IPAC2019 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOZZPLS2	Positron Driven Muon Source for a Muon Collider: Recent Developments	target, damping, collider, positron	49
	M.E. Biagini, M. Antonelli, O.R. Blanco-García, M. Boscolo, A. Ciarma, A. Giribono, S. Guiducci, C. Vaccarezza, A. Variola INFN/LNF, Frascati, Italy A. Bacci INFN-Milano, Milano, Italy M. Bauce, F. Collamati INFN-Roma1, Rome, Italy G. Cesarini INFN-Roma, Roma, Italy I. Chaikovska, R. Chehab LAL, Orsay, France S.M. Liuzzo, P. Raimondi ESRF, Grenoble, France D. Lucchesi Univ. degli Studi di Padova, Padova, Italy N. Pastrone INFN-Torino, Torino, Italy
	The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related to muon production, cooling, accumulation and acceleration. The Low Emittance Muon Accelerator (LEMMA) concept ,* presents in this paper an upgraded layout of a positron driven muon source. The positron beam, stored in a ring with high energy acceptance and low emittance, is extracted and driven in a push-pull configuration to a multi-target system, to produce muon pairs at threshold on the target’s electrons. This solution alleviates the issues related to the power deposited and the integrated Peak Energy Density Deposition on the targets. Muons produced in the multi-target system will then be accumulated in many parallel rings before acceleration and injection in the collider. A special multi-target line lattice has been designed to cope with the focusing of both the positron and muon beams. Studies on the number, material and thickness of the targets have been carried out. A general layout of the overall scheme and a description is presented, as well as plans for future R&D. * M. Antonelli, P. Raimondi, INFN-13-22/LNF, 2013 ** M. Boscolo, M. Antonelli, O.R. Blanco-Garcia, S. Guiducci, S. Liuzzo, P. Raimondi, F. Collamati, Phys. Rev. Accel. Beams, vol. 21, p. 061005, 2018
	Slides MOZZPLS2 [4.360 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLS2
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW015	Notes on Linear Theory of Coupled Particle Beams with Equal Eigenemittances	betatron, linear-dynamics, synchrotron	98
	V. Balandin, N. Golubeva DESY, Hamburg, Germany
	We consider some aspects of the linear theory of coupled particle beams with equal eigenemittances and compare them with the one dimensional Courant-Snyder theory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW015
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPGW019	Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee	lattice, simulation, optics, coupling	112
	D. El Khechen, K. Oide, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW019
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW020	Numerical Calculation of Micro Bunching in BERLinPro Due to Space Charge and CSR Effects	bunching, space-charge, linac, optics	116
	B.C. Kuske, A. Meseck HZB, Berlin, Germany
	Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association BERLinPro is an Energy Recovery Linac Project, currently being set up at the Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany. BERLinPro is a small demonstrator for ERL technology and applications. Due to the low energy of 50, resp. 32MeV, space charge plays a dominant role in the beam dynamics. Micro-bunching, due to unavoidable shot noise from the cathode in combination with space charge, is seen in the merger as well as in the recirculator. Coherent synchrotron radiation (CSR) can amplify this bunching, as well as micro-bunching can enhance CSR losses. With the release of OPAL 2.0** in May 2018, for the first time, an open source, highly parallel tracking code is available, that is capable of numerically calculating both effects, space charge and CSR, simultaneously. The calculations are compared to earlier results, that used analytical formulas on tracked, space charge dominated bunches. "On space charge driven microbunching instability in BERLinPro", PhD thesis, S.D.Rädel, Humboldt Universität zu Berlin, 2017 ** http://amas.web.psi.ch/docs/opal/opal_user_guide-2.0.0.pdf
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW020
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW022	Achromatic Isochronous Mode of the ESR at GSI	optics, sextupole, experiment, detector	124
	S.A. Litvinov, M. Steck GSI, Darmstadt, Germany
	The isochronous optics of the ESR is a unique ion-optical setting in which the ring is operated as a Time-of-Flight Mass-Spectrometer and is used for direct mass measurements of short-lived exotic nuclei. The present isochronous optics had been performed only making a negative dispersion in the straight sections of the ESR of about -7 m. This negative dispersion makes the injection into the ESR very complicated and strict the transmission of the ions in the ring. Moreover, the non-achromatism of the ESR brings a supplementary uncorrectable first-order transverse contribution to the revolution time. In order to make the ESR achromatic, to improve injection and the isochronicity a new achromatic isochronous optics has been calculated and will be presented here in details.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW022
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW024	Measurements of the GSI Transfer Beam Lines Ion Optics	quadrupole, extraction, experiment, storage-ring	131
	M. Sapinski, O. Geithner, S. Reimann, P. Schütt, M. Vossberg, B. Walasek-Höhne GSI, Darmstadt, Germany C. Heßler CERN, Meyrin, Switzerland
	GSI High Energy Beam Transfer lines (HEST) link the SIS18 synchrotron with two storage rings (Experimental Storage Ring and Cryring) and six experimental caves. The recent upgrades to HEST beam instrumentation enables precise measurements of beam properties along the lines and allow for faster and more precise beams setup on targets. Preliminary results of some of the measurements performed during runs in 2018 and 2019 are presented here. The focus is on response matrix measurements and quadrupole scans performed on HADES beam line. The errors and future improvements are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW024
About •	paper received ※ 15 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW028	Study for the Alignment of Focusing Solenoid of ARES RF Gun and Effect of Misalignment of Solenoid on Emittance of Space Charge Dominated Electron Beam	solenoid, alignment, electron, gun	147
	S. Yamin, R.W. Aßmann, B. Marchetti DESY, Hamburg, Germany
	SINBAD (Short and INnovative Bunches and Accelerators at DESY) facility will host multiple experiments relating to ultra-short high brightness beams and novel experiments with ultra-high gradient. ARES (Accelerator Research Experiment at SINBAD) Linac is an S-band photo injector to produce such electron bunches at around 100 MeV. The Linac will be commissioned in stages with the first stage corresponding to gun commissioning. In this paper, we present studies about the scheme adopted for the alignment of focusing solenoid for the ARES gun. The method is bench marked using ASTRA simulations. Moreover the effect of misalignment of the solenoid on the emittance of space charge dominated scheme and its compensation is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW028
About •	paper received ※ 26 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW037	Dynamic Variation of Chromaticity for Beam Instability Mitigation in the 3-GeV RCS of J-PARC	simulation, extraction, injection, impedance	171
	P.K. Saha, H. Harada, H. Hotchi, Y. Shobuda, T. Takayanagi, F. Tamura, Y. Watanabe JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We have studied many other dynamic approaches from that reported in the IPAC 2018 for transverse beam instability mitigation in the presence of strong space charge in the 3-GeV RCS of J-PARC. One of such a method is the introduction of an excess of chromaticity from that of natural chromaticity by reversing the sextupole magnetic fields from the middle of the acceleration cycle. The benifits of this method are twofold. It allows to utilize sextupole for chromaticty correction at lower energy and also mitigate the beam instability at higher energy because of introducing higher chromaticity. We first carried out numerical simulations by using ORBIT code, experimentally verified and then applied for the machine operation. The detail of simulation and measurements results are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW037
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW038	Collimator’s Impact Into the Transverse Emittance Growth at KEK Compact ERL	wakefield, simulation, operation, FEL	174
	O.A. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, Y. Tanimoto KEK, Ibaraki, Japan
	In high-intensity particle accelerators, unwanted trans-verse and longitudinal wakefields arise when the high-charge particle beam passes through the narrow chambers or locations with small transverse apertures, such as collimator jaws. Transverse wakefields impose a transverse kicks to the beam, changing its shape, and leading to the growth of the transverse emittance. Longitudinal wakes cause the beam energy losses, heating of the narrow chambers etc. In the present study we investigated the collimator’s impact to the beam. Thus, we evaluated the collimator’s wakefields through the CST simulations. We estimated the corresponding transverse kicks and longitudinal wakes. In the summary simulation results were cross-checked with correspondent analytical expressions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW038
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPGW040	Beam Optics Design of the Superconducting Region of the JAEA ADS	linac, cavity, controls, lattice	181
	B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW040
About •	paper received ※ 17 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW048	Design Study of an Electron Storage Ring for the Future Plan of Hiroshima Synchrotron Radiation Center.	storage-ring, synchrotron, radiation, synchrotron-radiation	200
	S. Matsuba, M. Katoh, K.S. Shimada HSRC, Higashi-Hiroshima, Japan K. Harada KEK, Ibaraki, Japan K. Kawase QST, Tokai, Japan
	Hiroshima synchrotron radiation center equips a 700 MeV electron storage ring nicknamed HiSOR. It has been operated for more than 20 years. The emittance of HiSOR is 400 nm, which is larger by one or more orders of magnitude than typical modern synchrotron light sources. Therefore, as the future plan of the facility, a new low emittance storage ring is desired. Several designs have been examined. In the newest version, we have selected the lattice structure similar to ASTRID 2 compact light source in Aarhus University, Denmark. The design goal is the energy of around 500 MeV, the circumference shorter than 50 m and the emittance smaller than 10 nm with straight sections for undulators more than 4. In this conference, we report the latest result from the design study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW048
About •	paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW054	Study on Spherical Aberration Correction of Solenoid Lens in Ultrafast Electron Diffraction	electron, induction, solenoid, focusing	213
	Y.T. Yang, K. Fan, J.J. Li HUST, Wuhan, People’s Republic of China Y. Song Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
	High electron beam quality is required in Ultrafast Electron Diffraction (UED) to achieve high spatial resolution. However, aberrations mainly induced by solenoid lens will deteriorate the beam quality and limit the resolution. Spherical aberration introduces the largest distortion which is unavoidable in the case of static cylindrically symmetric electromagnetic fields on the basis of Scherzer’s theorem. In order to reduce the spherical aberrations, different models have been designed which are composed of three symmetrical lens and one asymmetrical lens. We obtain the magnetic field distribution and calculate the aberration of each model by OPERA, and the result is that the solenoid without poles has the minimum aberration and meets the design requirement best.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW054
About •	paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPGW070	Longitudinal Stability of the Hollow Ion Bunches After Momentum Slip-Stacking in the CERN SPS	simulation, damping, synchrotron, proton	254
	T. Argyropoulos, A. Lasheen, D. Quartullo, E.N. Shaposhnikova CERN, Geneva, Switzerland
	Momentum slip-stacking is planned to be used for the lead ion beams in the CERN SPS to double the beam intensity for the High-Luminosity LHC project. During this RF manipulation two SPS batches, controlled by two independent RF systems, are going to be interleaved on an intermediate energy plateau, reducing the bunch spacing from 100 to 50 ns. However, there are limitations how close the frequencies of two RF systems can approach each other, resulting in a hole in the longitudinal bunch particle distribution due to the offset in energy of the recaptured bunches. After filamentation, these bunches should be further accelerated to the SPS top energy, before extraction to the LHC. Macro-particle simulations have shown that Landau damping is lost for the bunches with the smallest longitudinal emittances in the batch, causing un-damped oscillations of the bunch core after recapture. The standard application of an additional, fourth harmonic RF system, successfully used in proton operation, was not able to damp the oscillations at top energy, while it was necessary to switch it on from the moment of recapture. In this paper the longitudinal stability of the bunches after slip-stacking is studied in more details both by macro-particle simulations and analytical calculations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW070
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPGW078	Change of Beam Distribution Due to Decoherence in the Presence of Transverse Feedback	feedback, simulation, octupole, damping	281
	S.V. Furuseth, X. Buffat CERN, Geneva, Switzerland S.V. Furuseth EPFL, Lausanne, Switzerland
	The effect of Landau damping is often calculated based on a Gaussian beam distribution in all degrees of freedom. The stability of the beam is however strongly dependent on the details of the distribution. The present study focuses on the change of bunch distributions caused by the decoherence of the excitation driven by an external source of noise, in the presence of both amplitude detuning and a transverse feedback. Both multiparticle tracking simulations and theoretical models show a similar change of the distribution. The possible loss of Landau damping driven by this change is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW078
About •	paper received ※ 08 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW083	Longitudinal Coupled-Bunch Instability Evaluation for FCC-hh	impedance, cavity, HOM, synchrotron	297
	I. Karpov, E.N. Shaposhnikova CERN, Meyrin, Switzerland
	High-order modes (HOM) of the accelerating rf structures and other machine elements, if not sufficiently damped, can drive longitudinal coupled-bunch instabilities (CBI). Their thresholds can be accurately obtained from macro-particle simulations using the detailed impedance model containing many different contributions. This method, however, is very difficult to apply for synchrotrons with a large number of bunches, as it is the case for the Future Circular hadron-hadron Collider (FCC-hh) with up to 10400 circulating bunches per beam. In this paper the semi-analytical approach is used for calculations of the instability thresholds during the acceleration cycle of the FCC-hh. As the result, we define requirements for the HOM damping that would be sufficient to prevent development of longitudinal CBI in the presence of weak synchrotron radiation damping.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW083
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW091	Capture and Flat-Bottom Losses in the CERN SPS	beam-loading, injection, impedance, feedback	327
	M. Schwarz, A. Lasheen, G. Papotti, J. Repond, E.N. Shaposhnikova, H. Timko CERN, Meyrin, Switzerland
	Particle losses on the flat bottom of the SPS, the last accelerator in the injector chain of the LHC at CERN, are a strong limitation for reaching the high intensities required by the high luminosity upgrade of the LHC. Two contributions to these losses are investigated in this paper. The first losses occur during the PS-to-SPS bunch-to-bucket transfer, since the bunch rotation in the PS creates halo particles and the bunch does not completely fit into the SPS RF-bucket. The effect of longitudinal shaving in the PS on the beam transmission was recently tested. At high intensities, further capture losses are caused by beam loading in the traveling wave RF system of the SPS, which is partially compensated by the LLRF system, in particular by one-turn delay feedback. While the feedforward system reduces the capture losses, it also increases the losses along the flat bottom due to the RF noise.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW091
About •	paper received ※ 09 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW092	Design Status of DESY IV – Booster Upgrade for PETRA IV	booster, injection, insertion, linac	331
	H.C. Chao DESY, Hamburg, Germany
	In PETRA IV project the on-axis injection scheme is preferred since there is no sufficient dynamic aperture for off-axis injection in ultra low emittance storage rings. The challenge is to prepare the injected bunches with the smaller emittance and larger intensity. The current injector complex including the accumulator and booster does not fulfill the requirements and thus will need refurbishments. The injector upgrade option chosen will be composed of an upgraded electron gun, a higher energy LINAC, and the new booster synchrotron DESY IV which has smaller emittance. DESY IV will be located in the existing tunnel of the current booster DESY II. The design of the lattice and some simulation results are addressed in this article.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW092
About •	paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW096	Beam Dynamics in MBA Lattices with Different Chromaticity Correction Schemes	lattice, sextupole, betatron, storage-ring	346
	L. Hoummi, J. Resta-López, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom L. Hoummi, J. Resta-López, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A. Loulergue, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	Ultra-low emittance lattices are being studied for the future upgrade of the 2.75 GeV SOLEIL storage ring. The candidate baseline lattice was inspired by the ESRF-EBS-type Multi-Bend-Achromat (MBA) lattice, introducing a (-I) transformation to compensate the nonlinear impact of sextupoles thanks to the lattice symmetry and tight control of the betatron phase advance between sextupoles. Whilst the final performance is still being optimized, other types of lattices are being considered for SOLEIL: This includes the so-called High-Order Achromat (HOA) lattice. Though the (-I) scheme provides a large on-momentum transverse dynamic aperture in 4D, its off-momentum performance is rather limited. 6D studies reveal intrinsic off-momentum transverse oscillations which are likely to result from a nonlinear increase in path length. This contribution presents the effects from the inhomogeneous sextupole distribution in the (-I) scheme and compares them with the HOA lattice.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW096
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW111	Start to End Simulation on Beam Dynamics in Coherent Electron Cooling Accelerator	electron, FEL, bunching, cavity	379
	Y.C. Jing, V. Litvinenko, I. Petrushina, I. Pinayev, K. Shih, Y.H. Wu BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA I. Petrushina SUNY SB, Stony Brook, New York, USA K. Shih SBU, Stony Brook, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A Coherent electron Cooling (CeC) has a potential of substantial reducing cooling time of the high-energy hadrons and hence to boost luminosity in high-intensity hadron-hadron and electron-hadron colliders. In a CeC system, a high quality electron beam is generated, propagated and optimized through a beam line which was carefully designed with consideration of space charge effect, wakefields and nonlinear dynamics such as coherent synchrotron radiation and chromatic aberration. In this paper, we present our study on the beam dynamics of such a beam line and compare the simulation result with what was measured in experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW111
About •	paper received ※ 17 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW112	Design of a Bunch Compressor with CSR Suppression to Achieve Hundreds of kA Peak Current	electron, optics, site, dipole	382
	Y.C. Jing, V. Litvinenko BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A four dipole magnetic chicane is usually used to compress electron bunch to very short in modern accelerators which requires electron beams to have high peak current. The coherent synchrotron radiation (CSR) originated from the strong bending magnets in the chicane could greatly degrade the quality of the electron beam. In this paper, we present our design for a bunch compressing system with 30 to 100 fold in bunch length reduction and at the mean time suppress the effect of CSR on the e-beam’s quality. We discuss and detail the performance of such a compressor for potential FACET-II upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW112
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW115	A Cross-Cell Interleaved Nonlinear Lattice for Potential NSLS-II Upgrade	lattice, sextupole, optics, dynamic-aperture	393
	Y. Li, A. He, B.N. Kosciuk, T.V. Shaftan, V.V. Smaluk BNL, Upton, Long Island, New York, USA Z.H. Bai, L. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	An interleaved sextupole scheme using cross-cell betatron phase cancellation technique is adopted as a candidate for the future NSLS-II upgrade lattice. The lattice uses as many NSLS-II installed magnets as possible, including 30 dipoles, to compose a triple bend achromat lattice. A 300 pm.rad horizontal beam emittance is achieved. The emittance can be further reduced to around 200 pm rad with damping wigglers. Various design concepts used in modern 4th-generation light sources, such as adopting longitudinal gradient dipoles and anti-bend scheme, are incorporated into the design as well. The betatron phase-advance between sextupoles is designed to have a cross-cell interleaving cancellation pattern in the transverse planes. The dynamic aperture is big enough for the conventional off-axis top-off injection. At the same time, a large energy acceptance looks promising to ensure a sufficiently long beam lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW115
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP002	Linac and Damping Ring Designs for the FCC-ee	linac, positron, gun, electron	420
	S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia I. Chaikovska, R. Chehab LAL, Orsay, France K. Furukawa, N. Iida, T. Kamitani, F. Miyahara, K. Oide KEK, Ibaraki, Japan E.V. Ozcan Bogazici University, Bebek / Istanbul, Turkey S.M. Polozov MEPhI, Moscow, Russia L. Rinolfi ESI, Archamps, France F. Yaman IZTECH, Izmir, Turkey
	We report the design of the pre-injector chain for the Future Circular e⁺ e⁻ Collider (FCC-ee) system. The electron beam from a low-emittance RF gun is accelerated by an S-band linac up to 6 GeV. A damping ring at 1.54 GeV is required for emittance cooling of the positron beam. The intermediate energy step from the exit of the S-band linac at 6 GeV to the 20 GeV injection energy of the top-up booster can be provided by the modified Super Proton Synchrotron (SPS), serving as a pre-booster ring (PBR). An alternative option to reach 20 GeV energy would be to extend the S-band linac with a C- or X-band linac. An overall cost optimisation will determine the choice of the final configuration. Beam loss and emittance dilution in the linac due to space charge effects, wakefields, and misalignment of accelerator components can be mitigated by RF phasing and orbit steering. Start-to-end simulations examine the beam transport through the linac up to either 6 GeV or 20 GeV. The results indicate large design margins. Simulations of the beam dynamics in the damping ring (DR) demonstrate a sufficiently large momentum acceptance. Effects of intrabeam scattering and electron cloud instability in the DR are also studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP002
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPMP009	Effect of Initial Parameters on the Super Flat Beam Generation with the Phase-Space Rotation for Linear Colliders	simulation, gun, collider, solenoid	442
	M. Kuriki, R. Tamura HU/AdSM, Higashi-Hiroshima, Japan H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan P. Piot Northern Illinois University, DeKalb, Illinois, USA J.G. Power ANL, Argonne, Illinois, USA K. Sakaue The University of Tokyo, The School of Engineering, Tokyo, Japan M. Washio RISE, Tokyo, Japan
	Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI) Kiban B. Linear collider is a concept to realize e⁺e⁻ collision beyond the limitation of the ring colliders by the synchrotron radiation. To obtain an enough luminosity, eg. 1.0·10⁺³⁴ cm^-2sec^-1, the beam is focused down to nano-meter size with a high aspect ratio. This super flat beam is useful to improve the luminosity and to compensate the beam-beam effect, eg. Beamstrahlung. In a conventional design, the super-flat beam is produced by radiation damping in a storage ring. We propose to produce this super-flat beam with phase-space rotation techniques. We employ both Round to Flat Beam Transformation and Transverse to Longitudinal Emittance eXchange, the super flat beam can be generated by controlling the space-charge effect which spoiled the performance. We present the RFBT performance with respect to the initial conditions, i.e. beam size, initial emittance, solenoid field (strength and profile), etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP009
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP016	Intra-Bunch Energy Spread Minimisation for CLIC Operation at a Centre-of-Mass Energy of 350 GeV	linac, luminosity, collider, linear-collider	458
	N. Blaskovic Kraljevic, D. Arominski, D. Schulte CERN, Meyrin, Switzerland
	The first stage of the electron-positron Compact Linear Collider (CLIC) is designed with a centre-of-mass energy of 380 GeV. A dedicated threshold scan in the vicinity of 350 GeV is envisioned with a total integrated luminosity of 100 fb^-1. This scan calls for a very small intra-bunch energy spread in order to achieve an excellent collision energy resolution. This paper presents an optimised assignment of RF accelerating gradients and phases in the CLIC main linac for operation at 350 GeV, which minimises the energy spread at the end of the main linac whilst preserving a small emittance growth. Variation of the bunch length and charge is studied in order to further reduce the energy spread; the effect on both the peak and total luminosity is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP016
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP017	Beam Orbit Correction in the CLIC Main Linac Using a Small Subset of Correctors	linac, quadrupole, collider, ground-motion	461
	N. Blaskovic Kraljevic, D. Schulte CERN, Meyrin, Switzerland
	Beam orbit correction in future linear colliders, such as the Compact Linear Collider (CLIC), is essential to mitigate the effect of accelerator element misalignment due to ground motion. The correction is performed using correctors distributed along the accelerator, based on the beam position monitor (BPM) readout from the preceding bunch train, with a train repetition frequency of 50 Hz. This paper presents the use of the MICADO algorithm* to select a subset of N ~ 10 correctors (from a total of 576) to be used for orbit correction in the designed 380 GeV centre-of-mass energy first-stage of CLIC. The optimisation of the number N of correctors, the algorithm’s gain and the corrector step size is described, and the impact of a number of BPMs and correctors becoming unavailable is addressed. The application of a MICADO algorithm to perform dispersion free steering, by reducing the beam orbit difference between two beams with different energies, is discussed. * B. Autin & Y. Marti, "Closed orbit correction of A.G. machines using a small number of magnets", CERN-ISR-MA/73-17, 1973.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP017
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP018	Beam-Based Beamline Element Alignment for the Main Linac of the 380 GeV Stage of CLIC	linac, alignment, collider, wakefield	465
	N. Blaskovic Kraljevic, D. Schulte CERN, Meyrin, Switzerland
	The extremely small vertical beam size required at the interaction point of future linear colliders, such as the Compact Linear Collider (CLIC), calls for a very small vertical emittance. The strong wakefields in the high frequency 12 GHz CLIC accelerating structures set tight tolerances on the alignment of the main linac’s beamline elements and on the correction of the beam orbit through them in order to mantain a small emittance growth. This paper presents the emittance growth due to each type of beamline element misalignment in the designed 380 GeV centre-of-mass energy first-stage of CLIC, and the emittance growth following a series of beam-based alignment (BBA) procedures. The BBA techniques used are one-to-one steering, followed by dispersion free steering and finally accelerating structure alignment using wakefield monitors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP018
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP025	Moving Long-range Beam-beam Encounters in Heavy-ion Colliders	proton, injection, collider, acceleration	488
	M.A. Jebramcik, J.M. Jowett CERN, Geneva, Switzerland
	Asymmetric ion beam collisions like proton-lead in the LHC or gold-deuteron in RHIC have become major components of heavy-ion physics programmes. The injection and ramp of two different ion species with the same magnetic rigidity and consequently unequal revolution frequencies generate moving long-range beam-beam encounters in the interactions regions of the collider. These encounters led to fast beam losses and can cause emittance blow-up as observed in RHIC in the early 2000s and, more recently, in 2015. Yet such effects are absent at the LHC so the difference between the two colliders requires explanation. Tools and models have been developed to describe the beam dynamics of moving long-range beam-beam encounters and to predict the evolution of emittance and other beam parameters. Besides presenting results for RHIC and the LHC we give an outlook for the HL-LHC and potential operational restrictions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP025
About •	paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPMP031	Operation and Performance of the Cern Large Hadron Collider During Proton Run 2	luminosity, operation, proton, injection	504
	R. Steerenberg, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, G.E. Crockford, J.-C. Dumont, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Lamont, E. Métral, D. Nisbet, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, M. Schaumann, M. Solfaroli, R. Suykerbuyk, G. Trad, J.A. Uythoven, S. Uznanski, D.J. Walsh, J. Wenninger, M. Zerlauth CERN, Geneva, Switzerland
	Run 2 of the CERN Large Hadron Collider (LHC) was successfully completed on 10th December 2018, achieving largely all goals set in terms of luminosity production. Following the first two-year long shutdown and the re-commissioning in 2015 at 6.5 TeV, the beam performance was increased to reach a peak luminosity of more than twice the design value and a colliding beam time ratio of 50%. This was accomplished thanks to the increased beam brightness from the injector chain, the high machine availability and the performance enhancements made in the LHC for which some methods and tools, foreseen for the High Luminosity LHC (HL-LHC) were tested and deployed operationally. This contribution provides an overview of the operational aspects, main limitations and achievements for the proton Run 2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP031
About •	paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPMP035	Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider	luminosity, collider, radiation, photon	516
	M.A. Valdivia García, F. Zimmermann CERN, Meyrin, Switzerland
	Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035
About •	paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPMP037	Updated High-Energy LHC Design	injection, proton, impedance, damping	524
	F. Zimmermann, D. Amorim, S.A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, J. Keintzel, R. Kersevan, V. Mertens, J. Molson, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann CERN, Geneva, Switzerland J.L. Abelleira, A. Abramov, E. Cruz Alaniz, H. Pikhartova, A. Seryi, L. van Riesen-Haupt JAI, Oxford, United Kingdom A. Apyan ANSL, Yerevan, Armenia J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco EPFL, Lausanne, Switzerland F. Burkart DESY, Hamburg, Germany Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, USA G. Guillermo Cantón CINVESTAV, Mérida, Mexico K. Ohmi, K. Oide, D. Zhou KEK, Ibaraki, Japan
	Funding: This work was supported in part by the European Commission under the HORIZON 2020 project ARIES no.730871, and by the Swiss Accelerator Research and Technology collaboration CHART. We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb₃Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP037
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB001	Low Emittance Tuning of FCC-ee	coupling, lattice, quadrupole, sextupole	574
	T.K. Charles The University of Melbourne, Melbourne, Victoria, Australia S. Aumon, B.J. Holzer, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001
About •	paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPRB003	Multi-Target Lattice for Muon Production From e⁺ Beam Annihilation on Target	target, positron, lattice, site	578
	O.R. Blanco-García LAL, Orsay, France M. Antonelli, M.E. Biagini, M. Boscolo, A. Ciarma, S. Guiducci, C. Vaccarezza, A. Variola INFN/LNF, Frascati, Italy G. Cesarini INFN-Roma, Roma, Italy F. Collamati INFN-Roma1, Rome, Italy R. Li Voti Sapienza University of Rome, Rome, Italy P. Raimondi ESRF, Grenoble, France
	The Low Emittance Muon Accelerator~(LEMMA) aims at producing small emittance muons from positron annihilation with electrons in a target. Given the low cross section of the production process, a large number of positrons on the target are required, exposing it to high power deposition and the beam to large degradation because of multiple scattering and bremstrahlung. A multi-target IP, and multi-IP line has been studied to reduce the power deposition per target and the degradation of the positron beam while preserving the number of muon pairs produced. The lattice copes with the focusing and transport of three beams at two different energies, the positron beam at 45 GeV, and µ⁺+ and µ⁻ beams at 22.5~GeV. Studies on the beam dynamics, number of targets, material and thickness of the targets are reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB003
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB011	Progress on Muon Ionization Cooling Demonstration with MICE	simulation, experiment, detector, framework	594
	C. Hunt Imperial College of Science and Technology, Department of Physics, London, United Kingdom V.C. Palladino INFN-Napoli, Napoli, Italy C.G. Whyte USTRAT/SUPA, Glasgow, United Kingdom
	Funding: STFC, NSF, DOE, INFN, CHIPP andd more The Muon Ionization Cooling Experiment (MICE) at RAL has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. Further studies are providing now more and deeper insight. Submitted by the chair of our MICE speakers bureau. If accepted, a member of the collaboration will soon be identified to present the contribution and will register immediately after.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB011
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB012	RECENT RESULTS FROM MICE ON MULTIPLE COULOMB SCATTERING AND ENERGY LOSS	scattering, detector, framework, acceleration	598
	C.G. Whyte USTRAT/SUPA, Glasgow, United Kingdom J.C. Nugent University of Glasgow, Glasgow, United Kingdom
	Funding: STFC, NSF, DOE, INFN, CHIPP and more Multiple Coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, it is known that the simulation code (GEANT4) available at the time overestimated the scattering of muons in low Z materials. Updates to GEANT4 have brought the simulations in line with the MuScat data and these new models can be validated over a larger range of momentum, 170-250 MeV/c, with MICE data. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in the spring of 2016 using a lithium hydride absorber and in the fall of 2017 using a liquid hydrogen absorber. The measurement in lithium hydride is reported here along with the preliminary measurements in liquid hydrogen. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are all compared with the Bethe-Bloch formula and with the predictions of various models, including the default GEANT4 model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB012
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPRB013	Focusing of High-Brightness Electron Beams with Active-Plasma Lenses	plasma, focusing, electron, experiment	601
	R. Pompili INFN/LNF, Frascati, Italy
	Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB013
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB023	Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam	rfq, experiment, polarization, acceleration	622
	H.Y. Yasuda University of Tokyo, Tokyo, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan N. Kawamura, T. Mibe, M. Otani KEK, Ibaraki, Japan Y. Kondo JAEA/J-PARC, Tokai-mura, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Numbers JP18J22129, JP18H03707. Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB023
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB062	nuSTORM Decay Ring	lattice, quadrupole, resonance, closed-orbit	716
