concerning the new ultra-low emittance light source Elettra 2.0 that will provide ultra-high brilliance while the very short pulses feasibility study for time resolved experiments is in progress.
	Poster TUPAB051 [1.632 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB051
About •	paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 20 August 2021
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TUPAB052	Current Study of Applying Machine Learning to Accelerator Physics at IHEP	1477
	J. Wan, Y. Jiao IHEP, Beijing, People’s Republic of China
	Funding: National Natural Science Foundation of China(No.11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904) and National Key R&D Program of China(No.2016YFA0401900). In recent years, machine learning (ML) has attracted increasing interest among the accelerator field. As a complex collection of multiple physical subsystems, the design and operation of an accelerator can be very nonlinear and complicated, while ML is taken as a powerful tool to solve such nonlinear and complicated problems. In this study, we report on several successful applications of ML to accelerator physics at IHEP. The nonlinear dynamics optimization of the High Energy Photon Source (HEPS) that is a 4th-generation light source is a challenging topic. In this optimization, we use a ML surrogate model to fast select the potentially competitive solutions for a multiobjective genetic algorithm that can significantly improve the convergence rate and the diversity among obtained solutions. Besides, we also tried to apply a generative adversarial net to solve one-to-many problems of longitudinal beam current profile shaping. Unlike most supervised machine learning methods than cannot learn one-to-many maps, the generative adversarial net-based method is able to predict multiple solutions instead of one for a 4-dipole chicane to realize several desired custom current profiles.
	Poster TUPAB052 [0.913 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB052
About •	paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 27 August 2021
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TUPAB053	Design Progress of ALS-U 3rd-Harmonic Cavity	1481
	T.H. Luo, K.M. Baptiste, S. De Santis, D. Li, J.W. Staples, M. Venturini LBNL, Berkeley, California, USA H.Q. Feng TUB, Beijing, People’s Republic of China
	Funding: Director, Office of Science, Office of Basic Energy Sciences, and LDRD Program of Lawrence Berkeley National Laboratory, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 A higher-harmonic rf cavity (HHC) system is required in the ALS-U storage ring to lengthen the bunches, reduce intrabeam-scattering effects, and improve Touschek beam lifetime. A 3rd harmonic, normal conducting, passive-cavity system has been chosen based on beam-dynamics requirements and cost considerations. We have explored two options for ALS-U 3HC system: a high-R/Q re-entrant cavity with waveguide HOM dampers, and a low-R/Q system with two elliptical cavities and HOM beam line absorbers. In this paper, we present the recent progress on the cavity design and related beam dynamics studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB053
About •	paper received ※ 19 May 2021 paper accepted ※ 11 June 2021 issue date ※ 14 August 2021
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TUPAB054	CDR BASELINE LATTICE FOR THE UPGRADE OF SOLEIL	1485
	A. Loulergue, D. Amorim, P. Brunelle, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Previous MBA studies converged toward a lattice composed of 20 7BA solution elaborated by adopting the sextupole pairing scheme with dispersion bumps originally developed at the ESRF-EBS. It provided a low natural horizontal emittance value of 70-80 pm-rad range at an energy of 2.75 GeV. Due to difficulties to accommodate such lattice geometry in the SOLEIL present tunnel as well as to preserve at best the beamline positioning, alternative lattice based on HOA (Higher-Order Achromat) type cell has been recently investigated. The HOA type cell being more modular and possibly exhibiting larger momentum acceptance as well as low emittances, a solution alternating 7BA and 4BA cells was then identified as the best to adapt the current beamline positioning. The SOLEIL CDR upgrade reference lattice is then composed of 20 HOA cells alternating 7BA and 4BA giving a natural horizontal emittance of 80 pm-rad. The linear and non-linear beam dynamic properties of the lattice along with the possibility of horizontal off-axis injection at full betatron coupling are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB054
About •	paper received ※ 21 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021
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TUPAB057	Carbon Beam at I-3 Injector for Semiconductor Implantation	1489
	A.A. Losev, P.N. Alekseev, N.N. Alexeev, T. Kulevoypresenter, A.D. Milyachenko, Yu.A. Satov, A. Shumshurov ITEP, Moscow, Russia P.B. Lagov NUST MISIS, Moscow, Russia M.E. Letovaltseva MIREA, Moscow, Russia Y.S. Pavlov IPCE RAS, Moscow, Russia
	Carbon implantation can be effectively used for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures. When carbon is implanted, more stable recombination centers are formed and silicon is not doped with additional impurities, as for example, when irradiated with protons or helium ions. Economically, such a process competes with alternative methods, and is more efficient for obtaining small lifetimes (several nanoseconds). I-3 ion injector with laser-plasma ion source in Institute for theoretical and experimental physics (ITEP) is used as ion implanter in semiconductors. The ion source uses pulsed CO₂ laser setup with radiation-flux density of 10¹¹ W/cm² at target surface. The ion source produces beams of various ions from solid targets. The generated ion beam is accelerated in the two gap RF resonator at voltage of up to 2 MV per gap. Resulting beam energy is up to 4 MV per charge. Parameters of carbon ion beam generated and used for semiconductor samples irradiation during experiments for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures are presented.
	Poster TUPAB057 [0.630 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB057
About •	paper received ※ 15 May 2021 paper accepted ※ 28 May 2021 issue date ※ 01 September 2021
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TUPAB058	Online Optimizations of Several Observable Parameters at the Advanced Photon Source	1492
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Online optimizations are known to be powerful tools which may quickly and efficiently improve the particle accelerator key performance parameters in a model-independent way. In this paper, it is presented on the online optimizations of several observable parameters at the Advanced Photon Source storage ring. These observable parameters include the beam lifetime, injection efficiency and topup efficiency, transverse beam sizes, and turn by turn beam position monitors. It is demonstrated that the particle accelerator performance may be greatly enhanced in a relatively short time frame, by optimizing these observable parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB058
About •	paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021
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TUPAB059	Measurement of the Advanced Photon Source Lifetime at Different Level of Beta-Beating	1496
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Linear optics correction of a particle accelerator may not be perfect due to the existence of different errors sources in response matrix measurements and optics correction process. Previous numerical simulation study has shown that the single particle beam dynamics performance may be highly correlated with the level of residual beta-beating. In this paper, the machine study results on beam lifetime of the APS storage ring is presented. The experiment is performed at different level of predefined beta-beating with negligible betatron tunes variations. As expected, the measured beam lifetime has an inverse correlation with the level of beta-beating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB059
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 16 August 2021
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TUPAB060	Machine Learning on Beam Lifetime and Top-Up Efficiency	1499
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Both unsupervised and supervised machine learning techniques are employed for automatic clustering, modeling and prediction of Advanced Photon Source (APS) storage ring beam lifetime and top-up efficiency archived in operations. The naive Bayes classifier algorithm is developed and combined with k-means clustering to improve accuracy, where the unsupervised clustering of APS beam lifetime and top-up efficiency is consistent with either true label from data archive or Gaussian kernel density estimation. Artificial neural network algorithms have been developed, and employed for training and modelling the arbitrary relations of beam lifetime and top-up efficiency on many observable parameters. The predictions from artificial neural network reasonably agree with the APS operation data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB060
About •	paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021
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TUPAB061	Anomaly Detection by Principal Component Analysis and Autoencoder Approach	1502
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Several different approach are employed to identify the abnormal events in some Advanced Photon Source (APS) operation archived dataset, where dimensionality reduction are performed by either principal component analysis or autoencoder artificial neural network. It is observed that the APS stored beam dump event, which is triggered by magnet power supply fault, may be predicted by analyzing the magnets capacitor temperatures dataset. There is reasonable agreement among two principal component analysis based approaches and the autoencoder artificial neural network approach, on predicting future overall system fault which may result in a stored beam dump in the APS storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB061
About •	paper received ※ 22 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021
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TUPAB062	Expediting APS-U Long-Term Particle Tracking with Arbitrary Order Taylor Map	1505
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Truncated power series algebra was integrated within explicit symplectic integration to formulate an arbitrary order multivariate Taylor map for any given particle accelerator lattice. Tracking simulation performed with these Taylor maps shows good long term stability and physics accuracy. There is good agreement in long term particle tracking simulations between Taylor map and element by element tracking of APS-U lattice, when the particle is within 1 to 10 σ of stored beam. It is demonstrated that most of the lower order resonance driving terms, plus chromatic and geometric aberrations are reasonably preserved by the Taylor map approach. Last but maybe most important, the computation time is reduced by a factor of 20 to 50, when compared to symplectic integration based element by element tracking.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB062
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 29 August 2021
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TUPAB063	Study of PF-Ring Infrastructure Improvements Using Temperature Measurements in the Ring Tunnel	1508
	N. Nakamura, K. Haga, T. Nogami, M. Tadano KEK, Ibaraki, Japan
	Temperature measurements have been performed in the PF-ring tunnel in order to understand the infrastructure performance and the temperature stability towards the PF upgrade project, where better beam stability will be required. Based on the temperature measurements, possible improvements of the PF-ring infrastructure such as an air-conditioning system have been studied to enhance the temperature stability in the PF-ring tunnel. In this paper, we present results of the temperature measurements in the PF-ring tunnel and a proposal of the PF-ring infrastructure improvements for the temperature stabilization.
	Poster TUPAB063 [6.169 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB063
About •	paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB064	Specifications and Performance of a Chicane Magnet for the cERL IR-FEL	1512
	N. Nakamura, K. Harada, N. Higashi, Y. Honda, R. Kato, C. Mitsuda, S. Nagahashi, T. Obina, H. Sakai, M. Shimada, H. Takaki, O.A. Tanaka KEK, Ibaraki, Japan Y. Lu Sokendai, Ibaraki, Japan
	Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)". The IR-FEL was constructed in the Compact ERL (cERL) at KEK from October 2019 to May 2020 for the purpose of developing high-power mid-infrared lasers for high-efficiency laser processing utilizing molecular vibrational absorption. The chicane magnet was newly installed between two IR-FEL undulators in the cERL in order to increase the FEL gain and pulse energy by converting the energy modulation to the density modulation in an electron bunch. It consists of three dipole magnets with laminated yokes made of 0.1-mm-thick permalloy sheets and the coil currents of the three magnets are independently controlled by three power supplies with the maximum current of 10 A. The maximum closed orbit bump made by the chicane magnetic field has the longitudinal dispersion(R56) of -6 mm. The coil-current ratio of the three dipole magnets was tuned after installation to make its orbit bumps closed and then the chicane magnet was used in the FEL operation. We present specifications and operational performance of the chicane magnet.
	Poster TUPAB064 [4.053 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB064
About •	paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 25 August 2021
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TUPAB065	Solaris Storage Ring Performance After 6 Years of Operation	1515
	A.I. Wawrzyniak, A. Curcio, K. Gula, M.A. Knafel, G.W. Kowalski, A.M. Marendziak, R. Panaś, M. Waniczek, M. Wiśniowski NSRC SOLARIS, Kraków, Poland
	Solaris is a third generation light source operating since 2015 in Kraków, Poland. Between 2015 and 2018 the synchrotron as well as two beamlines were commissioned. During commissioning phases, the good performance of Solaris storage ring has been reached. The beam optics was brought close to the design one. Since October 2018 Solaris storage ring is in the user operation mode. Moreover, two other beamlines with the elliptically polarized undulators used as source were installed and are under commissioning now. In 2020 the total beam availability of 93% was reached with the average circulating current of 400 mA and the total lifetime of 15 h. Over last two years few improvements of the storage ring were done to optimize the storage ring performance. The Landau cavities were tuned to improve the Touschek lifetime and suppress the instabilities. Two diagnostics beamlines were installed and commissioned allowing for the beam sizes in three planes and emittance measurements. The storage ring optics was fine-tuned to increase the dynamic aperture.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB065
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB066	Status of the Short-Pulse Source at DELTA	1518
	A. Held, B. Büsing, H. Kaiser, S. Khan, D. Krieg, A.R. Krishnan, C. Mai DELTA, Dortmund, Germany
	Funding: Work supported by BMBF (05K19PEB). At the synchrotron light source DELTA operated by the TU Dortmund University, the short-pulse source employs the seeding scheme coherent harmonic generation (CHG) and provides ultrashort pulses in the vacuum ultraviolet and terahertz regime. Here, the interaction of laser pulses with the stored electron bunches result in a modulation of the longitudinal electron density which gives rise to coherent emission at harmonics of the laser wavelength. Recently, investigations of the influence of the Gouy phase shift at the focal point of the laser pulses on the laser-electron interaction have been performed. For the planned upgrade towards the more sophisticated seeding scheme echo-enabled harmonic generation (EEHG) featuring a twofold laser-electron interaction, simulations of the ideal parameters of the laser beams have been carried out.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB066
About •	paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 28 August 2021
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TUPAB067	Production of 120 MeV Gamma-ray Beams at Duke FEL and HIGS Facility	1522
	S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, Y.K. Wu, J. Yan FEL/Duke University, Durham, North Carolina, USA M.W. Ahmed, M. Sikora TUNL, Durham, North Carolina, USA H. Ehlers, L.O. Jensen, L. Kochanneck Laser Zentrum Hannover, Hannover, Germany
	Funding: This work is supported by the US DoE grant #DE-FG02-97ER41033 In this paper we report extension of the operational energy of the gamma ray beams produced at Duke High Intensity Gamma-ray Source (HIGS) up to ~120MeV, opening up a new high energy region of gamma rays for photonuclear physics research. This achievement is based upon development of radiation robust, thermally stable, high-reflectivity fluoride (LaF3/MgF2) multilayer VUV FEL mirrors, enabling us to maintain stable high intensity FEL lasing at the wavelengths of around 175nm. We discuss the challenges of HIGS operation at high gamma and high electron beam energies with the downstream FEL mirror exposed to extremely hush radiation. The experience of the first HIGS user operation with high intensity, high gamma-ray beam energies (85 and ~120MeV) using these new mirrors is also discussed.
	Poster TUPAB067 [1.023 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB067
About •	paper received ※ 30 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021
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TUPAB069	The Sabina Terahertz/Infrared Beamline at SPARC-Lab Facility	1525
	S. Macis La Sapienza University of Rome, Rome, Italy M. Bellaveglia, M. Cestelli Guidi, E. Chiadroni, F. Dipace, A. Ghigo, L. Giannessi, A. Giribono, L. Sabbatini, C. Vaccarezza INFN/LNF, Frascati, Italy A. Doria, A. Petralia ENEA C.R. Frascati, Frascati (Roma), Italy S. Lupi Sapienza University of Rome, Roma, Italy V. Petrillo INFN-Milano, Milano, Italy
	Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program. Following the EU Terahertz (THz) Road Map, high-intensity, ps-long, THz)/Infrared (IR) radiation is going to become a fundamental spectroscopy tool for probing and control low-energy quantum systems ranging from graphene, and Topological Insulators, to novel superconductors* **. In the framework of the SABINA project, a novel THz/IR beamline based on an APPLE-X undulator emission will be developed at the SPARC-Lab facility at LNF-INFN. Light will be propagated from the SPARC-Lab to a new user lab facility nearly 20 m far away. This beamline will cover a broad spectral region from 3 THz to 30 THz, showing ps- pulses and energy of tens of µJ with variable polarization from linear to circular. The corresponding electric fields up to 10 MV/cm, are able to induce non-linear phenomena in many quantum systems. The beamline, open to user experiments, will be equipped with a 5 T magnetic cryostat and will be synchronized with a fs laser for THz/IR pump, VIS/UV probe experiments. [] S.S. Dhillon et al., J. Phys. D: Appl. Phys. 50, 043001 (2017); [] F. Giorgianni et al., Nature Commun. 7, 11421 (2016); [*] P. Di Pietro et al., Phys. Rev. Lett. 124, 226403 (2020);
	Poster TUPAB069 [0.884 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB069
About •	paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021
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TUPAB071	Beam Line Design and Instrumentation for THz@PITZ - the Proof-of-Principle Experiment on a THz SASE FEL at the PITZ Facility	1528
	T. Weilbach, P. Boonpornprasert, G.Z. Georgiev, G. Koss, M. Krasilnikov, X. Li, A. Lueangaramwong, F. Mueller, A. Oppelt, S. Philipp, F. Stephan, L.V. Vu DESY Zeuthen, Zeuthen, Germany H. Shaker CLS, Saskatoon, Saskatchewan, Canada
	In order to allow THz pump-X-ray probe experiments at full bunch repetition rate for users at the European XFEL, the Photo Injector Test Facility at DESY in Zeuthen (PITZ) is building a prototype of an accelerator-based THz source. The goal is to generate THz SASE FEL radiation with a mJ energy level per bunch using an LCLS-I undulator driven by the electron beam from PITZ. Therefore, the existing PITZ beam line is extended into a tunnel annex downstream of the existing accelerator tunnel. The beam line extension in the PITZ tunnel consists of three quadrupole magnets, a bunch compressor, a collimation system and a beam dump. In the second tunnel a dipole magnet allows to serve two beam lines, one of them the THz@PITZ beam line. It consists of one LCLS-I undulator for the production of the THz radiation, a quadrupole triplet in front of it and a quadrupole doublet behind it. For the electron beam diagnostic six new screen stations are built, three of them also allow for the observation of the THz radiation for measurements. In addition six BPMs and a new BLM system for machine protection and FEL gain curve measurement will be installed. The progress of this work will be presented.
	Poster TUPAB071 [1.978 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB071
About •	paper received ※ 18 May 2021 paper accepted ※ 14 June 2021 issue date ※ 13 August 2021
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TUPAB072	The Status of a Grating Monochromator for Soft X-Ray Self-Seeding Experiment at SHINE	1532
	K.Q. Zhang SSRF, Shanghai, People’s Republic of China H.X. Deng, C. Feng, B. Liu, T. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	The research status of a grating monochromator for soft X-ray self-seeding experiment at SHINE has been presented in this paper. The monochromator system includes the vacuum cavity, optical elements, and mechanical movement devices. Until now, the vacuum cavity has finished the manufactured process completely, the optical mirrors have finished machining and measured by the longitudinal trace profiler (LTP) and atomic force microscope (AFM). To make sure the monochromator system can achieve an optical resolution of 1/10000 at the photon energy of 700-1300eV, the system has been integrated and tested recently. In this year, the previous online experiment will be performed in the shanghai soft X-ray free-electron laser (FEL) user facility.
	Poster TUPAB072 [0.717 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB072
About •	paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 01 September 2021
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TUPAB073	The Design of EEHG Cascaded Harmonic Lasing for SXFEL User Facility	1536
	K.Q. Zhang, C. Feng SSRF, Shanghai, People’s Republic of China H.X. Deng, B. Liu, T. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	The preliminary design and simulation results of EEHG cascaded harmonic lasing for the SXFEL user facility have been presented in this paper. Using the basic seeded beamline of the SXFEL user facility, the designed parameters are optimized to obtain full coherent FEL output at the 90th harmonic of a 265 nm seed laser. According to the designed parameters and the layout of the SXFEL user facility, the detailed simulations are carried out, the results show that the seeded beamline of the SXFEL user facility can generate 2.93 nm full coherent radiation by the proposed method, which indicates that the method can extend the photon energy range of a seeded FEL and the method can be achieved at the SXFEL user facility.
	Poster TUPAB073 [0.955 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB073
About •	paper received ※ 11 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021
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TUPAB074	S-Band Transverse Deflecting Structure Design for CompactLight	1540
	X.W. Wu, W. Wuensch CERN, Meyrin, Switzerland S. Di Mitri Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy N. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, which is based on high-gradient X-band (12 GHz) structures. However, to carry out pump-and-probe experiments in the project, two-bunch operation with a spacing of 10 X-band rf cycles is proposed. A sub-harmonic transverse deflecting structure working at S-band is proposed to direct the two bunches into two separate FEL lines. The two FEL pulses will have independently tunable wavelengths and can be combined in a single experiment with a temporal delay between pulses of ± 100 fs. The rf design of the transverse deflector is presented in this paper.
	Poster TUPAB074 [1.557 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB074
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 21 August 2021
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TUPAB076	High-Gradient Breakdown Studies of an X-Band Accelerating Structure Operated in the Reversed Taper Direction	1543
	X.W. Wu, N. Catalán Lasheras, A. Grudiev, G. McMonagle, I. Syratchev, W. Wuensch CERN, Meyrin, Switzerland M. Boronat IFIC, Valencia, Spain A. Castilla, A.V. Edwards, W.L. Millar Lancaster University, Lancaster, United Kingdom
	The results of high-gradient tests of a tapered X-band traveling-wave accelerator structure powered in reversed direction are presented. Powering the tapered structure from the small aperture, normally output, at the end of the structure provides unique conditions for the study of gradient limits. This allows high fields in the first cell for a comparatively low input power and a field distribution that rapidly falls off along the length of the structure. A maximum gradient of 130 MV/m in the first cell at a pulse length of 100 ns was reached for an input power of 31.9 MW. Details of the conditioning and operation at high-gradient are presented. Various breakdown rate measurements were conducted at different power levels and rf pulse widths. The structure was standard T24 CLIC test structure and was tested in Xbox-3 at CERN.
	Poster TUPAB076 [1.077 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB076
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 12 August 2021
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TUPAB077	Novel Open Cavity for Rotating Mode SLED-Type RF Pulse Compressors	1547
	X.W. Wu, A. Grudiev CERN, Meyrin, Switzerland
	A new X-band high-power rotating mode SLAC Energy Doubler (SLED)-type rf pulse compressor is proposed. It is based on a novel cavity type, a single open bowl-shape energy storage cavity with high Q₀ and compact size, which is coupled to the waveguide using a compact rotating mode launcher. The novel cavity type is applied to the rf pulse compression system of the main linac rf module of the klystron-based option of the Compact Linear Collider (CLIC). Quasi-spherical rotating modes of \rm{TE}_1,2,4 and \rm{TE}_1,2,13 are proposed for the correction cavity and storage cavity of the rf pulse compression system respectively. The storage cavity working at \rm{TE}_1,2,13 has a Q₀ of 240000 and a diameter less than 33 cm. The design of the pulse compressor and in particular of the high-Q cavity will be presented in detail.
	Poster TUPAB077 [1.229 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB077
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021
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TUPAB078	Relative Timing Jitter Effects on Two-stage Seeded FEL at SHINE	1551
	H.X. Yang SINAP, Shanghai, People’s Republic of China H.X. Deng, B. Liu, D. Wang, K.S. Zhou SARI-CAS, Pudong, Shanghai, People’s Republic of China
	Funding: The National Key Research and Development Program of China (Grants No. 2016YFA0401901, No. 2018YFE0103100) and the National Natural Science Foundation of China (Grants No. 11935020, No. 11775293). The synchronization between the ultrashort electron beam and external seed laser is essential for seeded FELs, especially for a multi-stage one. In this paper, we demonstrate a simple method to obtain the correlations between the pulse energy and relative timing jitter for evaluating the corresponding effects. In this method, the sensitivity of the output FEL performance against electron beam properties is demonstrated by scanning the electron beam and seed lasers, and the fitted curve is used to predict the pulse energy in different timing jitter by random sampling. The results indicate that the pulse energy of the first-stage EEHG is more stable than the second-stage HGHG. Meanwhile, the rise of bunch charge from 100 pC to 300 pC can reduce the timing control requirement by a factor of least 3 for the RMS timing jitter in our numerical simulations based on the parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. The timing jitter study can demonstrate the feasibility of the EEHG-HGHG cascading scheme in different current profiles for generating Fourier-transform-limited soft X-ray FEL.
	Poster TUPAB078 [0.866 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB078
About •	paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021
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TUPAB079	Using ER@CEBAF to Show that a Multipass ERL Can Drive an XFEL	1555
	G. Perez-Segurana Cockcroft Institute, Lancaster University, Lancaster, United Kingdom I.R. Bailey, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom I.R. Bailey Lancaster University, Lancaster, United Kingdom R.M. Bodenstein, S.A. Bogacz, D. Douglas, Y. Roblin, T. Satogata JLab, Newport News, Virginia, USA T. Satogata ODU, Norfolk, Virginia, USA P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility as an option for a potential UK-XFEL. Energy Recovery enables multi-MHz FEL sources, for example, an X-ray FEL oscillator or regenerative amplifier FEL. Additionally, combining with external lasers and/or self-interaction would provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power for nuclear and particle physics applications. An opportunity exists to demonstrate the necessary point-to-parallel longitudinal matches to drive an XFEL and successfully energy recover at the upcoming 5-pass up, 5-pass down Energy Recovery experiment on CEBAF at JLab termed ER@CEBAF. We show candidate matches and simulations supporting the minimal necessary modifications to CEBAF this will require. This includes linearisation of the longitudinal phase space in the injector and a reduction in the dispersion of the arcs, both of which increase the energy acceptance of CEBAF. We expect to commence initial tests of these adaptations on CEBAF during 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB079
About •	paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021
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TUPAB080	Design and Status of the Beam Switchyard of the Shanghai Soft X-Ray FEL User Facility	1559
	S. Chen, R. Wang SSRF, Shanghai, People’s Republic of China H.X. Deng, C. Feng, X. Fu, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	SXFEL-UF, a soft X-ray FEL user facility located in Shanghai, has been upgraded from the existing test facility. Electron energy increases from 840 MeV to 1.5 GeV and a SASE FEL line will be added besides the existing seeding FEL line. It has started commissioning since early this year. In order for simultaneous operation of the two FEL lines, a beam switchyard is built between the linac and the two FEL lines. In this paper, the physics design of the beam switchyard is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB080
About •	paper received ※ 19 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021
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TUPAB081	Design of the Beam Distribution System of SHINE	1562
	S. Chen, M. Gu, R. Wang SSRF, Shanghai, People’s Republic of China H.X. Deng, X. Fu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	In shanghai, a hard X-ray free electron laser project named SHINE is under design. It will be based on a superconducting linac running in CW mode. On the first stage, there will be three parallel undulator lines downstream the linac. For simultaneous operation of the three undulator lines, a beam distribution system based on fast kickers will be installed between linac and undulator lines. The physics design of this beam distribution system is described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB081
About •	paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 22 August 2021
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TUPAB082	Analysis of the Effect of Energy Chirp in Implementing EEHG at SXL	1566
	M.A. Pop, F. Curbis, B.S. Kyle, S.P. Pirani, W. Qin, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden F. Curbis, S. Werin Lund University, Lund, Sweden W. Qin DESY, Hamburg, Germany
	As a part of the efforts to improve the longitudinal coherence in the design of the Soft X-ray FEL (the SXL) at MAX IV, we present a possible implementation of the EEHG harmonic seeding scheme partly integrated into the second bunch compressor of the existing LINAC. A special focus is given to the effect of CSR on the resulting EEHG bunching and on how this unwanted effect might be controlled.
	Poster TUPAB082 [1.825 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB082
About •	paper received ※ 15 May 2021 paper accepted ※ 28 July 2021 issue date ※ 17 August 2021
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TUPAB083	Dual Energies in the LCLS Copper Linac	1570
	F.-J. Decker, C. Bianchini Mattison, D.K. Bohler, A. Brachmann, W.S. Colocho, S. Condamoor, M.L. Gibbs, K.H. Kim, A.A. Lutman, T.J. Maxwell, J.A. Mock, H.-D. Nuhn, J.C. Sheppard, H. Smith, T.J. Smith, M. Stanek, S. Zelazny, Z. Zhang, C.M. Zimmer SLAC, Menlo Park, California, USA
	For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the superconducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.
	Poster TUPAB083 [0.479 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB083
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021
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Paper

Title

Page

DAΦNE Commissioning for SIDDHARTA-2 Experiment

1322

C. Milardi, D. Alesini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, A. D’Uffizi, A. De Santis, C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, G. Franzini, A. Gallo, S. Incremona, A. Michelotti, L. Pellegrino, L. Piersanti, R. Ricci, U. Rotundo, L. Sabbatini, A. Stecchi, A. Stella, A. Vannozzi, M. Zobov
INFN/LNF, Frascati, Italy
J. Chavanne, G. Le Bec, P. Raimondi
ESRF, Grenoble, France

DAΦNE, the Frascati lepton collider, has completed the preparatory phase in order to deliver luminosity to the SIDDHARTA-2 detector. DAΦNE colliding rings rely on a new interaction region, which implements the well-established Crab-Waist collision scheme, and includes a low-beta section equipped with newly designed permanent magnet quadrupoles, and vacuum components. Diagnostics tools have been improved, especially the ones used to keep under control the beam-beam interaction. The horizontal feedback in the positron ring has been potentiated in order to achieve a higher positron current. Luminosity diagnostics have been also updated so to be compatible with the new detector design. The commissioning was initially focused on recovering the optimal dynamical vacuum conditions, outlining alignment errors, and optimizing ring optics. For this reason, a detuned optics, featured by relaxed low-b condition at the interaction point and Crab-Waist Sestupoles off, has been applied. In a second stage a low-b optics has been implemented to test collisions with a preliminary setup of the experiment detector. Machine preparation and the first luminosity results are presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB001

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021

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TUPAB002

Round Colliding Beams: Successful Operation Experience

1326

D.B. Shwartz, O.V. Belikov, D.E. Berkaev, D.B. Burenkov, V.S. Denisov, A.S. Kasaev, A.N. Kirpotin, S.A. Kladov, I. Koop, A.A. Krasnov, A.V. Kupurzhanov, G.Y. Kurkin, M.A. Lyalin, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, Yu.A. Rogovsky, A.M. Semenov, A.I. Senchenko, L.E. Serdakov, D.N. Shatilov, P.Yu. Shatunov, Y.M. Shatunov, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia
S.A. Kladov, I. Koop, A.A. Krasnov, M.A. Lyalin, E. Perevedentsev, Yu.A. Rogovsky, Y.M. Shatunov, D.B. Shwartz
NSU, Novosibirsk, Russia

VEPP-2000 electron-positron collider operating in the beam energy range of 150-1000 MeV is the only machine originally designed for and successfully exploiting Round Beams Concept. After injection chain upgrade including link to the new BINP injection complex VEPP-2000 proceeded with data taking since 2017 with luminosity limited only by beam-beam effects. At the low energies (300-600 MeV/beam) the novel technique of effective emittance controlled increase by weak coherent beam shaking allowed to suppress the limiting flip-flop effect and resulted in additional luminosity gain factor of 4. The averaged delivered luminosity at the omega-meson production energy (2*391 MeV) achieved L = 2*10³¹cm^-2s⁻¹/IP. At the top energies above nucleon-antinucleon production threshold the stable operation with luminosity of L = 5*10³¹cm^-2s⁻¹/IP resulted in high average data taking rate of 2 pb^-1/day in 2020.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB002

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paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021

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TUPAB003

Final Focus Solenoids Beam-Based Positioning Tests

1330

D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia
D.B. Shwartz
NSU, Novosibirsk, Russia

The final focusing at the VEPP-2000 electron-positron collider is done by 13 T superconducting solenoids. The misalignment of solenoids not only provides closed orbit distortions but also harmful for dynamic aperture reduction due to strong nonlinear fringe fields. The final beam-based alignment of solenoids was foreseen but turned out to be not a trivial procedure. Here we present the test study of solenoids positioning reconstruction procedure based on circulating beam orbit responses.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB003

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paper received ※ 22 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021

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TUPAB004

Comparison of Accelerator Codes for Simulation of Lepton Colliders

1334

L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland

This paper compares simulation results obtained with SAD, MAD-X and the PTC implementation in MADX for the design studies of the FCC-ee. On-momentum and off-momentum optics are explored for the various programs. Particle tracking with and without synchrotron radiation are used to compare amplitude detuning and emittance. Finally, this paper outlines how well-established SAD features such as tapering have recently been integrated into MADX.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB004

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paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 26 August 2021

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TUPAB005

Emittance Estimates for the Future Circular Collider

1338

L. van Riesen-Haupt, T.K. Charles, R. Tomás García, F. Zimmermann
CERN, Meyrin, Switzerland
T.K. Charles
The University of Liverpool, Liverpool, United Kingdom

The alignment strategy of the FCC-ee has a large impact on its luminosity. Larger alignment tolerances result in increased coupling and a subsequently higher vertical emittance. At the same time, tighter alignment tolerances around the 100 km ring are a major cost driver. This paper applies analytical emittance estimate methods to the FCC-ee and compares their predictions to data from simulations with different alignment tolerances. These methods can be used to help understand the impact of misalignments of certain magnet groups and to come up with an efficient alignment strategy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB005

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021

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TUPAB006

The Impact of Beam Position Monitor Tilts on Coupling Measurements

1342

L. van Riesen-Haupt, R. Tomás García
CERN, Meyrin, Switzerland

The measurement and correction of coupling resonance driving terms is a key tool for improving the performance of synchrotrons. These terms are measured by exciting the beam and observing the subsequent motion in the horizontal and vertical planes through beam position monitors. This paper outlines the impact of tilt errors in these monitors to the distortion of the amount of coupling measured between the planes and how the computation of the resonance driving terms is affected by these tilts. It also attempts to use these results for mimicking tilt errors in simulations and discusses how discrepancies in measured resonance driving terms could be used to estimate the tilt errors that cause them.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB006

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 12 August 2021

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TUPAB007

A Correction Scheme for the Magnet Imperfection on the CEPC Collider Ring

1346

B. Wang, Y. Wangpresenter, Y. Wei, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

This paper describes the error correction scheme for the CEPC CDR lattice in Higgs mode, which has a small beta function at the interaction point. The low emittance optics has an enhanced sensitivity to the magnet misalignments and field errors, especially for the final focus quadrupole misalignment. The magnet imperfection will cause the closed orbit distortion and optics distortion. The correction scheme for these magnet imperfections includes the closed orbit correction, the dispersion correction, the beta function correction and the betatron coupling correction. The resulting performance and the dynamic aperture for the corrected lattice are studied.

Poster TUPAB007 [1.075 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB007

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paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021

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TUPAB008

Progress of the First-Turn Commissioning Simulations for HEPS

1349

B. Wang, Z. Duan, D. Ji, Y. Jiaopresenter, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is 6 GeV, kilometer-scale, 4th generation storage ring light source. The lattice has an ultralow emittance and strong focusing such that the beam dynamics is very sensitive to the magnet misalignments and other error sources. Getting the first turn and establishing the closed orbit is essential for accelerator commissioning. This paper describes a simulation algorithm for achieving the first turn commission based on the latest HEPS storage ring lattice. We developed a new accelerator toolbox (AT)-based program for automatic optimizing the first turn commissioning. The algorithm and simulation results will be presented in this paper.

Poster TUPAB008 [0.646 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB008

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paper received ※ 14 May 2021 paper accepted ※ 11 June 2021 issue date ※ 28 August 2021

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TUPAB009

SuperKEKB Optics Measurements Using Turn-by-Turn Beam Position Data

1352

J. Keintzel, R. Tomás García
CERN, Geneva, Switzerland
H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, M. Tobiyama, R.J. Yang
KEK, Ibaraki, Japan

SuperKEKB, an asymmetric electron-positron collider, has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} using crab-waist collision scheme. In order to reach the design value of 6×10³⁵ \si{cm^-2s^-1} a vertical beta function at the interaction point of §I{0.3}{mm} is required, demanding unprecedented optics control. Turn-by-turn beam position data could enable fast optics measurements for rapid identification of unexpected error sources. Experiments exploring various data acquisition techniques at different squeezing steps during commissioning are presented and compared to results obtained from closed orbit distortion.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB009

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021

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TUPAB010

Impact of Bunch Current on Optics Measurements in SuperKEKB

1356

J. Keintzel, R. Tomás García, F. Zimmermann
CERN, Geneva, Switzerland
T. Ishibashi, H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, S. Terui, M. Tobiyama, R.J. Yang, D. Zhou
KEK, Ibaraki, Japan

SuperKEKB has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} and aims at reaching a target luminosity of about 6 × 10³⁵ \si{cm^-2s^-1}. To accomplish this goal it is planned to increase beam currents up to §I{3.6}{A} and §I{2.6}{A} for the positron and the electron ring, respectively. Increasing the beam currents and, in particular, the number of leptons per bunch, can impact the optics parameters obtained by turn-by-turn measurements, such as the betatron tune or phase advance. Optics measurements performed at various bunch currents can give first indications of possible intensity dependent effects. In this paper, the effect of varying bunch current on optics measurements at SuperKEKB is explored.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB010

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 30 August 2021

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TUPAB011

Momentum Compaction Factor Measurements in the Large Hadron Collider

1360

J. Keintzel, L. Malina, R. Tomás García
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) at CERN and its planned luminosity upgrade, the High Luminosity LHC (HL-LHC) demand well-controlled on- and off-momentum optics. Optics measurements are performed by analysing Turn-by-Turn (TbT) data of excited beams. Different techniques to measure the momentum compaction factor from these data are explored, taking into account the possibility to combine them with RF-voltage scans in future experiments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB011

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paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021

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TUPAB013

A CLIC Dual Beam Delivery System for Two Interaction Regions

1364

V. Cilento, R. Tomás García
CERN, Geneva, Switzerland
A. Faus-Golfe
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

The Compact Linear Collider (CLIC) could provide e⁺e⁻ collisions in two detectors simultaneously possibly at a repetition frequency twice the design value. In this paper, a novel dual Beam Delivery System (BDS) design is presented including optics designs and the evaluation of luminosity performance with synchrotron radiation (SR) and solenoid effects for both energy stages of CLIC, 380 GeV and 3 TeV. In order to develop the novel optics design, parameters such as the longitudinal and the transverse detector separations were optimized. The luminosity performance of the novel CLIC scheme was evaluated by comparing the different BDS designs for both energy stages of CLIC. The dual CLIC BDS design provides a good luminosity and proves to be a viable candidate for future linear collider projects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB013

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021

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TUPAB015

Beam Loading Compensation of APS Cavity with Off-Crest Acceleration in ILC e-Driven Positron Source

1368

M. Kuriki, S. Konno, H. Nagoshi
HU/AdSM, Higashi-Hiroshima, Japan
T. Omori, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

In E-Driven positron source of ILC, the generated positron is captured by RF accelerator by APS cavity. The positron is initially placed at the deceleration phase and gradually slipped down to acceleration phase. Because the beam-loading is expected to be more than 1A with a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation is controlling the timing, but it doesn’t work in off-crest case. In this manuscript, we discuss the compensation with the phase and amplitude modulation on the input RF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB015

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021

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TUPAB016

ESS RFQ: Installation and Tuning at Lund

1372

P. Hamel, D. Chirpaz-Cerbat, M. Desmons, A.C. France, O. Piquet
CEA-IRFU, Gif-sur-Yvette, France
A. Dubois, Y. Le Noa
CEA-DRF-IRFU, France

The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019. It has been provided by CEA, IRFU, Saclay/France. It consists of five sections with a total length of 4.6 m and accelerates the 70 mA proton beam from 75 keV up to 3.6 MeV. It will be fed with 900 kW peak power through two coaxial loop couplers. The installation process (alignment, vacuum test), as well as the tuning process based on bead-pull measurements, is presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB016

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 14 August 2021

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TUPAB017

Study of Conduction-Cooled Superconducting Quadrupole Magnets Combined with Dipole Correctors for the ILC Main Linac

1375

Y. Arimoto, S. Michizono, Y. Morikawa, N. Ohuchi, T. Oki, H. Shimizu, K. Umemori, X. Wang, A. Yamamoto, Y. Yamamoto, Z.G. Zong
KEK, Ibaraki, Japan
V.S. Kashikhin
Fermilab, Batavia, Illinois, USA

A superconducting rf (SRF) cryomodule for International Linear Collider(ILC) Main Linac equips focus/steering magnets. The magnets are "superferric" magnets with four superconducting (SC) race track coils conductively cooled from the cryomodule LHe supply pipe. The quadrupole field gradient and dipole field are 40 T/m and 0.1 T, respectively. The magnet length and iron-pole radius are 1 m and 0.045 m, respectively. It is known that dark current is generated at SRF cavities and accelerated through the following linac string. The dark current reaches and heats the SC magnets. It is estimated that the power deposition in the magnet may reach more than a few watts and temperature of the SC coils may locally reach to critical temperature of NbTi. It is important to make the magnet not reach quench with sufficient conduction cooling. We aim to realize the SC magnet which can stably operate under such condition. We plan to develop test coils made of three types of SC materials, NbTi, Nb₃Sn, and MgB₂ and study thermal characteristics and stability . We will develop a short model magnet, based on the test coil results. Here, we will present the magnet design study and the R&D plan.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB017

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021

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TUPAB019

A High-Resolution, Low-Latency, Bunch-by-Bunch Feedback System for Nano-Beam Stabilization

1378

R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland
N. Blaskovic Kraljevic
ESS, Lund, Sweden
G.B. Christian
DLS, Oxfordshire, United Kingdom

A low-latency, bunch-by-bunch feedback system employing high-resolution cavity Beam Position Monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at the High Energy Accelerator Research Organization (KEK), Japan. The feedback system was designed to demonstrate nanometer-level vertical stabilization at the focal point of the ATF2 and can be operated using either a single BPM to provide local beam stabilization, or by using two BPMs to stabilize the beam at an intermediate location. The feedback correction is implemented using a stripline kicker and the feedback calculations are performed on a digital board constructed around a Field Programmable Gate Array (FPGA). The feedback performance was tested with trains of two bunches, separated by 280ns, at a charge of ~1nC, where the vertical offset of the first bunch was measured and used to calculate the correction to be applied to the second bunch. The BPMs have been demonstrated to achieve an operational resolution of ~20nm. With the application of single-BPM and two-BPM feedback, beam stabilization of below 50nm and 41nm respectively has been achieved with a latency of 232ns.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB019

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021

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TUPAB020

A Sub-Micron Resolution, Bunch-by-Bunch Beam Trajectory Feedback System and Its Application to Reducing Wakefield Effects in Single-Pass Beamlines

1382

D.R. Bett, P. Burrows, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland
K. Kubo, T. Okugi, N. Terunuma
KEK, Ibaraki, Japan

A high-precision intra-bunch-train beam orbit feedback correction system has been developed and tested at the KEK Accelerator Test Facility, ATF2. The system uses the vertical position of the bunch measured at two beam position monitors to calculate a pair of kicks which are applied to the next bunch using two upstream kickers, thereby correcting both the vertical position and trajectory angle. Using trains of two electron bunches separated in time by 187.6ns, the system was optimised so as to stabilize the beam offset at the feedback BPMs to better than 350nm, yielding a local trajectory angle correction to within 250nrad. The quality of the correction was verified using three downstream witness BPMs and the results were found to be in agreement with the predictions of a linear lattice model used to propagate the beam trajectory from the feedback region. This same model predicts a corrected be am jitter of c.1nm at the focal point of the accelerator. Measurements with a beam size monitor at this location demonstrate that reducing the trajectory jitter of the beam by a factor of 4 also reduces the increase in the measured beam size as a function of beam charge by a factor of ~1.6.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB020

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paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 11 August 2021

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TUPAB023

Design Considerations of a High Intensity Booster for PETRA IV

1386

H.C. Chao, I.V. Agapov, S.A. Antipovpresenter
DESY, Hamburg, Germany

A 6 GeV booster lattice with a high intensity capacity for the PETRA IV project is presented. Firstly the requirements and constraints are articulated. Due to the geometric constraints the ring will be installed in racks mounted on ceilings. Then following some design strategies of reaching high intensity limit, a lattice is designed and presented. The topics covering the linear optics, nonlinear dynamics, orbit correction, orbit bump, and some instability studies are investigated.

Poster TUPAB023 [0.975 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB023

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paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 12 August 2021

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TUPAB024

Lattice Options Comparison for a DLSR Injector

1390

H.C. Chao, I.V. Agapov, S.A. Antipovpresenter
DESY, Hamburg, Germany

DESY IV, as a part of the injector chain, must have lower emittance for PETRA IV injection. Depending on the scenarios of the injector, two lattice options for DESY IV are presented. They are designed for different purposes. The first option comes with a high momentum compaction factor with acceptable emittance. It is designed to be a full intensity booster. The other option is with low emittance dedicated to be an accumulator at high energies. The general beam dynamics properties are simulated and discussed. Their strengths and weaknesses are compared.

Poster TUPAB024 [0.751 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB024

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paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021

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TUPAB026

Application of Plasma Lenses as Optical Matching Device for Positron Sources at Linear Colliders

1394

M. Formela, N. Hamann, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
K. Flöttmann, G.A. Moortgat-Pick
DESY, Hamburg, Germany
S. Riemann
DESY Zeuthen, Zeuthen, Germany

Funding: Quantum Universe
In the baseline design of the International Linear Collider (ILC) an undulator-based positron source is foreseen. The proposed luminosity of the recently chosen first energy stage with √{s}=250 GeV requires an improvement by a factor of 2500 to the world’s first linear collider, the past SLC experiment. This ambitious luminosity goal can only be achieved, if all technological boundaries are being pushed. One such area is the captured positron number, which is primarily determined in the capture section within the positron source and specifically by its optical matching device. It is responsible for transforming the phase-space of the outgoing particles produced in the target for the succeeding accelerator sections. The plasma lens is a new candidate for this task. It being an especially adequate method due its magnetic field being azimuthal. Optimizing an idealised tapered active plasma lens for the ILC led us to a design with improved captured positron yield, outperforming ILC’s currently proposed quarter wave transformer by approximately 50%. The captured yield also proved to be stable within ±1.5% for deviations in design parameters of ±10%.

Poster TUPAB026 [0.293 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB026

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 24 August 2021

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TUPAB027

Review of Accelerator Limitations and Routes to Ultimate Beams

1397

F. Zimmermann
CERN, Geneva, Switzerland
R.W. Aßmann
DESY, Hamburg, Germany
M. Bai, G. Franchetti
GSI, Darmstadt, Germany

Funding: This work was supported in part by the European Commission under the HORIZON 2020 project I.FAST, no. 101004730.
Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. Possible figures-of-merit and pathways to ultimate colliders will also be explored.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB027

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paper received ※ 16 May 2021 paper accepted ※ 02 August 2021 issue date ※ 23 August 2021

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TUPAB028

Permanent Magnets Future Electron Ion Colliders at RHIC and LHeC

1401

D. Trbojevic, S.J. Brooks, V. Litvinenko, T. Roser
BNL, Upton, New York, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator.

