IPAC2021 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOXA03	Sirius Commissioning Results and Operation Status	MMI, storage-ring, alignment, injection	13
	L. Liu, M.B. Alves, A.C.S. Oliveira, X.R. Resende, F.H. de Sá LNLS, Campinas, Brazil
	Sirius is a 4th generation 3 GeV synchrotron light source that has just finalized the first commissioning phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. This paper describes the main Accelerator Physics issues faced during the storage ring commissioning, methods that were used to work them out and the current operation status of the machine.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA03
About •	paper received ※ 20 May 2021 paper accepted ※ 10 June 2021 issue date ※ 16 August 2021
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MOPAB001	Power Deposition in Superconducting Dispersion Suppressor Magnets Downstream of the Betatron Cleaning Insertion for HL-LHC	proton, collimation, dipole, simulation	37
	A. Waets, C. Bahamonde Castro, E. Belli, R. Bruce, N. Fuster-Martínez, A. Lechner, A. Mereghetti, S. Redaelli, M. Sabaté-Gilarte, E. Skordis CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project The power deposited in dispersion suppressor magnets downstream of the Large Hadron Collider (LHC) betatron cleaning insertion is governed by off-momentum particles scattered out of the primary collimators. In order to mitigate the risk of magnet quenches during periods of short beam lifetime in future High-Luminosity (HL-LHC) operation, new dispersion suppressor (DS) collimators are considered for installation (one per beam). In this paper, we present FLUKA simulations for both protons and Pb ions at 7 TeV, predicting the power deposition in the DS magnets, including the new higher-field dipoles 11T which are needed to integrate the collimator in the cold region next to the cleaning insertion. The simulated power deposition levels for the adopted HL-LHC collimator configuration and settings are used to assess the quench margin by comparison with the present estimated quench levels.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB001
About •	paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 16 August 2021
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MOPAB002	Risk of Halo-Induced Magnet Quenches in the HL-LHC Beam Dump Insertion	proton, insertion, collimation, betatron	41
	J.B. Potoine, A. Apollonio, E. Belli, C. Bracco, R. Bruce, M. D’Andrea, R. García Alía, A. Lechner, G. Lerner, S. Morales Vigo, S. Redaelli, V. Rizzoglio, E. Skordis, A. Waets CERN, Meyrin, Switzerland F. Wrobel IES, Montpellier, France
	Funding: Research supported by the HL-LHC project After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB002
About •	paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 22 August 2021
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MOPAB003	Machine Learning Analysis of Electron Cooler Operation for RHIC	luminosity, electron, scattering, GUI	45
	X. Gu, A.V. Fedotov, D. Kayran BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A regression machine learning algorithm was applied to analyze the operation data of RHIC with electron cooler LEReC during the 2020 physics run. After constructing a black-box surrogate model from the XGBoost algorithm and plotting their partial dependency plots for different operation parameters, we can find the effects of an individual parameter on the RHIC luminosity and optimize it accordingly offline.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB003
About •	paper received ※ 14 May 2021 paper accepted ※ 25 May 2021 issue date ※ 11 August 2021
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MOPAB005	Studies for an LHC Pilot Run with Oxygen Beams	target, luminosity, MMI, proton	53
	R. Bruce, R. Alemany-Fernández, H. Bartosik, M.A. Jebramcik, J.M. Jowett, M. Schaumann CERN, Geneva, Switzerland
	Motivated by the study of collective effects in small systems with oxygen-oxygen (O-O) collisions, and improvements to the understanding of high-energy cosmic ray interactions from proton-oxygen (p-O) collisions, a short LHC oxygen run during Run 3 has been proposed. This article presents estimates for the obtainable luminosity performance in these two running modes based on simulations of a typical fill. The requested integrated luminosity, projected beam conditions, data-taking and commissioning times are considered and a running scenario is proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB005
About •	paper received ※ 17 May 2021 paper accepted ※ 25 May 2021 issue date ※ 19 August 2021
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MOPAB008	Exploiting the Beam-Beam Wire Demonstrators in the Next LHC Run 3	octupole, luminosity, experiment, quadrupole	65
	A. Poyet Université Grenoble Alpes, Grenoble, France S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, A. Rossi, G. Sterbini CERN, Geneva, Switzerland K. Skoufaris University of Crete, Heraklion, Crete, Greece
	After the successful experiments performed during the LHC Run 2 with the Beam-Beam Wire demonstrators installed, on Beam 2, in the frame of the HL-LHC project, two of the four wire demonstrators were moved to Beam 1. The objective is to gain operational experience with the wire compensation also on that beam and therefore fully exploit the demonstrators’ potential. This paper proposes a numerical validation of the wire implementation using Run 3 scenarios and explores the optimization of those devices in that respect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB008
About •	paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 11 August 2021
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MOPAB009	Review of the Fixed Target Operation at RHIC in 2020	target, experiment, controls, kicker	69
	C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. As part of the Beam Energy Scan (BES) physics program, RHIC operated in Fixed Target mode at various beam energies in 2020. The fixed target experiment, achieved by scraping the beam halo of the circulating beam on a gold ring inserted in the beam pipe upstream of the experimental detectors, extends the range of the center-of-mass energy for BES. The machine configuration, control of rates, and results of the fixed target experiment operation in 2020 will be presented in this report.
	Poster MOPAB009 [2.913 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB009
About •	paper received ※ 16 May 2021 paper accepted ※ 17 August 2021 issue date ※ 23 August 2021
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MOPAB010	RHIC Beam Energy Scan Operation with Electron Cooling in 2020	luminosity, electron, emittance, experiment	72
	C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. RHIC provided Au-Au collisions at beam energies of 5.75 and 4.59 GeV/nucleon for the physics program in 2020 as a part of the Beam Energy Scan II experiment. The operational experience at these energies will be reported with emphasis on their unique features. These unique features include the addition of a third harmonic RF system to enable a large longitudinal acceptance at 5.75 GeV/nucleon, the application of additional lower frequency cavities for alleviating space charge effects, and the world-first operation of cooling with an RF-accelerated bunched electron beam.
	Poster MOPAB010 [3.523 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB010
About •	paper received ※ 17 May 2021 paper accepted ※ 29 July 2021 issue date ※ 10 August 2021
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MOPAB013	Radiation to Electronics Impact on CERN LHC Operation: Run 2 Overview and HL-LHC Outlook	radiation, luminosity, electron, target	80
	Y.Q. Aguiar, A. Apollonio, F. Cerutti, S. Danzeca, R. García Alía, G. Lerner, D. Prelipcean, M. Sabaté-Gilarte CERN, Geneva 23, Switzerland
	Funding: Research supported by the HL-LHC project After the mitigation measures implemented during Run 1 (2010-2012) and Long Shutdown 1 (LS1, 2013-2014), the number of equipment failures due to radiation effects on electronics (R2E) leading to LHC beam dumps and/or machine downtime has been sufficiently low as to yield a minor impact on the accelerator performance. During Run 2 (2015-2018) the R2E related failures per unit of integrated luminosity remained below the target value of 0.5 events/fb-1, with the sole exception of the 2015 run during which the machine commissioning took place. However, during 2018, an increase in the failure rate was observed, linked to the increased radiation levels in the dispersion suppressors of the ATLAS and CMS experimental insertions, significantly affecting the Quench Protection System located underneath the superconducting magnets in the tunnel. This work provides an overview of the Run 2 R2E events during LHC proton-proton operation, putting them in the context of the related radiation levels and equipment sensitivity, and providing an outlook for Run 3 and HL-LHC operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB013
About •	paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 23 August 2021
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MOPAB016	Small Longitudinal Emittance Setup in Injectors with Gold Beam for Beam Energy Scan in RHIC	emittance, luminosity, extraction, cavity	90
	H. Huang, C.J. Gardner, C. Liu, V. Schoefer, K. Zeno BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In recent years, RHIC physics program calls for gold beam collisions with energies at and lower than the nominal RHIC injection energy. To get shorter bunches at the three higher energies (9.8GeV/c, 7.3GeV/c and 4.75GeV/c), RHIC 28MHz cavities were used. The longitudinal emittance out of injectors needs to fit in the 28MHz cavities in RHIC. At two lower energies (4.6 and 3.85 GeV/c), the 9MHz RF cavities were used, which set different requirements from injectors. Extensive beam studies were carried out to establish needed beam parameters, such as bunch intensities and longitudinal emittances. In general, enough intensity can be provided for all energies within the longitudinal emittance constraint. This paper summarizes the recent injector operation experiences for various energies.
	Poster MOPAB016 [2.641 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB016
About •	paper received ※ 16 May 2021 paper accepted ※ 17 August 2021 issue date ※ 01 September 2021
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MOPAB023	Experimental Test of a New Method to Verify Retraction Margins Between Dump Absorbers and Tertiary Collimators at the LHC	experiment, alignment, beam-losses, emittance	115
	C. Wiesner, W. Bartmann, C. Bracco, R. Bruce, J. Molson, M. Schaumann, C. Staufenbiel, J.A. Uythoven, M. Valette, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Meyrin, Switzerland
	The protection of the tertiary collimators (TCTs) and the LHC triplet aperture in case of a so-called asynchronous beam dump relies on the correct retraction between the TCTs and the dump region absorbers. A new method to validate this retraction has been proposed, and a proof-of-principle experiment was performed at the LHC. The method uses a long orbit bump to mimic the change of the beam trajectory caused by an asynchronous firing of the extraction kickers. It can, thus, be performed with circulating beam. This paper reports on the performed beam measurements, compares them with expectations and discusses the potential benefits of the new method for machine protection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB023
About •	paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 24 August 2021
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MOPAB028	Using Machine Learning to Improve Dynamic Aperture Estimates	simulation, dynamic-aperture, collider, hadron	134
	F.F. Van der Veken, M. Giovannozzi, E.H. Maclean CERN, Geneva, Switzerland C.E. Montanari Bologna University, Bologna, Italy G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	The dynamic aperture (DA) is an important concept in the study of nonlinear beam dynamics. Several analytical models used to describe the evolution of DA as a function of time, and to extrapolate to realistic time scales that would not be reachable otherwise due to computational limitations, have been successfully developed. Even though these models have been quite successful in the past, the fitting procedure is rather sensitive to several details. Machine Learning (ML) techniques, which have been around for decades and have matured into powerful tools ever since, carry the potential to address some of these challenges. In this paper, two applications of ML approaches are presented and discussed in detail. Firstly, ML has been used to efficiently detect outliers in the DA computations. Secondly, ML techniques have been applied to improve the fitting procedures of the DA models, thus improving their predictive power.
	Poster MOPAB028 [1.764 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB028
About •	paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 12 August 2021
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MOPAB031	Development and Operation of Vacuum System for Rapid Cycling Synchrotron to Target Beam Transfer Line of China Spallation Neutron Source	vacuum, target, neutron, proton	145
	J.M. Liu, Y.H. Guan, S.M. Liu, B. Tan, P.C. Wang DNSC, Dongguan, People’s Republic of China H. Dong IHEP, Beijing, People’s Republic of China H.Y. He, T. Huang IHEP CSNS, Guangdong Province, People’s Republic of China
	China Spallation Neutron Source (CSNS) is a major scientific project during the National Eleventh Five-Year Plan. It consists of a negative hydrogen ion linear accelerator, a rapid cycling synchrotron ( RCS), a linac to RCS beam transfer line (LRBT), an RCS to target beam transfer line (RTBT), and a target station. As an important part of CSNS, the RTBT connects the rapid cycling synchrotron and the target window. This paper described the design requirements, technical solutions, and operating conditions of the vacuum system for the CSNS RCS to target beam transfer line. In addition, the fast valve protection system and its verification results were also expounded. The CSNS has been in operation for over three years, during this period, the beam power has been gradually improved from 10KW to 100KW, and the vacuum system for RTBT has been operating stably.
	Poster MOPAB031 [0.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB031
About •	paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 25 August 2021
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MOPAB036	Different Operation Regimes at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)	optics, lattice, electron, storage-ring	163
	A.I. Papash, M. Brosi, E. Huttel, A. Mochihashi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	The KIT storage ring KARA operates in a wide energy range from 0.5 to 2.5 GeV. Different operation modes have been implemented at KARA, so far, the double-bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, different versions of low-compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low-alpha optics has been simulated, tested and implemented in a wide operational range of the storage ring and is now routinely used at 1.3 GeV for studies of beam bursting effects caused by coherent synchrotron radiation in the THz frequency range. Different non-linear effects, in particular residual high-order components of the magnetic field, generated in high-field superconducting wigglers have been studied and cured. Based on good agreement between computer simulations and experiments, a new operation mode at high vertical tune was implemented. The beam performance during user operation as well as at low-alpha regimes has been improved. A specific optic with negative compaction factor was simulated, tested and is in operation.
	Poster MOPAB036 [1.477 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB036
About •	paper received ※ 13 May 2021 paper accepted ※ 08 June 2021 issue date ※ 29 August 2021
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MOPAB037	On Possibility of Alpha-buckets Detecting at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)	storage-ring, optics, synchrotron, electron	167
	A.I. Papash, T. Boltz, M. Brosi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	Computer studies of longitudinal motion have been performed with the objective to estimate the possibility of detection of alpha-buckets at the KIT storage ring KARA (Karlsruhe Research Accelerator). The longitudinal equations of motion and the Hamiltonian were expanded to high order terms of the energy deviation of particles in a beam. Roots of third order equation for three leading terms of momentum compaction factor and free energy independent term were derived in a form suitable for analytical estimations. Averaged quadratic terms of closed orbit distortions caused by misalignment of magnetic elements in a ring lead to orbit lengthening independent of particle energy deviation. Particle transverse excursions were estimated and are taken into account. Simulations have been bench-marked on existing experiments at Metrology Light Source (MLS) in Berlin (Germany) and SOLEIL (France). Parameters of three simultaneous beams and alpha buckets at MLS and SOLEIL have been reproduced with high accuracy. A computer model of KARA was used to predict behavior and the dynamics of possible simultaneous beams in the ring.
	Poster MOPAB037 [1.269 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB037
About •	paper received ※ 11 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021
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MOPAB044	Gas Bremsstrahlung Measurements in the Advanced Photon Source Storage Ring	photon, radiation, detector, injection	193
	J.C. Dooling, A.R. Brill, J.R. Calvey ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357. In the Advanced Photon Source Upgrade storage ring (SR), small-aperture vacuum chambers provide limited conductance for pumping. Non-evaporable getter (NEG) coatings will be used in the SR to support the vacuum. Ion pumps and cold-cathode gauges are typically located away from the vacuum chamber transporting the beam. Measuring gas bremsstrahlung (GB) photons in low-conductance chambers provides a method to determine the pressure at the beam location. We report on GB measurements made in the ID-25 beamline. A Pb:Glass calorimeter radiator generates Cherenkov radiation when high-energy photons cause pair-production within the glass. A photomultiplier tube converts the light pulses to electrical signals. Data was obtained during normal machine operations starting in January 2020. Data collection was facilitated using a 4-channel ITech Beam Loss Monitor FPGA that allows for control of thresholds and attenuation settings in both counting and pulse-height acquisition modes. Count rates and spectra were recorded for the three primary fill patterns typically used during SR operations as well as during gas injection experiments; results of these measurements will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB044
About •	paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021
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MOPAB051	Operation of the ESRF Booster with the New EBS Storage Ring	emittance, booster, SRF, injection	221
	N. Carmignani, L.R. Carver, S.M. Liuzzo, T.P. Perron, S.M. White ESRF, Grenoble, France
	The Extremely Brilliant Source (EBS) has replaced the old ESRF Storage Ring (SR) during the 2019 one-year shutdown. The injector chain, composed of a Linac, a booster synchrotron, and two transfer lines, was not replaced. Nevertheless, some major hardware upgrades were anticipated prior to the long shutdown to ensure its long-term reliability. The shutdown interventions focused on reducing the machine circumference to cope with the new RF frequency of the SR. The status of the upgraded booster will be presented with a focus on the strategy used to lower horizontal emittance especially via emittance exchange.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB051
About •	paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021
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MOPAB077	Anomaly Detection in Accelerator Facilities Using Machine Learning	power-supply, GUI, experiment, detector	304
	A. Das Stanford University, Stanford, California, USA M. Borland, L. Emery, X. Huang, H. Shang, G. Shen ANL, Lemont, Illinois, USA D.F. Ratner SLAC, Menlo Park, California, USA R.M. Smith, G.M. Wang BNL, Upton, New York, USA
	Synchrotron light sources are user facilities and usually run about 5000 hours per year to support many beamlines operations in parallel. Reliability is a key parameter to evaluate machine performance. Even many facilities have achieved >95% beam reliability, there are still many hours of unscheduled downtime and every hour lost is a waste of operation costs along with a big impact on individual scheduled user experiments. Preventive maintenance on subsystems and quick recovery from machine trips are the basic strategies to achieve high reliability, which heavily depends on experts’ dedication. Recently, SLAC, APS, and NSLS-II collaborated to develop machine-learning-based approaches aiming to solve both situations, hardware failure prediction and machine failure diagnosis to find the root sources. In this paper, we report our facility operation status, development progress, and plans.
	Poster MOPAB077 [1.240 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB077
About •	paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 01 September 2021
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MOPAB079	Experience of the First Six Years Operations and Plans in NSlS-II	cavity, MMI, feedback, vacuum	308
	G.M. Wang BNL, Upton, New York, USA
	NSLS-II is a 3 GeV third-generation synchrotron light source at BNL. The storage ring was commissioned in 2014 and began its routine operations in the December of the same year. Since then, we have been continuously installing and commissioning new insertion devices, their front-ends, and beamlines. At this point, the facility hosts 28 operating beamlines from various radiation sources, including damping wiggler, IVU, EPU, 3PW, and bending magnets for infrared beamlines. Over the past six years, the storage ring performance continuously improved, including 500 mA with limited insertion devices close due to RF power limitation and routinely 400 mA top off operation, >95% operation reliability, maintenance of beam motion short- and long-term stability. In this paper, we report NSLS-II accelerator operations experience and plans for future facility developments.
	Poster MOPAB079 [2.064 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB079
About •	paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021
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MOPAB082	Implementation of Using IGBT Switch Based Pulser for TPS Booster Extraction Kicker	extraction, kicker, booster, injection	315
	C.-S. Fann, H.-P. Chang, C.L. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.-K. Lin, K.L. Tsai, C.Y. Wu NSRRC, Hsinchu, Taiwan
	A pair of thyratron-switch-based pulse-forming-network (PFN) pulser has been operating successfully in the past 5 years for TPS booster extraction kickers. In order to improve the flattop of drive-current pulse and to extend possible electron bunch train adjusting knob required, an IGBT-switch-based pulser has been designed, fabricated, and installed onto the TPS booster for its characteristics verification. In this report, the overall technical considerations for the pulser upgrade is described and its beam commissioning results is given for illustration purpose.
	Poster MOPAB082 [0.621 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB082
About •	paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 13 August 2021
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MOPAB091	Injection Section Upgrading with the Septum-Magnet Replacement in KEK-PF Ring	injection, septum, vacuum, storage-ring	342
	C. Mitsuda, K. Harada, N. Higashi, T. Honda, Y. Kobayashi, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, M. Tadano, R. Takai, H. Takaki, Y. Tanimoto, T. Uchiyama, A. Ueda KEK, Ibaraki, Japan
	In 2015, the water leakage happened at the cooling pipe of the in-vacuum septum magnet installed into the injection point. Because the maintenance of the leakage needed the total replacement of the magnet, the water circulation was stopped permanently, and accordingly, the light absorber was installed upstream in the storage ring to prevent the synchrotron light of the bending magnet from coming to the septum wall. This treatment temporally worked well, but the beam injection efficiency was decreased to about 30% due to the physical aperture narrowed by the absorber. With the desired replacement of septum magnet to maintainable out-vacuum type, the injection section upgrading was simultaneously planned to recover and improve the injection efficiency. In this upgrade, the injection beam is closed to the stored beam more than before by adapting the thinner septum structure as a way to improve the injection efficiency. And some new ideas are introduced in the part of monitor and beam duct, for example, realtime beam monitor, thinner Inconel duct. The detailed design of the upgraded injection section and technical points will be reviewed in this conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB091
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 02 September 2021
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MOPAB093	Operational Status of Photon Factory Light Sources	injection, radiation, electron, vacuum	350
	T. Honda, Y. Kobayashi, C. Mitsuda, S. Nagahashi, R. Takai, H. Takaki KEK, Ibaraki, Japan
	One of the recent topics of Photon Factory light sources, PF-ring and PF-AR, is a construction of a GeV-class beamline for testing detectors at the PF-AR. The bremsstrahlung photons generated by a thin carbon wire are brought to a copper target to generate e⁺e⁻ pairs. Sufficient count rates can be expected when the thin wire touching halo of the stored beam, and the test beamline can be used without disturbing the synchrotron radiation experiments. In addition to the usual 6.5-GeV operation, a low-energy operation at 5-GeV was started recently at PF-AR to secure operation time by saving electricity costs. At the PF-ring, the injection section has been upgraded with the septum-magnet replacement. By the top-up injection and improved bunch feedback, the hybrid-fill mode operation has become convenient for both single-bunch users and multi-bunch users, and about 30% or 40% of the user time is scheduled as the hybrid-fill mode now.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB093
About •	paper received ※ 21 May 2021 paper accepted ※ 25 May 2021 issue date ※ 13 August 2021
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MOPAB108	ESRF-EBS 352.37 MHz Radio Frequency System	cavity, SRF, MMI, HOM	395
	J. Jacob, P.B. Borowiec, A. D’Elia, G. Gautier, V. Serrière ESRF, Grenoble, France
	The ESRF 352 MHz Radio Frequency (RF) system has been upgraded and tailored to the new 4th Generation Extremely Brilliant Source EBS, that was installed in 2019 and commissioned in 2020. The five former five-cell cavities were replaced with 13 single cell strongly HOM damped cavities that were developed in house, 10 of which are powered from existing 1 MW klystron transmitters. The remaining three cavities are individually fed by three 150 kW solid state amplifiers. All this required a reconstruction in record time of an elaborate WR2300 waveguide network. The low level RF system as well as the cavity and transmitter control system have been rebuilt. The RF design, commissioning and operation experience will be reported, including plans for a 4th harmonic RF system for bunch lengthening to further improve the performance of the new EBS ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB108
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 02 September 2021
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MOPAB124	APS Booster Injection Horizontal Trajectory Control Upgrade	injection, controls, booster, timing	449
	C. Yao, J.R. Calvey, G.I. Fystro, A.F. Pietryla, H. Shang ANL, Lemont, Illinois, USA
	Funding: * Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO₂-O6CH11357. The APS booster is a 7-GeV electron synchrotron with a 0.5-second cycle. The booster runs a set of injection control programs that correct the beam trajectory in the horizontal and longitudinal planes, and the betatron tunes. Recently we developed a single-turn BPM controllaw program for horizontal trajectory control to replace the previous FFT based horizontal controllaw program. We present the system configuration and results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB124
About •	paper received ※ 15 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021
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MOPAB128	Operational Use of Pinger Magnets to Counter Stored Beam Oscillations During Injection at Diamond Light Source	injection, kicker, diagnostics, storage-ring	459
	R.T. Fielder, M. Apollonio, I.P.S. Martin DLS, Oxfordshire, United Kingdom