	J.-B. Lagrange STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom R.B. Appleby, S.C. Tygier UMAN, Manchester, 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
	Precise neutrino cross section measurements and search for sterile neutrinos can be done with neutrino beams produced from muons decaying in a storage ring due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam would be captured. The storage ring has three options: a FODO solution with large aperture quadrupoles, a racetrack FFA (Fixed Field Alternating gradient) using the recent developments in FFAs and a hybrid solution of the two previous options. Machine parameters, linear optics design and beam dynamics of the hybrid solution are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB062
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB077	Results From the CBETA Fractional Arc Test	linac, cavity, MMI, betatron	751
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg BNL, Upton, Long Island, New York, USA
	We report on commissioning experiments of the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. The beam from the injector is accelerated by a linac with a 36 MeV design energy gain, is transported through a splitter line that uses conventional magnets, and finally into a four cell permanent magnet based fixed field alternating (FFA) gradient arc. We measure beam properties in the injector, calibrate the energy gain and phase of the linac cavities using time of flight to a BPM at the end of the linac. We scan individual cavity phases and pass beam through the cavities to determine the transverse offset of the individual cavities. We scan the beam position in the splitter BPMs to estimate and correct the nonlinearity in the BPM response. We tested our path length adjustment mechanism. We measure the dispersion and R56 in the FFA arc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB077
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB090	Simulation Challenges for eRHIC Beam-Beam Study	electron, proton, simulation, damping	785
	Y. Luo, F.J. Willeke BNL, Upton, Long Island, New York, USA Y. Hao FRIB, East Lansing, Michigan, USA J. Qiang LBNL, Berkeley, California, USA Y. Roblin, H. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The 2015 Nuclear Science Advisory Committee Long Rang Plan identified the need for an electron-ion collider (EIC) facility as a gluon microscope with capabilities beyond those of any existing accelerator complex. To reach the required high energy, high luminosity, and high polarization, the eRHIC design, based on the existing heavy ion and polarized proton collider RHIC, adopts a very small \beta-function at the interaction points, a high collision repetition rate, and a novel hadron cooling scheme. A full crossing angle of 22 mrad and crab cavities for both electron and proton rings are required. In this article, we will present the high priority R\&D items related to the beam-beam interaction studies for the current eRHIC design, the simulation challenges, and our plans and methods to address them. Recent progresses on this project are reported too.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB090
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB105	Measurement and Analysis of Beam Phase-space Distributions for the Fermilab Muon Campus accelerator complex	quadrupole, framework, experiment, simulation	810
	A. Ramirez University of Houston, Houston, Texas, USA D. Stratakis Fermilab, Batavia, Illinois, USA
	The Muon g-2 experiment at Fermilab is tasked with measuring the muon’s anomalous magnetic moment with high precision. Since the experiment requires large amounts of muons, it is imperative to systematically study the behavior of the beam along the transport line. Unfortunately, the available diagnostics only provide beam information in X-Y space. For a complete evaluation, information of the phase-space is required. This paper demonstrates a technique to measure the beam phase-space distribution by using a set of beam profiles. First, we establish the theoretical framework that describes the principle of the technique. Next, we apply the technique at four different locations along the accelerator delivery line. Finally, we compare our findings to predictions from tracking simulations. Our results indicate that the beam phase-space volume is conserved, along the beam delivery line, suggesting minimal loses and linear transport as expected by design. Compared to the simulations, there is good agreement in both horizontal and vertical plane with the former being at the 4% level while the latter being in the 15% level. Our proposed technique is expected to provide a promising approach for optimizing injection and thereby improving the performance of the Muon g-2 Experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB105
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB110	Simulation Study of the Emittance Measurements in Magnetized Electron Beam	solenoid, cathode, electron, gun	822
	S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft ODU, Norfolk, Virginia, USA J.F. Benesch, F.E. Hannon, G.A. Krafft, M.A. Mamun, G.G. Palacios Serrano, M. Poelker, R. Suleiman, S. Zhang JLab, Newport News, Virginia, USA
	Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177 Electron cooling of the ion beam is key to obtaining the required high luminosity of proposed electron-ion colliders. For the Jefferson Lab Electron Ion Collider, the expected luminosity of 10³⁴ 〖 cm〗^-2 s^-1 will be achieved through so-called ’magnetized electron cooling’, where the cooling process occurs inside a solenoid field, which will be part of the collider ring and facilitated using a circulator ring and Energy Recovery Linac (ERL). As an initial step, we generated magnetized electron beam using a new compact DC high voltage photogun biased at -300 kV employing an alkali-antimonide photocathode. This contribution presents the characterization of the magnetized electron beam (emittance variations with the magnetic field strength for different laser spot sizes) and a comparison to GPT simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB110
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB116	Laser Sculpted Cool Proton Beams	laser, linac, proton, simulation	826
	S.M. Gibson, L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom S.E. Alden, S.M. Gibson, L.J. Nevay JAI, Egham, Surrey, United Kingdom
	Funding: We acknowledge support by STFC grant ST/P003028/1 Hydrogen ion accelerators, such as CERN’s Linac4, are increasingly used as the front end of high power proton drivers for high energy physics, spallation neutron sources and other applications. Typically, a foil strips the hydrogen ion beam to facilitate charge-exchange injection of protons into orbits of high energy accelerators, in which the resulting emittance is dominated by phase-space painting. In this paper, a new method to laser extract a narrow beam of neutralised hydrogen from the parent H⁻ ion beam is proposed. Subsequent foil stripping and capture of protons into a storage ring generates cool proton bunches with significantly reduced emittance compared to the parent beam. The properties of the extracted proton beam can be precisely controlled and sculpted by adjusting the optical parameters of the laser beam. Recirculation of the parent beam allows time for space-charge effects to repopulate the emittance phase space prior to repeated laser extraction. We present particle tracking simulations of the proposed scheme, including the laser-particle interaction with realistic optical parameters and show the resulting emittance is reduced. Developments for an experimental demonstration of a laser controlled particle beam are outlined. In principle, the proposed scheme could considerably reduce the emittance of protons bunches injected into an accelerator, such as the LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB116
About •	paper received ※ 16 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS003	Superconducting LINAC Design Upgrade in View of the 100 MeV MYRRHA Phase I	linac, cavity, cryomodule, lattice	837
	F. Bouly, M.A. Baylac LPSC, Grenoble Cedex, France A. Gatera SCK•CEN, Mol, Belgium D. Uriot CEA-DRF-IRFU, France
	Funding: Part of this work supported by the European Atomic Energy Community (EURATOM) H₂020 Programme under grant agreement n°662186 (MYRTE project). 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 Belgium government the project has entered in its phase I: which consists in the development and the construction of the linac first part, up to 100 MeV. We review the design updates of the superconducting linac, with its enhanced fault-tolerance capabilities. The linac capabilities at 100 MeV (Phase I) and 600 MeV (ADS operation) are exposed and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS003
About •	paper received ※ 23 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS006	Final Results of the SPIRAL2 Injector Commissioning	rfq, LEBT, MMI, linac	848
	R. Ferdinand, M. Di Giacomo, H. Franberg, J.-M. Lagniel, G. Normand, A. Savalle GANIL, Caen, France D. Uriot CEA-DRF-IRFU, France
	The SPIRAL2 injector, made up of a 5 mA p-d ion source, a 1 mA heavy ion source (up to A/Q = 3) and a CW 0.75 MeV/u RFQ, has been commissioned in parallel with the superconducting linac installation. This com-missioning is successfully completed now and the Diag-nostic plate (D-plate) used to characterize the injector beams is removed. This paper presents the results ob-tained with the reference particles (H⁺, 4He2+, 18O6+ and 40Ar14+) and a comparison with the simulations. The connexion to the SC linac and the future linac beam commissioning is briefly described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS006
About •	paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS032	New Beam Dynamics Simulations for the FAIR p-Linac RFQ	rfq, simulation, linac, LEBT	921
	M. Syha, H. Hähnel, U. Ratzinger, M. Schuett IAP, Frankfurt am Main, Germany
	The construction of a 3.3m Ladder-RFQ at IAP, Goethe University Frankfurt, has been finished successfully last summer. This RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-Linac at FAIR. Along the acceleration section the parameters modulation, aperture and synchronous phase are varied linearly with cell number, which differs from former designs from IAP Frankfurt. The ratio of transversal vane curvature radius to mid-cell radial aperture and the vane radius itself are constant. The development of an adequate beam dynamics design was done with the aid of the RFQGen-code and in close collaboration with the IAP resonator design team. The RFQ beam dynamics design could be successfully reproduced with the TOUTATIS-routine of CEAs TraceWin-code. Several new beam dynamics simulations were performed on the design. Among these were current and Twiss parameter studies as well as simulations concerned with the investigation of longitudinal entrance and exit gap field effects. Others were based on new measurements in the LEBT-line performed by the GSI** Ion Source Group in April 2019. In the near future, further LEBT measurements and subsequent simulations (among other to design a well-fitting cone for the RFQ), as well as mechanical error studies in TOUTATIS, will follow. Institute of Applied Physics Facility for Antiproton and Ion Research French Alternative Energies and Atomic Energy Commission **GSI Helmholtz Centre for Heavy Ion Research
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS032
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS067	The Progress in Physics Design of HEPS LINAC	linac, wakefield, bunching, electron	1008
	C. Meng, D.Y. He, X. He, J.Y. Li, Y.M. Peng, S.C. Wang, O. Xiao, J.R. Zhang, S.P. Zhang IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance light source to be built in China. The injector is composed of a 500-MeV Linac and a full energy booster. According to the study and com-missioning consideration of on-axis swap-out injec-tion system, a high bunch charge injector is desirable and a Linac that can provide 7nC per bunch electron beam to booster is needed. This paper present different bunching system schemes and the performance of different schemes are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS067
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPTS073	Bunching System Optimization Based on MOGA	bunching, linac, electron, solenoid	1018
	S.P. Zhang, J.Y. Li, C. Meng IHEP, Beijing, People’s Republic of China
	Multiobjective Genetic Algorithms (MOGA) is effective in dealing with optimization problems with multiple objectives. The bunching system of the High Energy Photon Source (HEPS) linac adopts a traditional bunching system for compressing electron beams with a pulse charge of 4 nC. The bunching system is optimized using MOGA. The optimization include minimizing the normalized emittance and maximizing transmission efficiency. The optimization results have reached the design target, and are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS073
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS083	Beam Dynamics Simulation with an Updated Model for the ESS Ion Source and Low Energy Beam Transport	LEBT, rfq, solenoid, simulation	1042
	E. Nilsson, M. Eshraqi, J.F. Esteban Müller, Y. Levinsen, N. Milas, R. Miyamoto ESS, Lund, Sweden
	Beam dynamics simulation of the ion source (IS) and low energy beam transport (LEBT) of the European Spallation Source (ESS) Linac is conducted with TraceWin and IBSimu code. TraceWin allows multi-particle tracking based on a particle-in-cell space-charge solver and is the standard simulation tool of the whole ESS Linac. IBSimu is based on a Vlasov solver and allows to simulate beam extraction from plasma as well as the beam transport in the LEBT. In preparation for beam commissioning of the IS and LEBT in the ESS Linac tunnel, which started in September 2018 and is ongoing as of the timing of writing this paper, the simulation models of the IS and LEBT in these two codes were updated. This paper reports the effort for these updates, including the beam distribution out of the IS, electromagnetic field map of the LEBT solenoid, more realistic aperture structure in the LEBT, as well as updated LEBT solenoids scan simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS083
About •	paper received ※ 17 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS084	ESS Low Energy Beam Transport Tuning During the First Beam Commissioning Stage	solenoid, LEBT, MMI, rfq	1046
	R. Miyamoto, C.S. Derrez, E. Laface, Y. Levinsen, N. Milas, A.G. Sosa, R. Tarkeshian, C.A. Thomas ESS, Lund, Sweden
	Beam commissioning of the ion source (IS) and low energy beam transport (LEBT) of the European Spallation Source is ongoing on its site as of writing this paper and continues until June 2019. The LEBT consists of two solenoids with integrated dipole correctors to steer, focus, and match the high current divergent beam out of the IS to the following radio frequency quadrupole (RFQ). It is also equipped with a suite of diagnostics devices to provide a full characterization of the beam for achieving a good transport within the LEBT, optimizing the matching to the RFQ, and also providing references to numerical simulations. This paper presents results of beam characterization campaign from the ongoing beam commissioning period, including the matching at the RFQ interface based on emittance sampling for varied strengths of the solenoids and verification of the linear model for the trajectory and beam envelope.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS084
About •	paper received ※ 21 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPTS086	Identification and Compensation of Betatronic Resonances in the Proton Synchrotron Booster at 160 Mev	resonance, space-charge, injection, proton	1054
	A. Santamaría García, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, G.P. Di Giovanni, B. Mikulec CERN, Geneva, Switzerland F. Asvesta NTUA, Athens, Greece H. Rafique University of Manchester, Manchester, United Kingdom
	The Proton Synchrotron Booster (PSB) is the first circular accelerator in the injector chain to the Large Hadron Collider (LHC) and accelerates protons from 50 MeV to 1.4 GeV. The PSB will need to deliver two times the current brightness after the LHC Injectors Upgrade (LIU) in order to meet the High Luminosity LHC (HL-LHC) beam requirements. At the current injection energy a large incoherent space charge tune spread limits the brightness of the beams, which is one of the main motivations to increase the injection energy to 160 MeV with the injection provided by Linac4, a new H⁻ linear accelerator. The higher injection energy will allow doubling the beam intensity while maintaining a space charge tune spread similar to current values. The degradation of the beam brightness due to the tune spread can be minimized with a proper choice of working point and an efficient compensation of resonances. In this paper, we present the measurement of the betatronic resonances in the four rings of the PSB at 160 MeV before the Long Shutdown 2, as well as the results of a proposed compensation scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS086
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS087	Transverse Emittance Studies at Extraction of the CERN PS Booster	optics, operation, booster, injection	1058
	F. Antoniou, S.C.P. Albright, F. Asvesta, H. Bartosik, G.P. Di Giovanni, V. Forte, M.A. Fraser, A. Garcia-Tabares, A. Huschauer, B. Mikulec, T. Prebibaj, A. Santamaría García, P.K. Skowroński CERN, Meyrin, Switzerland F. Asvesta NTUA, Athens, Greece T. Prebibaj National Technical University of Athens, Zografou, Greece
	Transverse emittance discrepancy in the beam transfer between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is observed in operational conditions for the LHC beams at CERN. The ongoing LHC Injectors Upgrade (LIU) project requires a tight budget for beam degradation along the injector chain and therefore the reason for this emittance discrepancy needs to be understood. Systematic measurements have been performed for various beam characteristics (beam intensity, transverse and longitudinal emittance). In this paper, a comparison between the emittance measurements using all available beam instrumentation with different emittance computation algorithms is presented. The results are compared to measurements at PS injection. Furthermore, the impact on the LIU project requirements for the emittance preservation along the LHC Injectors Complex is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS087
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPTS089	Transverse Beam Dynamics Studies With High Intensity LHC Beams in the SPS	injection, octupole, impedance, electron	1062
	M. Carlà, H. Bartosik, M.S. Beck, L.R. Carver, V. Kain, G. Kotzian, K.S.B. Li, G. Rumolo, C. Zannini CERN, Geneva, Switzerland
	In order to reach the target beam parameters of the LHC injectors upgrade (LIU), about twice the presently operational intensity of LHC type beams has to be achieved. Although the planned upgrade of the main RF system will occur during the long shutdown, a series of measurements have been performed to assess the beam dynamics challenges with these very high intensity beams on the long SPS injection plateau. Bunch-by-bunch transverse emittance blow-up measurements suggested the presence of electron-cloud. After a period of running with the high intensity beam for a couple of days, a clear improvement of beam quality was observed which is attributed to scrubbing. In addition, a horizontal headtail instability is encountered for the usual operational settings of chromaticity and transverse damper. The stability limit as a function of chromaticity and Landau octupole settings has been explored and will be discussed, together with possible sources of the instability and mitigation strategies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS089
About •	paper received ※ 06 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS096	Linac4: Reliability Run Results and Source Extraction Studies	extraction, linac, simulation, plasma	1090
	D. Noll, G. Bellodi, S.B. Bertolo, F.D.L. Di Lorenzo, J.-B. Lallement, J. Lettry, A.M. Lombardi, C.M. Mastrostefano, B. Mikulec, M. O’Neil, S. Schuh, R. Wegner CERN, Meyrin, Switzerland
	Linac4, a 160 MeV, 352.2 MHz linear accelerator, has been fully commissioned and will take its place as new injector to the CERN chain of accelerators during the long shutdown (LS2) in 2019-2020. In the past year, it has been continuously providing beam during a test run to assess its reliability in view of the connection to the LHC injector chain. The target reliability of more than 90% has been demonstrated during the accumulated nine months of run in 2017 and 2018. The beam quality at 160 MeV is suitable for producing all beams for the CERN physics program of today. Nevertheless, the limited peak current of 30mA might be a limitation for future high intensity programs. The bottleneck has been identified at the low energy end of the accelerator. In the meantime, beam extraction and low energy beam transport studies are ongoing at a dedicated test stand with the goal to reach beam currents from the pre-injector up to 45 mA. We will present the status of the modelling of the pre-injector and possible solutions to reach higher beam currents from the RFQ along with results from the reliability run.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS096
About •	paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPTS097	Updates on Alternative Pre-Booster Ring Design and Wiggler Magnet Considerations of SPS for the FCC e⁺e⁻ Injector	damping, wiggler, injection, extraction	1094
	O. Etisken Ankara University, Faculty of Sciences, Ankara, Turkey F. Antoniou, Y. Papaphilippou, T. Tydecks CERN, Meyrin, Switzerland A.K. Çiftçi Izmir University of Economics, Balçova/Izmir, Turkey
	The Future Circular e⁺e⁻ Collider (FCC- e⁺e⁻) injector complex needs to produce and to transport a high-intensity e⁺e⁻ beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and designing a completely new ring. The purpose of this paper is to explore the needs and parameters of the existing SPS, to investigate wiggler magnet options for SPS, and provide an updated study of alternative accelerator ring design with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the parameters of both choices are established, including the optics design, layout update and considerations for non-linear dynamics optimization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS097
About •	paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS098	A Primary Electron Beam Facility at CERN	linac, electron, injection, proton	1098
	Y. Papaphilippou, R. Corsini, Y. Dutheil, L.R. Evans, B. Goddard, A. Grudiev, A. Latina, S. Stapnes CERN, Meyrin, Switzerland T.P.Å. Åkesson Lund University, Department of Physics, Lund, Sweden
	This paper describes the concept of a primary electron beam facility at CERN, to be used for dark gauge force and light dark matter searches. The electron beam is produced in three stages: A Linac accelerates electrons from a photo-cathode up to 3.5 GeV. This beam is injected into the Super Proton Synchrotron, SPS, and accelerated up to a maximum energy of 16 GeV. Finally, the accelerated beam is slowly extracted to an experiment, possibly followed by a fast dump of the remaining electrons to another beamline. The beam parameters are optimized using the requirements of the Light Dark Matter eXperiment, LDMX, as benchmark.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS098
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS100	Transverse Emittance Measurement in the CERN Proton Synchrotron in View of Beam Production for the High-Luminosity LHC	brightness, proton, optics, betatron	1106
	E. Senes, J. Emery, V. Forte, M.A. Fraser, A. Guerrero, A. Huschauer, F. Roncarolo, J.L. Sirvent, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade project the improvements required to achieve the parameters of the future beams for the High-Luminosity LHC are being studied and implemented. In order to deliver high brightness beams, control over the beam intensity and emittance is fundamental. Therefore, a highly accurate and reliable transverse emittance measurement is essential. Presently at the CERN Proton Synchrotron, the only operationally available emittance monitors not impacting the facility beam production are the flying wire scanners used to measure the circulating beam profile. The wire scanners will be replaced with a new generation in the next two years and a prototype is already installed. The prototype has been commissioned with beams featuring a wide range of intensities and emittances. This paper evaluates the performance of the prototype with respect to the present system via beam-based measurements. The transverse emittance measurement is discussed, considering the different potential error contributions to the measurement, such as knowledge of the machine optics and the dispersive contribution to the beam size.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS100
About •	paper received ※ 02 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS101	Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation	simulation, proton, scattering, brightness	1110
	A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis CERN, Geneva, Switzerland E. Senes Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS105	The High Brightness Photo-injector for THz CUR/VUV FEL at NSRRC	radiation, electron, quadrupole, linac	1125
	A.P. Lee, M.C. Chou, H.P. Hsueh, J.-Y. Hwang, W.K. Lau NSRRC, Hsinchu, Taiwan P. Wang NTHU, Hsinchu, Taiwan
	A high brightness photo-injector has been build for THz coherent undulator radiation and VUV free electron laser test facility at NSRRC. In the first phase, the photo-injector was used to produce ultra-short electron bunches for THz CUR generation. The electron beam is generated form a photocathode rf gun followed by a solenoid for emittance compensation. Then A 5.2 m S-band linac accelerates the electron beam and compresses the beam by velocity bunching. Since the beam emittance will grow during the velocity bunching process, a solenoid system was installed to reduce the emmitance growth. Downstream the linac, a quadruple magnet was use for emittance measurement by quadruple scan method and the bunch length was measured by the coherent transition radiation. Finally, the ultra-short electron bunch with about few hundreds picoseconds passes through a U100 planer undulator can produce THz coherent undulator radiation. The instrument setup and results of measurement are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS105
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPTS112	Matrix Approach to Decouple Transverse-Coupled Beams	coupling, quadrupole, solenoid, DTL	1144
	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
	Funding: Work supported by the National Key Research and Development Program of China (grant number 2016YFC0105408). Transverse emittances, especially vertical emittance, are strictly required in the synchrotrons with multi-loop injection. Transverse emittances easily grow up if transverse beam phase spaces are coupled. The growth of the transverse emittance can be restained by decoupling the beam phase spaces. Based on the transfer matrix calculation, it can be theoretically proved that the decoupling can be implemented for general situations. A minimum number of rotated quadrupoles required for decoupling is given. Two quadrupoles can decouple the beam and suppress its emittance growth to 1% in the coupling DTL case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS112
About •	paper received ※ 28 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS120	Commissioning of the New Experimental FODO Line at the SNS Beam Test Facility	rfq, MMI, simulation, optics	1164
	A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, V. Tzoganis, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA Z.L. Zhang UTK, Knoxville, Tennessee, USA
	The SNS Beam Test Facility consists of a 2.5MeV proton accelerator and a beam line with various diagnostics for high intensity beam dynamics study. A FODO line consisting of 19 quadrupole magnets and a large dynamic range emittance monitor has been added recently. The new setup is design for experimental study of mechanisms of halo formation in mismatched high intensity beams. We present results of the new beam line commissioning with beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS120
About •	paper received ※ 07 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUYPLM1	XFEL Performance Achieved at PAL-XFEL	FEL, undulator, electron, photon	1182
	H. Heo, M.-H. Cho, J.H. Han, H.-S. Kang, C. Kim, G. Kim, M.J. Kim, J.H. Ko, H.-S. Lee, C.-K. Min, I.H. Nam, K.-H. Park, C.H. Shim, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) successfully completed the commissioning of SASE and started user operation in late 2016. Since then, the facility has demonstrated excellent stability with very small timing jitter of about 20 fs, and commissioned the self-seeding system over a wide range of photon energies, etc. The talk will provide an overview of the last three years at the PAL-XFEL, including some detailed experimental results, as well as future prospects for the laboratory.
	Slides TUYPLM1 [7.516 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM1
About •	paper received ※ 20 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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TUZPLM2	Optics Measurements at SuperKEKB Using Beam Based Calibration for BPM and BBA	quadrupole, optics, betatron, coupling	1198
	H. Sugimoto, H. Koiso, K. Mori, A. Morita, Y. Ohnishi, M. Tejima KEK, Ibaraki, Japan
	The beam-based calibration(BBC) technique for Beam-Position-Monitor(BPM) is applied in order to establish reliable optics measurement. In the BBC, a response model between beam position, charge and output signals of the BPM electrodes are introduced to calibrate the relative gain of the BPM electrodes. The gains are adjusted by total squares fitting so that the model reproduces the measured BPM signals. The Beam-Based Alignment(BBA) is also performed to determine the magnetic center of a quadrupole. Using BBC and BBA, the performance of the BPM system and optics correction are successfully improved. This talk presents what we experienced during the beam commissioning focusing on beam optics measurement and some details on the beam-based calibration scheme for BPM system.
	Slides TUZPLM2 [15.911 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLM2
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUZPLS2	Beam Dynamics Study in the HEPS Storage Ring	lattice, storage-ring, photon, brightness	1203
	Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.
	Slides TUZPLS2 [9.517 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP044	Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems	vacuum, impedance, photon, experiment	1347
	G.Y. Hsiung NSRRC, Hsinchu, Taiwan
	Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW004	Cls 2.2: Ultra-Brilliant Round Beams Using Pseudo Longitudinal Gradient Bends	quadrupole, injection, lattice, coupling	1385
	L.O. Dallin CLS, Saskatoon, Saskatchewan, Canada
	A preliminary design for a new storage for the Canadian Light Source was presented at IPAC’18 (Dallin). More recently a reconfigured lattice was presented at the 6th DLSR workshop. This lattice employed large βy and small βx in the straights. This has several advantages including: increased transverse coherence and brighter beams at small coupling; round beams at small coupling; flatter βy through the straights; and possible off-axis vertical injection at small amplitudes. Most recently longitudinal gradients in the dipoles have been implemented. This has lead to the unit cell bends being replaced by a ’pseudo longitudinal gradient’ bend array: bend1-bend2-bend1. This results in smaller emittance with simple magnet designs while maintaining adequate dynamic aperture for off-axis injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW004
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW009	THE ESRF FROM 1988 TO 2018, 30 YEARS OF INNOVATION AND OPERATION	operation, SRF, vacuum, injection	1400
	J.-L. Revol, L. Farvacque, L. Hardy, P. Raimondi ESRF, Grenoble, France
	In 1988, eleven European countries joined forces to build the European Synchrotron Facility in Grenoble [France]. The ESRF was the first third-generation light source worldwide. After 30 years of innovation and user operation, the present storage ring was shut down to leave room for a new and brighter source. This paper describes the evolution of the facility from its origin to the Ex-tremely Bright Source (EBS). Firstly, the operational aspects including reliability and beam modes are consid-ered. This is followed by the presentation of the progress of lattice and the implementation of top-up. Finally, the development of the radio frequency and vacuum systems are discussed. To conclude, the lessons learned from 30 years operation are summarized, especially in view of EBS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW009
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW011	Status of the PETRA IV project	lattice, brightness, timing, synchrotron	1404
	I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang DESY, Hamburg, Germany
	Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW012	Sensitivity Studies of the PETRA IV Lattice	alignment, simulation, site, resonance	1408
	I.V. Agapov DESY, Hamburg, Germany
	As the machine with the smallest emittance among the planned fourth-generation hard x-ray synchrotron light sources, PETRA IV will have very demanding requirements on magnet alignment and stability. Several developments to address mechanical and beam-based stabilization have been started in connection to that. Here we summarize the alignment and field error tollerances resulting from startup and commissioning simulations of the main ring. Novel high level control tools will be required to assure smooth operation of the machine; progress in their development and beam test results at PETRA III will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW012
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW013	Tune and Chromaticity Optimization at Bessy II for the Transverse Resonant Island Bucket Optics	optics, simulation, photon, resonance	1411
	F. Armborst, P. Goslawski, A. Jankowiak HZB, Berlin, Germany
	Funding: Federal Ministry of Education and Research Transverse Resonant Island Buckets (TRIBs ) correspond to a second stable orbit, longitudinally winding around the core orbit in the transverse x-x^′-phasespace. The exploitation possibilities for stable TRIBs are under investigation at the third generation light source BESSY II in Berlin. The applicability for bunch separation is a main subject of these studies. Stable operation of TRIBs optics with a single or few bunches on the second orbit and a multibunch train on the main orbit has been shown . Photons emitted on the second orbit are well separated from those of the main orbit at all beamlines. This provides the possibility of bunch separation by beamline adjustment for the timing community without significant impact on the average brightness for other users. Simulations based on linear optics from closed orbits (LOCO) and on nonlinear optics derived from the measured chromaticity and tune shift with action (TSWA) predict this separation well. Friendly user experiments in 2018 confirmed these results. The scheduled upgrade BESSY VSR ** features simultaneously stored long and short bunches. Then TRIBs optics would in principle enable the separation of the different bunches at every beamline offering unique possibilities to our users. Simulations and measurements aiming to investigate further possible optimization of the TRIBs optics are presented. * F. Armborst, P. Goslawski et al, DOI: 10.18429/JACoW-IPAC2018-TUPML052 P. Goslawski, F. Armborst et al. DOI: 10.18429/JACoW-IPAC2017-WEPIK057 * A. Jankowiak et al., DOI: 10.5442/R0001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW013
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPGW018	PETRA IV Study with Non-Interleaved Sextupole Scheme	sextupole, lattice, storage-ring, optics	1430
	H.C. Chao, R. Brinkmann, X.N. Gavaldà DESY, Hamburg, Germany
	This study is an attempt to design PETRA IV storage ring, which is an upgrade from PETRA III toward diffraction-limit synchrotron light source, based on the non-interleaved sextupole scheme. The lattice is constructed by mixing different types of cells. There are two basic building blocks. The double minus identity (DMI) cell dedicated for the chromaticity correction with non-interleaved sextupoles is tightly built up, while the combined function FODO cell with dispersion suppressors provides straights with small beta functions ideally for undulators. In addition, the hybrid section including a 10-m long super insertion device (ID) is custom-made to adapt to DESY’s current site plan. The beam dynamic behaviors are simulated and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW018
About •	paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW028	Low Energy Beam Transport System for MESA	cavity, laser, experiment, solenoid	1461
	C. Matejcek, K. Aulenbacher, S. Friederich IKP, Mainz, Germany
	An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. The present setup includes the chopper- and bunching system. The devices are of most importance in order to achieve sufficient bunch compression particularely at higher bunch charges and currents. With the circular deflecting cavity of the chopper system it is possible to measure the longitudinal dimension of the bunches upstream of the buncher whereas downstream the longitudinal size will be measured by Smith Purcell radiation. Based on experimental results obtained from this setup we will discuss the beam parameter and compare them with simulations of the beamline.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW028
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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Paper