Poster TUPAB028 [2.720 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB028

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paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 30 August 2021

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TUPAB030

Superb Fixed Field Permanent Magnet Proton Therapy Gantry

1405

D. Trbojevic, S.J. Brooks, T. Roser, N. Tsoupas
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We present the top notch design of the proton therapy gantry made of permanent magnets with very strong focusing. This represents a superb solution fulfilling all cancer treatment requirements for all energies without changing any parameters. The proton energy range is between 60-250 MeV. The beam arrives to the patient focused at each required treatment energy. The scanning system is place between the end of the gantry and the patient. There are multiple advantages of this design: easy operation, no significant electrical power - just for the correction system, low weight, low cost. The design is based on the recent very successful commissioning of the permanent magnet ERL ’CBETA’ at Cornell University.

Poster TUPAB030 [7.816 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB030

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paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 21 August 2021

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TUPAB031

Construction and Installation of the New CERN Proton Synchrotron Internal Beam Dumps

1409

K.G. Andersen, M. Calviani, A. Cherif, T. Coiffet, A. De Macedo, S. Devidal, J.-M. Geisser, S.S. Gilardoni, M.M.J. Gillet, E. Grenier-Boley, J.M. Herediapresenter, A. Majbour, F. Monnet, M.R. Monteserin, F.-X. Nuiry, D. Pugnat, G. Romagnoli, Y.D.R. Seraphin, J.A.F. Somoza, N. Thaus
CERN, Geneva 23, Switzerland

In the framework of the CERN Large Hadron Collider Injectors Upgrade (LIU) Project, the Proton Synchrotron (PS) has been equipped with two new movable Internal Dumps (PSID), each of them capable of absorbing particle beams of an energy of up to 100 kJ. These dumps replace the old Internal Dumps, which have been operated in the accelerator complex since their installation in 1975 until their decommissioning and removal from the machine during the second LHC Long Shut down (LS2). This contribution will address the construction and testing phases of the new PSIDs, including the assembly of the dump core, its actuation system and the respective shielding, mechanical running-in tests, metrology adjustments, Ultra-High Vacuum (UHV) and impedance acceptance tests. The described installation work was completed successfully, and the new generation Dumps are currently operational in the PS machine.

Poster TUPAB031 [3.146 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB031

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paper received ※ 18 May 2021 paper accepted ※ 27 May 2021 issue date ※ 26 August 2021

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TUPAB033

Photocathode Stress Test Bench at INFN LASA

1413

D. Sertore, D. Giove, G. Guerini Rocco, L. Monaco
INFN/LASA, Segrate (MI), Italy
A. Bacci, F. Canella, S. Cialdi, I. Drebot, D. Giannotti, L. Serafini
INFN-Milano, Milano, Italy
D. Cipriani, E. Suerra
Università degli Studi di Milano, Milano, Italy
G. Galzerano
POLIMI, Milano, Italy

In the framework of the preparatory activities to the BriXSino project, a test bench for testing Cs₂Te photocathode at 100 MHz laser repetition rate has been installed at INFN LASA. This high repetition operation mode is foreseen to be the base operation mode of BriXSino and a qualification of the Cs₂Te photocathodes is a key component. While we are not at full specification due to the limited HV of the present DC gun, we discuss the status of the test bench and the initial results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB033

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 19 August 2021

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TUPAB034

Development of Multi-Alkali Antimonides Photocathodes for High-Brightness RF Photoinjectors

1416

S.K. Mohanty, M. Krasilnikov, A. Oppelt, H.J. Qian, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Guerini Rocco, C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy

Multi-alkali antimonide-based photocathodes are suitable candidate for the electron sources of next-generation high brightness RF photoinjectors due to their excellent photoemissive properties especially, like low thermal emittances and high sensitivity to visible light. The former stands out, paving the way towards CW operations. Based on the previous successful development of Cesium Telluride photocathodes, we are now channelling our efforts toward an R&D activity focused on KCsSb and NaKSb(Cs) photocathodes. Parallel to that R&D activity, we have installed a new dedicated photocathode production system at the INFN-LASA to start the preparation of these photocathodes for their test in the PITZ photoinjector at DESY in Zeuthen. In this paper, detailed experimental results obtained from the KCsSb, along with a preliminary result from the NaKSb(Cs) photocathode material as well as the status of the overall project are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB034

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 31 August 2021

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TUPAB035

ESS Medium Beta Cavities Status at INFN LASA

1420

D. Sertore, M. Bertucci, M. Bonezzi, A. Bosotti, A. D’Ambros, A.T. Grimaldi, P. Michelato, L. Monaco, R. Paparella
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

INFN Milano contributes in-kind to the ESS ERIC Superconducting Linac supplying 36 cavities for the Medium Beta section of the proton accelerator. The production has reached completion, being all the cavities mechanical fabricated, BCP treated and, for most of them, also qualified with vertical test at cold. In this paper, we report on the results and lessons learnt and the actions taken both for quality control managing and recovery of the few cavities that did not reach the project goal after the first qualification test.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB035

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 18 August 2021

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TUPAB036

The Accelerator Design Progress for EIC Strong Hadron Cooling

1424

E. Wang, S. Peggs, V. Ptitsyn, F.J. Willeke, W. Xu
BNL, Upton, New York, USA
S.V. Benson
JLab, Newport News, Virginia, USA
D. Douglas
Douglas Consulting, York, Virginia, USA
C.M. Gulliford, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
Xelera Research LLC, Ithaca, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy,
The Electron-Ion Collider will achieve a luminosity of 10³⁴ cm^-2 s⁻¹ by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB036

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paper received ※ 16 May 2021 paper accepted ※ 11 June 2021 issue date ※ 01 September 2021

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TUPAB037

The Design of a High Charge Polarized Preinjector for the Electron-Ion Collider

1428

E. Wang, W. Liu, V.H. Ranjbar, J. Skaritka, N. Tsoupas
BNL, Upton, New York, USA
J.M. Grames, J. Guo
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The design of the electron pre-injector of the Electron-Ion Collider (EIC) project to generate 4 x 7 nC bunch has been advancing to meet the requirements for injection into the Rapid Cycling Synchrotron (RCS). The major challenges are high charge transport and achieving small energy spread from 3 GHz traveling-wave plate(TWP). The designed preinjector includes the polarized electron source, bunching section, TWP Linac, zigzag phase space manipulation and spin rotator. In this report, we will discuss the RF frequency selection and the way to reduce energy spread down to 0.2% by longitudinal phase space manipulate. We will also report the results of beamline simulation using space charge code and the conceptual design of spin rotator.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB037

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paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 27 August 2021

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TUPAB038

Simulation of the Filling Pattern Dependent Regenerative Beam Breakup Instabilities in Energy Recover Linacs

1431

S. Setiniyaz, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The interaction of a transversely displaced beam with the higher modes (HOM) of the accelerating cavities causes building up HOM voltages in the cavity, which in turn kicks the beam and increases the offset further. This is known as regenerative beam breakup (BBU) instability and it sets the beam threshold current for the stable beam operation. A study by Setiniyaz et al.~[Setiniyaz2020] showed the filling pattern and recombination schemes of multi-turn energy recovery linacs (ERLs) can create many different beam loading transients, which can have a big impact on the cavity fundamental mode voltage and RF stabilizes. In this work, we extend the study of the filling pattern and recombination schemes to the BBU instabilities and threshold current. In the ERLs, the accelerated and decelerated bunches can be ordered differently while they pass through the cavity and form different filling patterns. Each pattern has a unique bunch energy sequence and bunch arrival times and hence interacts with cavity uniquely and thus drives BBU differently. In this paper, we introduce a simulation tool to investigate the filling pattern dependence of the ERL BBU instability.
* S. Setiniyaz, R. Apsimon, and P. H. Williams, Phys. Rev. Accel. Beams 23, 072002, 2020.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB038

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paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 15 August 2021

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TUPAB040

Design Concept for the Second Interaction Region for Electron-Ion Collider

1435

B.R. Gamage, V. Burkert, R. Ent, Y. Furletova, D.W. Higinbotham, A. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, D. Romanov, T. Satogata, A. Seryi, A.V. Sy, C. Weiss, M. Wiseman, W. Wittmer, Y. Zhang
JLab, Newport News, Virginia, USA
E.C. Aschenauer, J.S. Berg, A. Jentsch, A. Kiselev, C. Montag, R.B. Palmer, B. Parker, V. Ptitsyn, F.J. Willeke, H. Witte
BNL, Upton, New York, USA
C. Hyde
ODU, Norfolk, Virginia, USA
P. Nadel-Turonski
SBU, Stony Brook, New York, USA

Funding: Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 and Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The possibility of two interaction regions (IRs) is a design requirement for Electron-Ion Collider (EIC). There is also a significant interest from the nuclear physics community to have a 2nd IR with measurement capabilities complementary to those of the 1st IR. While the 2nd IR will be in operation over the entire energy range of ~20GeV to ~140GeV center of mass (CM). The 2nd IR can also provide an acceptance coverage complementary to that of the 1st. In this paper, we present a brief overview and the current progress of the 2nd IR design in terms of the parameters, magnet layout, and beam dynamics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB040

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paper received ※ 24 May 2021 paper accepted ※ 31 August 2021 issue date ※ 30 August 2021

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TUPAB041

Detector Solenoid Compensation for the Electron-Ion Collider

1439

B.R. Gamage, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, A. Seryi, W. Wittmer, Y. Zhang
JLab, Newport News, Virginia, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
A. Kiselev, H. Lovelace III, B. Parker, S. Peggs, S. Tepikian, F.J. Willeke, H. Witte, Q. Wu
BNL, Upton, New York, USA

Funding: Jefferson Science Associates, LLC Contract No. DE-AC05-06OR23177, Fermi Research Alliance, LLC Contract No. DE-AC02-07CH11359, and Brookhaven Science Associates, LLC Contract No. DE-SC0012704
The central detector in the present EIC design includes a 4 m long solenoid with an integrated strength of up to 12 Tm. The electron beam passes on-axis through the solenoid, but the hadron beam has an angle of 25 mrad. Thus the solenoid couples horizontal and vertical betatron motion in both electron and hadron storage rings, and causes a vertical closed orbit excursion in the hadron ring. The solenoid also couples the transverse and longitudinal motions of both beams, when crab cavities are also considered. In this paper, we present schemes for closed orbit correction and coupling compensation at the IP, including crabbing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB041

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paper received ※ 28 May 2021 paper accepted ※ 31 August 2021 issue date ※ 12 August 2021

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TUPAB042

Large Radial Shifts in the EIC Hadron Storage Ring

1443

S. Peggs, J.S. Berg, K.A. Drees, X. Gu, C. Liu, H. Lovelace III, Y. Luo, G.J. Marr, A. Marusic, F. Méot, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, M. Valette, S. Verdú-Andrés
BNL, Upton, New York, USA
K.E. Deitrick
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
B.R. Gamage
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Electron Ion Collider will collide hadrons in the Hadron Storage Ring (HSR) with ultra-relativistic electrons in the Electron Storage Ring. The HSR design trajectory includes a large radial shift over a large fraction of its circumference, in order to adjust the hadron path length to synchronize collisions over a broad range of hadron energies. The design trajectory goes on-axis through the magnets, crab cavities and other components in the six HSR Insertion Regions. This paper discusses the issues involved and reports on past and future beam experiments in the Relativistic Heavy Ion Collider, which will be upgraded to become the HSR.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB042

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021

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TUPAB044

Preliminary Study of the on-Axis Swap-Out Injection Scheme for the Southern Advanced Photon Source

1447

Y. Han, X.H. Lu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Huang, Y. Jiao, X. Liupresenter, S. Wang
IHEP, Beijing, People’s Republic of China

The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. The extremely low emittance will result in a very small dynamic aperture for the storage ring which makes it difficult to use the conventional off-axis accumulation injection. In this case, it is probably necessary to consider the transverse on-axis injection or the longitudinal injection. In this paper, the transverse on-axis swap-out injection scheme for the SAPS storage ring is presented. The preliminary parameters of the septum magnets and fast kickers are carefully evaluated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB044

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paper received ※ 17 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB045

The Low Energy Injector Design for the Southern Advanced Photon Source

1450

Y. Han
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, B. Li, X. Liupresenter, S. Wang
IHEP, Beijing, People’s Republic of China

The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. At present, two injector options are under consideration. One is a full energy booster plus a low energy injector, and another is a full energy linac injector. In this paper, a preliminary design of the low energy injector is presented, which consists of an DC thermionic electron gun, a bunching section and an accelerating section. The beam energy at the end of the injector is about 150 MeV.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB045

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 18 August 2021

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TUPAB046

Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source

1454

X. Liu
Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China
Y. Jiao, B. Li, S. Wang
IHEP, Beijing, People’s Republic of China

A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021

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TUPAB047

Bunch Compressor Design in the Full Energy Linac Injector for the Southern Advanced Photon Source

1458

B. Li
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, X. Liupresenter, S. Wang
IHEP, Beijing, People’s Republic of China

A mid-energy fourth-generation storage ring light source named the Southern Advanced Photon Source (SAPS), has been considered to be built neighboring the China Spallation Neutron Source (CSNS). A full energy linac has been proposed as an injector to the storage ring, with the capability to generate high brightness electron beams to feed a Free Electron Laser (FEL) at a later stage. To achieve the high peak current in FELs, space charge, RF structure wakefield, coherent synchrotron radiation (CSR), RF curvature, and the second-order momentum compaction factor should be carefully considered and optimized during the bunch compression processes. In this paper, physic design and simulation results of the bunch compressors are described.

Poster TUPAB047 [1.918 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB047

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paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 28 August 2021

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TUPAB048

HMBA Optics Correction Experience at ESRF

1462

S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Farvacque, T.P. Perron, P. Raimondi, S.M. White
ESRF, Grenoble, France

The ESRF-EBS storage ring, successfully commissioned in 2020, operates the HMBA lattice, first proposed in * and then adopted in several recent upgrade programs. The successful and timely commissioning of the storage is in large part due to the excellent optics control achieved over that period. Design performance were obtained with lower than predicted correction strengths, localized for the most part in the vicinity of sextupoles. This remarkable behavior is not only the result of the corrective actions taken during the commissioning but also of the extremely accurate conception and alignment of the machine. This report summarizes the steps that lead to the present performances and discusses their stability over time.
* J.Biasci et al. Synchrotron Radiation News27, 8 (2014), https://doi.org/10.1080/08940886.2014.970931.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB048

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paper received ※ 10 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021

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TUPAB049

USSR HMBA Storage Ring Lattice Options

1466

S.M. Liuzzo, N. Carmignani, L.R. Carver, J. Chavanne, L. Hoummi, J. Jacob, T.P. Perron, R. Versteegen, S.M. White
ESRF, Grenoble, France
I.A. Ashanin, V.S. Dyubkov, S.M. Polozov
MEPhI, Moscow, Russia
I.A. Ashanin, V.S. Dyubkov, T. Kulevoy, S.M. Polozov
NRC, Moscow, Russia
T. Kulevoy
ITEP, Moscow, Russia

Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution #287
Several new accelerator facilities will be built in Russia in a few years from now. One of those facilities is a 6GeV storage ring (SR) light source (USSR - Ultimate Source of Synchrotron Radiation) to be built in Protvino, near Moscow. The Cremlin+ project aims to incorporate in this activity the best experience of European Accelerator Laboratories. The design of the optics for this SR is presented here in two declinations leading to 70 pm-rad equilibrium horizontal emittance. The first is a 40 cells lattice, the second is the same but includes high field Short Bending magnet sources in each cell. Optics and high order multipole optimizations are performed to obtain sufficient lifetime and dynamic aperture for a conservative off-axis injection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB049

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paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021

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TUPAB050

A Long Booster Option for the USSR 6 GeV Storage Ring

1470

S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Hoummi, T.P. Perron, R. Versteegen, S.M. White
ESRF, Grenoble, France
I.A. Ashanin, S.M. Polozov
MEPhI, Moscow, Russia
I.A. Ashanin, T. Kulevoy, S.M. Polozov
NRC, Moscow, Russia
T. Kulevoy
ITEP, Moscow, Russia

Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution no. 287
The design of the optics of a full length 6 GeV booster for the USSR (Ultimate Source of Synchrotron Radiation) are presented. This option already followed with success by other laboratories, would allow to obtain a small emittance injected beam thus enabling smooth top-up operation. Details of the design inspired by the ESRF DBA lattice and the possible operating modes are described. The transfer lines booster to storage ring are also addressed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB050

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paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 24 August 2021

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TUPAB051

Elettra and Elettra 2.0

1474

E. Karantzoulis, A. Carniel, D. Castronovo, S. Di Mitri, B. Diviacco, S. Krecic
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with the future upgrade concerning the new ultra-low emittance light source Elettra 2.0 that will provide ultra-high brilliance while the very short pulses feasibility study for time resolved experiments is in progress.

Poster TUPAB051 [1.632 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB051

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paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 20 August 2021

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TUPAB052

Current Study of Applying Machine Learning to Accelerator Physics at IHEP

1477

J. Wan, Y. Jiao
IHEP, Beijing, People’s Republic of China

Funding: National Natural Science Foundation of China(No.11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904) and National Key R&D Program of China(No.2016YFA0401900).
In recent years, machine learning (ML) has attracted increasing interest among the accelerator field. As a complex collection of multiple physical subsystems, the design and operation of an accelerator can be very nonlinear and complicated, while ML is taken as a powerful tool to solve such nonlinear and complicated problems. In this study, we report on several successful applications of ML to accelerator physics at IHEP. The nonlinear dynamics optimization of the High Energy Photon Source (HEPS) that is a 4th-generation light source is a challenging topic. In this optimization, we use a ML surrogate model to fast select the potentially competitive solutions for a multiobjective genetic algorithm that can significantly improve the convergence rate and the diversity among obtained solutions. Besides, we also tried to apply a generative adversarial net to solve one-to-many problems of longitudinal beam current profile shaping. Unlike most supervised machine learning methods than cannot learn one-to-many maps, the generative adversarial net-based method is able to predict multiple solutions instead of one for a 4-dipole chicane to realize several desired custom current profiles.

Poster TUPAB052 [0.913 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB052

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paper received ※ 11 May 2021 paper accepted ※ 21 June 2021 issue date ※ 27 August 2021

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TUPAB053

Design Progress of ALS-U 3rd-Harmonic Cavity

1481

T.H. Luo, K.M. Baptiste, S. De Santis, D. Li, J.W. Staples, M. Venturini
LBNL, Berkeley, California, USA
H.Q. Feng
TUB, Beijing, People’s Republic of China

Funding: Director, Office of Science, Office of Basic Energy Sciences, and LDRD Program of Lawrence Berkeley National Laboratory, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
A higher-harmonic rf cavity (HHC) system is required in the ALS-U storage ring to lengthen the bunches, reduce intrabeam-scattering effects, and improve Touschek beam lifetime. A 3rd harmonic, normal conducting, passive-cavity system has been chosen based on beam-dynamics requirements and cost considerations. We have explored two options for ALS-U 3HC system: a high-R/Q re-entrant cavity with waveguide HOM dampers, and a low-R/Q system with two elliptical cavities and HOM beam line absorbers. In this paper, we present the recent progress on the cavity design and related beam dynamics studies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB053

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paper received ※ 19 May 2021 paper accepted ※ 11 June 2021 issue date ※ 14 August 2021

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TUPAB054

CDR BASELINE LATTICE FOR THE UPGRADE OF SOLEIL

1485

A. Loulergue, D. Amorim, P. Brunelle, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous MBA studies converged toward a lattice composed of 20 7BA solution elaborated by adopting the sextupole pairing scheme with dispersion bumps originally developed at the ESRF-EBS. It provided a low natural horizontal emittance value of 70-80 pm-rad range at an energy of 2.75 GeV. Due to difficulties to accommodate such lattice geometry in the SOLEIL present tunnel as well as to preserve at best the beamline positioning, alternative lattice based on HOA (Higher-Order Achromat) type cell has been recently investigated. The HOA type cell being more modular and possibly exhibiting larger momentum acceptance as well as low emittances, a solution alternating 7BA and 4BA cells was then identified as the best to adapt the current beamline positioning. The SOLEIL CDR upgrade reference lattice is then composed of 20 HOA cells alternating 7BA and 4BA giving a natural horizontal emittance of 80 pm-rad. The linear and non-linear beam dynamic properties of the lattice along with the possibility of horizontal off-axis injection at full betatron coupling are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB054

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paper received ※ 21 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021

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TUPAB057

Carbon Beam at I-3 Injector for Semiconductor Implantation

1489

A.A. Losev, P.N. Alekseev, N.N. Alexeev, T. Kulevoypresenter, A.D. Milyachenko, Yu.A. Satov, A. Shumshurov
ITEP, Moscow, Russia
P.B. Lagov
NUST MISIS, Moscow, Russia
M.E. Letovaltseva
MIREA, Moscow, Russia
Y.S. Pavlov
IPCE RAS, Moscow, Russia

Carbon implantation can be effectively used for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures. When carbon is implanted, more stable recombination centers are formed and silicon is not doped with additional impurities, as for example, when irradiated with protons or helium ions. Economically, such a process competes with alternative methods, and is more efficient for obtaining small lifetimes (several nanoseconds). I-3 ion injector with laser-plasma ion source in Institute for theoretical and experimental physics (ITEP) is used as ion implanter in semiconductors. The ion source uses pulsed CO₂ laser setup with radiation-flux density of 10¹¹ W/cm² at target surface. The ion source produces beams of various ions from solid targets. The generated ion beam is accelerated in the two gap RF resonator at voltage of up to 2 MV per gap. Resulting beam energy is up to 4 MV per charge. Parameters of carbon ion beam generated and used for semiconductor samples irradiation during experiments for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures are presented.

Poster TUPAB057 [0.630 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB057

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paper received ※ 15 May 2021 paper accepted ※ 28 May 2021 issue date ※ 01 September 2021

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TUPAB058

Online Optimizations of Several Observable Parameters at the Advanced Photon Source

1492

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Online optimizations are known to be powerful tools which may quickly and efficiently improve the particle accelerator key performance parameters in a model-independent way. In this paper, it is presented on the online optimizations of several observable parameters at the Advanced Photon Source storage ring. These observable parameters include the beam lifetime, injection efficiency and topup efficiency, transverse beam sizes, and turn by turn beam position monitors. It is demonstrated that the particle accelerator performance may be greatly enhanced in a relatively short time frame, by optimizing these observable parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB058

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 16 August 2021

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TUPAB059

Measurement of the Advanced Photon Source Lifetime at Different Level of Beta-Beating

1496

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Linear optics correction of a particle accelerator may not be perfect due to the existence of different errors sources in response matrix measurements and optics correction process. Previous numerical simulation study has shown that the single particle beam dynamics performance may be highly correlated with the level of residual beta-beating. In this paper, the machine study results on beam lifetime of the APS storage ring is presented. The experiment is performed at different level of predefined beta-beating with negligible betatron tunes variations. As expected, the measured beam lifetime has an inverse correlation with the level of beta-beating.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB059

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 16 August 2021

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TUPAB060

Machine Learning on Beam Lifetime and Top-Up Efficiency

1499

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Both unsupervised and supervised machine learning techniques are employed for automatic clustering, modeling and prediction of Advanced Photon Source (APS) storage ring beam lifetime and top-up efficiency archived in operations. The naive Bayes classifier algorithm is developed and combined with k-means clustering to improve accuracy, where the unsupervised clustering of APS beam lifetime and top-up efficiency is consistent with either true label from data archive or Gaussian kernel density estimation. Artificial neural network algorithms have been developed, and employed for training and modelling the arbitrary relations of beam lifetime and top-up efficiency on many observable parameters. The predictions from artificial neural network reasonably agree with the APS operation data.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB060

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paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021

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TUPAB061

Anomaly Detection by Principal Component Analysis and Autoencoder Approach

1502

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Several different approach are employed to identify the abnormal events in some Advanced Photon Source (APS) operation archived dataset, where dimensionality reduction are performed by either principal component analysis or autoencoder artificial neural network. It is observed that the APS stored beam dump event, which is triggered by magnet power supply fault, may be predicted by analyzing the magnets capacitor temperatures dataset. There is reasonable agreement among two principal component analysis based approaches and the autoencoder artificial neural network approach, on predicting future overall system fault which may result in a stored beam dump in the APS storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB061

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paper received ※ 22 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021

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TUPAB062

Expediting APS-U Long-Term Particle Tracking with Arbitrary Order Taylor Map

1505

Y.P. Sun
ANL, Lemont, Illinois, USA

Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Truncated power series algebra was integrated within explicit symplectic integration to formulate an arbitrary order multivariate Taylor map for any given particle accelerator lattice. Tracking simulation performed with these Taylor maps shows good long term stability and physics accuracy. There is good agreement in long term particle tracking simulations between Taylor map and element by element tracking of APS-U lattice, when the particle is within 1 to 10 σ of stored beam. It is demonstrated that most of the lower order resonance driving terms, plus chromatic and geometric aberrations are reasonably preserved by the Taylor map approach. Last but maybe most important, the computation time is reduced by a factor of 20 to 50, when compared to symplectic integration based element by element tracking.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB062

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 29 August 2021

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TUPAB063

Study of PF-Ring Infrastructure Improvements Using Temperature Measurements in the Ring Tunnel

1508

N. Nakamura, K. Haga, T. Nogami, M. Tadano
KEK, Ibaraki, Japan

Temperature measurements have been performed in the PF-ring tunnel in order to understand the infrastructure performance and the temperature stability towards the PF upgrade project, where better beam stability will be required. Based on the temperature measurements, possible improvements of the PF-ring infrastructure such as an air-conditioning system have been studied to enhance the temperature stability in the PF-ring tunnel. In this paper, we present results of the temperature measurements in the PF-ring tunnel and a proposal of the PF-ring infrastructure improvements for the temperature stabilization.

Poster TUPAB063 [6.169 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB063

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paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021

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TUPAB064

Specifications and Performance of a Chicane Magnet for the cERL IR-FEL

1512

N. Nakamura, K. Harada, N. Higashi, Y. Honda, R. Kato, C. Mitsuda, S. Nagahashi, T. Obina, H. Sakai, M. Shimada, H. Takaki, O.A. Tanaka
KEK, Ibaraki, Japan
Y. Lu
Sokendai, Ibaraki, Japan

Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)".
The IR-FEL was constructed in the Compact ERL (cERL) at KEK from October 2019 to May 2020 for the purpose of developing high-power mid-infrared lasers for high-efficiency laser processing utilizing molecular vibrational absorption. The chicane magnet was newly installed between two IR-FEL undulators in the cERL in order to increase the FEL gain and pulse energy by converting the energy modulation to the density modulation in an electron bunch. It consists of three dipole magnets with laminated yokes made of 0.1-mm-thick permalloy sheets and the coil currents of the three magnets are independently controlled by three power supplies with the maximum current of 10 A. The maximum closed orbit bump made by the chicane magnetic field has the longitudinal dispersion(R56) of -6 mm. The coil-current ratio of the three dipole magnets was tuned after installation to make its orbit bumps closed and then the chicane magnet was used in the FEL operation. We present specifications and operational performance of the chicane magnet.

Poster TUPAB064 [4.053 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB064

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paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 25 August 2021

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TUPAB065

Solaris Storage Ring Performance After 6 Years of Operation

1515

A.I. Wawrzyniak, A. Curcio, K. Gula, M.A. Knafel, G.W. Kowalski, A.M. Marendziak, R. Panaś, M. Waniczek, M. Wiśniowski
NSRC SOLARIS, Kraków, Poland

Solaris is a third generation light source operating since 2015 in Kraków, Poland. Between 2015 and 2018 the synchrotron as well as two beamlines were commissioned. During commissioning phases, the good performance of Solaris storage ring has been reached. The beam optics was brought close to the design one. Since October 2018 Solaris storage ring is in the user operation mode. Moreover, two other beamlines with the elliptically polarized undulators used as source were installed and are under commissioning now. In 2020 the total beam availability of 93% was reached with the average circulating current of 400 mA and the total lifetime of 15 h. Over last two years few improvements of the storage ring were done to optimize the storage ring performance. The Landau cavities were tuned to improve the Touschek lifetime and suppress the instabilities. Two diagnostics beamlines were installed and commissioned allowing for the beam sizes in three planes and emittance measurements. The storage ring optics was fine-tuned to increase the dynamic aperture.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB065

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paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021

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TUPAB066

Status of the Short-Pulse Source at DELTA

1518

A. Held, B. Büsing, H. Kaiser, S. Khan, D. Krieg, A.R. Krishnan, C. Mai
DELTA, Dortmund, Germany

Funding: Work supported by BMBF (05K19PEB).
At the synchrotron light source DELTA operated by the TU Dortmund University, the short-pulse source employs the seeding scheme coherent harmonic generation (CHG) and provides ultrashort pulses in the vacuum ultraviolet and terahertz regime. Here, the interaction of laser pulses with the stored electron bunches result in a modulation of the longitudinal electron density which gives rise to coherent emission at harmonics of the laser wavelength. Recently, investigations of the influence of the Gouy phase shift at the focal point of the laser pulses on the laser-electron interaction have been performed. For the planned upgrade towards the more sophisticated seeding scheme echo-enabled harmonic generation (EEHG) featuring a twofold laser-electron interaction, simulations of the ideal parameters of the laser beams have been carried out.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB066

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 28 August 2021

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TUPAB067

Production of 120 MeV Gamma-ray Beams at Duke FEL and HIGS Facility

1522

S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, Y.K. Wu, J. Yan
FEL/Duke University, Durham, North Carolina, USA
M.W. Ahmed, M. Sikora
TUNL, Durham, North Carolina, USA
H. Ehlers, L.O. Jensen, L. Kochanneck
Laser Zentrum Hannover, Hannover, Germany

Funding: This work is supported by the US DoE grant #DE-FG02-97ER41033
In this paper we report extension of the operational energy of the gamma ray beams produced at Duke High Intensity Gamma-ray Source (HIGS) up to ~120MeV, opening up a new high energy region of gamma rays for photonuclear physics research. This achievement is based upon development of radiation robust, thermally stable, high-reflectivity fluoride (LaF3/MgF2) multilayer VUV FEL mirrors, enabling us to maintain stable high intensity FEL lasing at the wavelengths of around 175nm. We discuss the challenges of HIGS operation at high gamma and high electron beam energies with the downstream FEL mirror exposed to extremely hush radiation. The experience of the first HIGS user operation with high intensity, high gamma-ray beam energies (85 and ~120MeV) using these new mirrors is also discussed.

Poster TUPAB067 [1.023 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB067

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paper received ※ 30 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021

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TUPAB069

The Sabina Terahertz/Infrared Beamline at SPARC-Lab Facility

1525

S. Macis
La Sapienza University of Rome, Rome, Italy
M. Bellaveglia, M. Cestelli Guidi, E. Chiadroni, F. Dipace, A. Ghigo, L. Giannessi, A. Giribono, L. Sabbatini, C. Vaccarezza
INFN/LNF, Frascati, Italy
A. Doria, A. Petralia
ENEA C.R. Frascati, Frascati (Roma), Italy
S. Lupi
Sapienza University of Rome, Roma, Italy
V. Petrillo
INFN-Milano, Milano, Italy

Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program.
Following the EU Terahertz (THz) Road Map*, high-intensity, ps-long, THz)/Infrared (IR) radiation is going to become a fundamental spectroscopy tool for probing and control low-energy quantum systems ranging from graphene, and Topological Insulators, to novel superconductors** ***. In the framework of the SABINA project, a novel THz/IR beamline based on an APPLE-X undulator emission will be developed at the SPARC-Lab facility at LNF-INFN. Light will be propagated from the SPARC-Lab to a new user lab facility nearly 20 m far away. This beamline will cover a broad spectral region from 3 THz to 30 THz, showing ps- pulses and energy of tens of µJ with variable polarization from linear to circular. The corresponding electric fields up to 10 MV/cm, are able to induce non-linear phenomena in many quantum systems. The beamline, open to user experiments, will be equipped with a 5 T magnetic cryostat and will be synchronized with a fs laser for THz/IR pump, VIS/UV probe experiments.
[*] S.S. Dhillon et al., J. Phys. D: Appl. Phys. 50, 043001 (2017);
[**] F. Giorgianni et al., Nature Commun. 7, 11421 (2016);
[***] P. Di Pietro et al., Phys. Rev. Lett. 124, 226403 (2020);

Poster TUPAB069 [0.884 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB069

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paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021

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TUPAB071

Beam Line Design and Instrumentation for THz@PITZ - the Proof-of-Principle Experiment on a THz SASE FEL at the PITZ Facility

1528

T. Weilbach, P. Boonpornprasert, G.Z. Georgiev, G. Koss, M. Krasilnikov, X. Li, A. Lueangaramwong, F. Mueller, A. Oppelt, S. Philipp, F. Stephan, L.V. Vu
DESY Zeuthen, Zeuthen, Germany
H. Shaker
CLS, Saskatoon, Saskatchewan, Canada

In order to allow THz pump-X-ray probe experiments at full bunch repetition rate for users at the European XFEL, the Photo Injector Test Facility at DESY in Zeuthen (PITZ) is building a prototype of an accelerator-based THz source. The goal is to generate THz SASE FEL radiation with a mJ energy level per bunch using an LCLS-I undulator driven by the electron beam from PITZ. Therefore, the existing PITZ beam line is extended into a tunnel annex downstream of the existing accelerator tunnel. The beam line extension in the PITZ tunnel consists of three quadrupole magnets, a bunch compressor, a collimation system and a beam dump. In the second tunnel a dipole magnet allows to serve two beam lines, one of them the THz@PITZ beam line. It consists of one LCLS-I undulator for the production of the THz radiation, a quadrupole triplet in front of it and a quadrupole doublet behind it. For the electron beam diagnostic six new screen stations are built, three of them also allow for the observation of the THz radiation for measurements. In addition six BPMs and a new BLM system for machine protection and FEL gain curve measurement will be installed. The progress of this work will be presented.

Poster TUPAB071 [1.978 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB071

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paper received ※ 18 May 2021 paper accepted ※ 14 June 2021 issue date ※ 13 August 2021

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TUPAB072

The Status of a Grating Monochromator for Soft X-Ray Self-Seeding Experiment at SHINE

1532

K.Q. Zhang
SSRF, Shanghai, People’s Republic of China
H.X. Deng, C. Feng, B. Liu, T. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

The research status of a grating monochromator for soft X-ray self-seeding experiment at SHINE has been presented in this paper. The monochromator system includes the vacuum cavity, optical elements, and mechanical movement devices. Until now, the vacuum cavity has finished the manufactured process completely, the optical mirrors have finished machining and measured by the longitudinal trace profiler (LTP) and atomic force microscope (AFM). To make sure the monochromator system can achieve an optical resolution of 1/10000 at the photon energy of 700-1300eV, the system has been integrated and tested recently. In this year, the previous online experiment will be performed in the shanghai soft X-ray free-electron laser (FEL) user facility.

Poster TUPAB072 [0.717 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB072

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paper received ※ 11 May 2021 paper accepted ※ 09 June 2021 issue date ※ 01 September 2021

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TUPAB073

The Design of EEHG Cascaded Harmonic Lasing for SXFEL User Facility

1536

K.Q. Zhang, C. Feng
SSRF, Shanghai, People’s Republic of China
H.X. Deng, B. Liu, T. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

The preliminary design and simulation results of EEHG cascaded harmonic lasing for the SXFEL user facility have been presented in this paper. Using the basic seeded beamline of the SXFEL user facility, the designed parameters are optimized to obtain full coherent FEL output at the 90th harmonic of a 265 nm seed laser. According to the designed parameters and the layout of the SXFEL user facility, the detailed simulations are carried out, the results show that the seeded beamline of the SXFEL user facility can generate 2.93 nm full coherent radiation by the proposed method, which indicates that the method can extend the photon energy range of a seeded FEL and the method can be achieved at the SXFEL user facility.

Poster TUPAB073 [0.955 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB073

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paper received ※ 11 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB074

S-Band Transverse Deflecting Structure Design for CompactLight

1540

X.W. Wu, W. Wuensch
CERN, Meyrin, Switzerland
S. Di Mitri
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
N. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, which is based on high-gradient X-band (12 GHz) structures. However, to carry out pump-and-probe experiments in the project, two-bunch operation with a spacing of 10 X-band rf cycles is proposed. A sub-harmonic transverse deflecting structure working at S-band is proposed to direct the two bunches into two separate FEL lines. The two FEL pulses will have independently tunable wavelengths and can be combined in a single experiment with a temporal delay between pulses of ± 100 fs. The rf design of the transverse deflector is presented in this paper.

Poster TUPAB074 [1.557 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB074

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 21 August 2021

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TUPAB076

High-Gradient Breakdown Studies of an X-Band Accelerating Structure Operated in the Reversed Taper Direction

1543

X.W. Wu, N. Catalán Lasheras, A. Grudiev, G. McMonagle, I. Syratchev, W. Wuensch
CERN, Meyrin, Switzerland
M. Boronat
IFIC, Valencia, Spain
A. Castilla, A.V. Edwards, W.L. Millar
Lancaster University, Lancaster, United Kingdom

The results of high-gradient tests of a tapered X-band traveling-wave accelerator structure powered in reversed direction are presented. Powering the tapered structure from the small aperture, normally output, at the end of the structure provides unique conditions for the study of gradient limits. This allows high fields in the first cell for a comparatively low input power and a field distribution that rapidly falls off along the length of the structure. A maximum gradient of 130 MV/m in the first cell at a pulse length of 100 ns was reached for an input power of 31.9 MW. Details of the conditioning and operation at high-gradient are presented. Various breakdown rate measurements were conducted at different power levels and rf pulse widths. The structure was standard T24 CLIC test structure and was tested in Xbox-3 at CERN.

Poster TUPAB076 [1.077 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB076

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 12 August 2021

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TUPAB077

Novel Open Cavity for Rotating Mode SLED-Type RF Pulse Compressors

1547

X.W. Wu, A. Grudiev
CERN, Meyrin, Switzerland

A new X-band high-power rotating mode SLAC Energy Doubler (SLED)-type rf pulse compressor is proposed. It is based on a novel cavity type, a single open bowl-shape energy storage cavity with high Q₀ and compact size, which is coupled to the waveguide using a compact rotating mode launcher. The novel cavity type is applied to the rf pulse compression system of the main linac rf module of the klystron-based option of the Compact Linear Collider (CLIC). Quasi-spherical rotating modes of \rm{TE}_1,2,4 and \rm{TE}_1,2,13 are proposed for the correction cavity and storage cavity of the rf pulse compression system respectively. The storage cavity working at \rm{TE}_1,2,13 has a Q₀ of 240000 and a diameter less than 33 cm. The design of the pulse compressor and in particular of the high-Q cavity will be presented in detail.

Poster TUPAB077 [1.229 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB077

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB078

Relative Timing Jitter Effects on Two-stage Seeded FEL at SHINE

1551

H.X. Yang
SINAP, Shanghai, People’s Republic of China
H.X. Deng, B. Liu, D. Wang, K.S. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Funding: The National Key Research and Development Program of China (Grants No. 2016YFA0401901, No. 2018YFE0103100) and the National Natural Science Foundation of China (Grants No. 11935020, No. 11775293).
The synchronization between the ultrashort electron beam and external seed laser is essential for seeded FELs, especially for a multi-stage one. In this paper, we demonstrate a simple method to obtain the correlations between the pulse energy and relative timing jitter for evaluating the corresponding effects. In this method, the sensitivity of the output FEL performance against electron beam properties is demonstrated by scanning the electron beam and seed lasers, and the fitted curve is used to predict the pulse energy in different timing jitter by random sampling. The results indicate that the pulse energy of the first-stage EEHG is more stable than the second-stage HGHG. Meanwhile, the rise of bunch charge from 100 pC to 300 pC can reduce the timing control requirement by a factor of least 3 for the RMS timing jitter in our numerical simulations based on the parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. The timing jitter study can demonstrate the feasibility of the EEHG-HGHG cascading scheme in different current profiles for generating Fourier-transform-limited soft X-ray FEL.

Poster TUPAB078 [0.866 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB078

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paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021

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TUPAB079

Using ER@CEBAF to Show that a Multipass ERL Can Drive an XFEL

1555

G. Perez-Segurana
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
I.R. Bailey, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I.R. Bailey
Lancaster University, Lancaster, United Kingdom
R.M. Bodenstein, S.A. Bogacz, D. Douglas, Y. Roblin, T. Satogata
JLab, Newport News, Virginia, USA
T. Satogata
ODU, Norfolk, Virginia, USA
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility as an option for a potential UK-XFEL. Energy Recovery enables multi-MHz FEL sources, for example, an X-ray FEL oscillator or regenerative amplifier FEL. Additionally, combining with external lasers and/or self-interaction would provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power for nuclear and particle physics applications. An opportunity exists to demonstrate the necessary point-to-parallel longitudinal matches to drive an XFEL and successfully energy recover at the upcoming 5-pass up, 5-pass down Energy Recovery experiment on CEBAF at JLab termed ER@CEBAF. We show candidate matches and simulations supporting the minimal necessary modifications to CEBAF this will require. This includes linearisation of the longitudinal phase space in the injector and a reduction in the dispersion of the arcs, both of which increase the energy acceptance of CEBAF. We expect to commence initial tests of these adaptations on CEBAF during 2021.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB079

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paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021

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TUPAB080

Design and Status of the Beam Switchyard of the Shanghai Soft X-Ray FEL User Facility

1559

S. Chen, R. Wang
SSRF, Shanghai, People’s Republic of China
H.X. Deng, C. Feng, X. Fu, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

SXFEL-UF, a soft X-ray FEL user facility located in Shanghai, has been upgraded from the existing test facility. Electron energy increases from 840 MeV to 1.5 GeV and a SASE FEL line will be added besides the existing seeding FEL line. It has started commissioning since early this year. In order for simultaneous operation of the two FEL lines, a beam switchyard is built between the linac and the two FEL lines. In this paper, the physics design of the beam switchyard is described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB080

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paper received ※ 19 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021

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TUPAB081

Design of the Beam Distribution System of SHINE

1562

S. Chen, M. Gu, R. Wang
SSRF, Shanghai, People’s Republic of China
H.X. Deng, X. Fu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

In shanghai, a hard X-ray free electron laser project named SHINE is under design. It will be based on a superconducting linac running in CW mode. On the first stage, there will be three parallel undulator lines downstream the linac. For simultaneous operation of the three undulator lines, a beam distribution system based on fast kickers will be installed between linac and undulator lines. The physics design of this beam distribution system is described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB081

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 22 August 2021

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TUPAB082

Analysis of the Effect of Energy Chirp in Implementing EEHG at SXL

1566

M.A. Pop, F. Curbis, B.S. Kyle, S.P. Pirani, W. Qin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden
F. Curbis, S. Werin
Lund University, Lund, Sweden
W. Qin
DESY, Hamburg, Germany

As a part of the efforts to improve the longitudinal coherence in the design of the Soft X-ray FEL (the SXL) at MAX IV, we present a possible implementation of the EEHG harmonic seeding scheme partly integrated into the second bunch compressor of the existing LINAC. A special focus is given to the effect of CSR on the resulting EEHG bunching and on how this unwanted effect might be controlled.

Poster TUPAB082 [1.825 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB082

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paper received ※ 15 May 2021 paper accepted ※ 28 July 2021 issue date ※ 17 August 2021

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TUPAB083

Dual Energies in the LCLS Copper Linac

1570

F.-J. Decker, C. Bianchini Mattison, D.K. Bohler, A. Brachmann, W.S. Colocho, S. Condamoor, M.L. Gibbs, K.H. Kim, A.A. Lutman, T.J. Maxwell, J.A. Mock, H.-D. Nuhn, J.C. Sheppard, H. Smith, T.J. Smith, M. Stanek, S. Zelazny, Z. Zhang, C.M. Zimmer
SLAC, Menlo Park, California, USA

For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the superconducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.