	Diamond uses a four kicker bump injection scheme. Due to a variety of factors it has become more difficult to perfectly match the four kicks while maintaining injection efficiency, resulting in some disturbance to the stored beam during top-up. This has consequences for beamlines which may see degraded beam quality during injections. A gating signal is provided, but this is not appropriate for all experiments, and in any case ideally would not be required. The disturbance to the stored beam can be partly controlled using the existing diagnostic pinger magnets installed in the storage ring. We present here a comparison of different compensation schemes and tests with beamlines, along with initial experiences operating during user beam time. Use of these magnet also provides proof of principle for any future, purpose-built compensation kickers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB128
About •	paper received ※ 18 May 2021 paper accepted ※ 20 May 2021 issue date ※ 01 September 2021
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MOPAB140	Gas Sheet Ionization Diagnostic for High Intensity Electron Beams	diagnostics, electron, detector, vacuum	489
	N.P. Norvell, G. Andonian, T.J. Campese, A.-L.M.S. Lamure, M. Ruelas, A.Yu. Smirnov RadiaBeam, Santa Monica, California, USA N.M. Cook RadiaSoft LLC, Boulder, Colorado, USA J.K. Penney UCLA, Los Angeles, California, USA C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by DOE grant DE-SC0019717 The characterization of high intensity charged particle beams in a minimally interceptive, and non-destructive manner is performed using an ionization diagnostic. In this application, a neutral gas is tailored into a thin sheet, or curtain-like, distribution at the interaction point with an electron beam. The electron beam ionizes the neutral gas in localized space, leaving a footprint of the beam transverse distribution. The ion cloud is subseqeuntly imaged with a series of electrostatic lenses to a detector plane. The resultant image is used in a reconstruction algorithm to reconstruct the beam profile at the interaction point. In this paper, we present progress on the development of this diagnostic for the characterization of high charge, 10GeV electron beams with small transverse distributions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB140
About •	paper received ※ 20 May 2021 paper accepted ※ 10 June 2021 issue date ※ 01 September 2021
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MOPAB174	Foil Hits Reduction by Minimizing Injection Beam Size at the Foil in J-PARC RCS	injection, proton, scattering, beam-losses	590
	P.K. Saha, H. Harada, K. Okabe, F. Tamura, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan H. Hotchi KEK, Tokai, Ibaraki, Japan
	Funding: Pranab Kumar Saha The uncontrolled beam loss caused by the foil scattering of the circulating beam during multi-turn charge-exchange injection is one of the main sources for high residual radiation at the injection area of J-PARC 3-GeV rapid cycling synchrotron. We studied to reduce foil hits of the circulating beam by minimizing the vertical injection beam size at the foil and using a smaller vertical foil size. The vertical foil size was reduced according to the injection beam size by maintaining the stripping efficiency. As a result, the number of circulating beam passing through foil was significantly reduced due to smaller foil size. The simulation and measurement results of the foil hits reduction are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB174
About •	paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021
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MOPAB183	A Framework for Dynamic Aperture Studies for Colliding Beams in the High-Luminosity Large Hadron Collider	luminosity, simulation, beam-beam-effects, sextupole	620
	S. Kostoglou, H. Bartosik, Y. Papaphilippou, G. Sterbini CERN, Geneva, Switzerland
	During the last physics run of the Large Hadron Collider (LHC), Dynamic Aperture (DA) studies have been successfully employed to optimize the accelerator’s performance by guiding the selection of the beam and machine parameters. In this paper, we present a framework for single-particle tracking simulations aiming to refine the envisaged operational scenario of the future LHC upgrade, the High-Luminosity LHC (HL-LHC), including strong non-linear fields such as beam-beam interactions. The impact of several parameters and beam processes during the cycle is initially illustrated with frequency maps and then quantified with DA studies.
	Poster MOPAB183 [2.789 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB183
About •	paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 23 August 2021
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MOPAB203	Benchmark of Superconducting Cavity Models at SNS Linac	cavity, linac, superconducting-cavity, simulation	671
	A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. A benchmark of superconducting cavity models against Time-of-Flight measurements at the SNS linac is presented. The superconducting part of SNS linac (SCL) includes 81 RF cavities that accelerates H⁻ beam from 185.6 MeV to the final energy of 1 GeV. During the operation some of cavities can become unstable, and its amplitudes should be reduced, or they should be completely switched off. In this case, the SCL is retuned by using a linac simulation code. This simulation tool relay on an accuracy of the superconducting cavity model. This paper describes the comparison of the measured beam acceleration by one of the SCL cavities and simulations of this process. Different cavity models are used in simulations. The subject of this study is limited to the longitudinal beam dynamics, so no effects on transverse beam characteristics have been considered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB203
About •	paper received ※ 14 May 2021 paper accepted ※ 20 May 2021 issue date ※ 24 August 2021
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MOPAB208	LLRF Measurements and Cu-plating at the First-of-Series Cavity Section of the Alvarez 2.0 at GSI	cavity, DTL, simulation, vacuum	686
	M. Heilmann, T. Dettinger, X. Du, L. Groening, S. Mickat, A. Rubin GSI, Darmstadt, Germany
	The Alvarez 2.0 will replace the existing post-stripper DTL of the GSI UNILAC. Today’s GSI comprises the UNILAC and the synchrotron SIS18 and is going to serve as the injector chain for the Facility of Antiproton and Ion Research (FAIR). The new Alvarez-type DTL is operated at 10⁸.4 MHz providing acceleration from 1.4 MeV/u to 11.4 MeV/u along a total length of 55 meters. The first-of-series (FoS) cavity section has 12 RF-gaps along a total length of 1.9 m. It is the first cavity section of the new DTL. All main components were delivered in 2019, followed by successful SAT and installation of the 11 drift tubes and copper-plating. Completion of first low level RF-measurements prior to copper plating and the subsequent plating are major project milestones. These proceedings report on the results and compares them to simulation using CST Microwave Studio.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB208
About •	paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 22 August 2021
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MOPAB217	A Storage Ring for MESA	target, experiment, optics, simulation	719
	C.P. Stoll, A. Meseck KPH, Mainz, Germany B. Ledroit HIM, Mainz, Germany
	The Mainz Energy-recovering Superconducting Accelerator (MESA) is an Energy Recovery Linac (ERL) facility under construction at the Johannes Gutenberg-University in Mainz. It provides the opportunity for precision physics experiments with a 1 mA c.w. electron beam in its initial phase. In this phase experiments with unpolarised, high density 10¹⁹ atoms cm² gas jet targets are foreseen at the Mainz Gas Internal Target Experiment (MAGIX). To allow experiments with thin polarised gas targets with sufficiently high interaction rates in a later phase, the beam current has to be increased to up to 100 mA, which would pose significant challenges to the existing ERL machine. Thus, it is proposed here to use MESA in pulsed operation with a repetition rate of several kHz to fill a storage ring, providing a quasi c.w. beam current to a thin gas target. For this purpose, the existing optics need to be extended and adapted, a suitable injection and extraction scheme is necessary and beam target interaction must be investigated. First considerations on these topics are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB217
About •	paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 21 August 2021
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MOPAB228	Introducing two Energy-Correction Schemes at DELTA	storage-ring, simulation, closed-orbit, injection	740
	S. Kötter DELTA, Dortmund, Germany
	At DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University, two methods to correct the beam energy of the storage ring have been tested. The first one is capable of maintaining the current beam energy. The second method is used to find the optimal orbit length. Here, the ideas behind both methods are explained and first test results are presented. Numerical studies are shown together with measurement results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB228
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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MOPAB229	Compensations of Third-Order Resonances in J-PARC MR	resonance, sextupole, optics, survey	744
	T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa KEK, Tokai, Ibaraki, Japan
	The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 10¹³ protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (ν_x, ν_y) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is ν_x-2ν_y=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3ν_x=64 and ν_x+2ν_y=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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MOPAB253	Comparison of Transfer Map Derivation Methods for Static Magnetic Fields	multipole, quadrupole, lattice, extraction	799
	J.A. Crittenden, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811. We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253
About •	paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 13 August 2021
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MOPAB270	Beam Dynamics Studies in a Standing Wave Ka-band Linearizer	electron, emittance, bunching, simulation	857
	J. Scifo, M. Behtouei, L. Faillace, M. Ferrario, A. Giribono, B. Spataro, C. Vaccarezza INFN/LNF, Frascati, Italy M. Migliorati INFN-Roma1, Rome, Italy M. Migliorati Sapienza University of Rome, Rome, Italy G. Torrisi INFN/LNS, Catania, Italy
	Next-generation FEL user facilities require high-quality electron beams with kA peak current. The combination of a high brightness RF injector and a magnetic compression stage represents a very performant solution in terms of electron beam emittance and peak current. One of the important issues is the design of a proper device that acts as a linearizer for the beam longitudinal phase space. Recently, the design of a SW Ka band RF accelerating structure has been proposed with promising results. The paper reports on electron beam dynamics studies in the described RF structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB270
About •	paper received ※ 19 May 2021 paper accepted ※ 29 August 2021 issue date ※ 26 August 2021
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MOPAB272	Consideration the Prospects of Beam Diagnostic System Upgrade in the Transport Channels of Injection Complex VEPP-5	positron, electron, injection, diagnostics	860
	K.V. Astrelina, F.A. Emanov BINP SB RAS, Novosibirsk, Russia F.A. Emanov NSU, Novosibirsk, Russia
	Transport electron and positron channels from linear accelerator to storage ring of Injection Complex VEPP-5 (BINP, Novosibirsk) have complicated 3D configuration and equipped only with luminophore screens as a beam test. For the regular machine operations the non-destructive beam diagnostic system is required to adjust the electron and positron beam trajectories and minimize the beam losses. The proposal of new beam position monitors (BPM) assembling is considered. Newly added BPMs allow one to control the beam trajectory during operations. Collecting beam position data in several points makes it possible to calculate and correct the beamline parameters: Twiss parameters, dispersion, beam energy variations. The possible configuration of the new BPMs placing is suggested and the rate of beam loss reducing due the additional diagnostics is estimated.
	Poster MOPAB272 [1.164 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB272
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 02 September 2021
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MOPAB288	Real-Time Edge AI for Distributed Systems (READS): Progress on Beam Loss De-Blending for the Fermilab Main Injector and Recycler	network, real-time, distributed, FPGA	912
	K.J. Hazelwood, M.R. Austin, M.A. Ibrahim, V.P. Nagaslaev, A. Narayanan, D.J. Nicklaus, A.L. Saewert, B.A. Schupbach, K. Seiya, R.M. Thurman-Keup, N.V. Tran Fermilab, Batavia, Illinois, USA H. Liu, S. Memik, R. Shi, M. Thieme Northwestern University, Evanston, Illinois, USA A. Narayanan Northern Illinois University, DeKalb, Illinois, USA
	The Fermilab Main Injector enclosure houses two accelerators, the Main Injector and Recycler. During normal operation, high intensity proton beams exist simultaneously in both. The two accelerators share the same beam loss monitors (BLM) and monitoring system. Beam losses in the Main Injector enclosure are monitored for tuning the accelerators and machine protection. Losses are currently attributed to a specific machine based on timing. However, this method alone is insufficient and often inaccurate, resulting in more difficult machine tuning and unnecessary machine downtime. Machine experts can often distinguish the correct source of beam loss. This suggests a machine learning (ML) model may be producible to help de-blend losses between machines. Work is underway as part of the Fermilab Real-time Edge AI for Distributed Systems Project (READS) to develop a ML empowered system that collects streamed BLM data and additional machine readings to infer in real-time, which machine generated beam loss.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB288
About •	paper received ※ 19 May 2021 paper accepted ※ 29 July 2021 issue date ※ 13 August 2021
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MOPAB296	Statistical Analysis of 2D Single-Shot PPRE Bunch Measurements	photon, radiation, diagnostics, storage-ring	939
	M. Koopmans, J.-G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz HZB, Berlin, Germany
	The pulse picking by resonant excitation (PPRE) method* is used to realize pseudo single-bunch radiation from a complex filling pattern at the BESSY II storage ring. The PPRE bunch is excited in the horizontal plane by a quasi-resonant incoherent perturbation to increase the emittance of this bunch. Therefore, the synchrotron light of the PPRE bunch can be separated by collimation from the radiation of the main bunch train at dedicated beamlines for timing users. The properties of the PPRE bunch depend on the storage ring settings and on the excitation parameters. It is not trivial to distinguish between the wanted intrinsic bunch broadening and an additional position fluctuation of the PPRE bunch. Using the potential of the new diagnostics beamline with the possibility to observe an additional spatial dimension with a fast streak camera, we introduce a new method to study the properties of the PPRE bunch. Applying a statistical analysis to a series of single-turn images enables distinguishing between horizontal orbit motion and the broadening of the bunch due to the excitation. Measurements are presented and the results are compared with data from the BPM system. K. Holldack et al., Nature Commun. 5 (2014) 4010. J.-G. Hwang et al., Nucl. Instrum. Methods A940 (2019) 387. * G. Schiwietz et al., Nucl. Instrum. Methods A990 (2021) 164992.
	Poster MOPAB296 [2.074 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB296
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 23 August 2021
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MOPAB313	Argonaut - A Robotic System for Cryogenic Environments	detector, diagnostics, cryogenics, electron	966
	W. Pellico, N.M. Curfman, M. Wong-Squires Fermilab, Batavia, Illinois, USA
	Funding: Department of Energy Fermilab and the HEP community invest significant resources into liquid argon detectors. The largest and most expensive of these detectors will be located in the Deep Underground Neutrino Experiment (DUNE). However, recent experiences have shown that there are limited avenues of monitoring, intervention, and interaction in the internal liquid environment. This proposal shows a technological path that could provide a valuable tool to ensure or at least improve the management of these HEP detectors. The development of a robotic system named Argonaut will demonstrate several technologies including 1) demonstration of suitable mobility of a small robotic device at liquid argon temperatures, 2) demonstration of wireless communication, 3) demonstration of improved diagnostics capabilities - such as tunable optics with motion control, 4) demonstration of interconnectivity of a robotic system with hardware residing within the detector. This initial research will be a seed for extended development in cold robotics and associated technologies. This work will allow FNAL to contribute a significant technology capability to recent efforts to cryogenic detector operations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB313
About •	paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 25 August 2021
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MOPAB314	Surrogate Modeling for MUED with Neural Networks	electron, experiment, gun, network	970
	D.J. Monk, S. Biedron, M.A. Fazio, M. Martínez-Ramón, S.I. Sosa Guitron UNM-ECE, Albuquerque, USA M. Babzien, K.A. Brown, M.A. Palmer, J. Tao BNL, Upton, New York, USA D. Martin, M.E. Papka ANL, Lemont, Illinois, USA T. Talbott UNM-ME, Albuquerque, New Mexico, USA
	Electron diffraction is among the most complex and influential inventions of the last century and contributes to research in many areas of physics and engineering. Not only does it aid in problems like materials and plasma research, electron diffraction systems like the MeV ultra-fast electron diffraction(MUED) instrument at the Brookhaven National Lab(BNL) also present opportunities to explore/implement surrogate modeling methods using artificial intelligence/machine learning/deep learning algorithms. Running the MUED system requires extended periods of uninterrupted runtime, skilled operators, and many varying parameters that depend on the desired output. These problems lend themselves to techniques based on neural networks(NNs), which are suited to modeling, system controls, and analysis of time-varying/multi-parameter systems. NNs can be deployed in model-based control areas and can be used simulate control designs, planned experiments, and to simulate employment of new components. Surrogate models based on NNs provide fast and accurate results, ideal for real-time control systems during continuous operation and may be used to identify irregular beam behavior as they develop.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB314
About •	paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 15 August 2021
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MOPAB320	The CMS ECAL Enfourneur: A Gigantic Machine with a Soft Touch	controls, alignment, insertion, experiment	986
	V. Pettinacci INFN-Roma, Roma, Italy
	The electromagnetic calorimeter (ECAL) of the CMS experiment at the LHC is composed of 75848 scintillating lead tungstate crystals arranged in a barrel section and two endcaps. The barrel part is made of 36 supermodules (SM), 2.7 tons each, and is installed inside the CMS magnet. There are 18 SMs on each side of CMS, with each SM containing 1700 crystals. During Long Shutdown 3, all ECAL SMs must be extracted to refurbish the electronics in preparation for HL-LHC. A dedicated machine called the "Enfourneur" is used to extract and re-insert the SMs inside CMS, with a required accuracy of about 1mm. In order to speed up the extraction and insertion process, two Enfourneurs will be employed, operating in parallel on both sides. In view of the purchase of the second Enfourneur, the design has been improved, starting from the feedback of past operations. The improvements to the new Enfourneur design include increased space for the operators, optimization of the operations and the controls with the use of electric motors, and an updated alignment system. Handling plans inside the CMS cavern have been defined in order to be compliant with the rest of CMS structures and procedures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB320
About •	paper received ※ 11 May 2021 paper accepted ※ 17 August 2021 issue date ※ 20 August 2021
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MOPAB334	Status and Recent Development of FAIR Ring RF Systems	cavity, LLRF, power-supply, status	1037
	U. Laier, R. Balß, C. Christoph, M. Frey, P. Hülsmann, H. Klingbeil, H.G. König, D.E.M. Lens, J.S. Schmidt, A. Stuhl, K.G. Thomin, T. Winnefeld GSI, Darmstadt, Germany H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: GSI Helmholtzzentrum für Schwerionenforschung GmbH Five different Ring RF Systems are required for the operation of FAIR (Facility for Antiproton and Ion Research). These systems have to operate at frequencies between 310 kHz and 3.2 MHz, with gap voltages up to 40 kVp and duty cycles from 5·10^-4 up to cw. All systems will be realized using inductively loaded (ferrite or magnetic alloy) cavities driven by tetrode-based amplifiers fed by switch-mode power supplies. To stabilize the amplitude, resonance frequency and phase, versatile digital feedback and feedforward control will be used. This contribution will present the latest development on the power part and the LLRF of the four RF systems of the SIS100 (SIS100 Acceleration, SIS100 Bunch Compression, SIS100 Barrier Bucket and SIS100 Longitudinal Feedback) as well as the CR Debuncher system which is part of the Collector Ring. The progress of these systems varies by a large degree. This note will give an overview regarding the status of the design, procurement, realization, testing, optimization, commissioning and preparation for installation of these RF systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB334
About •	paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021
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MOPAB335	SNS Warm Linac Circulator Breakdown Considerations for the PPU Project	linac, simulation, DTL, proton	1041
	G.D. Toby, Y.W. Kang, S.-H. Kim, S.W. Lee, J.S. Moss ORNL, Oak Ridge, Tennessee, USA
	Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725. Multipacting in accelerating structures is a complex phenomenon about which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures which have a higher thermal capacity, and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Benchmarking of the peak electric fields in these structures, benefits of material processing and possible techniques for reducing or eliminating multipacting activities are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB335
About •	paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 23 August 2021
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MOPAB340	Experimental Tests with the First Segment of ESS-Bilbao RFQ Linac	rfq, vacuum, simulation, experiment	1054
	J.L. Muñoz, I. Bustinduy, A. Conde, N. Garmendia, P.J. González, J. Martin, A. Zugazaga ESS Bilbao, Zamudio, Spain
	The ESS-Bilbao RFQ is an assembly of four segments, each one about 800 mm in length. The first segment has been manufactured before the others, so it could be thoroughly tested in order to validate the chosen technological approach for the RFQ, as it uses polymeric vacuum gaskets and bolts instead of brazing. In this paper we report on the tests run with the segment and their results. Vacuum tests, metrology measurements, low power RF tests as well as extensive tuning tests measuring the cavity resonant quadrupolar frequency as a function of cooling water temperature have been done. Experimental results are compared to the expected values obtained from numerical simulations. We describe the experimental set-ups for the measurements and the simulations. Results are analyzed with the aim of validating the design, and also to provide predictions for tuning and operation of the whole RFQ. As a consequence of the positive results of the tests reported here, the remaining segments have already been tendered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB340
About •	paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 20 August 2021
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MOPAB341	First C-Band High Gradient Cavity Testing Results at LANL	cavity, proton, GUI, klystron	1057
	E.I. Simakov, R.L. Fleming, D. Gorelov, T.A. Jankowski, M.F. Kirshner, J.W. Lewellen, J.D. Pizzolatto, M.E. Schneider, T. Tajima LANL, Los Alamos, New Mexico, USA X. Lu, E.A. Nanni, S.G. Tantawi SLAC, Menlo Park, California, USA M.E. Middendorf ANL, Lemont, Illinois, USA
	Funding: Los Alamos National Laboratory LDRD Program. This poster will report the results of high gradient testing of the two proton β=0.5 C-band accelerating cavities. The cavities for proton acceleration were fabricated at SLAC and tested at high gradient C-band accelerator test stand at LANL. One cavity was made of copper, and the second was made of a copper-silver alloy. LANL test stand was constructed around a 50 MW, 5.712 GHz Canon klystron and is capable to provide power for conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. These β=0.5 C-band cavities were the first two cavities tested on LANL C-band test stand. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB341
About •	paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 30 August 2021
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MOPAB344	Machine Learning Models for Breakdown Prediction in RF Cavities for Accelerators	cavity, network, vacuum, linac	1068
	C. Obermair, A. Apollonio, T. Cartier-Michaud, N. Catalán Lasheras, L. Felsberger, W.L. Millar, W. Wuensch CERN, Geneva, Switzerland C. Obermair, F. Pernkopf TUG, Graz, Austria
	Radio Frequency (RF) breakdowns are one of the most prevalent limits in RF cavities for particle accelerators. During a breakdown, field enhancement associated with small deformations on the cavity surface results in electrical arcs. Such arcs degrade a passing beam and if they occur frequently, they can cause irreparable damage to the RF cavity surface. In this paper, we propose a machine learning approach to predict the occurrence of breakdowns in CERN’s Compact LInear Collider (CLIC) accelerating structures. We discuss state-of-the-art algorithms for data exploration with unsupervised machine learning, breakdown prediction with supervised machine learning, and result validation with Explainable-Artificial Intelligence (Explainable AI). By interpreting the model parameters of various approaches, we go further in addressing opportunities to elucidate the physics of a breakdown and improve accelerator reliability and operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB344
About •	paper received ※ 20 May 2021 paper accepted ※ 16 July 2021 issue date ※ 11 August 2021
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MOPAB345	Machine Learning with a Hybrid Model for Monitoring of the Protection Systems of the LHC	monitoring, superconducting-magnet, dipole, machine-protect	1072
	C. Obermair, A. Apollonio, Z. Charifoulline, M. Maciejewski, A.P. Verweij CERN, Geneva, Switzerland C. Obermair, F. Pernkopf TUG, Graz, Austria
	The LHC is the world’s largest particle accelerator and uses a complex set of sophisticated and highly reliable machine protection systems to ensure a safe operation with high availability for particle physics production. The data gathered during several years of successful operation allow the use of data-driven methods to assist experts in finding anomalies in the behavior of those protection systems. In this paper, we derive a model that can extend the existing signal monitoring applications for the LHC protection systems with machine learning. Our hybrid model combines an existing threshold-based system with a SVM by using signals, manually validated by experts. Even with a limited amount of data, the SVM learns to integrate the expert knowledge and contributes to a better classification of safety-critical signals. Using this approach, we analyze historical signals of quench heaters, which are an important part of the quench protection system for superconducting magnets. Particularly, it is possible to incorporate expert decisions into the classification process and to improve the failure detection rate of the existing quench heater discharge analysis tool.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB345
About •	paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 01 September 2021
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MOPAB359	Operational Experience and Redesign of the Tuner without Spring Fingers for the LEReC Warm Cavity	cavity, vacuum, SRF, electron	1116