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Other Keywords

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MOZZPLS2

Positron Driven Muon Source for a Muon Collider: Recent Developments

target, damping, collider, positron

49

M.E. Biagini, M. Antonelli, O.R. Blanco-García, M. Boscolo, A. Ciarma, A. Giribono, S. Guiducci, C. Vaccarezza, A. Variola
INFN/LNF, Frascati, Italy
A. Bacci
INFN-Milano, Milano, Italy
M. Bauce, F. Collamati
INFN-Roma1, Rome, Italy
G. Cesarini
INFN-Roma, Roma, Italy
I. Chaikovska, R. Chehab
LAL, Orsay, France
S.M. Liuzzo, P. Raimondi
ESRF, Grenoble, France
D. Lucchesi
Univ. degli Studi di Padova, Padova, Italy
N. Pastrone
INFN-Torino, Torino, Italy

The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related to muon production, cooling, accumulation and acceleration. The Low Emittance Muon Accelerator (LEMMA) concept *,** presents in this paper an upgraded layout of a positron driven muon source. The positron beam, stored in a ring with high energy acceptance and low emittance, is extracted and driven in a push-pull configuration to a multi-target system, to produce muon pairs at threshold on the target’s electrons. This solution alleviates the issues related to the power deposited and the integrated Peak Energy Density Deposition on the targets. Muons produced in the multi-target system will then be accumulated in many parallel rings before acceleration and injection in the collider. A special multi-target line lattice has been designed to cope with the focusing of both the positron and muon beams. Studies on the number, material and thickness of the targets have been carried out. A general layout of the overall scheme and a description is presented, as well as plans for future R&D.
* M. Antonelli, P. Raimondi, INFN-13-22/LNF, 2013
** M. Boscolo, M. Antonelli, O.R. Blanco-Garcia, S. Guiducci, S. Liuzzo, P. Raimondi, F. Collamati, Phys. Rev. Accel. Beams, vol. 21, p. 061005, 2018

Slides MOZZPLS2 [4.360 MB]

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MOPGW015

Notes on Linear Theory of Coupled Particle Beams with Equal Eigenemittances

betatron, linear-dynamics, synchrotron

98

V. Balandin, N. Golubeva
DESY, Hamburg, Germany

We consider some aspects of the linear theory of coupled particle beams with equal eigenemittances and compare them with the one dimensional Courant-Snyder theory.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW015

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MOPGW019

Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee

lattice, simulation, optics, coupling

112

D. El Khechen, K. Oide, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW020

Numerical Calculation of Micro Bunching in BERLinPro Due to Space Charge and CSR Effects

bunching, space-charge, linac, optics

116

B.C. Kuske, A. Meseck
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
BERLinPro is an Energy Recovery Linac Project, currently being set up at the Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany. BERLinPro is a small demonstrator for ERL technology and applications. Due to the low energy of 50, resp. 32MeV, space charge plays a dominant role in the beam dynamics. Micro-bunching, due to unavoidable shot noise from the cathode in combination with space charge, is seen in the merger as well as in the recirculator. Coherent synchrotron radiation (CSR) can amplify this bunching, as well as micro-bunching can enhance CSR losses. With the release of OPAL 2.0** in May 2018, for the first time, an open source, highly parallel tracking code is available, that is capable of numerically calculating both effects, space charge and CSR, simultaneously. The calculations are compared to earlier results*, that used analytical formulas on tracked, space charge dominated bunches.
* "On space charge driven microbunching instability in BERLinPro", PhD thesis, S.D.Rädel, Humboldt Universität zu Berlin, 2017
** http://amas.web.psi.ch/docs/opal/opal_user_guide-2.0.0.pdf

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MOPGW022

Achromatic Isochronous Mode of the ESR at GSI

optics, sextupole, experiment, detector

124

S.A. Litvinov, M. Steck
GSI, Darmstadt, Germany

The isochronous optics of the ESR is a unique ion-optical setting in which the ring is operated as a Time-of-Flight Mass-Spectrometer and is used for direct mass measurements of short-lived exotic nuclei. The present isochronous optics had been performed only making a negative dispersion in the straight sections of the ESR of about -7 m. This negative dispersion makes the injection into the ESR very complicated and strict the transmission of the ions in the ring. Moreover, the non-achromatism of the ESR brings a supplementary uncorrectable first-order transverse contribution to the revolution time. In order to make the ESR achromatic, to improve injection and the isochronicity a new achromatic isochronous optics has been calculated and will be presented here in details.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW022

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW024

Measurements of the GSI Transfer Beam Lines Ion Optics

quadrupole, extraction, experiment, storage-ring

131

M. Sapinski, O. Geithner, S. Reimann, P. Schütt, M. Vossberg, B. Walasek-Höhne
GSI, Darmstadt, Germany
C. Heßler
CERN, Meyrin, Switzerland

GSI High Energy Beam Transfer lines (HEST) link the SIS18 synchrotron with two storage rings (Experimental Storage Ring and Cryring) and six experimental caves. The recent upgrades to HEST beam instrumentation enables precise measurements of beam properties along the lines and allow for faster and more precise beams setup on targets. Preliminary results of some of the measurements performed during runs in 2018 and 2019 are presented here. The focus is on response matrix measurements and quadrupole scans performed on HADES beam line. The errors and future improvements are discussed.

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paper received ※ 15 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPGW028

Study for the Alignment of Focusing Solenoid of ARES RF Gun and Effect of Misalignment of Solenoid on Emittance of Space Charge Dominated Electron Beam

solenoid, alignment, electron, gun

147

S. Yamin, R.W. Aßmann, B. Marchetti
DESY, Hamburg, Germany

SINBAD (Short and INnovative Bunches and Accelerators at DESY) facility will host multiple experiments relating to ultra-short high brightness beams and novel experiments with ultra-high gradient. ARES (Accelerator Research Experiment at SINBAD) Linac is an S-band photo injector to produce such electron bunches at around 100 MeV. The Linac will be commissioned in stages with the first stage corresponding to gun commissioning. In this paper, we present studies about the scheme adopted for the alignment of focusing solenoid for the ARES gun. The method is bench marked using ASTRA simulations. Moreover the effect of misalignment of the solenoid on the emittance of space charge dominated scheme and its compensation is also discussed.

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paper received ※ 26 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPGW037

Dynamic Variation of Chromaticity for Beam Instability Mitigation in the 3-GeV RCS of J-PARC

simulation, extraction, injection, impedance

171

P.K. Saha, H. Harada, H. Hotchi, Y. Shobuda, T. Takayanagi, F. Tamura, Y. Watanabe
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We have studied many other dynamic approaches from that reported in the IPAC 2018 for transverse beam instability mitigation in the presence of strong space charge in the 3-GeV RCS of J-PARC. One of such a method is the introduction of an excess of chromaticity from that of natural chromaticity by reversing the sextupole magnetic fields from the middle of the acceleration cycle. The benifits of this method are twofold. It allows to utilize sextupole for chromaticty correction at lower energy and also mitigate the beam instability at higher energy because of introducing higher chromaticity. We first carried out numerical simulations by using ORBIT code, experimentally verified and then applied for the machine operation. The detail of simulation and measurements results are presented in this paper.

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MOPGW038

Collimator’s Impact Into the Transverse Emittance Growth at KEK Compact ERL

wakefield, simulation, operation, FEL

174

O.A. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, Y. Tanimoto
KEK, Ibaraki, Japan

In high-intensity particle accelerators, unwanted trans-verse and longitudinal wakefields arise when the high-charge particle beam passes through the narrow chambers or locations with small transverse apertures, such as collimator jaws. Transverse wakefields impose a transverse kicks to the beam, changing its shape, and leading to the growth of the transverse emittance. Longitudinal wakes cause the beam energy losses, heating of the narrow chambers etc. In the present study we investigated the collimator’s impact to the beam. Thus, we evaluated the collimator’s wakefields through the CST simulations. We estimated the corresponding transverse kicks and longitudinal wakes. In the summary simulation results were cross-checked with correspondent analytical expressions.

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MOPGW040

Beam Optics Design of the Superconducting Region of the JAEA ADS

linac, cavity, controls, lattice

181

B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo.

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MOPGW048

Design Study of an Electron Storage Ring for the Future Plan of Hiroshima Synchrotron Radiation Center.

storage-ring, synchrotron, radiation, synchrotron-radiation

200

S. Matsuba, M. Katoh, K.S. Shimada
HSRC, Higashi-Hiroshima, Japan
K. Harada
KEK, Ibaraki, Japan
K. Kawase
QST, Tokai, Japan

Hiroshima synchrotron radiation center equips a 700 MeV electron storage ring nicknamed HiSOR. It has been operated for more than 20 years. The emittance of HiSOR is 400 nm, which is larger by one or more orders of magnitude than typical modern synchrotron light sources. Therefore, as the future plan of the facility, a new low emittance storage ring is desired. Several designs have been examined. In the newest version, we have selected the lattice structure similar to ASTRID 2 compact light source in Aarhus University, Denmark. The design goal is the energy of around 500 MeV, the circumference shorter than 50 m and the emittance smaller than 10 nm with straight sections for undulators more than 4. In this conference, we report the latest result from the design study.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW048

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paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW054

Study on Spherical Aberration Correction of Solenoid Lens in Ultrafast Electron Diffraction

electron, induction, solenoid, focusing

213

Y.T. Yang, K. Fan, J.J. Li
HUST, Wuhan, People’s Republic of China
Y. Song
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China

High electron beam quality is required in Ultrafast Electron Diffraction (UED) to achieve high spatial resolution. However, aberrations mainly induced by solenoid lens will deteriorate the beam quality and limit the resolution. Spherical aberration introduces the largest distortion which is unavoidable in the case of static cylindrically symmetric electromagnetic fields on the basis of Scherzer’s theorem. In order to reduce the spherical aberrations, different models have been designed which are composed of three symmetrical lens and one asymmetrical lens. We obtain the magnetic field distribution and calculate the aberration of each model by OPERA, and the result is that the solenoid without poles has the minimum aberration and meets the design requirement best.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW054

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paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPGW070

Longitudinal Stability of the Hollow Ion Bunches After Momentum Slip-Stacking in the CERN SPS

simulation, damping, synchrotron, proton

254

T. Argyropoulos, A. Lasheen, D. Quartullo, E.N. Shaposhnikova
CERN, Geneva, Switzerland

Momentum slip-stacking is planned to be used for the lead ion beams in the CERN SPS to double the beam intensity for the High-Luminosity LHC project. During this RF manipulation two SPS batches, controlled by two independent RF systems, are going to be interleaved on an intermediate energy plateau, reducing the bunch spacing from 100 to 50 ns. However, there are limitations how close the frequencies of two RF systems can approach each other, resulting in a hole in the longitudinal bunch particle distribution due to the offset in energy of the recaptured bunches. After filamentation, these bunches should be further accelerated to the SPS top energy, before extraction to the LHC. Macro-particle simulations have shown that Landau damping is lost for the bunches with the smallest longitudinal emittances in the batch, causing un-damped oscillations of the bunch core after recapture. The standard application of an additional, fourth harmonic RF system, successfully used in proton operation, was not able to damp the oscillations at top energy, while it was necessary to switch it on from the moment of recapture. In this paper the longitudinal stability of the bunches after slip-stacking is studied in more details both by macro-particle simulations and analytical calculations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW070

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPGW078

Change of Beam Distribution Due to Decoherence in the Presence of Transverse Feedback

feedback, simulation, octupole, damping

281

S.V. Furuseth, X. Buffat
CERN, Geneva, Switzerland
S.V. Furuseth
EPFL, Lausanne, Switzerland

The effect of Landau damping is often calculated based on a Gaussian beam distribution in all degrees of freedom. The stability of the beam is however strongly dependent on the details of the distribution. The present study focuses on the change of bunch distributions caused by the decoherence of the excitation driven by an external source of noise, in the presence of both amplitude detuning and a transverse feedback. Both multiparticle tracking simulations and theoretical models show a similar change of the distribution. The possible loss of Landau damping driven by this change is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW078

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paper received ※ 08 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPGW083

Longitudinal Coupled-Bunch Instability Evaluation for FCC-hh

impedance, cavity, HOM, synchrotron

297

I. Karpov, E.N. Shaposhnikova
CERN, Meyrin, Switzerland

High-order modes (HOM) of the accelerating rf structures and other machine elements, if not sufficiently damped, can drive longitudinal coupled-bunch instabilities (CBI). Their thresholds can be accurately obtained from macro-particle simulations using the detailed impedance model containing many different contributions. This method, however, is very difficult to apply for synchrotrons with a large number of bunches, as it is the case for the Future Circular hadron-hadron Collider (FCC-hh) with up to 10400 circulating bunches per beam. In this paper the semi-analytical approach is used for calculations of the instability thresholds during the acceleration cycle of the FCC-hh. As the result, we define requirements for the HOM damping that would be sufficient to prevent development of longitudinal CBI in the presence of weak synchrotron radiation damping.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW083

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW091

Capture and Flat-Bottom Losses in the CERN SPS

beam-loading, injection, impedance, feedback

327

M. Schwarz, A. Lasheen, G. Papotti, J. Repond, E.N. Shaposhnikova, H. Timko
CERN, Meyrin, Switzerland

Particle losses on the flat bottom of the SPS, the last accelerator in the injector chain of the LHC at CERN, are a strong limitation for reaching the high intensities required by the high luminosity upgrade of the LHC. Two contributions to these losses are investigated in this paper. The first losses occur during the PS-to-SPS bunch-to-bucket transfer, since the bunch rotation in the PS creates halo particles and the bunch does not completely fit into the SPS RF-bucket. The effect of longitudinal shaving in the PS on the beam transmission was recently tested. At high intensities, further capture losses are caused by beam loading in the traveling wave RF system of the SPS, which is partially compensated by the LLRF system, in particular by one-turn delay feedback. While the feedforward system reduces the capture losses, it also increases the losses along the flat bottom due to the RF noise.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW091

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paper received ※ 09 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPGW092

Design Status of DESY IV – Booster Upgrade for PETRA IV

booster, injection, insertion, linac

331

H.C. Chao
DESY, Hamburg, Germany

In PETRA IV project the on-axis injection scheme is preferred since there is no sufficient dynamic aperture for off-axis injection in ultra low emittance storage rings. The challenge is to prepare the injected bunches with the smaller emittance and larger intensity. The current injector complex including the accumulator and booster does not fulfill the requirements and thus will need refurbishments. The injector upgrade option chosen will be composed of an upgraded electron gun, a higher energy LINAC, and the new booster synchrotron DESY IV which has smaller emittance. DESY IV will be located in the existing tunnel of the current booster DESY II. The design of the lattice and some simulation results are addressed in this article.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW092

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paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW096

Beam Dynamics in MBA Lattices with Different Chromaticity Correction Schemes

lattice, sextupole, betatron, storage-ring

346

L. Hoummi, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L. Hoummi, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Loulergue, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

Ultra-low emittance lattices are being studied for the future upgrade of the 2.75 GeV SOLEIL storage ring. The candidate baseline lattice was inspired by the ESRF-EBS-type Multi-Bend-Achromat (MBA) lattice, introducing a (-I) transformation to compensate the nonlinear impact of sextupoles thanks to the lattice symmetry and tight control of the betatron phase advance between sextupoles. Whilst the final performance is still being optimized, other types of lattices are being considered for SOLEIL: This includes the so-called High-Order Achromat (HOA) lattice. Though the (-I) scheme provides a large on-momentum transverse dynamic aperture in 4D, its off-momentum performance is rather limited. 6D studies reveal intrinsic off-momentum transverse oscillations which are likely to result from a nonlinear increase in path length. This contribution presents the effects from the inhomogeneous sextupole distribution in the (-I) scheme and compares them with the HOA lattice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW096

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW111

Start to End Simulation on Beam Dynamics in Coherent Electron Cooling Accelerator

electron, FEL, bunching, cavity

379

Y.C. Jing, V. Litvinenko, I. Petrushina, I. Pinayev, K. Shih, Y.H. Wu
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA
K. Shih
SBU, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A Coherent electron Cooling (CeC) has a potential of substantial reducing cooling time of the high-energy hadrons and hence to boost luminosity in high-intensity hadron-hadron and electron-hadron colliders. In a CeC system, a high quality electron beam is generated, propagated and optimized through a beam line which was carefully designed with consideration of space charge effect, wakefields and nonlinear dynamics such as coherent synchrotron radiation and chromatic aberration. In this paper, we present our study on the beam dynamics of such a beam line and compare the simulation result with what was measured in experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW111

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paper received ※ 17 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW112

Design of a Bunch Compressor with CSR Suppression to Achieve Hundreds of kA Peak Current

electron, optics, site, dipole

382

Y.C. Jing, V. Litvinenko
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A four dipole magnetic chicane is usually used to compress electron bunch to very short in modern accelerators which requires electron beams to have high peak current. The coherent synchrotron radiation (CSR) originated from the strong bending magnets in the chicane could greatly degrade the quality of the electron beam. In this paper, we present our design for a bunch compressing system with 30 to 100 fold in bunch length reduction and at the mean time suppress the effect of CSR on the e-beam’s quality. We discuss and detail the performance of such a compressor for potential FACET-II upgrade.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW112

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW115

A Cross-Cell Interleaved Nonlinear Lattice for Potential NSLS-II Upgrade

lattice, sextupole, optics, dynamic-aperture

393

Y. Li, A. He, B.N. Kosciuk, T.V. Shaftan, V.V. Smaluk
BNL, Upton, Long Island, New York, USA
Z.H. Bai, L. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

An interleaved sextupole scheme using cross-cell betatron phase cancellation technique is adopted as a candidate for the future NSLS-II upgrade lattice. The lattice uses as many NSLS-II installed magnets as possible, including 30 dipoles, to compose a triple bend achromat lattice. A 300 pm.rad horizontal beam emittance is achieved. The emittance can be further reduced to around 200 pm rad with damping wigglers. Various design concepts used in modern 4th-generation light sources, such as adopting longitudinal gradient dipoles and anti-bend scheme, are incorporated into the design as well. The betatron phase-advance between sextupoles is designed to have a cross-cell interleaving cancellation pattern in the transverse planes. The dynamic aperture is big enough for the conventional off-axis top-off injection. At the same time, a large energy acceptance looks promising to ensure a sufficiently long beam lifetime.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW115

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paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP002

Linac and Damping Ring Designs for the FCC-ee

linac, positron, gun, electron

420

S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
I. Chaikovska, R. Chehab
LAL, Orsay, France
K. Furukawa, N. Iida, T. Kamitani, F. Miyahara, K. Oide
KEK, Ibaraki, Japan
E.V. Ozcan
Bogazici University, Bebek / Istanbul, Turkey
S.M. Polozov
MEPhI, Moscow, Russia
L. Rinolfi
ESI, Archamps, France
F. Yaman
IZTECH, Izmir, Turkey