Poster TUPAB083 [0.479 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB083

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021

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TUPAB084

An Empirically-Derived ABCD Matrix for Transverse Dynamics Studies in Seeded Free-Electron Lasers

1573

R. Robles
Stanford University, Stanford, California, USA
Z. Huang, G. Marcus
SLAC, Menlo Park, California, USA

Funding: DOE Contract DE-AC02-76SF00515.
We present a simple empirical method for deriving an ABCD matrix for studying the transverse dynamics of the radiation field in seeded, high-gain free-electron lasers before saturation. In spite of the inherently nonlinear nature of FEL optical guiding, the ABCD matrix we find is able to predict the evolution of the FEL mode size and centroid to a high degree of accuracy across a large range of input mode characteristics. This scheme enables extremely fast simulation of transverse dynamics, which in turn greatly simplifies numerical studies of seeded FEL systems. Of particular interest in that regard is the x-ray regenerative amplifier free-electron laser, in which the x-ray beam propagates through an optical cavity many hundreds of times, thereby making traditional simulation methods cumbersome and time consuming.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB084

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 11 August 2021

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TUPAB085

Three-Dimensional Radiative Effects in the Compression of Ultra-Short Electron Micro-Bunches

1577

R. Robles, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: DOE Contract DE-SC0009914 DOE Contract DE-SC0020409 National Science Foundation Grant No. PHY-1549132
Micro-bunched current profiles have recently gained traction as an alternative to bulk compression in certain free-electron laser applications. The attraction of the micro-bunched structure is owed in part to its promise to minimize deleterious effects associated with coherent synchrotron radiation during compression. Simultaneously, these profiles push the boundaries of traditional one-dimensional CSR simulation models which assume the bunch length to far exceed the transverse beam size in the bunch rest frame - an assumption which may be violated by the sub-micron length micro-bunches. Here we present simulation studies of the impact of three-dimensional CSR effects on micro-bunching based compression schemes using the General Particle Tracer code.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB085

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 13 August 2021

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TUPAB086

FLASH2020+ Plans for a New Coherent Source at DESY

1581

E. Allaria, N. Baboi, K. Baev, M. Beye, G. Brenner, F. Christie, C. Gerth, I. Hartl, K. Honkavaara, B. Manschwetus, J. Mueller-Dieckmann, R. Pan, E. Plönjes-Palm, O. Rasmussen, J. Rönsch-Schulenburg, L. Schaper, E. Schneidmiller, S. Schreiber, K.I. Tiedtke, M. Tischer, S. Toleikis, R. Treusch, M. Vogt, L. Winkelmann, M.V. Yurkov, J. Zemella
DESY, Hamburg, Germany

With FLASH2020+, a major upgrade of the FLASH facility has started to meet the new requirements of the growing soft-x ray user community. The design of the FEL beamlines aims at photon properties suitable to the needs of future user experiments with high repetition rate XUV and soft X-ray radiation. By the end of the project, both existing FEL lines at FLASH will be equipped with fully tunable undulators capable of delivering photon pulses with variable polarization. The use of the external seeding at 1 MHz in burst mode is part of the design of the new FLASH1 beamline, while FLASH2 will exploit novel lasing concepts based on different undulator configurations. The new FLASH2020+ will rely on an electron beam energy of 1.35 GeV that will extend the accessible wavelength range to the oxygen K-edge with variable polarization. The facility will be completed with new laser sources for pump and probe experiment and new experimental stations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB086

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 23 August 2021

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TUPAB087

Full Characterization of the Bunch-Compressor Dipoles for FLUTE

1585

Y. Nie, A. Bernhard, E. Bründermann, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, Y. Tong
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The Ferninfrarot Linac- Und Test-Experiment (FLUTE) is a KIT-operated linac-based test facility for accelerator research and development as well as a compact, ultra-broadband and short-pulse terahertz (THz) source. As a key component of FLUTE, the bunch compressor (chicane) consisting of four specially designed dipoles will be used to compress the 40-50 MeV electron bunches after the linac down to single fs bunch length. The maximum vertical magnetic field of the dipoles reach 0.22 T, with an effective length of 200 mm. The good field region is ±40 mm and ±10.5 mm in the horizontal and vertical direction, respectively. The latest measurement results of the dipoles in terms of field homogeneity, excitation and field reproducibility within the good field regions will be reported, which meet the predefined specifications. The measured 3D magnetic field distributions have been used to perform beam dynamics simulations of the bunch compressor. Effects of the real field properties on the beam dynamics, which are different from that of the ASTRA built-in dipole field, will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB087

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paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 01 September 2021

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TUPAB089

Proof-of-Principle Experiment Design for PEHG-FEL in SXFEL User Facility

1589

Z. Qi, H.X. Deng, C. Feng, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China
S. Chen, Z.T. Zhao
SSRF, Shanghai, People’s Republic of China

In this paper, we demonstrate a proof-of-principle experimental design for phase-merging enhanced harmonic generation (PEHG) free electron laser (FEL) in Shanghai Soft X-ray Free Electron Laser (SXFEL) user facility. The simulation results indicate that, taking advantage of the beam switchyard, the normal modulator and the seeded FEL line in SXFEL user facility, together with an oblique incident seed laser, we can perform the phase-merging effect in PEHG and finally get an 8.86nm FEL radiation through the undulator, which is the 30th harmonic of the seed laser.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB089

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 02 September 2021

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TUPAB092

Demonstration FELs Using UC-XFEL Technologies at the SAMURAI Laboratory

1592

N. Majernik, G. Andonian, O. Camacho, A. Fukasawa, G.E. Lawler, W.J. Lynn, B. Naranjo, J.B. Rosenzweig, Y. Sakai, O. Williams
UCLA, Los Angeles, California, USA
R. Robles
SLAC, Menlo Park, California, USA

Funding: DOE HEP Grant DE-SC0020409, National Science Foundation Grant No. PHY-1549132
The ultra-compact x-ray free-electron laser (UC-XFEL), described in [J. B. Rosenzweig, et al. 2020 New J. Phys. 22 093067], combines several cutting edge beam physics techniques and technologies to realize an x-ray free electron laser at a fraction of the cost and footprint of existing XFEL installations. These elements include cryogenic, normally conducting RF structures for both the gun and linac, IFEL bunch compression, and short-period undulators. In this work, several stepping-stone, demonstrator scenarios under discussion for the UCLA SAMURAI Laboratory are detailed and simulated, employing different subsets of these elements. The cost, footprint, and technology risk for these scenarios are considered in addition to the anticipated engineering and physics experience gained.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB092

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paper received ※ 19 May 2021 paper accepted ※ 11 August 2021 issue date ※ 02 September 2021

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TUPAB094

Multi-Start Foil Wound Solenoids for Multipole Suppression

1596

N. Majernik, A. Fukasawa, J.B. Rosenzweig, A. Suraj
UCLA, Los Angeles, California, USA

Funding: National Science Foundation Grant No. PHY-1549132 - CBB, DE-SC0020409
Solenoids for beam transport are typically wound helically, with each layer of wire being laid down on top of the previous, or as "pancakes" where the wire is wound radially in before crossing over and winding out. Both of these approaches break rotational symmetry and introduce higher-order multipole moments which can be deleterious to beam emittance. For high brightness beams, this can be particularly problematic. To this end, a solenoid employing multi-start foil windings is simulated and compared to conventional choices. With appropriate design, this approach can forbid certain multipoles by symmetry.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB094

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paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 15 August 2021

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TUPAB095

Arbitrary Longitudinal Pulse Shaping with a Multi-Leaf Collimator and Emittance Exchange

1600

N. Majernik, G. Andonian, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
D.S. Doran, G. Ha, J.G. Power, E.E. Wisniewski
ANL, Lemont, Illinois, USA
R.J. Roussel
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA

Funding: DOE HEP Grant DE-SC0017648, and National Science Foundation Grant No. PHY-1549132
Drive and witness beams with variable current profiles and bunch spacing can be generated using an emittance exchange beamline (EEX) in conjunction with transverse masks. Recently, this approach was used to create advanced driver profiles and demonstrate record-breaking plasma wakefield transformer ratios [Roussel, R., et al., Phys. Rev. Lett. 124, 044802 (2020)], a crucial advancement for effective witness acceleration. Presently, these transverse masks are individually laser cut, making the refinement of beam profiles a slow process. Instead, we have proposed the used of a UHV compatible multileaf collimator (MLC) to replace these masks. An MLC permits real-time adjustment of the beam masking, permitting faster optimization in a manner highly synergistic with machine learning. Beam dynamics simulations have shown that practical MLCs offer resolution that is functionally equivalent to that offered by the laser cut masks. In this work, the engineering considerations and practical implementation of such a system at the AWA facility are discussed and the results of benchtop tests are presented.
* Roussel, Ryan, et al. PRL 124.4 (2020): 044802

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB095

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paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 29 August 2021

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TUPAB098

Recent Progress Toward a Conduction-Cooled Superconducting Radiofrequency Electron Gun

1604

O. Mohsen, N. Adams, V. Korampally, A. McKeown, D. Mihalcea, P. Piot, I. Salehinia, N. Tom
Northern Illinois University, DeKalb, Illinois, USA
R. Dhuley, M.G. Geelhoed, D. Mihalcea, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA
P. Piot
ANL, Lemont, Illinois, USA

Funding: This work was supported by the US Department of Energy (DOE) under contract DE-SC0018367
High-repetition-rate electron sources have widespread applications. This contribution discusses the progress toward a proof-of-principle demonstration for a conduction-cooled electron source. The source consists of a simple modification of an elliptical cavity that enhances the field electric field at the photocathode surface. The source was cooled to cryogenic temperatures and preliminary measurements for the quality factor and accelerating field were performed. Additionally, we present future plans to improve the source along with simulated beam-dynamics performances.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB098

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paper received ※ 29 May 2021 paper accepted ※ 17 June 2021 issue date ※ 17 August 2021

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TUPAB099

Construction of an Infrared FEL at the Compact ERL

1608

R. Kato, M. Adachi, S. Eguchi, K. Harada, N. Higashi, Y. Honda, T. Miyajima, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, T. Shioya, M. Tadano, R. Takai, O.A. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima
QST, Tokai, Japan
N.P. Norvell
SLAC, Menlo Park, California, USA
F. Sakamoto
Akita National College of Technology, Akita, Japan
M. Shimada
HSRC, Higashi-Hiroshima, Japan

Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)".
The compact Energy Recovery Linac (cERL) has been in operation at KEK since 2013 to demonstrate ERL performance and develop ERL technology. Recently KEK has launched an infrared FEL project with a competitive funding. The purpose of this project is to build a mid-infrared FEL at the cERL, and to use that FEL as a light source for construction of the processing database required for industrial lasers. The FEL system is composed of two 3-m undulators and a matching section between them, and generates light with a maximum pulse energy of 0.1 micro-J at the wavelength of 20 microns with an 81.25 MHz repetition rate. The FEL is also expected to become a proof-of-concept machine for ERL base FELs for future EUV lithography.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB099

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paper received ※ 20 May 2021 paper accepted ※ 14 June 2021 issue date ※ 29 August 2021

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TUPAB100

FEL Design Elements of SABINA: A Free Electron Laser For THz-MIR Polarized Radiation Emission

1612

F. Dipace, E. Chiadroni, M. Ferrario, A. Ghigo, L. Giannessi, A. Giribono, L. Sabbatini, C. Vaccarezza
INFN/LNF, Frascati, Italy
A. Doria, A. Petralia
ENEA C.R. Frascati, Frascati (Roma), Italy
S. Lupi
Sapienza University of Rome, Roma, Italy
S. Macis
La Sapienza University of Rome, Rome, Italy
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy
V. Petrillo
INFN-Milano, Milano, Italy

Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program.
SABINA, acronym of "Source of Advanced Beam Imaging for Novel Applications", will be a Self-Amplified Spontaneous Emission Free Electron Laser (SASE FEL) providing a wide spectral range (from THz to MIR) of intense, short and variable polarization pulses for investigation in physics, chemistry, biology, cultural heritage, and material science. In order to reach these goals high brightness electron beams within a 30-100 MeV energy range, produced at SPARC photo-injector, will be transported up to an APPLE-X undulator through a dogleg. Space charge effects and Coherent Synchrotron Radiation (CSR) effects must be held under control to preserve beam quality. Studies on beam transport along the undulator and of the properties of the radiation field have been performed with "Genesis 1.3" simulation code. A downstream THz optics photon delivery system has also been designed to transport radiation on the long path from the undulator exit up to user experimental area.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB100

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paper received ※ 19 May 2021 paper accepted ※ 11 June 2021 issue date ※ 02 September 2021

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TUPAB101

Monte Carlo Simulations and Neutron and Gamma Fluence Measurements to Investigate Stray Radiation in the European XFEL Undulator System

1615

O.E. Falowska-Pietrzak, A. Hedqvist, F. Hellberg
Stockholm University, Stockholm, Sweden
N. Bassler
DCPT, Aarhus N, Denmark
A. Leuschner, D. Nölle
DESY, Hamburg, Germany
F. Wolff-Fabris
EuXFEL, Schenefeld, Germany

The European X-ray Free Electron Laser (XFEL) is an user facility research centre generating extremely bright and ultra-short SASE x-ray pulses. The laser flashes are generated when electrons of GeV energies pass the undulator systems. Even if the dominating contribution of the radiation field in the undulator is from spontaneous undulator radiation, also electron losses can be observed, e.g. during beam steering or due to beam halo, not captured by the upstream collimation system. The interactions of those particles with the vacuum vessel wall result in the emission of stray radiation. The LB 6419 detector allows to measure both the neutron and the gamma component in the pulsed radiation fields nearby the undulators*. Usually, the real-time measurements show the dominance of the gamma signals. However, in case of particle loss occurs, a neutron signal is observed. In addition, Monte Carlo (MC) simulations conducted using the Geant4 code indicate that neutrons are also present within the undulator’s magnets volume. In this work, we present the LB 6419 measurement data and compare these to our MC simulations, to characterize the radiation field nearby the undulator segment.
* KLETT, A., LEUSCHNER, A., TESCH, N., A dose meter for pulsed neutron fields, Radiat Meas 45 (2010) 1242-1244

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB101

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 18 August 2021

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TUPAB102

A New 2nd Bunch Compression Chicane for the FLASH2020+ Project

1618

M. Vogt, J. Zemella
DESY, Hamburg, Germany

The first stage of the FLASH2020+ project is an upgrade of the FLASH injector beamline. Within this framework, the 2nd bunch compression chicane (BCC) will be completely redesigned. The old S-chicane will be replaced with a new C-chicane which is 3.5m shorter thereby generating space a new section for re-matching the beam from the injector into the linac. The new BCC will be equipped with quad/skew-quad units in both legs of the chicane to compensate correlations of the transverse degrees of freedom with the longitudinal ones. Since quadrupoles tend to have a circular bore, the chicane is designed with movable round vacuum chambers and movable dipoles for maintaining full flexibility in choosing the compression parameters. This article describes the technical details and introduces a thin-lens model of BCCs which allows analytical estimates on the effects of powering the quad/skew-quad units on optics parameters as well as estimates on the required strengths of these magnets in order to remove correlations of the magnitudes typically observed at FLASH.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB102

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 29 August 2021

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TUPAB103

Discussion on CSR instability in EEHG Simulation

1622

D. Samoilenko, W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
F. Curbis, M.A. Pop, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden
P. Niknejadi, G. Paraskaki
DESY, Hamburg, Germany
F. Pannek
University of Hamburg, Hamburg, Germany

Echo-Enabled Harmonic Generation (EEHG) is an external seeding technique for XUV and soft X-ray Free Electron Lasers (FEL). It has recently been experimentally demonstrated and currently many facilities worldwide intend to incorporate it in user operation. The EEHG process relies on very accurate and complex transformations of electron beam phase space by means of a series of undulators coupled to lasers and dispersive chicanes. As a result of the phase space manipulation, electrons are bunched at a high harmonic of the seed laser wavelength allowing coherent emission at few nm wavelength. Dispersion occurring in strong chicanes is imperative for implementation of this scheme and effective electron bunching generation. However, strong chicanes at the same time can be source of beam instability effects, such as Coherent Synchrotron Radiation (CSR), that can significantly grow in these conditions and suppress the bunching process. Therefore, there is a common need to investigate such effects in detail. Here, we discuss their treatment with simulation codes applied to a typical EEHG setup.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB103

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 12 August 2021

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TUPAB104

Redesign of the FLASH2 Post-SASE Undulator Beamline

1626

F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is one of the two SASE (Self-Amplified Spontaneous Emission) undulator beamlines lines comprising variable gap undulators to produce radiation in the XUV and soft X-ray regime at FLASH. Downstream of the SASE undulators the beamline is currently undergoing a major redesign. During shutdowns in summer 2020 and winter 2021 two PolariX TDSs (Polarizable X-band Transverse Deflecting Structure) were installed, as well as additional diagnostics, to monitor the longitudinal phase space density of the electron bunches. Additionally, an afterburner undulator will be integrated in the next shutdown to produce circularly polarized light with wavelengths down to 1.39 nm. In this paper, we will present the modifications that were and will be made to the electron beamline in the course of this redesign.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB104

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 23 August 2021

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TUPAB105

Simulation Studies for Dark Current Signature From DLS RF Gun

1630

J. Karmakar, M. Aggarwal, S. Ghosh, B. Karmakar, P. Patra, B.K. Sahu, A. Sharma
IUAC, New Delhi, India

The Delhi Light source (DLS) is an upcoming compact THz facility at IUAC, New Delhi, based on pre-bunched FEL. RF conditioning of the 2.6 cell S-band RF gun is presently carried out with a Cu photo-cathode (PC) plug and dark current is produced when substantial accelerating field is reached inside the cavity. To identify the possible field emission sites contributing to dark current, single electron ASTRA simulations are done with a phase scan of the RF field. The simulation is extended to include multi-particle emission from the PC edge as a ring. The energies present in the dark current is analysed from the the Fowler Nordheim current plot and energy phase scan plot. The distribution of few dark current energies and their respective trajectories upto the YAG screen at a given solenoid setting is traced and shown in the simulations. We also present the dark current images captured during the initial RF conditioning and try to compare it with the simulations.

Poster TUPAB105 [0.742 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB105

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paper received ※ 19 May 2021 paper accepted ※ 17 August 2021 issue date ※ 01 September 2021

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TUPAB106

Simulation Calculations of Compact THz Facility at IUAC, New Delhi

1633

J. Karmakar, S. Ghosh
IUAC, New Delhi, India

A compact THz radiation source based on the principle of pre-bunched Free Electron Laser is at the commissioning stage at Inter University Accelerator Centre (IUAC), New Delhi. The facility will generate low emittance train of electron micro-bunches (2, 4, 8 or 16 numbers) from a RF photo-cathode gun in the energy range of 4 to 8 MeV and inject into a compact undulator to generate coherent THz radiation in the frequency range of ~0.18 to 3.0 THz. To optimize the intensity at a given frequency, the beam bunching factor and the betatron oscillation amplitude in the non-wiggling plane of the electronμbunches inside the undulator has been maximized and minimized respectively. The paper presents the optimized beam optics simulation results for two frequencies viz 0.5 and 2 THz. The on-axis radiation spectral intensity computed by in-house developed code using the trajectory data of the beam optics simulation is also presented for the two frequencies.

Poster TUPAB106 [1.208 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB106

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paper received ※ 18 May 2021 paper accepted ※ 31 August 2021 issue date ※ 12 August 2021

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TUPAB107

Accelerator and Light Source Research Program at Duke University

1636

Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
The accelerator and light source research program at Duke Free-Electron Laser Laboratory (DFELL), TUNL, is focused on the development of the storage ring based free-electron lasers (FELs) and a state-of-the-art Compton gamma-ray source, the High Intensity Gamma-ray Source (HIGS) driven by the storage ring FEL. With a maximum total flux of about 3·10¹⁰ gamma/s and a spectral flux of more than 1,000 gamma/s/eV around 10 MeV, the HIGS is the world’s highest-flux Compton gamma-ray source. Operated in the energy range from 1 to 100 MeV, the HIGS is a premier Compton gamma-ray facility in the world for a variety of nuclear physics research programs, both fundamental and applied. In this work, we will describe our recent light source development to enable the production of gamma rays in the higher energy range from 100 and 120 MeV. We will also provide a summary of our recent accelerator physics and FEL physics research activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB107

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paper received ※ 26 May 2021 paper accepted ※ 14 July 2021 issue date ※ 15 August 2021

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TUPAB109

Characterization of the X-Ray Angular Pointing Jitter in the LCLS Hard X-ray Undulator Line

1640

R.A. Margraf, Z. Huang, J.P. MacArthur, G. Marcus, T. Sato, D. Zhu
SLAC, Menlo Park, California, USA
Z. Huang
Stanford University, Stanford, California, USA

Funding: This work was supported by the Department of Energy, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515.
The angular pointing jitter of X-ray pulses produced by an X-ray Free-Electron Laser (XFEL) depends on both intrinsic properties of the SASE (Self-amplified spontaneous emission) process and jitters in beamline variables such as electron orbit. This jitter is of interest to the Cavity-Based XFEL (CBXFEL)* project at SLAC, which will lase seven undulators inside an X-ray cavity of four diamond Bragg mirrors. The CBXFEL cavity has a narrow angular bandwidth, thus large angular jitters cause X-rays to leak out of the cavity and degrade cavity efficiency. To understand contributors to angular pointing jitter, we studied the pointing jitter of the Linac Coherent Light Source (LCLS) Hard X-ray Undulator line (HXU). Monochromatic and pink X-rays were characterized at the X-ray Pump Probe (XPP) instrument. We found pulses with high monochromatized pulse energy and small electron beam orbit in the undulator have the lowest angular pointing jitter. We present here our measurement results, discuss why these factors correlate with pointing stability, and propose a strategy for CBXFEL to reduce angular pointing jitter and account for angular pointing jitter in cavity efficiency measurements.
*Gabriel Marcus et al. "CBXFEL Physics Requirements Document for the Optical cavity Based X-Ray Free Electron Lasers Research and Development Project." SLAC-I-120-103-121-00. Apr 2020.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB109

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 14 August 2021

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TUPAB110

Measurement and Correction of RF Kicks in the LCLS Accelerator to Improve Two-Bunch Operation

1644

R.A. Margraf, F.-J. Decker, Z. Huang, G. Marcus
SLAC, Menlo Park, California, USA
Z. Huang
Stanford University, Stanford, California, USA

Funding: This work was supported by the Department of Energy, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515.
RF kicks, caused by a misalignment of an electron beam and acceleration structure, produce an electron orbit in the accelerator which decreases the final energy of the accelerated electron beam and is detrimental to lasing electron bunches in an X-ray Free Electron Laser (XFEL). RF kicks can depend on the RF waveform of the accelerating structure, so controlling this effect is particularly important when two or more electron bunches are accelerated within an RF fill time. Multibunch modes have been successfully developed for the Linac Coherent Light Source (LCLS) accelerator at SLAC,* and are being continually improved to accommodate new experiments. One such experiment, the Cavity-Based XFEL (CBXFEL)** project will require two electron bunches separated by 218.5 ns which must be identical in energy and orbit. To reduce variation in energy and orbit between the two bunches, we studied the RF kicks produced by each of 75 accelerator segments in the LCLS linac at several RF timings. Here, we discuss these measurements and propose a method to correct RF kicks in the LCLS accelerator using corrector dipoles and quadrupoles.
* F.-J. Decker, et al. Recent Developments and Plans for Two Bunch Operation, Proc. of FEL2017, TUP023.
** Gabriel Marcus et al. CBXFEL Physics Requirements Document. SLAC-I-120-103-121-00. 2020.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB110

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 29 August 2021

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TUPAB111

Layout of the Laser Heater for FLASH2020+

1647

C. Gerth, E. Allaria, A. Choudhuri, L. Schaper, E. Schneidmiller, S. Schreiber, M. Tischer, P. Vagin, M. Vogt, L. Winkelmann, M.V. Yurkov, J. Zemella
DESY, Hamburg, Germany

The major upgrade FLASH2020+ of the FEL user facility FLASH includes an improved injector layout for the generation of the high-brightness electron beam as well as an externally seeded FEL beamline. Microbunching gain of initial modulations or shot-noise fluctuations degrade the electron beam quality, which is in particular harmful to the external seed process. To minimize the microbunching gain by a controlled increase of the uncorrelated energy spread, the installation of a laser heater is foreseen directly upstream of the first bunch compression chicane. In this paper, we present the layout of the laser heater section, which follows the original proposal published almost 20 years ago and differs in several aspects from the common layout implemented at many other FEL facilities. The considerations that have been made for the optimisation of the laser heater parameters are described in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB111

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 01 September 2021

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TUPAB113

Highlights From the Conceptual Design Report of the Soft X-Ray Laser at MAX IV

1651

F. Curbis, J. Andersson, L. Isaksson, B.S. Kyle, F. Lindau, E. Mansten, H. Tarawneh, P.F. Tavares, S. Thorin, A.S. Vorozhtsov
MAX IV Laboratory, Lund University, Lund, Sweden
S. Bonetti
Stockholm University, Stockholm, Sweden
V.A. Goryashko, P.M. Salén
Uppsala University, Uppsala, Sweden
P. Johnsson, S.P. Pirani, M.A. Pop, W. Qin, S. Werin
Lund University, Lund, Sweden
M. Larsson
Stockholm University, Department of Physics, Stockholm, Sweden
A. Nilsson
FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
J.A. Sellberg
KTH Physics, Stockholm, Sweden

Funding: Knut and Alice Wallenberg Foundation
The SXL (Soft X-ray Laser) project developed a conceptual design for a soft X-ray Free Electron Laser in the 1–5 nm wavelength range, driven by the existing MAX IV 3 GeV linac. In this contribution we will focus on the FEL operation modes developed for the first phase of the project based on two different linac modes. The design work was supported by the Knut and Alice Wallenberg foundation and by several Swedish universities and organizations (Stockholm, Uppsala, KTH Royal Institute of Technology, Stockholm-Uppsala FEL center, MAX IV laboratory and Lund University).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB113

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 19 August 2021

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TUPAB114

FEL Performance and Beam Quality Assessment of Undulator Line for the CompactLight Facility.

1655

H.M. Castañeda Cortés, D.J. Dunning, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: H2020 CompactLight has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 777431
The H₂020 CompactLight Project aims for the design of innovative, cost-effective, compact FEL facilities to generate higher peak brilliance radiation in the soft and hard X-ray. In this paper we assess via simulation studies the performance of a variably polarising APPLE-X afterburner positioned downstream of a helical Super Conducting Undulator (SCU). We discuss the optimum balance between the active SCU length and the afterburner length, considering the peak brilliance and pulse energy of the output. Our studies are complemented with analysis of the optical beam quality of the afterburner output to determine the design constraints of the photon beamline that delivers the FEL output to the experimental areas.
* Mak, A., Salen, P., Goryashko, V., Clarke, J., http://uu.diva-portal.org/smash/record.jsf?pid=diva2\%3A1280300&dswid=3236
** Lutman, A. et al. Nature Photonics 10, 468

Poster TUPAB114 [1.210 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB114

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paper received ※ 11 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB115

Status Report of the Superconducting Free-Electron Laser FLASH at DESY

1659

J. Rönsch-Schulenburg, F. Christie, K. Honkavaara, M. Kuhlmann, S. Schreiber, R. Treusch, M. Vogt, J. Zemella
DESY, Hamburg, Germany

The free-electron laser in Hamburg (FLASH) is a high brilliance XUV and soft X-ray SASE FEL user-facility at DESY. FLASH’s superconducting linac can accelerate several thousand electron bunches per second in 10 Hz bursts of up to 800 µs length. The long bunch trains can be split in two parts and shared between two undulator beamlines. During 2020, FLASH supplied, in standard operation, up to 500 bunches at 10 Hz in two bunch trains with independent fill patterns and compression schemes. The FLASH2 undulator beamline comprises variable gap undulators that allow different novel lasing schemes. A third beamline accommodates the FLASHForward plasma wakefield acceleration experiment. We report on the FLASH operation in 2019 - 2021 and present a few highlights.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB115

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 19 August 2021

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TUPAB116

Toward THz Coherent Undulator Radiation Experiment with a Combination of Velocity Bunchings

1663

Y. Sumitomo, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, T. Tanaka
LEBRA, Funabashi, Japan

Funding: Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research (KAKENHI), Grant Number JP19K12631.
We have launched a research program to generate the THz coherent undulator radiations, following the proposal of the combination of velocity bunchings * at Nihon University. The combination of velocity bunchings is an efficient way of bunch compression allowing a range of energy choices, in other words, a range of quasi-monochromatic radiation wavelengths generated at the undulator. In addition to the existing wideband THz light sources (0.1 - 2 THz) by the coherent edge and transition radiations currently available at Nihon Univ., the development of a high peak-power and quasi-monochromatic coherent radiation should accelerate the activities including the material science related to the THz bandwidths. In this presentation, we illustrate the program and report the current status of the experiment.
* Y. Sumitomo et al., J. Phys. Conf. Ser., vol. 1067, p. 032017, 2018.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB116

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 15 August 2021

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TUPAB117

Eigenmode Decomposition for Free-Electron Lasers Using Bayesian Analysis

1666

P. Liu, W. Li, Y.K. Wu, J. Yan
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
Laser beams from an optical cavity, such as free-electron laser (FEL) resonators, are typically a mixture of the cavity’s eigenmodes, such as the Hermite-Gaussian (HG) modes or Laguerre-Gaussian (LG) modes. Robust evaluation of the eigenmode spectrum of a multimode laser beam has various applications in laser development, research, and utilization. In this work, a general eigenmode decomposition method for a multimode laser beam has been developed based on Bayesian analysis. This problem is transformed into a linear system and then solved using a Gaussian probabilistic model. Using Bayesian analysis, prior knowledge about the mode content is further incorporated into the solution to improve the results for laser beams contaminated with complex disturbances. The decomposition of the beam image from the incoherent intensity addition of HG modes is discussed with different types of noise or disturbances. The simulation results have been used to show the robustness of this method. This method can be straightforwardly extended into other cases such as the wavefront decomposition into the coherent superposition of HG and LG modes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB117

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 01 September 2021

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TUPAB119

Beam Loss Study for the Implementation of Dechirper at the European XFEL

1670

J.J. Guo
University of Chinese Academy of Sciences, Beijing, People’s Republic of China
W. Decking, M.W. Guetg, J.J. Guo, S. Liu, W. Qin, I. Zagorodnov
DESY, Hamburg, Germany
Q. Gu, J.J. Guo
SINAP, Shanghai, People’s Republic of China
Q. Gu
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

The European XFEL is a free-electron laser facility based on superconducting linac with high repetition rate up to 4.5 MHz. Wakefield structure (also called dechirper module) is planned to be installed in front of the SASE beam line at the European FEL, which can be used as a kicker for two-color scheme or a dechirper to control the bandwidth of SASE radiation. When the beam pass through the dechirper module, strong longitudinal and transverse wakefields can be excited to introduce a correlated energy chirp and a kick along the bunch. However, due to the relatively small gap of dechirper, beam halo particles hitting the dechirper module can lead to energy deposition and generate additional radiation, which can cause serious damage to the downstream undulators. For this reason, simulations have been performed using BDSIM to define the maximum acceptable beam halo, and the results are presented in this paper.

Poster TUPAB119 [1.489 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB119

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paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 12 August 2021

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TUPAB121

Photoinjector Drive Laser Temporal Shaping for Shanghai Soft X-Ray Free Electron Laser

1674

C.L. Li, X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
X.L. Dai
SSRF, Shanghai, People’s Republic of China
H.X. Deng, L. Feng, B. Liu, J.G. Wang
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Shanghai soft X ray free electron laser (SXFEL) initial designed shape of the photocathode driver laser is flattop produced by α-BBO stacking. The advantage of this design is attractive in producing electron bunch with low initial emittance and high uniformity along the electron bunch. However, some unavoidable modulations are generated along the laser pulse which trigger the electron bunch modulation generated at the source, which is due to the fast response time (tens of femtosecond) of copper cathode. In order to eliminate the modulation of electron bunch, temporal Gaussian driver laser was designed and tested, measurement results show the electron bunch longitudinal modulation was removed. In this paper, we present two kinds of driver laser pulse temporal shaping methods based on α-BBO stacking and UV grating pair shaping. Moreover, corresponding electron bunch temporal profile are also presented.

Poster TUPAB121 [2.469 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB121

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 25 August 2021

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TUPAB122

SASE3 Variable Polarization Project at the European XFEL

1678

S.K. Karabekyan, S. Abeghyan, M. Bagha-Shanjani, S. Casalbuoni, U. Englisch, G. Geloni, J. Grünert, S. Hauf, C. Holz, D. La Civita, J. Laksman, D. Mamchyk, M.P. Planas, F. Preisskorn, S. Serkez, H. Sinn, A. Violante, G. Wellenreuther, M. Wuenschel, M. Yakopov, C. Youngman
EuXFEL, Schenefeld, Germany
A. Block, W. Decking, N. Golubeva, K. Knebel, T. Ladwig, D.L. Lenz, D. Lipka, R. Mattusch, N. Mildner, E. Negodin, D. Nölle, J. Prenting, F. Saretzki, M. Schlösser, F. Schmidt-Föhre, E. Schneidmiller, D. Thoden, T. Wamsat, S. Wendt, T. Wilksen, T. Wohlenberg, M.V. Yurkov
DESY, Hamburg, Germany
M. Brügger, M. Calvi, S. Danner, R. Ganter, L. Huber, A. Keller, M.S. Schmidt, T. Schmidt
PSI, Villigen PSI, Switzerland
D.E. Kim
PAL, Pohang, Republic of Korea
Y. Li
IHEP, People’s Republic of China

At the European XFEL, two undulator systems for hard and one for soft X-rays have been successfully put into operation. The SASE3 soft X-ray undulator system generates linearly polarized radiation in the horizontal plane. One of the requirements for extending the radiation characteristics is the ability to obtain different polarization modes. These include both right and left circular, elliptical polarization, or linear polarization at an arbitrary angle. For this purpose, a system consisting of four APPLE X helical undulators developed at the Paul Scherrer Institute (PSI) is used. This paper presents the design parameters of the SASE3 undulator system after modifying it with the helical afterburner. It also describes the methods and the design solutions different from those used at PSI. The status and schedule of the project are introduced.

Poster TUPAB122 [0.553 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB122

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 27 August 2021

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TUPAB125

Studies of Particle Losses From the Beam in the EU-XFEL Following Scattering by a Slotted Foil

1681

A.T. Potter, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
W. Decking, S. Liu
DESY, Hamburg, Germany
F. Jackson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

One technique for producing short radiation pulses in an FEL involves the use of a slotted foil in a bunch compressor. However, the scattering of particles from the foil can lead to increased particle losses and the generation of secondary particles. This is a particular concern for high rep-rate FELs, such as the European XFEL, where there are plans to implement the slotted-foil technique for short pulse generation. The study reported here aims to characterise the impact of a slotted foil in the European XFEL on the radiation dose in the front section of one of the undulators. Simulations were performed using BDSIM: this code tracks primary particles along the beamline, models the interaction between particles and accelerator components and tracks secondary particles produced by these interactions. The results indicate the amount of energy deposited in the front section of one of the FEL undulators, and provide a basis for optimisation of the collimation system to keep the energy deposition and radiation doses within acceptable limits.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB125

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 28 August 2021

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TUPAB126

Spectral Gap in the Middle Infrared FEL Oscillator of FELiCHEM

1685

Y.P. Zhu, H.T. Li, Z. Zhao
USTC/NSRL, Hefei, Anhui, People’s Republic of China

A phenomenon of spectral gap is observed in the Middle Infrared FEL Oscillator of FELiCHEM: the laser power falls down at the particular wavelength. Starting with the experimental data, this paper focuses on the simulation calculation and analysis of the effect from using the partial waveguide. The relationship between waveguide and spectral gap is revealed.

Poster TUPAB126 [1.063 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB126

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paper received ※ 17 May 2021 paper accepted ※ 14 June 2021 issue date ※ 21 August 2021

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TUPAB127

Spare Gun Multi-Physics Analysis for LCLS-II

1688

L. Xiao, C. Adolphsen, A. Cedillo, E.N. Jongewaard, X. Liu, C.-K. Ng, F. Zhou
SLAC, Menlo Park, California, USA

LBNL APEX VHF normal conducting gun was adopted for LCLS-II CW operation to provide ultra-bright high repetition rate X-ray pulses. The initial LCLS-II gun and injector commissioning showed excessive dark current dominated by field emission around the cathode plug outer diameter and the gun cavity nose. There is a concern that the dark current may get worse with time of operation. It is planning to build a spare rf gun largely based on the current LCLS-II gun to replace current LCLS-II gun. The proposed spare gun has a reduced the peak electrical fields around the cathode plug corner and cavity nose by 10% through further optimizing APEX gun cavity shape. In addition, there are some moderate modifications on the engineering design to increase mechanical robustness and vacuum performance. SLAC developed parallel finite-element electromagnetic code suite ACE3P is used to apply for the spare gun modeling including RF, thermal and structural analysis at static and transient states to ensure its successful operation in LCLS-II. In this paper, the spare gun multi-physics analysis is described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB127

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paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 12 August 2021

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TUPAB129

Beam Based Alignment in a Compact THz-FEL Facility

1692

Q.S. Chen, T. Hu, K.F. Liu, B. Qin, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China

In this paper, we presented the beam based alignment results in a compact THz-FEL facility. The alignment was divided into two sections, the transport line and the optical line. In the transport line, all the five quadrupoles upstream of the undulator were adjusted one by one to fit the electron beam from the traveling wave linac. In the optical line, a set of auxiliary coils were winded on the yokes of the quadrupole downstream of the double bend achromat (DBA) to produce a vertical steering force. Another combined steering magnet, together with the auxiliary coils, corrected the beam orbit in the optical line. With the dispersion free test, the displacement between the magnetic centers of the quads and the beam orbit was less than 0.1mm.

Poster TUPAB129 [0.673 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB129

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021

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TUPAB131

Measurement of Coherent Smith-Purcell Radiation Using Ultra-Short Electron Bunch at T-Acts

1696

H. Yamada, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, K. Shibata, K. Takahashi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

The coherent Smith-Purcell radiation (SPR) emitted as a short electron bunch passes over a periodic metal surface is expected to be applied as a non-destructive beam diagnostic tool. The longitudinal profile of the electron bunch can be deduced by the measured spectrum of the coherent SPR, which is compared with the theoretical one for single electron. There are several theoretical models that explain the SPR mechanism, such as the surface current (SC) model and the van den Berg model. But the difference of estimation in radiation intensity between different models is not trivial, and also the experimental data to evaluate those validity is not enough. At test accelerator, t-ACTS, in Tohoku University we are conducting experimental research on coherent SPR in the terahertz frequency region using an ultra-short electron bunch of about 100 fs. The status and results of the experiment will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB131

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 13 August 2021

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TUPAB133

Brazing free RF Pulse Compressor for High Gradient Accelerators

1700

L. Kankadze, D. Alesini, F. Cardelli, G. Di Raddo, M. Diomede
INFN/LNF, Frascati, Italy

EURPRAXIA@SPARC\_LAB, is a proposal to upgrade the SPARC\_LAB test facility (at LNF, Frascati) to a soft X-ray user facility based on plasma acceleration and high-gradient X-band (11.9942 GHz) accelerating modules. Each module is made up of a group of 4 TW sections assembled on a single girder and fed by one klystron by means of one rf pulse compressor system and a low attenuation circular waveguide network that transports the rf power to the input hybrids of the sections. The pulse compressor is based on a single Barrel Open Cavity (BOC). The BOC use a ’whispering gallery’ mode which has an intrinsically high quality factor and operates in a resonant rotating wave regime. Compared to the conventional SLED scheme it requires a single cavity instead of two cavities and a 3-dB hybrid. A new brazeless mechanical design has been proposed and is described in the present paper together with the electro-magnetic and thermo-mechanical simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB133

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paper received ※ 21 May 2021 paper accepted ※ 15 June 2021 issue date ※ 10 August 2021

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TUPAB134

Linac-to-Booster Optimization Procedure Towards High Transmission for the Alba Injector

1703

R. Muñoz Horta, D. Lanaia, E. Marín, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a third generation synchrotron light source that consists of 3 accelerators (Linac, Booster and Storage ring) and two transfer lines, Linac-to-Booster (LTB) and Booster-to-Storage (BTS). The ALBA accelerators team has defined a robust procedure that optimizes the beam performance from Linac to Booster in terms of transmission and stability. The implemented beam-based alignment and global orbit correction techniques have been investigated first in simulations and afterwards successfully implemented in the machine.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB134

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paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021

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TUPAB136

On Nonlinear Electron Beam Dynamics in a Plasma Environment

1707

H.Y. Barminova
MEPhI, Moscow, Russia
B. Kakpresenter
RUDN University, Moscow, Russia

The nonlinear dynamics of an electron beam propagating in a low-density plasma is investigated. The beam envelope equation is obtained analytically for the case of an axisymmetric beam using a model approximation close to the Kapchinsky-Vladimirsky model. Solutions of the envelope equation are presented for various initial conditions (beam current, initial beam radius, transverse beam emittance).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB136

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paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 26 August 2021

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TUPAB138

Determination of the Phase of Wakefield Driven by a Self-Modulated Proton Bunch in Plasma

1710

K. Moon, M. Chung
UNIST, Ulsan, Republic of Korea
P. Muggli
MPI-P, München, Germany

Funding: This work was partly supported by the National Research Foundation of Korea (Nos. NRF-2016R1A5A1013277 and NRF-2020R1A2C1010835)
The phase of wakefield driven by a self-modulated proton bunch depends on the type of seeding method and by the beam-plasma parameters.* Particularly when a preceding electron bunch generates seed wakefield, the proton bunch modulation is strongly affected by the seed bunch dynamics along with the plasma. Intrinsic wakefield dephasing from self-modulation of proton bunch can lead to complex evolution of the bunch and wakefield, making it difficult to design an experimental setup for witness beam injection. Using the particle-in-cell code FBPIC,** we investigate in detail the trends of seed electron and driver proton bunch parameter sensitivity to the phase of wakefield in time in the proton bunch frame. We focus on the parameters affecting the phase of the wakefield through the beam’s radial dynamics, such as beam emittance, radial size, energy, and beam to plasma density ratio. Parameter variations are compared to those in the case of the phase of wakefield driven by a non-evolving seed bunch.
*F. Batsch, arXiv:2012.09676 [physics.plasm-ph]
**R. Lehe, M. Kirchen, I.A. Andriyash, B.B. Godfrey, and J.-L. Vay, Comput. Phys. Comm. 203, 66-82 (2016)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB138

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB141

On the Development of a Low Peak-Power, High Repetition-Rate Laser Plasma Accelerator at IPEN

1713

A. Bonatto
Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
E.P. Maldonado
ITA, São José dos Campos, Brazil
R.P. Nunes
UFRGS, Porto Alegre, Brazil
R.E. Samad, F.B.D. Tabacow, N.D. Vieira, A.V.F. Zuffi
IPEN-CNEN/SP, São Paulo, Brazil

Funding: FAPESP (Grant #2018/25961), CNPq and CAPES.
In this work, the current status on the development of a laser plasma accelerator at the Nuclear and Energy Research Institute (Instituto de Pesquisas Nucleares e Energéticas, IPEN/CNEN), in São Paulo, Brazil, is presented. Short pulses to be produced by an under-development near-TW, kHz laser system will be used to ionize a gas jet, with a density profile designed to optimize the self-injection of plasma electrons. The same laser pulse will also drive a plasma wakefield, which will allow for electron acceleration in the self-modulated regime. The current milestone is to develop the experimental setup, including electron beam and plasma diagnostics, required to produce electron bunches with energies of a few MeV. Once this has been achieved, the next milestone is to produce beams with energies higher than 50 MeV. Besides kickstarting the laser wakefield accelerator (LWFA) technology in Brazil, this project aims to pave the way for conducting research on the production of radioisotopes by photonuclear reactions, triggered by LWFA-accelerated beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB141

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 10 August 2021

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TUPAB142

Simulation Study of Laser Wakefield Acceleration Varying the Down-Ramp Length of a Gas Jet

1717

R.P. Nunes
UFRGS, Porto Alegre, Brazil
A. Bonattopresenter
Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
E.P. Maldonado
ITA, São José dos Campos, Brazil
R.E. Samad, N.D. Vieira
IPEN-CNEN/SP, São Paulo, Brazil

In this work, particle-in-cell simulations were carried out to investigate the role of the down-ramp length of a H\textsubscript{2} gas jet in accelerating electrons ionized by the laser pulse. The laser and plasma density were chosen so that the system is operating in the self-modulated regime. Preliminary results show how the down-ramp length can control the injection of electrons in the first bubble induced in the plasma by the laser pulse.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB142

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paper received ※ 20 May 2021 paper accepted ※ 15 June 2021 issue date ※ 13 August 2021

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TUPAB143

Laser Pulse Dynamics in the Self-Modulated Regime

1721

R.P. Nunes
UFRGS, Porto Alegre, Brazil
A. Bonattopresenter
Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
E.P. Maldonado
ITA, São José dos Campos, Brazil
R.E. Samad, N.D. Vieira
IPEN-CNEN/SP, São Paulo, Brazil

In this work, particle-in-cell simulations were carried out to investigate the dynamics of a laser pulse propagating along a H₂ gas jet. The laser-driven wakefield and the density of ionized electrons are analyzed during the pulse propagation through the gas jet. The laser and plasma quantities were chosen in order to have the system operating in the self-modulated regime. Results show how the self-modulation fragments the laser pulse, originating higher-amplitude pulses that can induce bubble formation with wave-breaking and particle injection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB143

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 21 August 2021

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TUPAB145

Methods for Numerical Noise Mitigation in Quasistatic Three-Dimensional Particle-in-Cell Code LCODE3D

1725

I.Yu. Kargapolov, K.V. Lotov, A. Sosedkin
Budker INP & NSU, Novosibirsk, Russia
I.A. Shalimova
ICM&MG SB RAS, Novosibirsk, Russia
I.A. Shalimova, P.V. Tuev
NSU, Novosibirsk, Russia
P.V. Tuev
BINP SB RAS, Novosibirsk, Russia

We discuss a new quasistatic 3D particle-in-cell code LCODE3D for simulating plasma wakefield acceleration, which is a modified version of the quasistatic 2D3V code LCODE, focus on the numerical noise of the plasma solver and propose methods for reducing it. We compare different particle shape functions, as these functions affect the code stability. We also introduce the so-called dual plasma approach, which improves stability and dampens small-scale noise. After applying the proposed methods, the results of the new code closely agree with LCODE simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB145

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 25 August 2021

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TUPAB146

High Brightness Electron Beams from Dragon Tail Injection and the E-312 Experiment at FACET-II

1728

P. Manwani, N. Majernik, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colorado, USA
B. Hidding
USTRAT/SUPA, Glasgow, United Kingdom
M.D. Litos
Colorado University at Boulder, Boulder, Colorado, USA

Funding: This work was performed with support of the US Department of Energy under Contract No. DE-SC0009914
The advent of optically triggered injection in multi component plasma wakefield accelerators has been shown to enable a substantial increase in witness electron beam quality. Here we present a novel way of using the overlap of laser and beam radial fields to locally liberate electrons from the tunneling ionization of the non-ionized gas species. These liberated ultracold electrons gain sufficient energy to be trapped in the accelerating phase at the back of the plasma blowout. This method of controlled injection has advantages in precision timing since injection is locked to peak beam current and has the potential of generating beams with very low emittance and energy spread. This method has been investigated using particle-in-cell (PIC) simulations. This scenario corresponds to a planned experiment, E-312, at SLAC’s FACET-II facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB146

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paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 22 August 2021

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TUPAB147

Asymmetric Beam Driven Plasma Wakefields at the AWA

1732

P. Manwani, H.S. Ancelin, G. Andonian, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, California, USA
G. Andonian
RadiaBeam, Santa Monica, California, USA
G. Ha, J.G. Power
ANL, Lemont, Illinois, USA
M. Yadav
The University of Liverpool, Liverpool, United Kingdom
M. Yadav
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was performed with the support of the US Department of Energy, Division of High Energy Physics under Contract No. DE-SC0017648 and DE-SC0009914
In future plasma wakefield acceleration-based scenarios for linear colliders, beams with highly asymmetric emittance are expected. In this case, the blowout region is no longer axisymmetric, but elliptical in cross-section, which implies that the focusing is not equal in the two transverse planes. In this paper, we analyze simulations for studying the asymmetries in flat-beam driven plasma acceleration using the round-to-flat-beam transformer at the Argonne Wakefield Accelerator. Beams with high charge and emittance ratios, in excess of 100:1, are routinely available at the AWA. We use particle-in-cell codes to compare various scenarios including a weak blowout, where the plasma focusing effect exhibits higher order mode asymmetry. Further, practical considerations for tunable plasma density using capillary discharge and laser ionization are compared for implementation into experimental designs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB147

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paper received ※ 20 May 2021 paper accepted ※ 13 July 2021 issue date ※ 02 September 2021

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TUPAB148

Optical-Period Bunch Trains to Resonantly Excite High Gradient Wakefields in the Quasi-Nonlinear Regime and the E-317 Experiment at FACET-II

1736

P. Manwani, C.E. Hansel, N. Majernik, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, California, USA
M. Yadav
The University of Liverpool, Liverpool, United Kingdom
M. Yadav
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was performed with the support of the US Department of Energy under Contract No. DE-SC0009914 and National Science Foundation under Grant No. PHY-1549132
Periodic electron bunch trains spaced at the laser wavelength created via inverse free electron laser (IFEL) bunching can be used to resonantly excite plasmas in the quasi-nonlinear (QNL) regime. The excitation can produce plasma blowout conditions using very low emittance beams despite having a small charge per bunch. The resulting plasma density perturbation is extremely nonlinear locally, but preserves the resonant response of the plasma electrons at the plasma frequency. This excitation can produce plasma blowout conditions using very low emittance beams despite having a small charge per bunch. To match the resonance condition, the plasma wavelength has to be equal to the laser period of a few microns. This corresponds to a high density plasma resulting in extremely large wakefield amplitudes. Matching the beam into such a dense plasma requires an extremely short focusing beta function. We present the beam-plasma interaction using quasi-static particle-in-cell (PIC) simulations and discuss the micro-bunching and focusing mechanism required for this scheme which would be a precursor to the planned experiment, E-317, at SLAC’s FACET-II facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB148

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paper received ※ 20 May 2021 paper accepted ※ 08 July 2021 issue date ※ 19 August 2021

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TUPAB153

Modeling of Capillary Discharge Plasmas for Wakefield Accelerators and Beam Transport

1740

N.M. Cook, J.A. Carlsson, S.J. Coleman, A. Diaw, J.P. Edelen
RadiaSoft LLC, Boulder, Colorado, USA
E.C. Hansen, P. Tzeferacos
Flash Center for Computational Science, Chicago, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0018719.
Next generation accelerators demand sophisticated beam sources to reach ultra-low emittances at large accelerating gradients, along with improved optics to transport these beams without degradation. Capillary discharge plasmas can address each of these challenges. As sources, capillaries have been shown to increase the energy and quality of wakefield accelerators, and as active plasma lenses they provide orders-of-magnitude increases in peak magnetic field. Capillaries are sensitive to energy deposition, heat transfer, ionization dynamics, and magnetic field penetration; therefore, capillary design requires careful modeling. We present simulations of capillary discharge plasmas using FLASH, a publicly-available multi-physics code developed at the University of Chicago. We report on the implementation of 2D and 3D models of capillary plasma density and temperature evolution with realistic boundary and discharge conditions. We then demonstrate laser energy deposition to model channel formation for guiding intense laser pulses. Lastly, we examine active capillary plasmas with varying fill species and compare our simulations against experimental studies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB153

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paper received ※ 24 May 2021 paper accepted ※ 29 July 2021 issue date ※ 30 August 2021

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TUPAB155

Obtaining Accelerated Electron Bunch of High Quality in Plasma Wakefield Accelerator

1744

R.T. Ovsiannikov
KhNU, Kharkov, Ukraine
I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
NSC/KIPT, Kharkov, Ukraine

Funding: "This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299."
Earlier, high-gradient accelerating electrons of a relativistic beam was demonstrated. However, due to dynamic processes in the plasma, there are problems in maintaining the small size and small energy spread of the accelerated electron bunch while maintaining sufficient values of the accelerating wakefields. Also, the question arises about the values of the limiting bunch dimensions at which the accelerating process is stable. To form a stable accelerated electron bunch, a method is usually used that involves the formation of the same accelerating fields at the location of the bunch. The same fields (plateau due to beam loading (see *, **)) in the region of the accelerated bunch allow all its parts to move as a whole, and ensure the preservation of the spatial distribution of electrons over time, which, in fact, means an accelerated beam of good quality. In this report, the problem of electron bunch accelerating by a short or long electron driver-bunch is considered.
* Romeo S., Ferrario M., Rossi A.R. Phys. Rev. Accel. Beams. 23 (2020) 071301.
** Maslov V.I. et al. Problems of Atomic Science and Technology. 6 (2020) 47.