	B.P. Xiao, J.M. Brennan, J.C. Brutus, K. Mernick, S. Polizzo, S.K. Seberg, F. Severino, K.S. Smith, A. Zaltsman BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A folded coaxial tuner without spring fingers was designed for the Low Energy RHIC electron Cooler (LEReC) 2.1 GHz warm cavity. During RHIC run 2019, this tuner was found to cause cavity trips via different failure modes. After analyzing these failure modes, a new straight coaxial tuner without spring fingers was proposed and was installed. We show the operational experience of the new tuner in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB359
About •	paper received ※ 17 May 2021 paper accepted ※ 25 June 2021 issue date ※ 29 August 2021
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MOPAB363	Design, Characteristics and Dynamic Properties of Mobile Plunger-based Frequency Tuning System for Coaxial Half Wave Resonators	cavity, experiment, controls, resonance	1129
	D. Bychanok, S. Huseu, S.A. Maksimenko, A.E. Sukhotski INP BSU, Minsk, Belarus A.V. Butenko, E. Syresin JINR, Dubna, Moscow Region, Russia M. Gusarova, M.V. Lalayan, S.M. Polozov MEPhI, Moscow, Russia V.S. Petrakovsky, A.I. Pokrovsky, A. Shvedov, S.V. Yurevich Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus Y. Tamashevich HZB, Berlin, Germany
	The practical realization of a prototype of the frequency tuning system (FTS) for coaxial half-wave cavities (HWR) for the Nuclotron-based Ion Collider fAcility (NICA) injector is presented. The impact of FTS on electromagnetic parameters of copper HWR prototype is experimentally studied and discussed. The most important parameters like tuning range, tuning sensitivity, the dependence of the resonant frequency on the position of the plungers are estimated. The effective operation algorithms of the proposed FTS are discussed and analyzed. The dynamic characteristics of FTS are investigated and showed the ability to adjust the frequency with an accuracy of about 70 Hz.
	Poster MOPAB363 [3.597 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB363
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021
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MOPAB392	Alternative RF Tuning Methods Performed on Spoke Cavities for ESS and MYRRHA Projects	cavity, target, simulation, experiment	1196
	P. Duchesne, S. Blivet, G. Olivier, G. Olry, T. Pépin-Donat Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	In order to obtain the target frequency in operation, the resonant frequency of superconducting radiofrequency cavities is controlled and adjusted from the manufacturing to the end of preparation phase. Reaching this right frequency can be challenging due to the narrow frequency range defined by the tuning sensitivity of the cavity and the capability of the tuner. Mechanical deformation until plasticity is attained is of great interest to tune SRF cavities when large frequency shift is needed. But once a cavity is dressed with its helium tank, the only accessible part is its beam pipe, reducing the mechanical action to a push/pull action. This limited possibility has hence to be skilfully associated with chemical etching. An original mechanical tuning of Spoke dressed cavities consists in increasing the pressure inside the helium tank to induce a permanent deformation of the cavity walls. The frequency shift induced by nonlinear deformation is numerically evaluated in order to determine the pressure increments. Both methods were successfully performed on the cavities of the ESS accelerator and of the Myrrha project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB392
About •	paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 17 August 2021
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MOPAB410	Preliminary Studies of a Compact VHEE Linear Accelerator System for FLASH Radiotherapy	linac, radiation, electron, impedance	1229
	L. Giuliano, F. Bosco, M. Carillo, D. De Arcangelis, L. Faillace, L. Ficcadenti, M. Migliorati, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy D. Alesini, M. Behtouei, B. Spataro INFN/LNF, Frascati, Italy G. Cuttone, G. Torrisi INFN/LNS, Catania, Italy V. Favaudon, S. Heinrich, A. Patriarca Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France
	Funding: The work is supported by La Sapienza University, research grant "grandi progetti di ricerca 2020". The Flash Radio Therapy is a revolutionary new technique in the cancer cure: it spares healthy tissue from the damage of the ionizing radiation maintaining the tumor control as efficient as in conventional radiotherapy. To allow the implementation of the FLASH Therapy concept into actual clinical use, it is necessary to have a linear accelerator able to deliver the very high dose and very high dose rate (>10⁶ Gy/s) in a very short irradiation time (beam on time < 100ms). Low energy S-band Linacs (up to 7 MeV) are being used in Radiobiology and pre-clinic applications but in order to treat deep tumors, the energy of the electrons should achieve the range of 60-100 MeV. In this paper, we address the main issues in the design of a compact C band (5.712 GHz) electron linac-VHEE for FLASH Radio Therapy. We present preliminary studies on C-band structures at La Sapienza and at INFN-LNS, aiming to reach a high accelerating gradient and high current necessary to deliver a dose >1 Gy/pulse, with very short electron pulse.
	Poster MOPAB410 [0.650 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB410
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021
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MOPAB412	Accelerator Production of Mo-99 Using Mo-100	target, radiation, electron, diagnostics	1237
	J.L. McCarter, M.J. Brennan, S.M. Burns, J.T. Harvey, S.W. Kelley, T.A. Montenegro, Q. Schiller NorthStar Medical Technologies, LLC, Beloit, USA
	Funding: DE-NA0001878 Tc-99m is an essential radionuclide for nearly 40,000 diagnostic nuclear medicine tests in the U.S. each day. Its daily production depends on Mo-99, which must be replenished weekly due to Mo-99’s 2.75 day half-life. Mo-99, in the past, was supplied from uranium fission production, depending on overseas nuclear reactors that average 50 years old. Their age in combination with shipment uncertainties make the availability of Mo-99 fragile and subject to severe shortages. The U.S. now has one domestic, FDA-approved supplier that produces Mo-99, NorthStar Medical Radioisotopes. Currently, NorthStar produces Mo-99 via the irradiation of Mo-98 in a nuclear reactor. In the future, NorthStar will also irradiate Mo-100 with accelerator created x-rays to produce Mo-99. This process will use 2 distinct, 40 MeV, 125 kW average electron accelerators, Rhodotrons produced by IBA. Accelerator produced Mo-99 has several advantages over that produced by reactors, including a dual supply and an ability to adjust irradiation timing to meet radiopharmacy demands, such as Sunday delivery. NorthStar is currently installing and commissioning this accelerator based system, entering production in late-2022.
	Poster MOPAB412 [2.150 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB412
About •	paper received ※ 24 May 2021 paper accepted ※ 07 June 2021 issue date ※ 19 August 2021
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MOPAB413	The Next Ion Medical Machine Study at CERN: Towards a Next Generation Cancer Research and Therapy Facility with Ion Beams	synchrotron, linac, proton, superconducting-magnet	1240
	M. Vretenar, V. Bencini, E. Benedetto, M.R. Khalvati, A.M. Lombardi, M. Sapinski, D. Tommasini CERN, Meyrin, Switzerland E. Benedetto, M. Sapinski TERA, Novara, Italy P. Foka GSI, Darmstadt, Germany
	Cancer therapy with ions has several advantages over X-ray and proton therapy, but its diffusion remains limited primarily because of the size and cost of the accelerator. To develop technologies that might improve performance and reduce accelerator cost with respect to present facilities, CERN has recently launched the Next Ion Medical Machine Study (NIMMS), leveraging CERN expertise in accelerator fields to disseminate technologies developed for basic science. A perspective user and key partner of NIMMS is the SEEIIST (South East European International Institute for Sustainable Technologies), established to build in the region an innovative facility for combined cancer therapy and biomedical research with ion beams. For SEEIIST and other potential users, three options are being considered. Conceptual designs of a warm-magnet synchrotron at high beam intensity, of a compact superconducting synchrotron, and of a high-frequency linear accelerator have been compared in terms of cost, risk and development time. The development of curved superconducting magnets, of compact synchrotrons and ion gantries, and of linacs is being pursued within EU-funded projects or specific collaborations
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB413
About •	paper received ※ 18 May 2021 paper accepted ※ 20 July 2021 issue date ※ 13 August 2021
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TUXA03	Progress in Mastering Electron Clouds at the Large Hadron Collider	simulation, electron, luminosity, experiment	1273
	G. Iadarola, B. Bradu, L. Mether, K. Paraschou, V. Petit, G. Rumolo, L. Sabato, G. Skripka, M. Taborelli, L.J. Tavian CERN, Geneva, Switzerland K. Paraschou AUTH, Thessaloniki, Greece
	During the second operational run of the Large Hadron Collider (LHC) a bunch spacing of 25 ns was used for the first time for luminosity production. With such a spacing, electron cloud effects are much more severe than with the 50-ns spacing, which had been used in the previous run. Beam-induced conditioning of the beam chambers mitigated the e-cloud formation to an extent that allowed an effective exploitation of 25 ns beams. Nevertheless, even after years of conditioning, e-cloud effects remained very visible, affecting beam stability and beam quality, and generating strong heat loads on the beam screens of the superconducting magnets with puzzling features. In preparation for the High Luminosity LHC upgrade, remarkable progress has been made in the modeling of the e-cloud formation and of its influence on beam stability, slow losses and emittance blow up, as well as in the understanding of the underlying behavior of the beam-chamber surface. In this contribution, we describe the main experimental observations from beam operation, the outcome of laboratory analysis conducted on beam screens extracted after the run, and the main advancements in the modeling of these phenomena.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA03
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 29 August 2021
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TUXA04	Coherent Excitations and Circular Attractors in Cooled Ion Bunches	electron, collider, experiment, proton	1279
	S. Seletskiy, A.V. Fedotov, D. Kayran BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy In electron coolers, under certain conditions, a mismatch in either gamma-factors or trajectory angles between an electron and an ion beam can cause the formation of a circular attractor in the ion beam phase space. This leads to coherent excitations of the ions with a small synchrotron or betatron amplitude and results in unusual beam dynamics, including bifurcations. In this paper, we consider the effect of coherent excitations and discuss its implications both for Low Energy RHIC Electron Cooler (LEReC) and for high energy electron coolers proposed for the Electron-Ion Collider (EIC).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA04
About •	paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 11 August 2021
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TUXC03	Ferro-Electric Fast Reactive Tuner Applications for SRF Cavities	cavity, SRF, beam-loading, controls	1305
	N.C. Shipman, A. Castilla, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley, H. Timko CERN, Geneva, Switzerland I. Ben-Zvi BNL, Upton, New York, USA G. Burt, A. Castilla Cockcroft Institute, Lancaster University, Lancaster, United Kingdom C.-J. Jing, A. Kanareykin Euclid TechLabs, Solon, Ohio, USA
	A Ferro-Electric fast Reactive Tuner (FE-FRT) is a novel type of RF cavity tuner containing a low loss ferroelectric material. FE-FRTs have no moving parts and allow cavity frequencies to be changed extremely quickly (on the timescale of 100s of ns or less). They are of particular interest for SRF cavities as they can be placed outside the liquid helium environment and without an FE-FRT it’s typically very difficult to tune SRF cavities quickly. FE-FRTs can be used for a wide variety of use cases including microphonics suppression, RF switching, and transient beam loading compensation. This promises entirely new operational capabilities, increased performance and cost savings for a variety of existing and proposed accelerators. An overview of the theory and potential applications will be discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC03
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 25 August 2021
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TUPAB060	Machine Learning on Beam Lifetime and Top-Up Efficiency	network, storage-ring, emittance, photon	1499
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Both unsupervised and supervised machine learning techniques are employed for automatic clustering, modeling and prediction of Advanced Photon Source (APS) storage ring beam lifetime and top-up efficiency archived in operations. The naive Bayes classifier algorithm is developed and combined with k-means clustering to improve accuracy, where the unsupervised clustering of APS beam lifetime and top-up efficiency is consistent with either true label from data archive or Gaussian kernel density estimation. Artificial neural network algorithms have been developed, and employed for training and modelling the arbitrary relations of beam lifetime and top-up efficiency on many observable parameters. The predictions from artificial neural network reasonably agree with the APS operation data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB060
About •	paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021
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TUPAB061	Anomaly Detection by Principal Component Analysis and Autoencoder Approach	network, power-supply, storage-ring, photon	1502
	Y.P. Sun ANL, Lemont, Illinois, USA
	Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Several different approach are employed to identify the abnormal events in some Advanced Photon Source (APS) operation archived dataset, where dimensionality reduction are performed by either principal component analysis or autoencoder artificial neural network. It is observed that the APS stored beam dump event, which is triggered by magnet power supply fault, may be predicted by analyzing the magnets capacitor temperatures dataset. There is reasonable agreement among two principal component analysis based approaches and the autoencoder artificial neural network approach, on predicting future overall system fault which may result in a stored beam dump in the APS storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB061
About •	paper received ※ 22 May 2021 paper accepted ※ 18 June 2021 issue date ※ 19 August 2021
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TUPAB063	Study of PF-Ring Infrastructure Improvements Using Temperature Measurements in the Ring Tunnel	injection, controls, experiment, radiation	1508
	N. Nakamura, K. Haga, T. Nogami, M. Tadano KEK, Ibaraki, Japan
	Temperature measurements have been performed in the PF-ring tunnel in order to understand the infrastructure performance and the temperature stability towards the PF upgrade project, where better beam stability will be required. Based on the temperature measurements, possible improvements of the PF-ring infrastructure such as an air-conditioning system have been studied to enhance the temperature stability in the PF-ring tunnel. In this paper, we present results of the temperature measurements in the PF-ring tunnel and a proposal of the PF-ring infrastructure improvements for the temperature stabilization.
	Poster TUPAB063 [6.169 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB063
About •	paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB064	Specifications and Performance of a Chicane Magnet for the cERL IR-FEL	FEL, undulator, dipole, operational-performance	1512
	N. Nakamura, K. Harada, N. Higashi, Y. Honda, R. Kato, C. Mitsuda, S. Nagahashi, T. Obina, H. Sakai, M. Shimada, H. Takaki, O.A. Tanaka KEK, Ibaraki, Japan Y. Lu Sokendai, Ibaraki, Japan
	Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)". The IR-FEL was constructed in the Compact ERL (cERL) at KEK from October 2019 to May 2020 for the purpose of developing high-power mid-infrared lasers for high-efficiency laser processing utilizing molecular vibrational absorption. The chicane magnet was newly installed between two IR-FEL undulators in the cERL in order to increase the FEL gain and pulse energy by converting the energy modulation to the density modulation in an electron bunch. It consists of three dipole magnets with laminated yokes made of 0.1-mm-thick permalloy sheets and the coil currents of the three magnets are independently controlled by three power supplies with the maximum current of 10 A. The maximum closed orbit bump made by the chicane magnetic field has the longitudinal dispersion(R56) of -6 mm. The coil-current ratio of the three dipole magnets was tuned after installation to make its orbit bumps closed and then the chicane magnet was used in the FEL operation. We present specifications and operational performance of the chicane magnet.
	Poster TUPAB064 [4.053 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB064
About •	paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 25 August 2021
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TUPAB065	Solaris Storage Ring Performance After 6 Years of Operation	storage-ring, MMI, synchrotron, vacuum	1515
	A.I. Wawrzyniak, A. Curcio, K. Gula, M.A. Knafel, G.W. Kowalski, A.M. Marendziak, R. Panaś, M. Waniczek, M. Wiśniowski NSRC SOLARIS, Kraków, Poland
	Solaris is a third generation light source operating since 2015 in Kraków, Poland. Between 2015 and 2018 the synchrotron as well as two beamlines were commissioned. During commissioning phases, the good performance of Solaris storage ring has been reached. The beam optics was brought close to the design one. Since October 2018 Solaris storage ring is in the user operation mode. Moreover, two other beamlines with the elliptically polarized undulators used as source were installed and are under commissioning now. In 2020 the total beam availability of 93% was reached with the average circulating current of 400 mA and the total lifetime of 15 h. Over last two years few improvements of the storage ring were done to optimize the storage ring performance. The Landau cavities were tuned to improve the Touschek lifetime and suppress the instabilities. Two diagnostics beamlines were installed and commissioned allowing for the beam sizes in three planes and emittance measurements. The storage ring optics was fine-tuned to increase the dynamic aperture.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB065
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB067	Production of 120 MeV Gamma-ray Beams at Duke FEL and HIGS Facility	FEL, wiggler, radiation, diagnostics	1522
	S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, Y.K. Wu, J. Yan FEL/Duke University, Durham, North Carolina, USA M.W. Ahmed, M. Sikora TUNL, Durham, North Carolina, USA H. Ehlers, L.O. Jensen, L. Kochanneck Laser Zentrum Hannover, Hannover, Germany
	Funding: This work is supported by the US DoE grant #DE-FG02-97ER41033 In this paper we report extension of the operational energy of the gamma ray beams produced at Duke High Intensity Gamma-ray Source (HIGS) up to ~120MeV, opening up a new high energy region of gamma rays for photonuclear physics research. This achievement is based upon development of radiation robust, thermally stable, high-reflectivity fluoride (LaF3/MgF2) multilayer VUV FEL mirrors, enabling us to maintain stable high intensity FEL lasing at the wavelengths of around 175nm. We discuss the challenges of HIGS operation at high gamma and high electron beam energies with the downstream FEL mirror exposed to extremely hush radiation. The experience of the first HIGS user operation with high intensity, high gamma-ray beam energies (85 and ~120MeV) using these new mirrors is also discussed.
	Poster TUPAB067 [1.023 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB067
About •	paper received ※ 30 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021
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TUPAB074	S-Band Transverse Deflecting Structure Design for CompactLight	klystron, FEL, cavity, impedance	1540
	X.W. Wu, W. Wuensch CERN, Meyrin, Switzerland S. Di Mitri Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy N. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, which is based on high-gradient X-band (12 GHz) structures. However, to carry out pump-and-probe experiments in the project, two-bunch operation with a spacing of 10 X-band rf cycles is proposed. A sub-harmonic transverse deflecting structure working at S-band is proposed to direct the two bunches into two separate FEL lines. The two FEL pulses will have independently tunable wavelengths and can be combined in a single experiment with a temporal delay between pulses of ± 100 fs. The rf design of the transverse deflector is presented in this paper.
	Poster TUPAB074 [1.557 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB074
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 21 August 2021
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TUPAB079	Using ER@CEBAF to Show that a Multipass ERL Can Drive an XFEL	FEL, controls, electron, acceleration	1555
	G. Perez-Segurana Cockcroft Institute, Lancaster University, Lancaster, United Kingdom I.R. Bailey, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom I.R. Bailey Lancaster University, Lancaster, United Kingdom R.M. Bodenstein, S.A. Bogacz, D. Douglas, Y. Roblin, T. Satogata JLab, Newport News, Virginia, USA T. Satogata ODU, Norfolk, Virginia, USA P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility as an option for a potential UK-XFEL. Energy Recovery enables multi-MHz FEL sources, for example, an X-ray FEL oscillator or regenerative amplifier FEL. Additionally, combining with external lasers and/or self-interaction would provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power for nuclear and particle physics applications. An opportunity exists to demonstrate the necessary point-to-parallel longitudinal matches to drive an XFEL and successfully energy recover at the upcoming 5-pass up, 5-pass down Energy Recovery experiment on CEBAF at JLab termed ER@CEBAF. We show candidate matches and simulations supporting the minimal necessary modifications to CEBAF this will require. This includes linearisation of the longitudinal phase space in the injector and a reduction in the dispersion of the arcs, both of which increase the energy acceptance of CEBAF. We expect to commence initial tests of these adaptations on CEBAF during 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB079
About •	paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021
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TUPAB099	Construction of an Infrared FEL at the Compact ERL	FEL, undulator, laser, electron	1608
	R. Kato, M. Adachi, S. Eguchi, K. Harada, N. Higashi, Y. Honda, T. Miyajima, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, T. Shioya, M. Tadano, R. Takai, O.A. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, M. Yamamoto KEK, Ibaraki, Japan R. Hajima QST, Tokai, Japan N.P. Norvell SLAC, Menlo Park, California, USA F. Sakamoto Akita National College of Technology, Akita, Japan M. Shimada HSRC, Higashi-Hiroshima, Japan
	Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)". The compact Energy Recovery Linac (cERL) has been in operation at KEK since 2013 to demonstrate ERL performance and develop ERL technology. Recently KEK has launched an infrared FEL project with a competitive funding. The purpose of this project is to build a mid-infrared FEL at the cERL, and to use that FEL as a light source for construction of the processing database required for industrial lasers. The FEL system is composed of two 3-m undulators and a matching section between them, and generates light with a maximum pulse energy of 0.1 micro-J at the wavelength of 20 microns with an 81.25 MHz repetition rate. The FEL is also expected to become a proof-of-concept machine for ERL base FELs for future EUV lithography.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB099
About •	paper received ※ 20 May 2021 paper accepted ※ 14 June 2021 issue date ※ 29 August 2021
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TUPAB115	Status Report of the Superconducting Free-Electron Laser FLASH at DESY	experiment, FEL, electron, undulator	1659
	J. Rönsch-Schulenburg, F. Christie, K. Honkavaara, M. Kuhlmann, S. Schreiber, R. Treusch, M. Vogt, J. Zemella DESY, Hamburg, Germany
	The free-electron laser in Hamburg (FLASH) is a high brilliance XUV and soft X-ray SASE FEL user-facility at DESY. FLASH’s superconducting linac can accelerate several thousand electron bunches per second in 10 Hz bursts of up to 800 µs length. The long bunch trains can be split in two parts and shared between two undulator beamlines. During 2020, FLASH supplied, in standard operation, up to 500 bunches at 10 Hz in two bunch trains with independent fill patterns and compression schemes. The FLASH2 undulator beamline comprises variable gap undulators that allow different novel lasing schemes. A third beamline accommodates the FLASHForward plasma wakefield acceleration experiment. We report on the FLASH operation in 2019 - 2021 and present a few highlights.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB115
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 19 August 2021
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TUPAB134	Linac-to-Booster Optimization Procedure Towards High Transmission for the Alba Injector	linac, booster, quadrupole, alignment	1703
	R. Muñoz Horta, D. Lanaia, E. Marín, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a third generation synchrotron light source that consists of 3 accelerators (Linac, Booster and Storage ring) and two transfer lines, Linac-to-Booster (LTB) and Booster-to-Storage (BTS). The ALBA accelerators team has defined a robust procedure that optimizes the beam performance from Linac to Booster in terms of transmission and stability. The implemented beam-based alignment and global orbit correction techniques have been investigated first in simulations and afterwards successfully implemented in the machine.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB134
About •	paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB178	Recommissioning of the CRYRING@ESR Electron Cooler	electron, experiment, target, acceleration	1816
	C. Krantz, Z. Andelkovic, C. Dimopoulou, W. Geithner, T. Hackler, F. Herfurth, R. Hess, M. Lestinsky, E. Menz, A. Reiter, J. Roßbach, C. Schroeder, A. Täschner, G. Vorobjev GSI, Darmstadt, Germany C. Brandau, S. Schippers Justus-Liebig-University Giessen, I. Physics Institute, Atomic and Molecular Physics, Giessen, Germany V. Hannen, D. Winzen Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany C. Weinheimer Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
	Funding: Parts of this work have been supported by the German Federal Ministry of Education and Research (BMBF) under contract numbers 05P19PMFA1 and 05P19RGFA1. The heavy-ion storage ring CRYRING has been recommissioned downstream of GSI’s ESR, which it complements as dedicated low-energy machine. A key element of CRYRING@ESR is its electron cooler, which features one of the coldest electron beams available. This enables efficient phase-space cooling and, in addition, provides very high energy resolution when used as internal electron target. We report on technical upgrades that have been made as part of the re-installation of the cooler at GSI/FAIR and share first results obtained after recommissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB178
About •	paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 25 August 2021
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TUPAB187	Reconstruction of U400M Cyclotron: Upgrade of U400M Cyclotron Magnetic Structure	cyclotron, extraction, MMI, ECR	1838
	I.A. Ivanenko, G.G. Gulbekyan, I.V. Kalagin, N.Yu. Kazarinov, N.F. Osipov, V.A. Semin JINR, Dubna, Moscow Region, Russia
	U400M isochronous cyclotron was created on the base of U300 classic cyclotron and is under operation at FLNR, JINR since 1996. At the present time the cyclotron electromagnet with 4 meter pole diameter needs a reconstruction that includes a replacement of magnet main coil, corrections of the magnetic field at the central region and at the extraction radius. For measurements and shimming of cyclotron magnetic field the automatic mapping system, based on 14 Hall probes, will be created.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB187