We report the design of the pre-injector chain for the Future Circular e⁺ e⁻ Collider (FCC-ee) system. The electron beam from a low-emittance RF gun is accelerated by an S-band linac up to 6 GeV. A damping ring at 1.54 GeV is required for emittance cooling of the positron beam. The intermediate energy step from the exit of the S-band linac at 6 GeV to the 20 GeV injection energy of the top-up booster can be provided by the modified Super Proton Synchrotron (SPS), serving as a pre-booster ring (PBR). An alternative option to reach 20 GeV energy would be to extend the S-band linac with a C- or X-band linac. An overall cost optimisation will determine the choice of the final configuration. Beam loss and emittance dilution in the linac due to space charge effects, wakefields, and misalignment of accelerator components can be mitigated by RF phasing and orbit steering. Start-to-end simulations examine the beam transport through the linac up to either 6 GeV or 20 GeV. The results indicate large design margins. Simulations of the beam dynamics in the damping ring (DR) demonstrate a sufficiently large momentum acceptance. Effects of intrabeam scattering and electron cloud instability in the DR are also studied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP002

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPMP009

Effect of Initial Parameters on the Super Flat Beam Generation with the Phase-Space Rotation for Linear Colliders

simulation, gun, collider, solenoid

442

M. Kuriki, R. Tamura
HU/AdSM, Higashi-Hiroshima, Japan
H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J.G. Power
ANL, Argonne, Illinois, USA
K. Sakaue
The University of Tokyo, The School of Engineering, Tokyo, Japan
M. Washio
RISE, Tokyo, Japan

Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI) Kiban B.
Linear collider is a concept to realize e⁺e⁻ collision beyond the limitation of the ring colliders by the synchrotron radiation. To obtain an enough luminosity, eg. 1.0·10⁺³⁴ cm^-2sec^-1, the beam is focused down to nano-meter size with a high aspect ratio. This super flat beam is useful to improve the luminosity and to compensate the beam-beam effect, eg. Beamstrahlung. In a conventional design, the super-flat beam is produced by radiation damping in a storage ring. We propose to produce this super-flat beam with phase-space rotation techniques. We employ both Round to Flat Beam Transformation and Transverse to Longitudinal Emittance eXchange, the super flat beam can be generated by controlling the space-charge effect which spoiled the performance. We present the RFBT performance with respect to the initial conditions, i.e. beam size, initial emittance, solenoid field (strength and profile), etc.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP009

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP016

Intra-Bunch Energy Spread Minimisation for CLIC Operation at a Centre-of-Mass Energy of 350 GeV

linac, luminosity, collider, linear-collider

458

N. Blaskovic Kraljevic, D. Arominski, D. Schulte
CERN, Meyrin, Switzerland

The first stage of the electron-positron Compact Linear Collider (CLIC) is designed with a centre-of-mass energy of 380 GeV. A dedicated threshold scan in the vicinity of 350 GeV is envisioned with a total integrated luminosity of 100 fb^-1. This scan calls for a very small intra-bunch energy spread in order to achieve an excellent collision energy resolution. This paper presents an optimised assignment of RF accelerating gradients and phases in the CLIC main linac for operation at 350 GeV, which minimises the energy spread at the end of the main linac whilst preserving a small emittance growth. Variation of the bunch length and charge is studied in order to further reduce the energy spread; the effect on both the peak and total luminosity is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP016

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP017

Beam Orbit Correction in the CLIC Main Linac Using a Small Subset of Correctors

linac, quadrupole, collider, ground-motion

461

N. Blaskovic Kraljevic, D. Schulte
CERN, Meyrin, Switzerland

Beam orbit correction in future linear colliders, such as the Compact Linear Collider (CLIC), is essential to mitigate the effect of accelerator element misalignment due to ground motion. The correction is performed using correctors distributed along the accelerator, based on the beam position monitor (BPM) readout from the preceding bunch train, with a train repetition frequency of 50 Hz. This paper presents the use of the MICADO algorithm* to select a subset of N ~ 10 correctors (from a total of 576) to be used for orbit correction in the designed 380 GeV centre-of-mass energy first-stage of CLIC. The optimisation of the number N of correctors, the algorithm’s gain and the corrector step size is described, and the impact of a number of BPMs and correctors becoming unavailable is addressed. The application of a MICADO algorithm to perform dispersion free steering, by reducing the beam orbit difference between two beams with different energies, is discussed.
* B. Autin & Y. Marti, "Closed orbit correction of A.G. machines using a small number of magnets", CERN-ISR-MA/73-17, 1973.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP017

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP018

Beam-Based Beamline Element Alignment for the Main Linac of the 380 GeV Stage of CLIC

linac, alignment, collider, wakefield

465

N. Blaskovic Kraljevic, D. Schulte
CERN, Meyrin, Switzerland

The extremely small vertical beam size required at the interaction point of future linear colliders, such as the Compact Linear Collider (CLIC), calls for a very small vertical emittance. The strong wakefields in the high frequency 12 GHz CLIC accelerating structures set tight tolerances on the alignment of the main linac’s beamline elements and on the correction of the beam orbit through them in order to mantain a small emittance growth. This paper presents the emittance growth due to each type of beamline element misalignment in the designed 380 GeV centre-of-mass energy first-stage of CLIC, and the emittance growth following a series of beam-based alignment (BBA) procedures. The BBA techniques used are one-to-one steering, followed by dispersion free steering and finally accelerating structure alignment using wakefield monitors.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP018

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP025

Moving Long-range Beam-beam Encounters in Heavy-ion Colliders

proton, injection, collider, acceleration

488

M.A. Jebramcik, J.M. Jowett
CERN, Geneva, Switzerland

Asymmetric ion beam collisions like proton-lead in the LHC or gold-deuteron in RHIC have become major components of heavy-ion physics programmes. The injection and ramp of two different ion species with the same magnetic rigidity and consequently unequal revolution frequencies generate moving long-range beam-beam encounters in the interactions regions of the collider. These encounters led to fast beam losses and can cause emittance blow-up as observed in RHIC in the early 2000s and, more recently, in 2015. Yet such effects are absent at the LHC so the difference between the two colliders requires explanation. Tools and models have been developed to describe the beam dynamics of moving long-range beam-beam encounters and to predict the evolution of emittance and other beam parameters. Besides presenting results for RHIC and the LHC we give an outlook for the HL-LHC and potential operational restrictions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP025

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paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPMP031

Operation and Performance of the Cern Large Hadron Collider During Proton Run 2

luminosity, operation, proton, injection

504

R. Steerenberg, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, G.E. Crockford, J.-C. Dumont, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Lamont, E. Métral, D. Nisbet, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, M. Schaumann, M. Solfaroli, R. Suykerbuyk, G. Trad, J.A. Uythoven, S. Uznanski, D.J. Walsh, J. Wenninger, M. Zerlauth
CERN, Geneva, Switzerland

Run 2 of the CERN Large Hadron Collider (LHC) was successfully completed on 10th December 2018, achieving largely all goals set in terms of luminosity production. Following the first two-year long shutdown and the re-commissioning in 2015 at 6.5 TeV, the beam performance was increased to reach a peak luminosity of more than twice the design value and a colliding beam time ratio of 50%. This was accomplished thanks to the increased beam brightness from the injector chain, the high machine availability and the performance enhancements made in the LHC for which some methods and tools, foreseen for the High Luminosity LHC (HL-LHC) were tested and deployed operationally. This contribution provides an overview of the operational aspects, main limitations and achievements for the proton Run 2.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP031

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paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPMP035

Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider

luminosity, collider, radiation, photon

516

M.A. Valdivia García, F. Zimmermann
CERN, Meyrin, Switzerland

Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035

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paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPMP037

Updated High-Energy LHC Design

injection, proton, impedance, damping

524

F. Zimmermann, D. Amorim, S.A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, J. Keintzel, R. Kersevan, V. Mertens, J. Molson, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann
CERN, Geneva, Switzerland
J.L. Abelleira, A. Abramov, E. Cruz Alaniz, H. Pikhartova, A. Seryi, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
A. Apyan
ANSL, Yerevan, Armenia
J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco
EPFL, Lausanne, Switzerland
F. Burkart
DESY, Hamburg, Germany
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
G. Guillermo Cantón
CINVESTAV, Mérida, Mexico
K. Ohmi, K. Oide, D. Zhou
KEK, Ibaraki, Japan

Funding: This work was supported in part by the European Commission under the HORIZON 2020 project ARIES no.730871, and by the Swiss Accelerator Research and Technology collaboration CHART.
We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb₃Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP037

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB001

Low Emittance Tuning of FCC-ee

coupling, lattice, quadrupole, sextupole

574

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
S. Aumon, B.J. Holzer, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001

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paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPRB003

Multi-Target Lattice for Muon Production From e⁺ Beam Annihilation on Target

target, positron, lattice, site

578

O.R. Blanco-García
LAL, Orsay, France
M. Antonelli, M.E. Biagini, M. Boscolo, A. Ciarma, S. Guiducci, C. Vaccarezza, A. Variola
INFN/LNF, Frascati, Italy
G. Cesarini
INFN-Roma, Roma, Italy
F. Collamati
INFN-Roma1, Rome, Italy
R. Li Voti
Sapienza University of Rome, Rome, Italy
P. Raimondi
ESRF, Grenoble, France

The Low Emittance Muon Accelerator~(LEMMA) aims at producing small emittance muons from positron annihilation with electrons in a target. Given the low cross section of the production process, a large number of positrons on the target are required, exposing it to high power deposition and the beam to large degradation because of multiple scattering and bremstrahlung. A multi-target IP, and multi-IP line has been studied to reduce the power deposition per target and the degradation of the positron beam while preserving the number of muon pairs produced. The lattice copes with the focusing and transport of three beams at two different energies, the positron beam at 45 GeV, and µ⁺+ and µ⁻ beams at 22.5~GeV. Studies on the beam dynamics, number of targets, material and thickness of the targets are reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB003

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB011

Progress on Muon Ionization Cooling Demonstration with MICE

simulation, experiment, detector, framework

594

C. Hunt
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy
C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom

Funding: STFC, NSF, DOE, INFN, CHIPP andd more
The Muon Ionization Cooling Experiment (MICE) at RAL has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. Further studies are providing now more and deeper insight.
Submitted by the chair of our MICE speakers bureau.
If accepted, a member of the collaboration will soon be identified to present the contribution and will register immediately after.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB011

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB012

RECENT RESULTS FROM MICE ON MULTIPLE COULOMB SCATTERING AND ENERGY LOSS

scattering, detector, framework, acceleration

598

C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom
J.C. Nugent
University of Glasgow, Glasgow, United Kingdom

Funding: STFC, NSF, DOE, INFN, CHIPP and more
Multiple Coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, it is known that the simulation code (GEANT4) available at the time overestimated the scattering of muons in low Z materials. Updates to GEANT4 have brought the simulations in line with the MuScat data and these new models can be validated over a larger range of momentum, 170-250 MeV/c, with MICE data. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in the spring of 2016 using a lithium hydride absorber and in the fall of 2017 using a liquid hydrogen absorber. The measurement in lithium hydride is reported here along with the preliminary measurements in liquid hydrogen. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are all compared with the Bethe-Bloch formula and with the predictions of various models, including the default GEANT4 model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB012

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPRB013

Focusing of High-Brightness Electron Beams with Active-Plasma Lenses

plasma, focusing, electron, experiment

601

R. Pompili
INFN/LNF, Frascati, Italy

Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB013

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB023

Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam

rfq, experiment, polarization, acceleration

622

H.Y. Yasuda
University of Tokyo, Tokyo, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
N. Kawamura, T. Mibe, M. Otani
KEK, Ibaraki, Japan
Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan

Funding: This work was supported by JSPS KAKENHI Grant Numbers JP18J22129, JP18H03707.
Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB023

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB062

nuSTORM Decay Ring

lattice, quadrupole, resonance, closed-orbit

716

J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
R.B. Appleby, S.C. Tygier
UMAN, Manchester, 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

Precise neutrino cross section measurements and search for sterile neutrinos can be done with neutrino beams produced from muons decaying in a storage ring due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam would be captured. The storage ring has three options: a FODO solution with large aperture quadrupoles, a racetrack FFA (Fixed Field Alternating gradient) using the recent developments in FFAs and a hybrid solution of the two previous options. Machine parameters, linear optics design and beam dynamics of the hybrid solution are discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB062

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB077

Results From the CBETA Fractional Arc Test

linac, cavity, MMI, betatron

751

C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA

We report on commissioning experiments of the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. The beam from the injector is accelerated by a linac with a 36 MeV design energy gain, is transported through a splitter line that uses conventional magnets, and finally into a four cell permanent magnet based fixed field alternating (FFA) gradient arc. We measure beam properties in the injector, calibrate the energy gain and phase of the linac cavities using time of flight to a BPM at the end of the linac. We scan individual cavity phases and pass beam through the cavities to determine the transverse offset of the individual cavities. We scan the beam position in the splitter BPMs to estimate and correct the nonlinearity in the BPM response. We tested our path length adjustment mechanism. We measure the dispersion and R56 in the FFA arc.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB077

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB090

Simulation Challenges for eRHIC Beam-Beam Study

electron, proton, simulation, damping

785

Y. Luo, F.J. Willeke
BNL, Upton, Long Island, New York, USA
Y. Hao
FRIB, East Lansing, Michigan, USA
J. Qiang
LBNL, Berkeley, California, USA
Y. Roblin, H. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 2015 Nuclear Science Advisory Committee Long Rang Plan identified the need for an electron-ion collider (EIC) facility as a gluon microscope with capabilities beyond those of any existing accelerator complex. To reach the required high energy, high luminosity, and high polarization, the eRHIC design, based on the existing heavy ion and polarized proton collider RHIC, adopts a very small \beta-function at the interaction points, a high collision repetition rate, and a novel hadron cooling scheme. A full crossing angle of 22 mrad and crab cavities for both electron and proton rings are required. In this article, we will present the high priority R\&D items related to the beam-beam interaction studies for the current eRHIC design, the simulation challenges, and our plans and methods to address them. Recent progresses on this project are reported too.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB090

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB105

Measurement and Analysis of Beam Phase-space Distributions for the Fermilab Muon Campus accelerator complex

quadrupole, framework, experiment, simulation

810

A. Ramirez
University of Houston, Houston, Texas, USA
D. Stratakis
Fermilab, Batavia, Illinois, USA

The Muon g-2 experiment at Fermilab is tasked with measuring the muon’s anomalous magnetic moment with high precision. Since the experiment requires large amounts of muons, it is imperative to systematically study the behavior of the beam along the transport line. Unfortunately, the available diagnostics only provide beam information in X-Y space. For a complete evaluation, information of the phase-space is required. This paper demonstrates a technique to measure the beam phase-space distribution by using a set of beam profiles. First, we establish the theoretical framework that describes the principle of the technique. Next, we apply the technique at four different locations along the accelerator delivery line. Finally, we compare our findings to predictions from tracking simulations. Our results indicate that the beam phase-space volume is conserved, along the beam delivery line, suggesting minimal loses and linear transport as expected by design. Compared to the simulations, there is good agreement in both horizontal and vertical plane with the former being at the 4% level while the latter being in the 15% level. Our proposed technique is expected to provide a promising approach for optimizing injection and thereby improving the performance of the Muon g-2 Experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB105

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB110

Simulation Study of the Emittance Measurements in Magnetized Electron Beam

solenoid, cathode, electron, gun

822

S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft
ODU, Norfolk, Virginia, USA
J.F. Benesch, F.E. Hannon, G.A. Krafft, M.A. Mamun, G.G. Palacios Serrano, M. Poelker, R. Suleiman, S. Zhang
JLab, Newport News, Virginia, USA

Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177
Electron cooling of the ion beam is key to obtaining the required high luminosity of proposed electron-ion colliders. For the Jefferson Lab Electron Ion Collider, the expected luminosity of 10³⁴ 〖 cm〗^-2 s^-1 will be achieved through so-called ’magnetized electron cooling’, where the cooling process occurs inside a solenoid field, which will be part of the collider ring and facilitated using a circulator ring and Energy Recovery Linac (ERL). As an initial step, we generated magnetized electron beam using a new compact DC high voltage photogun biased at -300 kV employing an alkali-antimonide photocathode. This contribution presents the characterization of the magnetized electron beam (emittance variations with the magnetic field strength for different laser spot sizes) and a comparison to GPT simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB110

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB116

Laser Sculpted Cool Proton Beams

laser, linac, proton, simulation

826

S.M. Gibson, L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
S.E. Alden, S.M. Gibson, L.J. Nevay
JAI, Egham, Surrey, United Kingdom

Funding: We acknowledge support by STFC grant ST/P003028/1
Hydrogen ion accelerators, such as CERN’s Linac4, are increasingly used as the front end of high power proton drivers for high energy physics, spallation neutron sources and other applications. Typically, a foil strips the hydrogen ion beam to facilitate charge-exchange injection of protons into orbits of high energy accelerators, in which the resulting emittance is dominated by phase-space painting. In this paper, a new method to laser extract a narrow beam of neutralised hydrogen from the parent H⁻ ion beam is proposed. Subsequent foil stripping and capture of protons into a storage ring generates cool proton bunches with significantly reduced emittance compared to the parent beam. The properties of the extracted proton beam can be precisely controlled and sculpted by adjusting the optical parameters of the laser beam. Recirculation of the parent beam allows time for space-charge effects to repopulate the emittance phase space prior to repeated laser extraction. We present particle tracking simulations of the proposed scheme, including the laser-particle interaction with realistic optical parameters and show the resulting emittance is reduced. Developments for an experimental demonstration of a laser controlled particle beam are outlined. In principle, the proposed scheme could considerably reduce the emittance of protons bunches injected into an accelerator, such as the LHC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB116

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paper received ※ 16 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS003

Superconducting LINAC Design Upgrade in View of the 100 MeV MYRRHA Phase I

linac, cavity, cryomodule, lattice

837

F. Bouly, M.A. Baylac
LPSC, Grenoble Cedex, France
A. Gatera
SCK•CEN, Mol, Belgium
D. Uriot
CEA-DRF-IRFU, France

Funding: Part of this work supported by the European Atomic Energy Community (EURATOM) H₂020 Programme under grant agreement n°662186 (MYRTE project).
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 Belgium government the project has entered in its phase I: which consists in the development and the construction of the linac first part, up to 100 MeV. We review the design updates of the superconducting linac, with its enhanced fault-tolerance capabilities. The linac capabilities at 100 MeV (Phase I) and 600 MeV (ADS operation) are exposed and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS003

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paper received ※ 23 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS006

Final Results of the SPIRAL2 Injector Commissioning

rfq, LEBT, MMI, linac

848

R. Ferdinand, M. Di Giacomo, H. Franberg, J.-M. Lagniel, G. Normand, A. Savalle
GANIL, Caen, France
D. Uriot
CEA-DRF-IRFU, France

The SPIRAL2 injector, made up of a 5 mA p-d ion source, a 1 mA heavy ion source (up to A/Q = 3) and a CW 0.75 MeV/u RFQ, has been commissioned in parallel with the superconducting linac installation. This com-missioning is successfully completed now and the Diag-nostic plate (D-plate) used to characterize the injector beams is removed. This paper presents the results ob-tained with the reference particles (H⁺, 4He2+, 18O6+ and 40Ar14+) and a comparison with the simulations. The connexion to the SC linac and the future linac beam commissioning is briefly described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS006

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paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS032

New Beam Dynamics Simulations for the FAIR p-Linac RFQ

rfq, simulation, linac, LEBT

921

M. Syha, H. Hähnel, U. Ratzinger, M. Schuett
IAP, Frankfurt am Main, Germany

The construction of a 3.3m Ladder-RFQ at IAP*, Goethe University Frankfurt, has been finished successfully last summer. This RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-Linac at FAIR**. Along the acceleration section the parameters modulation, aperture and synchronous phase are varied linearly with cell number, which differs from former designs from IAP Frankfurt. The ratio of transversal vane curvature radius to mid-cell radial aperture and the vane radius itself are constant. The development of an adequate beam dynamics design was done with the aid of the RFQGen-code and in close collaboration with the IAP resonator design team. The RFQ beam dynamics design could be successfully reproduced with the TOUTATIS-routine of CEAs*** TraceWin-code. Several new beam dynamics simulations were performed on the design. Among these were current and Twiss parameter studies as well as simulations concerned with the investigation of longitudinal entrance and exit gap field effects. Others were based on new measurements in the LEBT-line performed by the GSI**** Ion Source Group in April 2019. In the near future, further LEBT measurements and subsequent simulations (among other to design a well-fitting cone for the RFQ), as well as mechanical error studies in TOUTATIS, will follow.
*Institute of Applied Physics
**Facility for Antiproton and Ion Research
***French Alternative Energies and Atomic Energy Commission
****GSI Helmholtz Centre for Heavy Ion Research

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS032

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS067

The Progress in Physics Design of HEPS LINAC

linac, wakefield, bunching, electron

1008

C. Meng, D.Y. He, X. He, J.Y. Li, Y.M. Peng, S.C. Wang, O. Xiao, J.R. Zhang, S.P. Zhang
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance light source to be built in China. The injector is composed of a 500-MeV Linac and a full energy booster. According to the study and com-missioning consideration of on-axis swap-out injec-tion system, a high bunch charge injector is desirable and a Linac that can provide 7nC per bunch electron beam to booster is needed. This paper present different bunching system schemes and the performance of different schemes are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS067

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paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPTS073

Bunching System Optimization Based on MOGA

bunching, linac, electron, solenoid

1018

S.P. Zhang, J.Y. Li, C. Meng
IHEP, Beijing, People’s Republic of China

Multiobjective Genetic Algorithms (MOGA) is effective in dealing with optimization problems with multiple objectives. The bunching system of the High Energy Photon Source (HEPS) linac adopts a traditional bunching system for compressing electron beams with a pulse charge of 4 nC. The bunching system is optimized using MOGA. The optimization include minimizing the normalized emittance and maximizing transmission efficiency. The optimization results have reached the design target, and are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS073

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS083

Beam Dynamics Simulation with an Updated Model for the ESS Ion Source and Low Energy Beam Transport

LEBT, rfq, solenoid, simulation

1042

E. Nilsson, M. Eshraqi, J.F. Esteban Müller, Y. Levinsen, N. Milas, R. Miyamoto
ESS, Lund, Sweden

Beam dynamics simulation of the ion source (IS) and low energy beam transport (LEBT) of the European Spallation Source (ESS) Linac is conducted with TraceWin and IBSimu code. TraceWin allows multi-particle tracking based on a particle-in-cell space-charge solver and is the standard simulation tool of the whole ESS Linac. IBSimu is based on a Vlasov solver and allows to simulate beam extraction from plasma as well as the beam transport in the LEBT. In preparation for beam commissioning of the IS and LEBT in the ESS Linac tunnel, which started in September 2018 and is ongoing as of the timing of writing this paper, the simulation models of the IS and LEBT in these two codes were updated. This paper reports the effort for these updates, including the beam distribution out of the IS, electromagnetic field map of the LEBT solenoid, more realistic aperture structure in the LEBT, as well as updated LEBT solenoids scan simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS083

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paper received ※ 17 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPTS084

ESS Low Energy Beam Transport Tuning During the First Beam Commissioning Stage

solenoid, LEBT, MMI, rfq

1046

R. Miyamoto, C.S. Derrez, E. Laface, Y. Levinsen, N. Milas, A.G. Sosa, R. Tarkeshian, C.A. Thomas
ESS, Lund, Sweden

Beam commissioning of the ion source (IS) and low energy beam transport (LEBT) of the European Spallation Source is ongoing on its site as of writing this paper and continues until June 2019. The LEBT consists of two solenoids with integrated dipole correctors to steer, focus, and match the high current divergent beam out of the IS to the following radio frequency quadrupole (RFQ). It is also equipped with a suite of diagnostics devices to provide a full characterization of the beam for achieving a good transport within the LEBT, optimizing the matching to the RFQ, and also providing references to numerical simulations. This paper presents results of beam characterization campaign from the ongoing beam commissioning period, including the matching at the RFQ interface based on emittance sampling for varied strengths of the solenoids and verification of the linear model for the trajectory and beam envelope.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS084

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paper received ※ 21 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPTS086

Identification and Compensation of Betatronic Resonances in the Proton Synchrotron Booster at 160 Mev

resonance, space-charge, injection, proton

1054

A. Santamaría García, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, G.P. Di Giovanni, B. Mikulec
CERN, Geneva, Switzerland
F. Asvesta
NTUA, Athens, Greece
H. Rafique
University of Manchester, Manchester, United Kingdom

The Proton Synchrotron Booster (PSB) is the first circular accelerator in the injector chain to the Large Hadron Collider (LHC) and accelerates protons from 50 MeV to 1.4 GeV. The PSB will need to deliver two times the current brightness after the LHC Injectors Upgrade (LIU) in order to meet the High Luminosity LHC (HL-LHC) beam requirements. At the current injection energy a large incoherent space charge tune spread limits the brightness of the beams, which is one of the main motivations to increase the injection energy to 160 MeV with the injection provided by Linac4, a new H⁻ linear accelerator. The higher injection energy will allow doubling the beam intensity while maintaining a space charge tune spread similar to current values. The degradation of the beam brightness due to the tune spread can be minimized with a proper choice of working point and an efficient compensation of resonances. In this paper, we present the measurement of the betatronic resonances in the four rings of the PSB at 160 MeV before the Long Shutdown 2, as well as the results of a proposed compensation scheme.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS086

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS087

Transverse Emittance Studies at Extraction of the CERN PS Booster

optics, operation, booster, injection

1058

F. Antoniou, S.C.P. Albright, F. Asvesta, H. Bartosik, G.P. Di Giovanni, V. Forte, M.A. Fraser, A. Garcia-Tabares, A. Huschauer, B. Mikulec, T. Prebibaj, A. Santamaría García, P.K. Skowroński
CERN, Meyrin, Switzerland
F. Asvesta
NTUA, Athens, Greece
T. Prebibaj
National Technical University of Athens, Zografou, Greece

Transverse emittance discrepancy in the beam transfer between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is observed in operational conditions for the LHC beams at CERN. The ongoing LHC Injectors Upgrade (LIU) project requires a tight budget for beam degradation along the injector chain and therefore the reason for this emittance discrepancy needs to be understood. Systematic measurements have been performed for various beam characteristics (beam intensity, transverse and longitudinal emittance). In this paper, a comparison between the emittance measurements using all available beam instrumentation with different emittance computation algorithms is presented. The results are compared to measurements at PS injection. Furthermore, the impact on the LIU project requirements for the emittance preservation along the LHC Injectors Complex is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS087