Poster TUPAB155 [1.723 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB155

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paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 23 August 2021

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TUPAB156

Optimal Field Shape, Accelerating Positron Bunch in Plasma Wakefield

1747

R.T. Ovsiannikov
KhNU, Kharkov, Ukraine
I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
NSC/KIPT, Kharkov, Ukraine

Funding: This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299.
The quality of the electron or positron beam, accelerated in plasma accelerators, is still insufficient for applications. Accurate control over the properties of the electron or positron beam is a key issue for wakefield plasma accelerators. The effect of the presence of a witness-beam (the effect of the spatial charge distribution of the witness beam) (see [*, **]) to compensate the energy spread of the positron beam in plasma wakefield accelerators has been studied. This paper presents the results of a numerical simulation on the optimization of the parameters of the driver-bunch and witness-bunch for the formation of a self-consistent longitudinal distribution of the accelerating plateau-type field, which leads to the same values of the wakefield for the whole bunch of accelerated particles and minimizing bunch degradation during acceleration by means of an ion-driver-bunch with external injection into the plasma wake accelerator. The dependence of the longitudinal distribution of the accelerating wakefield on the density and shape of the accelerated bunch in the blowout regime was investigated. Plateau formation and energy spread compensation were observed.
* Romeo S., Ferrario M., Rossi A.R. Phys. Rev. Accel. Beams. 23 (2020) 071301.
** Katsouleas T. et al. Particle Accelerators. 22 (1987) 81.

Poster TUPAB156 [1.200 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB156

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paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 25 August 2021

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TUPAB157

Obtaining Long Accelerated Electron Bunch of Good Quality in Plasma Wakefield Accelerator at High Transformer Ratio

1750

R.T. Ovsiannikov
KhNU, Kharkov, Ukraine
I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
NSC/KIPT, Kharkov, Ukraine

Funding: "This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299."
The efficiency of electron acceleration by a wakefield, excited in a plasma by an electron bunch, is determined by the transformer ratio (see *, **). The transformer ratio is the ratio of energy acquired by the witness to energy lost by the driver. The transformer ratio can be increased by shaping driver-bunch. In this work, using a non-linear version of the 2d3v code lcode (see ***), numerical simulation of excitation of a wakefield in a plasma in blowout regime by a shaped relativistic electron bunch was performed. There is also the problem of maintaining the small dimension and small energy spread of the accelerated electron bunch while maintaining sufficient values of the accelerating gradient and the transformer ratio. Also, the question arises about the values of the limiting dimension of the witness-bunch at which the acceleration process is stable. Numerical simulation solves the problem of electron bunch acceleration of the best quality with simultaneous maximization of the transformer ratio and maximization of the witness bunch length, at which the accelerating gradient and the focusing force are constant.
*Maslov V.I. et al. Problems of Atomic Science and Technology. 4 (2012) 128.
**Baturin S.S., Zholents A. Phys. Rev. ST Accel. Beams. 20 (2017) 061302.
***Lotov K.V. Phys. Plasmas. 5 (1998) 785.

Poster TUPAB157 [1.920 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB157

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paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021

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TUPAB158

Electron Witness Constraints for AWAKE

1753

J.P. Farmer, P. Muggli
MPI-P, München, Germany
E. Gschwendtner
CERN, Meyrin, Switzerland
L. Liang
The University of Manchester, Manchester, United Kingdom
M.S. Weidl
MPI/IPP, Garching, Germany

The AWAKE project at CERN successfully demonstrated the use of a proton driver to accelerate an electron witness in plasma*. One of the key goals for AWAKE Run2 is to better control this acceleration, separating the proton-beam-modulation and electron-acceleration stages in order to achieve high energy electrons with high beam quality. Controlled acceleration additionally requires careful tuning of the witness bunch parameters at the injection point. In this work, we use particle-in-cell simulations to study the tolerances for this matching, and discuss techniques to loosen these constraints.
*Adli et al. (AWAKE Collaboration), Nature (2018)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB158

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 11 August 2021

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TUPAB159

Awake Run 2 at CERN

1757

E. Gschwendtner
CERN, Meyrin, Switzerland

The AWAKE Run 2 experiment, starting in 2021 at CERN, aims to achieve high-charge bunches of electrons accelerated to high energy (~10 GeV) while maintaining beam quality. AWAKE Run 2 also aims to show that the process is scalable so that, by the end of the run, the AWAKE-scheme technology could be used for first particle physics applications. The first two phases of Run 2 include the investigation of the seeding of the proton bunch self-modulation with the current electron beam in the existing AWAKE facility and the test of a second new plasma source with a density step allowing to maintain strong accelerating fields. In the third phase of Run 2, electrons with an energy of 150 MeV, produced in a newly installed electron source, will be injected into a second plasma source and accelerated to high energies (several GeVs) while keeping good emittance. In the fourth phase, it is planned to replace the second plasma source with a scalable one, which eventually could be used for long-distance acceleration and first applications. In this paper, we present the program of the four phases of AWAKE Run 2, the technical challenges and the proposed schedule.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB159

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paper received ※ 17 May 2021 paper accepted ※ 11 June 2021 issue date ※ 19 August 2021

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TUPAB160

Preparation for Electron-Seeding of Proton Bunch Self-Modulation in AWAKE

1761

G. Zevi Della Porta, E. Gschwendtner, L. Verra
CERN, Meyrin, Switzerland
K. Moon
UNIST, Ulsan, Republic of Korea
P. Muggli, L. Verra
MPI, Muenchen, Germany

The next milestone of the Advanced Wakefield Experiment (AWAKE) at CERN will be to demonstrate that the self-modulation of a long proton bunch can be seeded by a short electron bunch preceding it. This seeding method will lead to phase-reproducible self-modulation of the entire proton bunch, as required for the future AWAKE program. In the Spring of 2021, before receiving proton beams from the CERN SPS, AWAKE plans to hold a dry run of the electron seeding experiments, to commission the system and to determine the parameter scans that will be used in experiments with protons. Electron bunches of 10-20 MeV with varying charge, radius, emittance and energy will be sent in 10 m of low-density plasma. The effects of beam-plasma interactions on the amplitude of the wakefields driven by the different bunches will be studied by observing the energy spectra at the end of the plasma. This paper presents preliminary experimental results from the first two days of measurements as well as the beginning of a simulation-based study of electron propagation in plasma.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB160

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 27 August 2021

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TUPAB163

Developing a 50 MeV LPA-Based Injector at ATHENA for a Compact Storage Ring

1765

E. Panofski, J. Dirkwinkel, T. Hülsenbusch, A.R. Maier, J. Osterhoff, G. Palmer, T. Parikh, P.A. Walker, P. Winkler
DESY, Hamburg, Germany
C. Braun, T.F.J. Eichner, L. Hübner, S. Jalas, L. Jeppe, M. Kirchen, P. Messner, M. Schnepp, M. Trunk, C.M. Werle
University of Hamburg, Hamburg, Germany
E. Bründermann, B. Härer, A.-S. Müller, C. Widmann
KIT, Karlsruhe, Germany
M. Kaluza, A. Sävert
HIJ, Jena, Germany

The laser-driven generation of relativistic electron beams in plasma and their acceleration to high energies with GV/m-gradients has been successfully demonstrated. Now, it is time to focus on the application of laser-plasma accelerated (LPA) beams. The "Accelerator Technology HElmholtz iNfrAstructure" (ATHENA) of the Helmholtz Association fosters innovative particle accelerators and high-power laser technology. As part of the ATHENAe pillar several different applications driven by LPAs are to be developed, such as a compact FEL, medical imaging and the first realization of LPA-beam injection into a storage ring. The latter endeavor is conducted in close collaboration between Deutsche Elektronen-Synchrotron (DESY), Karlsruhe Institute of Technology (KIT) and Helmholtz Institute Jena. In the cSTART project at KIT, a compact storage ring optimized for short bunches and suitable to accept LPA-based electron bunches is in preparation. In this conference contribution we will introduce the 50 MeV LPA-based injector and give an overview about the project goals. The key parameters of the plasma injector will be presented. Finally, the current status of the project will be summarized.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB163

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 21 August 2021

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TUPAB166

A New Design of a Dressed Balloon Cavity with Superior Mechanical Properties

1769

R.A. Kostin, C. Jing, S. Ross
Euclid Beamlabs, Bolingbrook, USA
I.V. Gonin, T.N. Khabiboulline, G.V. Romanov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
M.P. Kelly
ANL, Lemont, Illinois, USA
R.E. Laxdal
TRIUMF, Vancouver, Canada

Funding: Work supported by the SBIR program of the U.S. Department of Energy, under grant DE-SC0020781
Superconducting spoke cavities are prone to multipactor - resonant raise of a number of electrons due to secondary emission. Recently proposed and tested by TRIUMF balloon-type spoke cavity showed an outstanding multipactor (MP) suppression property but unfortunately serious Q degradation at high fields. A new fully developed design of a dressed balloon cavity which can be used for any proton linac SSR2 section is developed. The design incorporates additional EP ports for high Q-factor demonstration. Superior properties are demonstrated, such as effective multipactor suppression, 40% lower Lorentz force coefficient, zero sensitivity to external pressure. This paper presents the results of coupled structural Multiphysics analysis, and engineering design of the dressed balloon cavity with EP ports.

Poster TUPAB166 [1.394 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB166

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paper received ※ 15 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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TUPAB167

Status of Conduction Cooled SRF Photogun for UEM/UED

1773

R.A. Kostin, C. Jing
Euclid Beamlabs, Bolingbrook, USA
P.V. Avrakhov, A. Liu, Y. Zhao
Euclid TechLabs, Solon, Ohio, USA

Funding: DOE #DE-SC0018621
Benefiting from the rapid progress on RF photogun technologies in the past two decades, the development of MeV range ultrafast electron diffraction/microscopy (UED and UEM) has been identified as an enabling instrumentation. UEM or UED use low power electron beams with modest energies of a few MeV to study ultrafast phenomena in a variety of novel and exotic materials. SRF photoguns become a promising candidate to produce highly stable electrons for UEM/UED applications because of the ultrahigh shot-to-shot stability compared to room temperature RF photoguns. SRF technology was prohibitively expensive for industrial use until two recent advancements: Nb₃Sn and conduction cooling. The use of Nb₃Sn allows to operate SRF cavities at higher temperatures (4K) with low power dissipation which is within the reach of commercially available closed-cycle cryocoolers. Euclid is developing a continuous wave (CW), 1.5-cell, MeV-scale SRF conduction cooled photogun operating at 1.3 GHz. In this paper, the technical details of the design and first experimental data are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB167

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paper received ※ 29 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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TUPAB168

Beam Commissioning of a 325 MHz Proton IH-DTL at XiPAF

1777

P.F. Ma, X. Guan, R. Tang, M.W. Wang, X.W. Wang, Q.Z. Xing, W.B. Ye, S.X. Zheng
TUB, Beijing, People’s Republic of China
W. Chen, W.L. Liu, W. Lv, M.T. Qiu, B.C. Wang, D. Wang, M.C. Wang, Z.M. Wang, Y.H. Yan, Y. Yang, M.T. Zhao
NINT, Xi’an, People’s Republic of China

The Inter-Digital H-mode Drift Tube Linac (IH-DTL) is widely used as the main component of injectors for medical synchrotrons. This paper describes the beam commissioning of a compact 325 MHz IH-DTL with modified KONUS beam dynamics at Tsinghua University (THU). This IH-DTL accelerates the proton beam from 3 MeV to 7 MeV in 1m. The average energy of the beam is 7.0 MeV with the energy spread range of -0.6 MeV to 0.3 MeV. The output transverse normalized RMS emittance of the beam is 0.58 (x)/0.58 (y) pi mm mrad with the input emittance of 0.43 (x)/0.37 (y) pi mm mrad. The beam test results show good agreement with the beam dynamics design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB168

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paper received ※ 08 May 2021 paper accepted ※ 16 June 2021 issue date ※ 14 August 2021

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TUPAB169

Overall Concept Design of a Heavy-Ion Injector for XiPAF-Upgrading

1781

P.F. Ma, C.T. Du, X. Guan, Y. Lei, M.W. Wang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China
W. Chen, W.L. Liu, W. Lv, M.T. Qiu, B.C. Wang, D. Wang, M.C. Wang, Z.M. Wang, Y.H. Yan, M.T. Zhao
NINT, Xi’an, People’s Republic of China

A heavy-ion injector can be used for SEE study. In this paper, the primary beam dynamics design of a heavy-ion injector for the XiPAF upgrade is presented. The injector consists of an ECR heavy-ion source, a LEBT, an RFQ, and a DTL. The mass charge ratio can be up to 6.5. The RFQ can accelerate heavy ions to 500 keV/u, and the DTL can accelerate the ions to 2 MeV/u, which can meet the requirement of the synchrotron.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB169

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paper received ※ 16 May 2021 paper accepted ※ 16 June 2021 issue date ※ 11 August 2021

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TUPAB170

Decouple Transverse Coupled Beam in the DTL with Tilted PMQs

1785

P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China
Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang
Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China

The coupling of the beam is widely studied in the accelerator physics field. Projected transverse emittances easily grow up if the beam is transversely-coupled. If we decouple the transverse coupled beam, the transverse emittance can be small. The matrix approach based on the symplectic transformation theory for decoupling the coupled beam is summarized. For a proton accelerator, the transverse coupled beam is introduced by an RFQ tilted by 45°. The beam is decoupled with the first five tilted quadrupoles mounted in the DTL section. A study on the gradient choice of the quadrupoles and the space charge effect is given in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB170

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paper received ※ 08 May 2021 paper accepted ※ 21 June 2021 issue date ※ 28 August 2021

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TUPAB171

Linear Transfer Matrix of a Half Solenoid

1789

P.F. Ma, X. Guan, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China

Solenoid magnets can provide strong transverse focusing to electrons and ions with relatively small energies. For the ECR heavy-ion source, the ions are extracted at the central area of the solenoid, the beam is coupled at the exit of the source. The coupling caused by the solenoids can lead to the growth of projected transverse emittance, which has been widely studied with great interest. It is important to study the transfer matrix of a half solenoid to study the beam optics in an ECR souce, thus the property of the beam can be given. Based on the transfer matrix calculation, the summary of the linear transfer matrix of a half solenoid can be given. The beam optics in a half solenoid is studied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB171

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paper received ※ 18 May 2021 paper accepted ※ 28 June 2021 issue date ※ 29 August 2021

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TUPAB172

Quadrupole Magnet Design for a Heavy-Ion IH-DTL

1793

P.F. Ma, C.T. Du, X. Guan, M.W. Wang, X.W. Wang, Y.L. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China
W. Chen, W.L. Liu, W. Lv, M.T. Qiu, B.C. Wang, D. Wang, M.C. Wang, Z.M. Wang, Y.H. Yan, M.T. Zhao
NINT, Xi’an, People’s Republic of China

Xi’an Proton Application Facility (XiPAF) will be upgraded to provide heavy-ion beams with a heavy-ion injector. The injector consists of an ECR heavy-ion source, a Low Energy Beam Transport line (LEBT), a Radio Frequency Quadrupole (RFQ), an Interdigital H-mode Drift Tube Linac (IH-DTL), and a Linac to Ring Beam Transport line (LRBT). The IH-DTL can accelerate the ions with mass to charge up to 6.5 from 0.4 MeV/u to 2 MeV/u. To provide transverse focusing, the electro-magnetic quadrupoles are installed inside the drift tubes of IH-DTL, thus the magnet needs to be high-gradient and compact. This paper gives the quadrupole magnet design for the heavy-ion IH-DTL. The results show that the quadrupole magnet design can meet the requirements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB172

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paper received ※ 08 May 2021 paper accepted ※ 21 June 2021 issue date ※ 23 August 2021

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TUPAB173

ESS Drift Tube Linac Manufacturing, Assembly and Tuning

1797

F. Grespan, L. Antoniazzi, A. Baldo, C. Baltador, A. Battistello, L. Bellan, P. Bottin, M. Comunian, D. Conventi, E. Fagotti, L. Ferrari, A. Palmieri, R. Panizzolo, A. Pisent, D. Scarpa
INFN/LNL, Legnaro (PD), Italy
R.A. Baron
ESS, Lund, Sweden
T. Bencivenga, P. Mereu, C. Mingioni, M. Nenni, E. Nicoletti
INFN-Torino, Torino, Italy
A.G. Colombo
INFN- Sez. di Padova, Padova, Italy
B. Jones
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The Drift Tube Linac (DTL) for the ESS Linac will accelerate H⁺-beams of up to 62.5 mA peak current from 3.62 to 90 MeV. The structure consists of five cavities. The first cavity (DTL1) is a 7.6 m long tank containing 60 drift tubes, 23 fixed tuners, 3 movable tuners and 24 post-couplers, operating at a frequency of 352.21 MHz and an average accelerating field of 3.0 MV/m. The cavity is now assembled at ESS, the results of alignment and tuning are here presented. The DTL1 "as-built" as been analyzed from the beam dynamics point of view. The manufacturing of DTL4 and DTL3 is completed and they are now under assembly at ESS. DTL2 and DTL5 manufacturing will be completed within 2021. The paper describes the production and assembly stages, with a focus on the statistics of quality check in terms of metrology, alignment, leak tests.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB173

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 14 August 2021

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TUPAB174

Basic Design Study for Disk-Loaded Structure in Muon LINAC

1801

K. Sumi, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Ego, T. Mibe, M. Yoshida
KEK, Ibaraki, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
M. Otani, N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Takeuchi
Kyushu University, Fukuoka, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

The world’s first disk-loaded structure (DLS) at the high-velocity part of a muon LINAC is under development for the J-PARC muon g-2/EDM experiment. We have simulated the first designed constant impedance DLS to accelerate muons from ß = 0.7 to 0.94 at an operating frequency of 1296 MHz and a phase of -10 degrees to ensure longitudinal acceptance and have shown the quality of the beam meets our requirements. Because the structure needs a high RF power of 80 MW to generate a gradient of 20 MV/m, a constant gradient DLS with the higher acceleration efficiency is being studied for lower operating RF power. In this poster, we will show the cell structure design yielding a gradient of 20 MV/m with lower RF power.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB174

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paper received ※ 19 May 2021 paper accepted ※ 31 August 2021 issue date ※ 18 August 2021

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TUPAB175

ESSnuSB Linac and Transfer Line: Lattice Design and Error Studies

1805

N. Blaskovic Kraljevic, M. Eshraqi, B.T. Folsom
ESS, Lund, Sweden

Funding: ESSnuSB has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 777419.
The ESS neutrino superbeam (ESSnuSB) project is being studied as an upgrade to the European Spallation Source (ESS). This proposed upgrade consists of adding an H⁻ source to the existing beamline in order to send H⁻ pulses in between proton pulses, effectively doubling the beam power from 5 MW to 10 MW. In this contribution, we present the 2.5 GeV linear accelerator (linac) lattice and the design of the transfer line from the linac to the accumulator ring, where pulses would be stacked to achieve short proton pulses of high intensity. The results of error studies, quantifying the effect of accelerator imperfections and H⁻ ion stripping losses on the beam transport through the linac and transfer line, are also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB175

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 31 August 2021

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TUPAB176

ESS Proton Beam Trajectory Correction

1809

N. Blaskovic Kraljevic, M. Eshraqi, N. Milas, R. Miyamoto
ESS, Lund, Sweden

The proton linac of the European Spallation Source (ESS) is under construction in Lund, Sweden. Beam trajectory correction is essential to mitigate the effect of accelerator element misalignment, constituting the first step to minimise beam losses. The correction will be performed using correctors distributed along the accelerator, based on the beam position monitor (BPM) readout. Three trajectory correction techniques are considered: one-to-one steering, Singular Value Decomposition (SVD), and MICADO (selecting a subset of correctors for the trajectory correction). The performance of the three methods is simulated for the ESS linac and a comparison of the outcomes is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB176

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 27 August 2021

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TUPAB177

Simulating Magnetized Electron Cooling for EIC with JSPEC

1813

S.J. Coleman, D.L. Bruhwiler, B. Nash, I.V. Pogorelov
RadiaSoft LLC, Boulder, Colorado, USA
H. Zhang
JLab, Newport News, Virginia, USA

We present a possible electron cooling configuration for the proposed Electron Ion Collider (EIC) facility, developed using a Nelder-Mead Simplex optimization procedure built into JSPEC, an electron cooling code developed at Jefferson Lab. We show the time evolution of the emittance of the ion beam in the presence of this cooler evaluated assuming the ion distribution remains Gaussian. We also show that bi-gaussian distributions emerge in simulations of ion macro-particles. We show how intra-beam scattering can be treated with a core-tail model in simulations of ion macro-particles. The Sirepo/JSPEC* and Sirepo/Jupyter** apps will be presented, with instructions enabling the community to reproduce our simulations.
* https://www.sirepo.com/jspec
** https://www.sirepo.com/jupyter

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB177

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 16 August 2021

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TUPAB178

Recommissioning of the CRYRING@ESR Electron Cooler

1816

C. Krantz, Z. Andelkovic, C. Dimopoulou, W. Geithner, T. Hackler, F. Herfurth, R. Hess, M. Lestinsky, E. Menz, A. Reiter, J. Roßbach, C. Schroeder, A. Täschner, G. Vorobjev
GSI, Darmstadt, Germany
C. Brandau, S. Schippers
Justus-Liebig-University Giessen, I. Physics Institute, Atomic and Molecular Physics, Giessen, Germany
V. Hannen, D. Winzen
Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany
C. Weinheimer
Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany

Funding: Parts of this work have been supported by the German Federal Ministry of Education and Research (BMBF) under contract numbers 05P19PMFA1 and 05P19RGFA1.
The heavy-ion storage ring CRYRING has been recommissioned downstream of GSI’s ESR, which it complements as dedicated low-energy machine. A key element of CRYRING@ESR is its electron cooler, which features one of the coldest electron beams available. This enables efficient phase-space cooling and, in addition, provides very high energy resolution when used as internal electron target. We report on technical upgrades that have been made as part of the re-installation of the cooler at GSI/FAIR and share first results obtained after recommissioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB178

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paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 25 August 2021

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TUPAB179

Design of an MBEC Cooler for the EIC

1819

W.F. Bergan, P. Baxevanis, M. Blaskiewicz, E. Wang
BNL, Upton, New York, USA
G. Stupakov
SLAC, Menlo Park, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Reaching maximal luminosity for the planned electron-ion collider (EIC) calls for some form of strong hadron cooling to counteract beam emittance increase from IBS. We discuss plans to use microbunched electron cooling (MBEC) to achieve this. The principle of this method is that the hadron beam will copropogate with a beam of electrons, imprinting its own density modulation on the electron beam. These electron phase space perturbations are amplified before copropogating with the hadrons again in a kicker section. By making the hadron transit time between modulator and kicker dependent on hadron energy and transverse offset, the energy kicks which they receive from the electrons will tend to reduce their longitudinal and transverse emittances. We discuss details of the analytic theory and searches for optimal realistic parameter settings to achieve a maximal cooling rate while limiting the effects of diffusion and electron beam saturation. We also place limits on the necessary electron beam quality. These results are corroborated by simulations.

Poster TUPAB179 [4.006 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB179

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 24 August 2021

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TUPAB180

Plasma Simulations for an MBEC Cooler for the EIC

1823

W.F. Bergan
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
In order to reach its maximum luminosity, the electron-ion collider (EIC) is being designed to use microbunched electron cooling (MBEC) to cool the hadron beam. This involves having the hadron beam imprint on a beam of electrons, enhancing the perturbations in the electron beam using the microbunching instability, and feeding back on the original hadron beam to correct deviations in hadron energy, and, through the use of dispersion, the transverse emittances. This process has been modelled analytically in the linear regime*. However, in order to maximize the cooling rate, we wish to know how much saturation in the electron beam is acceptable before the effects of nonlinearity cause significant deviations from the analytic results. To understand this, we have developed a code to do fast one-dimensional plasma simulations of hadrons and electrons as they move through the MBEC section of the EIC. In addition to permitting us to understand the effects of saturation, other effects are included which do not fit easily in the analytic formalism.
* G. Stupakov and P. Baxevanis, PRAB 22, 034401 (2019).

Poster TUPAB180 [1.955 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB180

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 18 August 2021

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TUPAB181

Demonstration of Electron Cooling using a Pulsed Beam from an Electrostatic Electron Cooler

1827

M.W. Bruker, S.V. Benson, A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, T. Satogata, A.V. Sy, H. Wang, S. Wang, H. Zhang, Y. Zhang
JLab, Newport News, Virginia, USA
J. Li, F. Ma, X.M. Ma, L.J. Mao, X.P. Sha, M.T. Tang, J.C. Yang, X.D. Yang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China
H. Zhao
BNL, Upton, New York, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Electron cooling continues to be an invaluable technique to reduce and maintain the emittance in hadron storage rings in cases where stochastic cooling is inefficient and radiative cooling is negligible. Extending the energy range of electron coolers beyond what is feasible with the conventional, electrostatic approach necessitates the use of RF fields for acceleration and, thus, a bunched electron beam. To experimentally investigate how the relative time structure of the two beams affects the cooling properties, we have set up a pulsed-beam cooling device by adding a synchronized pulsing circuit to the conventional electron source of the CSRm cooler at Institute of Modern Physics *. We show the effect of the electron bunch length and longitudinal ion focusing strength on the temporal evolution of the longitudinal and transverse ion beam profile and demonstrate the detrimental effect of timing jitter as predicted by theory and simulations. Compared to actual RF-based coolers, the simplicity and flexibility of our setup will facilitate further investigations of specific aspects of bunched cooling such as synchro-betatron coupling and phase dithering.
* M. W. Bruker et al., Phys. Rev. Accel. Beams 24, 012801 (2021)

Poster TUPAB181 [3.699 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB181

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021

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TUPAB182

The Electron Cooling for High Energy

1831

V.B. Reva, E.A. Bekhtenev, O.V. Belikov, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, A.P. Denisov, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.C. Gosteyev, I.A. Gusev, G.V. Karpov, M.N. Kondaurov, V.R. Kozak, N.S. Kremnev, V.M. Panasyuk, V.V. Parkhomchuk, A.V. Petrozhitskii, D.N. Pureskin, A.A. Putmakov, D.V. Senkov, K.S. Shtro, D.N. Skorobogatov, R.V. Vakhrushev, A.A. Zharikov
BINP SB RAS, Novosibirsk, Russia

The project of new accelerator complex NICA relating to nuclear and hadron physics require a more powerful longitudinal and transverse cooling that stimulates searching new technical solutions. The new accelerator complex NICA is designed at the Joint Institute for Nuclear Research (JINR, Dubna, Russia) to do experiment with ion-ion and ion-proton collision in the energy range 1-4.5 GeV/u for studying the properties of dense baryonic matter at extreme values of temperature and density with planned luminosity 10²⁷ cm^-2s^-1. This value can be obtained with help of very short bunches with small transverse size. This beam quality can be realized with help of stochastic and electron cooling at energy of the physics experiment. The electron cooling system on 2.5 MeV consists of two coolers, which cool both ion beams simultaneously. The Budker Institute of Nuclear Physics (BINP SB RAS) has already built and commissioned the electron cooling system for the NICA booster, and now it develops the high voltage electron cooling system for the collider. The article describes the construction and status of the cooler development.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB182

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paper received ※ 18 May 2021 paper accepted ※ 22 June 2021 issue date ※ 11 August 2021

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TUPAB186

Longitudinal Dynamics in the Prototype vFFA Ring for ISIS2

1834

D.J. Kelliher, J.-B. Lagrange, S. Machida, C.R. Prior, C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
A.P. Letchford, J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
E. Yamakawa
JAI, Egham, Surrey, United Kingdom

A vertical Fixed Field Accelerator (vFFA) is a candidate for a future high-power (MW-class) spallation source at ISIS. In order to assess the feasibility of this novel ring, a prototype is currently being designed. Here we consider the longitudinal dynamics in the prototype ring. A key requirement of future neutron spallation sources is flexibility of operation to best serve multiple target stations. Beam stacking allows a rapid cycling, high intensity machine to operate at lower repetition rates but with higher peak output. Here we show how beam stacking can be realised in the vFFA while minimising the peak RF voltage required.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB186

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 23 August 2021

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TUPAB187

Reconstruction of U400M Cyclotron: Upgrade of U400M Cyclotron Magnetic Structure

1838

I.A. Ivanenko, G.G. Gulbekyan, I.V. Kalagin, N.Yu. Kazarinov, N.F. Osipov, V.A. Semin
JINR, Dubna, Moscow Region, Russia

U400M isochronous cyclotron was created on the base of U300 classic cyclotron and is under operation at FLNR, JINR since 1996. At the present time the cyclotron electromagnet with 4 meter pole diameter needs a reconstruction that includes a replacement of magnet main coil, corrections of the magnetic field at the central region and at the extraction radius. For measurements and shimming of cyclotron magnetic field the automatic mapping system, based on 14 Hall probes, will be created.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB187

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paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 20 August 2021

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TUPAB188

InnovaTron: An Innovative High-Intensity Industrial Cyclotron for Production of Tc-99m and Other Frontier Medical Radioisotopes*

1841

G. D’Agostino, Q. Flandroy, E. Forton, W.J.G.M. Kleeven, J. Mandrillon, V. Nuttens, E. van der Kraaij
IBA, Louvain-la-Neuve, Belgium

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 886190.
Tc-99m is the most used radioisotope in nuclear medicine. It is almost exclusively produced with a few ageing research reactors worldwide. In response to growing concerns about Tc-99m availability and its increasing demand, alternative production routes are being explored. The EU-funded InnovaTron project aims at designing an innovative compact high-intensity self-extracting cyclotron able to deliver proton beams with currents up to 5 mA or more for the direct production of Tc-99m. It could be also used for production of high quantities of other frontier medical radioisotopes. The proton beams exit without using an electrostatic deflector to overcome its current limitations. A prototype cyclotron was built by IBA in 2001. Currents up to 2 mA were extracted from it. However, at higher intensities, the extraction efficiency was not higher than 70-75% and the extracted emittance was rather large. The InnovaTron project will implement new technological solutions in the self-extracting cyclotron to be used for large-scale industrial applications. An overview on the InnovaTron project is here presented together with the first simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB188

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paper received ※ 18 May 2021 paper accepted ※ 01 June 2021 issue date ※ 25 August 2021

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TUPAB189

Design and Simulation of Beam Transport Lines of DC140 Cyclotron

1845

V.I. Lisov, N.S. Kirilkin, A.S. Zabanov
JINR/FLNR, Moscow region, Russia
I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, V.A. Semin
JINR, Dubna, Moscow Region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The beam transport system has three lines: for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The design and simulation of the beam transport system from cyclotron is presented in this report. The beam focusing in the beam lines is provided by set of quadrupole lenses. The beam diagnostics system consists of the Faraday caps, luminophores and the magnetic scanning system.

Poster TUPAB189 [0.958 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB189

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paper received ※ 14 May 2021 paper accepted ※ 02 June 2021 issue date ※ 17 August 2021

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TUPAB190

Design and Simulation of the Extraction System of DC140 Cyclotron

1849

V.I. Lisov, A.A. Protasov, A.S. Zabanov
JINR/FLNR, Moscow region, Russia
K. Gikal, G.G. Gulbekyan, I.A. Ivanenko, G.N. Ivanov, I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, N.F. Osipov, V.A. Semin
JINR, Dubna, Moscow Region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The system based on four main elements - electrostatic deflector, focusing magnetic channel, Permanent Magnet Quadrupole lens and steering magnet is used in the DC140 cyclotron for extraction of the accelerated beam. The design and simulation of the beam extraction system from the DC140 cyclotron are presented in this report.

Poster TUPAB190 [1.102 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB190

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 25 August 2021

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TUPAB191

Design and Simulation of the Axial Injection Beam Line of DC140 Cyclotron of FLNR JINR

1852

N.Yu. Kazarinov, V. Bekhterev, G.G. Gulbekyan, I.A. Ivanenko, I.V. Kalagin, S.V. Mitrofanov, N.F. Osipov, V.A. Semin
JINR, Dubna, Moscow Region, Russia
V.I. Lisov
JINR/FLNR, Moscow region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The main systems of DC140 are based on the DC72 cyclotron ones that now are under reconstruction. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The injection into cyclotron will be realized from the external room temperature 18 GHz ECR ion source. The design and simulation of the axial injection system of the DC140 cyclotron is presented in this report.

Poster TUPAB191 [1.090 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB191

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paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 22 August 2021

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TUPAB192

Studies on Momentum Collimation for CSNS-RCS Upgrades

1855

Y.W. An, J. Chen, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China
X.H. Lu, J.B. Yupresenter
IHEP CSNS, Guangdong Province, People’s Republic of China

The CSNS project was a high intensity pulsed facility, and achieved the the design goal of 100kW in 2020. The upgrades of the CSNS are proposed, and the momentum collimator is a component of the upgrades. This paper will show the design scheme of the momentum collimator and the simulation results are also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB192

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 28 August 2021

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TUPAB193

Operation and Maintenance of Chinese Spallation Neutron Source Stripper Foil

1858

J.X. Chen, X.J. Nie, A.X. Wang, Y.J. Yu
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Kang, L. Liu
IHEP, Beijing, People’s Republic of China
J.B. Yu
DNSC, Dongguan, People’s Republic of China

Funding: The project is supported by the National Natural Science Foundation of China (Grant No.11975253) and Natural Science Foundation of Guangdong Province (Grant No.2018A030313959)
The stripper foil system is the essential equipment of the spallation neutron source to achieve negative hydrogen injection. More than 99% of negative hydrogen ions complete the charge stripper in the primary stripper foil during the injection process. The remaining ions will lead to the in-dump after the secondary foil or absorbed by the negative hydrogen scraper. This paper introduces some work records of operation and maintenance of stripper foil system.
stripper foil, maintenance, operation

Poster TUPAB193 [0.395 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB193

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paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021

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TUPAB194

Operation Status of CSNS/RCS Transverse Collimation System

1862

J.B. Yu, J.X. Chen, L. Liu, X.J. Nie, C.J. Ning, G.Y. Wang, A.X. Wang, J.S. Zhang
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Kang, Q.B. Wu, S.Y. Xu
IHEP, Beijing, People’s Republic of China

Funding: Natural Science Foundation of Guangdong Province 2018A030313959
In order to meet the requirements of daily maintenance of CSNS/RCS, the transverse collimation system was designed to concentrate the uncontrollable beam loss in this region. Based on physical parameters, considering the processing technology, the area was rationally arranged; combined with the requirements of physical and radiation protection, under the premise of meeting the use requirements, fully consider the limit switch, mechanical hard limit and other components, increasing the output control signals of rotary encoder and displacement sensor, the movement of the absorbers were monitored. At present, the beam collimation system has been running with no mechanical failure for two years on CSNS, and it plays an active role in beam power boost and beam loss control, which proves that the structural design of the system is reasonable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB194

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paper received ※ 17 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021

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TUPAB195

Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning

1865

Y.W. An, Y. Li, S.Y. Xupresenter, Y. Yuan
IHEP, Beijing, People’s Republic of China
M.T. Li
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.

Poster TUPAB195 [2.279 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195

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paper received ※ 13 May 2021 paper accepted ※ 17 June 2021 issue date ※ 01 September 2021

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TUPAB196

Achievement of 100-kW Beam Operation in CSNS/RCS

1869

S.Y. Xu, Y.W. An, J. Chen, L. Huang, M.Y. Huang, Y. Li, S. Wang
IHEP, Beijing, People’s Republic of China
H.Y. Liu, X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron(RCS). The RCS accumulates and accelerates the proton beam to 1.6 GeV and then extracts the beam to the target at the repetition rate of 25 Hz. The Beam commissioning of CSNS/RCS had been started since April 2017. The most important issue in high-power beam commissioning is the beam loss control, as well as the control of induced activities, to meet the requirement of manual maintenance. A series of beam loss optimization work had been done to reduce the uncontrolled beam loss. At the end of February 2020, the CSNS reached the design beam power of 100 kW with very low uncontrolled beam loss.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB196

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021

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TUPAB198

ESS DTL Tuning Using Machine Learning Methods

1872

J.S. Lundquist, N. Milas, E. Nilsson
ESS, Lund, Sweden
S. Werin
Lund University, Lund, Sweden

The European Spallation Source, currently under construction in Lund, Sweden, will be the world’s most powerful neutron source. It is driven by a proton linac with a current of 62.5 mA, 2.86 ms long pulses at 14 Hz. The final section of its normal-conducting front-end consists of a 39 m long drift tube linac (DTL) divided into five tanks, designed to accelerate the proton beam from 3.6 MeV to 90 MeV. The high beam current and power impose challenges to the design and tuning of the machine and the RF amplitude and phase have to be set within 1% and 1 degree of the design values. The usual method used to define the RF set-point is signature matching, which can be a time consuming and challenging process, and new techniques to meet the growing complexity of accelerator facilities are highly desirable. In this paper we study the usage of Machine Learning to determine the RF optimum amplitude and phase. The data from a simulated phase scan is fed into an artificial neural network in order to identify the needed changes to achieve the best tuning. Our test for the ESS DTL1 shows promising results, and further development of the method will be outlined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB198

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paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 13 August 2021

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TUPAB199

Progress on the Proton Power Upgrade at the Spallation Neutron Source

1876

M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White
ORNL, Oak Ridge, Tennessee, USA
E. Daly
JLab, Newport News, Virginia, USA
N.J. Evans, G.D. Johns
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199

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paper received ※ 10 May 2021 paper accepted ※ 28 May 2021 issue date ※ 21 August 2021

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TUPAB200

Status of the Electron Lens for Space Charge Compensation in SIS18

1880

K. Schulte-Urlichs, S. Artikova, D. Ondreka, P.J. Spiller
GSI, Darmstadt, Germany
P. Apse-Apsitis, I. Steiks
Riga Technical University, Riga, Latvia
M. Droba, O. Meusel, H. Podlech, K.I. Thoma
IAP, Frankfurt am Main, Germany

At GSI a project has been initiated to investigate the option of space charge compensation (SCC) by use of an electron lens in order to overcome space charge (SC) limits in the synchrotrons SIS18 and SIS100 for the Facility for Antiproton and Ion Research (FAIR). The repeated crossing of resonance lines due to the synchrotron motion in bunched beams is considered one of the main drivers of SC induced beam loss in the synchrotrons. Electron lenses provide a compensation of ion beam SC by virtue of their negative charge interacting with the ions in the overlap region while a time-varying compensation can be achieved by the modulation of the electron beam. In order to demonstrate space charge compensation of bunched ion beams, an electron lens is under development for the application in SIS18. In this contribution, the status of the electron lens design will be reported putting special emphasis on its main components: the RF modulated electron gun, that is being developed within an ARIES collaboration, and the magnet system.