Paper

Title

Other Keywords

Page

MOXA03

Sirius Commissioning Results and Operation Status

MMI, storage-ring, alignment, injection

13

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

Sirius is a 4th generation 3 GeV synchrotron light source that has just finalized the first commissioning phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. This paper describes the main Accelerator Physics issues faced during the storage ring commissioning, methods that were used to work them out and the current operation status of the machine.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA03

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paper received ※ 20 May 2021 paper accepted ※ 10 June 2021 issue date ※ 16 August 2021

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MOPAB001

Power Deposition in Superconducting Dispersion Suppressor Magnets Downstream of the Betatron Cleaning Insertion for HL-LHC

proton, collimation, dipole, simulation

37

A. Waets, C. Bahamonde Castro, E. Belli, R. Bruce, N. Fuster-Martínez, A. Lechner, A. Mereghetti, S. Redaelli, M. Sabaté-Gilarte, E. Skordis
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
The power deposited in dispersion suppressor magnets downstream of the Large Hadron Collider (LHC) betatron cleaning insertion is governed by off-momentum particles scattered out of the primary collimators. In order to mitigate the risk of magnet quenches during periods of short beam lifetime in future High-Luminosity (HL-LHC) operation, new dispersion suppressor (DS) collimators are considered for installation (one per beam). In this paper, we present FLUKA simulations for both protons and Pb ions at 7 TeV, predicting the power deposition in the DS magnets, including the new higher-field dipoles 11T which are needed to integrate the collimator in the cold region next to the cleaning insertion. The simulated power deposition levels for the adopted HL-LHC collimator configuration and settings are used to assess the quench margin by comparison with the present estimated quench levels.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB001

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 16 August 2021

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MOPAB002

Risk of Halo-Induced Magnet Quenches in the HL-LHC Beam Dump Insertion

proton, insertion, collimation, betatron

41

J.B. Potoine, A. Apollonio, E. Belli, C. Bracco, R. Bruce, M. D’Andrea, R. García Alía, A. Lechner, G. Lerner, S. Morales Vigo, S. Redaelli, V. Rizzoglio, E. Skordis, A. Waets
CERN, Meyrin, Switzerland
F. Wrobel
IES, Montpellier, France

Funding: Research supported by the HL-LHC project
After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB002

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paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 22 August 2021

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MOPAB003

Machine Learning Analysis of Electron Cooler Operation for RHIC

luminosity, electron, scattering, GUI

45

X. Gu, A.V. Fedotov, D. Kayran
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A regression machine learning algorithm was applied to analyze the operation data of RHIC with electron cooler LEReC during the 2020 physics run. After constructing a black-box surrogate model from the XGBoost algorithm and plotting their partial dependency plots for different operation parameters, we can find the effects of an individual parameter on the RHIC luminosity and optimize it accordingly offline.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB003

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paper received ※ 14 May 2021 paper accepted ※ 25 May 2021 issue date ※ 11 August 2021

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MOPAB005

Studies for an LHC Pilot Run with Oxygen Beams

target, luminosity, MMI, proton

53

R. Bruce, R. Alemany-Fernández, H. Bartosik, M.A. Jebramcik, J.M. Jowett, M. Schaumann
CERN, Geneva, Switzerland

Motivated by the study of collective effects in small systems with oxygen-oxygen (O-O) collisions, and improvements to the understanding of high-energy cosmic ray interactions from proton-oxygen (p-O) collisions, a short LHC oxygen run during Run 3 has been proposed. This article presents estimates for the obtainable luminosity performance in these two running modes based on simulations of a typical fill. The requested integrated luminosity, projected beam conditions, data-taking and commissioning times are considered and a running scenario is proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB005

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

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MOPAB008

Exploiting the Beam-Beam Wire Demonstrators in the Next LHC Run 3

octupole, luminosity, experiment, quadrupole

65

A. Poyet
Université Grenoble Alpes, Grenoble, France
S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, A. Rossi, G. Sterbini
CERN, Geneva, Switzerland
K. Skoufaris
University of Crete, Heraklion, Crete, Greece

After the successful experiments performed during the LHC Run 2 with the Beam-Beam Wire demonstrators installed, on Beam 2, in the frame of the HL-LHC project, two of the four wire demonstrators were moved to Beam 1. The objective is to gain operational experience with the wire compensation also on that beam and therefore fully exploit the demonstrators’ potential. This paper proposes a numerical validation of the wire implementation using Run 3 scenarios and explores the optimization of those devices in that respect.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB008

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paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 11 August 2021

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MOPAB009

Review of the Fixed Target Operation at RHIC in 2020

target, experiment, controls, kicker

69

C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
As part of the Beam Energy Scan (BES) physics program, RHIC operated in Fixed Target mode at various beam energies in 2020. The fixed target experiment, achieved by scraping the beam halo of the circulating beam on a gold ring inserted in the beam pipe upstream of the experimental detectors, extends the range of the center-of-mass energy for BES. The machine configuration, control of rates, and results of the fixed target experiment operation in 2020 will be presented in this report.

Poster MOPAB009 [2.913 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB009

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paper received ※ 16 May 2021 paper accepted ※ 17 August 2021 issue date ※ 23 August 2021

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MOPAB010

RHIC Beam Energy Scan Operation with Electron Cooling in 2020

luminosity, electron, emittance, experiment

72

C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
RHIC provided Au-Au collisions at beam energies of 5.75 and 4.59 GeV/nucleon for the physics program in 2020 as a part of the Beam Energy Scan II experiment. The operational experience at these energies will be reported with emphasis on their unique features. These unique features include the addition of a third harmonic RF system to enable a large longitudinal acceptance at 5.75 GeV/nucleon, the application of additional lower frequency cavities for alleviating space charge effects, and the world-first operation of cooling with an RF-accelerated bunched electron beam.

Poster MOPAB010 [3.523 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB010

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paper received ※ 17 May 2021 paper accepted ※ 29 July 2021 issue date ※ 10 August 2021

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MOPAB013

Radiation to Electronics Impact on CERN LHC Operation: Run 2 Overview and HL-LHC Outlook

radiation, luminosity, electron, target

80

Y.Q. Aguiar, A. Apollonio, F. Cerutti, S. Danzeca, R. García Alía, G. Lerner, D. Prelipcean, M. Sabaté-Gilarte
CERN, Geneva 23, Switzerland

Funding: Research supported by the HL-LHC project
After the mitigation measures implemented during Run 1 (2010-2012) and Long Shutdown 1 (LS1, 2013-2014), the number of equipment failures due to radiation effects on electronics (R2E) leading to LHC beam dumps and/or machine downtime has been sufficiently low as to yield a minor impact on the accelerator performance. During Run 2 (2015-2018) the R2E related failures per unit of integrated luminosity remained below the target value of 0.5 events/fb-1, with the sole exception of the 2015 run during which the machine commissioning took place. However, during 2018, an increase in the failure rate was observed, linked to the increased radiation levels in the dispersion suppressors of the ATLAS and CMS experimental insertions, significantly affecting the Quench Protection System located underneath the superconducting magnets in the tunnel. This work provides an overview of the Run 2 R2E events during LHC proton-proton operation, putting them in the context of the related radiation levels and equipment sensitivity, and providing an outlook for Run 3 and HL-LHC operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB013

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

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MOPAB016

Small Longitudinal Emittance Setup in Injectors with Gold Beam for Beam Energy Scan in RHIC

emittance, luminosity, extraction, cavity

90

H. Huang, C.J. Gardner, C. Liu, V. Schoefer, K. Zeno
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In recent years, RHIC physics program calls for gold beam collisions with energies at and lower than the nominal RHIC injection energy. To get shorter bunches at the three higher energies (9.8GeV/c, 7.3GeV/c and 4.75GeV/c), RHIC 28MHz cavities were used. The longitudinal emittance out of injectors needs to fit in the 28MHz cavities in RHIC. At two lower energies (4.6 and 3.85 GeV/c), the 9MHz RF cavities were used, which set different requirements from injectors. Extensive beam studies were carried out to establish needed beam parameters, such as bunch intensities and longitudinal emittances. In general, enough intensity can be provided for all energies within the longitudinal emittance constraint. This paper summarizes the recent injector operation experiences for various energies.

Poster MOPAB016 [2.641 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB016

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paper received ※ 16 May 2021 paper accepted ※ 17 August 2021 issue date ※ 01 September 2021

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MOPAB023

Experimental Test of a New Method to Verify Retraction Margins Between Dump Absorbers and Tertiary Collimators at the LHC

experiment, alignment, beam-losses, emittance

115

C. Wiesner, W. Bartmann, C. Bracco, R. Bruce, J. Molson, M. Schaumann, C. Staufenbiel, J.A. Uythoven, M. Valette, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Meyrin, Switzerland

The protection of the tertiary collimators (TCTs) and the LHC triplet aperture in case of a so-called asynchronous beam dump relies on the correct retraction between the TCTs and the dump region absorbers. A new method to validate this retraction has been proposed, and a proof-of-principle experiment was performed at the LHC. The method uses a long orbit bump to mimic the change of the beam trajectory caused by an asynchronous firing of the extraction kickers. It can, thus, be performed with circulating beam. This paper reports on the performed beam measurements, compares them with expectations and discusses the potential benefits of the new method for machine protection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB023

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paper received ※ 19 May 2021 paper accepted ※ 25 August 2021 issue date ※ 24 August 2021

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MOPAB028

Using Machine Learning to Improve Dynamic Aperture Estimates

simulation, dynamic-aperture, collider, hadron

134

F.F. Van der Veken, M. Giovannozzi, E.H. Maclean
CERN, Geneva, Switzerland
C.E. Montanari
Bologna University, Bologna, Italy
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The dynamic aperture (DA) is an important concept in the study of nonlinear beam dynamics. Several analytical models used to describe the evolution of DA as a function of time, and to extrapolate to realistic time scales that would not be reachable otherwise due to computational limitations, have been successfully developed. Even though these models have been quite successful in the past, the fitting procedure is rather sensitive to several details. Machine Learning (ML) techniques, which have been around for decades and have matured into powerful tools ever since, carry the potential to address some of these challenges. In this paper, two applications of ML approaches are presented and discussed in detail. Firstly, ML has been used to efficiently detect outliers in the DA computations. Secondly, ML techniques have been applied to improve the fitting procedures of the DA models, thus improving their predictive power.

Poster MOPAB028 [1.764 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB028

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paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 12 August 2021

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MOPAB031

Development and Operation of Vacuum System for Rapid Cycling Synchrotron to Target Beam Transfer Line of China Spallation Neutron Source

vacuum, target, neutron, proton

145

J.M. Liu, Y.H. Guan, S.M. Liu, B. Tan, P.C. Wang
DNSC, Dongguan, People’s Republic of China
H. Dong
IHEP, Beijing, People’s Republic of China
H.Y. He, T. Huang
IHEP CSNS, Guangdong Province, People’s Republic of China

China Spallation Neutron Source (CSNS) is a major scientific project during the National Eleventh Five-Year Plan. It consists of a negative hydrogen ion linear accelerator, a rapid cycling synchrotron ( RCS), a linac to RCS beam transfer line (LRBT), an RCS to target beam transfer line (RTBT), and a target station. As an important part of CSNS, the RTBT connects the rapid cycling synchrotron and the target window. This paper described the design requirements, technical solutions, and operating conditions of the vacuum system for the CSNS RCS to target beam transfer line. In addition, the fast valve protection system and its verification results were also expounded. The CSNS has been in operation for over three years, during this period, the beam power has been gradually improved from 10KW to 100KW, and the vacuum system for RTBT has been operating stably.

Poster MOPAB031 [0.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB031

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paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 25 August 2021

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MOPAB036

Different Operation Regimes at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)

optics, lattice, electron, storage-ring

163

A.I. Papash, M. Brosi, E. Huttel, A. Mochihashi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

The KIT storage ring KARA operates in a wide energy range from 0.5 to 2.5 GeV. Different operation modes have been implemented at KARA, so far, the double-bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, different versions of low-compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low-alpha optics has been simulated, tested and implemented in a wide operational range of the storage ring and is now routinely used at 1.3 GeV for studies of beam bursting effects caused by coherent synchrotron radiation in the THz frequency range. Different non-linear effects, in particular residual high-order components of the magnetic field, generated in high-field superconducting wigglers have been studied and cured. Based on good agreement between computer simulations and experiments, a new operation mode at high vertical tune was implemented. The beam performance during user operation as well as at low-alpha regimes has been improved. A specific optic with negative compaction factor was simulated, tested and is in operation.

Poster MOPAB036 [1.477 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB036

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paper received ※ 13 May 2021 paper accepted ※ 08 June 2021 issue date ※ 29 August 2021

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MOPAB037

On Possibility of Alpha-buckets Detecting at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)

storage-ring, optics, synchrotron, electron

167

A.I. Papash, T. Boltz, M. Brosi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

Computer studies of longitudinal motion have been performed with the objective to estimate the possibility of detection of alpha-buckets at the KIT storage ring KARA (Karlsruhe Research Accelerator). The longitudinal equations of motion and the Hamiltonian were expanded to high order terms of the energy deviation of particles in a beam. Roots of third order equation for three leading terms of momentum compaction factor and free energy independent term were derived in a form suitable for analytical estimations. Averaged quadratic terms of closed orbit distortions caused by misalignment of magnetic elements in a ring lead to orbit lengthening independent of particle energy deviation. Particle transverse excursions were estimated and are taken into account. Simulations have been bench-marked on existing experiments at Metrology Light Source (MLS) in Berlin (Germany) and SOLEIL (France). Parameters of three simultaneous beams and alpha buckets at MLS and SOLEIL have been reproduced with high accuracy. A computer model of KARA was used to predict behavior and the dynamics of possible simultaneous beams in the ring.

Poster MOPAB037 [1.269 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB037

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paper received ※ 11 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021

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MOPAB044

Gas Bremsstrahlung Measurements in the Advanced Photon Source Storage Ring

photon, radiation, detector, injection

193

J.C. Dooling, A.R. Brill, J.R. Calvey
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357.
In the Advanced Photon Source Upgrade storage ring (SR), small-aperture vacuum chambers provide limited conductance for pumping. Non-evaporable getter (NEG) coatings will be used in the SR to support the vacuum. Ion pumps and cold-cathode gauges are typically located away from the vacuum chamber transporting the beam. Measuring gas bremsstrahlung (GB) photons in low-conductance chambers provides a method to determine the pressure at the beam location. We report on GB measurements made in the ID-25 beamline. A Pb:Glass calorimeter radiator generates Cherenkov radiation when high-energy photons cause pair-production within the glass. A photomultiplier tube converts the light pulses to electrical signals. Data was obtained during normal machine operations starting in January 2020. Data collection was facilitated using a 4-channel ITech Beam Loss Monitor FPGA that allows for control of thresholds and attenuation settings in both counting and pulse-height acquisition modes. Count rates and spectra were recorded for the three primary fill patterns typically used during SR operations as well as during gas injection experiments; results of these measurements will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB044

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paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021

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MOPAB051

Operation of the ESRF Booster with the New EBS Storage Ring

emittance, booster, SRF, injection

221

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

The Extremely Brilliant Source (EBS) has replaced the old ESRF Storage Ring (SR) during the 2019 one-year shutdown. The injector chain, composed of a Linac, a booster synchrotron, and two transfer lines, was not replaced. Nevertheless, some major hardware upgrades were anticipated prior to the long shutdown to ensure its long-term reliability. The shutdown interventions focused on reducing the machine circumference to cope with the new RF frequency of the SR. The status of the upgraded booster will be presented with a focus on the strategy used to lower horizontal emittance especially via emittance exchange.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB051

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paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021

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MOPAB077

Anomaly Detection in Accelerator Facilities Using Machine Learning

power-supply, GUI, experiment, detector

304

A. Das
Stanford University, Stanford, California, USA
M. Borland, L. Emery, X. Huang, H. Shang, G. Shen
ANL, Lemont, Illinois, USA
D.F. Ratner
SLAC, Menlo Park, California, USA
R.M. Smith, G.M. Wang
BNL, Upton, New York, USA

Synchrotron light sources are user facilities and usually run about 5000 hours per year to support many beamlines operations in parallel. Reliability is a key parameter to evaluate machine performance. Even many facilities have achieved >95% beam reliability, there are still many hours of unscheduled downtime and every hour lost is a waste of operation costs along with a big impact on individual scheduled user experiments. Preventive maintenance on subsystems and quick recovery from machine trips are the basic strategies to achieve high reliability, which heavily depends on experts’ dedication. Recently, SLAC, APS, and NSLS-II collaborated to develop machine-learning-based approaches aiming to solve both situations, hardware failure prediction and machine failure diagnosis to find the root sources. In this paper, we report our facility operation status, development progress, and plans.

Poster MOPAB077 [1.240 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB077

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 01 September 2021

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MOPAB079

Experience of the First Six Years Operations and Plans in NSlS-II

cavity, MMI, feedback, vacuum

308

G.M. Wang
BNL, Upton, New York, USA

NSLS-II is a 3 GeV third-generation synchrotron light source at BNL. The storage ring was commissioned in 2014 and began its routine operations in the December of the same year. Since then, we have been continuously installing and commissioning new insertion devices, their front-ends, and beamlines. At this point, the facility hosts 28 operating beamlines from various radiation sources, including damping wiggler, IVU, EPU, 3PW, and bending magnets for infrared beamlines. Over the past six years, the storage ring performance continuously improved, including 500 mA with limited insertion devices close due to RF power limitation and routinely 400 mA top off operation, >95% operation reliability, maintenance of beam motion short- and long-term stability. In this paper, we report NSLS-II accelerator operations experience and plans for future facility developments.

Poster MOPAB079 [2.064 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB079

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paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021

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MOPAB082

Implementation of Using IGBT Switch Based Pulser for TPS Booster Extraction Kicker

extraction, kicker, booster, injection

315

C.-S. Fann, H.-P. Chang, C.L. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.-K. Lin, K.L. Tsai, C.Y. Wu
NSRRC, Hsinchu, Taiwan

A pair of thyratron-switch-based pulse-forming-network (PFN) pulser has been operating successfully in the past 5 years for TPS booster extraction kickers. In order to improve the flattop of drive-current pulse and to extend possible electron bunch train adjusting knob required, an IGBT-switch-based pulser has been designed, fabricated, and installed onto the TPS booster for its characteristics verification. In this report, the overall technical considerations for the pulser upgrade is described and its beam commissioning results is given for illustration purpose.