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPTS089

Transverse Beam Dynamics Studies With High Intensity LHC Beams in the SPS

injection, octupole, impedance, electron

1062

M. Carlà, H. Bartosik, M.S. Beck, L.R. Carver, V. Kain, G. Kotzian, K.S.B. Li, G. Rumolo, C. Zannini
CERN, Geneva, Switzerland

In order to reach the target beam parameters of the LHC injectors upgrade (LIU), about twice the presently operational intensity of LHC type beams has to be achieved. Although the planned upgrade of the main RF system will occur during the long shutdown, a series of measurements have been performed to assess the beam dynamics challenges with these very high intensity beams on the long SPS injection plateau. Bunch-by-bunch transverse emittance blow-up measurements suggested the presence of electron-cloud. After a period of running with the high intensity beam for a couple of days, a clear improvement of beam quality was observed which is attributed to scrubbing. In addition, a horizontal headtail instability is encountered for the usual operational settings of chromaticity and transverse damper. The stability limit as a function of chromaticity and Landau octupole settings has been explored and will be discussed, together with possible sources of the instability and mitigation strategies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS089

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paper received ※ 06 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPTS096

Linac4: Reliability Run Results and Source Extraction Studies

extraction, linac, simulation, plasma

1090

D. Noll, G. Bellodi, S.B. Bertolo, F.D.L. Di Lorenzo, J.-B. Lallement, J. Lettry, A.M. Lombardi, C.M. Mastrostefano, B. Mikulec, M. O’Neil, S. Schuh, R. Wegner
CERN, Meyrin, Switzerland

Linac4, a 160 MeV, 352.2 MHz linear accelerator, has been fully commissioned and will take its place as new injector to the CERN chain of accelerators during the long shutdown (LS2) in 2019-2020. In the past year, it has been continuously providing beam during a test run to assess its reliability in view of the connection to the LHC injector chain. The target reliability of more than 90% has been demonstrated during the accumulated nine months of run in 2017 and 2018. The beam quality at 160 MeV is suitable for producing all beams for the CERN physics program of today. Nevertheless, the limited peak current of 30mA might be a limitation for future high intensity programs. The bottleneck has been identified at the low energy end of the accelerator. In the meantime, beam extraction and low energy beam transport studies are ongoing at a dedicated test stand with the goal to reach beam currents from the pre-injector up to 45 mA. We will present the status of the modelling of the pre-injector and possible solutions to reach higher beam currents from the RFQ along with results from the reliability run.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS096

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paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPTS097

Updates on Alternative Pre-Booster Ring Design and Wiggler Magnet Considerations of SPS for the FCC e⁺e⁻ Injector

damping, wiggler, injection, extraction

1094

O. Etisken
Ankara University, Faculty of Sciences, Ankara, Turkey
F. Antoniou, Y. Papaphilippou, T. Tydecks
CERN, Meyrin, Switzerland
A.K. Çiftçi
Izmir University of Economics, Balçova/Izmir, Turkey

The Future Circular e⁺e⁻ Collider (FCC- e⁺e⁻) injector complex needs to produce and to transport a high-intensity e⁺e⁻ beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and designing a completely new ring. The purpose of this paper is to explore the needs and parameters of the existing SPS, to investigate wiggler magnet options for SPS, and provide an updated study of alternative accelerator ring design with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the parameters of both choices are established, including the optics design, layout update and considerations for non-linear dynamics optimization.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS097

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paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS098

A Primary Electron Beam Facility at CERN

linac, electron, injection, proton

1098

Y. Papaphilippou, R. Corsini, Y. Dutheil, L.R. Evans, B. Goddard, A. Grudiev, A. Latina, S. Stapnes
CERN, Meyrin, Switzerland
T.P.Å. Åkesson
Lund University, Department of Physics, Lund, Sweden

This paper describes the concept of a primary electron beam facility at CERN, to be used for dark gauge force and light dark matter searches. The electron beam is produced in three stages: A Linac accelerates electrons from a photo-cathode up to 3.5 GeV. This beam is injected into the Super Proton Synchrotron, SPS, and accelerated up to a maximum energy of 16 GeV. Finally, the accelerated beam is slowly extracted to an experiment, possibly followed by a fast dump of the remaining electrons to another beamline. The beam parameters are optimized using the requirements of the Light Dark Matter eXperiment, LDMX, as benchmark.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS098

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS100

Transverse Emittance Measurement in the CERN Proton Synchrotron in View of Beam Production for the High-Luminosity LHC

brightness, proton, optics, betatron

1106

E. Senes, J. Emery, V. Forte, M.A. Fraser, A. Guerrero, A. Huschauer, F. Roncarolo, J.L. Sirvent, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade project the improvements required to achieve the parameters of the future beams for the High-Luminosity LHC are being studied and implemented. In order to deliver high brightness beams, control over the beam intensity and emittance is fundamental. Therefore, a highly accurate and reliable transverse emittance measurement is essential. Presently at the CERN Proton Synchrotron, the only operationally available emittance monitors not impacting the facility beam production are the flying wire scanners used to measure the circulating beam profile. The wire scanners will be replaced with a new generation in the next two years and a prototype is already installed. The prototype has been commissioned with beams featuring a wide range of intensities and emittances. This paper evaluates the performance of the prototype with respect to the present system via beam-based measurements. The transverse emittance measurement is discussed, considering the different potential error contributions to the measurement, such as knowledge of the machine optics and the dispersive contribution to the beam size.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS100

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paper received ※ 02 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS101

Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation

simulation, proton, scattering, brightness

1110

A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis
CERN, Geneva, Switzerland
E. Senes
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS105

The High Brightness Photo-injector for THz CUR/VUV FEL at NSRRC

radiation, electron, quadrupole, linac

1125

A.P. Lee, M.C. Chou, H.P. Hsueh, J.-Y. Hwang, W.K. Lau
NSRRC, Hsinchu, Taiwan
P. Wang
NTHU, Hsinchu, Taiwan

A high brightness photo-injector has been build for THz coherent undulator radiation and VUV free electron laser test facility at NSRRC. In the first phase, the photo-injector was used to produce ultra-short electron bunches for THz CUR generation. The electron beam is generated form a photocathode rf gun followed by a solenoid for emittance compensation. Then A 5.2 m S-band linac accelerates the electron beam and compresses the beam by velocity bunching. Since the beam emittance will grow during the velocity bunching process, a solenoid system was installed to reduce the emmitance growth. Downstream the linac, a quadruple magnet was use for emittance measurement by quadruple scan method and the bunch length was measured by the coherent transition radiation. Finally, the ultra-short electron bunch with about few hundreds picoseconds passes through a U100 planer undulator can produce THz coherent undulator radiation. The instrument setup and results of measurement are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS105

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paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPTS112

Matrix Approach to Decouple Transverse-Coupled Beams

coupling, quadrupole, solenoid, DTL

1144

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

Funding: Work supported by the National Key Research and Development Program of China (grant number 2016YFC0105408).
Transverse emittances, especially vertical emittance, are strictly required in the synchrotrons with multi-loop injection. Transverse emittances easily grow up if transverse beam phase spaces are coupled. The growth of the transverse emittance can be restained by decoupling the beam phase spaces. Based on the transfer matrix calculation, it can be theoretically proved that the decoupling can be implemented for general situations. A minimum number of rotated quadrupoles required for decoupling is given. Two quadrupoles can decouple the beam and suppress its emittance growth to 1% in the coupling DTL case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS112

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paper received ※ 28 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS120

Commissioning of the New Experimental FODO Line at the SNS Beam Test Facility

rfq, MMI, simulation, optics

1164

A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, V. Tzoganis, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
Z.L. Zhang
UTK, Knoxville, Tennessee, USA

The SNS Beam Test Facility consists of a 2.5MeV proton accelerator and a beam line with various diagnostics for high intensity beam dynamics study. A FODO line consisting of 19 quadrupole magnets and a large dynamic range emittance monitor has been added recently. The new setup is design for experimental study of mechanisms of halo formation in mismatched high intensity beams. We present results of the new beam line commissioning with beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS120

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paper received ※ 07 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUYPLM1

XFEL Performance Achieved at PAL-XFEL

FEL, undulator, electron, photon

1182

H. Heo, M.-H. Cho, J.H. Han, H.-S. Kang, C. Kim, G. Kim, M.J. Kim, J.H. Ko, H.-S. Lee, C.-K. Min, I.H. Nam, K.-H. Park, C.H. Shim, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) successfully completed the commissioning of SASE and started user operation in late 2016. Since then, the facility has demonstrated excellent stability with very small timing jitter of about 20 fs, and commissioned the self-seeding system over a wide range of photon energies, etc. The talk will provide an overview of the last three years at the PAL-XFEL, including some detailed experimental results, as well as future prospects for the laboratory.

Slides TUYPLM1 [7.516 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM1

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paper received ※ 20 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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TUZPLM2

Optics Measurements at SuperKEKB Using Beam Based Calibration for BPM and BBA

quadrupole, optics, betatron, coupling

1198

H. Sugimoto, H. Koiso, K. Mori, A. Morita, Y. Ohnishi, M. Tejima
KEK, Ibaraki, Japan

The beam-based calibration(BBC) technique for Beam-Position-Monitor(BPM) is applied in order to establish reliable optics measurement. In the BBC, a response model between beam position, charge and output signals of the BPM electrodes are introduced to calibrate the relative gain of the BPM electrodes. The gains are adjusted by total squares fitting so that the model reproduces the measured BPM signals. The Beam-Based Alignment(BBA) is also performed to determine the magnetic center of a quadrupole. Using BBC and BBA, the performance of the BPM system and optics correction are successfully improved. This talk presents what we experienced during the beam commissioning focusing on beam optics measurement and some details on the beam-based calibration scheme for BPM system.

Slides TUZPLM2 [15.911 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLM2

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUZPLS2

Beam Dynamics Study in the HEPS Storage Ring

lattice, storage-ring, photon, brightness

1203

Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.

Slides TUZPLS2 [9.517 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP044

Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems

vacuum, impedance, photon, experiment

1347

G.Y. Hsiung
NSRRC, Hsinchu, Taiwan

Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW004

Cls 2.2: Ultra-Brilliant Round Beams Using Pseudo Longitudinal Gradient Bends

quadrupole, injection, lattice, coupling

1385

L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

A preliminary design for a new storage for the Canadian Light Source was presented at IPAC’18 (Dallin). More recently a reconfigured lattice was presented at the 6th DLSR workshop. This lattice employed large βy and small βx in the straights. This has several advantages including: increased transverse coherence and brighter beams at small coupling; round beams at small coupling; flatter βy through the straights; and possible off-axis vertical injection at small amplitudes. Most recently longitudinal gradients in the dipoles have been implemented. This has lead to the unit cell bends being replaced by a ’pseudo longitudinal gradient’ bend array: bend1-bend2-bend1. This results in smaller emittance with simple magnet designs while maintaining adequate dynamic aperture for off-axis injection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW004

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW009

THE ESRF FROM 1988 TO 2018, 30 YEARS OF INNOVATION AND OPERATION

operation, SRF, vacuum, injection

1400

J.-L. Revol, L. Farvacque, L. Hardy, P. Raimondi
ESRF, Grenoble, France

In 1988, eleven European countries joined forces to build the European Synchrotron Facility in Grenoble [France]. The ESRF was the first third-generation light source worldwide. After 30 years of innovation and user operation, the present storage ring was shut down to leave room for a new and brighter source. This paper describes the evolution of the facility from its origin to the Ex-tremely Bright Source (EBS). Firstly, the operational aspects including reliability and beam modes are consid-ered. This is followed by the presentation of the progress of lattice and the implementation of top-up. Finally, the development of the radio frequency and vacuum systems are discussed. To conclude, the lessons learned from 30 years operation are summarized, especially in view of EBS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW009

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW011

Status of the PETRA IV project

lattice, brightness, timing, synchrotron

1404

I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang
DESY, Hamburg, Germany

Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW012

Sensitivity Studies of the PETRA IV Lattice

alignment, simulation, site, resonance

1408

I.V. Agapov
DESY, Hamburg, Germany

As the machine with the smallest emittance among the planned fourth-generation hard x-ray synchrotron light sources, PETRA IV will have very demanding requirements on magnet alignment and stability. Several developments to address mechanical and beam-based stabilization have been started in connection to that. Here we summarize the alignment and field error tollerances resulting from startup and commissioning simulations of the main ring. Novel high level control tools will be required to assure smooth operation of the machine; progress in their development and beam test results at PETRA III will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW012

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW013

Tune and Chromaticity Optimization at Bessy II for the Transverse Resonant Island Bucket Optics

optics, simulation, photon, resonance

1411

F. Armborst, P. Goslawski, A. Jankowiak
HZB, Berlin, Germany

Funding: Federal Ministry of Education and Research
Transverse Resonant Island Buckets (TRIBs *) correspond to a second stable orbit, longitudinally winding around the core orbit in the transverse x-x^′-phasespace. The exploitation possibilities for stable TRIBs are under investigation at the third generation light source BESSY II in Berlin. The applicability for bunch separation is a main subject of these studies. Stable operation of TRIBs optics with a single or few bunches on the second orbit and a multibunch train on the main orbit has been shown **. Photons emitted on the second orbit are well separated from those of the main orbit at all beamlines. This provides the possibility of bunch separation by beamline adjustment for the timing community without significant impact on the average brightness for other users. Simulations based on linear optics from closed orbits (LOCO) and on nonlinear optics derived from the measured chromaticity and tune shift with action (TSWA) predict this separation well. Friendly user experiments in 2018 confirmed these results. The scheduled upgrade BESSY VSR *** features simultaneously stored long and short bunches. Then TRIBs optics would in principle enable the separation of the different bunches at every beamline offering unique possibilities to our users. Simulations and measurements aiming to investigate further possible optimization of the TRIBs optics are presented.
* F. Armborst, P. Goslawski et al, DOI: 10.18429/JACoW-IPAC2018-TUPML052
** P. Goslawski, F. Armborst et al. DOI: 10.18429/JACoW-IPAC2017-WEPIK057
*** A. Jankowiak et al., DOI: 10.5442/R0001

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPGW018

PETRA IV Study with Non-Interleaved Sextupole Scheme

sextupole, lattice, storage-ring, optics

1430

H.C. Chao, R. Brinkmann, X.N. Gavaldà
DESY, Hamburg, Germany

This study is an attempt to design PETRA IV storage ring, which is an upgrade from PETRA III toward diffraction-limit synchrotron light source, based on the non-interleaved sextupole scheme. The lattice is constructed by mixing different types of cells. There are two basic building blocks. The double minus identity (DMI) cell dedicated for the chromaticity correction with non-interleaved sextupoles is tightly built up, while the combined function FODO cell with dispersion suppressors provides straights with small beta functions ideally for undulators. In addition, the hybrid section including a 10-m long super insertion device (ID) is custom-made to adapt to DESY’s current site plan. The beam dynamic behaviors are simulated and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW018

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paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW028

Low Energy Beam Transport System for MESA

cavity, laser, experiment, solenoid

1461

C. Matejcek, K. Aulenbacher, S. Friederich
IKP, Mainz, Germany

An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. The present setup includes the chopper- and bunching system. The devices are of most importance in order to achieve sufficient bunch compression particularely at higher bunch charges and currents. With the circular deflecting cavity of the chopper system it is possible to measure the longitudinal dimension of the bunches upstream of the buncher whereas downstream the longitudinal size will be measured by Smith Purcell radiation. Based on experimental results obtained from this setup we will discuss the beam parameter and compare them with simulations of the beamline.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW028

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paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW029

The Injection System and the Injector Complex for PETRA IV

injection, kicker, gun, booster

1465

J.X. Zhang, I.V. Agapov, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, J. Keil, F. Obier, M. Schmitz, R. Wanzenberg
DESY, Hamburg, Germany

PETRA IV project is to upgrade PETRA III to a synchrotron radiation source with an ultra-low emittance. Due to the small dynamic aperture of the PETRA IV storage ring, a horizontal on-axis injection is prepared. In this paper, the preliminary study of the injection scheme is described. To meet the requirements of the on-axis injection, a plan of a new injector complex, including the Gun, the LINAC and the accumulator is shown in this paper. Several options are discussed in this paper, too.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW029

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW031

Elettra, Present and Future

dipole, operation, coupling, insertion-device

1468

E. Karantzoulis, A. Carniel, S. Krecic
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with the final version of the upcoming upgrade, the diffraction limited light source Elettra 2.0.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW031

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paper received ※ 16 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW035

A Highly Brilliant Compact 3 GeV Light Source Project in Japan

cavity, storage-ring, injection, linac

1478

N. Nishimori
National Institutes for Quantum and Radiological Science and Technology (QST), Sayo-cho, Japan
H. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan
T. Watanabe
JASRI/SPring-8, Hyogo, Japan

A highly brilliant compact 3 GeV light source project was proposed in Japan. The light source would be constructed in Sendai, north-east part of Japan. It provides brilliant soft X-ray beam to widely cover wavelengths ranging from EUV to hard X-ray in Japan together with SPring-8. The accelerator system is now mostly designed except for several linac components and so on. We have chosen a 4-bend achromat lattice to achieve a low emittance keeping a small circumference with a rather relaxed space issue. The number of cells is 16 and the ring circumference is about 350 m. Number of available beam lines are 26 including short straight sections for multi-pole wigglers. Horizontal emittance is expected to be around 1.1 nmrad, and the maximum brilliance may exceed 10²¹ at 1 - 3 keV region with a stored current of 400 mA. The designs of many components such as vacuum chambers, magnets and monitors are employed from those studied for SPring-8 upgrade project. A full energy injector linac equipped with a thermionic gun and C-band accelerating structures is employed to produce sufficiently low emittance beams for efficient beam injections. The C-band system is adopted from those developed for XFEL SACLA with some modifications. In the future, the injector would be upgraded as an electron driver for SXFEL. Details of the project and accelerator system will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW035

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPGW036

1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance

operation, cavity, linac, gun

1482

T. Obina, D.A. Arakawa, M. Egi, T. Furuya, K. Haga, K. Harada, T. Honda, Y. Honda, T. Honma, E. Kako, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, T. Konomi, H. Matsumura, T. Miura, T. Miyajima, S. Nagahashi, H. Nakai, N. Nakamura, K. Nakanishi, K.N. Nigorikawa, T. Nogami, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, M. Shimada, M. Tadano, T. Takahashi, R. Takai, O.A. Tanaka, Y. Tanimoto, T. Uchiyama, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai, M. Sawamura
QST, Tokai, Japan
N. Nishimori
National Institutes for Quantum and Radiological Science and Technology (QST), Sayo-cho, Japan

A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %.
* S. Sakanaka, et.al., Nucl. Instr. and Meth. A 877 (2017)197, https://doi.org/10.1016/j.nima.2017.08.051

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW036

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW040

Study of Seven-Bend Achromat Lattices with Interleaved Dispersion Bumps for HALS

lattice, storage-ring, octupole, linear-dynamics

1495

Z.H. Bai, W. Li, G. Liu, L. Wang, D.R. Xu, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Previously, we proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleav-ed dispersion bumps, which was then used to design a 7BA lattice for the Hefei Advanced Light Source (HALS) storage ring. Recently, such a 7BA lattice was further designed and optimized for the HALS by changing the number of lattice cells, scanning working point and employing octupoles. And two new HALS designs with such 7BA lattices have been made, one with 30 lattice cells and a natural emittance of 25 pm·rad and the other with 28 cells and 33 pm·rad. They had much better nonlinear dynamics perfor-mances than the previous design. The detailed study for these two HALS lattices will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW040

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paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPGW041

Super-Period Locally Symmetric Lattices for Designing Diffraction-Limited Storage Rings

lattice, storage-ring, sextupole, quadrupole

1498

Z.H. Bai, W. Li, G. Liu, L. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Y. Li
BNL, Upton, Long Island, New York, USA

To achieve better nonlinear dynamics performance for a diffraction-limited storage ring, previously we proposed a locally symmetric multi-bend-achromat (MBA) lattice concept, where beta functions are locally symmetric about two mirror planes of each lattice cell. To have both high-beta long straight sections for beam injection and low-beta ones for higher brightness of insertion device radiation, many storage ring light sources use super-period lattices. The locally symmetric MBA lattice can be naturally extended to the super-period case. In the super-period locally symmetric (SP-LS) lattice, many nonlinear dynamics effects can be effectively cancelled out within one super-period lattice cell, and also there are many knobs to be used for further nonlinear optimization. As examples, two SP-LS lattices have been designed towards diffraction-limited emittances.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW041

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paper received ※ 20 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW042

Study of the Intra-beam Scattering Effects in the HALS Storage Ring

damping, wiggler, storage-ring, lattice

1501

W. Li, Z.H. Bai, W. Li, D.R. Xu, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077).
The Hefei Advanced Light Source (HALS) is designed to be a dedicated 4th generation diffraction limited light source. In 2018, the baseline lattice of the HALS storage ring has been proposed, with an ultra-low natural emittance of about 25 pm-rad. The preliminary study of intra-beam scattering effects on the beam emittance growth in the HALS storage ring has been performed with this baseline lattice. Due to the limited synchrotron radiation in this storage ring, damping wigglers are expected in this storage ring to reduce the damping time and reduce the emittance. In this paper, we will present the simulation results of the IBS effects, estimated effectiveness of damping wiggler and the corresponding linear optics calibration of the perturbation due to insertion device, and finally the estimated Touschek lifetime will be shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW042

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW045

Lattice Design for the Reversible SSMB

radiation, electron, storage-ring, bunching

1507

C.L. Li
SINAP, Shanghai, People’s Republic of China
A. Chao
SLAC, Menlo Park, California, USA
C. Feng, B.C. Jiang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPGW054

Design of a Hybrid Seven-Bend-Achromat Lattice for a High-Energy Diffraction-Limited Storage Ring Using a New Optimization Method

lattice, linear-dynamics, optics, sextupole

1528

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Recently, we proposed a new optimization method, with nonlinear dynamics indicators considered in the linear optics design, for designing hybrid multi-bend-achromat (MBA) lattices. With this method, two hybrid MBA lattices for medium-low-energy diffraction limited storage rings (DLSRs) have been designed, showing remarkable effectiveness in improving nonlinear dynamic performance. In this paper, we will apply this optimization method to the design of a hybrid 7BA lattice for a 6 GeV DLSR with the same circumference as that of HEPS. In the design, the strengths and arrangement of magnets of this lattice also meet the engineering requirement for HEPS. The designed lattice has a natural emittance of 34 pm·rad. The nonlinear dynamic performance is satisfactory, with a dynamic aperture of about 6 mm and 3 mm in the horizontal and vertical directions, respectively, and a dynamic momentum aperture of larger than 5%, which also shows the power of our optimization method.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW054

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW055

Comparison of Optimization Methods for Hybrid Seven-Bend-Achromat Lattice Design

lattice, linear-dynamics, sextupole, optics

1532

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Generally, for a hybrid multi-bend-achromat (MBA) lattice with fixed linear optics, there is little potential to further optimize the nonlinear dynamics due to limited free knobs. To obtain a hybrid MBA lattice with better nonlinear dynamics performance, it is better to consider some indicators of nonlinear dynamics as objective functions in designing the linear optics using an optimization algorithm. In this paper, integral strengths of sextupoles and natural chromaticities are used as the nonlinear dynamics indicators, and different optimization methods with both or either of the two indicators are carried out and compared. As an example, a hybrid 7BA lattice with an energy of 2.4 GeV is designed towards an emittance of less than 70 pm·rad.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW055

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paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW056

Comparison of Constrained Optimization Methods for Designing a Multi-Bend Achromat Lattice

lattice, sextupole, storage-ring, linear-dynamics

1535

J.H. Xu, Z.H. Bai, W. Li, P.H. Yang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In the design of a multi-bend achromat (MBA) lattice for a diffraction-limited storage ring, there are usually many magnet parameters to be optimized and some stringent constraints to be satisfied. For example, to cancel out nonlinear dynamics effects, the phase advances between some sections are generally required to be set to certain values in the lattice design. For better designing a MBA lattice using an evolutionary algorithm, the handling of constraints will be important, because it is very hard to satisfy the constraints for most or even all of solutions in the early generations of the algorithm. This paper will first describe some methods for handling constraints, which are then applied to designing a hybrid 7BA lattice. The comparison of these methods shows that better lattice solutions can be obtained by including constraints into objective functions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW056

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paper received ※ 23 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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TUPGW057

A Ten-Bend Achromat Lattice with Interleaved Dispersion Bumps for a Diffraction-Limited Storage Ring

lattice, storage-ring, sextupole, quadrupole

1538

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Recently, a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps (IDB-MBA), was proposed to design the HALS storage ring, which presented better performance of both on- and off-momentum nonlinear dynamics. Since the beam emittance scales inversely with the third power of the number of bending magnets, in this paper we will study a new IDB-MBA lattice with more bending magnets. It is feasible to satisfy the requirement of the IDB-MBA concept in a 10BA lattice, and an IDB-10BA lattice is then designed for a storage ring light source with an energy of 2.4 GeV. The designed lattice has an ultra-low natural emittance of 81 pm·rad, and a dynamic aperture of about 6 mm and a large dynamic momentum aperture of 6% are achieved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW057

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paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW061

First Study for an Upgrade of the ALBA Lattice

lattice, injection, optics, dipole

1544

G. Benedetti, U. Iriso, Z. Martí, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

ALBA has started a study that will produce the design of a new lattice for a diffraction limited photon source. The baseline lattice should preserve the present circumference and energy, and keep the insertion device beamline source points as much as possible unchanged. The first solution is a 16-fold periodic ring based on a 7BA cell with dispersion bump, paired sextupoles and anti-bends. An emittance of 155 pm·rad would be reached without longitudinal gradient in the dipole magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW061

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPGW063

Studying the Dynamic Influence on the Stored Beam From a Coating in a Multipole Injection Kicker

injection, operation, kicker, simulation

1547

J. Kallestrup, Å. Andersson, J. Breunlin, D.K. Olsson, P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden
P. Alexandre, R. Ben El Fekih
SOLEIL, Gif-sur-Yvette, France

The MAX IV 3 GeV ring is the first synchrotron light source utilizing the Multi-Bend Achromat scheme to achieve a low horizontal bare-lattice emittance of 328 pm rad providing high brilliance x-rays for users. A novel Multipole Injection Kicker (MIK) designed and constructed by SOLEIL is used to allow top-up operation with only minor disturbances to the stored beam, i.e., the users. We investigate the stored beam perturbations due to quadrupole fields arising during the MIK pulse, originating from its inner coating. Maximum bunch emittance growth of §I{21}{πco\meter\radian} was found in simulations. Measurements of the stored beam impact are performed and found to be in good agreement with simulations. We conclude that the MIK at MAX IV 3 GeV has the potential to deliver quasi-transparent injections with good capture efficiency.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW063