Poster TUPAB200 [1.869 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB200

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 17 August 2021

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TUPAB201

Vacuum Tube Operation Tuning for a High Intensity Beam Acceleration in J-PARC RCS

1884

M. Yamamoto, M. Nomura, H. Okita, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

Tetrode vacuum tubes in the J-PARC RCS are used under a reduced filament voltage condition compared with the rating value to prolong the tube life time. One tube reached the end of life in 2020; it was the first case in the RCS after 60,000 hours operation time. This means the reduced filament voltage works well because the tube has been running beyond an expected life time suggested by the tube manufacturer. However, an electron emission from the filament is decreased by the reduced filament voltage. Although the large amplitude of the anode current is necessary for the high intensity beam acceleration to compensate an wake voltage, a solid-state amplifier to drive a control grid circuit almost reaches the output power limit because of the poor electron emission. We changed the filament voltage reduction rate from 15 % to 5 %; the required power of the solid-state amplifier was fairly reduced, whereas the accelerated beam power was same. We will describe the measurement results of the vacuum tube parameters in terms of the filament voltage tuning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB201

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paper received ※ 17 May 2021 paper accepted ※ 17 June 2021 issue date ※ 02 September 2021

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TUPAB203

Electromagnetic Simulations of a Novel Proton Linac Using VSim on HPC

1887

S.I. Sosa Guitron, S. Biedron, T.B. Bolin
UNM-ECE, Albuquerque, USA
J.R. Cary
Tech-X, Boulder, Colorado, USA
M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson
Ion Linac Systems, Inc., Albuquerque, USA

Funding: This work is supported by the U.S. Department of Energy, award number DE-SC0019468; It used resources of the Argonne Leadership Computing Facility, contract DE-AC02-06CH11357, and from Element Aero.
We discuss electromagnetic simulations of accelerating structures in a high performance computing (HPC) system. Our overarching goal is to resolve the linac operation in a large ensemble of initial beam conditions. This requires a symbiotic relation between the electromagnetic solver and HPC. The linac is being developed by Ion Linac Systems to produce a low-energy, high-current, proton beam. We use VSim, an electromagnetic solver and PIC software developed by Tech-X to determine the electromagnetic fundamental mode of operation of the accelerating structures and discuss its implementation at the THETA supercomputer in the Argonne Leadership Computing Facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB203

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paper received ※ 20 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021

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TUPAB204

Upgrade of Los Alamos Accelerator Facility as a Fusion Prototypic Neutron Source

1890

Y.K. Batygin, E.J. Pitcher
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract 89233218CNA000001
The Fusion Prototypic Neutron Source (FPNS) is considered to be a testbed for scientific understanding of material degradation in future nuclear fusion reactors. The primary mission of FPNS is to provide a damage rate in samples of 8-11 dpa/calendar year with He/dpa ratio of 10 appm in irradiation volume of 50 cubic cm or larger with irradiation temperature 300-1000 deg C and flux gradient less than 20%/cm in the plane of the sample. Los Alamos Neutron Science Center (LANSCE) is an attractive candidate for FPNS project. Accelerator Facility was designed and operated for an extended period as a 0.8-MW Meson Factory. Existing setup of the LANSCE accelerator complex can nearly fulfill requirements of the fusion neutron source station. The primary function of the upgraded accelerator systems is the safe and reliable delivery of a 1.25-mA continuous proton beam current at 800-MeV beam energy from the switchyard to the target assembly to create 1 MW power of proton beam interacting with a solid tungsten target. The present study describes existing accelerator setup and further development required to meet the needs of FPNS project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB204

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paper received ※ 14 May 2021 paper accepted ※ 02 June 2021 issue date ※ 21 August 2021

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TUPAB205

Advancement of LANSCE Front End Accelerator Facility

1894

Y.K. Batygin, D. Gorelov, S.S. Kurennoy, J.W. Lewellen, N.A. Moody, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract 89233218CNA000001
The LANSCE accelerator started routine operation in 1972 as a high-power facility for fundamental research and national security applications. To reduce long-term operational risk, we propose to develop a new Front End of accelerator facility. It contains 100-keV injector with 3-MeV RFQ, and 6-tanks Drift Tube Linac to accelerate particles up to energy of 100 MeV. The low-energy injector concept includes two independent transports merging H⁺ and H⁻ beams at the entrance of RFQ. Beamlines are aimed to perform preliminary beam bunching in front of accelerator section with subsequent simultaneous acceleration of two different beams in a single RFQ. The paper discusses design topics of new Front End of accelerator facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB205

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paper received ※ 12 May 2021 paper accepted ※ 28 May 2021 issue date ※ 14 August 2021

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TUPAB206

Matching of Intense Beam in Six-Dimensional Phase Space

1897

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract 89233218CNA000001
Beam matching is a common technique that is routinely employed in accelerator design to minimize beam losses. Despite being widely used, a full theoretical understanding of beam matching in 6D phase space remains elusive. Here, we present an analytical treatment of 6D beam matching of a high-intensity beam onto an RF structure. We begin our analysis within the framework of a linear model, and apply the averaging method to attain a matched solution for a set of 3D beam envelope equations. We then consider the nonlinear regime, where the beam size is comparable with the separatrix size. Starting with a Hamiltonian analysis in 6D phase space, we attain a self-consistent beam profile and show that it is significantly different from the commonly used ellipsoidal shape. Subsequently, we analyze the special case of equilibrium with equal space charge depression between all degrees of freedom. A comparison of beam dynamics for equipartitioned, equal space charge depression, and equal emittances beams is given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB206

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paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 24 August 2021

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TUPAB208

FETS-FFA Ring Study

1901

J.-B. Lagrange, D.J. Kelliher, A.P. Letchford, S. Machida, C.R. Prior, C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.J. Brooks
BNL, Upton, New York, USA
C. Brown
Brunel University, Middlesex, United Kingdom
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
E. Yamakawa
JAI, Egham, Surrey, United Kingdom

ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, providing a proton beam with a power of 0.2~MW. Detailed studies are under way for a major upgrade, including the use of Fixed Field alternating gradient Accelerator (FFA). A proof-of-principle FFA ring, called FETS-FFA is planned to investigate the feasibility of this kind of machine for the required MW beam power. This paper discusses the study of the FETS-FFA ring case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB208

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paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 14 August 2021

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TUPAB209

The Particle Tracking Code Fixfield

1905

J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021

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TUPAB210

Construction Status of the COMET Experimental Facility

1907

Y. Fukao, K. Agari, H. Akiyama, E. Hirose, M. Ieiri, Y. Igarashi, M.I. Iio, N. Kamei, Y. Katoh, Y. Komatsu, R. Kurasaki, M. Maki, S. Makimura, S. Mihara, M. Minakawa, Y. Morino, F. Muto, H. Nishiguchi, T. Okamura, K. Sasaki, Y. Sato, S. Sawada, N. Sumi, H. Takahashi, K.H. Tanaka, A. Toyoda, K. Ueno, H. Watanabe, Y. Yamanoi, M.Y. Yoshida
KEK, Tsukuba, Japan

COMET (COherent Muon to Electron Transition) is an experimental project that hunts for a phenomenon of the conversion from the muon to the electron (mu-e conversion). The mu-e conversion violates the lepton flavor universality and its discovery indicates a proof of the physics beyond the standard model of the particle physics. The experiment utilizes a high-intensity primary proton-beam of J-PARC (Japan Proton Accelerator Research Complex). The proton beam is injected to a target about 700mm long to generate a high intensity muon beam so as to accumulate huge statistics and achieve the final goal of a sensitivity of 10^-16. Construction of the experimental facility is underway at a high pace towards an engineering run in 2022 and the first physics run in 2023. In this presentation, we would like to present a current status of the COMET facility construction.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB210

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paper received ※ 17 June 2021 paper accepted ※ 21 June 2021 issue date ※ 13 August 2021

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TUPAB211

The Accelerator System of IFMIF-DONES Multi-MW Facility

1910

I. Podadera, A. Ibarra, D. Jimenez-Rey, J. Mollá, C. Oliver, D. Regidor, R. Varela, C. de la Morena
CIEMAT, Madrid, Spain
F. Arbeiter, V. Hauer
KIT, Eggenstein-Leopoldshafen, Germany
N. Bazin, J. Dumas, L. Seguí
CEA-IRFU, Gif-sur-Yvette, France
L. Bellan, E. Fagotti, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
N. Chauvin, S. Chel, J. Plouin
CEA-DRF-IRFU, France
G. Duglue, H. Dzitko
F4E, Germany
W.C. Grabowski, A. Wysocka-Rabin
NCBJ, Świerk/Otwock, Poland
M. Jaksic, T. Tadic
RBI, Zagreb, Croatia
W. Królas
IFJ-PAN, Kraków, Poland
R. López, A. Muñoz, C. Prieto
Empresarios Agrupados, Madrid, Spain
O. Nomen, M. Sanmartí, F.J. Saura Esteban, B.K. Singh, D. Sánchez-Herranz
IREC, Sant Adria del Besos, Spain

Funding: Work carried out within EUROfusion Consortium and DONES-PreP and received funding from the Euratom research and training programme 2014-2018 & 2019-2020 under grants agreement No. 633053 & 870186
The IFMIF-DONES (DEMO-Oriented Neutron Early Source) facility has passed the preliminary design phase and the detailed design phase is very much advanced. Next step will be the preparation phase for the construction of the facility. The DONES facility aims at developing a database of fusion-like radiation effects on materials to be used in future fusion reactors up to damage levels expected in the EU DEMO. It will be based on an intense neutron source created by an accelerated deuteron beam (125 mA CW, 40 MeV) impinging on a liquid lithium curtain. The DONES Accelerator Systems (AS) will be responsible of delivering this 5 MW D⁺ beam with very high availability. The beam acceleration will be performed by several stages: an ion source and LEBT, an RFQ, a MEBT, an SRF Linac and a HEBT transporting and delivering an optimized profile down to the target. A high power RF system and several ancillaries will ensure the equipment is properly operated. This contribution will report the present status of the AS design, the main challenges faced, the R&D programme to overcome them, and the prospects for the construction and commissioning of the DONES accelerator in Granada (Spain).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB211

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021

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TUPAB213

Important Drift Space Contributions to Non-Linear Beam Dynamics

1914

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries
HZB, Berlin, Germany

This paper presents an in-depth analysis of the non-linear contributions of drift spaces in beam dynamics for the creation of Transverse Resonance Island Buckets (TRIBs). TRIBs have been successfully generated in BESSY II and MLS at the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB). They offer the possibility of generating a second stable orbit and, by populating the orbit with a different electron bunch pattern, allow to effectively have two distinct radiation sources in the same machine individually tailored to different user needs. We demonstrate the generation of TRIBs by order of non-linearity on simple lattice configurations by only treating the drift space as the non-linear element. Moreover, we also insert other non-linear magnets to show how they modify the already generated TRIBs from the drift spaces. We conclude by giving a qualitative analysis of the occurring effects, which provides a guideline as to when the linear approximation is insufficient and the non-linear contribution has to be taken into account.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB213

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paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 29 August 2021

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TUPAB214

Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis

1917

J. Frank, M. Arlandoo, P. Goslawski, T. Mertens, M. Ries
HZB, Berlin, Germany

At HZB’s BESSY II and MLS facilities we have the ability to tune the momentum compaction factor α up to second non-linear order. The non-linear dependence α(δ) brings qualitative changes to the longitudinal phase space and introduces new fix points α(δ)=0 which produce the so-called α-buckets. We present with this paper an analysis of this phenomena from the standpoint of bifurcation theory. With this approach we were able to characterize the nature of the fix points and their position in direct dependence on the tunable parameters. Furthermore, we are able to place stringent conditions onto the tunable parameters to either create or destroy α-buckets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB214

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paper received ※ 12 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021

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TUPAB215

Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment

1920

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
HZB, Berlin, Germany

With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215

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paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021

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TUPAB216

Modeling Particle Stability Plots for Accelerator Optimization Using Adaptive Sampling

1923

M. Schenk, L. Coyle, T. Pieloni
EPFL, Lausanne, Switzerland
M. Giovannozzi, A. Mereghetti
CERN, Meyrin, Switzerland
E. Krymova, G. Obozinski
SDSC, Lausanne, Switzerland

Funding: This work is partially funded by the Swiss Data Science Center (SDSC), project C18-07.
One key aspect of accelerator optimization is to maximize the dynamic aperture (DA) of a ring. Given the number of adjustable parameters and the compute-intensity of DA simulations, this task can benefit significantly from efficient search algorithms of the available parameter space. We propose to gradually train and improve a surrogate model of the DA from SixTrack simulations while exploring the parameter space with adaptive sampling methods. Here we report on a first model of the particle stability plots using convolutional generative adversarial networks (GAN) trained on a subset of SixTrack numerical simulations for different ring configurations of the Large Hadron Collider at CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB216

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 22 August 2021

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TUPAB217

Effect of Undulators on Transverse Resonant Island Orbits

1927

E.C.M. Rial, J. Bahrdt, P. Goslawski, A. Meseck, M. Ries, M. Scheer
HZB, Berlin, Germany

For one week in October 2020, BESSY II offered a Two Orbit mode to users for the first time*. In this Two Orbit mode, the existence of transverse resonant island buckets** are exploited to store a second beam in the storage ring as an ’island orbit’, away from the primary beam axis. This mode was offered with free range of motion of the 12 out of vacuum undulators installed at the BESSY II ring. Diagnostics of the island orbit were limited to a single camera monitoring bending magnet radiation from a single dipole. A significant motion of the island orbit was observed on this diagnostic and correlated with undulator motion. This observation is reported, and simulations presented to demonstrate how this motion could arise. Correction schemes are suggested and discussed.
*Two Orbit - a report on the first scheduled week of TRIBs user operation at BESSY II, M. Ries et al, these proceedings
**Proc. IPAC 2016, Busan, S Korea, paper THPMR017, p. 3427

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB217

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021

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TUPAB218

Fully Covariant Two-Particle Space-Charge Dynamics Using the Liénard-Wiechert Potentials

1931

B.T. Folsom, E. Laface
ESS, Lund, Sweden

Space charge models typically assume instantaneous propagation of the electromagnetic fields between particles in a bunch, describing forces in the frame of the reference particle. In this paper, we construct a space-charge tracking code from the retarded Liénard-Wiechert potentials, which are covariant by design, in a Lagrangian formulation. Such potentials are manipulated with covariant derivatives to produce the necessary equations of motion that will be solved in a test system of two particles at various relative energies. Magnetic dipole moment dynamics are also evaluated where applicable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB218

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 11 August 2021

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TUPAB219

Equilibrium and Nonlinear Beam Dynamics Parameters From Sirius Turn-by-Turn BPM Data

1935

X.R. Resende, M.B. Alves, L. Liu, F.H. de Sá
LNLS, Campinas, Brazil

A considerable amount of beam information is conveyed by Turn-by-Turn (TbT) data of Beam Position Monitors (BPM). In this work such data sets are analyzed for Sirius, the Brazilian 4th Generation 3GeV synchrotron light source. In particular, equilibrium and non-linear beam dynamics parameters determining decoherence patterns in TbT position data are estimated and compared with corresponding values of the nominal storage ring model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB219

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paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 15 August 2021

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TUPAB220

Longitudinal Dynamics with Harmonic Cavities under the Over-stretching Conditions

1939

J.Y. Xu, H.S. Xu
IHEP, Beijing, People’s Republic of China

Higher harmonic cavities (HHCs) are often used to lengthen the bunches, mainly for increasing the Touschek lifetime or for suppressing the coupled-bunch instabilities in electron storage rings. There have been quite many studies on the beam dynamics with the consideration of HHCs. We revisited the basic longitudinal dynamics with HHCs. The derivation of the longitudinal equations of motion with HHCs will be presented in this paper. The difference in the number of fixed points at different HHC settings (mainly under the over-stretching conditions) is also discussed.

Poster TUPAB220 [1.082 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB220

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 29 August 2021

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TUPAB222

Application and Development of the Streak Camera Measurement System at HLS-II

1942

Y.K. Zhao, S.S. Jin, P. Lu, B.G. Sun, J.G. Wang, F.F. Wu, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The dual-axial scan streak camera plays an important role in the super-fast optical measurement and the beam diagnosis of the accelerators. Indeed, the development of the synchrotron light measurement system by virtue of the streak camera provides an effective tool and research platform for accelerator physics and super-fast optical phenomenon. In this paper, the configuration of the streak camera measurement system is roughly described. And the experimental researches are simultaneously performed, including the bunch lengthening, the potential-well distortion, the longitudinal bunch oscillations, and the beam evolution during the single bunch operation mode in the HLS-II storage ring. Moreover, the effects of the RF modulation on the beam lifetime and longitudinal bunch beam dynamics are carried out.

Poster TUPAB222 [1.713 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB222

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paper received ※ 10 May 2021 paper accepted ※ 16 June 2021 issue date ※ 14 August 2021

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TUPAB223

Design of Double- and Multi-Bend Achromat Lattices with Large Dynamic Aperture and Approximate Invariants

1945

Y. Li, R.S. Rainer, V.V. Smaluk
BNL, Upton, New York, USA
K. Hwang, C.E. Mitchell, R.D. Ryne
LBNL, Berkeley, California, USA

Funding: Funded by U.S. Department of Energy (DOE) under Contract No. DE-SC0012704 (BNL) and DE-AC02-05CH11231 (LBNL), U.S. DOE Early Career Research Program under the Office of High Energy Physics.
A numerical method to design nonlinear double- and multi-bend achromat (DBA and MBA) lattices with approximate invariants of motion is described. The search for such nonlinear lattices is motivated by Fermilab’s Integrable Optics Test Accelerator (IOTA), whose design is based on an integrable Hamiltonian system with two invariants of motion. While it may not be possible to design an achromatic lattice for a dedicated synchrotron light source storage ring with one or more exact invariants of motion, it is possible to tune the sextupoles and octupoles in existing DBA and MBA lattices to produce approximate invariants. In our procedure, the lattice is tuned while minimizing the turn-by-turn fluctuations of the Courant-Snyder actions Jx and Jy at several distinct amplitudes, while simultaneously minimizing diffusion of the on-energy betatron tunes. The resulting lattices share some important features with integrable ones, such as a large dynamic aperture, trajectories confined to invariant tori, robustness to resonances and errors, and a large amplitude-dependent tune-spread.

Poster TUPAB223 [2.392 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB223

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paper received ※ 10 May 2021 paper accepted ※ 15 June 2021 issue date ※ 20 August 2021

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TUPAB224

Non-Linear Variation of the Beta-Beating Measured From Amplitude

1949

T. Pugnat, B. Dalena
CEA-IRFU, Gif-sur-Yvette, France
A. Franchi
ESRF, Grenoble, France
R. Tomás García
CERN, Geneva, Switzerland

Accelerator physics needs advanced modeling and simulation techniques, for beam stability studies but also for the measurement of beam parameters like the Twiss parameters. A deeper understanding of magnetic field non-linearities effects will greatly help in the improvement of future circular collider design, performance, and diagnostics. This paper studies the variation of the \beta-beating with the action of the particle generated by non-linear Resonance Driving Terms, both from a theoretical and an experimental point of view.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB224

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 21 August 2021

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TUPAB225

3D Magnetic Field Analysis of LHC Final Focus Quadrupoles with Beam Screen

1952

T. Pugnat, B. Dalena, C. Lorin
CEA-IRFU, Gif-sur-Yvette, France
S. Bagnis
CEA-DRF-IRFU, France

During the LHC commissioning, a discrepancy in the non-linear corrector strengths between the model and the beam-based values has been observed*. This has motivated the reconstruction of the 3D finite element model for the LHC final focusing MQXA type magnet. The longitudinal higher orders magnetic field pseudo-harmonics are computed taking into account ovalization of the magnet, interconnections design, and beam screens. The effect of this 3D field on the computation of the nonlinear correctors is evaluated and compared with beam-based corrector values.
*E. H. Maclean et al., "New approach to LHC optics commissioning for the nonlinear era", Phys. Rev. Acc. B, vol. 22, pp. 061004, June 2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB225

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paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 12 August 2021

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TUPAB226

Study of the Third-Order Parametric Resonance Induced by RF Modulation

1956

P.F. Liang, H.S. Xu
IHEP, Beijing, People’s Republic of China

There were both analytic and experimental studies on the effects of RF modulation on bunch lengthening in electron storage rings. Nevertheless, the increase of bunch energy spread will happen in the meantime. Therefore, the degradation of bunch quality may limit the potential applications of the RF modulation technique. As a consequence, we believe that the comprehensive studies of the parametric resonance induced by RF modulation are necessary for understanding the physics picture better and seeking new possibilities of applications of this technique. The studies on the beam dynamics closed to the 3v_s RF phase modulation would be presented here. Based on the basic longitudinal synchrotron equations of motion, we obtained analytically the longitudinal modulated Hamiltonian and various parameters in longitudinal phase space, such as the fixed points, island tune, island width. The validity of the analytic results was checked by simulations. Furthermore, the dependence of the bunch parameters, such as energy spread and bunch length, on the modulation settings is also discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB226

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 13 August 2021

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TUPAB227

Simultaneous Compensation of Phase and Amplitude Dependent Geometrical Resonances Using Octupoles

1960

F. Plassard, Y. Hidaka, Y. Li, T.V. Shaftan, V.V. Smaluk, G.M. Wang
BNL, Upton, New York, USA

As the new generation of light sources are pushing toward diffraction limited storage rings with ultra-low emittance beams, nonlinear beam dynamics become increasingly difficult to control. It is a common practice for modern designs to use a sextupole scheme that allows simultaneous correction of natural chromaticity and energy independent, or geometrical, sextupolar resonances. However, the remaining higher order terms arising from the cross talks of the sextupole families set a strong limitation on the achievable dynamic aperture. This paper presents a simulation-based recipe to use octupoles together with this sextupole scheme to provide simultaneous self-compensation of linear amplitude dependent tune shift together with phase-dependent octupolar and higher order geometrical resonant driving terms. The correction method was built based on observations made on a simple FODO model, then applied to a realistic low emittance lattice, designed in the framework of the upgrade of the National Synchrotron Light Source II (NSLS-II).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB227

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 14 August 2021

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TUPAB228

IOTA Run 2 Beam Dynamics Studies in Nonlinear Integrable Systems

1964

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev, A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the U.S. NSF under award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy.
Nonlinear integrable optics is a promising design approach for suppressing fast collective instabilities. To study it experimentally, a new storage ring, the Integrable Optics Test Accelerator (IOTA), was built at Fermilab. IOTA has recently completed its second scientific run, incorporating many hardware and instrumentation improvements. This report presents the results of the two integrable optics experiments - the quasi-integrable Henon-Heiles octupole system and the fully integrable Danilov-Nagaitsev system. We demonstrate tune spread and dynamic aperture in agreement with tracking simulations, and a stable crossing of the integer resonance. Based on recovered single-particle phase space dynamics, we show improved invariant jitter consistent with intended effective Hamiltonian. We conclude by outlining future plans and efforts towards proton studies and larger designs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB228

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paper received ※ 31 May 2021 paper accepted ※ 23 June 2021 issue date ※ 10 August 2021

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TUPAB231

Cooling of an Annular Beam by Using Nonlinear Effects

1968

F. Capoani, M. Giovannozzi, R. Tomás García
CERN, Geneva, Switzerland
A. Bazzani, F. Capoani
Bologna University, Bologna, Italy

In recent years, nonlinear effects have been used to modify the transverse beam distribution by crossing nonlinear resonances adiabatically. This allows generating transversally split beams, in which the initial single Gaussian is divided into several ones depending on the order and stability type of the resonance used. Nonlinear effects could be used to try and cool a beam by acting on its transverse beam distribution. In this paper, we present and discuss the special case of a beam with an annular distribution, showing how the resulting emittance could be reduced by means of nonlinear effects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB231

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paper received ※ 10 May 2021 paper accepted ※ 16 June 2021 issue date ※ 21 August 2021

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TUPAB232

Linear Coupling and Adiabaticity of Emittance Exchange

1972

F. Capoani, M. Giovannozzi
CERN, Geneva, Switzerland
A. Bazzani, F. Capoani
Bologna University, Bologna, Italy
A.I. Neishtadt
IKI, Moscow, Russia
A.I. Neishtadt
Loughborough University, Leicestershre, United Kingdom

In circular accelerators, crossing the coupling resonance induces the exchange of the transverse emittances, provided the process is adiabatic. In this paper, we introduce a theoretical framework to analyze the resonance-crossing process, based on Hamiltonian mechanics, which is capable of explaining all the features of the emittance exchange process.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB232

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paper received ※ 11 May 2021 paper accepted ※ 16 June 2021 issue date ※ 27 August 2021

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TUPAB233

Diffusive Models for Nonlinear Beam Dynamics

1976

C.E. Montanari, A. Bazzani
Bologna University, Bologna, Italy
M. Giovannozzi, C.E. Montanari
CERN, Geneva, Switzerland

Diffusive models for representing the nonlinear beam dynamics in a circular accelerator ring have been developed in recent years. The novelty of the work presented here with respect to older approaches is that the functional form of the diffusion coefficient is derived from the time stability estimate of the Nekhoroshev theorem. In this paper, we discuss the latest results obtained for simple models of nonlinear betratron motion.

Poster TUPAB233 [0.574 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB233

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paper received ※ 11 May 2021 paper accepted ※ 23 June 2021 issue date ※ 23 August 2021

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TUPAB234

Exploring Accelerators for Intense Beams with the IBEX Paul Trap

1980

J.A.D. Flowerdew
University of Oxford, Oxford, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 12 August 2021

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TUPAB235

Dynamic Aperture Optimization in the EIC Electron Storage Ring with Two Interaction Points

1984

D. Marx, Y. Li, C. Montag, S. Tepikian, F.J. Willeke
BNL, Upton, New York, USA
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
G.H. Hoffstaetter, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
In the Electron-Ion Collider (EIC), which is currently being designed for construction at Brookhaven National Laboratory, electrons from the electron storage ring will collide with hadrons, producing luminosities up to 10³⁴ cm^-2 s^-1. The baseline design includes only one interaction point (IP), and optics have been found with a suitable dynamic aperture in each dimension. However, the EIC project asks for the option of a second IP. The strong focusing required at the IPs creates a very large natural chromaticity (about -125 in the vertical plane for the ring). Compensating this linear chromaticity while simultaneously controlling the nonlinear chromaticity to high order to achieve a sufficient momentum acceptance of 1% (10 σ) at 18 GeV is a considerable challenge. A scheme to compensate higher-order chromatic effects from 2 IPs by setting the phase advance between them does not, by itself, provide the required momentum acceptance for the EIC Electron Storage Ring. A thorough design of the nonlinear optics is underway to increase the momentum acceptance using multiple sextupole families, and the latest results are presented here.

Poster TUPAB235 [3.426 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB235

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 20 August 2021

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TUPAB236

Progress on the Electron Gun Design for a McMillan Electron Lens in the Fermilab Integrable Optics Test Accelerator (IOTA)

1988

B.L. Cathey, G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
This paper covers the progress made so far in designing the first McMillan electron lens for the Fermilab IOTA ring. The novel design allows for an increase in tune spread without limiting the dynamic aperture due to its integrability. Shown are simulations for an electron gun design to generate the specific required current density distribution for the nonlinear integrable system in IOTA.

Poster TUPAB236 [5.391 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB236

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021

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TUPAB237

Symplectic Tracking Through Field Maps

1992

S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
B.T. Folsom, E. Lafacepresenter, R. Miyamoto
ESS, Lund, Sweden

For many applications, it is necessary to track particles using field maps, instead of an analytic representation of the fields which is typically not available. These field maps come about while designing elements such as realistic magnets or radiofrequency cavities, and represent the field geometry on a mesh in space. However, simple interpolation of the fields from the field maps does not guarantee that the resulting tracking scheme satisfies the symplectic condition. Here we present a general method to decompose the field-map potential in the sum of interpolating functions that produces, by construction, a symplectic integrator.

Poster TUPAB237 [0.307 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB237

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 22 August 2021

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TUPAB238

Algorithm to Analyze Complex Magnetic Structures Using a Tube Approach

1995

B. Riemann, M. Aiba
PSI, Villigen PSI, Switzerland

Modern synchrotron light sources often require sophisticated multipole field distributions that need to be realized by complex magnet structures. To pre-validate these magnet structures via simulations, the extraction procedure needs to output standard multipoles as well as fringe effects. The approach presented in this manuscript uses a volumetric grid map of the magnetic flux density as input. After computation of the reference trajectory (leapfrog integration), a large linear system is solved to compute transverse polynomial coefficients of the magnetic scalar potential in a series of interconnected thin cylinders (linear basis functions) along with that reference. The import of these coefficients into a lattice simulation is discussed using a modification of the tracking code Tracy. The shown approach is routinely used to check models of SLS 2.0 magnets for their properties.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB238

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021

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TUPAB239

Radiation of a Charged Particle Bunch Moving Along a Deep Corrugated Surface with a Small Period

1999

E.S. Simakov, A.V. Tyukhtin
Saint Petersburg State University, Saint Petersburg, Russia

Funding: This work was supported by the Russian Science Foundation (Grant No. 18-72-10137).
We investigate the electromagnetic radiation of a bunch moving along a corrugated conductive surface. It is assumed that wavelengths under consideration are much more than the period of the corrugation. In this case, the corrugated structure can be replaced with a smooth surface on which so-called equivalent boundary conditions (EBC) are fulfilled*. In fact, we deal with anisotropic surface characterized by certain matrix impedance. Here, we consider the case of deep corrugation, i.e. we assume that the depth of the structure is much more than its period (the case of shallow corrugation was studied earlier**). Using the EBC we obtain electromagnetic field components which are presented in form of spectral integrals. It is shown that the bunch generates surface waves propagating in the plane of the structure, whereas volume radiation is absent at the frequencies under consideration. We also consider the energy losses of the bunch. Typical dependences of a spectral density of the energy losses on corrugation parameters are obtained and analyzed. It is demonstrated that the features of the surface waves can be used for the bunch diagnostics.
* E.I. Nefedov, A.N. Sivov. Electrodynamics of periodic structures. Moscow, Nauka, 1977, 208 p. (in Russian).
** E.S. Simakov, A.V. Tyukhtin, S.N. Galyamin, Phys. Rev. AB, 22, 061301 (2019).

Poster TUPAB239 [0.637 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB239

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 23 August 2021

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TUPAB240

The Impact of Trajectory-Shaped Coil on the Beam Dynamics in the SC230 Superconducting Cyclotron

2002

I.D. Lyapin, O. Karamyshev, V. Malinin, D. Popov
JINR/DLNP, Dubna, Moscow region, Russia
G.A. Karamysheva
JINR, Dubna, Moscow Region, Russia

In this paper, we compared the effect of the cyclotron coil shape on the beam dynamics. Two models were created. The first has a conventional round coil, the second has a coil that follows the trajectory of the protons. Parameters of extracted beams are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB240

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021

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TUPAB241

Characterization of the RF-Cavities geometry in Order to Optimize the Beam Parameters in S-Band On-Axis LINACs

2005

A. Khosravi, B. Shokri
LAPRI, Tehran, Iran
N. Khosravi
ILSF, Tehran, Iran

The RF characteristics of an accelerating tube are primarily assigned to geometrical features of a cavity. As a consequence of this geometry, the final electric field will make the shape of our Gaussian bunch and the final dose. The accelerating field can be studied considering the nose cone, gap, and bore radius. In dual electron linacs, the role of input power and bunch current is inevitable. Therefore, the geometrical issues of RF-cavities are studied in a 6MeV electron on-axis SW tube. To make an accurate comparison, each RF-cavity is designed and optimized by POISSON SU-PERFISH. The optimized cavities are imported to the PIC solver of CST. Then the beam characteristics are studied on a predefined target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB241

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paper received ※ 18 May 2021 paper accepted ※ 14 June 2021 issue date ※ 30 August 2021

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TUPAB242

The Beam-Study of the Side and On-Axis RF Cavities in S-Band 6 MeV LINACs

2008

A. Khosravi, B. Shokri
LAPRI, Tehran, Iran
N. Khosravi
ILSF, Tehran, Iran

The geometry of side and on-axis RF cavities are two magnetic-coupled designs for the different LINAC applications. The electromagnetic fields, RF power, beam parameters, thermal stability, and manufacturing costs are the most critical factors in cavity type selection in each application. In this article, both RF-cavities are optimized in POISSON SUPERFISH code to compare the beam parameters accurately. Then the optimized cavities are making a tube and compare in ASTRA 1D code and CST 3D software. At last, the thermal sensitivity of both models is studied in MPHYSICS module of the CST. As a result, the final decision can be achieved on the side or on-axis cavities considering the input power, costs, beam properties, and thermal stability for the different applications of the LINACs

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB242

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB243

Investigation of the Buncher Effect on Beam Properties in SW 3-6 MeV LINACs

2012

A. Khosravi, B. Shokri
LAPRI, Tehran, Iran
N. Khosravi
ILSF, Tehran, Iran

The best quality of an electron beam is the primary goal of a linear accelerator design. Beam-study on a buncher section can lead us to a better perspective of the modulation and acceleration of a beam to optimize the final Gaussian beam. Five setups of different bunchers are designed, optimized, and presented in this article. A more brilliant and converged beam with a higher current, transverse emittance and smaller beam size is the study’s goal.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB243

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paper received ※ 18 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021

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TUPAB244

THE WAKEFIELD STUDY OF THE RF-SHIELDED BELLOWS AT THE ILSF STORAGE RING

2015

N. Khosravi, E. Ahmadi, M. Akhyani
ILSF, Tehran, Iran
M. Akhyani
EPFL, Lausanne, Switzerland
A. Khosravipresenter
LAPRI, Tehran, Iran

The corrugated geometry of the bellows made it critical to be shielded with an RF-Shield. Different types of RF shields can be applied to the ILSF vacuum chamber to cover this component’s destructive impedance peaks. Then, the Impedance study and optimization of the RF shields can improve the impedance budget. In this article, two common types of RF shields are simulated in CST software.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB244

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paper received ※ 16 May 2021 paper accepted ※ 02 June 2021 issue date ※ 14 August 2021

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TUPAB245

WAKEFIELD AND HEAT LOAD STUDY OF THE GATE VALVES AT ILSF STORAGE RING

2018

N. Khosravi, E. Ahmadi, M. Akhyani
ILSF, Tehran, Iran
M. Akhyani
EPFL, Lausanne, Switzerland
S. Dastan
IPM, Tehran, Iran
A. Khosravipresenter
LAPRI, Tehran, Iran

As one part of the ILSF storage ring, the rf-shield of the gate valves generates considerable interest in terms of wake impedance and heat-load. Inside the gate valves, there is a vacuity, which causes low frequencies resonances, and it can lead to beam instabilities. Therefore, controlling and eliminating these frequencies will be substantial. A radio frequency rf-shield structure, which conceals this transverse gap of the gate valves, is indispensable for low emittance chambers. This paper analyzes the wake impedance and thermal behavior of a finger-band RF shield in the gate valve.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB245

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 13 August 2021

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TUPAB246

Numerical Simulation and Beam-Dynamics Study of a Hollow-Core Woodpile Coupler for Dielectric Laser Accelerators

2022

G.S. Mauro, D. Mascali, G. Sorbello, G. Torrisi
INFN/LNS, Catania, Italy
A. Bacci
INFN/LASA, Segrate (MI), Italy
C. De Angelis, A. Locatelli
University of Brescia, Brescia, Italy
A.R. Rossi
INFN-Milano, Milano, Italy
G. Sorbello
University of Catania, Catania, Italy

Hollow core dielectric microstructures powered by lasers represent a new and promising area of accelerator research thanks to the higher damage threshold and accelerating gradients with respect to metals at optical wavelengths. In this paper we present the design of a dielectric Electromagnetic Band Gap (EBG) mode converter for high-power coupling of the accelerating mode in Dielectric Laser Accelerators (DLAs). The design is wavelength-independent, and here we propose an implementation operating at 90.505 GHz (wavelength 3.3 mm) based on a silicon woodpile structure. The coupler is composed by two perpendicularly coupled hollow-core waveguides: a TE-like mode waveguide (excited from RF/laser power) and a TM-like mode accelerating waveguide. The structure has been numerically designed and optimized, presenting Insertion Losses (IL) < 0.3 dB and an efficient mode conversion in the operating bandwidth. The properties and effectiveness of the confined accelerating mode have been optimized in order to derive the needed accelerating gradient. The simulated electric field has been used as input for Astra beam-dynamics simulations in order to compute the beam properties.

Poster TUPAB246 [2.209 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB246

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paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 13 August 2021

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TUPAB247

Influence of the Profile of the Dielectric Structure on the Electric Fields Excited by a Laser in Dielectric Accelerators Based on Chip

2026

A. Vasyliev, O.O. Bolshovpresenter, K. Galaydych, A.I. Povrozin, G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine

Funding: The National Research Foundation of Ukraine, program "Leading and Young Scientists Research Support" (project # 2020.02/0299).
To provide experimental researches at the NSC KIPT theoretical studies and computations of the electron acceleration in a dielectric laser accelerator have been carried out. Laser accelerator consists of two periodic quartz structures on diffraction gratings or Chips, symmetrically located along both sides of the vacuum accelerating channel. Using PIC numerical simulations, electromagnetic fields excited by laser radiation with a wavelength of 800 nm in dielectric laser accelerators were investigated. The influence of the shape and depth of the profile of diffraction gratings or Chip structures on the distribution of the electric field in the interaction space has been studied. For modeling, different types of profiles were taken, both in serial and a unique structure. In consequence of the analysis of the obtained results, estimated efficiency of acceleration was defined for each type of profile. The rectangular profile of the diffraction grating with the maximum accelerating gradient was selected as optimal for the next experiments.

Poster TUPAB247 [1.195 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB247

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 11 August 2021

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TUPAB248

A Parallel Time Domain Thermal Solver for Transient Analysis of Accelerator Cavities

2030

C.-K. Ng, L. Ge, Z. Li, L. Xiao
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE under contract AC02-76SF00515.
Simulation of thermal effects in accelerator cavity is normally performed assuming steady state solution where a static thermal solver suffices to evaluate temperature gradients and impacts on mechanical design. However, during the rf pulse ramp up or the machine system cool-down process, when the field in the cavity changes rapidly, transient effects need to be taken into account. A parallel time domain thermal solver has been developed in the finite element multi-physics code suite ACE3P with integrated electromagnetic, thermal and mechanical modeling capabilities. The implementation takes advantage of the parallel computation infrastructure of ACE3P and shares most of the ingredients in mesh generation, matrix assembly, time advancement scheme and postprocessing. In this paper, we will outline the finite element formulation of the transient thermal problem and verify the implementation against analytical solutions and existing numerical results. The thermal solver has also been coupled to ACE3P mechanical solver, allowing stress and strain analysis during the transient stage. Application of the transient thermal solver to realistic accelerator cavities will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB248

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paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 02 September 2021

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TUPAB249

Diffraction at the Open-Ended Dielectric-Loaded Circular Waveguide

2033

S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia

Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
Contemporary beam and THz technologies are tightly interlaced during last years. Strong THz fields allow realization of THz driven electron guns, THz bunch compression, streaking* and THz driven wakefield acceleration**. Inversely, dielectric capillaries similar to those used for THz bunch manipulation can be in turn utilized for development of high-power narrow-band THz sources***. Mentioned cases involve interaction of THz waves and particle bunches with an open end of certain dielectric loaded waveguide structure, most frequently a circular capillary. For further development of the discussed prospective topics a rigorous approach allowing analytical investigation of both radiation from open-ended capillaries and their excitation by external source would be extremely useful. We present an elegant and efficient rigorous method for solving circular open-ended dielectric-loaded waveguide diffraction problems based on Wiener-Hopf technique. We deal with the case of uniform dielectric loading and internal excitation by a waveguide mode. S-parameters, near-field and far-field distributions are presented. The obtained results can be also applied to the narrow band wakefield.
* L. Zhao et al., Phys. Rev. Lett., 124, 054802 (2020).
** M.T. Hibberd et al., Nat. Photonics, 14, 755-759 (2020).
*** D. Wang et al., Rev. Sci. Instr., 89(9), 093301 (2018).

Poster TUPAB249 [2.160 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB249

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 21 August 2021

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TUPAB250

Axicon-Based Concentrator for Cherenkov Radiation

2036

S.N. Galyamin, A.V. Tyukhtin
Saint Petersburg State University, Saint Petersburg, Russia

Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
We propose a new type of axisymmetric dielectric target - an "axicon-based concentrator" - which effectively concentrates generated Cherenkov radiation (CR) into a small vicinity of a focus point. It consists of two "glued" bodies of revolution: a hollow axicon and a hollow "lens." A theoretical investigation of the radiation field produced by a charge moving through the discussed radiator is performed for the general case where a charge trajectory is shifted with respect to the structure axis. The idea of a dielectric target with a specific profile of the outer surface and suitable analytical methods were presented and developed in our preceding papers *, **. An essential advantage of the current version of the device is that it allows the efficient concentration of CR energy from relativistic particles, making this device extremely prospective for various applications such as beam-driven THz sources and bunch diagnostic systems.
* S.N. Galyamin et al., Phys. Rev. Accel. Beams 22, 083001 (2019); 22, 109901 (2019).
** A.V. Tyukhtin et al., Phys. Rev. A 102, 053514 (2020).

Poster TUPAB250 [1.255 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB250

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paper received ※ 24 May 2021 paper accepted ※ 21 June 2021 issue date ※ 12 August 2021

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TUPAB251

Impedance Studies of a Corrugated Pipe for KARA

2039

S. Maier, M. Brosi, A. Mochihashi, A.-S. Müller, M.J. Nasse, M. Schwarz
KIT, Karlsruhe, Germany

Funding: DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
At the KIT storage ring KARA (KArlsruhe Research Accelerator) it is planned to install an impedance manipulation structure in a versatile chamber to study and eventually control the influence of an additional impedance on the beam dynamics and the emitted coherent synchrotron radiation. For this purpose the impedance of a corrugated pipe is under investigation. In this contribution, we present first results of simulations showing the impact of different structure parameters on its impedance and wake potential.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB251

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021

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TUPAB252

Minimization of NICA Collider Impedance

2043

S.A. Melnikov, I.N. Meshkov
JINR, Dubna, Moscow Region, Russia
K.G. Osipov
JINR/VBLHEP, Dubna, Moscow region, Russia

The paper presents the results of the longitudinal impedance minimization for the beam tube section in the arches of the NICA collider ring, consisting of a pumping pipe, a BPM station, and a bellows assembly, and considers the contribution of the impedance of this section to the ion beam stability in the NICA collider ring. To confirm the efficiency of the optimized design, a BPM prototype was fabricated, and a test bench was built for further laboratory measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB252

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paper received ※ 13 May 2021 paper accepted ※ 14 June 2021 issue date ※ 10 August 2021

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TUPAB254

Limiting Coherent Longitudinal Beam Oscillations in the EIC Electron Storage Ring

2046

B. Podobedov
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
M. Blaskiewicz
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We study coherent longitudinal beam oscillations in the EIC electron storage ring (ESR). We show that to avoid unacceptable hadron emittance growth due to finite crossing angle, the amplitude of these oscillations needs to be limited to a fraction of a millimeter. Using an analytical model we estimate the amplitude of these oscillations under the two scenarios: 1) the beam is passively stable and the oscillations are driven by RF phase noise only; 2) a coupled-bunch instability, presently expected in the ESR, is damped by a longitudinal feedback system. We show that, for the 2nd scenario, comfortable specifications for RF phase noise and feedback sensor noise will be sufficient to maintain the oscillation amplitude within the required limits.

Poster TUPAB254 [1.347 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB254

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paper received ※ 12 May 2021 paper accepted ※ 18 June 2021 issue date ※ 26 August 2021

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TUPAB255

Longitudinal Beam Dynamics and Coherent Synchrotron Radiation at cSTART

2050

M. Schwarz, E. Bründermann, D. El Khechen, B. Härer, A. Malygin, A.-S. Müller, M.J. Nasse, A.I. Papash, R. Ruprecht, J. Schäfer, M. Schuh, P. Wesolowski
KIT, Karlsruhe, Germany

The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of LWFA-like beams in a very large momentum acceptance storage ring. The project will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a source of ultra-short bunches, will serve as an injector for cSTART to benchmark and emulate laser-wakefield accelerator-like beams. In a second stage a laser-plasma accelerator will be used as an injector, which is being developed as part of the ATHENA project in collaboration with DESY and Helmholtz Institute Jena (HIJ). With an energy of 50 MeV and damping times of several seconds, the electron beam does not reach equilibrium emittance. Furthermore, the critical frequency of synchrotron radiation is 53 THz and in the same order as the bunch spectrum, which implies that the entire bunch radiates coherently. We perform longitudinal particle tracking simulations to investigate the evolution of the bunch length and spectrum as well as the emitted coherent synchrotron radiation. Finally, different options for the RF system are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB255

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paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021

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TUPAB256

Investigation of Damping Effects of the Crab Cavity Noise Induced Emittance Growth

2054

N. Triantafyllou, L.R. Carver, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou, N. Triantafyllou
CERN, Meyrin, Switzerland
L.R. Carver
ESRF, Grenoble, France
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

Crab cavities will be installed at the two main interaction points (IP1 and IP5) of the High Luminosity LHC (HL-LHC) in order to minimize the geometric reduction of the luminosity due to the crossing angle. Two prototype crab cavities have been installed into the SPS machine and were tested with a proton beam in 2018, to study the expected emittance growth induced by RF noise. The measured emittance growth was found to be a factor 2-3 lower than predicted from the available analytical and computational models. Damping mechanisms from the transverse impedance, which is not included in the available theories, are studied as a possible explanation for the observed discrepancy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB256

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paper received ※ 18 May 2021 paper accepted ※ 18 June 2021 issue date ※ 23 August 2021

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TUPAB257

Analysis of Multibunch Spectrum for an Uneven Bunch Distribution in a Storage Ring

2058

R. Li, F. Marhauser
JLab, Newport News, Virginia, USA

Funding: This work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Modern storage-ring designs often require an uneven bunch distribution pattern. An uneven bunch fill pattern can result in complex structures for the beam current spectra. Particularly at high average beam currents, these complex current spectra need to be taken into account in concern of beam-dynamical effects. In this study, we analyze a beam current spectrum for various filling patterns with bunch trains and gaps. The characteristics of the resulting beam current spectra are illustrated and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB257

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paper received ※ 21 June 2021 paper accepted ※ 28 June 2021 issue date ※ 12 August 2021

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TUPAB258

Impact of Coherent Beam-Beam Interaction on the Landau Damping of the Transverse Coupled-Bunch Instability

2062

R. Li
JLab, Newport News, Virginia, USA
M. Blaskiewicz
BNL, Upton, New York, USA

Funding: This work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
In the EIC design, at high average-current operation, the transverse coupled-bunch instability (TCBI) induced by the long-range transverse resistive-wall wakefield in the electron storage ring (eSR) has a fast growth rate and requires efficient mitigation. A natural mitigation mechanism is provided by the beam-beam interaction at the interaction point (IP), which gives a strong Landau damping for the TCBI in the eSR. In this study, using a simplified simulation model, we investigate how this Landau damping from the beam-beam interaction behaves when the coherent beam-beam interaction at IP is considered. Our method and results will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB258

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paper received ※ 21 June 2021 paper accepted ※ 01 July 2021 issue date ※ 25 August 2021

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TUPAB260

A Beam Screen to Prepare the RHIC Vacuum Chamber for EIC Hadron Beams: Conceptual Design and Requirements

2066

S. Verdú-Andrés, M. Blaskiewicz, J.M. Brennan, X. Gu, R.C. Gupta, A. Hershcovitch, M. Mapes, G.T. McIntyre, J.F. Muratore, S.K. Nayak, S. Peggs, V. Ptitsyn, R. Than, J.E. Tuozzolo, D. Weiss
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Electon Ion Collider (EIC) hadron ring will use the existing Relativistic Heavy Ion Collider storage rings, including the superconducting magnet arcs. The vacuum chambers in the superconducting magnets and the cold mass interconnects were not designed for EIC beams and so must be updated to reduce its resistive-wall heating and to suppress electron clouds. To do so without compromising the EIC luminosity goal, a stainless steel beam screen with co-laminated copper and a thin layer of amorphous carbon will be installed. This paper describes the main requirements that our solution for the hadron ring vacuum chamber needs to satisfy, including impedance, aperture limitations, vacuum, thermal and structural stability, mechanical design, installation and operation. The conceptual design of the beam screen currently under development is introduced.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB260

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paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 12 August 2021

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TUPAB261

The Ferrite Loaded Cavity Impedance Simulation

2070

L. Huang, X. Li, S. Wang, S.Y. Xupresenter
IHEP, Beijing, People’s Republic of China
B. Wu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: Work supported by NNSF of China: N0. U1832210
The Rapid Cycling Synchrotron of the China Spallation Neutron Source is a high-intensity proton accelerator, it accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV in 20 ms. The transverse coupling bunch instability is observed in beam commissioning. The source has been investigating from the commissioning. The RF acceleration system consists of eight ferrite-loaded cavities. The impedance is simulated and there is a narrow-band impedance of the ferrite cavity at about 17 MHz

Poster TUPAB261 [1.145 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB261

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paper received ※ 13 May 2021 paper accepted ※ 31 May 2021 issue date ※ 21 August 2021

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TUPAB262

The Characteristic of the Beam Position Growth in CSNS/RCS

2073

L. Huang, S. Wang
IHEP, Beijing, People’s Republic of China
S.Y. Xupresenter
DNSC, Dongguan, People’s Republic of China

Funding: Work supported by NNSF of China: N0. U1832210
An instability of the beam position growth is observed in the beam commissioning of the Rapid Cycling Synchrotron of the China Spallation Neutron Source. To simplify the study, a series of measurements have been performed to characterize the instability in the DC mode with consistent energy of 80 MeV. The measurement campaign is introduced in the paper and it conforms to the characteristics of the coupled bunch instability.