Poster MOPAB082 [0.621 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB082

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paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 13 August 2021

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MOPAB091

Injection Section Upgrading with the Septum-Magnet Replacement in KEK-PF Ring

injection, septum, vacuum, storage-ring

342

C. Mitsuda, K. Harada, N. Higashi, T. Honda, Y. Kobayashi, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, M. Tadano, R. Takai, H. Takaki, Y. Tanimoto, T. Uchiyama, A. Ueda
KEK, Ibaraki, Japan

In 2015, the water leakage happened at the cooling pipe of the in-vacuum septum magnet installed into the injection point. Because the maintenance of the leakage needed the total replacement of the magnet, the water circulation was stopped permanently, and accordingly, the light absorber was installed upstream in the storage ring to prevent the synchrotron light of the bending magnet from coming to the septum wall. This treatment temporally worked well, but the beam injection efficiency was decreased to about 30% due to the physical aperture narrowed by the absorber. With the desired replacement of septum magnet to maintainable out-vacuum type, the injection section upgrading was simultaneously planned to recover and improve the injection efficiency. In this upgrade, the injection beam is closed to the stored beam more than before by adapting the thinner septum structure as a way to improve the injection efficiency. And some new ideas are introduced in the part of monitor and beam duct, for example, realtime beam monitor, thinner Inconel duct. The detailed design of the upgraded injection section and technical points will be reviewed in this conference.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB091

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paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 02 September 2021

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MOPAB093

Operational Status of Photon Factory Light Sources

injection, radiation, electron, vacuum

350

T. Honda, Y. Kobayashi, C. Mitsuda, S. Nagahashi, R. Takai, H. Takaki
KEK, Ibaraki, Japan

One of the recent topics of Photon Factory light sources, PF-ring and PF-AR, is a construction of a GeV-class beamline for testing detectors at the PF-AR. The bremsstrahlung photons generated by a thin carbon wire are brought to a copper target to generate e⁺e⁻ pairs. Sufficient count rates can be expected when the thin wire touching halo of the stored beam, and the test beamline can be used without disturbing the synchrotron radiation experiments. In addition to the usual 6.5-GeV operation, a low-energy operation at 5-GeV was started recently at PF-AR to secure operation time by saving electricity costs. At the PF-ring, the injection section has been upgraded with the septum-magnet replacement. By the top-up injection and improved bunch feedback, the hybrid-fill mode operation has become convenient for both single-bunch users and multi-bunch users, and about 30% or 40% of the user time is scheduled as the hybrid-fill mode now.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB093

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paper received ※ 21 May 2021 paper accepted ※ 25 May 2021 issue date ※ 13 August 2021

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MOPAB108

ESRF-EBS 352.37 MHz Radio Frequency System

cavity, SRF, MMI, HOM

395

J. Jacob, P.B. Borowiec, A. D’Elia, G. Gautier, V. Serrière
ESRF, Grenoble, France

The ESRF 352 MHz Radio Frequency (RF) system has been upgraded and tailored to the new 4th Generation Extremely Brilliant Source EBS, that was installed in 2019 and commissioned in 2020. The five former five-cell cavities were replaced with 13 single cell strongly HOM damped cavities that were developed in house, 10 of which are powered from existing 1 MW klystron transmitters. The remaining three cavities are individually fed by three 150 kW solid state amplifiers. All this required a reconstruction in record time of an elaborate WR2300 waveguide network. The low level RF system as well as the cavity and transmitter control system have been rebuilt. The RF design, commissioning and operation experience will be reported, including plans for a 4th harmonic RF system for bunch lengthening to further improve the performance of the new EBS ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB108

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 02 September 2021

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MOPAB124

APS Booster Injection Horizontal Trajectory Control Upgrade

injection, controls, booster, timing

449

C. Yao, J.R. Calvey, G.I. Fystro, A.F. Pietryla, H. Shang
ANL, Lemont, Illinois, USA

Funding: * Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO₂-O6CH11357.
The APS booster is a 7-GeV electron synchrotron with a 0.5-second cycle. The booster runs a set of injection control programs that correct the beam trajectory in the horizontal and longitudinal planes, and the betatron tunes. Recently we developed a single-turn BPM controllaw program for horizontal trajectory control to replace the previous FFT based horizontal controllaw program. We present the system configuration and results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB124

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paper received ※ 15 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021

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MOPAB128

Operational Use of Pinger Magnets to Counter Stored Beam Oscillations During Injection at Diamond Light Source

injection, kicker, diagnostics, storage-ring

459

R.T. Fielder, M. Apollonio, I.P.S. Martin
DLS, Oxfordshire, United Kingdom

Diamond uses a four kicker bump injection scheme. Due to a variety of factors it has become more difficult to perfectly match the four kicks while maintaining injection efficiency, resulting in some disturbance to the stored beam during top-up. This has consequences for beamlines which may see degraded beam quality during injections. A gating signal is provided, but this is not appropriate for all experiments, and in any case ideally would not be required. The disturbance to the stored beam can be partly controlled using the existing diagnostic pinger magnets installed in the storage ring. We present here a comparison of different compensation schemes and tests with beamlines, along with initial experiences operating during user beam time. Use of these magnet also provides proof of principle for any future, purpose-built compensation kickers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB128

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paper received ※ 18 May 2021 paper accepted ※ 20 May 2021 issue date ※ 01 September 2021

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MOPAB140

Gas Sheet Ionization Diagnostic for High Intensity Electron Beams

diagnostics, electron, detector, vacuum

489

N.P. Norvell, G. Andonian, T.J. Campese, A.-L.M.S. Lamure, M. Ruelas, A.Yu. Smirnov
RadiaBeam, Santa Monica, California, USA
N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
J.K. Penney
UCLA, Los Angeles, California, USA
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by DOE grant DE-SC0019717
The characterization of high intensity charged particle beams in a minimally interceptive, and non-destructive manner is performed using an ionization diagnostic. In this application, a neutral gas is tailored into a thin sheet, or curtain-like, distribution at the interaction point with an electron beam. The electron beam ionizes the neutral gas in localized space, leaving a footprint of the beam transverse distribution. The ion cloud is subseqeuntly imaged with a series of electrostatic lenses to a detector plane. The resultant image is used in a reconstruction algorithm to reconstruct the beam profile at the interaction point. In this paper, we present progress on the development of this diagnostic for the characterization of high charge, 10GeV electron beams with small transverse distributions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB140

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paper received ※ 20 May 2021 paper accepted ※ 10 June 2021 issue date ※ 01 September 2021

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MOPAB174

Foil Hits Reduction by Minimizing Injection Beam Size at the Foil in J-PARC RCS

injection, proton, scattering, beam-losses

590

P.K. Saha, H. Harada, K. Okabe, F. Tamura, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
H. Hotchi
KEK, Tokai, Ibaraki, Japan

Funding: Pranab Kumar Saha
The uncontrolled beam loss caused by the foil scattering of the circulating beam during multi-turn charge-exchange injection is one of the main sources for high residual radiation at the injection area of J-PARC 3-GeV rapid cycling synchrotron. We studied to reduce foil hits of the circulating beam by minimizing the vertical injection beam size at the foil and using a smaller vertical foil size. The vertical foil size was reduced according to the injection beam size by maintaining the stripping efficiency. As a result, the number of circulating beam passing through foil was significantly reduced due to smaller foil size. The simulation and measurement results of the foil hits reduction are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB174

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paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021

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MOPAB183

A Framework for Dynamic Aperture Studies for Colliding Beams in the High-Luminosity Large Hadron Collider

luminosity, simulation, beam-beam-effects, sextupole

620

S. Kostoglou, H. Bartosik, Y. Papaphilippou, G. Sterbini
CERN, Geneva, Switzerland

During the last physics run of the Large Hadron Collider (LHC), Dynamic Aperture (DA) studies have been successfully employed to optimize the accelerator’s performance by guiding the selection of the beam and machine parameters. In this paper, we present a framework for single-particle tracking simulations aiming to refine the envisaged operational scenario of the future LHC upgrade, the High-Luminosity LHC (HL-LHC), including strong non-linear fields such as beam-beam interactions. The impact of several parameters and beam processes during the cycle is initially illustrated with frequency maps and then quantified with DA studies.

Poster MOPAB183 [2.789 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB183

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paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 23 August 2021

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MOPAB203

Benchmark of Superconducting Cavity Models at SNS Linac

cavity, linac, superconducting-cavity, simulation

671

A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy.
A benchmark of superconducting cavity models against Time-of-Flight measurements at the SNS linac is presented. The superconducting part of SNS linac (SCL) includes 81 RF cavities that accelerates H⁻ beam from 185.6 MeV to the final energy of 1 GeV. During the operation some of cavities can become unstable, and its amplitudes should be reduced, or they should be completely switched off. In this case, the SCL is retuned by using a linac simulation code. This simulation tool relay on an accuracy of the superconducting cavity model. This paper describes the comparison of the measured beam acceleration by one of the SCL cavities and simulations of this process. Different cavity models are used in simulations. The subject of this study is limited to the longitudinal beam dynamics, so no effects on transverse beam characteristics have been considered.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB203

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paper received ※ 14 May 2021 paper accepted ※ 20 May 2021 issue date ※ 24 August 2021

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MOPAB208

LLRF Measurements and Cu-plating at the First-of-Series Cavity Section of the Alvarez 2.0 at GSI

cavity, DTL, simulation, vacuum

686

M. Heilmann, T. Dettinger, X. Du, L. Groening, S. Mickat, A. Rubin
GSI, Darmstadt, Germany

The Alvarez 2.0 will replace the existing post-stripper DTL of the GSI UNILAC. Today’s GSI comprises the UNILAC and the synchrotron SIS18 and is going to serve as the injector chain for the Facility of Antiproton and Ion Research (FAIR). The new Alvarez-type DTL is operated at 10⁸.4 MHz providing acceleration from 1.4 MeV/u to 11.4 MeV/u along a total length of 55 meters. The first-of-series (FoS) cavity section has 12 RF-gaps along a total length of 1.9 m. It is the first cavity section of the new DTL. All main components were delivered in 2019, followed by successful SAT and installation of the 11 drift tubes and copper-plating. Completion of first low level RF-measurements prior to copper plating and the subsequent plating are major project milestones. These proceedings report on the results and compares them to simulation using CST Microwave Studio.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB208

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 22 August 2021

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MOPAB217

A Storage Ring for MESA

target, experiment, optics, simulation

719

C.P. Stoll, A. Meseck
KPH, Mainz, Germany
B. Ledroit
HIM, Mainz, Germany

The Mainz Energy-recovering Superconducting Accelerator (MESA) is an Energy Recovery Linac (ERL) facility under construction at the Johannes Gutenberg-University in Mainz. It provides the opportunity for precision physics experiments with a 1 mA c.w. electron beam in its initial phase. In this phase experiments with unpolarised, high density 10¹⁹ atoms cm² gas jet targets are foreseen at the Mainz Gas Internal Target Experiment (MAGIX). To allow experiments with thin polarised gas targets with sufficiently high interaction rates in a later phase, the beam current has to be increased to up to 100 mA, which would pose significant challenges to the existing ERL machine. Thus, it is proposed here to use MESA in pulsed operation with a repetition rate of several kHz to fill a storage ring, providing a quasi c.w. beam current to a thin gas target. For this purpose, the existing optics need to be extended and adapted, a suitable injection and extraction scheme is necessary and beam target interaction must be investigated. First considerations on these topics are presented here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB217

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paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 21 August 2021

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MOPAB228

Introducing two Energy-Correction Schemes at DELTA

storage-ring, simulation, closed-orbit, injection

740

S. Kötter
DELTA, Dortmund, Germany

At DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University, two methods to correct the beam energy of the storage ring have been tested. The first one is capable of maintaining the current beam energy. The second method is used to find the optimal orbit length. Here, the ideas behind both methods are explained and first test results are presented. Numerical studies are shown together with measurement results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB228

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

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MOPAB229

Compensations of Third-Order Resonances in J-PARC MR

resonance, sextupole, optics, survey

744

T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa
KEK, Tokai, Ibaraki, Japan

The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 10¹³ protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (ν_x, ν_y) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is ν_x-2ν_y=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3ν_x=64 and ν_x+2ν_y=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229

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paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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MOPAB253

Comparison of Transfer Map Derivation Methods for Static Magnetic Fields

multipole, quadrupole, lattice, extraction

799

J.A. Crittenden, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811.
We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 13 August 2021

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MOPAB270

Beam Dynamics Studies in a Standing Wave Ka-band Linearizer

electron, emittance, bunching, simulation

857

J. Scifo, M. Behtouei, L. Faillace, M. Ferrario, A. Giribono, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati, Italy
M. Migliorati
INFN-Roma1, Rome, Italy
M. Migliorati
Sapienza University of Rome, Rome, Italy
G. Torrisi
INFN/LNS, Catania, Italy

Next-generation FEL user facilities require high-quality electron beams with kA peak current. The combination of a high brightness RF injector and a magnetic compression stage represents a very performant solution in terms of electron beam emittance and peak current. One of the important issues is the design of a proper device that acts as a linearizer for the beam longitudinal phase space. Recently, the design of a SW Ka band RF accelerating structure has been proposed with promising results. The paper reports on electron beam dynamics studies in the described RF structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB270

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paper received ※ 19 May 2021 paper accepted ※ 29 August 2021 issue date ※ 26 August 2021

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MOPAB272

Consideration the Prospects of Beam Diagnostic System Upgrade in the Transport Channels of Injection Complex VEPP-5

positron, electron, injection, diagnostics

860

K.V. Astrelina, F.A. Emanov
BINP SB RAS, Novosibirsk, Russia
F.A. Emanov
NSU, Novosibirsk, Russia

Transport electron and positron channels from linear accelerator to storage ring of Injection Complex VEPP-5 (BINP, Novosibirsk) have complicated 3D configuration and equipped only with luminophore screens as a beam test. For the regular machine operations the non-destructive beam diagnostic system is required to adjust the electron and positron beam trajectories and minimize the beam losses. The proposal of new beam position monitors (BPM) assembling is considered. Newly added BPMs allow one to control the beam trajectory during operations. Collecting beam position data in several points makes it possible to calculate and correct the beamline parameters: Twiss parameters, dispersion, beam energy variations. The possible configuration of the new BPMs placing is suggested and the rate of beam loss reducing due the additional diagnostics is estimated.

Poster MOPAB272 [1.164 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB272

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paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 02 September 2021

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MOPAB288

Real-Time Edge AI for Distributed Systems (READS): Progress on Beam Loss De-Blending for the Fermilab Main Injector and Recycler

network, real-time, distributed, FPGA

912

K.J. Hazelwood, M.R. Austin, M.A. Ibrahim, V.P. Nagaslaev, A. Narayanan, D.J. Nicklaus, A.L. Saewert, B.A. Schupbach, K. Seiya, R.M. Thurman-Keup, N.V. Tran
Fermilab, Batavia, Illinois, USA
H. Liu, S. Memik, R. Shi, M. Thieme
Northwestern University, Evanston, Illinois, USA
A. Narayanan
Northern Illinois University, DeKalb, Illinois, USA

The Fermilab Main Injector enclosure houses two accelerators, the Main Injector and Recycler. During normal operation, high intensity proton beams exist simultaneously in both. The two accelerators share the same beam loss monitors (BLM) and monitoring system. Beam losses in the Main Injector enclosure are monitored for tuning the accelerators and machine protection. Losses are currently attributed to a specific machine based on timing. However, this method alone is insufficient and often inaccurate, resulting in more difficult machine tuning and unnecessary machine downtime. Machine experts can often distinguish the correct source of beam loss. This suggests a machine learning (ML) model may be producible to help de-blend losses between machines. Work is underway as part of the Fermilab Real-time Edge AI for Distributed Systems Project (READS) to develop a ML empowered system that collects streamed BLM data and additional machine readings to infer in real-time, which machine generated beam loss.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB288

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paper received ※ 19 May 2021 paper accepted ※ 29 July 2021 issue date ※ 13 August 2021

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MOPAB296

Statistical Analysis of 2D Single-Shot PPRE Bunch Measurements

photon, radiation, diagnostics, storage-ring

939

M. Koopmans, J.-G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz
HZB, Berlin, Germany

The pulse picking by resonant excitation (PPRE) method* is used to realize pseudo single-bunch radiation from a complex filling pattern at the BESSY II storage ring. The PPRE bunch is excited in the horizontal plane by a quasi-resonant incoherent perturbation to increase the emittance of this bunch**. Therefore, the synchrotron light of the PPRE bunch can be separated by collimation from the radiation of the main bunch train at dedicated beamlines for timing users. The properties of the PPRE bunch depend on the storage ring settings and on the excitation parameters. It is not trivial to distinguish between the wanted intrinsic bunch broadening and an additional position fluctuation of the PPRE bunch. Using the potential of the new diagnostics beamline with the possibility to observe an additional spatial dimension with a fast streak camera, we introduce a new method to study the properties of the PPRE bunch***. Applying a statistical analysis to a series of single-turn images enables distinguishing between horizontal orbit motion and the broadening of the bunch due to the excitation. Measurements are presented and the results are compared with data from the BPM system.
* K. Holldack et al., Nature Commun. 5 (2014) 4010.
** J.-G. Hwang et al., Nucl. Instrum. Methods A940 (2019) 387.
*** G. Schiwietz et al., Nucl. Instrum. Methods A990 (2021) 164992.

Poster MOPAB296 [2.074 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB296

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 23 August 2021

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MOPAB313

Argonaut - A Robotic System for Cryogenic Environments

detector, diagnostics, cryogenics, electron

966

W. Pellico, N.M. Curfman, M. Wong-Squires
Fermilab, Batavia, Illinois, USA

Funding: Department of Energy
Fermilab and the HEP community invest significant resources into liquid argon detectors. The largest and most expensive of these detectors will be located in the Deep Underground Neutrino Experiment (DUNE). However, recent experiences have shown that there are limited avenues of monitoring, intervention, and interaction in the internal liquid environment. This proposal shows a technological path that could provide a valuable tool to ensure or at least improve the management of these HEP detectors. The development of a robotic system named Argonaut will demonstrate several technologies including 1) demonstration of suitable mobility of a small robotic device at liquid argon temperatures, 2) demonstration of wireless communication, 3) demonstration of improved diagnostics capabilities - such as tunable optics with motion control, 4) demonstration of interconnectivity of a robotic system with hardware residing within the detector. This initial research will be a seed for extended development in cold robotics and associated technologies. This work will allow FNAL to contribute a significant technology capability to recent efforts to cryogenic detector operations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB313

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paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 25 August 2021

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MOPAB314

Surrogate Modeling for MUED with Neural Networks

electron, experiment, gun, network

970

D.J. Monk, S. Biedron, M.A. Fazio, M. Martínez-Ramón, S.I. Sosa Guitron
UNM-ECE, Albuquerque, USA
M. Babzien, K.A. Brown, M.A. Palmer, J. Tao
BNL, Upton, New York, USA
D. Martin, M.E. Papka
ANL, Lemont, Illinois, USA
T. Talbott
UNM-ME, Albuquerque, New Mexico, USA

Electron diffraction is among the most complex and influential inventions of the last century and contributes to research in many areas of physics and engineering. Not only does it aid in problems like materials and plasma research, electron diffraction systems like the MeV ultra-fast electron diffraction(MUED) instrument at the Brookhaven National Lab(BNL) also present opportunities to explore/implement surrogate modeling methods using artificial intelligence/machine learning/deep learning algorithms. Running the MUED system requires extended periods of uninterrupted runtime, skilled operators, and many varying parameters that depend on the desired output. These problems lend themselves to techniques based on neural networks(NNs), which are suited to modeling, system controls, and analysis of time-varying/multi-parameter systems. NNs can be deployed in model-based control areas and can be used simulate control designs, planned experiments, and to simulate employment of new components. Surrogate models based on NNs provide fast and accurate results, ideal for real-time control systems during continuous operation and may be used to identify irregular beam behavior as they develop.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB314

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paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 15 August 2021

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MOPAB320

The CMS ECAL Enfourneur: A Gigantic Machine with a Soft Touch

controls, alignment, insertion, experiment

986

V. Pettinacci
INFN-Roma, Roma, Italy

The electromagnetic calorimeter (ECAL) of the CMS experiment at the LHC is composed of 75848 scintillating lead tungstate crystals arranged in a barrel section and two endcaps. The barrel part is made of 36 supermodules (SM), 2.7 tons each, and is installed inside the CMS magnet. There are 18 SMs on each side of CMS, with each SM containing 1700 crystals. During Long Shutdown 3, all ECAL SMs must be extracted to refurbish the electronics in preparation for HL-LHC. A dedicated machine called the "Enfourneur" is used to extract and re-insert the SMs inside CMS, with a required accuracy of about 1mm. In order to speed up the extraction and insertion process, two Enfourneurs will be employed, operating in parallel on both sides. In view of the purchase of the second Enfourneur, the design has been improved, starting from the feedback of past operations. The improvements to the new Enfourneur design include increased space for the operators, optimization of the operations and the controls with the use of electric motors, and an updated alignment system. Handling plans inside the CMS cavern have been defined in order to be compliant with the rest of CMS structures and procedures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB320

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paper received ※ 11 May 2021 paper accepted ※ 17 August 2021 issue date ※ 20 August 2021

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MOPAB334

Status and Recent Development of FAIR Ring RF Systems

cavity, LLRF, power-supply, status

1037

U. Laier, R. Balß, C. Christoph, M. Frey, P. Hülsmann, H. Klingbeil, H.G. König, D.E.M. Lens, J.S. Schmidt, A. Stuhl, K.G. Thomin, T. Winnefeld
GSI, Darmstadt, Germany
H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: GSI Helmholtzzentrum für Schwerionenforschung GmbH
Five different Ring RF Systems are required for the operation of FAIR (Facility for Antiproton and Ion Research). These systems have to operate at frequencies between 310 kHz and 3.2 MHz, with gap voltages up to 40 kVp and duty cycles from 5·10^-4 up to cw. All systems will be realized using inductively loaded (ferrite or magnetic alloy) cavities driven by tetrode-based amplifiers fed by switch-mode power supplies. To stabilize the amplitude, resonance frequency and phase, versatile digital feedback and feedforward control will be used. This contribution will present the latest development on the power part and the LLRF of the four RF systems of the SIS100 (SIS100 Acceleration, SIS100 Bunch Compression, SIS100 Barrier Bucket and SIS100 Longitudinal Feedback) as well as the CR Debuncher system which is part of the Collector Ring. The progress of these systems varies by a large degree. This note will give an overview regarding the status of the design, procurement, realization, testing, optimization, commissioning and preparation for installation of these RF systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB334