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paper received ※ 06 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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TUPGW066

Exploring the Potential of the Swiss Light Source

storage-ring, operation, damping, cavity

1554

M. Aiba, M. Böge, A. Citterio, M.M. Dehler, A. Lüdeke, C. Ozkan Loch, L. Stingelin, A. Streun
PSI, Villigen PSI, Switzerland

Swiss Light Source (SLS) has been on-line since 2001. Although its performance meets the specifications, it still has a potential to achieve better storage ring beam parameters. We explore two possible improvements. The first one is for the beam lifetime. There are 480 rf buckets while normally 390 bunches are stored. The gap in filing pattern (90 empty buckets) is held to suppress ion instability. After many years of operation, however, the vacuum condition is much better than that of the time when the SLS was turned on. Hence it is possible to shorten the gap. The beam lifetime can then be prolonged due to less bunch current while keeping the net beam current. The study may be also useful to predict possible filling patter in SLS2, which is the SLS upgrade planned. The second one is for the beam emittance. The nominal energy closed orbit coincides with the axes of quadrupole magnets. An off-momentum closed orbit is therefore off-centered through quadrupoles, resulting in a damping partition shift. The beam emittance can be decreased at the expense of a larger energy spread. This was successfully achieved in the ESRF booster. We study whether it is applicable to the SLS storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW066

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPGW070

Multi-Bend Achromat Lattice Design for the Future of TPS Upgrade

lattice, dipole, storage-ring, dynamic-aperture

1564

M.-S. Chiu, P.J. Chou, J.C. Huang
NSRRC, Hsinchu, Taiwan
S.-Y. Lee
Indiana University, Bloomington, Indiana, USA

We present a TPS upgrade option with the hybrid 7BA (H7BA) lattice. We also derive a simple formula on optimal dipole angle distribution among H7BA dipoles. The agreement is satisfactory. We also report preliminary results on the dynamic aperture (DA) optimization. Possible improvement on H7BA lattice is outlined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW070

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paper received ※ 24 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW072

Design and Optimization of Full Energy Injector Linac for Siam Photon Source II

linac, storage-ring, injection, simulation

1570

T. Chanwattana, P. Klysubun, T. Pulampong, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand

The new Thailand synchrotron light source, Siam Photon Source II (SPS-II), has been designed based on a 3 GeV storage ring with a Double-Triple Bend Achromat (DTBA) lattice and a full energy injector linac. The linac consists of an S-band photocathode RF gun, C-band accelerating structures and two magnetic chicanes. In addition to its main function as the storage ring injector, the linac is capable of producing sub-picosecond electron bunches for additional short-pulse beamlines at the end of the linac. The linac also has a potential to become a driver of a soft X-ray Free Electron Laser (FEL) operating adjacent to the storage ring. In this paper, start-to-end simulations of the full energy linac are presented. Optimization was performed in order to fulfil requirements for both storage ring injection and short pulse generation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW072

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW075

Towards a Diffraction Limited Storage Ring

lattice, storage-ring, optics, dynamic-aperture

1573

J. Bengtsson
DLS, Oxfordshire, United Kingdom
P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden

A Lattice for a 500 m circ. Tunnel, based on First Principles & Best Practices is presented. Background: MAX-IV has made a "quantum leap" towards a Diffraction Limited Storage Ring (DLSR) by an Engineering-Science, i.e., Systems, Approach; leading to a Paradigm Shift(s): e.g. the Magnet Reference Radius is a Key Parameter, a Design Choice, that must be considered at an early stage for Robust Design. In addition, the pursuit of Systematic Benchmarks, MAX-I -> MAX-IV, has enabled the pursuit of Disruptive Technologies with Predictable Results. For example: Combined-Function Magnets (built-to-print) enabling an "IKEA Approach" (innovative, prompted by low-budget) like the use of Concrete Girders, Vacuum Requirements mitigated by NEG Coating, and Solid State Modulators providing a Reliable Injector by a Full-Energy Linac. Since "The Experiment" now has been done, Permanent Magnets, well understood for high-end Insertion Devices, provides another opportunity/step for a Next Generation. Besides, the Electricity Bill for Conventional Magnets is a significant part of the Operations Cost.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW075

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paper received ※ 20 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW079

Exploratory Lattice Design Studies for Diamond-II

lattice, controls, optics, dynamic-aperture

1589

B. Singh, R. Bartolini, J. Bengtsson, H. Ghasem, I.P.S. Martin
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

We pursue Robust Design of a Ring-Based Synchrotron Light Source as a System. In particular, the Design Phi-losophy is based on: ’ To Control the Nonlinear Dynamics: Control the Linear Optics. In particular, by: ’ Optimal Control of Natural Chromaticity. ’ ’-I Transformer’ between Chromatic Sextupoles for Unit Cell. ’ Higher-Order-Achromat for Super Period. In addition, by pushing the Requirements for Robust & Efficient Injection ’Upstream’, i.e., by considering On-Axis Injection, and by utilizing Reverse Bends (to trans-cend the reductionist Theoretical Minimum Emittance Cell), either: ’ the Natural Emittance can be reduced further, ’ or the Touschek Lifetime can be improved. Bottom line, a Design Choice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW079

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW080

Alternative Lattice Design for Diamond-II

lattice, sextupole, dipole, optics

1593

M. Korostelev
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Singh
DLS, Oxfordshire, United Kingdom

Plans for upgrade of the Diamond Light Source aim to reduce beam emittance by a factor of 20 or better. This is motivated by demand for photon flux with significantly high brightness and transverse coherence. The baseline lattice design for the Diamond-II upgrade has been recently proposed, however alternative design are under investigation to reduce the emittance even further. This paper presents a new lattice design based on implementation of bending magnets with transverse field gradient only.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW080

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW089

Tunable Bunch Train Generation Using Emittance Exchange Beamline With Transverse Wiggler

wiggler, controls, simulation, bunching

1612

G. Ha, M.E. Conde, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA

Funding: This work is supported by LDRD program at Argonne National Laboratory and Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
Emittance exchange beamline provides a unique correlation between the upstream transverse momentum and downstream longitudinal timing. Similar to the bunch train generation concept using energy modulation and chicane, the emittance exchange beamline can convert the transverse momentum modulation to the temporal modulation at the end of the beamline. The beam can obtain this transverse modulation from alternating magnet array (e.g. 90 degree rotated undulator). While most of other methods provide only one knob to control both micro-bunch length and bunch-to-bunch spacing or hard to control one of the knobs, this method provides separated knobs for the micro-bunch length and spacing and they are easy to control. These knobs enable to separately control the fundamental frequency of the radiation and its bandwidth. We plan to demonstrate this method at Argonne Wakefield Accelerator facility (AWA). This poster present progress on this new method and its demonstration at AWA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW089

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paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW091

Lattice Measurements of the APS Injector Rings

quadrupole, booster, lattice, dipole

1619

V. Sajaev, C. Yao
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357
APS Upgrade will feature an entirely new storage ring but will keep the existing injector complex consisting of the linear accelerator, Particle Accumulator Ring (PAR) and Booster. Due to small dynamic aperture of the APS Upgrade lattice, swap-out injection is adapted when an entire old bunch is replaced with a new bunch. This injection requires Booster to provide high-charge bunches with up to 17 nC in a single bunch. An extensive work is being carried out on characterizing the existing injector rings to ensure future high-charge operation. In this paper, we will present results of the lattice measurement using the response matrix fit. We will show the analysis of the achievable lattice measurement accuracy in the APS Booster and describe fit parameter modifications required to achieve good fit accuracy for the PAR.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW091

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW092

Working Impedance Model and Its Effect on the Intensity Limitation of Petra-IV Storage Ring

impedance, cavity, feedback, storage-ring

1623

Y.-C. Chae
DESY, Hamburg, Germany

We made sufficient progress in modeling the imped-ance of the PETRA-IV storage ring. The result was ap-plied to estimate the impedance-based single and multi-bunch intensity limit. Due to the extremely small emit-tance of the beam the intrabeam scattering (IBS) effects will be significant unless they are reduced by bunch lengthening. The 3rd harmonic cavity was proposed to dilute the bunch density which resulted in the small syn-chrotron frequency with a large spread. Because of the complexity introduced by impedance and harmonic cavity we used broadband impedance up to 200 GHz to compute the parameters such as bunch length and energy spread at different currents. We found that the microwave instability started very early in current less than 0.5 mA. Even if it is small, the prediction by tracking simulation was consistent with another diffraction-limited storage ring (DLSR) when the Keil-Schnell criterion was used to predict one from the other. Then, we present the single-bunch current limit which had included the effect of geometric and resistive wall impedances of the NEG-coated chamber. Finally, we present the emittance and lifetime which can be realistically achieved in the ring with the above collective effects included.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW092

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW093

Compensation of Insertion Device Induced Emittance Variations in Ultralow Emittance Storage Rings by a Dispersion Bump in a Wiggler

wiggler, storage-ring, lattice, dipole

1627

F. Sannibale, M.P. Ehrlichman, T. Hellert, S.C. Leemann, D. Robin, C. Steier, C. Sun, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
Multi-bend achromat lattices allow for the design of extremely low emittance electron storage rings and hence for the realization of extremely high- brightness X-ray photon sources. In these new rings, the beam energy lost to radiation in the insertion devices (IDs) is often comparable to that lost in the ring dipole magnets. This implies that with respect to the typical 3rd generation light source, these new machines are more sensitive to the energy loss variations randomly occurring as the many users independently operate the gap of their IDs. The consequent induced variations in radiation damping time, equilibrium emittance, and transverse beam sizes at the radiation point sources can be significant and degrade the experimental performance in some of the beam-lines. In this paper we describe and discuss a possible method to compensate for such emittance variations by using a variable dispersion bump localized inside a fixed gap wiggler.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW093

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW094

First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization

experiment, quadrupole, storage-ring, operation

1631

S.C. Leemann, Ph. Amstutz, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini
LBNL, Berkeley, USA

Funding: This research is funded by US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW094

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW095

Progress on a Novel 7BA Lattice for a 196-m Circumference Diffraction-Limited Soft X-Ray Storage Ring

lattice, sextupole, optics, storage-ring

1635

S.C. Leemann, F. Sannibale
LBNL, Berkeley, USA
M. Aiba, A. Streun
PSI, Villigen PSI, Switzerland
J. Bengtsson
DLS, Oxfordshire, United Kingdom
L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS Upgrade to a diffraction-limited soft x-ray storage ring calls for ultralow emittance in a very limited circumference. In this paper we report on progress with a lattice based on a 7BA with distributed chromatic correction. This lattice relies heavily on longitudinal gradient bends and reverse bending in order to suppress the emittance, so that, despite having only seven bends, ultralow emittance can be achieved in addition to large dynamic aperture and momentum acceptance. An initial alternate 7BA lattice has been revised to relax magnet requirements as well as further increase off-energy performance and resilience to machine imperfections. We now demonstrate ±2.5 mm dynamic aperture including errors and calculate the effect of IBS to show that this lattice achieves 6 hours Touschek lifetime (at 500 mA, including errors) and a brightness of roughly 3x10²¹ ph/s/mm²/mrad²/0.1%BW at 1 keV.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW095

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW097

Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source

lattice, cavity, storage-ring, vacuum

1639

C. Steier, Ph. Amstutz, K.M. Baptiste, P.A. Bong, E.S. Buice, P.W. Casey, K. Chow, S. De Santis, R.J. Donahue, M.P. Ehrlichman, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, R.M. Leftwich-Vann, D. Leitner, T.H. Luo, O. Omolayo, J.R. Osborn, G. Penn, G.J. Portmann, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097

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paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW109

Conceptual Design of Vacuum Chamber for SPS-II Storage Ring

vacuum, storage-ring, photon, impedance

1666

T. Phimsen, S. Chaichuay, N. Juntong, P. Klysubun, S. Prawanta, P. Sudmuang, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand
R. Deepan, A. Khamkham
Suranaree University of Technology, Nakhon Ratchasima, Thailand

The SPS-II is a 3 GeV ultralow emittance light source which is now under studied and designed by Thailand Synchrotron Light Research Institute (SLRI). The SPS-II storage ring is based on Double-Triple Bend Achromat (DTBA) cell with a circumference of 321.3 m aiming for horizontal emittance of less than 1 nm-rad. The compact lattice leaves narrow space for vacuum components. The small gap between poles of the magnets requires narrow vacuum chambers and limits the conductance of the chambers. The chambers will be made by stainless steel with a thickness of 1.5 mm. the cross section of beam duct is 40 mm × 16 mm elliptical shape. The bending chamber is designed as a long triangular chamber such that photon absorber can be installed as far from the light source as possible to lower the power density of the heat load. The overview of designed vacuum system for the SPS-II is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW109

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB026

Optics & Compression Schemes for a Possible FLASH Upgrade

FEL, electron, laser, simulation

1744

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

The proposed FLASH upgrade will rely on high quality electron beams provided to all undulator beamlines. Here we describe possible modifications to the FLASH lattice and the compression scheme that aim at improving the beam quality and the ability to control critical beam properties along the machine - simultaneously and independently for all beamlines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB026

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paper received ※ 11 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB053

Injector Physics Design at SHINE

laser, electron, feedback, FEL

1801

Z. Wang, M.H. Zhao
SINAP, Shanghai, People’s Republic of China
Q. Gu
SSRF, Shanghai, People’s Republic of China
G.L. Wang
DICP, Dalian, People’s Republic of China

As a CW x-ray free electron laser facility, SHINE has a high requirement on the electron beam quality in the linac, as well as in the injector. SHINE injector consists of a 162.5 MHz normal conducting VHF gun, a NC 1.3 GHz RF buncher, a one cavity SC cryomodule, an eight cavity SC cryomodule and 3 solenoids along the injector layout. Some beam diagnostic element are inserted in the layout as well. In this paper, we try to introduce the injector physics design at shine.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB053

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPRB105

Realizing Low-Emittance Lattice Solutions With Complex Bends

lattice, dipole, quadrupole, sextupole

1906

V.V. Smaluk, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: Department of Energy Contract No. DE-SC0012704
A concept of new lattice element called "Complex Bend" is recently proposed at NSLS-II. Replacing the regular dipoles in the Double-Bend Achromat lattice by Complex Bends significantly reduces the beam emittance. The first attempt of lattice design for potential NSLS-II upgrade based on Complex Bend, is described. Compared with the current NSLS-II lattice, the new solution modifies only three of the six girders per cell. The linear optics has been matched keeping unchanged the lattice parameters at the straight sections, where the light-generating insertion devices are located. The Complex Bend gradient is limited by 250 T/m assuming possible use of permanent magnets. The lattice provides 65 pm emittance without damping wigglers, use of which results in further decrease of the emittance

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB105

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB112

JLEIC: A High Luminosity Polarized Electron-Ion Collider at Jefferson Lab

electron, collider, luminosity, proton

1916

Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The recent National Academies of Science Review concluded the science questions that could be answered by an electron-ion collider are significant to advancing our understanding of the atomic nuclei that make up all visible matter in the universe. To meet this science need, a high luminosity polarized electron-ion collider (JLEIC) was envisioned at Jefferson Lab, based on the existing CEBAF recirculated SRF electron linac. Over the past 16 years, Jefferson Lab has been actively engaged in the design study and accelerator R&D for JLEIC, a comprehensive Pre-Conceptual Design Report has been completed recently. The JLEIC baseline design has also been continuously optimized including extending the CM energy to 100 GeV. In this paper, we present a summary of the JLEIC baseline design and also briefly discuss the accelerator R&D.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB112

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paper received ※ 07 June 2019 paper accepted ※ 07 June 2019 issue date ※ 21 June 2019

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TUPRB117

Disk and Washer Coupled Cavity Linac Design and Cold-Model for Muon Linac

cavity, linac, acceleration, operation

1924

M. Otani, N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Futatsukawa, T. Mibe, F. Naito
KEK, Ibaraki, Japan
K. Hasegawa, T. Ito, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan

Funding: This work was supported by JSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707.
A disk and washer (DAW) coupled cavity linac (CCL) has been developed for a middle velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.3 to 0.7 at an operational frequency of 1296 MHz. In this poster, the cavity designs, beam dynamics designs, and the cold-model measurements will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB117

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paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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TUPTS007

SPIRAL2 RFQ Bunch Length and Longitudinal Emittance Measurements.

simulation, rfq, proton, linac

1944

G. Normand, M. Di Giacomo, R. Ferdinand, O. Kamalou, J.-M. Lagniel, A. Savalle
GANIL, Caen, France
D. Uriot
CEA-DRF-IRFU, France

The SPIRAL2 RFQ is designed to accelerate light and heavy ions up to A/Q=3 in CW mode to 0.75MeV/u. During its commissioning, the bunch lengths measured using a Beam Extension Monitor were compared with simulations for different ion species (Proton, Helium, Oxygen, Argon). The longitudinal emittances measured using the 3 gradients method and a multiparticule optimization method were also compared successfully to the expected ones.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS007

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paper received ※ 19 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS012

Emittance Reduction of RF Photoinjector Generated Electron Beams By Transverse Laser Beam Shaping

laser, simulation, cathode, experiment

1958

M. Groß, P. Boonpornprasert, Y. Chen, J.D. Good, H. Huck, I.I. Isaev, C. Koschitzki, M. Krasilnikov, S. Lal, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, S.K. Mohanty, R. Niemczyk, A. Oppelt, H.J. Qian, H. Shaker, G. Shu, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
I. Will
MBI, Berlin, Germany

Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF photoinjectors. Ultimately high performance can be achieved with ellipsoidal laser pulses, but 3-dimensional shaping is challenging. High beam quality can also be reached by simple transverse pulse shaping, which has demonstrated improved beam emittance compared to a transversely uniform laser in the ‘pancake’ photoemission regime. In this contribution we present the truncation of a Gaussian laser at a radius of approximately one σ in the intermediate (electron bunch length directly after emission about the same as radius) photoemission regime with high acceleration gradients (up to 60 MV/m). This type of electron bunch is used e.g. at the European XFEL and FLASH free electron lasers at DESY, Hamburg site and is being investigated in detail at the Photoinjector Test facility at DESY in Zeuthen (PITZ). Here we present ray-tracing simulations and experimental data of a laser beamline upgrade enabling variable transverse truncation. Initial projected emittance measurements taken with help of this setup are shown, as well as supporting beam dynamics simulations. Additional simulations show the potential for substantial reduction of slice emittance at PITZ.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS012

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paper received ※ 24 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPTS014

SINGLE SHOT CATHODE TRANSVERSE MOMENTUM IMAGING IN PHOTOINJECTORS

cathode, solenoid, electron, simulation

1964

P.W. Huang, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, S. Lal, X. Li, O. Lishilin, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, H. Shaker, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA
C.-X. Tang
TUB, Beijing, People’s Republic of China
W. Wan
ShanghaiTech University, Shanghai, People’s Republic of China

In state of the art photoinjector electron sources, cathode performance determines the lower limit of achievable beam emittance. Measuring the thermal emittance at the photocathodes in electron guns is of vital importance for improving the injectors. Traditional methods, like solenoid scan, pepper-pot, need multi-shots and are time-consuming, therefore suffer from machine stability. Here we propose a new method, named cathode transverse momentum imaging. By tuning the gun solenoid focusing, the electrons’ transverse momentum at the cathode is imaged to a downstream screen, which enables a single shot measurement. Several experiments have been done at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) with a Cs2Te cathode. Measurements of cathode transverse momentum, the corresponding spectra, cathode transverse momentum map and its correlation with surface electric field are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS014

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS024

Design of a Full C-Band Injector for Ultra-High Brightness Electron Beam

gun, cathode, klystron, brightness

1979

D. Alesini, F. Cardelli, G. Castorina, M. Croia, M. Diomede, M. Ferrario, A. Gallo, A. Giribono, B. Spataro, C. Vaccarezza, A. Vannozzi
INFN/LNF, Frascati (Roma), Italy

High gradient rf photo-injectors have been a key development to enable several applications of high quality electron beams. They allow the generation of beams with very high peak current and low transverse emittance, satisfying the tight demands for free-electron lasers, energy recovery linacs, Compton/Thomson sources and high-energy linear colliders. In the paper we present the design of a new full C-band RF photo-injector recently developed in the framework of the XLS-Compact Light design study and of the EuPRAXIA@SPARC_LAB proposal. It allows to reach extremely good beam performances in terms of beam emittance (at the level of few hundreds nm), energy spread and peak current. The photo-injector is based on a very high gradient (>200 MV/m) ultra-fast (RF pulses <200 ns) C-band RF gun, followed by two C band TW structures. Different types of couplers for the 1.6 cell RF gun have been considered and also a new compact low pulsed heating coupler working on the TM020 mode on the full cell has been proposed. In the paper we report the design criteria of the gun, the powering system, and the results of the beam dynamics simulations. We also discuss the case of 1 kHz repetition rate.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS024

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS038

The Operation Status of CSNS Front End

rfq, ion-source, LEBT, operation

2024

Y.W. An, Y.J. Lv, H.F. Ouyang, Y.C. Xiao
IHEP, Beijing, People’s Republic of China
X. Cao, W. Chen, T. Huang, H. Li, S. Liu, K. Xue
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: Work supported by National Natural Science Foundation of China(11875271)
China spallation neutron source (CSNS), as the China’s first 100kW beam power pulsed neutron source, its operation target beam power is now larger than 50kW. During the beam power upgrading process of CSNS to 50kW from 2018 to 2019, many improvements have been made for the front end of CSNS. In this paper, the commissioning and improvement of front end as well as the laboratory construction are introduced. The improvements mainly focus on solving the stability of ion source and the spark of Radio Frequncy quadrupole (RFQ) caused by the pre-chopped beam into RFQ.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS038

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paper received ※ 08 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS047

Improvement of 6D Brightness by a 1.4-cell Photocathode RF Gun for MeV Ultrafast Electron Diffraction

gun, electron, cathode, brightness

2033

Y. Song
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
K. Fan, C.-Y. Tsai, Y.T. Yang
HUST, Wuhan, People’s Republic of China
J. Yang
ISIR, Osaka, Japan

Recent research indicates that ultrafast electron diffraction and microscopy (UED/M) have unprecedented potential in probing ultrafast dynamic processes, especially in organic and biological materials. However, reaching the required brightness while maintaining high spatiotemporal resolution requires new design of electron source. In order to produce ultrashort electron beam with extreme high brightness, a 1.4-cell RF gun is being developed to reach higher acceleration gradient near the photocathode and thus suppress the space charge effect in the low energy region. Simulation of the 1.4-cell RF photocathode gun shows considerable improvement in bunch length, emittance and energy spread, which all lead to better temporal and spatial resolution comparing to traditional 1.6-cell RF photocathode gun. The results demonstrate the feasibility of sub-ps temporal resolution with normalized emittance less than 0.1 πmm·mrad while maintaining 1 pC electron pulse.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS047

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paper received ※ 24 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS054

1st+2nd Harmonic Photocathode Bimodal Gun R&D

gun, cathode, electron, cavity

2054

L. Wang
SINAP, Shanghai, People’s Republic of China
W. Fang, Z.T. Zhao
SSRF, Shanghai, People’s Republic of China
J.L. Hirshfield
Yale University, Physics Department, New Haven, CT, USA
J.L. Hirshfield, S.V. Shchelkunov
Omega-P, Inc., New Haven, Connecticut, USA
Y. Jiang, S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
L. Wang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

Funding: U.S. Dept. of Energy
A novel Bimodal Electron Gun is designed to apply microwaves at two harmonically-related frequency in a 0.6 cell RF gun to increase the RF breakdown threshold and enhance the beam quality. This stratagem is intended to allow the RF gun structure to support a high accelera-tion gradient as well as to manipulate the emittance evolution in the half cell. By selecting a proper ampli-tude ratio and phase relationship between the first and second harmonic RF field components in the gun cavity, the superposition of the harmonic field components can provide a flat-top like RF profile to omitting the RF emittance component in the gun, while increase the RF breakdown threshold. The recent status of the Bimodal Electron Gun R&D is presented, including the designs of the novel two frequency RF structure and the simulation of the beam dynamic.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS054

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS061

The Pre-Injector and Photocathode Gun Design for the MAX IV SXL

gun, cathode, linac, laser

2064

J. Andersson, F. Curbis, L. Isaksson, M. Kotur, D. Kumbaro, F. Lindau, E. Mansten, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

The design of the pre-injector, including the new gun, for the SXL project is being finalised for the desired modes of operation, 100 pC and 10 pC with short bunches. The photocathode gun is currently being manufactured and experiments in the MAX IV guntest facility are under preparation to verify the design. In this paper we present the design of the gun and the pre-injector and show some results from simulations using MOGA indicating an emittance below 0.3 mm mrad.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS061

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS080

Beam Dynamics Studies of an APEX2-Based Photoinjector

solenoid, gun, cathode, focusing

2109

C.E. Mitchell, H.Q. Feng, D. Filippetto, M.J. Johnson, A.R. Lambert, D. Li, T.H. Luo, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells
LBNL, Berkeley, California, USA

APEX2 is a proposed normal conducting radio-frequency (RF) electron gun operating in the very high frequency (VHF) range in continuous wave (CW) mode, designed to drive applications that require both high beam brightness and high repetition rate, such as free electron lasers (such as LCLS-II-HE), ultra-fast electron diffraction, and microscopy. The gun consists of a two-cell RF cavity operating at 162.5 MHz with a cathode field of 34 MV/m, together with an embedded focusing solenoid. We study the beam dynamics in an APEX-II-based photoinjector (up to ~20 MeV), targeting a transverse 95% beam emittance of 0.1 um at 12.5 A peak current for the case of 100 pC charge for FEL applications. The high cathode field leads to enhanced beam brightness, while the increased gun exit energy of ~1.5 MeV reduces the effects of space charge, and possibly eliminates the need for an RF buncher. The embedded solenoid is designed to control the transverse beam size while minimizing emittance growth due to geometric aberrations. As a result, the transverse beam performance targets are achieved, and ongoing work will further optimize longitudinal beam quality for downstream FEL transport.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS080

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS085

Design Study of 3.6-cell C-band Photocathode Electron Gun

gun, simulation, FEL, cathode

2121

W. Fang, Z.T. Zhao
SSRF, Shanghai, People’s Republic of China
L. Wang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China
L. Wang
SINAP, Shanghai, People’s Republic of China