Poster TUPAB262 [3.748 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB262

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paper received ※ 13 May 2021 paper accepted ※ 02 June 2021 issue date ※ 22 August 2021

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TUPAB263

The Phase Loop Status of the RF System in CSNS/RCS

2076

L. Huang, X. Li, S. Wang
IHEP, Beijing, People’s Republic of China
M.T. Li, H.Y. Liupresenter
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Liu
DNSC, Dongguan, People’s Republic of China

The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator. The acceleration system consists of eight ferrite loaded cavities. The RCS is the space charge dominant machine and it is mitigated through the bunch factor optimization in the beam commissioning, so the injected beam will occupy a larger bucket size and unavoidable mismatch with the bucket, thus the dipole oscillation is excited. The phase loop scheme is designed to restrict the oscillation in the RF system, but the transmission efficiency is reduced by the phase loop and the bunch factor also increases, so the phase loop scheme is studied. To keep the phase loop but also maintain the transmission efficiency, we optimized the original phase loop scheme, but the beam loss still increases small when the loop on.

Poster TUPAB263 [1.548 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB263

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paper received ※ 13 May 2021 paper accepted ※ 02 June 2021 issue date ※ 21 August 2021

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TUPAB264

Shielding of CSR Wake in a Drift

2079

G. Stupakov
SLAC, Menlo Park, California, USA

Funding: Work supported by the Department of Energy, contract DE-AC03-76SF00515.
A one-dimensional model of coherent synchrotron radiation (CSR) wakefield developed in Refs. [*,**] is used in computer codes for the simulation of relativistic electron beams. It includes transient effects at the entrance and exit from a bending magnet of finite length. In the ultra-relativistic limit, v=c, the exit CSR wake decays inversely proportional to the distance from the magnet end. To calculate the total energy loss of the beam one needs to integrate this wake to infinity, but the integral diverges. This means that one has to either drop the assumption of the infinite value of the Lorentz factor or take into account the shielding effect of the metal walls in the vacuum chamber. In practice, the latter effect is often dominant. In this work, we derive formulas for the CSR wake in the drift after an exit from the magnet that incorporates the shielding by two parallel metal plates. They allow computing the energy loss of different particles in the beam.
* E. L. Saldin, E. A. Schneidmiller, and M. V. Yurkov. NIMA v. 398, p. 373 (1997).
** G. Stupakov and P. Emma. In: Proceedings of 8th EPAC. Paris, France, 2002, p. 1479.

Poster TUPAB264 [0.661 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB264

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paper received ※ 10 May 2021 paper accepted ※ 25 June 2021 issue date ※ 22 August 2021

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TUPAB265

Bunch Lengthening of the HALF Storage Ring in the Presence of Passive Harmonic Cavities

2082

T.L. He, Z.H. Bai, G.Y. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

A passive 3^rd harmonic RF system, being necessary for the Hefei Advanced Light Facility (HALF) storage ring under design, will be employed to lengthen the bunches for suppressing the intrabeam scattering and improving the beam lifetime. However, the transient beam loading due to the fundamental mode may significantly reduce the bunch lengthening. Since the scale of transient effects is proportional to R/Q, the effects of R/Q on bunch lengthening, in uniform fill pattern with the near-optimum condition fulfilled, are analyzed by multibunches multiparticles tracking simulation. It indicates that the passive superconducting harmonic cavity with a lower R/Q is preferred by HALF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB265

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paper received ※ 16 May 2021 paper accepted ※ 18 June 2021 issue date ※ 20 August 2021

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TUPAB266

Periodic Transient Beam Loading Effects Predicted by a Semi-Analytical Method

2086

T.L. He, Z.H. Bai, G. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In this paper, we improve a semi-analytical method, which can be not only used for bunch lengthening under equilibrium conditions, but also applied to the prediction of a periodic transient beam loading effect. This periodic transient is induced by the presence of the passive harmonic cavity and might be encountered under specific conditions for a ultra-low emittance storage ring with a higher beam current.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB266

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paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021

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TUPAB267

Investigation of Beam Impedance and Heat Load in a High Temperature Superconducting Undulator

2089

D. Astapovych, H. De Gersem, E. Gjonaj
TEMF, TU Darmstadt, Darmstadt, Germany
T.A. Arndt, E. Bründermann, N. Glamann, A.W. Grau, B. Krasch, A.-S. Müller, R. Nast, D. Saez de Jauregui, A. Will
KIT, Eggenstein-Leopoldshafen, Germany

The use of high temperature superconducting (HTS) materials can enhance the performance of superconducting undulators (SCU), which can later be implemented in free electron laser facilities, synchrotron storage rings and light sources. In particular, the short period < 10 mm undulators with narrow magnetic gap < 4 mm are relevant. One of the promising approaches considers a 10 cm meander-structured HTS tapes stacked one above the other. Then, the HTS tape is wound on the SCU. The idea of this jointless undulator has been proposed by, and is being further developed at KIT. Since minimizing the different sources of heat load is a critical issue for all SCUs, a detailed analysis of the impedance and heat load is required to meet the cryogenic system design. The dominant heat source is anticipated to be the resistive surface loss, which is one of the subjects of this study. Considering the complexity of the HTS tape, the impedance model includes the geometrical structure of the HTS tapes as well as the anomalous skin effect. The results of the numerical investigation performed by the help of the CST PS solver will be presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB267

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paper received ※ 18 May 2021 paper accepted ※ 26 July 2021 issue date ※ 12 August 2021

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TUPAB269

Transverse Impedance of Lossy Circular Metal-Dielectric Waveguides

2093

M. Ivanyan, L.V. Aslyan
CANDLE SRI, Yerevan, Armenia
K. Flöttmann, F. Lemery
DESY, Hamburg, Germany

The properties of the transverse impedance of a dielectric-loaded metallic circular waveguide are investigated taking into account losses in the outer metallic pipe and in the inner dielectric layer. The dispersion relations, impedances, and wake functions for dipole modes are analyzed and compared for thin and thick dielectric layer cases. The correspondence of the resonant frequencies of the longitudinal monopole and transverse dipole impedances is established.

Poster TUPAB269 [0.906 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB269

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paper received ※ 16 May 2021 paper accepted ※ 28 May 2021 issue date ※ 10 August 2021

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TUPAB270

Thermal Transition Design and Beam Heat-load Estimation for the COLDDIAG Refurbishment

2097

H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The COLDDIAG (cold vacuum chamber for beam heat load diagnostics) developed at Karlsruhe Institute of Technology has been modified for more studies at cryogenic temperatures different from the previous operations at 4 K in a cold bore and at 50 K in a thermal shield. The key components in this campaign are two thermal transitions connecting both ends of the bore at 50 K with the shield at the same or higher temperature. In this paper, we present design efforts for the compact transitions, allowed heat intakes to the cooling power margin and mechanical robustness in the cryogenic environment. A manufacture scheme for the transition and its peripheral is also given. In addition, the beam heat loads in the refurbished COLDDIAG are estimated in terms of the accelerator beam parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB270

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paper received ※ 12 May 2021 paper accepted ※ 02 June 2021 issue date ※ 12 August 2021

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TUPAB272

Observation of Long-Range Wakefield Effects Generated in an Off-Resonance Tesla-Type Cavity

2101

A.H. Lumpkin, D.R. Edstrom, A. Lunin, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora
SLAC, Menlo Park, California, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The interest in controlling emittance dilution effects due to off-axis beam transport in accelerator cavities and the resulting dipolar modes is especially important for the facilities with lower emittance beams. The Fermilab Accelerator Science and Technology (FAST) facility has a unique configuration of two single cavities after the photocathode rf gun followed by a cryomodule. The second capture cavity (CC2) was run 15 kHz off resonance and without rf power while a 25-MeV beam was injected into it. The beam centroid effects were tracked by 10 rf button BPMs with bunch-by-bunch position readout capability downstream in a 12-m drift. Possible LRW effects seemed to dominate our previously observed near-resonant HOM effects at mode 14 in this cavity. This mode also shifted in frequency compared to that of the tuned case based on direct measurements. Submacropulse vertical position slewing of 1400 microns at 11 m downstream was observed with a 125 pC/bunch, 50 bunches per macropulse, and 25-MeV beam. The y-position slew amplitudes as a function of z were also measured. Horizontal positions also showed a slew effect. Both are emittance-dilution effects which one wants to mitigate.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB272

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 20 August 2021

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TUPAB273

Observations on Submicropulse Electron-Beam Effects From Short-Range Wakefields in Tesla-Type Superconducting Rf Cavities

2105

A.H. Lumpkin, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, A.L. Edelen, B.T. Jacobson, F. Zhou
SLAC, Menlo Park, California, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
In previous experiments at the Fermilab Accelerator Science and Technology (FAST) facility, the effects of higher-order modes (HOMs) in TESLA-type cavities on submacropulse centroid motion were elucidated*. We now have extended our investigations to short-range wakefields (SRWs) in these cavities. The latter result in submicropulse effects where the transverse wakefields cause head-tail centroid shifts. We used a Hamamatsu C5680 UV-visible synchroscan streak camera to synchronously sum the OTR from each of the 50 micropulses in the macropulse. We generated the y-t effect in the 41-MeV beam by purposely steering the beam off axis in y at the entrance of the first capture cavity. The head-tail transverse kicks within the 11-ps-long micropulses of 500 pC each were observed at the 100-micron level for steering off-axis in one cavity and several 100 microns for two cavities. These SRW results will be compared to simulations from the ASTRA model of a single micropulse in FAST. Since the SRW kicks go inversely with energy, these emittance-dilution effects are particularly relevant to the LCLS-II injector commissioning plans where <1 MeV beam will be injected into a TESLA-type cryomodule.
* A.H. Lumpkin et al, Phys. Rev. Accel. and Beams 23, 054401 (2020).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB273

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 28 August 2021

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TUPAB274

Investigations of Long-Range Wakefield Effects in a TESLA-type Cryomodule at FAST

2109

A.H. Lumpkin, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou
SLAC, Menlo Park, California, USA

Funding: *Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The preservation of low emittance of electron beams during transport in the accelerating structures of large facilities is an ongoing challenge. In the cases of the TESLA-type superconducting rf cavities currently used in the European X-ray Free-electron Laser (XFEL) and the under-construction Linac Coherent Light Source upgrade (LCLS-II), off-axis beam transport may result in emittance dilution due to transverse long-range wakefields (LRWs) and short-range wakefields (SRW)***. To investigate such effects, experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility with its unique configuration of two TESLA-type cavities after the photocathode rf gun followed by an 8-cavity cryomodule CM). We generated beam trajectory changes with the H/V125 corrector set located 4 m upstream of the cryomodule. At 125 pC/bunch, 50 bunches, 25-MeV input, and 100-MeV exit energy, we observed for the first time submacropulse position slews of up to 500 microns at locations ~3 m after the CM and a centroid oscillation at a difference frequency of 240 kHz further downstream. Both are emittance-dilution effects which we mitigated with selective upstream beam steering.
***W.K.H. Panofsky and M. Bander, Rev. Sci. Instr. 39, 206 (1968).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB274

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021

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TUPAB275

Enhanced Orthogonal Polarization Component Treatment in COTRI Model for Microbunched Beam Diagnostics

2113

D.W. Rule
Private Address, Silver Spring, USA
A.H. Lumpkinpresenter
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
We present the results of modifying our coherent optical transition radiation interferometry (COTRI) model’s treatment of the perpendicular polarization of OTR, Iperp. Our previous analytic approximation for Iperp was for beam divergences, sy << 1/g, where g is the Lorentz factor and sy is the rms y-component of the beam divergence. We have replaced our analytical form with a Gaussian quadrature for the convolution of Iperp with the divergence in theta-y. This extends the range of divergences we reliably model to sy > 1/g. Ipar, the parallel polarization in the model, is unchanged. Iperp is polarized along the y-axis and is proportional to the square of the y-component of the beam’s velocity distribution. We illustrate our results with two cases: 1) beam energy E=1 GeV, OTR wavelength 633 nm, Q=235 pC, microbunching fraction, bf=1%, divergences of 0.1-0.7 mrad, and rms beam sizes 2,10, and 30 microns; 2) E=375 MeV, wavelength 266 nm, Q=300 pC, bf=10%, divergences of 0.1-0,7 mrad, and rms beam sizes of 10,25,50, and 100 microns. We will present two cases that would be of interest for the diagnostics of laser-plasma accelerator beams* and pre-bunched FELs**, respectively.
* A. H. Lumpkin et al., Phys. Rev. Lett. 125, 014801 (2020).
** A. H. Lumpkin and D. W. Rule, in Proc., 39th International FEL Conference, FEL 2019 (JACoW Pub., Hamburg, Germany, 2019), pp. 408-411.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB275

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paper received ※ 22 May 2021 paper accepted ※ 10 June 2021 issue date ※ 20 August 2021

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TUPAB277

Bunch Length Characterizations for the Solaris Injector LINAC

2117

A. Curcio, M.A. Knafel, G.W. Kowalski, R. Panaś, M. Waniczek, A.I. Wawrzyniak
NSRC SOLARIS, Kraków, Poland

During 2020 the first characterization of bunch length and bunch profile in the Solaris injector LINAC has been performed since the start of its operation. In absence of more sophisticated bunch length diagnostics, we have adopted an inversion algorithm applied to beam energy spectra. In practice, the method applies a transformation matrix which maps the particle energy into the particle longitudinal coordinate along the bunch. The construction of this matrix is made analytically, based on the solution of the Liouville equation for the study of the longitudinal beam dynamics. The analytic approach has been benchmarked with experimental measurements of the beam properties along the machine and cross-checked with other tools, as particle tracking and/or beam optics codes. The final results are presented. Moreover, a new diagnostic station at the end of the LINAC has been installed which will host experiments of coherent radiation emission that will be used to confirm the validity of our observations. Preliminary simulations of the coherent spectra are finally reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB277

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 12 August 2021

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TUPAB278

The HL-LHC Beam Gas Vertex Monitor - Simulations for Design Optimisation and Performance Study

2120

H. Guerin, O.R. Jones, R. Kieffer, B. Kolbingerpresenter, T. Lefèvre, B. Salvant, J.W. Storey, R. Veness, C. Zamantzas
CERN, Meyrin, Switzerland
S.M. Gibson, H. Guerin
Royal Holloway, University of London, Surrey, United Kingdom

The Beam Gas Vertex (BGV) instrument is a non-invasive transverse beam profile monitor being designed as part of the High Luminosity Upgrade of the LHC (HL-LHC) at CERN. Its aim is to continuously measure bunch-by-bunch beam profiles, independent of beam intensity, throughout the LHC cycle. The primary components of the BGV monitor are a gas target and a forward tracking detector. Secondary particles emerging from inelastic beam-gas interactions are detected by the tracker. The beam profile is then inferred from the spatial distribution of reconstructed vertices of said interactions. Based on insights and conclusions acquired by a demonstrator device that was operated in the LHC during Run 2, a new design is being developed to fulfill the HL-LHC specifications. This contribution describes the status of the simulation studies being performed to evaluate the impact of design parameters on the instrument’s performance and identify gas target and tracker requirements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB278

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB279

First Tests of Beam Position Monitor Electronics with Bunch Resolving Capabilities

2124

G. Rehm, F. Falkenstern, J. Kuszynski, A. Schälicke
HZB, Berlin, Germany

We are reporting on first tests of a beam position monitor using 1 GS/s data streams of signals from a four button pickup. The system digitizes signals of ~2 GHz bandwidth using a choice of sampling frequency that realizes equivalent time sampling. The data is subsequently processed in the Fourier domain to unfold the aliased spectral lines and apply an impulse response correction per channel. After transforming back into time domain, individual bunch signals can be clearly identified and selected for further processing and decimation. The paper will provide detail on the hardware implementation and demonstrate the bunch resolving capabilities, long term stability and beam intensity dependence using beam tests in BESSY-II and synthetic signals.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB279

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 27 August 2021

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TUPAB280

Quantum Gas Jet Scanner Based Beam Profile Monitors

2128

N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
A quantum gas jet scanner-based beam profile monitor is under development at the Cockcroft Institute (CI), the UK for beam diagnostics based on the principle of ionization detection induced in a quantum gas jet interacting with an ionizing primary beam that shall be characterized. It promises superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. In order to achieve the gas jet with a diameter of less than 100 µm, a novel focusing method exploiting the quantum wave function of the neutral gas atoms, generate an interference pattern with a single maximum acting as an ultra-thin gas jet. An ‘atom sieve’ has been designed for generating the interference pattern, applying the principle of a photon sieve. It will be analogous to a mechanical wire scanner though with a minimal interception. The idea of moving a quantum gas jet through the beam is proposed for transverse profiling. This contribution provides a general overview of the design, working principle, the results obtained from initial measurements carried out at CI and University of Bergen (Norway), for designing the same and possible methods for optimizing the scanner’s design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB280

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 25 August 2021

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TUPAB281

Gas-Mixing to Improve the Resolution of Non-Invasive Gas Jet-Based Ionization Profile Monitors

2132

N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
Ionization beam profile monitor using a supersonic gas jet is an attractive option for the characterization of low and medium energy beams. In this scheme, a primary beam crosses a 45-degree tilted thin gas curtain which causes ionization of gas molecules in the jet. The generated ions are then collected using an electrostatic extraction system to determine the 2D transverse profile of the primary beam. The most commonly used gases for the jet are neon and nitrogen. The signal from the gas jet is always super-imposed with the signal resulting from residual gases in the interaction chamber. CST simulations indicate that the gas jet speed is a key factor for the separation of the jet and the residual gas signals. To obtain a good signal separation, one can increase the velocity of the gas jet. This can be accomplished by generating a gas jet that mixes heavier and lighter gases. This contribution gives a general overview of the monitor design, discusses the effects of gas mixing and CST simulation results. It also presents experimental results obtained with Helium, and Nitrogen, as well as a mixture of them using different percentages and the impact on measurement resolution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB281

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 13 August 2021

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TUPAB282

Optical Beam Loss Monitor Based on Fibres for Beam Loss Monitoring and RF Breakdown Detection

2136

N. Kumar, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from STFC under grant reference ST/V001302/1.
Standard beam loss monitors are used to detect losses at specific locations which is not a practical solution for loss monitoring throughout the whole beam-line. Optical fibre beam loss monitors (oBLMs) are based on the detection of Cherenkov radiation from high energy charged particles having the advantage of covering more than 100 m of an accelerator with a single detector. This system was successfully installed at the Australian Synchrotron covering the entire facility for beam loss measurements. Successful measurements were also demonstrated on the Compact Linear Accelerator for Research and Applications (CLARA), UK with sub-metre beam loss resolution. oBLMs are non-invasive monitors for the detection of the beam loss and RF breakdown within particle accelerators, which has been developed by the QUASAR Group based at the Cockcroft Institute/University of Liverpool, UK in collaboration of D-Beam Ltd, UK. This paper discusses the overview of the system, the incorporation of the monitor into the accelerator diagnostic system, calibration experiment of oBLM and future plans for the system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB282

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 10 August 2021

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TUPAB283

Feasibility Study of ChDR Diagnostic Device in the LHC

2139

K. Łasocha
Jagiellonian University, Kraków, Poland
M. Bergamaschi, M. Krupa, K. Łasocha, T. Lefèvre, S. Mazzoni, N. Mounet, E. Senes
CERN, Geneva, Switzerland
D.M. Harryman
JAI, Egham, Surrey, United Kingdom
P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
A. Potylitsyn
TPU, Tomsk, Russia
A. Schloegelhofer
TU Vienna, Wien, Austria

In recent years Cherenkov Diffraction Radiation (ChDR) has been reported as a phenomenon suitable for various types of particle accelerator diagnostics. As it would typically work best for highly relativistic beam, past studies and experiments have been mostly focusing on the lepton machines. This contribution investigates the prospects on the utilization of ChDR as a diagnostic tool for the Large Hadron Collider (LHC). Based on theoretical considerations and simulation results we estimate the properties of the expected radiation, both in the incoherent and coherent domain, and we compare them with the requirements of the existing diagnostic systems. We also address the potential problem of the use of dielectric radiators in circular machines, where secondary electrons could potentially lead to the creation of electron clouds inside the beam pipe that may affect the radiator.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB283

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paper received ※ 14 May 2021 paper accepted ※ 18 June 2021 issue date ※ 02 September 2021

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TUPAB284

BPM for the High Energy Beam Transport Line of MINERVA Project at SCK•CEN

2143

H. Kraft, L. Perrot
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

This paper presents the status of developments concerning button type BPM. Results of our analytical model BPMOK will compare the measurements done at IPHI facility at CEA-Saclay and GANIL/SPIRAL2 in Caen. The measurements aims to compare the response of the analytical model depending on beam positions, sizes, intensities and energies. BPMOK is validated to predict BPM responses in order to make parametric studies. Starting from already existing BPM built for the MINERVA LINAC, the analytical model is used to design the BPM for the HEBT.

Poster TUPAB284 [1.475 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB284

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paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021

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TUPAB285

Broadband Imaging of Coherent Radiation as a Single-Shot Bunch Length Monitor with Femtosecond Resolution

2147

J. Wolfenden, R.B. Fiorito, E. Kukstas, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M. Brandin, B.S. Kyle, E. Mansten, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden
R.B. Fiorito, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Mansten
Lund University, Division of Atomic Physics, Lund, Sweden
T.H. Pacey
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: This work is supported by the AWAKE-UK project funded by STFC and the STFC Cockcroft core grant No. ST/G008248/1
Bunch length measurements with femtosecond resolution are a key component in the optimisation of beam quality in FELs, storage rings, and plasma-based accelerators. This contribution presents the development of a novel single-shot bunch length monitor with femtosecond resolution, based on broadband imaging of the spatial distribution of emitted coherent radiation. The technique can be applied to many radiation sources; in this study the focus is coherent transition radiation (CTR) at the MAX IV Short Pulse Facility. Bunch lengths of interest at this facility are <100 fs FWHM; therefore the CTR is in the THz to Far-IR range. To this end, a THz imaging system has been developed, utilising high resistivity float zone silicon lenses and a pyroelectric camera; building upon previous results where single-shot compression monitoring was achieved. This contribution presents simulations of this new CTR imaging system to demonstrate the synchrotron radiation mitigation and imaging capability provided, alongside initial measurements and a bunch length fitting algorithm, capable of shot-to-shot operation. A new machine learning analysis method is also discussed.

Poster TUPAB285 [2.008 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB285

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paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 23 August 2021

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TUPAB286

Experience with On-line Optimizers for APS Linac Front End Optimization

2151

H. Shang, M. Borland, X. Huang, Y. Sun
ANL, Lemont, Illinois, USA
M. Song, Z. Zhang
SLAC, Menlo Park, California, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 and BES R&D project FWP 2020-ANL-34573
While the APS linac lattice is set up using a model developed with ELEGANT, the thermionic RF gun front end beam dynamics has been difficult to model. One of the issues is that beam properties from the thermionic gun can vary from time to time. As a result, linac front end beam tuning is required to establish good matching and maximize the charge transported through the linac. We have been using a traditional simplex optimizer to find the best settings for the gun front end magnets and steering magnets. However, it takes a long time and requires some fair initial conditions. Therefore, we imported other on-line optimizers, such as robust conjugate direction search (RCDS) which is a classic optimizer as simplex, multi-objective particle swarm (MOPSO), and multi-generation gaussian process optimizer (MG-GPO) which is based on machine learning technique. In this paper we report our experience with these on-line optimizers for maximum bunch charge transportation efficiency through the linac.

Poster TUPAB286 [2.964 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB286

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paper received ※ 12 May 2021 paper accepted ※ 08 July 2021 issue date ※ 29 August 2021

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TUPAB287

Application of Artificial Neural Network in the APS Linac Bunch Charge Transmission Efficiency

2155

H. Shang, R. Maulik, Y. Sun
ANL, Lemont, Illinois, USA
T. Xu
Northern Illinois University, DeKalb, Illinois, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In recent years there has been a rapid growth in machine learning (ML) and artificial intelligence (AI) applications in accelerators. As the scale of complexity and sophistication of modern accelerators grows, the difficulties in modeling the machine increase greatly in order to include all the interacting subsystems and to consider the limitation of various diagnostics to benchmark against measurements. Tools based on ML can help substantially in revealing correlations of machine condition and beam parameters that are not easily discovered using traditional physics model-based simulations, reducing machine tuning up time etc among the many possible applications. While at APS we have many excellent tools for the optimization, diagnostics, and controls of the accelerators, we do not yet have ML-based tools established. It is our desire to test ML in our machine operation, optimization, and controls. In this paper, we introduce the application of neural networks to the APS linac bunch charge transmission efficiency.

Poster TUPAB287 [0.781 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB287

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paper received ※ 12 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021

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TUPAB289

Towards Hysteresis Aware Bayesian Regression and Optimization

2159

R.J. Roussel
University of Chicago, Chicago, Illinois, USA
A. Hanuka
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. National Science Foundation under Award No. PHY-1549132, the Center for Bright Beams.
Algorithms used today for accelerator optimization assume a simple proportional relationship between an intermediate tuning parameter and the resultant field or mechanism which influences the beam. This neglects the effects of hysteresis, where the magnetic or mechanical response depends not only on the current parameter value, but also on the historical parameter values. This prevents the use of one to one surrogate models, such as Gaussian processes, to assist in optimization when hysteresis effects are not negligible, since identical points in input space no longer correspond to a same point in output space. In this work, we demonstrate how Bayesian inference can be used in conjunction with Gaussian processes to jointly model both the hysteresis cycle of magnetic elements and the beam response. Using this technique we demonstrate how to model the hysteresis cycle of a magnet during accelerator operation in situ by only measuring the beam response, without direct magnetic field measurements. This allows us to quickly build accurate statistical models of the beam response that can be used for rapid tuning of accelerators where hysteresis effects are dominant.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB289

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paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 19 August 2021

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TUPAB290

Demonstration of Machine Learning Front-End Optimization of the Advanced Photon Source Linac

2163

A. Hanuka, J.P. Duris
SLAC, Menlo Park, California, USA
H. Shang, Y. Sun
ANL, Lemont, Illinois, USA

The electron beam for the Advanced Photon Source (APS) at Argonne National Laboratory is generated from a thermionic RF gun and accelerated by an S-band linear accelerator – the APS linac. While the APS linac lattice is set up using a model developed with ELEGANT, the thermionic RF gun front-end beam dynamics have been difficult to model. One of the issues is that beam properties from thermionic guns can vary. As a result, linac front-end beam tuning is required to establish good matching and maximize the charge transported through the linac. A traditional Nelder-Mead simplex optimizer has been used to find the best settings for the sixteen quadrupoles and steering magnets. However, it takes a long time and requires some fair initial conditions. The Gaussian Process (GP) optimizer does not have the initial condition limitation and runs several times faster. In this paper, we report our data collection and analysis for the training of the GP hyperparameters and discuss the application of GP optimizer on the APS linac front-end optimization for maximum bunch charge transportation efficiency through the linac.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB290

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paper received ※ 09 May 2021 paper accepted ※ 28 July 2021 issue date ※ 27 August 2021

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TUPAB291

Subsystem Level Data Acquisition for the Optical Synchronization System at European XFEL

2167

M. Schütte, A. Eichler, T. Lamb, V. Rybnikov, H. Schlarb, T. Wilksen
DESY, Hamburg, Germany

The optical synchronization system for the European X-Ray Free-Electron Laser provides sub-10 femtosecond timing precision * for the accelerator subsystems and experiments. This is achieved by phase locking a mode-locked laser oscillator to the main RF reference and distributing the optical pulse train carrying the time information via actively propagation-time stabilized optical fibers to multiple end-stations. Making up roughly one percent of the entire European XFEL, it is the first subsystem to receive a large-scale data acquisition system [2] for storing not just hand-selected information, but in fact all diagnostic, monitoring, and configuration data relevant to the optical synchronization available from the distributed control system infrastructure. A minimum of 100 TB per year may be stored in a persistent archive for long-term health monitoring and data mining whereas excess data is stored in a short-term ring buffer for high-resolution fault analysis and feature extraction algorithm development. This paper describes scale, challenges and first experiences from the optical synchronization data acquisition system.
* S. Schulz et al., "Few-Femtosecond Facility-Wide Sync. of the European XFEL," in Proc. FEL’19
** T. Wilksen et al., "A Bunch-Sync. DAQ System for the European XFEL," in Proc. ICALEPCS’17

Poster TUPAB291 [0.281 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB291

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paper received ※ 14 May 2021 paper accepted ※ 17 June 2021 issue date ※ 24 August 2021

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TUPAB292

Automation of the ReAccelerator Linac Phasing

2170

D.J. Barofsky, A.I. Henriques, T.J. Kabana, A.S. Plastun
FRIB, East Lansing, Michigan, USA
D.B. Crisp, A. Lapierre, S. Nash, A.C.C. Villari
NSCL, East Lansing, Michigan, USA

Funding: This work is supported by the National Science Foundation under Grant No. PHY-1565546
The ReAccelerator (ReA) at the National Superconducting Cyclotron Laboratory at Michigan State University is a unique facility, as it offers the possibility to reaccelerate not only stable, but rare-isotope beams produced by fast-projectile fragmentation or fission. At ReA, beams are accelerated using a Radio-Frequency-Quadrupole and a superconducting linear accelerator before being delivered to experiments. Beam preparation time plays a major role in the availability of beams to experiments. One of the major time consuming tasks is the linac phasing, since there are 23 resonator cavities to be phased, usually with very low beam intensities. This procedure was automated using a combination of EPICS (Experimental Physics and Industrial Controls System) In/Output Controllers (IOCs) and IOC triggered scripts to scan the resonator phase delay and measure the change in beam energy. We have developed user-friendly tools to phase the linac, which have been tested, making the task of phasing substantially easier. In this presentation, we will present our methodology, challenges faced, tools developed, and initial results of the application for automating the phasing of the ReA linac.

Poster TUPAB292 [1.140 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB292

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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TUPAB295

Upgrade to the EPICS Control System at the Argonne Wakefield Accelerator Test Facility

2173

W. Liu, J.M. Byrd, D.S. Doran, G. Ha, A.N. Johnson, P. Piot, J.G. Power, J.H. Shao, G. Shen, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: US Department of Energy, Office of Science
The Argonne Wakefield Accelerator (AWA) Test Facility has used a completely homebrewed, MS Windows-based control system for the last 20 years. In an effort to modernize the control system and prepare for an active machine learning program, the AWA will work with the Advanced Photon Source (APS) controls group to upgrade its control system to EPICS. The EPICS control system is expected to facilitate collaborations and support the future growth of AWA. An overview of the previous AWA control and data acquisition system is presented, along with a vision and path for completing the EPICS upgrade.

Poster TUPAB295 [1.108 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB295

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021

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TUPAB296

LLRF Upgrade at the Argonne Wakefield Accelerator Test Facility

2176

W. Liu, D.S. Doran, G. Ha, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA
L.R. Doolittle, D. Filippetto, D. Li, S. Paiagua, C. Serrano, V.K. Vytla
LBNL, Berkeley, California, USA

Funding: US Department of Energy, Office of Science
The Argonne Wakefiled Accelerator (AWA) Test Facility designed and operated a homemade LLRF system for the last 20 years. It is based on NI-PXI products that has now become obsolete. The AWA’s LLRF cannot keep up with the increasing stability demands of AWA’s upgraded facility. An overhaul of the system is strongly desired. With the support from DOE-HEP, the AWA is collaborating with Lawrence Berkeley National Laboratory (LBNL)to upgrade its LLRF system with modern instrumentation to meet the growing stability demands. An overview of AWA’s current LLRF system performance is presented together with the upgrade plan and expectations.

Poster TUPAB296 [1.943 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB296

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paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 26 August 2021

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TUPAB297

Data Archive System for Superconducting RIKEN Linear Accelerator at RIBF

2178

A. Uchiyama, N. Fukunishi, M. Kidera, M. Komiyama
RIKEN Nishina Center, Wako, Japan

At RIKEN Nishina Center, superconducting RIKEN Linear Accelerator (SRILAC) was newly installed at downstream of existing accelerator and upgraded for the search experiments of super-heavy-elements with atomic numbers of 119 and higher. For the data archiving and the data visualization in RI Beam Factory (RIBF) project, we have utilized RIBFCAS (RIBF control archive system) since 2009. For the number of archived data point was expected to increase dramatically for SRILAC, we introduced the Archiver Appliance for improvement of the data archiving performance. On the other hand, to realize a user-friendly system about the data visualization, the data of RIBFCAS and the Archiver Appliance should be visualized on the same system. In this system, by implementing a Web application to convert the RIBFCAS data to JSON format, it became possible to unify the data format with the Archiver Appliance and display the data with the same viewer software. In the SRILAC beam commissioning, it became to useful system for finding anomalies and understanding the behavior of superconducting cavity. In this conference, we report the system implementation, developed tool, and the future plan in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB297

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 17 August 2021

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TUPAB298

First Steps Toward an Autonomous Accelerator, a Common Project Between DESY and KIT

2182

A. Eichler, F. Burkart, J. Kaiser, W. Kuropka, O. Stein
DESY, Hamburg, Germany
E. Bründermann, A. Santamaria Garcia, C. Xu
KIT, Karlsruhe, Germany

Funding: Helmholtz Artificial Cooperation Unit
Reinforcement Learning algorithms have risen in popularity in recent years in the accelerator physics community, showing potential in beam control and in the optimization and automation of tasks in accelerator operation. The Helmholtz AI project "Machine Learning toward Autonomous Accelerators" is a collaboration between DESY and KIT that works on investigating and developing RL applications for the automatic start-up of electron linear accelerators. The work is carried out in parallel at two similar research accelerators: ARES at DESY and FLUTE at KIT, giving the unique opportunity of transfer learning between facilities. One of the first steps of this project is the establishment of a common interface between the simulations and the machine, in order to test and apply various optimization approaches interchangeably between the two accelerators. In this paper we present the first results on the common interface and its application to beam focusing in ARES, and the idea of laser shaping with spatial light modulators at FLUTE.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB298

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 17 August 2021

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TUPAB299

Tuned Delay Unit for a Stochastic Cooling System at NICA Collider

2186

S.V. Barabin, T. Kulevoy, D.A. Liakin, A.Y. Orlov
ITEP, Moscow, Russia
I.V. Gorelyshev, K.G. Osipov, V.V. Peshkov, A.O. Sidorin
JINR/VBLHEP, Dubna, Moscow region, Russia

Stochastic cooling is one of the crucial NICA (Nuclotron-based Ion Collider fAcility) subsystems. This system requires fine tuning of the response delay to the kicker, for both longitudinal and transverse stochastic cooling systems. The use of a digital delay line allows to add additional features such as a frequency dependent group velocity correction. To analyse the capabilities of the digital delay unit, a prototype of the device was created and tested. The article presents the characteristics of the prototype, its architecture and principle of operation, test results and estimations for the future developments.

Poster TUPAB299 [0.493 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB299

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paper received ※ 17 May 2021 paper accepted ※ 10 June 2021 issue date ※ 16 August 2021

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TUPAB300

Ion Source Optimization Using Bi-Objective Genetic and Matrix-Profile Algorithm

2190

W. Geithner, Z. Andelkovic, O. Geithner, F. Herfurth, V. Rapp
GSI, Darmstadt, Germany
A. Neméth
Atato, Alzenau, Germany
A. Van Benschoten
MPF, Plymouth, Minnesota, USA
F. Wilhelmstötter
emarsys, Vienna, Austria

Employing the local ECR ion source of the FAIR phase 0 ion storage ring CRYRING@ESR, we set up an IT-environment for on-line data processing and applications based on the data available from beam diagnostic instruments and input signals controlling the ion source. As a first proof of principle, we implemented a closed-loop optimization software controller based on bi-objective Genetic Optimization*. As one property for optimization we used the ion beam current measured with a Faraday-cup detector. As second optimization-property we the on-line processed time-resolved signal of the individual ion-source pulses employing the relatively new Matrix-Profile Algorithm** which provides a measure for the shot-by-shot variability of the consecutive pulses. We will report on the status of the data logging framework, the implementation of related software programs and the results of first tests.
* Wilhelmstötter, F.: Jenetics advanced genetic algorithm, online http://jenetics.io
** Matrix Profile Foundation. Homepage, online https://github.com/matrix-profile-foundation

Poster TUPAB300 [5.485 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB300

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paper received ※ 01 June 2021 paper accepted ※ 21 June 2021 issue date ※ 16 August 2021

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TUPAB302

Arrival Time Stabilization at Flash Using the Bunch Arrival Corrector Cavity (BACCA)

2194

B. Lautenschlager, Ł. Butkowski, M.K. Czwalinna, B. Dursun, M. Hierholzer, S. Pfeiffer, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

For pump-probe and seeding experiments at free electron lasers, a femtosecond precise bunch arrival time stability is mandatory. To stabilize the arrival times a fast longitudinal intra bunch-train feedback (L-IBFB) using bunch arrival time monitors is applied. The electron bunch energy prior to a bunch compression chicane is modulated by superconducting radio frequency (SRF) cavities to compensate fast arrival time fluctuations of the subsequent bunches. A broadband normal conducting RF cavity was installed in front of the first bunch compression chicane at FLASH. The L-IBFB uses the normal conducting cavity for small but fast energy corrections together with the SRF cavities for larger and slower corrections. Current measurements show arrival time stabilities of the electron bunches towards 5 fs (rms) at the end of the linac, if the normal conducting cavity acts together with the SRF cavities in the L-IBFB system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB302

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 26 August 2021

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TUPAB304

Preliminary Investigation of the Noises and Updates on Physics Studies of FOFB in HEPS

2197

X.Y. Huang, Y. Jiaopresenter, Y. Wei
IHEP, Beijing, People’s Republic of China

High Energy Photon Source (HEPS) is a Fourth-generation storage ring light source in China and is under construction. Noises, such as the ambient mechanical vibration and the power supply ripples of magnets, may induce large orbit motions of electron bunches and hence dramatically degrade the emitted photon beam quality. The effect of noises becomes significant and needs to be considered very carefully, especially when the emittances of the electron beam approach the diffraction limit of x-ray. For the HEPS, the noises are modelled and the total beam orbit motion is evaluated considering the spectral characteristics of all the transformation processes from the errors to the orbit. In this paper, we present the preliminary calculation of the effects of noises in HEPS, and the control of the orbit motion with the FOFB system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB304

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paper received ※ 17 May 2021 paper accepted ※ 02 July 2021 issue date ※ 16 August 2021

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TUPAB306

Status of Beam-Based Feedback Research and Development for Continuous Wave SRF Linac ELBE

2200

A. Maalberg, M. Kuntzsch
HZDR, Dresden, Germany
E. Petlenkov
TalTech, Tallinn, Estonia

The superconducting electron linear accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf is a versatile light source operated in continuous wave mode. As the demand on the beam stability increases, the improvement of the beam control schemes currently installed at ELBE becomes highly relevant. This improvement can be achieved by an upgrade of the existing digital MicroTCA.4-based LLRF control scheme by beam-based feedback. By presenting both the design and implementation details of the new control scheme this contribution reports the status of the work in progress.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB306

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB307

Robust Optical Instrumentation for Accelerator Alignment Using Frequency Scanning Interferometry

2203

M. Sosin, H. Mainaud Durand, F. Micolon, V. Rude, J.M. Rutkowski
CERN, Meyrin, Switzerland

The precise alignment of components inside particle accelerators is an important engineering challenge in high-energy physics. Optical interferometry, being a precise, optical distance measurement technique, is often a method of choice in such applications. However, classical fringe-counting interferometers present several drawbacks in terms of system complexity. Due to the increasing availability of broadband, high-speed, sweeping laser sources, Frequency Scanning Interferometry (FSI) based systems, using Fourier analysis of the interference signal, are becoming a subject of growing interest. In the framework of the High-Luminosity LHC project at CERN, a range of FSI-based sensor solutions have been developed and tested. It includes the optical equipment for monitoring the position of cryogenic components inside their cryostats and FSI instrumentation like inclinometers and water-based levelling sensors. This paper presents the results of preliminary tests of these components.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB307

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paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021

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TUPAB308

Mechanical Consolidation of the LHC Inner Triplet Magnet Supporting System for Remote Alignment

2207

F. Micolon, N. Bourcey, J-B. Deschamps, A. Herty, S. Le Naour, T. Mikkola, V. Parma, D. Ramos, V. Rude, M. Sosinpresenter
CERN, Meyrin, Switzerland

Given the high radiation area and the tight alignment tolerances, the LHC inner triplet magnets were designed to be realigned remotely using motorized supporting jacks. However, during run 2 the LHC triplet realignment system started to show an unexpected behavior with erratic load variations on the magnet supporting jacks when operated. It was then decided to freeze any further realignment of the LHC triplet magnet for the remainder of the run. Subsequently, a project team was set up at CERN to understand better the conditions leading to such unexpected behavior and to study and propose a technical consolidation for the realignment system of the LHC triplet magnet. A fully instrumented magnet string using LHC triplet spare magnets was assembled and used at CERN to provide a realistic test bench for this study. This paper reports on the work undertaken to study the triplet magnet overall realignment kinematic, the findings on the readjustment system malfunction and details the consolidation solution implemented for the next LHC run

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB308

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paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 18 August 2021

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TUPAB309

Alignment Verification and Monitoring Strategies for the Sirius Light Source

2210

R. Oliveira Neto, R. Junqueira Leão, L.R. Leão
CNPEM, Campinas, SP, Brazil

The approach for the alignment of Sirius is the use of portable coordinate metrology instruments in a common reference, via a network of stable points previously surveyed. This type of network is composed of a dense distribution of points materialized in the form of embedded target holders on the special slab and radiation shielding. Phenomena such as ground movements, temperature gradients and vibrations could lead to misalignment of the components, possibly causing a degradation in machine performance. Therefore, the relative positions of the accelerator magnets need to be periodically verified along with the structures surrounding it to ensure a good reference to future alignment operations. This paper will present the status of Sirius monitoring systems, including data from the first months of operation of the hydrostatic levelling sensors. Also, possibilities with simplified network measurements for detecting structural deformations and assessing its stability will be presented, along with a proposal of a photogrammetric reconstruction of the alignment profile of the storage ring. Finally, it will be shown a compilation of analysis on the deformation of the Sirius facilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB309

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paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021

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TUPAB310

Establishing a Metrological Reference Network for the Alignment of Sirius

2214

H. Geraissate, G.R. Rovigatti de Oliveira
LNLS, Campinas, Brazil
R. Junqueira Leão
CNPEM, Campinas, SP, Brazil

Sirius is the Brazilian 4th generation synchrotron light source. It consists of three electron accelerators and it has room for up to 38 beamlines. To make the alignment of Sirius components possible, there is a need for a network of points comprising the installation volume, allowing the location of portable coordinate instruments on a common reference frame. This work describes the development of such networks for the whole Sirius facility. The layout of the networks is presented together with the survey strategies. Details are given on how the calculations combined laser trackers and optical level measurements data and how the Earth curvature compensation was performed. A novel laser tracker orientation technique applied for linking networks on different environments is also presented. Finally, the uncertainty estimation for the resulting network and its deformation history is shown.