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paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021

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MOPAB335

SNS Warm Linac Circulator Breakdown Considerations for the PPU Project

linac, simulation, DTL, proton

1041

G.D. Toby, Y.W. Kang, S.-H. Kim, S.W. Lee, J.S. Moss
ORNL, Oak Ridge, Tennessee, USA

Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
Multipacting in accelerating structures is a complex phenomenon about which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures which have a higher thermal capacity, and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Benchmarking of the peak electric fields in these structures, benefits of material processing and possible techniques for reducing or eliminating multipacting activities are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB335

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paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 23 August 2021

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MOPAB340

Experimental Tests with the First Segment of ESS-Bilbao RFQ Linac

rfq, vacuum, simulation, experiment

1054

J.L. Muñoz, I. Bustinduy, A. Conde, N. Garmendia, P.J. González, J. Martin, A. Zugazaga
ESS Bilbao, Zamudio, Spain

The ESS-Bilbao RFQ is an assembly of four segments, each one about 800 mm in length. The first segment has been manufactured before the others, so it could be thoroughly tested in order to validate the chosen technological approach for the RFQ, as it uses polymeric vacuum gaskets and bolts instead of brazing. In this paper we report on the tests run with the segment and their results. Vacuum tests, metrology measurements, low power RF tests as well as extensive tuning tests measuring the cavity resonant quadrupolar frequency as a function of cooling water temperature have been done. Experimental results are compared to the expected values obtained from numerical simulations. We describe the experimental set-ups for the measurements and the simulations. Results are analyzed with the aim of validating the design, and also to provide predictions for tuning and operation of the whole RFQ. As a consequence of the positive results of the tests reported here, the remaining segments have already been tendered.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB340

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paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 20 August 2021

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MOPAB341

First C-Band High Gradient Cavity Testing Results at LANL

cavity, proton, GUI, klystron

1057

E.I. Simakov, R.L. Fleming, D. Gorelov, T.A. Jankowski, M.F. Kirshner, J.W. Lewellen, J.D. Pizzolatto, M.E. Schneider, T. Tajima
LANL, Los Alamos, New Mexico, USA
X. Lu, E.A. Nanni, S.G. Tantawi
SLAC, Menlo Park, California, USA
M.E. Middendorf
ANL, Lemont, Illinois, USA

Funding: Los Alamos National Laboratory LDRD Program.
This poster will report the results of high gradient testing of the two proton β=0.5 C-band accelerating cavities. The cavities for proton acceleration were fabricated at SLAC and tested at high gradient C-band accelerator test stand at LANL. One cavity was made of copper, and the second was made of a copper-silver alloy. LANL test stand was constructed around a 50 MW, 5.712 GHz Canon klystron and is capable to provide power for conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. These β=0.5 C-band cavities were the first two cavities tested on LANL C-band test stand. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB341

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paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 30 August 2021

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MOPAB344

Machine Learning Models for Breakdown Prediction in RF Cavities for Accelerators

cavity, network, vacuum, linac

1068

C. Obermair, A. Apollonio, T. Cartier-Michaud, N. Catalán Lasheras, L. Felsberger, W.L. Millar, W. Wuensch
CERN, Geneva, Switzerland
C. Obermair, F. Pernkopf
TUG, Graz, Austria

Radio Frequency (RF) breakdowns are one of the most prevalent limits in RF cavities for particle accelerators. During a breakdown, field enhancement associated with small deformations on the cavity surface results in electrical arcs. Such arcs degrade a passing beam and if they occur frequently, they can cause irreparable damage to the RF cavity surface. In this paper, we propose a machine learning approach to predict the occurrence of breakdowns in CERN’s Compact LInear Collider (CLIC) accelerating structures. We discuss state-of-the-art algorithms for data exploration with unsupervised machine learning, breakdown prediction with supervised machine learning, and result validation with Explainable-Artificial Intelligence (Explainable AI). By interpreting the model parameters of various approaches, we go further in addressing opportunities to elucidate the physics of a breakdown and improve accelerator reliability and operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB344

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paper received ※ 20 May 2021 paper accepted ※ 16 July 2021 issue date ※ 11 August 2021

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MOPAB345

Machine Learning with a Hybrid Model for Monitoring of the Protection Systems of the LHC

monitoring, superconducting-magnet, dipole, machine-protect

1072

C. Obermair, A. Apollonio, Z. Charifoulline, M. Maciejewski, A.P. Verweij
CERN, Geneva, Switzerland
C. Obermair, F. Pernkopf
TUG, Graz, Austria

The LHC is the world’s largest particle accelerator and uses a complex set of sophisticated and highly reliable machine protection systems to ensure a safe operation with high availability for particle physics production. The data gathered during several years of successful operation allow the use of data-driven methods to assist experts in finding anomalies in the behavior of those protection systems. In this paper, we derive a model that can extend the existing signal monitoring applications for the LHC protection systems with machine learning. Our hybrid model combines an existing threshold-based system with a SVM by using signals, manually validated by experts. Even with a limited amount of data, the SVM learns to integrate the expert knowledge and contributes to a better classification of safety-critical signals. Using this approach, we analyze historical signals of quench heaters, which are an important part of the quench protection system for superconducting magnets. Particularly, it is possible to incorporate expert decisions into the classification process and to improve the failure detection rate of the existing quench heater discharge analysis tool.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB345

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paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 01 September 2021

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MOPAB359

Operational Experience and Redesign of the Tuner without Spring Fingers for the LEReC Warm Cavity

cavity, vacuum, SRF, electron

1116

B.P. Xiao, J.M. Brennan, J.C. Brutus, K. Mernick, S. Polizzo, S.K. Seberg, F. Severino, K.S. Smith, A. Zaltsman
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A folded coaxial tuner without spring fingers was designed for the Low Energy RHIC electron Cooler (LEReC) 2.1 GHz warm cavity. During RHIC run 2019, this tuner was found to cause cavity trips via different failure modes. After analyzing these failure modes, a new straight coaxial tuner without spring fingers was proposed and was installed. We show the operational experience of the new tuner in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB359

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paper received ※ 17 May 2021 paper accepted ※ 25 June 2021 issue date ※ 29 August 2021

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MOPAB363

Design, Characteristics and Dynamic Properties of Mobile Plunger-based Frequency Tuning System for Coaxial Half Wave Resonators

cavity, experiment, controls, resonance

1129

D. Bychanok, S. Huseu, S.A. Maksimenko, A.E. Sukhotski
INP BSU, Minsk, Belarus
A.V. Butenko, E. Syresin
JINR, Dubna, Moscow Region, Russia
M. Gusarova, M.V. Lalayan, S.M. Polozov
MEPhI, Moscow, Russia
V.S. Petrakovsky, A.I. Pokrovsky, A. Shvedov, S.V. Yurevich
Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
Y. Tamashevich
HZB, Berlin, Germany

The practical realization of a prototype of the frequency tuning system (FTS) for coaxial half-wave cavities (HWR) for the Nuclotron-based Ion Collider fAcility (NICA) injector is presented. The impact of FTS on electromagnetic parameters of copper HWR prototype is experimentally studied and discussed. The most important parameters like tuning range, tuning sensitivity, the dependence of the resonant frequency on the position of the plungers are estimated. The effective operation algorithms of the proposed FTS are discussed and analyzed. The dynamic characteristics of FTS are investigated and showed the ability to adjust the frequency with an accuracy of about 70 Hz.

Poster MOPAB363 [3.597 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB363

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021

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MOPAB392

Alternative RF Tuning Methods Performed on Spoke Cavities for ESS and MYRRHA Projects

cavity, target, simulation, experiment

1196

P. Duchesne, S. Blivet, G. Olivier, G. Olry, T. Pépin-Donat
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

In order to obtain the target frequency in operation, the resonant frequency of superconducting radiofrequency cavities is controlled and adjusted from the manufacturing to the end of preparation phase. Reaching this right frequency can be challenging due to the narrow frequency range defined by the tuning sensitivity of the cavity and the capability of the tuner. Mechanical deformation until plasticity is attained is of great interest to tune SRF cavities when large frequency shift is needed. But once a cavity is dressed with its helium tank, the only accessible part is its beam pipe, reducing the mechanical action to a push/pull action. This limited possibility has hence to be skilfully associated with chemical etching. An original mechanical tuning of Spoke dressed cavities consists in increasing the pressure inside the helium tank to induce a permanent deformation of the cavity walls. The frequency shift induced by nonlinear deformation is numerically evaluated in order to determine the pressure increments. Both methods were successfully performed on the cavities of the ESS accelerator and of the Myrrha project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB392

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paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 17 August 2021

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MOPAB410

Preliminary Studies of a Compact VHEE Linear Accelerator System for FLASH Radiotherapy

linac, radiation, electron, impedance

1229

L. Giuliano, F. Bosco, M. Carillo, D. De Arcangelis, L. Faillace, L. Ficcadenti, M. Migliorati, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
D. Alesini, M. Behtouei, B. Spataro
INFN/LNF, Frascati, Italy
G. Cuttone, G. Torrisi
INFN/LNS, Catania, Italy
V. Favaudon, S. Heinrich, A. Patriarca
Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France

Funding: The work is supported by La Sapienza University, research grant "grandi progetti di ricerca 2020".
The Flash Radio Therapy is a revolutionary new technique in the cancer cure: it spares healthy tissue from the damage of the ionizing radiation maintaining the tumor control as efficient as in conventional radiotherapy. To allow the implementation of the FLASH Therapy concept into actual clinical use, it is necessary to have a linear accelerator able to deliver the very high dose and very high dose rate (>10⁶ Gy/s) in a very short irradiation time (beam on time < 100ms). Low energy S-band Linacs (up to 7 MeV) are being used in Radiobiology and pre-clinic applications but in order to treat deep tumors, the energy of the electrons should achieve the range of 60-100 MeV. In this paper, we address the main issues in the design of a compact C band (5.712 GHz) electron linac-VHEE for FLASH Radio Therapy. We present preliminary studies on C-band structures at La Sapienza and at INFN-LNS, aiming to reach a high accelerating gradient and high current necessary to deliver a dose >1 Gy/pulse, with very short electron pulse.

Poster MOPAB410 [0.650 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB410

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021

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MOPAB412

Accelerator Production of Mo-99 Using Mo-100

target, radiation, electron, diagnostics

1237

J.L. McCarter, M.J. Brennan, S.M. Burns, J.T. Harvey, S.W. Kelley, T.A. Montenegro, Q. Schiller
NorthStar Medical Technologies, LLC, Beloit, USA

Funding: DE-NA0001878
Tc-99m is an essential radionuclide for nearly 40,000 diagnostic nuclear medicine tests in the U.S. each day. Its daily production depends on Mo-99, which must be replenished weekly due to Mo-99’s 2.75 day half-life. Mo-99, in the past, was supplied from uranium fission production, depending on overseas nuclear reactors that average 50 years old. Their age in combination with shipment uncertainties make the availability of Mo-99 fragile and subject to severe shortages. The U.S. now has one domestic, FDA-approved supplier that produces Mo-99, NorthStar Medical Radioisotopes. Currently, NorthStar produces Mo-99 via the irradiation of Mo-98 in a nuclear reactor. In the future, NorthStar will also irradiate Mo-100 with accelerator created x-rays to produce Mo-99. This process will use 2 distinct, 40 MeV, 125 kW average electron accelerators, Rhodotrons produced by IBA. Accelerator produced Mo-99 has several advantages over that produced by reactors, including a dual supply and an ability to adjust irradiation timing to meet radiopharmacy demands, such as Sunday delivery. NorthStar is currently installing and commissioning this accelerator based system, entering production in late-2022.

Poster MOPAB412 [2.150 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB412

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paper received ※ 24 May 2021 paper accepted ※ 07 June 2021 issue date ※ 19 August 2021

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MOPAB413

The Next Ion Medical Machine Study at CERN: Towards a Next Generation Cancer Research and Therapy Facility with Ion Beams

synchrotron, linac, proton, superconducting-magnet

1240

M. Vretenar, V. Bencini, E. Benedetto, M.R. Khalvati, A.M. Lombardi, M. Sapinski, D. Tommasini
CERN, Meyrin, Switzerland
E. Benedetto, M. Sapinski
TERA, Novara, Italy
P. Foka
GSI, Darmstadt, Germany

Cancer therapy with ions has several advantages over X-ray and proton therapy, but its diffusion remains limited primarily because of the size and cost of the accelerator. To develop technologies that might improve performance and reduce accelerator cost with respect to present facilities, CERN has recently launched the Next Ion Medical Machine Study (NIMMS), leveraging CERN expertise in accelerator fields to disseminate technologies developed for basic science. A perspective user and key partner of NIMMS is the SEEIIST (South East European International Institute for Sustainable Technologies), established to build in the region an innovative facility for combined cancer therapy and biomedical research with ion beams. For SEEIIST and other potential users, three options are being considered. Conceptual designs of a warm-magnet synchrotron at high beam intensity, of a compact superconducting synchrotron, and of a high-frequency linear accelerator have been compared in terms of cost, risk and development time. The development of curved superconducting magnets, of compact synchrotrons and ion gantries, and of linacs is being pursued within EU-funded projects or specific collaborations

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB413

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paper received ※ 18 May 2021 paper accepted ※ 20 July 2021 issue date ※ 13 August 2021

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TUXA03

Progress in Mastering Electron Clouds at the Large Hadron Collider

simulation, electron, luminosity, experiment

1273

G. Iadarola, B. Bradu, L. Mether, K. Paraschou, V. Petit, G. Rumolo, L. Sabato, G. Skripka, M. Taborelli, L.J. Tavian
CERN, Geneva, Switzerland
K. Paraschou
AUTH, Thessaloniki, Greece

During the second operational run of the Large Hadron Collider (LHC) a bunch spacing of 25 ns was used for the first time for luminosity production. With such a spacing, electron cloud effects are much more severe than with the 50-ns spacing, which had been used in the previous run. Beam-induced conditioning of the beam chambers mitigated the e-cloud formation to an extent that allowed an effective exploitation of 25 ns beams. Nevertheless, even after years of conditioning, e-cloud effects remained very visible, affecting beam stability and beam quality, and generating strong heat loads on the beam screens of the superconducting magnets with puzzling features. In preparation for the High Luminosity LHC upgrade, remarkable progress has been made in the modeling of the e-cloud formation and of its influence on beam stability, slow losses and emittance blow up, as well as in the understanding of the underlying behavior of the beam-chamber surface. In this contribution, we describe the main experimental observations from beam operation, the outcome of laboratory analysis conducted on beam screens extracted after the run, and the main advancements in the modeling of these phenomena.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA03

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 29 August 2021

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TUXA04

Coherent Excitations and Circular Attractors in Cooled Ion Bunches

electron, collider, experiment, proton

1279

S. Seletskiy, A.V. Fedotov, D. Kayran
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
In electron coolers, under certain conditions, a mismatch in either gamma-factors or trajectory angles between an electron and an ion beam can cause the formation of a circular attractor in the ion beam phase space. This leads to coherent excitations of the ions with a small synchrotron or betatron amplitude and results in unusual beam dynamics, including bifurcations. In this paper, we consider the effect of coherent excitations and discuss its implications both for Low Energy RHIC Electron Cooler (LEReC) and for high energy electron coolers proposed for the Electron-Ion Collider (EIC).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA04

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

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TUXC03

Ferro-Electric Fast Reactive Tuner Applications for SRF Cavities

cavity, SRF, beam-loading, controls

1305

N.C. Shipman, A. Castilla, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley, H. Timko
CERN, Geneva, Switzerland
I. Ben-Zvi
BNL, Upton, New York, USA
G. Burt, A. Castilla
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
C.-J. Jing, A. Kanareykin
Euclid TechLabs, Solon, Ohio, USA

A Ferro-Electric fast Reactive Tuner (FE-FRT) is a novel type of RF cavity tuner containing a low loss ferroelectric material. FE-FRTs have no moving parts and allow cavity frequencies to be changed extremely quickly (on the timescale of 100s of ns or less). They are of particular interest for SRF cavities as they can be placed outside the liquid helium environment and without an FE-FRT it’s typically very difficult to tune SRF cavities quickly. FE-FRTs can be used for a wide variety of use cases including microphonics suppression, RF switching, and transient beam loading compensation. This promises entirely new operational capabilities, increased performance and cost savings for a variety of existing and proposed accelerators. An overview of the theory and potential applications will be discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC03

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

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TUPAB060

Machine Learning on Beam Lifetime and Top-Up Efficiency

network, storage-ring, emittance, photon

1499

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

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

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

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

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TUPAB061

Anomaly Detection by Principal Component Analysis and Autoencoder Approach

network, power-supply, storage-ring, photon

1502

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

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

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

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

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TUPAB063

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

injection, controls, experiment, radiation

1508

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

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

Poster TUPAB063 [6.169 MB]

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

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

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TUPAB064

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

FEL, undulator, dipole, operational-performance

1512

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

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

Poster TUPAB064 [4.053 MB]

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

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

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TUPAB065

Solaris Storage Ring Performance After 6 Years of Operation

storage-ring, MMI, synchrotron, vacuum

1515

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

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

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

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

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TUPAB067

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

FEL, wiggler, radiation, diagnostics

1522

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

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

Poster TUPAB067 [1.023 MB]

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

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

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TUPAB074

S-Band Transverse Deflecting Structure Design for CompactLight

klystron, FEL, cavity, impedance

1540

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

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

Poster TUPAB074 [1.557 MB]

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

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

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TUPAB079

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

FEL, controls, electron, acceleration

1555

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

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

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

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

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TUPAB099

Construction of an Infrared FEL at the Compact ERL

FEL, undulator, laser, electron

1608

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

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

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

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

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TUPAB115

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

experiment, FEL, electron, undulator

1659

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

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

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

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

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TUPAB134

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

linac, booster, quadrupole, alignment

1703

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

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

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

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

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TUPAB178

Recommissioning of the CRYRING@ESR Electron Cooler

electron, experiment, target, acceleration

1816

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

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

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

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

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TUPAB187

Reconstruction of U400M Cyclotron: Upgrade of U400M Cyclotron Magnetic Structure

cyclotron, extraction, MMI, ECR

1838

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

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

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

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

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TUPAB193

Operation and Maintenance of Chinese Spallation Neutron Source Stripper Foil

injection, neutron, radiation, site

1858

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

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

Poster TUPAB193 [0.395 MB]

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

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

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TUPAB201

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

acceleration, vacuum, electron, controls

1884

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

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

DOI •

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

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

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TUPAB203

Electromagnetic Simulations of a Novel Proton Linac Using VSim on HPC

linac, rfq, simulation, controls

1887

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

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

DOI •

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

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

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TUPAB213

Important Drift Space Contributions to Non-Linear Beam Dynamics

resonance, sextupole, lattice, storage-ring

1914

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

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

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

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

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TUPAB214

Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis

synchrotron, storage-ring, lattice, closed-orbit

1917

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

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

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

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

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TUPAB215

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

quadrupole, network, lattice, focusing

1920

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

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

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

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

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TUPAB217

Effect of Undulators on Transverse Resonant Island Orbits

undulator, diagnostics, dipole, optics

1927

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

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

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

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

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TUPAB222

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

experiment, storage-ring, electron, synchrotron

1942

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

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

Poster TUPAB222 [1.713 MB]

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

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

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TUPAB270

Thermal Transition Design and Beam Heat-load Estimation for the COLDDIAG Refurbishment

vacuum, cryogenics, diagnostics, simulation

2097

H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The COLDDIAG (cold vacuum chamber for beam heat load diagnostics) developed at Karlsruhe Institute of Technology has been modified for more studies at cryogenic temperatures different from the previous operations at 4 K in a cold bore and at 50 K in a thermal shield. The key components in this campaign are two thermal transitions connecting both ends of the bore at 50 K with the shield at the same or higher temperature. In this paper, we present design efforts for the compact transitions, allowed heat intakes to the cooling power margin and mechanical robustness in the cryogenic environment. A manufacture scheme for the transition and its peripheral is also given. In addition, the beam heat loads in the refurbished COLDDIAG are estimated in terms of the accelerator beam parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB270

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paper received ※ 12 May 2021 paper accepted ※ 02 June 2021 issue date ※ 12 August 2021

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TUPAB282

Optical Beam Loss Monitor Based on Fibres for Beam Loss Monitoring and RF Breakdown Detection

diagnostics, synchrotron, experiment, machine-protect

2136

N. Kumar, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from STFC under grant reference ST/V001302/1.
Standard beam loss monitors are used to detect losses at specific locations which is not a practical solution for loss monitoring throughout the whole beam-line. Optical fibre beam loss monitors (oBLMs) are based on the detection of Cherenkov radiation from high energy charged particles having the advantage of covering more than 100 m of an accelerator with a single detector. This system was successfully installed at the Australian Synchrotron covering the entire facility for beam loss measurements. Successful measurements were also demonstrated on the Compact Linear Accelerator for Research and Applications (CLARA), UK with sub-metre beam loss resolution. oBLMs are non-invasive monitors for the detection of the beam loss and RF breakdown within particle accelerators, which has been developed by the QUASAR Group based at the Cockcroft Institute/University of Liverpool, UK in collaboration of D-Beam Ltd, UK. This paper discusses the overview of the system, the incorporation of the monitor into the accelerator diagnostic system, calibration experiment of oBLM and future plans for the system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB282

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 10 August 2021

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TUPAB286

Experience with On-line Optimizers for APS Linac Front End Optimization

linac, gun, controls, injection

2151

H. Shang, M. Borland, X. Huang, Y. Sun
ANL, Lemont, Illinois, USA
M. Song, Z. Zhang
SLAC, Menlo Park, California, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 and BES R&D project FWP 2020-ANL-34573
While the APS linac lattice is set up using a model developed with ELEGANT, the thermionic RF gun front end beam dynamics has been difficult to model. One of the issues is that beam properties from the thermionic gun can vary from time to time. As a result, linac front end beam tuning is required to establish good matching and maximize the charge transported through the linac. We have been using a traditional simplex optimizer to find the best settings for the gun front end magnets and steering magnets. However, it takes a long time and requires some fair initial conditions. Therefore, we imported other on-line optimizers, such as robust conjugate direction search (RCDS) which is a classic optimizer as simplex, multi-objective particle swarm (MOPSO), and multi-generation gaussian process optimizer (MG-GPO) which is based on machine learning technique. In this paper we report our experience with these on-line optimizers for maximum bunch charge transportation efficiency through the linac.