A C-band photocathode injector composed of a 3.6-cell C-band photocathode RF gun and two 1.8-meter C-band accelerating structures is proposed. The injector is a low emittance electron source for Free Electron Lasers (FEL) and other compact light sources. The RF structure of the cavities is designed with 2D SUPERFISH simulation. The Beam dynamic study in ASTRA helps rectify the 2D RF simulation. To feed the cavities, a design of extra coaxial coupler with RF gun structure is presented. With compact focusing solenoids, for 0.25nC bunch charge, the final energy can reach 6.9 MeV energy and the 95% emittance can be as low as 0.23 mm mrad (95%). All the details of RF design and beam dynamics studies are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS085

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paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPTS088

A Normal Conducting RF Gun as an Electron Source for JLEIC Cooling

gun, electron, cathode, solenoid

2127

F.E. Hannon, R.A. Rimmer
JLab, Newport News, Virginia, USA

The baseline design for a magnetized injector for the bunched-beam electron cooler ring, as part of the Jeffer-son Lab Electron Ion Collider (JLEIC) uses a DC photo-cathode electron gun as the source. A challenging aspect of this concept is transporting a 3.2nC electron bunch at low energy and preserving the angular momentum. An RF gun source has been investigated to gauge the potential advantages of high gradient on the photocathode and higher exit energy. The design is presented and compared with the baseline results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS088

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS093

Magnetized Gridded Thermionic Electron Source

electron, gun, cathode, simulation

2140

M.S. Stefani
ODU, Norfolk, Virginia, USA
C.M. Gulliford, V.O. Kostroun, C.E. Mayes, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
F.E. Hannon, M. Poelker, R. Suleiman
JLab, Newport News, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. The demand for high average current for effective ion beam cooling has caused consideration of using bunched magnetized electron beam produced by a gridded thermionic electron gun. This paper presents the design of a potential electron source for JCIEC first measurements characterizing the beam properties of a magnetized thermionic gun.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS093

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS104

Spatio-Temporal Shaping of the Photocathode Laser Pulse for Low-Emittance Shaped Electron Bunches

laser, electron, cathode, simulation

2163

T. Xu, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
P. Piot
Fermilab, Batavia, Illinois, USA
J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by the U.S. DOE contract No. DE- SC0017750 with Euclid Techlabs LLC., No. DE-SC0018656 with NIU, and No. DE-AC02-06CH11357 with ANL.
Photocathode laser shaping techniques to generate temporally shaped electron bunches are appealing owing to their simplicity. Such technique is being considered to form shaped electron bunches to enhance the transformer ratio in beam-driven accelerators. At low energy (i.e. during the emission process) the transverse and longitudinal space charge effects are coupled so that attaining a low beam transverse emittance require the laser to be spatiotemporal shaped. In this paper, we explore the generation of a linearly-ramped bunch with optimized transverse emittance by temporally and radially shaping the laser pulse to provide an adequate initial distribution. We discuss a possible implementation of the optical shaping technique and describe a planned experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS104

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS105

High Current High Charge Magnetized and Bunched Electron Beam from a DC Photogun for JLEIC Cooler

cathode, laser, electron, gun

2167

S. Zhang, P.A. Adderley, J.F. Benesch, D.B. Bullard, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman, M.G. Tiefenback, Y.W. Wang
JLab, Newport News, Virginia, USA
J.R. Delayen, G.A. Krafft, Y.W. Wang, S.A.K. Wijethunga
ODU, Norfolk, Virginia, USA

Funding: This project was supported by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177. Additional support comes from Laboratory Directed Research and Development program.
A high current, high charge magnetized electron beamline that has been under development for fast and efficient cooling of ion beams for the proposed Jefferson Lab Electron Ion Collider (JLEIC). In this paper, we present the latest progress over the past year that include the generation of picosecond magnetized beam bunches at average currents up to 28 mA with exceptionally long photocathode lifetime, and the demonstrations of magnetized beam with high bunch charge up to 700 pC at 10s of kHz repetition rates. Detailed studies on a stable drive laser system, long lifetime photocathode, beam magnetization effect, beam diagnostics, and a comparison between experiment and simulations will also be reported. These accomplishes marked an important step towards the essential feasibility for the JLEIC cooler design using magnetized beams.
(To be inserted)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS105

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEZZPLS2

EuPRAXIA, a Step Toward a Plasma-Wakefield Based Accelerator With High Beam Quality

plasma, laser, injection, acceleration

2291

P.A.P. Nghiem, A. Chancé
CEA-IRFU, Gif-sur-Yvette, France
D. Alesini, E. Chiadroni, M. Croia, A. Del Dotto, M. Ferrario, A. Giribono, R. Pompili, S. Romeo, V. Shpakov, A. Stella, C. Vaccarezza
INFN/LNF, Frascati, Italy
A. Aschikhin, R.W. Aßmann, U. Dorda, A. Ferran Pousa, V. Libov, B. Marchetti, A. Martinez de la Ossa, D. Marx, P. Niknejadi, L. Schaper, E.N. Svystun, P.A. Walker, M.K. Weikum, J. Zhu
DESY, Hamburg, Germany
T. Audet, B. Cros, P. Lee, G. Maynard
CNRS LPGP Univ Paris Sud, Orsay, France
A. Beck, F. Massimo, A. Specka
LLR, Palaiseau, France
M. Chen, S.M. Weng
Shanghai Jiao Tong University, Shanghai, People’s Republic of China
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.-E. Couprie, A. Ghaith, D. Oumbarek Espinos
SOLEIL, Gif-sur-Yvette, France
G. Dattoli, F. Nguyen
ENEA C.R. Frascati, Frascati (Roma), Italy
N. Delerue
LAL, Orsay, France
R.A. Fonseca, L.O. Silva
Instituto Superior Tecnico, Lisbon, Portugal
L.A. Gizzi, G. Toci, P. Tomassini
INO-CNR, Pisa, Italy
A. Helm
IST-UTL, Lisbon, Portugal
B. Hidding
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S.M. Hooker, R. Walczak
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
M.G. Ibison, M. Vujanovic, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
D.A. Jaroszynski, F.Y. Li, Z.M. Sheng, S.M. Wiggins, S. Yoffe
USTRAT/SUPA, Glasgow, United Kingdom
K.O. Kruchinin, A.Y. Molodozhentsev
ELI-BEAMS, Prague, Czech Republic
L. Labate
CNR/IPP, Pisa, Italy
X. Li
DESY Zeuthen, Zeuthen, Germany
F. Mathieu
LULI, Palaiseau, France
Z. Mazzotta
Ecole Polytechnique, Palaiseau, France
T.J. Mehrling
LBNL, Berkeley, USA
A. Mosnier, C. Simon
CEA, Gif-sur-Yvette, France
A. Mostacci
Rome University La Sapienza, Roma, Italy
Z. Najmudin
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
R. Pattathil, D. Symes
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
A.R. Rossi
INFN-Milano, Milano, Italy
T. Silva, J.M. Vieira
IPFN, Lisbon, Portugal
M.J.V. Streeter
JAI, London, United Kingdom
D. Terzani
UniNa, Napoli, Italy

Funding: European Union’s Horizon 2020 research and innovation programme under grant agreement No. 653782
The EuPRAXIA project aims at designing the world’s first accelerator based on plasma-wakefield advanced technique, which can deliver a 5 GeV electron beam with simultaneously high charge, low emittance and low energy spread to user’s communities. Such challenging objectives can only have a chance to be achieved when particular efforts are dedicated to identify the subsequent issues and to find the way to solve them. Many injection/acceleration schemes and techniques have been explored by means of thorough simulations in more than ten European institutes to sort out the most appropriate ones. The specific issues of high charge, high beam quality and beam extraction then transfer to the user’s applications, have been tackled with many innovative approaches*. This article highlights the different advanced methods that have been employed by the EuPRAXIA collaboration and the preliminary results obtained. The needs in terms of laser and plasma parameters for such an accelerator are also summarized.
*- in 2017: Phys. Plasmas, 24,10,103120; Nat. Commun.8,15705; - in 2018: NIMA, 909,84-89; NIMA, 909,49-53; Phys. Rev.Acc. Beams, 21,111301; NIMA, 909,54-57; Phys. Rev.Acc. Beams, 21,052802; NIMA, 909,282-285

Slides WEZZPLS2 [5.157 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZZPLS2

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paper received ※ 12 April 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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WEPMP021

Frequency Modulated Capture of Cooled Coasting Ion Beams

low-level-rf, injection, operation, simulation

2356

S.C.P. Albright, M.E. Angoletta
CERN, Geneva, Switzerland

Transverse space charge effects in the Low Energy Ion Ring (LEIR) at CERN have been shown to be a major source of particle losses, which can be mitigated with a larger RMS longitudinal emittance. However, due to electron cooling during the injection plateau, the longitudinal density is very high prior to RF capture. In addition there is an uncontrolled cycle to cycle variation in the revolution frequency of the coasting beam on the flat bottom, which degrades the beam quality at capture. In this paper we show that applying an RF frequency modulation during the capture process allows both a controlled blow-up of the longitudinal emittance and a very good reproducibility in the longitudinal distribution, which in turn improves beam transmission through the machine.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP021

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paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP025

Matching Studies Between CERN PSB and PS Through Multi-Turn Beam Profile Acquisitions

injection, optics, betatron, operation

2367

M.A. Fraser, Y. Dutheil, V. Forte, A. Guerrero, A. Huschauer, A. Oeftiger, S. Ogur, F. Roncarolo, E. Senes, F. Tecker
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade (LIU) project, the investigation and quantification of the optics mismatch between the CERN Proton Synchrotron Booster (PSB) and PS is a crucial step in understanding the source of horizontal emittance growth between the two machines. Extensive studies were carried out to estimate the mismatch from single-pass measurements in the transfer line and to rematch the transfer line to reduce the dispersive mismatch at PS injection while keeping the betatron matching unaltered. This paper presents the results of the data analysis of more recent multi-turn measurements, which profited from a new turn-by-turn beam profile monitor in the PS ring, to assess the achieved level of matching and corresponding emittance growth. The results confirm the improved matching and demonstrate the feasibility of the multi-turn technique as a fundamental tool that will be important for the recommissioning of the renovated transfer line after Long Shutdown 2.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP025

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP026

Emittance Dilution from the CERN Proton Synchrotron Booster’s Extraction Kickers

kicker, extraction, operation, proton

2371

M.A. Fraser, S.C.P. Albright, F. Antoniou, G.P. Di Giovanni, Y. Dutheil, V. Forte, A. Huschauer, F. Roncarolo
CERN, Meyrin, Switzerland

Understanding the different sources of emittance dilution along the LHC injector chain is an important part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantify the transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS). In this contribution, the waveform measurement technique will be briefly outlined before the results and their implications for the LIU project and beam performance reach are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP026

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP030

LHC Injection Losses and Trajectories During Run 1 and 2 and Outlook to Injection of HL-LHC Beams

injection, extraction, kicker, operation

2387

W. Bartmann, C. Bracco, B. Goddard, F.M. Velotti, J. Wenninger
CERN, Geneva, Switzerland

The LHC turn-around time is impacted by the control of injection losses and trajectories. While shot-to-shot trajectory variations dominated the injection efficiency during LHC Run 1, several improvements of hardware and operational settings allowed for a high rate of successful injections during Run 2. Injection losses and trajectories are analysed and presented for the high intensity proton runs, as well as for different beam types used from the injectors. Based on this analysis, an outlook is shown for the HL-LHC era, where double the bunch intensity will have to be injected.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP030

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPMP039

The New Injection Region of the CERN PS Booster

injection, linac, proton, booster

2414

W.J.M. Weterings, C. Bracco, L.O. Jorat, M. Meddahi, R. Noulibos, P. Van Trappen
CERN, Geneva, Switzerland

During the Long Shutdown 2 (LS2) at CERN, the new Linac4 (L4) accelerator will be connected to the PS Booster (PSB) to inject 160 MeV H⁻ beam into the 4 superposed PSB rings. In order to achieve this, we have designed, built and pre-assembled a completely new H⁻ charge-exchange injection chicane system, with a carbon stripping foil unit to convert the negative hydrogen ions into protons by stripping off the electrons. In parallel, we have built and installed a test stand in the L4 transfer line enabling us to gain valuable experience with operation of the stripping foil system and to evaluate different foil types during the L4 reliability runs. This paper describes the final design of the new PSB injection region and reports on the important test results obtained with the stripping foil test stand.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP039

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW025

High Level Software for Beam 6D Phase Space Characterization

simulation, diagnostics, gun, quadrupole

2522

V. Martinelli, D. Alesini, M. Ferrario, A. Giribono, S. Pioli, C. Vaccarezza, A. Variola
INFN/LNF, Frascati, Italy
A. Bacci
INFN-Milano, Milano, Italy

Operation of modern particle accelerators require high qualitity beams and conseguently sensitive diagnostic system in order to monitories and characterize the beam during the acceleration and transport. A turn-key high level software BOLINA (Beam Orbit for Linear Accelerators) has been developed to fully characterise the 6D beam phase space in order to help operator during commissioning with an easily scalable suite for any high brightness LINAC. In this work will be presented the diagnostic toolkit is presented as designed for the ELI-NP Gamma Beam System (GBS) a radiation source based on the Compton back scattering effect able to provide tunable gamma rays in the 0.2-20 MeV range with narrow bandwidth (0.3% and a high spectral density (10⁴ photons/sec/eV) by the Compton backscattering effect. BOLINA suite is design to be machine independent, thanks to the file exchanges with the EPICS based control system. Simulation of raw data of the ELI-NP-GBS accelerator has been used to test the capabilities of the diagnostic toolkit.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW025

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW039

Multi-Ribbon Profile Monitor for High Power Proton Beam at J-PARC MR Abort Line

target, proton, extraction, electron

2561

K. Sato
The University of Tokyo, Graduate School of Science, Tokyo, Japan
E. Hamada, Y. Hashimoto, S. Igarashi, T. Koseki, Y. Sato
KEK, Tsukuba, Japan

Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.6×10¹⁴ in the FX mode. Now we are planning to increase the ppp further up to 3.3×10¹⁴ in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires / ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system.

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paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW062

Synchrotron Light Diagnostic Beamline Design for HEPS Storage Ring

photon, diagnostics, storage-ring, lattice

2619

D.C. Zhu, J.S. Cao, Y.F. Sui, J.H. Yue
IHEP, Beijing, People’s Republic of China

Funding: National Nature Science Foundation of China(11605213)
High Energy Photon Source (HEPS) is a 6 GeV ul-tralow-emittance storage ring light source to be built in Beijing, China. With a multiple-bend achromat lattice design, the storage ring is expected to achieve an ul-tralow emittance of 34 pm.rad. The horizontal and verti-cal beam sizes will be in the sub-10 μm level. Beam emit-tance will be measured with x-ray diagnostic beamline at a low dispersion bending magnet source point. A visible light beamline will be designed to measure the bunch length and purity. In this paper, we will introduce the x-ray beamline, which combine with different techniques to resolve beam sizes and emittance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW062

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW076

Initial Performance of the Beam Instrumentation for the ESS IS & LEBT

LEBT, MMI, ion-source, diagnostics

2650

C.S. Derrez, R.A. Baron, R.E. Bebb, E.C. Bergman, I. Dolenc Kittelmann, E.M. Donegani, T. Fay, T.J. Grandsaert, V. Grishin, S. Haghtalab, H. Hassanzadegan, A. Jansson, H. Kocevar, E. Laface, Ø. Midttun, R. Miyamoto, J. Norin, K.E. Rosengren, T.J. Shea, A.G. Sosa, R. Tarkeshian, L. Tchelidze, C.A. Thomas, P.L. van Velze
ESS, Lund, Sweden

The European Spallation Source (ESS) is currently under construction in Lund (Sweden), and its 5 MW of average beam power at repetition rate of 14 Hz will make it five times more powerful than other pulsed neutron-scattering facilities. High-energy neutrons will be produced via spallation by 2 GeV protons on a tungsten target. A complete suite of beam diagnostics will enable tuning, monitoring and protection of the proton accelerator during commissioning, studies and operation. As an initial step toward neutron production, the Ion Source (ISrc) and the 75keV Low Energy Beam Transport Line (LEBT) have been installed. For the commissioning and characterization of this first beam-producing system, a subset of the ISrc and LEBT diagnostics suite has been deployed. This includes the following equipment: a Faraday cup, beam current transformers, an Allison Scanner emittance measurement unit, beam-induced fluorescence monitors, and a Doppler-shift spectroscopy system. Beam instrumentation deployment and performance verification, as well as the operational experience during the initial beam commissioning, will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW076

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paper received ※ 17 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW080

Design of Resonant Stripline BPM for an IR-FEL Project at NSRL

FEL, dipole, electron, vacuum

2665

X.Y. Liu, B.G. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China
M. Bopp, M.M. Dehler, X.Y. Liu, A. Scherer
PSI, Villigen PSI, Switzerland

Funding: Work supported by the National Science Foundation of China (11575181, 21327901, 11705203); X. Y. Liu was supported by the China Scholarship Council for a 2-year study at PSI (Grant No. 201706340057).
This paper presents the design of a 476MHz resonant stripline beam position monitor (BPM) for an IR-FEL machine at NSRL. This type of BPM was developed based on stripline BPM by moving the coupling feedthrough closer to the short end downstream. This modification introduces a resonance that gives this BPM a better capability to detect lower beam currents compared to broadband devices like button and stripline BPM. Meanwhile, the change is small enough to use the same type of electronics [1-3]. In the following sections, the basic principle, nonlinear effect, sensitivity, the filtered sum and difference signals, and the mechanical design of this BPM will be mainly discussed.
Email address: xiaoyu.liu@psi.ch

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW080

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW084

Measuring Beamsize with the LHC Beam Gas Vertex Detector

detector, proton, injection, luminosity

2680

B. Würkner, A. Alexopoulos, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, V. Kain, R. Kieffer, R. Matev, M.N. Rihl, V. Salustino Guimaraes, R. Veness, S. Vlachos
CERN, Geneva, Switzerland
A. Bay, F. Blanc, S. Gianì, O. Girard, G.J. Haefeli, P. Hopchev, A. Kuonen, T. Nakada, O. Schneider, M. Tobin, Z. Xu
EPFL, Lausanne, Switzerland
R. Greim, T. Kirn, S. Schael, M. Wlochal
RWTH, Aachen, Germany

The Beam Gas Vertex detector (BGV) is an innovative beam profile monitor being developed as part of the High Luminosity LHC (HL-LHC) project at CERN. The goal is to continually measure the transverse beam size by reconstructing beam-gas interaction vertices using high precision tracking detectors. To confirm the feasibility of such a device, a demonstrator based on eight modules of scintillating fiber detectors has been constructed, installed in the LHC and operated for the past 3 years. It will be shown that using the BGV the average transverse beam size can be obtained with a statistical accuracy of better than 5µm (for a gaussian beam with a σ of 200µm). This precision is obtained with an integration time of less than one minute. In addition, the BGV measures the size of individual bunches with a statistical accuracy of better than 5% within 5 minutes. The results obtained from all the data gathered over the past 3 years will be presented and compared to measurements from other beam profile monitors. Some ideas for improvements for the final HL-LHC instrument will also be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW084

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paper received ※ 10 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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WEPGW090

Emittance Evolution of Low Energy Antiproton Beams in the Presence of Deceleration and Cooling

electron, proton, antiproton, closed-orbit

2697

J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
C. Carli, B. Dupuy, D. Gamba
CERN, Geneva, Switzerland
J.R. Hunt, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The commissioning of the Extra Low Energy Antiproton (ELENA) ring has been completed before the start of the second long shutdown (LS2) at CERN. First beams to an experiment in a new experimental zone have as well already been delivered. ELENA will begin distributing 100 keV cooled antiproton beams to all antimatter experiments in 2021. This contribution presents measurements made using a novel scraping algorithm capable of determining the emittance of non-Gaussian beams in the presence of dispersive effects. The emittance is sampled during various sections of the ELENA deceleration cycle, investigating the efficiency of the electron cooler and extracting additional information from the beam. The electron cooler is shown to effectively reduce the transverse phase space after blow-up during deceleration. The beam is characterised before extraction for the purpose of tracking and optimisation of the new electrostatic transfer lines currently being installed. Finally, the application of the scraping algorithm to other machines with a scraper located in a dispersive region is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW090

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW105

Measuring Beam Parameters with Solenoid

solenoid, focusing, cathode, experiment

2739

I. Pinayev, Y.C. Jing, D. Kayran, V. Litvinenko, K. Shih, G. Wang
BNL, Upton, Long Island, New York, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We have developed methods of measuring electron beam energy and trajectory including angle and position based on the analysis of beam steering by a solenoid. Beam energy measurement is performed in the straight beamline and is suitable for the beams with substantial energy spread. In this paper, we describe the experimental set-up and the obtained results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW105

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW108

Transverse Uncorrelated Emittance Diagnostic for Magnetized Electron Beams

electron, diagnostics, simulation, cathode

2745

M.S. Stefani
ODU, Norfolk, Virginia, USA
F.E. Hannon
JLab, Newport News, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. In this paper, a new diagnostic is described with the purpose of studying transverse magnetized beam properties. The device is a modification to the classic pepper-pot, used in this novel context to measure the uncorrelated components of transverse emittance in addition to the typical effective emittance. The limitations of traditional methods are discussed, and simulated demonstrations of the new technique shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW108

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPRB008

Design Study of High Gradient Compact S-band TW Accelerating Structure for the ThomX LINAC Upgrade

linac, HOM, electron, vacuum

2807

M. El Khaldi, M. Alkadi, C. Bruni, L. Garolfi, A. Gonnin, H. Monard
LAL, Orsay, France

ThomX is a Compton source project in the range of the hard X rays (45/90 keV). The machine is composed of a 50/70 MeV injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a Fabry-Perot resonator. The final goal is to provide an X-rays average flux of 10¹²-10¹³ ph/s. A demonstrator was funded and is being built on the Orsay university campus. The S-band injector Linac consists of 2.5 cell photocathode RF gun and a TW accelerating section. During the commissioning phase, a standard LIL S-band accelerating section is able to achieve around 50 MeV corresponding to around 45 keV X-rays energy. Since the maximum targeted X-ray energy is 90 keV, the development of a new S-band accelerating section, intended to replace the LIL structure, will provide an electron beam energy of 70 MeV. This requires essentially the development of more reliable high gradient compact S band accelerating section. Such design is tailored for high gradient operation, low breakdown rates. We present here the RF design of the LINAC upgrade and the performances obtained in terms of beam dynamics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB008

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paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB027

Electromagnetic Design and Characterization of an S-band 3-Cell RF Accelerating Cavity

cavity, simulation, electron, acceleration

2867

G.R. Montoya Soto
Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
C. Duarte Galván, C.A. Valerio
ECFM-UAS, Culiacan, Sinaloa, Mexico
B. Yee-Rendón
JAEA/J-PARC, Tokai-mura, Japan

An S-Band (2998 MHz) RF cavity to accelerate electrons was developed taking into account the beam space charge, the relativistic change in velocity of the low energy beam particle distribution through the cavity and the emittance growth. The electromagnetic design and geometry optimization were done using the codes Poisson Superfish and CST Studio. In addition, beam dynamics simulations were done using the program Travel to optimize the emittance and take into account the space charge effect. The machining was done in a CNC machining center. Measurements of the cavity resonance frequencies were carried out and compared with the obtained by the simulations with good agreement between them.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB027

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paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPRB072

Ultra-High Gradient Short RF Pulse Gun

gun, electron, cathode, brightness

2987

S.P. Antipov, P.V. Avrakhov, S.V. Kuzikov, A. Liu
Euclid TechLabs, LLC, Solon, Ohio, USA
G. Ha, J.G. Power
ANL, Argonne, Illinois, USA

Funding: DOE SBIR DE-SC0018709
High brightness beams enable novel applications like x-ray free electron lasers and ultrafast electron microscopes. High brightness beams essentially consist of a large number of electrons in a small phase space volume, i.e. a high peak current. When such beams are generated from the cathode, there is a strong space charge force, which elongates the bunch and reduces its brightness. An optimal solution is to raise the accelerating voltage in the gun. However, the maximum gradient is limited by the effects of RF breakdown. The probability of RF breakdown is reduced as the RF pulse length decreases. We present a development of an electron photoinjector operating with short RF pulse, 10 ns scale. We have designed an X-band gun including the RF design, beam quality optimization, and engineering. The gun will be fed by 10 ns, 300 MW RF pulse generated at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. We also manufactured an aluminum prototype and measured its microwave properties, most importantly, fill time. The proposed high brightness beam source can be used as the main beam in wakefield accelerators. It will find commercial applications in ultrafast electron diffraction and microscopy systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB072

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paper received ※ 21 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPRB116

X-ray Pinhole Camera for Emittance Measurements in Solaris Storage Ring

storage-ring, photon, radiation, diagnostics

3084

A. Kisiel, A.M. Marendziak, M. Ptaszkiewicz, A.I. Wawrzyniak
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

X-ray pinhole camera is widely used system for the transverse beam profile measurement and emittance feedback. However this method is predominantly applied to the middle and high energy storage rings. At Solaris storage ring with the nominal energy of 1.5 GeV, the design of the beamline was modified to provide sufficient X-ray photon flux for proper imaging. The successful installation and commissioning of the X-ray pinhole beamline allows now to measure the emittance and helps in proper 3rd harmonic cavities tuning against the coupled bunch mode instabilities. The paper describes the design details, simulations and measurement results obtained during the beamline operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB116

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS011

Intra-Beam Scattering Effect in the SOLEIL Storage Ring Upgrade

lattice, coupling, simulation, cavity

3106

A. Vivoli, A. Bence, P. Brunelle, A. Gamelin, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

As the work on the design of the upgrade of SOLEIL storage ring advances, the study of the impact of Intra-Beam Scattering (IBS) on the equilibrium emittance is also progressing, showing a significant contribution of this effect. Different measures can be taken to mitigate the emittance dilution, like operating the machine with full transverse coupling and using harmonic cavities to increase bunch length. The calculation of the IBS effect needs then to take into account the different beam dynamics and its effect on the particle distribution. In this paper the current state of the ongoing study is presented, reporting on the results obtained for the different options considered, and comparing the results of different codes and their implicit assumptions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS011