Poster TUPAB310 [4.084 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB310

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paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 21 August 2021

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TUPAB311

Nonlinear Correctors Tuning for the Collector Ring Isochronous Mode

2218

M.A. Lyalin, I. Koop, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia
I. Koop, M.A. Lyalin, D.B. Shwartz
NSU, Novosibirsk, Russia

One of the operating modes for the Collector Ring (CR) under construction in Darmstadt is the isochronous mode, in which the captured ions circulate with an equal period regardless of their momentum. The measurement of the orbital period T by the time-of-flight sensors makes it possible to precisely determine the mass to the charge ratio of the ion under study. For this, the change of the circulation period dT should not exceed 1·10^-6 for dT/T in the entire momentum acceptance of the 0.62%. Modeling in the Strategic Accelerator Design code showed that without nonlinear effects compensation, the orbital period variation is 1·10^-5. In this work, the parameters of nonlinear correctors, which are sextupoles and octupoles in CR, are determined, necessary for the isochronous mode implementation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB311

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paper received ※ 29 May 2021 paper accepted ※ 16 June 2021 issue date ※ 14 August 2021

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TUPAB313

Arrangement Optimization of Quadrupoles and Correctors for Beam Alignment

2221

L. Xu, Q.M. Zhang
Xi’an Jiaotong University, People’s Republic of China
H.X. Deng
SARI-CAS, Pudong, Shanghai, People’s Republic of China
N. Huang
UCAS, Beijing, People’s Republic of China
N. Huang
SINAP, Shanghai, People’s Republic of China

In the X-ray free-electron laser (XFEL), the alignment and stability of beam orbit have a great impact on power and qualities of the generated X-ray pulses. Currently, the beam-based alignment (BBA) is the most widely used technique in beam alignment. In order to find the best arrangement of quadrupoles and correctors, a mathematical model is established based on the transmission matrix method. With this model, several simple arrangements of quadrupoles and correctors are selected to simulate the beam alignment process. It is found that when two correctors adjust two quadrupoles, the beam can pass through the center of quadrupoles approximately collimated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB313

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paper received ※ 16 May 2021 paper accepted ※ 31 August 2021 issue date ※ 16 August 2021

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TUPAB314

SPS Personnel Protection System: From Design to Commissioning

2224

T. Ladzinski, T. Hakulinen, F. Havart, V. Martins De Sousa Dos Rios, M. Munoz Codoceo, P. Ninin, J.P. Ridewood, E. Sanchez-Corral Mena, D. Vaxelaire
CERN, Meyrin, Switzerland

During the second long shutdown (LS2) of the accelerator complex at CERN, the access system of the Super Proton Synchrotron (SPS) was completely renovated. This complex project was motivated by the technical obsolescence and lack of sufficient redundancy in the existing system, as well as by the need for homogenisation of technologies and practices across the different machines at CERN. The new Personnel Protection System includes 16 state-of-the-art access points making sure that only fully identified, trained and authorised personnel can enter the facility and an interlock system with a rationalized number of safety chains designed to meet the current safety standards. The control part is based on Siemens 1500 series of programmable logic controllers, complemented by a technologically diverse relay logic loop for the critical safety functions. This paper presents the new system and the design choices made to permit fast installation in a period where the access system itself was heavily used to allow vast upgrades of the SPS accelerator and its infrastructure. It also covers the verification and validation methodology and lessons learned during the commissioning phase.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB314

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paper received ※ 14 May 2021 paper accepted ※ 10 June 2021 issue date ※ 22 August 2021

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TUPAB315

Development of Disaster Prevention System for Accelerator Tunnel

2228

K. Ishii, K. Bessho, M. Yoshioka
KEK, Ibaraki, Japan
Y. Kawabata, H. Matsuda, K. Matsumoto
Tobishima Corp., Tokyo, Japan
S. Tagashira
Kansai University, Osaka, Japan
N. Yamamoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Health Labor Sciences Research Grant of Japan
In an enclosed space such as a particle accelerator tunnel, ensuring worker safety during a disaster is an issue of critical importance. It is necessary to have a system in which the manager can know from outside the tunnel whether there is any worker left behind and whether the worker is escaping in the right direction. Because a global positioning system (GPS) is not available in the tunnel, we are developing a disaster prevention system that uses Wi-Fi to transmit the positioning of workers and two-way communication. The Wi-Fi access point (AP) installed in the tunnel should be radiation resistant. Additionally, the equipment carried by the worker is convenient and easy to carry. We tested the radiation hardness of commercial AP devices and developed a smartphone application to perform location information transmission and simultaneous character transmission. In 2019, we installed the system on the J-PARC Main Ring and started its operation. In this paper, the functions of the developed system and its prospects are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB315

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 25 August 2021

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TUPAB316

New Operational Quantities for Radiation Protection by ICRU and ICRP: Impact on Workplaces at Accelerators

2231

Th. Otto, M. Widorski
CERN, Meyrin, Switzerland

In radiation protection, Effective Dose E quantifies stochastic radiation detriment. E is defined as a weighted sum of absorbed dose to organs and tissues and cannot be measured directly. ICRU has defined operational quantities to measure effective dose approximately, such as Ambient dose equivalent H*(10). At high energies, the estimates provided by H*(10) deviate strongly from effective dose. In 2020, ICRU and ICRP have recommended new operational quantities for external radiation with a definition close to the one of effective dose, and published an extensive collection of conversion coefficients from particle fluence to the new quantities (1). Ambient dose H* serves for operational monitoring purposes. The new definition alleviates the observed discrepancies of H*(10) with effective dose. In this paper, we present a numerical study of effective dose E, ambient dose equivalent H*(10) and ambient dose H* in radiation fields at workplaces at proton- and electron accelerators. These places include locations behind primary shielding, in access mazes and in the vicinity of activated accelerator components.
(1) ICRU Report 95, Operational quantities for external radiation

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB316

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paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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TUPAB317

Benchmarking of the Radiation Environment Simulations for CMS Experiment at LHC

2235

I.L. Azhgirey, I.A. Kurochkin, A.D. Riabchikova
IHEP, Moscow Region, Russia
D. Bozzato, A.E. Dabrowski, P. Kicsiny, S. Mallows, J. Wanczyk
CERN, Geneva, Switzerland

Radiation Simulations group of the Beam Radiation Instrumentation and Luminosity Project of the CMS experiment provide for CMS radiation environment and radiation effects simulation and benchmarking of these calculations with CMS data and other data from LHC measuring devices. We present some results of such benchmarking and the reliability analysis of the simulation procedures for radiation environment calculations at the LHC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB317

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021

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TUPAB318

The Beamline Safety Interlock System of Taiwan Photon Source

2239

C.F. Chang, C.Y. Chang, C.Y. Liu, H.Y. Yan
NSRRC, Hsinchu, Taiwan

The energy of synchrotron radiation generated by bremsstrahlung radiation and magnet is rather high, which may cause serious radiation damage to human body or even imperil people’s life. The beamline therefore must be equipped with radiation-protection system; in addition, the overheat of optical components exposed to synchrotron radiation will lead to the damage of optical components and devices. In consequence, the beamline should be furnished with the cooling-protection system to cool down optical components and devices. The Beamline Safety Interlock System targets at protecting the personnel and the safety of devices, limiting the radiation dose to a security value for experimental personnel or staffs exposing to radiation on the site as well as preventing beamline components from being exposed to overheat or vacuum damages to improve the effectiveness of beamline.

Poster TUPAB318 [3.440 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB318

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paper received ※ 09 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021

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TUPAB319

SNS Credited Beam Power Limit System Preliminary Design

2242

C. Deibele
ORNL, Oak Ridge, Tennessee, USA
K.L. Mahoney
ORNL RAD, Oak Ridge, Tennessee, USA

The Controls Group at the Spallation Neutron Source (SNS) is designing a programmable signal processor based credited safety control that calculates pulsed beam power based on beam kinetic energy and charge. The system must reliably shut off the beam if the average power exceeds 2.145 MW averaged over 60 seconds. This paper discusses architecture and design choices needed to develop the system under the auspices of a programmable radiation-safety credit control.

Poster TUPAB319 [1.925 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB319

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paper received ※ 16 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021

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TUPAB320

Physical Design of the Radiation Shielding for the CMS Experiment at LHC

2246

I.L. Azhgirey, I.A. Kurochkin, A.D. Riabchikovapresenter
IHEP, Moscow Region, Russia
D. Bozzato, A.E. Dabrowski, S. Mallows
CERN, Meyrin, Switzerland

The design of the radiation shielding for the CMS experiment at the LHC requires a simulation of the radiation environment using a model of the CMS experimental setup, accelerator components and the experimental hall infrastructure. The radiation simulations are used to optimise the design of the CMS detectors components and also the interface of the CMS detector with LHC accelerator. The Beam Radiation Instrumentation and Luminosity Project of CMS is responsible for giving important input into the optimisation and upgrade of radiation shielding used in CMS and also the radiation environment simulations software infrastructure. This contribution describes the organization of this work, the simulation software environment used for this part of CMS experiment activity and recent radiation simulation results used to optimise the forward shielding for CMS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB320

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 10 August 2021

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TUPAB322

Redesign and Upgrade of the LHC Access Control System

2249

T. Hakulinen, S. Di Luca, G. Godineau, R. Nunes, G. Smith
CERN, Meyrin, Switzerland

The old LHC Access Control System (LACS) was based on a single access control solution, which integrated software and hardware into one monolithic application encompassing all the different subsystems (access control, video surveillance, interphones, biometry, equipment control, safety elements). Both the hardware and software were approaching end-of-life by the vendor before the CERN Long Shutdown 2 (LS2). The new design is based on a distributed approach, where the different subsystems are integrated in a flexible manner with well-defined interfaces, which will permit much easier single sub-system management, upgrades, and even full replacements if necessary. From the system point of view, the focus is on the advantages that this redesign brings to system operation, testing, and management. Procedurally the interest is in the overall management of a very complex in-place upgrade of a system, where the new implementation needed to coexist with the old during its constant simultaneous solicitation over the LS2.

Poster TUPAB322 [6.906 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB322

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paper received ※ 15 May 2021 paper accepted ※ 28 May 2021 issue date ※ 28 August 2021

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TUPAB323

Modular Type Quick Splicing Method for TPS Beamline Radiation Shielding Hutch

2252

C.Y. Chang, C.H. Chang, S.H. Chang, C.L. Chen, Y.C. Linpresenter, J.C. Liu, D.G. Liu, H.Y. Yan
NSRRC, Hsinchu, Taiwan

The synchrotron light source is transported to the experimental station through a beamline with specified optics, such as mask, mirror, slit, monochromator. Generally, standard beamline should use solid materials (stainless steel, tungsten, lead, and PE) to block bremsstrahlung and synchrotron radiations, even the neutron. The radiation-shielded hutch surrounds the peripheral area of the beamline with iron and lead panels. It requires blocking the scattering radiation to protect the person against radiation hazards. A modularized radiation shielding hutch includes the frame, wall, and ceiling cover that can assemble on-site through splicing. This method could greatly shorten the installation. Besides, we designed the modular ceiling cover units with a quick mounting/opening function to easily enable the maintenance and installation of large optical components. The details of the concept design for the fixed-point radiation shielding hutch in the TPS beamline are also reported that includes the configurations of the radiation shielding wall panels, frames, and pipes/cables arrangements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB323

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paper received ※ 13 May 2021 paper accepted ※ 10 June 2021 issue date ※ 21 August 2021

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TUPAB324

Real-Time Radiation Monitoring System with Interlock Protection Mechanism in Taiwan Photon Source

2256

Y.C. Lin, A.Y. Chen, C.-R. Chen, S.J. Huang, S.P. Kao, S.Y. Lin, J.C. Liu, P.J. Wen
NSRRC, Hsinchu, Taiwan

To ensure radiation safety for personnel working in the facility, the Radiation and Operation Safety Division has installed a real-time radiation monitoring system in the working area to monitor gamma rays and neutrons, for which the annual dosage limit is designed to be less than 1 mSv/year. Considering 2000 working hours for users and staff members, we have derived a control dose rate limit 2 µSv/4h for interlock protection. If the accumulated radiation dose monitored with the system exceeds 2µSv within a 4-h counting interval, the radiation monitoring station sends a signal to the interlock system to stop injection until the next counting period interval. This paper introduces the radiation monitoring system and its related design information in Taiwan Photon Source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB324

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paper received ※ 14 May 2021 paper accepted ※ 21 June 2021 issue date ※ 27 August 2021

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TUPAB325

Data-Driven Risk Matrices for CERN’s Accelerators

2260

T. Cartier-Michaud, A. Apollonio, G.B. Blarasin, B. Todd, J.A. Uythoven
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
A risk matrix is a common tool used in risk assessment, defining risk levels with respect to the severity and probability of the occurrence of an undesired event. Risk levels can then be used for different purposes, e.g. defining subsystem reliability or personnel safety requirements. Over the history of the Large Hadron Collider (LHC), several risk matrices have been defined to guide system design. Initially, these were focused on machine protection systems, more recently these have also been used to prioritize consolidation activities. A new data-driven development of risk matrices for CERN’s accelerators is presented in this paper, based on data collected in the CERN Accelerator Fault Tracker (AFT). The data-driven approach improves the granularity of the assessment, and limits uncertainty in the risk estimation, as it is based on operational experience. In this paper the authors introduce the mathematical framework, based on operational failure data, and present the resulting risk matrix for LHC.

Poster TUPAB325 [0.499 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB325

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 17 August 2021

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TUPAB326

Injection Optimization and Study of XiPAF Synchrotron

2264

X.Y. Liu, X. Guan, Y. Li, M.W. Wang, X.W. Wang, H.J. Yao, W.B. Ye, H.J. Zeng, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, M.C. Wang, Z.M. Wang, Y. Yang, M.T. Zhao
NINT, Shannxi, People’s Republic of China

The synchrotron of XiPAF (Xi’an 200MeV proton application Facility) is a compact proton synchrotron, which using H^- stripping injection and phase space painting scheme. Now XiPAF is under commissioning with some achievements, the current intensity after injection reach 43mA, the corresponding particle number is 2.3·10¹¹, and the injection efficiency is 57%. The simulation results by PyOrbit show that the injection efficiency is 77%. In this paper, we report how the injection intensity and efficiency were optimized. We analyzed the difference between simulation and experiments, and quantitatively investigate the factors affecting injection efficiency through experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB326

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paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 22 August 2021

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TUPAB327

Developing Robust Digital Twins and Reinforcement Learning for Accelerator Control Systems at the Fermilab Booster

2268

D.L. Kafkes
Fermilab, Batavia, Illinois, USA
M. Schram
JLab, Newport News, Virginia, USA

Funding: This research was sponsored by the Fermilab Laboratory Directed Research and Development Program under Project ID FNAL-LDRD-2019-027: Accelerator Control with Artificial Intelligence.
We describe the offline machine learning (ML) development for an effort to precisely regulate the Gradient Magnet Power Supply (GMPS) at the Fermilab Booster accelerator complex via a Field-Programmable Gate Array (FPGA). As part of this effort, we created a digital twin of the Booster-GMPS control system by training a Long Short-Term Memory (LSTM) to capture its full dynamics. We outline the path we took to carefully validate our digital twin before deploying it as a reinforcement learning (RL) environment. Additionally, we demonstrate the use of a Deep Q-Network (DQN) policy model with the capability to regulate the GMPS against realistic time-varying perturbations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB327

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paper received ※ 18 May 2021 paper accepted ※ 22 June 2021 issue date ※ 20 August 2021

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TUPAB328

Machine Learning for Time Series Prediction of an Accelerator Beam to Recognize Equipment Malfunction

2272

C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA
W. Blokland, D.L. Brown, F. Liu, C.D. Long, D. Lu, P. Ramuhalli, D.E. Womble, J. Zhang, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy.
The Spallation Neutron Source (SNS) is an accelerator based pulsed neutron source based on a 1 GeV pulsed proton Superconducting Radio Frequency (SRF) linear accelerator (linac). Since beginning high power beam operation in 2006 correlations have been found linking abrupt beam loss events to SRF cavity instabilities. With the planned upgrades to double the beam power we expect increased rates of degradation and the importance of minimizing these beam loss events will become ever more important. To further limit degradation, we are developing machine learning approaches to monitor the beam and to detect, predict and prevent beam loss events. Initial research has shown that precursors to beam loss events are detectable. The initial steps are to use ML-based classification to recognize anomalies and to use Long Short-Term Memory (LSTM) autoencoders to predict beam loss. In this paper, we describe recent progress in applying machine learning for recognizing anomalies and predicting beam loss and present initial results of our research using acquired data from different diagnostics and the Machine Protection System (MPS).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB328

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paper received ※ 23 May 2021 paper accepted ※ 28 May 2021 issue date ※ 15 August 2021

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TUPAB329

Pattern Based Parameter Setup of the SNS Linac

2276

C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA
A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy.
Theoretical and practical aspects of beam tuning procedures used for the SNS linac are discussed. The SNS linac includes two sections of beam acceleration. Acceleration in the first section up to 185.5 MeV is done with a room temperature copper linac which consists of both Drift Tube Linac (DTL) and Coupled Cavity Linac (CCL) Radio Frequency (RF) cavities. The second section consists of 81 Superconducting RF (SRF) cavities which accelerate the beam to the final beam energy of 1 GeV. The linac is currently capable of delivering an average beam power output of 1.44 MW with typical yearly operating hours of around 4500 hours. Due to the high power output and high availability of the linac, activation of accelerator equipment is a significant concern. The linac tuning process consists of three stages: model based setup of amplitudes and phases of the RF cavities, empirical beam loss reduction, and then documentation of the final amplitudes and phases of RF cavities after the empirical tuning. The final step is needed to ensure fast recovery from an SRF cavity failure. This paper discusses models, algorithms, diagnostic tools, software, and practices that are used for these stages.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB329

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paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021

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TUPAB333

Status of PIP-II 650 MHz Prototype Dressed Cavity Qualification

2279

G.V. Eremeev, D.J. Bice, C. Boffo, S.K. Chandrasekaran, S. Cheban, F. Furuta, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, A. Lunin, M. Martinello, N. Nigam, J.P. Ozelis, Y.M. Pischalnikov, K.S. Premo, O.V. Prokofiev, O.V. Pronitchev, G.V. Romanov, N. Solyak, A.I. Sukhanov, G. Wu
Fermilab, Batavia, Illinois, USA
M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava
RRCAT, Indore (M.P.), India
P. Bhattacharyya, S. Ghosh, S. Seth
VECC, Kolkata, India
R. Kumar
BARC, Mumbai, India
J. Lewis, P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Pagani, R. Paparella
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
T. Reid
ANL, Lemont, Illinois, USA
A.D. Shabalina
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Low-beta and high-beta sections of PIP-II linac will use nine low-beta cryomodules with four cavities each and four high-beta cryomodules with six cavities each. These cavities will be produced and qualified in collaboration between Fermilab and the international partner labs. Prior to their installation into prototype cryomodules, several dressed cavities, which include jacketed cavities, high power couplers, and tuners, will be qualified in STC horizontal test bed at Fermilab. After qualification of bare β = 0.9 cavities at Fermilab, several pre-production β = 0.92 and β = 0.61 cavities have been and are being fabricated and qualified. Procurements have also been started for high power couplers and tuners. In this contribution we present the current status of prototype dressed cavity qualification for PIP-II.

Poster TUPAB333 [6.247 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB333

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paper received ※ 23 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021

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TUPAB338

Surface Roughness Reduction of Nb₃Sn Thin Films via Laser Annealing for Superconducting Radio-Frequency Cavities

2283

Z. Sun, M. Ge, M. Liepe, T.E. Oseroff, R.D. Porter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
A.B. Connolly, M.O. Thompson
Cornell University, Ithaca, USA

Superconducting radio frequency (SRF) cavities, a key component of particle accelerators, await new SRF materials beyond the state-of-the-art niobium. Nb₃Sn is one of the most competitive candidates, since it increases the superheating field, allows the operation temperature up to 4K, and improves cavity efficiency. Surface roughness and grain boundaries, however, significantly affect the RF performance of current Nb₃Sn cavities. Here, we explore a post laser annealing technique to reduce the surface roughness. In doing so, we deposited a TiN laser-absorber on Nb₃Sn and Nb surfaces, and then annealed the samples by laser scanning via different laser systems. The Nb₃Sn surface roughness was minimized to 101 nm (Ra) by laser annealing via 308 nm, 35 ns pulses. Surface imaging and Fourier analysis revealed laser annealing is able to remove sharp edges and <1 um wavelength features.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB338

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paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 19 August 2021

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TUPAB339

High Power Test of the Antenna Adjustable Power Coupler for 325 MHz Superconducting Cavities

2286

J.Y. Yoon, E.-S. Kim, C.S. Park, S.H. Park
KUS, Sejong, Republic of Korea
J. Bahng
Korea University Sejong Campus, Sejong, Republic of Korea
E. Kako
KEK, Ibaraki, Japan
K.R. Kim
PAL, Pohang, Republic of Korea

Funding: The Ministry of Education (South Korea)
The power coupler is development at Korea University for a Single Spoke Resonator (SSR) of heavy ion accelerator. Our power coupler is a coaxial capacitive type based on a conventional 3-1/8 inch electronic industries alliance (EIA) 50 Ω coaxial transmission line with a titanium nitride (TiN) coated single ceramic window. A high power test is rectangular test cavity with high vacuum and various measuring equipment, such as an arc detector, a power meter, and an electron pick-up probe. The interlock system under vacuum and arc instrumentations prevent the RF window from breaking the power coupler window during the high power test. We conduct high power tests for more than 12 hrs at 12 kW in a 325 MHz continous wave (CW) mode to verify the performance of the designed power coupler.
*Superconducting, *Power Coupler

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB339

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paper received ※ 12 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021

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TUPAB340

Design of the Magnetic Shielding for 166 MHz and 500 MHz Superconducting RF Cavities at High Energy Photon Source

2289

L. Guo, Y. Chen, J. Li, Z.Q. Li, Q. Ma, P. Zhang, X.Y. Zhang, H.J. Zheng
IHEP, Beijing, People’s Republic of China

Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
Five 166 MHz quarter-wave β=1 superconducting cavities and two 500 MHz single-cell elliptical superconducting cavities have been designed for the storage ring of High Energy Photon Source (HEPS). It is necessary to shield magnetic field for superconducting cavities to reduce the residual surface resistance due to magnetic flux trapping during cavity cool down. The magnetic shielding for both 166 MHz and 500 MHz superconducting cavities have been designed. The residual magnetic field inside the cavities have been calculated by using Opera-3D simulation software. The geographic location of the cavity being installed at the HEPS site and the fringe field of the upstream magnet are considered. These are reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB340

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021

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TUPAB341

Optimization of Two-Cell Cavities for the W and H Working Points of the FCC-ee Considering Higher-Order Mode Effects

2292

S. Udongwo, S.G. Zadeh, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
R. Calaga
CERN, Meyrin, Switzerland

Funding: The European Organization for Nuclear Research (CERN)
The lepton collider of the future circular collider (FCC-ee) aims at conducting precision measurements on the Z, W, and H bosons and the top quark. The present RF baseline considers single-cell cavities at 400 MHz for the high current Z-pole working point, four-cell 400 MHz cavities for the W and H working points, and a hybrid RF system composed of four-cell 400 MHz and five-cell 800 MHz cavities for the high energy tt working point. The W working point has shown limitations in the achievable HOM damping for beam stability requirements using four-cell cavities. A two-cell cavity is studied as an alternative scenario for the current W- and H-RF setups with a special focus on HOM damping during the optimization of the RF geometry.

Poster TUPAB341 [1.580 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB341

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021

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TUPAB342

Preliminary Cryogenic Cold Test Results of the First 9-Cell LSF Shape Cavity

2296

R.L. Geng, W.A. Clemens, R.S. Williams
JLab, Newport News, Virginia, USA
S.A. Belomestnykh
Fermilab, Batavia, Illinois, USA
Y. Fuwa
JAEA/J-PARC, Tokai-mura, Japan
H. Hayano
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Z. Li
SLAC, Menlo Park, California, USA
V.D. Shemelin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supplemental support by US-Japan Collaboration on HEP.
Following successful prototyping and testing of single- & 5-cell LSF shape cavities *, **, the first 9-cell LSF shape cavity LSF9-1 was successfully constructed using an innovative process at JLab with the in-house facilities. The cavity was then shipped to KEK for post-fabrication mechanical adjustment and ILC TDR style treatment and surface processing. Cold testing was carried out at the JLab VTA facility, instrumented with a suite of Kyoto instruments. Favorable values for the bath pressure detuning sensitivity and Lorentz force detuning coefficient were experimentally measured, validating the design improvement in cell stiffeners. Pass-band measurements indicate 4 out of 9 cells reaching gradient capability of > 45 MV/m, including 2 cells reaching 51 MV/m. Cornell OST detectors identified the cell and location responsible for the current hard quench limit. Multipacting-like barriers observed in end cells are investigated both analytically and numerically. The cavity was shipped to FNAL and received a light EP at the joint ANL/FNAL facility for further cold testing at Jlab. Two new 9-cell LSF cavities are being constructed including one made of large-grain niobium material.
* R. L. Geng et al.,WEPWI013, IPAC15.
** R. L. Geng et al., MOP064, SRF’19.

Poster TUPAB342 [1.600 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB342

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paper received ※ 09 May 2021 paper accepted ※ 14 June 2021 issue date ※ 20 August 2021

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TUPAB343

Final Design Studies for the VSR DEMO 1.5 GHz Coupler

2300

E. Sharples-Milne, V. Dürr, P. Echevarria, J. Knobloch, A. Neumann, A.V. Vélez
HZB, Berlin, Germany

With the 1.5 GHz couplers for the Variable pulse length Storage Ring (VSR) DEMO now in the manufacturing stages, the studies that led to the final coupler design will be presented. The system specific constraints and design modifications that combat the challenges of thermomechanical stresses, higher order mode (HOM) propagation and dimensional constraints are explored. This includes S-Parameter analysis, an in-depth study of the coupling factor, and multipacting studies for the average (1.5 kW) and peak (16 kW) power.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB343

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 14 August 2021

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TUPAB344

Evaluation of Anisotropic Magnetoresistive (AMR) Sensors for a Magnetic Field Scanning System for SRF Cavities

2304

I.P. Parajuli, G. Ciovati, J.R. Delayen, A.V. Gurevich
ODU, Norfolk, Virginia, USA
G. Ciovati, J.R. Delayen
JLab, Newport News, Virginia, USA

Funding: Work supported by NSF Grant 100614-010. G. C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the significant causes of residual losses in superconducting radio-frequency (SRF) cavities is trapped magnetic flux. The flux trapping mechanism depends on many factors that include cool-down conditions, surface preparation techniques, and ambient magnetic field orientation. Suitable diagnostic tools are not yet available to quantitatively correlate such factors’ effect on the flux trapping mechanism. A magnetic field scanning system (MFSS) consisting of AMR sensors, fluxgate magnetometers, or Hall probes is recently commissioned to scan the local magnetic field of trapped vortices around 1.3 GHz single-cell SRF cavities. In this contribution, we will present results from sensitivity calibration and the first tests of AMR sensors in the MFSS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB344

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 29 August 2021

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TUPAB345

Availability Modeling of the Solid-State Power Amplifiers for the CERN SPS RF Upgrade

2308

L. Felsberger, A. Apollonio, T. Cartier-Michaud, E. Montesinos, J.C. Oliveira, J.A. Uythoven
CERN, Geneva, Switzerland

Funding: This project has received funding from the Euratom research and training programme 2019-2020 under grant agreement No 945077.
As part of the LHC Injector Upgrade program a complete overhaul of the Super Proton Synchrotron Radio-Frequency (RF) system took place. New cavities have been installed for which the solid-state technology was chosen to deliver a combined RF power of 2 MW from 2560 RF amplifiers. This strategy promises high availability as the system continues operation when some of the amplifiers fail. This study quantifies the operational availability that can be achieved with this new installation. The evaluation is based on a Monte Carlo simulation of the system using the novel AvailSim4 simulation software. A model based on lifetime estimations of the RF modules is compared against data from early operational experience. Sensitivity analyses have been made, that give insight to the chosen operational scenario. With the increasing use of solid-state RF power amplifiers, the findings of this study provide a useful reference for future application of this technology in particle accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB345

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 19 August 2021

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TUPAB346

Development of a 500-MHz 150-kW Solid-State Power Amplifier for High Energy Photon Source

2312

Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao
IHEP, Beijing, People’s Republic of China

A 500-MHz 150-kW solid-state power amplifier (SSA) has been developed to test the 500-MHz normal conducting cavities for High Energy Photon Source (HEPS) booster ring. It will also be used to power normal conducting cavities in the initial beam commissioning stage of the HEPS storage ring. A total number of 96 amplifier modules are combined initially by coaxial and later by waveguide combiners to deliver the 150-kW RF power. The final output is of EIA standard WR1800 rectangular waveguide. Each amplifier module consists four transistors equipped with individual circulator and load and outputs 2-kW RF power. Modularity, redundancy and satisfactory RF performance are demonstrated. In the final stage of HEPS project, this 150-kW amplifier will be modified to a 100-kW amplifier to join the other five 100-kW SSAs for normal operation of the booster cavities. The development and test results are presented in this paper.

Poster TUPAB346 [1.870 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB346

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 15 August 2021

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TUPAB347

Development of a 166-MHz 260-kW Solid-State Power Amplifier for High Energy Photon Source

2315

Y.L. Luo, T.M. Huang, J. Li, H.Y. Lin, Q. Ma, Q.Y. Wang, P. Zhang, F.C. Zhao
IHEP, Beijing, People’s Republic of China

166-MHz 260-kW solid-state power amplifiers have been chosen to drive the 166.6-MHz superconducting cavities for the storage ring of High Energy Photon Source. Highly modular yet compact are desired. A total number of 112 amplifier modules of 3 kW each are combined in a multi-stage power combining topology. The final output is of 9-3/16" 50 Ω coaxial rigid line. Each amplifier module consists of 3 LDMOS transistors with individual circulator and load. Thermal simulations of the amplifier module have been conducted to optimize cooling capabilities for both travelling-wave and full-reflection operation scenarios. High efficiency, sufficient redundancy and excellent RF performances of the 260-kW system are demonstrated. A control system is also integrated and EPICS is used to manage the monitored data. The design and test results of the amplifier system are presented in this paper.

Poster TUPAB347 [1.972 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB347

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021

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TUPAB348

Magnetron R&D for High Efficiency CW RF Sources for Industrial Accelerators

2318

H. Wang, K. Jordan, R.M. Nelson, R.A. Rimmer, S.O. Solomon
JLab, Newport News, Virginia, USA
B.R.L. Coriton, C.P. Moeller, K.A. Thackston
GA, San Diego, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and DOE OS/HEP Accelerator Stewardship award 2019-2021.
The scheme of using high-efficiency magnetrons to drive radiofrequency accelerators has been demonstrated at 2450 MHz in CW mode *. Magnetron test stands at JLab and GA have been set up to further test the noise figure and the locking speed of the injection phase-lock method. For higher power applications, power combining experiments using a TM010 cavity-type combiner and a magic tee for the binary combiner while using a single clean injection signal has been carried out at 2450 MHz. The frequency pulling effect between the magnetron and a low-Q cavity has been shown to enhance the frequency locking bandwidth compared to the injection phase-lock alone. The principle has been studied by the equivalent circuit simulation, analytical model, and finally confirmed experimentally on the magnetrons. Due to the pandemic delay in 2020, the equivalent high power tests using a 75kW, 915MHz industrial magnetron will be done in 2021 and will be reported in a future paper.
* H. Wang, et al, Magnetron R&Ds for High-Efficiency CW RF Sources of Particle Accelerators, WEXXPLS1, proceedings of IPAC 2019, Melbourne, Australia, May 19 -24, 2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB348

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paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB349

High Efficiency, Low Cost RF Sources for Accelerators and Colliders

2322

R.L. Ives, T. Bui, G. Collins, H. Freund, T.W. Habermann, D. Marsden, M.E. Read
CCR, San Mateo, California, USA
B.E. Chase, J. Reid
Fermilab, Batavia, Illinois, USA
N. Chaudhary, J.R. Conant, T. Cox, R. Ho, C. McVey, C.M. Walker
CPI, Palo Alto, California, USA
J.C. Frisch, L. Ma
SLAC, Menlo Park, California, USA
A. Jensen
Leidos Corp, Billerica, MA, USA
J.M. Potter
JP Accelerator Works, Los Alamos, New Mexico, USA
W. Sessions
Georgia Tech Research Institute, Smyrna, Georgia, USA

Funding: U.S. Department of Energy
Calabazas Creek Research, Inc. (CCR) and its collaborators are developing high efficiency, low cost RF sources. Phase and Amplitude Controlled Magnetrons: CCR, Fermilab, and Communications & Power Industries, LLC (CPI) recently developed a 100 kW, 1.3 GHz magnetron system with amplitude and phase control. The system operated at more than 80% efficiency and demonstrated rapid control of amplitude and phase. Multiple Beam Triodes: CCR, in collaboration with CPI and JP Accelerator Works, Inc., is developing 200 kW, pulsed and CW RF sources from 350 to 700 MHz with projected efficiencies exceeding 80% and cost of $0.50/Watt. Prototype tubes are scheduled for tests in spring 2021. High Efficiency Klystrons:CCR, CPI, and Leidos, Inc. are building a 1.3 GHz, 100 kW klystron operating at 80% efficiency. High power testing is scheduled for summer 2021. Multiple Beam IOTs: CCR and Georgia Tech Research Institute are developing MBIOTs with simplified input coupling and high efficiency. Simulations indicate that 3rd harmonic drive power can increase the efficiency 8-10 %. The program is developing a prototype tube to produce 200 kW peak, 100 kW average power at 704 MHz.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB349

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paper received ※ 18 May 2021 paper accepted ※ 01 June 2021 issue date ※ 27 August 2021

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TUPAB350

Design of 71 MHz Power Amplifier in a Single-ended Architecture for IRANCYC-10 Cyclotron

2325

F. Babagoli Moziraji, H. Afarideh
AUT, Tehran, Iran
M. Dehghan
Shahid Beheshti University, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

In this paper, the design and simulation of a high power amplifier to provide the required power of a cyclotron accelerator (IRANCYC-10) is presented step-by-step. By combining four modules of this amplifier, a power of 2.5 kW can be achieved to start the main power amplifier. The single ended designs amplifier can generate 1 kW the operating frequency of 71MHz continuous wave (CW). The purpose of choosing this type of design is simplicity to build without the need for a balun, low weight to build high power, as well as cost-effectiveness. The gain and PAE of the SSPA are 21.21 and 71%, respectively. There are also ways to reduce the size of the amplifier.

Poster TUPAB350 [1.008 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB350

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paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 11 August 2021

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TUPAB351

The Progress of 300 kW Home-Made Fully Solid-State Transmitter for TPS

2328

T.-C. Yu, F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

To support the stable operation of Taiwan Photon Source (TPS) with 500mA beam current and the in-creasing beam line construction, a 3rd RF plant is thus constructed for such demand. The RF power source of the other 2 RF plants adopts klystron type transmitter and the 3rd RF plants is transferred to new technology of solid-state for better redundancy and easier mainte-nance. Base on the success of solid-state power ampli-fier development in 2020, a 3rd RF power source is thus decided to be made in house by solid-state tech-nology. The 500MHz 300kW solid-state transmitter is constructed by 4 80 kW solid-state power amplifier (SSPA) towers and power combined by 3 WR1800 3-dB hybrid couplers. Each tower is consisted of 110 850W final stage SSPA modules with 4 100W pre-amplifiers and 6 600W drive amplifiers. The pre and drive amplifiers are power combined for higher redun-dancy. The DC power are economical industrial 48V AC-DC rack mount power supplies which are parallel connected for higher total DC power and best redun-dancy. The architecture and present progress are pre-sented in this article.

Poster TUPAB351 [2.348 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB351

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paper received ※ 20 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021

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TUPAB353

Remote Commissioning of 400 kW 352 MHz Amplifiers

2332

C. Pasotti, A. Cuttin, A. Fabris
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Frizzi, G. Zardi
Itelco Broadcast Srl, Orvieto (TR), Italy
M. Rossi
DB Science, Padova, Italy

In the framework of the European Spallation Source ERIC (ESS ERIC) In-Kind collaboration, Elettra Sincrotrone Trieste has the task to deliver 26 400 kW 352 MHz Radio Frequency Power Station (RFPS) units. They will feed the Spoke Cavities section of the proton Linac. The RFPS manufacturing contract has been awarded to the European Science Solutions consortium (ESS-C) gained the. The production of the amplifiers is well underway and it has reached a steady rate of delivery. Each RFPS is subject to a Factory Acceptance Test (FAT). In this contribution, the main results of the FATs are presented, together with the FAT remote session protocol. This protocol has been specifically developed to cope with the traveling and in persons meeting restrictions imposed by the COVID-19 pandemic.

Poster TUPAB353 [2.675 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB353

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paper received ※ 17 May 2021 paper accepted ※ 23 June 2021 issue date ※ 17 August 2021

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TUPAB354

352-MHz Solid State RF System Development at the Advanced Photon Source

2335

D. Horan, D.J. Bromberek, N.P. DiMonte, A. Goel, T.J. Madden, A. Nassiri, G. Trento, G.J. Waldschmidt
ANL, Lemont, Illinois, USA

Development effort is underway on a 352MHz, 200kW solid state rf system intended as the base design to replace the existing klystron-based rf systems presently in use at the Advanced Photon Source (APS). A sixteen-input, 200kW final combining cavity was designed, built, and successfully tested to 29kW CW in combiner mode, and to 200kW CW in back-feed mode, where an external klystron was used to transmit power into the combining cavity. A four-port waveguide combiner was also tested in both backfeed and combiner mode to 193kW and 26kW respectively. Slow and fast interlock systems were designed and implemented to support the testing process. An EPICS and Programmable Logic Controller (PLC)-based system was developed to control, communicate with, and monitor the rf amplifiers used in the combiner-mode test, and to monitor and log system performance parameters relating to the combining cavity. Low-level rf control of the cavity in 29kW combiner-mode operation was achieved using the existing APS analog low-level rf hardware. Test data and design details are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB354

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 19 August 2021

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TUPAB355

Design and Implementation of a Production Model Bias Tee

2339

T.L. Larter, E. Gutierrez, S.H. Kim, D.G. Morris, J.T. Popielarski, T. Xu, S. Zhao
FRIB, East Lansing, Michigan, USA

Funding: This work is supported by the US Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) includes two types of half wave SC resonators (HWR) operating at 322MHz. The fundamental power couplers used to transmit RF power into the HWRs commonly suffer from multipacting which can result in long conditioning times. A bias tee can be used to apply a high voltage to the couplers to help alleviate multipacting. A production version of the bias tee was commissioned for use at FRIB. The bias tee went through several design revisions to diagnose and correct thermal dissipation issues. This paper will discuss details of design and challenges faced during production validation of the bias tee.

Poster TUPAB355 [0.630 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB355

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paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 12 August 2021

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TUPAB356

Electron Beam Driven Cavities

2342

M. Schuett, U. Ratzinger
IAP, Frankfurt am Main, Germany

State of the art high power feeder for RF cavities used as accelerators generally require RF amplifiers consisting of a vacuum tube, such as a klystron or Grid Tubes. In addition, a number of cost intensive RF auxiliary devices are needed: Modulator, waveguides, circulator, power dump and couplers. The equipment requires significant floor space within the linac building. Alternatively, we propose a direct driven system. Aμbunched electron beam is injected directly into the cavity. A high perveance bunched electron beam can be generated by a standard electron gun combined with a deflecting beam chopper*, an off-the-shelf IOT or klystron, respectively. The pulse rate is determined by the resonance frequency of the cavity. The resonator hereby acts like the output cavity of a klystron: Within its propagation through the cavity the beam is decelerated increasing the stored energy of the accelerator. We present 3D particle PIC simulations evaluating the geometry and beam properties in order to optimize the coupling efficiency and cavity excitation of state-of-art CH particle accelerator structures.
* S. Setzer, T. Weiland and U. Ratzinger, A Chopped Electron Beam Driver for H-Type Cavities, 20th ‘International Linac Conference, Monterey, California, August 21-25, 2000, pp. 1001-1003

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB356

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 11 August 2021

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TUPAB357

Development of the X-Band Megawatt-Class Coaxial Magnetrons

2346

J.Y. Liu, H.B. Chen, Y.S. Han, J. Shi, C.-X. Tang, C.J. Wang, J. Wang, H. Zha
TUB, Beijing, People’s Republic of China

X-band coaxial magnetrons are preferred for industrial and medical accelerators owing to the compact size, low cost and high efficiency. A conditioning and high power test stand for X-band magnetrons has been built in Tsinghua University. Two X-band magnetrons named "MGT-1#" and "MGT-2#" were tested at this stand. The maximum anode currents of both magnetrons reached 100 A after the conditioning process. Maximum peak output power of 1.71 MW and 1.89 MW was achieved for "MGT-1#" and "MGT-2#", respectively. The efficiencies of the two magnetrons are both about 50%.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB357

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021

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TUPAB358

Novel 500 MHz Solid State Power Amplifier Module Development at Sirius

2349

M.H. Wallner, R.H. Farias, A.P.B. Lima, F. Santiago de Oliveira
LNLS, Campinas, Brazil

A new solid state power amplifier (SSPA) module is being developed at the Brazilian Center for Research in Energy and Materials (CNPEM) to drive one of the superconducting RF cavities to be installed at Sirius, its new 3 GeV fourth generation synchrotron light source. Several prototypes have been built and tested in-house, and a planar balun was designed to achieve a push-pull configuration at deep class AB operation. Efforts to optimize heat exchange in various ways have been made. Results obtained thus far are presented and the next steps concerning development are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB358

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021

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TUPAB359

Magnetic Field Measurement and Beam Performance Test of Ceramics Chamber with Integrated Pulsed Magnet at KEK-PF

2352

Y. Lu
Sokendai, Ibaraki, Japan
K. Harada, Y. Kobayashi, C. Mitsuda, S. Nagahashi, T. Nogami, T. Obina, R. Takai, H. Takaki, T. Uchiyama, A. Ueda
KEK, Ibaraki, Japan

An air-core magnet named Ceramics Chamber with integrated Pulsed Magnet(CCiPM) is being developed at the photon factory of KEK(KEK-PF), which will have several applications for the future light source. One prototype has been developed as a dipole kicker, whose bore is only 30mm. Due to the type and structure, it’s expected to have strong magnetic field and high repetition rate. After finishing the offline measurement of magnetic field and evaluation of vacuum tightness, the CCiPM was installed in the beam transport-dump line of PF to have an online beam performance and durability test. The results of the magnetic field measurement and beam performance test will be reviewed.

Poster TUPAB359 [1.164 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB359

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 16 August 2021

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TUPAB361

Study and Design of a Fast Switching Magnet for the MYRRHA Project

2356

E. Froidefond, F. Bouly, P.-O. Dumont
LPSC, Grenoble Cedex, France
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: Work supported by SCK•CEN, CNRS/IN2P3, Univ. Grenoble Alpes.
The MYRRHA project aims at building an Accelerator Driven System demonstrator, which consists of two injectors and a superconducting linac. The proton beam from the first injector accelerated up to 17 MeV goes to the linac (600 MeV) through a Medium Energy Beam Transfer line (MEBT). Whereas in the meantime, the beam from the second injector is sent to a beam dump. In case of failure in the first injector, the beam of the awaiting injector is sent to the linac. A switching magnet located at the junction of the two injection lines performs this beam switch in less than 1.5 seconds. A magnetic design and a mechanical structure of this magnet proposed to the MYRRHA project are presented.
*emmanuel.froidefond@lpsc.in2p3.fr

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB361

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021

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TUPAB362

Physical Design of Electrostatic Deflector in CSNS Muon Source

2360

Y.W. Wu, S. Li, J.Y. Tang, X. Wu
IHEP, Beijing, People’s Republic of China
C.D. Deng, Y. Hong
DNSC, Dongguan, People’s Republic of China
Y.Q. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

CSNS will build a muon source at the end of the RTBT. In the current design, the muon source propose two schemes, namely the baseline scheme and the baby scheme. High voltage electrostatic deflectors (ESD) are used to deflect the beam in the two schemes. A three-channel ESD with 400 kV HV is employed in the baseline scheme and a 210 kV dual-channel ESD in the simplified scheme. According to physical requirements, the electric field concentration factor is introduced, and the electrode of ESD is theoretically designed. 2D and 3D simulations are carried out to analyze the characteristics of electric field distribution by OPERA. The geometry of the electrodes also met the requirements of electric field uniformity, high voltage resistance and mechanical strength at the same time. In the baseline scheme and the baby scheme, the ESD electric field concentration factors are 1.36 and 1.53, and the maximum electric field is 6.78MV/m and 4.6MV/m, respectively. The design meets the requirements and is reasonably feasible.

Poster TUPAB362 [2.214 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB362

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paper received ※ 13 May 2021 paper accepted ※ 09 June 2021 issue date ※ 22 August 2021

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TUPAB363

Feasibility Study for the Novel CERN PS Fast Extraction Septum

2363

T. Helseth, M.G. Atanasov, B. Balhan, J.C.C.M. Borburgh, L. Ducimetière, M.A. Fraser, T. Kramer
CERN, Geneva, Switzerland

In the framework of accelerator consolidation, a feasibility study for a novel CERN PS extraction septum has been conducted. Functional requirements have been established and, accordingly, a system of two septa magnets and their associated pulse generator is proposed. The magnetic septum design is based on eddy current topology. Magnetic simulations in Flux 2D and Opera 3D of a conceptual design have been carried out. The short length and high amplitude of the current pulse required to drive the eddy current septa imply that none of the power converters currently used for septa magnets at CERN will be suitable. Pulse generator topologies derived from kicker generators have therefore been explored and simulated in Spice. The conceptual magnet and generator design along with simulation results are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB363

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021

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TUPAB364

Dipole CR FAIR

2367

K.K. Riabchenko, A.Yu. Pakhomov, T.V. Rybitskaya, A.A. Starostenko, A.S. Tsyganov, K.V. Zhiliaev
BINP SB RAS, Novosibirsk, Russia

The design of CR dipole magnets (24+2 pieces) for the FAIR project in Germany began in 2014 at BINP. CR is a special storage ring where the main emphasis is placed on efficient stochastic pre-cooling of intense beams of stable ions, rare isotopes, or antiprotons. This type of magnet is an iron-based electromagnet with a straight pole, sector form is realized by cutting ends. The maximum field value is 1.6 T. The integrated over the length of the magnet field quality as a function of radius is dBl/Bl = ± 10^-4 with 190 mm good field region as required from the beam dynamics simulations. This challenging field quality is necessary mainly for precise experiments with ion beam in the ISO regime. Below 1.6 T the value dBl/Bl can be higher with a linear approximation up to ± 2.5× 10^-4 at the field level of 0.8 T. The first prototype has been manufactured at the end of 2020. Here we describe features of the dipole, 3D calculations, and measurements of the magnetic field.