Poster TUPAB286 [2.964 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB286

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paper received ※ 12 May 2021 paper accepted ※ 08 July 2021 issue date ※ 29 August 2021

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TUPAB287

Application of Artificial Neural Network in the APS Linac Bunch Charge Transmission Efficiency

linac, kicker, controls, photon

2155

H. Shang, R. Maulik, Y. Sun
ANL, Lemont, Illinois, USA
T. Xu
Northern Illinois University, DeKalb, Illinois, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In recent years there has been a rapid growth in machine learning (ML) and artificial intelligence (AI) applications in accelerators. As the scale of complexity and sophistication of modern accelerators grows, the difficulties in modeling the machine increase greatly in order to include all the interacting subsystems and to consider the limitation of various diagnostics to benchmark against measurements. Tools based on ML can help substantially in revealing correlations of machine condition and beam parameters that are not easily discovered using traditional physics model-based simulations, reducing machine tuning up time etc among the many possible applications. While at APS we have many excellent tools for the optimization, diagnostics, and controls of the accelerators, we do not yet have ML-based tools established. It is our desire to test ML in our machine operation, optimization, and controls. In this paper, we introduce the application of neural networks to the APS linac bunch charge transmission efficiency.

Poster TUPAB287 [0.781 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB287

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paper received ※ 12 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021

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TUPAB289

Towards Hysteresis Aware Bayesian Regression and Optimization

ISAC, experiment, target, controls

2159

R.J. Roussel
University of Chicago, Chicago, Illinois, USA
A. Hanuka
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. National Science Foundation under Award No. PHY-1549132, the Center for Bright Beams.
Algorithms used today for accelerator optimization assume a simple proportional relationship between an intermediate tuning parameter and the resultant field or mechanism which influences the beam. This neglects the effects of hysteresis, where the magnetic or mechanical response depends not only on the current parameter value, but also on the historical parameter values. This prevents the use of one to one surrogate models, such as Gaussian processes, to assist in optimization when hysteresis effects are not negligible, since identical points in input space no longer correspond to a same point in output space. In this work, we demonstrate how Bayesian inference can be used in conjunction with Gaussian processes to jointly model both the hysteresis cycle of magnetic elements and the beam response. Using this technique we demonstrate how to model the hysteresis cycle of a magnet during accelerator operation in situ by only measuring the beam response, without direct magnetic field measurements. This allows us to quickly build accurate statistical models of the beam response that can be used for rapid tuning of accelerators where hysteresis effects are dominant.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB289

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

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TUPAB298

First Steps Toward an Autonomous Accelerator, a Common Project Between DESY and KIT

electron, laser, controls, simulation

2182

A. Eichler, F. Burkart, J. Kaiser, W. Kuropka, O. Stein
DESY, Hamburg, Germany
E. Bründermann, A. Santamaria Garcia, C. Xu
KIT, Karlsruhe, Germany

Funding: Helmholtz Artificial Cooperation Unit
Reinforcement Learning algorithms have risen in popularity in recent years in the accelerator physics community, showing potential in beam control and in the optimization and automation of tasks in accelerator operation. The Helmholtz AI project "Machine Learning toward Autonomous Accelerators" is a collaboration between DESY and KIT that works on investigating and developing RL applications for the automatic start-up of electron linear accelerators. The work is carried out in parallel at two similar research accelerators: ARES at DESY and FLUTE at KIT, giving the unique opportunity of transfer learning between facilities. One of the first steps of this project is the establishment of a common interface between the simulations and the machine, in order to test and apply various optimization approaches interchangeably between the two accelerators. In this paper we present the first results on the common interface and its application to beam focusing in ARES, and the idea of laser shaping with spatial light modulators at FLUTE.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB298

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 17 August 2021

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TUPAB314

SPS Personnel Protection System: From Design to Commissioning

site, controls, MMI, PLC

2224

T. Ladzinski, T. Hakulinen, F. Havart, V. Martins De Sousa Dos Rios, M. Munoz Codoceo, P. Ninin, J.P. Ridewood, E. Sanchez-Corral Mena, D. Vaxelaire
CERN, Meyrin, Switzerland

During the second long shutdown (LS2) of the accelerator complex at CERN, the access system of the Super Proton Synchrotron (SPS) was completely renovated. This complex project was motivated by the technical obsolescence and lack of sufficient redundancy in the existing system, as well as by the need for homogenisation of technologies and practices across the different machines at CERN. The new Personnel Protection System includes 16 state-of-the-art access points making sure that only fully identified, trained and authorised personnel can enter the facility and an interlock system with a rationalized number of safety chains designed to meet the current safety standards. The control part is based on Siemens 1500 series of programmable logic controllers, complemented by a technologically diverse relay logic loop for the critical safety functions. This paper presents the new system and the design choices made to permit fast installation in a period where the access system itself was heavily used to allow vast upgrades of the SPS accelerator and its infrastructure. It also covers the verification and validation methodology and lessons learned during the commissioning phase.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB314

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paper received ※ 14 May 2021 paper accepted ※ 10 June 2021 issue date ※ 22 August 2021

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TUPAB315

Development of Disaster Prevention System for Accelerator Tunnel

radiation, network, neutron, real-time

2228

K. Ishii, K. Bessho, M. Yoshioka
KEK, Ibaraki, Japan
Y. Kawabata, H. Matsuda, K. Matsumoto
Tobishima Corp., Tokyo, Japan
S. Tagashira
Kansai University, Osaka, Japan
N. Yamamoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Health Labor Sciences Research Grant of Japan
In an enclosed space such as a particle accelerator tunnel, ensuring worker safety during a disaster is an issue of critical importance. It is necessary to have a system in which the manager can know from outside the tunnel whether there is any worker left behind and whether the worker is escaping in the right direction. Because a global positioning system (GPS) is not available in the tunnel, we are developing a disaster prevention system that uses Wi-Fi to transmit the positioning of workers and two-way communication. The Wi-Fi access point (AP) installed in the tunnel should be radiation resistant. Additionally, the equipment carried by the worker is convenient and easy to carry. We tested the radiation hardness of commercial AP devices and developed a smartphone application to perform location information transmission and simultaneous character transmission. In 2019, we installed the system on the J-PARC Main Ring and started its operation. In this paper, the functions of the developed system and its prospects are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB315

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 25 August 2021

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TUPAB316

New Operational Quantities for Radiation Protection by ICRU and ICRP: Impact on Workplaces at Accelerators

radiation, photon, MMI, target

2231

Th. Otto, M. Widorski
CERN, Meyrin, Switzerland

In radiation protection, Effective Dose E quantifies stochastic radiation detriment. E is defined as a weighted sum of absorbed dose to organs and tissues and cannot be measured directly. ICRU has defined operational quantities to measure effective dose approximately, such as Ambient dose equivalent H*(10). At high energies, the estimates provided by H*(10) deviate strongly from effective dose. In 2020, ICRU and ICRP have recommended new operational quantities for external radiation with a definition close to the one of effective dose, and published an extensive collection of conversion coefficients from particle fluence to the new quantities (1). Ambient dose H* serves for operational monitoring purposes. The new definition alleviates the observed discrepancies of H*(10) with effective dose. In this paper, we present a numerical study of effective dose E, ambient dose equivalent H*(10) and ambient dose H* in radiation fields at workplaces at proton- and electron accelerators. These places include locations behind primary shielding, in access mazes and in the vicinity of activated accelerator components.
(1) ICRU Report 95, Operational quantities for external radiation

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB316

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paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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TUPAB325

Data-Driven Risk Matrices for CERN’s Accelerators

proton, linac, synchrotron, machine-protect

2260

T. Cartier-Michaud, A. Apollonio, G.B. Blarasin, B. Todd, J.A. Uythoven
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
A risk matrix is a common tool used in risk assessment, defining risk levels with respect to the severity and probability of the occurrence of an undesired event. Risk levels can then be used for different purposes, e.g. defining subsystem reliability or personnel safety requirements. Over the history of the Large Hadron Collider (LHC), several risk matrices have been defined to guide system design. Initially, these were focused on machine protection systems, more recently these have also been used to prioritize consolidation activities. A new data-driven development of risk matrices for CERN’s accelerators is presented in this paper, based on data collected in the CERN Accelerator Fault Tracker (AFT). The data-driven approach improves the granularity of the assessment, and limits uncertainty in the risk estimation, as it is based on operational experience. In this paper the authors introduce the mathematical framework, based on operational failure data, and present the resulting risk matrix for LHC.

Poster TUPAB325 [0.499 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB325

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 17 August 2021

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TUPAB329

Pattern Based Parameter Setup of the SNS Linac

cavity, linac, DTL, beam-losses

2276

C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA
A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy.
Theoretical and practical aspects of beam tuning procedures used for the SNS linac are discussed. The SNS linac includes two sections of beam acceleration. Acceleration in the first section up to 185.5 MeV is done with a room temperature copper linac which consists of both Drift Tube Linac (DTL) and Coupled Cavity Linac (CCL) Radio Frequency (RF) cavities. The second section consists of 81 Superconducting RF (SRF) cavities which accelerate the beam to the final beam energy of 1 GeV. The linac is currently capable of delivering an average beam power output of 1.44 MW with typical yearly operating hours of around 4500 hours. Due to the high power output and high availability of the linac, activation of accelerator equipment is a significant concern. The linac tuning process consists of three stages: model based setup of amplitudes and phases of the RF cavities, empirical beam loss reduction, and then documentation of the final amplitudes and phases of RF cavities after the empirical tuning. The final step is needed to ensure fast recovery from an SRF cavity failure. This paper discusses models, algorithms, diagnostic tools, software, and practices that are used for these stages.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB329

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paper received ※ 22 May 2021 paper accepted ※ 28 May 2021 issue date ※ 25 August 2021

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TUPAB343

Final Design Studies for the VSR DEMO 1.5 GHz Coupler

multipactoring, SRF, cavity, electron

2300

E. Sharples-Milne, V. Dürr, P. Echevarria, J. Knobloch, A. Neumann, A.V. Vélez
HZB, Berlin, Germany

With the 1.5 GHz couplers for the Variable pulse length Storage Ring (VSR) DEMO now in the manufacturing stages, the studies that led to the final coupler design will be presented. The system specific constraints and design modifications that combat the challenges of thermomechanical stresses, higher order mode (HOM) propagation and dimensional constraints are explored. This includes S-Parameter analysis, an in-depth study of the coupling factor, and multipacting studies for the average (1.5 kW) and peak (16 kW) power.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB343

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 14 August 2021

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TUPAB345

Availability Modeling of the Solid-State Power Amplifiers for the CERN SPS RF Upgrade

cavity, simulation, MMI, SRF

2308

L. Felsberger, A. Apollonio, T. Cartier-Michaud, E. Montesinos, J.C. Oliveira, J.A. Uythoven
CERN, Geneva, Switzerland

Funding: This project has received funding from the Euratom research and training programme 2019-2020 under grant agreement No 945077.
As part of the LHC Injector Upgrade program a complete overhaul of the Super Proton Synchrotron Radio-Frequency (RF) system took place. New cavities have been installed for which the solid-state technology was chosen to deliver a combined RF power of 2 MW from 2560 RF amplifiers. This strategy promises high availability as the system continues operation when some of the amplifiers fail. This study quantifies the operational availability that can be achieved with this new installation. The evaluation is based on a Monte Carlo simulation of the system using the novel AvailSim4 simulation software. A model based on lifetime estimations of the RF modules is compared against data from early operational experience. Sensitivity analyses have been made, that give insight to the chosen operational scenario. With the increasing use of solid-state RF power amplifiers, the findings of this study provide a useful reference for future application of this technology in particle accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB345

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 19 August 2021

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TUPAB351

The Progress of 300 kW Home-Made Fully Solid-State Transmitter for TPS

controls, power-supply, ISOL, HOM

2328

T.-C. Yu, F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

To support the stable operation of Taiwan Photon Source (TPS) with 500mA beam current and the in-creasing beam line construction, a 3rd RF plant is thus constructed for such demand. The RF power source of the other 2 RF plants adopts klystron type transmitter and the 3rd RF plants is transferred to new technology of solid-state for better redundancy and easier mainte-nance. Base on the success of solid-state power ampli-fier development in 2020, a 3rd RF power source is thus decided to be made in house by solid-state tech-nology. The 500MHz 300kW solid-state transmitter is constructed by 4 80 kW solid-state power amplifier (SSPA) towers and power combined by 3 WR1800 3-dB hybrid couplers. Each tower is consisted of 110 850W final stage SSPA modules with 4 100W pre-amplifiers and 6 600W drive amplifiers. The pre and drive amplifiers are power combined for higher redun-dancy. The DC power are economical industrial 48V AC-DC rack mount power supplies which are parallel connected for higher total DC power and best redun-dancy. The architecture and present progress are pre-sented in this article.

Poster TUPAB351 [2.348 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB351

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

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TUPAB358

Novel 500 MHz Solid State Power Amplifier Module Development at Sirius

cavity, impedance, synchrotron, storage-ring

2349

M.H. Wallner, R.H. Farias, A.P.B. Lima, F. Santiago de Oliveira
LNLS, Campinas, Brazil

A new solid state power amplifier (SSPA) module is being developed at the Brazilian Center for Research in Energy and Materials (CNPEM) to drive one of the superconducting RF cavities to be installed at Sirius, its new 3 GeV fourth generation synchrotron light source. Several prototypes have been built and tested in-house, and a planar balun was designed to achieve a push-pull configuration at deep class AB operation. Efforts to optimize heat exchange in various ways have been made. Results obtained thus far are presented and the next steps concerning development are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB358

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

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TUPAB362

Physical Design of Electrostatic Deflector in CSNS Muon Source

simulation, positron, high-voltage, emittance

2360

Y.W. Wu, S. Li, J.Y. Tang, X. Wu
IHEP, Beijing, People’s Republic of China
C.D. Deng, Y. Hong
DNSC, Dongguan, People’s Republic of China
Y.Q. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

CSNS will build a muon source at the end of the RTBT. In the current design, the muon source propose two schemes, namely the baseline scheme and the baby scheme. High voltage electrostatic deflectors (ESD) are used to deflect the beam in the two schemes. A three-channel ESD with 400 kV HV is employed in the baseline scheme and a 210 kV dual-channel ESD in the simplified scheme. According to physical requirements, the electric field concentration factor is introduced, and the electrode of ESD is theoretically designed. 2D and 3D simulations are carried out to analyze the characteristics of electric field distribution by OPERA. The geometry of the electrodes also met the requirements of electric field uniformity, high voltage resistance and mechanical strength at the same time. In the baseline scheme and the baby scheme, the ESD electric field concentration factors are 1.36 and 1.53, and the maximum electric field is 6.78MV/m and 4.6MV/m, respectively. The design meets the requirements and is reasonably feasible.

Poster TUPAB362 [2.214 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB362

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paper received ※ 13 May 2021 paper accepted ※ 09 June 2021 issue date ※ 22 August 2021

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TUPAB375

Commissioning and Operation of Superconducting Multipole Wiggler at Siam Photon Source

photon, MMI, wiggler, electron

2398

P. Sunwong, S. Boonsuya, S. Chaichuay, T. Chanwattana, Ch. Dhammatong, A. Kwankasem, C.P. Preecha, T. Pulampong, K. Sittisard, V. Sooksrimuang, S. Srichan, P. Sudmuang, N. Suradet, S. Tancharakorn
SLRI, Nakhon Ratchasima, Thailand

A new insertion device, Superconducting Multipole Wiggler (SMPW) with the peak field strength of 3.5 T, was installed in the storage ring of Siam Photon Source as a radiation source for a new hard X-ray beamline. Cool-down process, as well as magnet training, was performed with careful tuning of liquid helium filling procedure for efficient management of liquid helium supply. The filling procedure was also optimized for safe operation of the magnet. The SMPW commission-ing was successfully carried out with electron beam and the effect of SMPW on electron beam dynamics was observed. It can be minimized using quadrupole magnets and horizontal/vertical correctors.

Poster TUPAB375 [1.160 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB375

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 31 August 2021

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TUPAB378

Superconducting Dipole Magnets for the SIS100 Synchrotron

dipole, synchrotron, multipole, simulation

2401

F. Kaether, P. Aguar Bartolome, A. Bleile, G. Golluccio, J. Ketter, P. Kosek, F. Kurian, V. Marusov, J.P. Meier, S.S. Mohite, C. Roux, P.J. Spiller, K. Sugita, A. Szwangruber, P.B. Szwangruber, A. Warth, H.G. Weiss
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR) is currently under construction at GSI Darmstadt, Germany. For its main accelarator, the SIS100 synchrotron, 110 superconducting dipole magnets has been produced and extensively tested. The fast-ramped Nuclotron-type superferric dipoles were manufactured with high effort regarding a precise magnetic field which could be proven by magnetic field measurements with high accuracy. Stable operation conditions at 4.5 K were achieved including an excellent quench behaviour and precise geometrical and electrical properties. An overview on design, production, operation, tests and measurement results will be given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB378

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

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TUPAB380

Testing of the First of Series Quadrupole Doublet Module for the SIS100 Synchrotron

quadrupole, synchrotron, superconducting-magnet, cryogenics

2409

P. Aguar Bartolome, M. Al Ghanem, M. Becker, A. Bleile, R. Bluemel, L.H.J. Bozyk, V.I. Datskov, W. Freisleben, A. Kario, P. Kowina, K.K. Kozlowski, F. Kurian, S. Lindner, J.P. Meier, T. Miertsch, S.S. Mohite, V.P. Plyusnin, I. Pongrac, C. Roux, C. Schroeder, P.J. Spiller, K. Sugita, A. Szwangruber, P.B. Szwangruber, F. Walter, H. Welker, St. Wilfert, T. Winkler, S. Zeller
GSI, Darmstadt, Germany

A new international facility for antiproton and ion research (FAIR) is currently under construction in Darmstadt, Germany. The high intensity primary beam required for different research experiments will be provided by the SIS100 heavy ion synchrotron. The synchrotron is composed of fast cycling superconducting magnets from which about 300 will be integrated in Quadrupole Doublet Modules (QDM). Each module consists of two units composed of a quadrupole and corrector magnets. The First of Series Quadrupole Doublet Module was delivered to the test facility at GSI in November 2019. The assembled doublet was subjected to a dedicated test program to verify the functionality of the module components at cryogenic temperature and operating conditions. The results obtained during the testing campaign will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB380

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

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TUPAB389

High Precision Four Quadrant Converter with GaN Technology

controls, simulation, power-supply, damping

2431

M. Incurvati, T. Margreiter, R. Stärz
MCI, Innsbruck, Austria
T. Riedler
NTUT, Taipei City, Taiwan

New proton therapy facilities for the cure of tumors as well as high-energy photon sources are currently being installed all around the world. In this field, the request for special power supplies for corrector, scanning, and quadrupole magnets are increasing. For these applications, mandatory requirements are high bandwidth and current stability as well as low output ripple which are conflicting constraints. A feasibility study, prototype development, measurements, and investigations on the control methodology of a wide-bandgap GaN semiconductor-based power module is presented in the paper. The developed power module features the following characteristics: Eurocard standard PCB, bipolar 4Q operation, minimum switching frequency 100 kHz, bandwidth 5 kHz, output voltage and current up to 200 V / 8 A, output current ripple <20 ppm. The enlisted characteristics make it suitable for high inductive loads requiring fast transients (scanning magnets). An RST controller will be developed and a system identification approach to the transfer function of two parallel-connected power modules will be presented along with simulations assessing the performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB389

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paper received ※ 19 May 2021 paper accepted ※ 25 June 2021 issue date ※ 21 August 2021

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TUPAB393

Study of Remote Helium Mass Spectrometer Leak Detection in Accelerator

vacuum, gun, detector, controls

2441

H.Y. He, D.H. Zhu
IHEP CSNS, Guangdong Province, People’s Republic of China
J.M. Liu
DNSC, Dongguan, People’s Republic of China

In order to solve the problem that the vacuum system of the accelerator can’t be close to the operation for a long time, a long-distance helium mass spectrometer leak detection system is explored by studying the structure of the conventional round tube vacuum box of the vacuum system, which integrates the online vacuum leak detection, defect diagnosis and process design, improves the digital operation, realizes the accurate and effective detection of the leak location range and leak rate, and provides the technology for the remote leak detection of the vacuum system. Support.

Poster TUPAB393 [0.666 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB393

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paper received ※ 13 May 2021 paper accepted ※ 31 May 2021 issue date ※ 10 August 2021

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TUPAB398

Vacuum Issues with Argon Gas in the LANSCE Accelerator

vacuum, neutron, linac, monitoring

2450

T. Tajima, J.E. Bernal, D.A. Byers, J.P. Chamberlin, P. Pizzol, A. Poudel, K.A. Stephens
LANL, Los Alamos, New Mexico, USA

Funding: US DOE NNSA
In the Los Alamos Neutron Science Center (LANSCE) accelerator, there are about 220 500-L/s ion pumps running all the time. The oldest pumps recorded in the current system were installed in 1983. All the ion pumps are diode type ion pumps. In 2017, we started to suffer from ion pumps trips in an accelerator module 15 (M15) that includes 3 500-L/s ion pumps and they caused beam down times of the accelerator during the production run cycles. This paper reports the details of these trips, how we found it was argon gas that was causing the trips and how we tried to reduce it.