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPTS013

The Cooling Effect of Beam Self-Fields on the Photocathode Surface in High Gradient RF Injectors

cathode, laser, electron, space-charge

3112

Y. Chen, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany

The intrinsic slice emittance of the emitted electrons on the photocathode surface at each moment during the transient photoemission process depends on the transverse size of the slice and the mean kinetic energy of the electrons within the slice. The latter relies on the surface barrier potentials of the cathode material at a fixed wavelength of the incident light, and is thus significantly influenced by the presence of strong rf and beam self-fields at / close to the cathode surface. This is, in particular, the case in high brightness injectors for modern free electron lasers. In this article, the beam self-fields are determined in a self-consistent approach, based on which improved transverse and temporal emission distributions are obtained. The nonlinear correlations of the intrinsic surface slice emittance within the bunch are shown for multiple bunch charges. A peak to peak variation of the intrinsic surface emittance is estimated as 30\% for the highest charge-density case considered in this paper. An overall reduction of the average intrinsic emittance is computed as 10\% accordingly. The cooling effect on the cathode surface is enhanced as the local space-charge density rises. Furthermore, the impacts of the cooling effect on downstream beam qualities are demonstrated through particle tracking simulations based on the injector setup at the Photo Injector Test Facility at DESY in Zeuthen (PITZ).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS013

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paper received ※ 27 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPTS020

Development of 6D Particle Tracking Code for Particle Therapy System

synchrotron, acceleration, multipole, operation

3138

Y. Nakashima, K. Miyata
Hitachi Ltd., Ibaraki-ken, Japan

For achieving required specifications of a particle therapy system such as beam profile and beam current, it is important to tune system operation parameters to appropriate values before commissioning. We are developing 6d particle tracking code to analyze whole the through beam motion in a synchrotron from multiturn injection to the RF-knock out extraction for the precise tuning. The code includes effects of multipole magnetic fields and space charge effect. We report on the implementation of the code and discuss about the simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS020

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPTS022

Stability Tune Diagram of a High-Intensity Hadron Ring

resonance, space-charge, lattice, betatron

3141

H. Okamoto, K. Kojima, Y. Tokashiki
HU/AdSM, Higashi-Hiroshima, Japan

To date, the optimum operating point of a high-intensity hadron ring has been determined on the basis of the conventional incoherent picture. It is generally chosen on the tune diagram such that the so-called "incoherent tune spread" of a stored beam does not overlap with low-order "single-particle resonance" lines. We here propose a new approach to construct the stability tune diagram on the basis of the self-consistent coherent picture. The betatron resonance condition recently conjectured from one-dimensional Vlasov predictions is employed for this purpose, which predicts the existence of twice as many resonance stop bands as expected from the well-known incoherent resonance condition at high beam density *,**. The proposed general rules for the stability-chart construction are very simple and free from any model-dependent unobservables like space-charge-depressed incoherent tunes. As an example, we apply the present rules to the lattice of the rapid cycling synchrotron at J-PARC and explain why the operating bare tunes of this machine have been chosen slightly below 6.5 in both transverse directions.
* K. Ito et al., Phys. Rev. Accel. Beams 20, 064201 (2017).
** H. Okamoto and K. Yokoya, Nucl. Instrum. Meth. A 482, 51 (2002).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS022

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paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS028

Transverse-Longitudinal Coupling for Harmonic Generation and Bunch Length Manipulation

bunching, coupling, lattice, storage-ring

3160

X.J. Deng, W.-H. Huang, C.-X. Tang, Y. Zhang
TUB, Beijing, People’s Republic of China
A. Chao
SLAC, Menlo Park, California, USA

A general harmonic generation and bunch length manipulation scheme using transverse-longitudinal coupling is presented. The method makes use of the freedom in projecting the three beam eigen-emittances into different physical dimensions. A realization of this coupling lattice, a PEHG variant, is given as an example. For the purpose of harmonic generation and bunch compression, this method is advantageous when the transverse emittance is small. The combination with sawtooth waveform modulation is proposed to boost the bunching further. Transverse-longitudinal coupling in storage rings are briefly discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS028

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS039

Momentum Slip-Stacking in CERN SPS for the Ion Beams

simulation, cavity, optics, operation

3184

T. Argyropoulos, T. Bohl, A. Lasheen, G. Papotti, D. Quartullo, E.N. Shaposhnikova
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) project at CERN aims at doubling the total intensity of the lead ion beam for the High-Luminosity (HL) LHC. Achieving this goal requires using momentum slip-stacking in the SPS, the LHC injector. Slip-stacking will be applied on an intermediate energy plateau to interleave two batches, reducing the bunch spacing from 100 ns to 50 ns and thus increasing the total number of bunches injected into the LHC. Realistic macro-particle simulations, with the present SPS impedance model are used to study and design this complicated beam manipulation. Slip-stacking can be tested experimentally only after the upgrade of the SPS 200 MHz RF system, in 2021. Preliminary, slip-stacking related beam measurements were performed at the end of 2018. In this paper both macro-particle simulations and beam measurements are reported with emphasis given on optimisation of the process, crucial to achieve the required HL-LHC parameters (bunch lengths, beam losses).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS039

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPTS041

Coupling and Space Charge Studies at the CERN PSB

resonance, optics, coupling, space-charge

3192

F. Asvesta
NTUA, Athens, Greece
F. Antoniou, H. Bartosik, G.P. Di Giovanni, Y. Papaphilippou
CERN, Meyrin, Switzerland

In the nominal optics of the CERN PS-Booster (PSB), the fourth order coupling resonance is excited by space charge (Montague resonance) due to the same integer tune values. This resonance can be avoided by changing the tunes to different integers. A new PSB optics is presented and emittance measurements crossing the coupling resonance for the nominal and the new optics are shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS041

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paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS042

Detailed Characterisation of the LEIR Intensity Limitations for a Pb Ion Beam

resonance, simulation, injection, sextupole

3196

Á. Saá Hernández, H. Bartosik, N. Biancacci, S. Hirlaender, D. Moreno Garcia, M. Zampetakis
CERN, Meyrin, Switzerland

The equilibrium emittance of the Pb beam in the CERN Low Energy Ion Ring (LEIR) results from the interplay of electron cooling and heating processes, as intra-beam scattering and space charge. In this paper we present the measurements of the emittance evolution as a function of intensity, working point and resonance excitation, and compare them with the simulations of the heating processes. Optimum settings for normal and skew sextupoles have been found for the compensation of resonances excited by the lattice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS042

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paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS046

Monitoring and Modelling of the LHC Emittance and Luminosity Evolution in 2018

luminosity, operation, experiment, proton

3212

S. Papadopoulou, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, N. Karastathis, S. Kostoglou, Y. Papaphilippou, G. Trad
CERN, Geneva, Switzerland

Operating at 6.5 TeV, the LHC surpassed the expectations and delivered an average of 66 fb−1 integrated luminosity to the two high luminosity experiments ATLAS and CMS by the end of 2018. In order to provide a continuous feedback to the machine coordination for further optimizing the performance, an automated tool for monitoring the main beam parameters and machine configurations, has been devised and extensively used. New features like the coupling between the two planes and effects of noise, were added to the numerical model used since 2016 to calculate the machine luminosity. Estimates, based both on simulations and on observed beam parameters, were reported fill-by-fill as well as in overall trends during the year. Highlights of the observations including the observed additional emittance blow up (on top of IBS, SR and elastic scattering) as well as additional losses (on top of the expected proton burn off) are presented for the 2018 data. Finally, cumulated integrated luminosity projections from the model for the entire 2018 data based on different degradation mechanisms are compared also with respect to the achieved luminosity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS046

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paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS057

Recent Studies of the Resonances at a Cell Tune of 0.25 Using the Ibex Paul Trap

resonance, experiment, simulation, space-charge

3255

L. Martin, S.L. Sheehy
JAI, Oxford, United Kingdom
D.J. Kelliher
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

We use the IBEX linear Paul trap to study the resonance at a cell tune of \frac{1}{4} with both equal and unequal transverse tunes, at a range on intensities. We compare this experimental result to simulation using the PIC code Warp. We find that the experimental result differs from the simulation, which may be explained by the ion loss in the IBEX experiment, which more closely replicates a real accelerator. Knowledge of the tune corresponding to greatest beam loss is important for the design of future high intensity machines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS057

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paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPTS069

The Effects of Stochastic Space Charge in High Brightness Photolectron Beamlines for Ultrafast Electron Diffraction

space-charge, simulation, electron, cathode

3283

M.A. Gordon, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
J.M. Maxson
Cornell University, Ithaca, New York, USA
J.M. Maxson
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by the U.S. National Science Foundation under award PHY-1549132, the Center for Bright Beams.
As we move to ultra-high brightness photocathodes and ultra-cold beams, we may become more sensitive to stochastic, point-to point effects such as disorder induced heating and the Boersch effect, given the failure of Debye screening. In this study, we explore the effects of stochastic scattering. Modern beam dynamics codes often approximate point to point interactions with a potential created by smoothing the charge over space, removing sensitivity to stochastic effects. This approximation is often used in beamline optimization, because it is much faster. We study the limits of validity of this approximation. In particular, we will simulate effects of stochastic space charge on a high brightness photoemission beamline, an ultrafast electron diffraction beamline with a photocathode temperature of 5 meV with a final beam energy of 225 keV. Emittance dilution in the transverse plane and transverse beam size relative to smooth space charge simulations will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS069

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS072

Application of Bayesian Inference in Accelerator Commissioning of FRIB

diagnostics, MMI, experiment, coupling

3289

Y. Hao, L.M. Neufcourt
FRIB, East Lansing, Michigan, USA

We will report the preliminary application of the Bayesian Inference of the unknown parameters of accelerator model using the FRIB commissioning data. The inference result not only indicates the value of the unknown parameter, but also the confidence of adopting the value. The Bayesian approach provides an alternative method to understand the difference between accelerator model and the hardware and may help achieving ultimate beam parameters of FRIB.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS072

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS079

Analysis of Particle Noise in a Gridless Spectral Poisson Solver for Symplectic Multiparticle Tracking

space-charge, focusing, plasma, simulation

3304

C.E. Mitchell, J. Qiang
LBNL, Berkeley, California, USA

Funding: This work was was supported by the Director, Office of Science, Office of High Energy Physics, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Gridless symplectic methods for self-consistent modeling of space charge in intense beams possess several advantages over traditional momentum-conserving particle-in-cell methods, including the absence of numerical grid heating and the presence of an underlying multi-particle Hamiltonian. Despite these advantages, there remains evidence of irreversible emittance growth due to numerical particle noise. For a class of such algorithms, a first-principles kinetic model of the numerical particle noise is obtained and applied to gain insight into noise-induced entropy growth and thermal relaxation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS079

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS081

An Analytic Approach to Emittance Growth from the Beam-Beam Effect with Applications to the LHeC

proton, electron, GUI, collider

3307

E.A. Nissen
JLab, Newport News, Virginia, USA
D. Schulte
CERN, Meyrin, Switzerland

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, world-wide license to publish or reproduce this manuscript.
In colliders with asymmetric rigidity such as the proposed Large Hadron electron Collider, jitter in the weaker beam can cause emittance growth via coherent beam-beam interactions. The LHeC in this case would collide 7 TeV protons on 60 GeV electrons, which can be modeled using a weak-strong model. In this work we estimate the proton beam emittance growth by separating out the longitudinal angular kicks from an off-center bunch interaction and produce an analytic expression for the emittance growth per turn in systems like the LHeC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS081

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paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS088

Integration of Cavity Design and Beam Dynamics Simulation Using the Parallel IMPACT and the ACE3P Codes

cavity, simulation, electron, gun

3317

J. Qiang, D.A. Bizzozero
LBNL, Berkeley, California, USA
L. Ge, Z. Li, C.-K. Ng, L. Xiao
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and DE-AC02-76SF00515,
The 3D parallel code suite IMPACT has been extensively used in the beam dynamics study of photoinjectors while the 3D parallel code ACE3P has been extensively used in the RF cavity design. In this paper, we propose integrating the ACE3P cavity design and the IMPACT beam dynamics simulation into a single work flow. Such a workflow enables efficient simulation of 3D effects(e.g. RF coupler) on high performance computers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS088

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paper received ※ 07 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS093

Emittance Preservation for LCLS-II-HE Project

electron, lattice, laser, space-charge

3333

J. Wu, T.O. Raubenheimer, M.D. Woodley
SLAC, Menlo Park, California, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
A small transverse slice emittance at the undulator entrance is essential for high performance of the free electron laser. To achieve this, preservation of the phase space density of the electron bunch during acceleration and compression is absolutely necessary. The LCLS-II-HE is designed to transport a 100 pC bunch with an emittance of ~0.3 mm-mrad with minimal emittance dilution. However, in simulations starting from a normalized emittance on the order of 0.1 mm-mrad, the emittance growth is significant. In this paper, the sources of emittance growth are studied along the accelerator, in particular, around the laser-heater, the two bunch compressors. We have investigated mechanisms of emittance growth such as space charge, coherent synchrotron radiation, chromatic aberration, and spurious dispersion. Due to the extremely small emittance from the injector, 3-D space charge effect is important to determine the space charge dominated region and emittance dominated region. With this understanding, emittance preservation schemes are proposed. Studies are carried out with IMPACT simulation code, as well as ASTRA and ELEGANT.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS093

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paper received ※ 23 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPTS094

Generation High-Charge of Flat Beams at the Argonne Wakefield Accelerator

solenoid, electron, quadrupole, experiment

3337

T. Xu, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
M.E. Conde, G. Ha, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: This work is supported by the U.S. DOE contracts No. DESC0017750, DE-SC0018656 with NIU, and No. DE-AC02-06CH11357 with ANL.
Beams with large transverse emittance ratios (flat beams)have received renewed interest for their possible applications in future linear colliders and advanced accelerators. A flat beam can be produced by generating a magnetized beam and then repartitioning its emittance using three skew quadrupoles. In this paper, we report on the experimental generation of∼1nC flat beams at the Argonne WakefieldAccelerator (AWA). The emittance ratio of the flat beam is demonstrated to be continuously variable by adjusting the magnetic field on the cathode.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS094

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPTS108

Emittance Exchange in MICE

experiment, collider, simulation, factory

3378

C. Brown
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom

Funding: STFC, NSF, DOE, INFN, CHIPP and more
The Muon Ionization Cooling Experiment, MICE, has demonstrated transverse emittance reduction through ionization cooling. Transverse ionization cooling can be used either to prepare a beam for acceleration in a neutrino factory or for the initial stages of beam cooling in a muon collider. Later stages of ionization cooling in the muon collider require the longitudinal emittance to be manipulated using emittance exchange and reverse emittance exchange, where emittance is exchanged from and to longitudinal phase space respectively. A wedge absorber within the MICE cooling channel has been used to experimentally demonstrate reverse emittance exchange in ionization cooling. Parameters for this test have been explored in simulation and applied to experimental configurations using a wedge absorber when collecting data in the MICE beam. This analysis of reverse emittance exchange is presented in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS108

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THYYPLM3

High-Charge Injector for on-Axis Injection Into A High-Performance Storage Ring Light Source

booster, injection, synchrotron, storage-ring

3423

K.C. Harkay, I.A. Abid, T.G. Berenc, W. Berg, M. Borland, A.R. Brill, D.J. Bromberek, J.M. Byrd, J.R. Calvey, J. Carvelli, J.C. Dooling, L. Emery, T. Fors, G.I. Fystro, A. Goel, D. Hui, R.T. Keane, R. Laird, F. Lenkszus, R.R. Lindberg, T.J. Madden, B.J. Micklich, L.H. Morrison, S.J. Pasky, V. Sajaev, N. Sereno, H. Shang, T.L. Smith, J.B. Stevens, Y. Sun, G.J. Waldschmidt, J. Wang, U. Wienands, K.P. Wootton, A. Xiao, B.X. Yang, Y. Yang, C. Yao
ANL, Argonne, Illinois, USA
A. Blednykh
BNL, Upton, Long Island, New York, USA
A.H. Lumpkin
Fermilab, Batavia, Illinois, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Next-generation, high-performance storage ring light sources based on multibend achromat optics will require on-axis injection because of the extremely small dynamic aperture. Injectors will need to supply full-current bunch replacement in the ring with high single-bunch charge for swap-out. For upgrades of existing light sources, such as the Advanced Photon Source Upgrade (APS-U), it is economical to retain the existing injector infrastructure and make appropriate improvements. The challenges to these improvements include achieving high single-bunch charge in the presence of instabilities, beam loading, charge stability and reliability. In this paper, we discuss the rationale for the injector upgrades chosen for APS-U, as well as backup and potential alternate schemes. To date, we have achieved single-bunch charge from the injectors that doubles the original design value, and have a goal to achieve about three times the original design value.

Slides THYYPLM3 [1.499 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THYYPLM3

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPGW006

Avoiding Emittance Degradation When Transferring the Beam From and to a Plasma-Wakefield Stage

plasma, acceleration, focusing, quadrupole

3594

A. Chancé, P.A.P. Nghiem
CEA-IRFU, Gif-sur-Yvette, France
X. Li
DESY Zeuthen, Zeuthen, Germany

Funding: European Union’s Horizon 2020 research and innovation programme under grant agreement No. 653782.
The plasma-wakefield acceleration technique is known to provide a very strong accelerating gradient (GV/m), up to three orders of magnitude higher than the conventional RF acceleration technique. The drawback is a relatively higher energy spread and especially a huge beam divergence at the plasma exit, leading to an irremediable and strong emittance degradation right after its extraction from the plasma for transferring it to an application or another plasma stage. In this article, we determine the criteria to be achieved so as to minimize this emittance growth after pointing out all the parameters involved in its mechanism. Then the plasma down ramp profile is studied in a typical configuration of the EuPRAXIA project at 5 GeV. It turns out that no specific profile is needed. For minimizing emittance growth at beam extraction, it is enough to optimize the ramp length so that the Twiss parameter γ is minimized. Finally the design of an optimal transfer line allows showing that the emittance growth can be contained to less than 10% in realistic conditions when transferring the beam to a free electron laser.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW006

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paper received ※ 09 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPGW012

Wake-T: A Fast Particle Tracking Code for Plasma-Based Accelerators

plasma, simulation, electron, laser

3601

A. Ferran Pousa, R.W. Aßmann, A. Martinez de la Ossa
DESY, Hamburg, Germany
A. Ferran Pousa
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The design and study of plasma-based accelerators relies typically on costly 3D Particle-In-Cell (PIC) simulations due to the complexity of the laser-plasma and beam-plasma interactions. However, under certain assumptions, more efficient and simple models can be implemented to describe the dynamics of the accelerated beams. Wake-T (Wakefield particle Tracker) is a new code for analytical and numerical particle tracking in plasma-based accelerators which is orders of magnitude faster than conventional PIC codes. This allows for fast parameter scans and is well suited for the initial design and optimization of these novel accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW012

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paper received ※ 24 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPGW043

Conceptual design of a MeV Ultrafast Electron Diffraction Based on 1.4 Cell RF Gun

electron, gun, cathode, laser

3679

J.J. Li, H.M. Chen, K. Fan, Y. Song, P. Yang, Y.T. Yang
HUST, Wuhan, People’s Republic of China

Ultrafast Electron Diffraction (UED) is a powerful tool to investigate the dynamic structure with temporal scale of 100 femtoseconds and spatial scale of atomic length. To achieve high quality diffraction patterns, the transverse emittance and the longitudinal length of electron bunches should be reduced. MeV UED, using photocath-ode RF gun instead of traditional DC gun, is being developed to produce high quality electron bunches with lower emittance and shorter length. We are developing a MeV UED facility based on a 1.4 cell photocathode RF gun that can provide higher acceleration gradient at Huazhong University of Science and Technology. In this paper, the conceptual design of the MeV UED is pro-posed with typical parameters of the system, as well as the ASTRA simulation results of optimization.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW043

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paper received ※ 11 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPGW067

Progress Towards a Single-Shot Emittance Measurement Technique at AWAKE

quadrupole, plasma, dipole, electron

3742

J. Chappell, D.A. Cooke, L.C. Deacon, S. Jolly, F. Keeble, M. Wing
UCL, London, United Kingdom

Externally injected electrons are captured and accelerated in the plasma wake of a self-modulated proton beam at the Advanced Wakefield Experiment (AWAKE) at CERN. The energy distribution of the accelerated electron beam is measured using a dipole spectrometer in combination with a scintillator screen, with two upstream quadrupoles providing energy-dependent focusing. Measuring the vertical beam size variation with horizontal position along the scintillator screen, and therefore energy, results in an effective quadrupole scan permitting single shot vertical geometric emittance measurements. Limitations of the method due to effects such as imperfect beam focusing and finite resolution are explored via simulations using the beam tracking code BDSIM.
james.chappell.17@ucl.ac.uk

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW067

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPGW087

Transverse Jitter Tolerance Issues for Beam-Driven Plasma Accelerators

plasma, acceleration, FEL, electron

3774

G.R. White, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: Work supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.
Transverse jitter tolerances are considered for beam-driven plasma accelerators. A simple model for jitter transfer from the drive to witness beam is developed and concrete examples are studied for: high-brightness witness bunch injectors; high-energy boosters for FEL’s; and future Linear Colliders. Compared with an existing PWFA driver facility ([*,**]), the calculated tolerances are 18X ’ 170X tighter than achievable, even considering any upgrades with existing technology.
* Nature 445 741 Feb 2007, Nature 515, Nov. 2014
** FACET-II Technical Design Report, SLAC-R-1072, "The FLASHForward facility at DESY", NIMA Oct., 2015

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPGW088

Transformer Ratio Measurements from Ramped Beams in the Plasma Blowout Regime using Emittance Exchange

plasma, wakefield, experiment, acceleration

3778

R.J. Roussel, G. Andonian, W.J. Lynn, J.B. Rosenzweig
UCLA, Los Angeles, USA
M.E. Conde, D.S. Doran, G. Ha, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
J. Seok
UNIST, Ulsan, Republic of Korea

Funding: Work is supported by DOE contract DE-SC0017648.
We present initial measurements from a UCLA-Argonne Wakefield Accelerator collaborative plasma wakefield acceleration (PWFA) experiment aimed at demonstrating the dependence of transformer ratio on longitudinal beam shape. The transformer ratio or the ratio between the maximum acceleration of the witness and the maximum deceleration of the drive beam, is key to a mature, beam-based, plasma wakefield accelerator design. Utilizing the unique capabilities of the emittance exchange (EEX) beamline, we may obtain transformer ratios in excess of six in PWFA. We present the experimental beamline design, relevant beam diagnostics and explore preservation of the longitudinal beam profile.

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB022

Sensitivity Analysis of Feedforward Beam Current Compensation for Improved Beam Loading Robustness

cavity, controls, injection, simulation

3850

D. Mihailescu Stoica, D. Domont-Yankulova
RMR, TU Darmstadt, Darmstadt, Germany
D. Domont-Yankulova, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany
H. Klingbeil, D.E.M. Lens
GSI, Darmstadt, Germany

The planned SIS100 heavy ion synchrotron at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany will possess twenty ferrite accelerating cavities in its final stage of extension. During the intended acceleration cycles, the cavities will encounter significant beam loading effects, which have to be handled by the control systems. As both the generator- and beam-current act on the same system input, a feedforward disturbance compensation can be a promising approach to improve beam qualities and suppress instabilities induced by the beam current. Particle tracking simulations, incorporating twenty ferrite cavities and their attached LLRF control systems, are performed to analyse the sensitivity of the beam quality with respect to errors in the feedforward beam current compensation. The main focus lies on the time after injection from a pre-accelerator, where most cavities in the SIS100 do not provide any gap voltage and thus are particularly sensitive to induced voltages by beam currents if the cavities are not or only partly short-circuited.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB022

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paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB067

Time Varying RF Phase Noise for Longitudinal Emittance Blow-Up

synchrotron, operation, proton, extraction

3954

S.C.P. Albright
CERN, Geneva, Switzerland
D. Quartullo
Sapienza University of Rome, Rome, Italy

RF phase noise was shown to be effective for controlled longitudinal emittance blow-up in the Proton Synchrotron Booster (PSB) at CERN during beam tests in 2017, with further developments in 2018. At CERN, RF phase noise is used operationally in the Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC). In this paper we show that it is suitable for operation with a variety of beam types in the PSB. In the PSB the synchrotron frequency changes by approximately a factor 4 during the 500 ms acceleration ramp, requiring large changes in the frequency band of the noise. During 2018, a new method of calculating the noise parameters has been demonstrated, which gives upper and lower bounds to the noise frequency band that are smoothly varying through the ramp. The new calculation method has been applied to operational beams accelerated in both single and double RF harmonics, the final results are presented here.

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paper received ※ 29 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPTS009

High-Current Emittance Measurements at MAMI

quadrupole, electron, experiment, simulation

4121

S. Heidrich, K. Aulenbacher, M. Dehn, P. Heil
IKP, Mainz, Germany
M.W. Bruker
HIM, Mainz, Germany

Funding: Work supported by BMBF-Verbundforschung Verbundprojekt 05H2015UMRB1, R&D Beschleuniger (Positronenquellen)
The effects of high beam currents and different types of electron sources on the emittance of the beam at the 3.5 MeV beamline of the Mainzer Microtron MAMI were observed. A thermionic BaO source and a GaAs-based photo-source that allows spin polarization were used. In order to measure the beam size, a new type of wire scanner was utilized. The results show maximum normalized emittance values in the order of a few hundred nmrad for both sources, which lies distinctly within the acceptance of the higher energy stages of the accelerator.

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS034

Design and Progress of Mechanical Support in HEPS

alignment, simulation, storage-ring, synchrotron

4180

C.H. Li, Y. Jiao, M.X. Li, H. Wang, Z. Wang, L. Wu, N. Zhou
IHEP, Beijing, People’s Republic of China

HEPS is a new generation synchrotron facility on construction with very low emittance. Stringent requirements are proposed to the design of mechanical support. The alignment error between girders should be less than 50μm. Based on that, the adjusting resolution of the girder are required to be less than 5μm in both transverse and vertical directions. Besides, the Eigen frequency of magnet & girder assembly should be higher than 54Hz to avoid the amplification of ground vibrations. To fulfill these requirements, studies on mechanical support design is now being carried out in HEPS. This paper will describe the design and progress of those work.

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS046

The Limited B-Field Integral of Superconducting Longitudinal Gradient Bend Magnet

simulation, storage-ring, synchrotron-radiation, radiation

4213

C. Chen, L. Wang, H.R. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The National Synchrotron Radiation Laboratory (NSRL) is planning a fourth generation diffraction-limited light source–Hefei Advanced Light Source (HALS), it is based on a seven-bend achromat lattice providing an ultralow natural emittance of 34 pm rad. The emittance can be even lower with the use of longitudinal gradient bends (LGBs) and anti-bends (ABs). The designed energy for HALS is 2.4 GeV, superconducting LGB might be employed instead of normal bending magnet since it can improve radiated beam critical energy to hard x-ray regions without using up any straight sections. To get a peak field about 6 T and small B-field profile full width half maximum, SLS-2 type LGB is considered. In this paper, the limited B-field integral (along the beam path) is trying to be find with some restrictions.

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paper received ※ 12 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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