Poster TUPAB364 [1.587 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB364

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paper received ※ 09 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021

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TUPAB365

Demonstration of ‘ZEPTO’ Permanent Magnet Technology on Diamond Light Source

2370

A.R. Bainbridge, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Krumpa
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
I.P.S. Martin, W. Tizzano
DLS, Oxfordshire, United Kingdom

The use of permanent magnets (PM’s) in place of traditional electromagnets is becoming more common in accelerator systems around the world. This change is being driven by the desire to reduce both the energy costs and carbon footprint of accelerators. However, the problem remains that it is difficult to adjust the field strength of PM systems. STFC and CERN have a longstanding collaboration in the Zero-Power Tuneable Optics (ZEPTO) project which aims to develop PM systems that are tuneable via moving the PM blocks within a static pole structure. This collaboration has previously produced 3 prototype magnets (2 quadrupoles and 1 dipole) for the proposed CLIC accelerator and aims to expand suitability to a variety of accelerators. We are now demonstrating this technology on a real machine by installing a ZEPTO magnet on Diamond Light Source. We outline the design, construction, and improvement of this technology demonstrator, highlighting the innovations over previous generations of ZEPTO technology that account for previously observed drawbacks.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB365

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paper received ※ 18 May 2021 paper accepted ※ 22 June 2021 issue date ※ 12 August 2021

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TUPAB366

Design and Realization of New Solenoids for High Brightness Electron Beam Injectors

2374

A. Vannozzi, D. Alesini, A. Giribono, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy

High-brightness, high-current electron beams are the main requirement for fourth generation light sources such as free-electron lasers (FELs), energy recovery Linacs (ERLs) and high-energy linear colliders. The most successful device for producing such beams is the Radio-Frequency photoinjector where a key element is the gun solenoid. Its main task is to limit the beam emittance growth in the first acceleration stages by imposing a spiraling motion to the beam. This paper is focused on two magnets: the first one is the solenoid gun for the new photoinjector at INFN-LNF SPARC_LAB test facility. The design, the realization, and all the measurements performed at the factory and at LNF are shown. Moreover, the design of a solenoid for a novel C-band gun for CompactLight project is presented. Both magnets have been designed with the goal to reach the same integrated field of the gun solenoid currently installed at SPARC_LAB, with an integrated field quality of 5·10^-4 in a good field radius of 30mm and 10mm radius respectively for SPARC_LAB and CompactLight solenoid. This one is equipped with a bucking coil to limit the field on cathode that could led to an undesired emittance growth.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB366

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 15 August 2021

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TUPAB368

Design of the Longitudinal Gradient Dipole Magnets for HALF

2378

M.Y. Mingyao
Wang, Hefei, People’s Republic of China
G.Y. Feng, Z.L. Ren, H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Hefei Advanced Light Facility (HALF) is the fourth generation diffraction-limited storage ring light source project in China. The lattice of the storage ring consists of six different dipoles with longitudinal gradients. The longitudinal-gradient dipoles (LGBs) are permanent magnets. This paper presents the designed construction of LGBs and the magnetic field results using OPERA3D. By optimizing the shape of the polar surface, the magnetic field uniformity is optimized to about 5×10^-4. With some movable adjusting block, the magnetic field can be controlled accurately. The temperature stability of the magnet is better than 0.0074 T*mm/°C by setting temperature compensating shunt.

Poster TUPAB368 [0.862 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB368

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paper received ※ 15 May 2021 paper accepted ※ 02 June 2021 issue date ※ 10 August 2021

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TUPAB369

A Fast Non-Linear Model for the EBS Combined Sextupole-Corrector Magnets

2381

G. Le Bec
ESRF, Grenoble, France

Corrector are often integrated in higher order accelerator magnets. In the new ESRF-EBS storage ring, the sextupoles include additional windings allowing for dipole and skew quadrupole corrections. The accurate modelization of such magnets is not as trivial as it may appear, due to their non-linearities and to the crosstalk between their channels. Changing any corrector current induce non-linear errors in the other corrector channels and in the main sextupole strength, making difficult the trimming of the magnets. A model based on a non-linear excitation curve and quadratic contributions from corrector currents was developed. This model is very fast and was included in the accelerator control system to compute the corrector currents in real-time. It was tested against 3D magnetic simulations and magnetic measurements and compared to a simpler matrix-based model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB369

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paper received ※ 17 May 2021 paper accepted ※ 31 August 2021 issue date ※ 22 August 2021

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TUPAB370

Development of Long Coil Dynamic Magnetic Field Measurement System for Dipole Magnets of HEPS Booster

2384

Y.Q. Liu, C.D. Deng, W. Kang, L. Li, S. Li, X. Wu, Y.W. Wupresenter, J.X. Zhou
IHEP, Beijing, People’s Republic of China
C.D. Deng, Y.W. Wupresenter
DNSC, Dongguan, People’s Republic of China

A magnetic field measurement system for dipole magnets of High Energy Photon Source Booster is designed and developed. The system uses the long coil upflow method to measure the dynamic integral field of the magnet, and the long coil transverse-translation method to measure the integral field distribution error of the magnet. In this paper, the design and implementation of the magnetic measuring system are introduced in detail, and the magnetic field measurement results of the prototype magnet are shown. The measurement results show that the repeatability of the dynamic integral field measurement system is about 2 in 10,000, and the repeatability of the uniform distribution of the integral field is better than 1 in 10,000, which meets the test requirements of the discrete integral field of bulk magnets ±1 parts per thousand and the uniformity of the integral field ±5×10-4@6GeV and ±1×10^-3 @0.5GeV.

Poster TUPAB370 [1.475 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB370

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paper received ※ 16 May 2021 paper accepted ※ 16 June 2021 issue date ※ 17 August 2021

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TUPAB372

Status of the Quadrupole Doublet Module Series Manfacturing

2388

T. Winkler, A. Bleile, L.H.J. Bozyk, V.I. Datskov, J. Ketter, P. Kowina, J.P. Meier, N. Pyka, C. Roux, P.J. Spiller, K. Sugita, A. Waldt, St. Wilfert
GSI, Darmstadt, Germany

The 83 Quadrupole Doublet Modules (QDM) for the heavy-ion-synchrotron SIS100 of the FAIR project at GSI are highly integrated cryogenic modules containing multiple magnets. Each of eleven different QDM types consists of two units, where one unit consists of one quadrupole magnet as well as corrector magnets depending on the modules position in the accelerator Ion-Optical Lattice. Additionally, the QDMs contain cryogenic collimators, beam diagnostics, as well as cryogenic UHV beam pipes. The modules contain parts from multiple suppliers increasing the logistics behinds the QDMs design further. We present the process of the module integration, give details on the current integration status and present an outlook on the timeline for the QDM integration planning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB372

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 21 August 2021

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TUPAB373

Design of a Delta-type Superconducting Undulator at the IHEP

2391

J.H. Wei
IHEP CSNS, Guangdong Province, People’s Republic of China
C.D. Deng
DNSC, Dongguan, People’s Republic of China
L. Gong, X.Y. Li, X.C. Yang
IHEP, Beijing, People’s Republic of China
Y. Li
DESY, Hamburg, Germany

Undulators play an important role in the 4th generation radiation light source. In order to satisfy different requirements of the experiments, various undulator structures have been proposed. The Delta-type undulator can provide circular polarized radiation. Conventional undulators are usually made of permanent magnets, but the application of the superconducting technology in the undulator is developing quickly. Compared to the permanent magnet undulators, superconducting undulators can provide higher photon flux with the same magnetic pole gap and period length, especially when the period length is longer than 20 mm. An R&D project is underway to produce a protype of a Delta-type superconducting undulator with 28 mm long period and 12 mm gap at the IHEP. The structure design and the simulation results of the magnetic field are presented in this paper.

Poster TUPAB373 [1.752 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB373

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 15 August 2021

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TUPAB374

Development of a Quench Detection System for the FAIR Superconducting Devices

2394

V. Raginel, M. Dziewiecki, W. Freisleben, P.B. Szwangruber, L. Theiner
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR), which is presently under construction in Darmstadt (Germany), will incorporate a large variety of superconducting devices like magnets, currents leads and bus bars. These components depend on an active protection in case of a transition from superconducting to the resistive state, so-called quench. In this framework, a FAIR Quench Detection System (F-QDS) is being developed based on analog and digital electronics and will be implemented in several machines of the FAIR complex. This paper describes the development of the F-QDS. An overview of the F-QDS electronics is given followed by a description of the system integration to the infrastructure of various machines. Initial test results of the F-QDS prototype system are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB374

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paper received ※ 25 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

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TUPAB375

Commissioning and Operation of Superconducting Multipole Wiggler at Siam Photon Source

2398

P. Sunwong, S. Boonsuya, S. Chaichuay, T. Chanwattana, Ch. Dhammatong, A. Kwankasem, C.P. Preecha, T. Pulampong, K. Sittisard, V. Sooksrimuang, S. Srichan, P. Sudmuang, N. Suradet, S. Tancharakorn
SLRI, Nakhon Ratchasima, Thailand

A new insertion device, Superconducting Multipole Wiggler (SMPW) with the peak field strength of 3.5 T, was installed in the storage ring of Siam Photon Source as a radiation source for a new hard X-ray beamline. Cool-down process, as well as magnet training, was performed with careful tuning of liquid helium filling procedure for efficient management of liquid helium supply. The filling procedure was also optimized for safe operation of the magnet. The SMPW commission-ing was successfully carried out with electron beam and the effect of SMPW on electron beam dynamics was observed. It can be minimized using quadrupole magnets and horizontal/vertical correctors.

Poster TUPAB375 [1.160 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB375

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 31 August 2021

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TUPAB378

Superconducting Dipole Magnets for the SIS100 Synchrotron

2401

F. Kaether, P. Aguar Bartolome, A. Bleile, G. Golluccio, J. Ketter, P. Kosek, F. Kurian, V. Marusov, J.P. Meier, S.S. Mohite, C. Roux, P.J. Spiller, K. Sugita, A. Szwangruber, P.B. Szwangruber, A. Warth, H.G. Weiss
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR) is currently under construction at GSI Darmstadt, Germany. For its main accelarator, the SIS100 synchrotron, 110 superconducting dipole magnets has been produced and extensively tested. The fast-ramped Nuclotron-type superferric dipoles were manufactured with high effort regarding a precise magnetic field which could be proven by magnetic field measurements with high accuracy. Stable operation conditions at 4.5 K were achieved including an excellent quench behaviour and precise geometrical and electrical properties. An overview on design, production, operation, tests and measurement results will be given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB378

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 10 August 2021

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TUPAB379

Superconducting Magnets for Super-FRS: Production and Testing Status

2405

H. Müller, A. Chiuchiolo, E.J. Cho, G. Golluccio, F. Greiner, P. Kosek, M. Michels, C. Roux, K. Sugita, V.V. Velonas, M. Winkler
GSI, Darmstadt, Germany
H. Allain, A. Madur
CEA-IRFU, Gif-sur-Yvette, France
A. Borceto, G. Drago, G. Valesi
ASG, Genova, Italy
M. Garcia Escudero, M. Lopez, J. Lucas
Elytt Energy, Madrid, Spain
G. Riddone, S. Russenschuck
CERN, Geneva, Switzerland

The Super FRS is a two-stage in flight separator to be built next to the site of GSI, Darmstadt, Germany as part of FAIR (Facility for Anti-proton and Ion Research). Its three branches allow to carry out a wide variety of experiments. Due to the large acceptance needed, the magnets of the Super-FRS require a large aperture and therefore only a superconducting solution is feasible. A superferric design was chosen in which the magnetic field is shaped by an iron yoke. For the dipole magnets only the superconducting coils are in a cryostat. These magnets are manufactured by Elytt Energy (Spain). The multiplets, assemblies of quadrupoles and higher order multipole magnets, are completely immersed in a liquid Helium bath. They are being built at ASG (Italy). The first of two first of series multiplets, a short assembly containing 2 magnets, was tested at a dedicated test facility at CERN (Switzerland). The 2nd FoS multiplet, containing 9 magnets, and the FoS dipole will be tested soon. Series production of the multiplets has started. In this paper we will present the status of production and testing of the different superconducting magnets for Super-FRS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB379

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paper received ※ 19 May 2021 paper accepted ※ 31 August 2021 issue date ※ 16 August 2021

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TUPAB380

Testing of the First of Series Quadrupole Doublet Module for the SIS100 Synchrotron

2409

P. Aguar Bartolome, M. Al Ghanem, M. Becker, A. Bleile, R. Bluemel, L.H.J. Bozyk, V.I. Datskov, W. Freisleben, A. Kario, P. Kowina, K.K. Kozlowski, F. Kurian, S. Lindner, J.P. Meier, T. Miertsch, S.S. Mohite, V.P. Plyusnin, I. Pongrac, C. Roux, C. Schroeder, P.J. Spiller, K. Sugita, A. Szwangruber, P.B. Szwangruber, F. Walter, H. Welker, St. Wilfert, T. Winkler, S. Zeller
GSI, Darmstadt, Germany

A new international facility for antiproton and ion research (FAIR) is currently under construction in Darmstadt, Germany. The high intensity primary beam required for different research experiments will be provided by the SIS100 heavy ion synchrotron. The synchrotron is composed of fast cycling superconducting magnets from which about 300 will be integrated in Quadrupole Doublet Modules (QDM). Each module consists of two units composed of a quadrupole and corrector magnets. The First of Series Quadrupole Doublet Module was delivered to the test facility at GSI in November 2019. The assembled doublet was subjected to a dedicated test program to verify the functionality of the module components at cryogenic temperature and operating conditions. The results obtained during the testing campaign will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB380

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 02 September 2021

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TUPAB381

Thermal Analysis of the RHIC Arc Dipole Magnet Cold Mass with the EIC Beam Screen

2413

S.K. Nayak, M. Anerella, M. Blaskiewicz, J.M. Brennan, R.C. Gupta, M. Mapes, G.T. McIntyre, S. Peggs, R. Than, J.E. Tuozzolo, S. Verdú-Andrés, D. Weiss
BNL, Upton, New York, USA

Funding: Funding agency Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The EIC will make use of the existing RHIC storage rings with their superconducting (SC) magnet arcs. A stainless-steel beam screen with co-laminated copper and a thin amorphous carbon (aC) film on the inner surface will be installed in the beam pipe of the SC magnets. The copper will reduce the beam-induced resistive-wall (RW) heating from operation with the higher intensity EIC beams, that if not addressed would make the magnets quench. Limiting the RW heating is also important to achieve an adequately low vacuum level. The aC coating will reduce secondary electron yield which could also cause heating and limit intensity. Among all the RHIC SC magnets, the arc dipoles present the biggest challenge to the design and installation of beam screens. The arc dipoles, which make up for 78% (2.5 km) length of all SC magnets in RHIC, expect the largest RW heating due to their smallest aperture. These magnets are also the longest (9.45 m each), thus experiencing the largest temperature rise over their length, and have a large sagitta (48.5 mm) that increases the difficulty to install the beam screen in place. This paper presents a detailed thermal analysis of the magnet-screen system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB381

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paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 23 August 2021

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TUPAB383

Magnetic Field Performance of the First Serial Quadrupole Units for the SIS100 Synchrotron of FAIR

2417

V.V. Borisov, O. Golubitsky, H.G. Khodzhibagiyan, B.Yu. Kondratiev, M.M. Shandov
JINR, Dubna, Moscow Region, Russia
E.S. Fischer, M.A. Kashunin, S.A. Kostromin, I. Nikolaichuk, T. Parfylo, A.V. Shemchuk, D.A. Zolotykh
JINR/VBLHEP, Dubna, Moscow region, Russia

The FAIR project is a new international accelerator complex, currently under construction in Darmstadt, Germany. The heavy-ion synchrotron SIS100 is the main accelerator of the whole complex. It will provide high-intensity primary beams with a magnetic rigidity of 100 Tm and a maximum repetition rate up to 4 Hz. The series production and testing of superconducting quadrupole units began in 2020 at JINR, Dubna. The first batch of units was delivered to Germany in September 2020. Each unit is subjected to a comprehensive testing program both at ambient temperature and under cryogenic conditions. We present the performance characteristics of the first quadrupole units (consisting of a lattice quadrupole magnet and correcting magnet mechanically and hydraulically coupled to a quadrupole). The main attention is paid to the field quality of the series of 6 quadrupoles measured by the same probe.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB383

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 01 September 2021

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TUPAB386

Design Study of the Nb₃Sn Cos-Theta Dipole Model for FCC-hh

2421

R.U. Valente
La Sapienza University of Rome, Rome, Italy
S. Burioli, P. Fabbricatore, S. Farinon, F. Levi, R. Musenich, A. Pampaloni
INFN Genova, Genova, Italy
E. De Matteis, M. Statera
INFN/LASA, Segrate (MI), Italy
F. Lackner, D. Tommasini
CERN, Meyrin, Switzerland
S. Mariotto, M. Prioli
INFN-Milano, Milano, Italy
M. Sorbi
Universita’ degli Studi di Milano & INFN, Segrate, Italy

In the context of the Future Circular Collider hadron-hadron (FCC-hh) R&D program, the Italian Institute of Nuclear Physics (INFN), in collaboration with CERN, is responsible for designing and constructing the Falcon Dipole (Future Accelerator post-LHC Costheta Optimized Nb₃Sn Dipole), which is an important step towards the construction of High Field Nb₃Sn magnets for a post LHC collider. The magnet is a short model with one aperture of 50 mm and the target bore field is 12 T (14 T ’ultimate’ field). The dipole is pre-loaded with the Bladder&Key technique to minimize the stress on the coils at room temperature, which are prone to degradation because of the Nb₃Sn cable strain-sensitivity. The electro-mechanical 2D design is focused on the performance, the field quality and the quench protection, with emphasis to the stresses on the the conductor. The Falcon Dipole has been modelled in a 3D FEM to determine the peak field distribution and the influence of the coil ends on the field quality.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB386

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 19 August 2021

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TUPAB387

Superconducting Solenoid Field Measurement and Optimization

2425

S. Ma, A. Arnold, P. Murcek, A.A. Ryzhov, J. Schaber, J. Teichert, R. Xiang, P.Z. Zwartek
HZDR, Dresden, Germany
H.J. Qian
DESY Zeuthen, Zeuthen, Germany

The solenoid is a significant part of an electron injector to provide a proper focusing, and preserve the beam projected emittance. A superconducting solenoid is applied for the SRF photoinjector at HZDR. The solenoid itself can degrade electron beam quality due to magnetic field imperfections like multipole components. In order to determine the field aberrations in the solenoid, we measured the superconducting solenoid magnetic field in the cryomodule. A simple and effective method is used to analyze the multipole field components, which will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB387

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 20 August 2021

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TUPAB388

Efficiency, Power Loss, and Power Factor Measurement of Quadrupole Magnet Power Supplies at the Spallation Neutron Source

2428

S. Harave
ORNL, Oak Ridge, Tennessee, USA
B. Morris
SLAC, Menlo Park, California, USA

The linear accelerator (LINAC) quadrupole magnets are powered by 42 silicon-controlled rectifier (SCR) based power supplies at the Spallation Neutron Source (SNS) facility of Oak Ridge National Laboratory. These 35V, 525A power supplies are bulky, inefficient and require both air and water cooling. The reliability of the SNS facility is impacted due to water leaks internal to power supplies and current readback issues associated with their unique control system interface, resulting in multiple downtime events. Hence, an alternate solution is necessary for the continued reliable operation of the SNS. To mitigate the above-mentioned problems, this paper proposes the use of off-the-shelf Switch Mode Power Supplies (SMPS) rated for 20V, 500A with serial control interface. These SMPS are air-cooled, more efficient and more compact owing to their switching speeds of approximately 160 kHz. The performance enhancements of the SMPS in comparison with the existing SCR power supply are discussed in detail in this paper. The features of the SMPS, along with experimental results for both power supplies, like efficiency, power losses and stability, are presented. Ongoing work is also discussed.

Poster TUPAB388 [0.420 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB388

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 17 August 2021

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TUPAB389

High Precision Four Quadrant Converter with GaN Technology

2431

M. Incurvati, T. Margreiterpresenter, R. Stärz
MCI, Innsbruck, Austria
T. Riedler
NTUT, Taipei City, Taiwan

New proton therapy facilities for the cure of tumors as well as high-energy photon sources are currently being installed all around the world. In this field, the request for special power supplies for corrector, scanning, and quadrupole magnets are increasing. For these applications, mandatory requirements are high bandwidth and current stability as well as low output ripple which are conflicting constraints. A feasibility study, prototype development, measurements, and investigations on the control methodology of a wide-bandgap GaN semiconductor-based power module is presented in the paper. The developed power module features the following characteristics: Eurocard standard PCB, bipolar 4Q operation, minimum switching frequency 100 kHz, bandwidth 5 kHz, output voltage and current up to 200 V / 8 A, output current ripple <20 ppm. The enlisted characteristics make it suitable for high inductive loads requiring fast transients (scanning magnets). An RST controller will be developed and a system identification approach to the transfer function of two parallel-connected power modules will be presented along with simulations assessing the performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB389

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paper received ※ 19 May 2021 paper accepted ※ 25 June 2021 issue date ※ 21 August 2021

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TUPAB391

Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18

2435

S. Aumüller, L.H.J. Bozyk, P.J. Spiller
GSI, Darmstadt, Germany
K. Blaum
MPI-K, Heidelberg, Germany

The FAIR complex at the GSI Helmholtzzentrum will generate heavy ion beams of ultimate intensities. To achieve this goal, medium charge states have to be used. However, the probability for charge exchange in collisions with residual gas particles of such ions is much higher than for higher charge states. In order to lower the residual gas density to extreme high vacuum conditions, 65% of the circumference of SIS18 are already coated with NEG, which provides high and distributed pumping speed. Nevertheless, nobel and nobel-like components, which have very high ionization cross sections, do not get pumped by this coating. A cryogenic environment at moderate temperatures, i.e. at 50-80K, provides high pumping speed for all heavy residual gas particles. The only typical residual gas species, that cannot be pumped at this temperature is hydrogen. With an additional NEG coating the pumping will be optimized for all residual gas particles. The installation of cryogenic surfaces in the existing room temperature synchrotron SIS18 at GSI has been investigated. A prototype quadrupole chamber with cryogenic surfaces, first measurements, and simulations of the adapted accelerator are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB391

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paper received ※ 19 May 2021 paper accepted ※ 31 August 2021 issue date ※ 25 August 2021

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TUPAB392

Conceptual Design of the Vacuum System for the Future Circular Collider FCC-ee Main Rings

2438

R. Kersevan, C. Garion
CERN, Geneva, Switzerland

The Future Circular Collider study program comprises several machine concepts for the future of high-energy particle physics. Among them there is a twin-ring e⁻e⁺ collider capable to run at beam energies between 45.6 and 182.5 GeV, i.e. the energies corresponding to the resonances of the Z, W, H bosons and the top quark. The conceptual design of the two 100-km rings has advanced to what is believed to be a working solution, i.e. capability to deal with low-energy (45.6 GeV) high-current (1390 mA) version as well as the high-energy (182.5 GeV) low-current (5.4 mA) one, with intermediate energy and current steps for the other 2 resonances. The limit for all of the versions is given by the 50 MW/beam allotted to the synchrotron radiation (SR) losses. The paper will outline the main beam/machine parameters, the vacuum requirements, and the choices made concerning the vacuum chamber geometry, material, surface treatments, pumping system, and the related pressure profiles. The location of lumped SR photon absorbers for the generic arc cell has been determined. An outline of the studies needed and envisaged for the near future will also be given.

Poster TUPAB392 [3.036 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB392

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 25 August 2021

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TUPAB393

Study of Remote Helium Mass Spectrometer Leak Detection in Accelerator

2441

H.Y. He, D.H. Zhu
IHEP CSNS, Guangdong Province, People’s Republic of China
J.M. Liupresenter
DNSC, Dongguan, People’s Republic of China

In order to solve the problem that the vacuum system of the accelerator can’t be close to the operation for a long time, a long-distance helium mass spectrometer leak detection system is explored by studying the structure of the conventional round tube vacuum box of the vacuum system, which integrates the online vacuum leak detection, defect diagnosis and process design, improves the digital operation, realizes the accurate and effective detection of the leak location range and leak rate, and provides the technology for the remote leak detection of the vacuum system. Support.

Poster TUPAB393 [0.666 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB393

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paper received ※ 13 May 2021 paper accepted ※ 31 May 2021 issue date ※ 10 August 2021

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TUPAB395

Vacuum System Models for Minerva Linac Design

2443

S. Rey, M.A. Baylac, F. Bouly, E. Froidefond
LPSC, Grenoble Cedex, France
F. Davin, D. Vandeplassche
SCK•CEN, Mol, Belgium
L. Perrot, H. Saugnac
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100 MW Accelerator Driven System (ADS) by building a new flexible irradiation complex at Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton current of 4 mA in continuous wave operation, with an additional requirement for exceptional reliability. Supported by SCK•CEN and the Belgian federal government the project has entered in its phase I: this includes the development and the construction of the linac first part, up to 100 MeV. We here review the MINERVA linac vacuum system modelling studies that enabled to validate the choice of materials and vacuum equipment. The strengths and weaknesses of the vacuum design, highlighted by the models, will be discussed as well as the required improvements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB395

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paper received ※ 19 May 2021 paper accepted ※ 01 June 2021 issue date ※ 28 August 2021

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TUPAB396

The Thermal Outgassing Rate of Materials Used in Vacuum Systems

2447

A.M. Semenov
BINP & NSTU, Novosibirsk, Russia
A. Burdakov, A.A. Krasnov, B.P. Tolochko, A.V. Varand
BINP SB RAS, Novosibirsk, Russia
S.R. Ivanova
GPI, Moscow, Russia
A.A. Krasnov
NSU, Novosibirsk, Russia
M.A. Mikhailenko
ISSCM SB RAS, Novosibirsk, Russia
A.A. Shoshin
Budker INP & NSU, Novosibirsk, Russia

There are many rarely used materials in vacuum systems that are poorly investigated in terms of vacuum properties. For example, phosphors, scintillating materials, ferrites, various adhesives, etc. In addition, new organic materials are being developed with mechanical properties similar to those of conventional steel. The use of such materials is very promising in vacuum technology. This article presents the thermal degassing performance of several rarely used materials and promising materials for vacuum applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB396

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paper received ※ 18 May 2021 paper accepted ※ 31 August 2021 issue date ※ 20 August 2021

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TUPAB398

Vacuum Issues with Argon Gas in the LANSCE Accelerator

2450

T. Tajima, J.E. Bernal, D.A. Byers, J.P. Chamberlin, P. Pizzol, A. Poudel, K.A. Stephens
LANL, Los Alamos, New Mexico, USA

Funding: US DOE NNSA
In the Los Alamos Neutron Science Center (LANSCE) accelerator, there are about 220 500-L/s ion pumps running all the time. The oldest pumps recorded in the current system were installed in 1983. All the ion pumps are diode type ion pumps. In 2017, we started to suffer from ion pumps trips in an accelerator module 15 (M15) that includes 3 500-L/s ion pumps and they caused beam down times of the accelerator during the production run cycles. This paper reports the details of these trips, how we found it was argon gas that was causing the trips and how we tried to reduce it.

Poster TUPAB398 [0.817 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB398

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paper received ※ 19 May 2021 paper accepted ※ 01 June 2021 issue date ※ 28 August 2021

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TUPAB399

RF Characterisation of New Coatings for Future Circular Collider Beam Screens

2453

P. Krkotić, F. Pérez, M. Pont, N.D. Tagdulang
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
S. Calatroni
CERN, Meyrin, Switzerland
X. Granados, J. Gutierrez, T. Puig, A. Romanov, G.T. Telles
ICMAB, Bellatera, Spain
A.N. Hannah, O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.M. O’Callaghan Castella
Universitat Politécnica de Catalunya, Barcelona, Spain
D. Whitehead
The University of Manchester, Laser Processing Research Center, Manchester, United Kingdom

For the future high energy colliders being under the design at this moment, the choice of a low surface impedance beam screen coating material has become of fundamental importance to ensure sufficiently low beam impedance and consequently guaranteed stable operation at high currents. We have studied the use of high-temperature superconducting coated conductors as possible coating materials for the beam screen of the FCC-hh. In addition, amorphous carbon coating and laser-based surface treatment techniques are effective surface treatments to lower the secondary electron yield and minimise the electron cloud build-up. We have developed and adapted different experimental setups based on resonating structures at frequencies below 10 GHz to study the response of these coatings and their modified surfaces under the influence of RF fields and DC magnetic fields up to 9 T. Taking the FCC-hh as a reference, we will show that the surface resistance for REBCO-CCs is much lower than that of Cu. Further we show that the additional surface modifications can be optimised to minimise their impact on the surface impedance. Results from selected coatings will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB399

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paper received ※ 19 May 2021 paper accepted ※ 25 June 2021 issue date ※ 02 September 2021

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TUPAB400

Manufacturing of Ceramic Vacuum Chambers for Sirius On-Axis Kicker

2457

R. Defavari, O.R. Bagnato, M.W.A. Feitosa, F.R. Francisco, D.Y. Kakizaki, R.L. Parise, R.D. Ribeiro
LNLS, Campinas, Brazil

Ceramic vacuum chambers were produced by LNLS for the Sirius kickers. Alumina tubes with an elliptical inner shape of 9.5 mm (V) x 29 mm (H) and 500 mm long were successfully manufactured by a Brazilian company. Metallic F136 titanium flanges were brazed to Nb inserts using Ag-58.5Cu-31.5Pd wt% alloy, these inserts were brazed to the ceramic using Ag-26.7Cu-4.5Ti wt% active filler metal. A titanium film was coated inside the chamber using argon plasma by RF Magnetron Sputtering technique. Samples have been investigated by Scanning Electron Microscopy (SEM) to measure film thickness along the inner section of the tube, coating morphology, chemical composition and homogeneity. The total electrical resistance of the tube was also monitored during the sputtering process to achieve the desired value (0.2 ohms/square). In this contribution, we present the results of an On-Axis kicker manufacturing process developed by LNLS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB400

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 29 August 2021

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TUPAB401

Mechanical Design, Fabrication and Characterization of Electron Beam Position Monitors for Sirius

2461

R. Defavari, O.R. Bagnato, M.W.A. Feitosa, F.R. Francisco, G.R. Gomes, D.Y. Kakizaki, R.L. Parise, R.D. Ribeiro
LNLS, Campinas, Brazil

Beam Position Monitors were designed and manufactured to meet Sirius operation requirements. Final dimensional accuracy and stability of the BPM were achieved by careful specification of its components’ manufacturing tolerances and materials. AISI-305 Stainless Steel was used for the BPM support fabrication due to magnetic and thermal expansion constraints. High purity molybdenum for the electrode pin and Ti6Al4V F136 G23 alloy for housing was used to manufacture the sensor components for their thermal characteristics. The electrical insulator was made of high alumina. The materials were joined by an active metal brazing process using 0,01mm accurate fixtures. The brazed sensors were subjected to dimensional, mechanical, and metallurgical testing, as well as leak detection and optical microscopy inspection at each stage. The sensors were joined in Ti6Al4V F136 BPM bodies using TIG welding. Dimensional sorting was used to choose groups of sensors-to-body, and body-to-support pairs during the final assembly. 160 BPMs are currently in operation on Sirius storage ring. In this contribution, we present the results of BPM manufacturing and testing processes developed for Sirius.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB401

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 29 August 2021

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TUPAB402

Review of Technologies for Ion Therapy Accelerators

2465

H.X.Q. Norman, R.B. Appleby, A.F. Steinbergpresenter
UMAN, Manchester, United Kingdom
E. Benedetto
TERA, Novara, Italy
E. Benedetto, M. Sapinski
CERN, Meyrin, Switzerland
H.L. Owen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.L. Owen
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Sapinski
GSI, Darmstadt, Germany
S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

Cancer therapy using protons and heavier ions such as carbon has demonstrated advantages over other radiotherapy treatments. To bring about the next generation of clinical facilities, the requirements are likely to reduce the footprint, obtain beam intensities above 1E10 particles per spill, and achieve faster extraction for more rapid, flexible treatment. This review follows the technical development of ion therapy, discussing how machine parameters have evolved, as well as trends emerging in technologies for novel treatments such as FLASH. To conclude, the future prospects of ion therapy accelerators are evaluated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB402

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 24 August 2021

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TUPAB404

Monte Carlo Studies for Shielding Design for High Energy Linac for Medical Isotope Generation

2469

N. Upadhyay, S. Chacko
University of Mumbai, Mumbai, India
A.P. Deshpandepresenter, T.S. Dixit, P.S. Jadhav, R. Krishnan
SAMEER, Mumbai, India

The widely used radioactive tracer Technetium-99m (99mTc) is traditionally produced from Uranium via 235U (n, f) 99Mo reactions which depends heavily on nuclear reactors. Design studies for an alternative, cleaner approach for radioisotope generation using a high energy electron linac were initiated at SAMEER to generate 99Mo. The electron beam from a 30 MeV linac with an average current of 350 µA will be bombarded on a convertor target to produce X-rays which will be bombarded on enriched 100Mo target to produce 99Mo via (g, n) reaction. 99mTc will be eluted from 99Mo. The photons and neutrons produced in the process should be shielded appropriately to ensure radiation safety. This paper brings out the use of Monte Carlo techniques for photon and neutron shielding for our application. We used FLUKA to calculate the fluence, angular distribution and dose for photons and neutrons. Then, we introduced various layers of lead followed by HDPE, 5% borated HDPE and 40% boron rubber to ensure that the proposed shielding is sufficient to completely shield the photon as well as neutron radiation and hence is safe for operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB404

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 25 August 2021

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TUPAB405

Design of High Energy Linac for Generation of Isotopes for Medical Applications

2472

A.P. Deshpande, S.R. Bhat, T.S. Dixit, P.S. Jadhav, A.S. Kottawar, R. Krishnan, M.S. Kumbhare, J. Mishra, C.S. Nainwad, S.R. Name, R. Sandeep Kumar, A. Shaikh, K.A. Thakur, M.M. Vidwans, A. Waingankar
SAMEER, Mumbai, India
A.K. Mishra
INMAS, New Delhi, India
N. Upadhyay
University of Mumbai, Mumbai, India

Funding: Ministry of Electronics and Information Technology (MeitY), Govt. of India.
After successful implementation of 6 and 15 MeV electron linear accelerator (linac) technology for Cancer Therapy in India, we initiated the development of high energy high current accelerator for the production of radioisotopes for diagnostic applications. The accelerator will be of 30 MeV energy with 350 µA average current provided by a gridded gun. The linac is a side coupled standing wave accelerator operating at 2998 MHz frequency operating at p/2 mode. The choice of p/2 operating mode is particularly suitable for this case where the repetition rate will be around 400 Hz. Klystron with 7 MW peak power and 36 kW average power will be used as the RF source. The modulator will be a solid-state modulator. The control system is FPGA based setup developed in-house at SAMEER. A retractable target with tungsten will be used as a converter to generate X-rays via bremsstrahlung. The x-rays will then interact with enriched 100Mo target to produce 99Mo via (g, n) reaction. Eluted 99mTc will be used for diagnostic applications. The paper lists the challenges and novel schemes developed at SAMEER to make a compact, rugged, and easy to use system keeping in mind local conditions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB405

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 02 September 2021

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TUPAB406

Search for New Isotope Production Pathways

2475

L.F. Dabill
Coe College, Cedar Rapids, Iowa, USA
A. Hutton
JLab, Newport News, Virginia, USA

The isotope group at Jefferson Lab is carrying out R&D for producing medically interesting radioisotopes, especially those with theranostic (therapeutic and diagnostic) attributes. Here the search for viable production mechanisms has been expanded to multi-step reactions where a daughter is produced from the target and decays into a medically interesting granddaughter radioisotope. It is difficult to find efficient production routes when investigating both the initial excitation reaction as well as the decay routes leading to medically interesting isotopes. The overall goal of this project is to create a structured code in Python to find these decay routes by automatically exploring the large number of isotopes and their possible decay modes. The program structure is described, and preliminary results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB406

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 14 August 2021

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TUPAB407

A Novel Beam Optics Concept to Maximize the Transmission Through Cyclotron-based Proton Therapy Gantries

2477

V. Maradia, A.C. Giovannelli, A.L. Lomax, D. Meer, S. Psoroulas, J.M. Schippers, D.C. Weber
PSI, Villigen PSI, Switzerland
V. Maradia
ETH, Zurich, Switzerland
D.C. Weber
University of Zurich, University Hospital, Zurich, Switzerland
D.C. Weber
KRO, Bern, Switzerland

Funding: This work is funded by a PSI inter-departmental funding initiative (CROSS).
Most of the conventional beam optics of cyclotron-based proton gantries were designed to provide point-to-point focus in both planes with an imaging factor between 1 and 2 from the entrance of the gantry to the patient. This means that a small beam size at the gantry entrance is required to achieve the required small beam size at the patient. Due to the typically used beam emittance, this in turn results in large beam divergence at the gantry entrance, increasing the possibility of beam losses along the gantry as the beam envelope gets close to the apertures. To maximize transmission through the gantry, we propose a novel beam optics concept using 3:1 imaging. It reduces the beam divergence at the gantry entrance by factor 3 while still achieving a small beam size at the patient. The beam envelope is better controlled and keeps clear of the apertures compared to the 1:1 or 1:2 imaging beam envelope. For PSI Gantry 2, the novel 3:1 imaging beam optics increase the proton beam transmission for lower energies by 40% compare to 1:1 imaging beam optics. The usage of small imaging factors can help to maximize transmission for different gantry lattices, thus reducing treatment times.

Poster TUPAB407 [1.347 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB407

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paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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TUPAB408

A Novel Automatic Focusing System for the Production of Radioisotopes for Theranostics

2480

P. Häffner, C. Belver-Aguilar, S. Braccini, P. Casolaro, G. Dellepiane, I. Mateu, P. Scampoli, M. Schmid
AEC, Bern, Switzerland
P. Scampoli
Naples University Federico II, Napoli, Italy

Funding: This research was partially funded by the Swiss National Science Foundation (SNSF). Grants:200021₁75749, CRSII5₁80352, CR23I2₁56852.
A research program on the production of novel radioisotopes for theranostics is ongoing at the 18 MeV Bern medical cyclotron laboratory equipped with a solid target station. Targets are made of rare and expensive isotope enriched materials in form of compressed 6 mm diameter pellets. The irradiation of such a small target is challenging. A specific capsule has been developed made of two aluminum halves kept together by permanent magnets. Since the beam extracted from a medical cyclotron is about 12 mm FWHM, an automatic compact focusing system was conceived and constructed to optimise the irradiation procedure. It is based on a 0.5 m long magnetic system, embedding two quadrupoles and two steering magnets, and a non-destructive beam monitoring detector located in front of the target. The profiles measured by the detector are elaborated by a specific software that, through a feedback optimisation algorithm, acts on the magnets and keeps the beam focused on target. Being about 1 m long, it can be installed in any existing medical cyclotron facility. The design of the first prototype together with the results of the first beam tests are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB408

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paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 19 August 2021

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TUPAB409

FLUKA and Geant4 Monte Carlo Simulations of a Desktop, Flat Panel Source Array for 3D Medical Imaging

2483

T. Primidis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T. Primidis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
V. Soloviev
Adaptix Imaging, Didcot, United Kingdom

Funding: Funded by the Accelerators for Security, Healthcare and Environment CDT from the United Kingdom Research and Innovation Science and Technology Facilities Council, reference ID ST/R002142/1
Digital tomosynthesis (DT) is a 3D imaging modality with a lower cost and lower dose than computed tomography. A DT system made of a flat panel array with 45 X-ray sources, but compact enough to fit on the desktop is near market realisation by the company Adaptix Ltd. This work presents a framework of FLUKA and Geant4 Monte Carlo (MC) simulations of the Adaptix system including the X-ray beam generation and the final image quality. The results show that MC methods offer an insight into the performance details of such an innovative device at different levels between the X-ray emitter array and the detector. As such, a large portion of the design and optimisation of such novel X-ray imaging systems can be done with a single toolkit. Finally, the modularity of the approach allows other tools to be imported at various steps within the framework and thus provide answers to questions that cannot be addressed by general-purpose MC codes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB409

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 24 August 2021

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TUPAB410

Finite Element Analysis and Experimental Validation of Low-Pressure Beam Windows for XCET Detectors at CERN

2487

J. Buesa Orgaz, M. Brugger, G. Romagnoli, O. Sacristan De Frutos, F. Sanchez Galan
CERN, Meyrin, Switzerland

In the framework of the renovation and consolidation of experimental areas at CERN, a low-pressure design beam superimposed windows (250 µm Mylar and 150 µm polyethylene) for the Threshold Cherenkov counters (XCET) has been modelled and verified for its implementation. The XCET is a detector used to count the number of selected charged particles in the beam by adjusting the pressure that leads to the emission of Cherenkov photons only above certain pressure threshold. Simultaneously, the charged particles pass from a vacuum environment to the pressurized refractive gas vessel through a solid interface. Minimal material in this solid interface is therefore crucial to avoid interactions of the low-energy particles which may lead to beam intensity loss or background production. Hence, thin and low-density materials are required to mitigate multiple scattering and energy loss of the incoming particles while still allowing the needed pressures inside the counter vessel. A XCET validation methodology was conducted using Finite Element Analysis (FEA), followed by experimental validations performing burst pressure tests and using Digital Image Correlation (DIC).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB410

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 24 August 2021

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TUPAB412

New 3 MeV and 7 MeV Accelerators for Cargo Screening and NDT

2491

S. Proskin, D. Fischer, A.V. Mishin
Varex Imaging, Salt Lake City, USA

For decades evaluating of cargo and non-destructive testing of objects have been utilizing high energy systems based on particle accelerators. End users wish for lower prices, better image quality, and convenience of utilization. In recent years Varex Imaging, world leader in innovation, development, and manufacture of X-ray imaging component solutions, has been developing a series of new accelerator products with improved parameters and a goal of replacing existing dated systems and growing of emerging markets. New S-band energy regulated 3 MeV and 7 MeV linear accelerators have been designed, tested at Varex Imaging and their customer sites. Novel linacs benefit is in dramatically increased output, reduced beam spot, longer operation, and improved versatility. Authors will outline recent progress and future endeavors in linear accelerator development with regards to improvement of accelerating structures, X-ray targets, and corresponding RF components*.
This work would have not been successful without outstanding contribution of the whole Linac Group of Varex Imaging and established partnerships with our customers

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB412

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 18 August 2021

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TUPAB413

Rapid Browser-Based Visualization of Large Neutron Scattering Datasets

2494

D.L. Bruhwiler, K. Bruhwilerpresenter, P. Moeller, R. Nagler
RadiaSoft LLC, Boulder, Colorado, USA
C.M. Hoffmann, Z.J. Morgan, A.T. Savici, M.G. Tucker
ORNL, Oak Ridge, Tennessee, USA
A. Kuhn, J. Mensmann, P. Messmer, M. Nienhaus, S. Roemer, D. Tatulea
NVIDIA, Santa Clara, USA

Funding: This work is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0021551.
Neutron scattering makes invaluable contributions to the physical, chemical, and nanostructured materials sciences. Single crystal diffraction experiments collect volumetric scattering data sets representing the internal structure relations by combining datasets of many individual settings at different orientations, times and sample environment conditions. In particular, we consider data from the single-crystal diffraction experiments at ORNL.* A new technical approach for rapid, interactive visualization of remote neutron data is being explored. The NVIDIA IndeX 3D volumetric visualization framework** is being used via the HTML5 client viewer from NVIDIA, the ParaView plugin***, and new Jupyter notebooks, which will be released to the community with an open source license.
* L. Coates et al., Rev. Sci. Instrum. 89, 092802 (2018).
** https://developer.nvidia.com/nvidia-index
*** https://blog.kitware.com/nvidia-index-plugin-in-paraview-5-5

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB413

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paper received ※ 18 May 2021 paper accepted ※ 21 July 2021 issue date ※ 26 August 2021

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TUPAB415

Irradiation Methods and Infrastructure Concepts of New Beam Lines for NICA Applied Research

2498

G.A. Filatov, A. Agapov, A.V. Butenko, K.N. Shipulin, A. Slivin, E. Syresin, A. Tuzikov, A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia
S. Antoine, W. Beeckman, X.G. Duveau, J. Guerra-Phillips, P.J. Jehanno
SIGMAPHI S.A., Vannes, France

Nowadays space exploration has faced the issue of radiation risk to microelectronics and biological objects. The new beamlines and irradiation stations of the Nuclotron-based Ion Collider fAcility (NICA) at JINR are currently under construction to study this issue. The beamline parameters, different methods for homogeneous irradiation of targets such as scanning, and beam profile shaping by octupole magnets are discussed. A short description of the building infrastructure, magnet elements, and detectors for these beamlines is also given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB415

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paper received ※ 11 May 2021 paper accepted ※ 02 June 2021 issue date ※ 13 August 2021

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TUPAB416

Depth-Dose Distribution Dependence on the Energy Profile of Linear and Laser Wakefield Accelerator Electron Beams

2502

T.A. Nguyen
VNUHCM, Ho Chi Minh, Viet Nam
C. Rangacharyulu
University of Saskatchewan, Saskatoon, Canada
C.V. Tao
HCMUS, Ho Chi Minh City, Viet Nam

The depth-dose distributions of 10 MeV electron beams used for food irradiation and sterilization purposes at Research and Development Center for Radiation Technology, HCMC, Vietnam are measured and the results are well reproduced by the MCNP simulations. We extend the simulations to predict the dose depth distribution for 10 MeV electron beams with the energy profiles of a model Laser Wake Field accelerator (LWFA). The dosimetry and simulation results show that the maximum dose of the depth-dose curve inside the product is 1.4 times surface dose with an area density limit of 8.6 g/cm² for two-sided irradiation with nearly mono-energetic beams from the linear accelerator and the corresponding parameters for LWFA are 1.2 times surface dose and 13.0 g/cm², respectively.

Poster TUPAB416 [1.506 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB416

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paper received ※ 17 May 2021 paper accepted ※ 11 June 2021 issue date ※ 31 August 2021

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TUPAB417

Pushing Spatial Resolution Limits In Single-Shot Time-Resolved Transmission Electron Microscopy at the UCLA Pegasus Laboratory

2506

P.E. Denham, P. Musumeci
UCLA, Los Angeles, USA

Funding: This work was supported by DOESTTR grant No. DE-SC0013115 and by by the National Science Foundation under STROBE Science and Technology Center Grant No. DMR-1548924
We present the design of a high-speed single shot relativistic electron microscope planned for implementation at the UCLA PEGASUS Laboratory capable of imaging with less than 30~nm spatial resolution and image acquisition time on the order of 10~ps. This work is based on a multi-cavity acceleration scheme for producing relativistic beams (3.75 MeV) with suppressed rms energy spread (σ_δ ≈5e-5), and a means to reduce smooth space charge aberrations by generating a quasi-optimal 4D particle distribution at the sample plane. start-to-end simulation results are used to validate the entire setup. Ultimately, a feasible working point is demonstrated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB417

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 01 September 2021

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