Poster TUPAB398 [0.817 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB398

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paper received ※ 19 May 2021 paper accepted ※ 01 June 2021 issue date ※ 28 August 2021

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TUPAB401

Mechanical Design, Fabrication and Characterization of Electron Beam Position Monitors for Sirius

pick-up, vacuum, impedance, storage-ring

2461

R. Defavari, O.R. Bagnato, M.W.A. Feitosa, F.R. Francisco, G.R. Gomes, D.Y. Kakizaki, R.L. Parise, R.D. Ribeiro
LNLS, Campinas, Brazil

Beam Position Monitors were designed and manufactured to meet Sirius operation requirements. Final dimensional accuracy and stability of the BPM were achieved by careful specification of its components’ manufacturing tolerances and materials. AISI-305 Stainless Steel was used for the BPM support fabrication due to magnetic and thermal expansion constraints. High purity molybdenum for the electrode pin and Ti6Al4V F136 G23 alloy for housing was used to manufacture the sensor components for their thermal characteristics. The electrical insulator was made of high alumina. The materials were joined by an active metal brazing process using 0,01mm accurate fixtures. The brazed sensors were subjected to dimensional, mechanical, and metallurgical testing, as well as leak detection and optical microscopy inspection at each stage. The sensors were joined in Ti6Al4V F136 BPM bodies using TIG welding. Dimensional sorting was used to choose groups of sensors-to-body, and body-to-support pairs during the final assembly. 160 BPMs are currently in operation on Sirius storage ring. In this contribution, we present the results of BPM manufacturing and testing processes developed for Sirius.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB401

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 29 August 2021

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WEXA02

Operational Electron Cooling in the Relativistic Heavy Ion Collider

electron, collider, cathode, cavity

2516

A.V. Fedotov, K.A. Drees, W. Fischer, X. Gu, D. Kayran, J. Kewisch, C. Liu, K. Mernick, M.G. Minty, V. Schoefer, H. Zhao
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Since the invention of the electron cooling technique its application to cool hadron beams in colliders was considered for numerous accelerator physics projects worldwide. However, achieving the required high-brightness electron beams of required quality and cooling of ion beams in collisions was deemed to be challenging. An electron cooling of ion beams employing a high-energy approach with RF-accelerated electron bunches was recently successfully implemented at BNL. It was used to cool ion beams in both collider rings with ion beams in collision. Electron cooling in RHIC became fully operational during the 2020 physics run and led to substantial improvements in luminosity. This presentation will discuss implementation, optimization and challenges of electron cooling for colliding ion beams in RHIC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA02

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 31 August 2021

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WEXA05

Solving for Collider Beam Profiles from Luminosity Jitter with Ghost Imaging

luminosity, collider, GUI, diagnostics

2524

D.F. Ratner, A. Chao
SLAC, Menlo Park, California, USA

Large accelerator facilities must balance the need to achieve user performance requirements while also maximizing delivery time. At the same time, accelerators have advanced data-acquisition systems that acquire synchronous data at high-rate from a large variety of diagnostics. Here we discuss the application of ghost-imaging (GI) to measure beam parameters, switching the emphasis from beam control to data collection: rather than intentionally manipulating the accelerator, we instead passively monitor jitter gathered over thousands to millions of events to reconstruct the target of interest. Passive monitoring during routine operation builds large data sets that can even deliver higher resolution than brief periodic scans, and can provide experiments with event-by-event information. In this presentation we briefly present applications of GI to light-sources, and then discuss a potential new application for colliders: measuring the transverse beam shapes at a collider’s interaction point to determine both the integrated luminosity and the spatial distribution of collision vertices.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA05

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

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WEXA06

Study of Pb-Pb and Pb-p Collision Debris in the CERN LHC in View of HL-LHC Operation

proton, luminosity, hadron, heavy-ion

2528

M. Sabaté-Gilarte, R. Bruce, F. Cerutti, A. Lechner
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
For the first time, a full characterization of the Pb-Pb and Pb-p collision debris as well as its impact in terms of energy deposition in the long straight section (LSS) of CERN’s Large Hadron Collider has been carried out. By means of Monte Carlo simulations with FLUKA, both inelastic nuclear interaction and electromagnetic dissociation were taken into account as source term for lead ion operation, while for Pb-p operation only nuclear interaction is of importance. The radiation exposure of detectors exclusively destined for ion beam runs is assessed, allowing drawing implications of their use. This work gave the opportunity for an unprecedented validation of simulation results against measurement of beam loss monitors (BLM) in the experimental LSS during ion operation. Pb-Pb operation refers to the 2018 ion run at 6.37 TeV per charge with a +160 microrad half crossing angle in the vertical plane at the ATLAS interaction point. Instead, Pb-p operation was benchmarked for the 2016 ion run at 6.5 TeV per charge with -140 microrad half crossing angle in the vertical plane at the same location.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA06

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paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

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WEXB08

Beam Losses and Emittance Growth Studies at the Record High Space-Charge in the Booster

booster, emittance, space-charge, proton

2552

V.D. Shiltsev, J.S. Eldred, V.A. Lebedev, K. Seiya
Fermilab, Batavia, Illinois, USA

Comprehensive studies of high intensity proton beams in the 0.4-8 GeV FNAL Booster synchrotron have revealed interesting nonlinear dynamics of the beam losses and emittance growth at the record high dQ_SC=0.6. We report the results of the studies and directions of further improvements to prepare the Booster to the era of even higher intensity operation with new 0.8 GeV PIP-II linac.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB08

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paper received ※ 24 May 2021 paper accepted ※ 02 July 2021 issue date ※ 17 August 2021

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WEXC03

Review of Superconducting Radio Frequency Gun

cathode, gun, SRF, cavity

2556

R. Xiang
HZDR, Dresden, Germany

The success of proposed high power free-electron lasers (FELs) and energy recovery linac (ERL) largely depends on the development of the electron source, which requires the best beam quality and CW operation. An elegant way to realize this average brilliance is to combine the high beam quality of mature normal conducting radio frequency photoinjector with the quick developing superconducting radio frequency technology, to build superconducting rf photoinjectors (SRF guns). In last decade, several SRF gun programs based on different approaches have achieved promising progress, even succeeded in routine operation at BNL and HZDR [*,**]. In the near future SRF guns are expected to play an important role for hard X-ray FEL facilities. In this contribution, we will review the design concepts, parameters, and the status of the major SRF gun projects.
*I. Petrushina et al., Phys. Rev. Lett. 124, 244801
**J. Teichert at al., Phys. Rev. Accel. Beams 24, 033401

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC03

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paper received ※ 19 May 2021 paper accepted ※ 28 June 2021 issue date ※ 23 August 2021

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WEPAB019

RF Harmonic Kicker R&D Demonstration and Its Application to the RCS Injection of the EIC

kicker, injection, cavity, electron

2632

G.-T. Park, M.W. Bruker, J.M. Grames, J. Guo, R.A. Rimmer, S.O. Solomon, H. Wang
JLab, Newport News, Virginia, USA

The Rapid Cycling Synchrotron (RCS) of the Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL) * is an accelerating component of the electron injection complex, which provides polarized electrons in electron-ion collisions in the main Electron Storage Ring (ESR). We present the injection scheme into the RCS based on an ultra-fast harmonic kicker, whose "five odd-harmonic modes" prototype was developed in the context of the Jefferson Lab EIC (JLEIC) conceptual design **. In its early stage of R&D, the sharp (~3 ns width) waveform construction, beam dynamics, and pulsed power operation with short ramping time (~10 us) will be discussed together with the fabrication work of the JLEIC prototype ***.
* BNL, "Electron Ion Collider Conceptual Design Report", 2020
** G. Park et. al, JLAB-TN-044
*** G. Park et. al., JLAB-TN-046

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB019

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paper received ※ 17 May 2021 paper accepted ※ 22 June 2021 issue date ※ 11 August 2021

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WEPAB023

Crystal Collimation of 20 MJ Heavy-Ion Beams at the HL-LHC

collimation, hadron, collider, luminosity

2644

M. D’Andrea, R. Bruce, M. Di Castro, I. Lamas Garcia, A. Masi, D. Mirarchi, S. Redaelli, R. Rossi, B. Salvachua, W. Scandale
CERN, Geneva, Switzerland
F. Galluccio
INFN-Napoli, Napoli, Italy
L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom

The concept of crystal collimation at the Large Hadron Collider (LHC) relies on the use of bent crystals that can deflect halo particles by a much larger angle than the standard multi-stage collimation system. Following an extensive campaign of studies and performance validations, a number of crystal collimation tests with Pb ion beams were performed in 2018 at energies up to 6.37 Z TeV. This paper describes the procedure and outcomes of these tests, the most important of which being the demonstration of the capability of crystal collimation to improve the cleaning efficiency of the machine. These results led to the inclusion of crystal collimation into the LHC baseline for operation with ion beams in Run 3 as well as for the HL-LHC era. A first set of operational settings was defined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB023

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

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WEPAB039

Construction of a Compact Electron Injector Using a Gridded RF Thermionic Gun and a C-Band Accelerator

linac, electron, injection, emittance

2687

T. Inagaki, T. Asaka, T. Hara, T. Hiraiwa, N. Hosoda, E. Iwai, C. Kondo, H. Maesaka, T. Ohshima, H. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan
H. Dewa, T. Magome, Y. Minagawa, T. Sakurai
JASRI/SPring-8, Hyogo-ken, Japan
T. Fukui
RIKEN SPring-8 Center, Innovative Light Sources Division, Hyogo, Japan
S. Hashimoto
LASTI, Hyogo, Japan
S.I. Inoue, K. Kajimoto, S. Nakata, T. Seno, H. Sumitomo, R. Takesako, S. Tanaka, R. Yamamoto, M. Yoshioka
SES, Hyogo-pref., Japan
K. Yanagida
JASRI, Hyogo, Japan

A compact and low-cost 1 GeV injector linac was designed and constructed to provide injection beams to the soft X-ray synchrotron radiation facility NewSUBARU instead of the SPring-8 injector system, which will be shutdown. The total length of the injector linac needs to be less than 70 m to fit into the existing tunnel. To this end, an RF electron gun with a gridded thermionic cathode directly attached to a 238 MHz RF cavity was developed and adopted. The 500 keV, 0.6 ns, 1 nC beam emitted from the cavity is compressed to 3 ps by velocity bunching driven by a 476 MHz RF cavity and a S-band RF structure. The short-pulsed beams are accelerated up to 1 GeV with 16 C-band RF structures. In the C-band accelerator section, the klystron output of 50 MW is multiplied 4 times by a pulse compressor and fed to the 4 RF structures to generate a high accelerating field of 31 MV/m. A low-level RF system consisting of a MTCA.4 based high-speed digitizers and RF frontend boards has been constructed. This injector system is used at the 3 GeV SR facility currently under construction in Sendai. In this paper, we report the design outline and the operational performance of the injector system.

Poster WEPAB039 [2.419 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB039

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 24 August 2021

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WEPAB041

Testing of the Milliampere Booster Prototype Cavity

cavity, linac, vacuum, solenoid

2693

R.G. Heine
KPH, Mainz, Germany

The Milliampere Booster (MAMBO) is the injector linac for the Mainz Energy-recovering Superconducting Accelerator MESA. MESA is a multi-turn energy recovery linac with beam energies in the 100 MeV regime currently designed and built at Institut für Kernphysik (KPH) of Johannes Gutenberg-Universität Mainz. The main accelerator consists of two superconducting Rossendorf type modules, while the injector MAMBO relies on normal conducting technolgy. The MAMBO RF cavities are bi-periodic pi/2 structures with 33 cells and 37 cells, respectively. In this paper we present the results of the commissioning and testing of a 13 cell prototype structure.

Poster WEPAB041 [2.824 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB041

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paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 21 August 2021

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WEPAB045

European XFEL High-Power RF System - the First 4 Years of Operation

klystron, FEL, GUI, electron

2708

M. Bousonville, S. Choroba, T. Grevsmühl, S. Göller, A. Hauberg, V.V. Katalev, K. Machau, V. Vogel, B. Yildirim
DESY, Hamburg, Germany

In 2016, the installation of the European XFEL was completed and its 26 RF stations started operation in 2017. Each RF station consists of a 10 MW-1.3 GHz-multibeam klystron, a HV pulse modulator and a waveguide system to supply the superconducting cavities and the normal-conducting electron gun with RF power. During commissioning and subsequent operation, the RF stations were closely monitored and causes of failures were investigated. For the optimisation of the RF systems, the various RF station failures were evaluated according to their impact on accelerator operation and the measures to eliminate them were prioritised accordingly. This report describes the operation experience and improvements of the high-power RF stations during the first 4 years of operation.

Poster WEPAB045 [6.887 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB045

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paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 21 August 2021

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WEPAB075

Xenos: X-Ray Monte Carlo Code Suite

electron, simulation, positron, photon

2766

S. Humphries
Field Precision, Albuquerque, New Mexico, USA

Xenos is an integrated 3D code suite for the design of X-ray sources and electron beam devices. The component programs run under all versions of Windows. This paper describes unique features of Xenos compared to other Monte Carlo packages: 1) representation of geometry and deposited dose on a finite-element mesh supported by an interactive mesh generator, 2) inclusion of full 3D electric and magnetic fields in Monte Carlo simulations, 3) an integrated user environment for input and output calculations (e.g., electron gun design, target heating, …) and 4) extended parallel-computing support for high-accuracy solutions. Xenos employs the full capabilities of multi-core computers and allows parallel computations on an unlimited number of independent computers.
* Sempau J., et.al. (2003), "Experimental benchmarks of the Monte Carlo code PENELOPE", Nucl. Instrum. Meth. B 207, 107-123.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB075

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paper received ※ 10 May 2021 paper accepted ※ 23 June 2021 issue date ※ 25 August 2021

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WEPAB079

Optics Studies on the Operation of a New Wiggler and Bunch Shortening at the DELTA Storage Ring

wiggler, optics, cavity, storage-ring

2772

B. Büsing, P. Hartmann, A. Held, S. Khan, C. Mai, D. Schirmer, G. Schmidt
DELTA, Dortmund, Germany

Funding: Work supported by Deutsche Forschungsgemeinschaft via project INST 212/330-1 AOBJ: 619186
The 1.5-GeV electron storage ring DELTA is a synchrotron light source operated by the TU Dortmund University. Radiation from hard X-rays to the THz regime is provided by dipole magnets and insertion devices like undulators and wigglers. To provide even shorter wavelengths, a new 22-pole superconducting 7-T wiggler has been installed. The edge focusing of the wiggler has a large impact on the linear optics of the storage ring. Measurements regarding its influence and simulations were performed. In addition, a second radiofrequency (RF) cavity has been installed to compensate the increased energy loss per turn due to the new wiggler. As a consequence of the higher RF power, the electron bunches are shorter compared to the old setup with only one cavity. In view of reducing the bunch length even more, studies of the storage ring optics with reduced momentum compaction factor were performed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB079

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 01 September 2021

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WEPAB082

Single Bunch Instability Simulations in the Storage Ring of the ALS-U Project

impedance, simulation, cavity, storage-ring

2783

D. Wang, K.L.F. Bane, S. De Santis, M.P. Ehrlichman, D. Li, T.H. Luo, O. Omolayo, G. Penn, C. Steier, M. Venturini
LBNL, Berkeley, California, USA

As the broad-band impedance modeling and the vacuum chamber design of the new Advanced Light Source storage ring (ALS- U) reach maturity, we report on progress in single-bunch collective effects studies. A pseudo-Green function wake representing the entire ring was earlier obtained by numerical and analytical methods. Macroparticle simulations using the computer code "elegant" and this wake function are used to determine the instability thresholds for longitudinal and transverse motion. We consider various operating conditions, such as without/with higher-harmonic RF cavities, zero/finite linear chromaticity, and without/with a transverse bunch-by-bunch feedback system. Results show enough margin for the broadband impedance budget when the single-bunch instability thresholds are compared with the design bunch charge.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB082

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paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 12 August 2021

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WEPAB083

Effect of Negative Momentum Compaction Operation on the Current-Dependent Bunch Length

simulation, bunching, synchrotron, storage-ring

2786

P. Schreiber, T. Boltz, M. Brosi, B. Härer, A. Mochihashi, A.-S. Müller, A.I. Papash, R. Ruprecht, M. Schuh
KIT, Karlsruhe, Germany

Funding: Funded by the European Union’s Horizon 2020 Research and Innovation programme, Grant Agreement No 730871. P.S, T.B are supported by DFG-funded Karlsruhe School of Elementary and Astroparticle Physics.
New operation modes are often considered during the development of new synchrotron light sources. An understanding of the effects involved is inevitable for a successful operation of these schemes. At the KIT storage ring KARA (Karlsruhe Research Accelerator), new modes can be implemented and tested at various energies, employing a variety of performant beam diagnostics devices. Negative momentum compaction optics at various energies have been established. Also, the influence of a negative momentum compaction factor on different effects has been investigated. This contribution comprises a short report on the status of the implementation of a negative momentum compaction optics at KARA. Additionally, first measurements of the changes to the current-dependent bunch length will be presented.

Poster WEPAB083 [1.129 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB083

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 26 August 2021

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WEPAB100

Heat Dissipation of Photocathodes at High Laser Intensities for a New DC Electron Source

cathode, electron, experiment, laser

2826

M.A. Dehn, K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher
HIM, Mainz, Germany
K. Aulenbacher
GSI, Darmstadt, Germany

Funding: This project was supported by the German science ministry BMBF through the Verbundforschung
Laser intensities of 1W or more are required to extract average beam currents of more than 10mA from photocathodes. Most of this laser power is converted into thermal load within the cathode and has to be dissipated to avoid excessive heating of the cathode and thus a significant reduction in lifetime. At Johannes Gutenberg-University Mainz, we are developing a new high current DC electron source operating at an energy of 100keV, where an efficient heat dissipation of the photocathode is achieved by a mechanical design of the supporting structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB100

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 30 August 2021

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WEPAB129

A New Method of Undulator Phase Tuning with Mechanical Shimming

undulator, MMI, radiation, permanent-magnet

2912

M.F. Qian, R.J. Dejus, Y. Piao, I. Vasserman, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DEAC02-06CH11357.
We developed a new method for tuning the undulator phase errors by shimming the undulator gap profile mechanically. First, the phase errors of a device are calculated based on the initial field measurement; then the desired field strength modulation along the device length is derived from the phase errors; and finally, the gap profile is mechanically shimmed to produce the desire field strength modulation. The method has been successfully applied to the tuning of many new and reused APS Upgrade (APS-U) hybrid permanent magnet undulators. The method is especially effective for tuning the legacy undulators with large phase errors. For instance, an old 33-mm-period undulator with a 23 degree initial rms phase error largely due to radiation damage has been tuned to better than 3 degrees.

Poster WEPAB129 [0.500 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB129

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 13 August 2021

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WEPAB144

A New Flux Concentrator Made of Cu Alloy for the SuperKEKB Positron Source

positron, vacuum, target, GUI

2954

Y. Enomoto, K. Abe, N. Okada, T. Takatomi
KEK, Ibaraki, Japan

Flux concentrator (FC) is one of important device for positron source which translates position and momentum spread of the particles adiabatically to match them to the acceptance of the following section. To realize higher positron yield, higher magnetic field is desired. However, higher field by higher current generate stronger force on the coil. Since the gap between each turn of the coil is as narrow as 0.2 mm and the voltage across them is about as high as 1 kV at the design current, slight deformation of the coil cause discharge between the gap. To avoid such problem, a new FC made of Cu alloy which has 40 times higher yield strength than that of pure Cu was designed and tested. Finally, during summer shutdown in 2020, the old FC made of pure Cu was replaced by the new one made of Cu alloy in the KEK electron positron injector linac. The new one has been working stably at the design current, 12 kA, since Oct. 2020, and positron yield of 0.5 was realized. There were no discharge and other trouble till now.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB144

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paper received ※ 08 May 2021 paper accepted ※ 01 July 2021 issue date ※ 26 August 2021

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WEPAB177

Consideration of Triple-Harmonic Operation for the J-PARC RCS

bunching, injection, simulation, cavity

3020

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

The wideband magnetic alloy (MA) cavities are employed in the J-PARC RCS. The dual-harmonic operation, in which each MA cavity is driven by superposition of the fundamental accelerating voltage and the second harmonic voltage, significantly improves the bunching factor and is indispensable for acceleration of the high intensity beams. The original LLRF control system was replaced with the new system in 2019, which can control the amplitudes of the higher harmonics as well as the fundamental and second harmonics. Therefore we consider to use additionally the third harmonic voltage for further improvement of the bunching factor during acceleration. By the triple-harmonic operation, the flat RF bucket can be realized with a higher synchronous phase and improvement of the bunching factor is expected. In this presentation, we describe the longitudinal simulation studies of the triple-harmonic operation. Also the preliminary test results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB177

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paper received ※ 18 May 2021 paper accepted ※ 25 June 2021 issue date ※ 19 August 2021

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WEPAB179

Recent Status of J-PARC Rapid Cycling Synchrotron

shielding, synchrotron, injection, proton

3027

K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3 GeV rapid cycling synchrotron (RCS) at the Ja-pan Proton Accelerator Research Complex (J-PARC) provides more than 500 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). In such a high-intensity hadron accelerator, even losing less than 0.1% of the beam can cause many problems. Such lost protons can cause serious radio-activation and accelerator component malfunctions. Therefore, we have been continuing a beam study to achieve high-power operation. In addition, we have also improved and maintained the accelerator components to enable stable operation. This paper reports the status of the J-PARC RCS over the last two years.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB179

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paper received ※ 13 May 2021 paper accepted ※ 25 June 2021 issue date ※ 22 August 2021

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WEPAB180

Design and Beam Dynamics Studies of a Novel Compact Recoil Separator Ring for Nuclear Research with Radioactive Beams

ISOL, optics, dipole, quadrupole

3031

J. Resta-López
UVEG, Burjasot (Valencia), Spain
A.P. Foussat, G. Kirby
CERN, Geneva, Switzerland
I. Martel
University of Huelva, Huelva, Spain
V. Rodin
The University of Liverpool, Liverpool, United Kingdom
V. Rodin
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by the Generalitat Valenciana under grant agreement CIDEGENT/2019/058
The recent development of radioactive beam facilities has significantly expanded the capabilities for investigating the structure of the atomic nucleus and the nuclear interaction. For instance, the HIE-ISOLDE facility at CERN delivers presently the largest range of low-energy radioactive beam available worldwide. This energy range is ideal for the study of nuclear structure, low-energy dynamics and astrophysics by using nucleon transfer, Coulomb excitation and deep inelastic reactions. All these studies require an efficient and high-resolution recoil separator for the clear identification of medium and large mass reaction fragments. To meet these needs, we propose a versatile recoil separator for radioisotopes based on a compact storage ring, the Isolde Superconducting Recoil Separator (ISRS) formed of superconducting combined-function nested magnets with both, bending and focusing/defocusing functions. The ISRS is designed to operate in high momentum acceptance and isochronous modes. In this paper, we present the optics design and detailed beam dynamics studies for the performance characterisation.

Poster WEPAB180 [3.619 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB180

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 31 August 2021

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WEPAB192

Simulation Study on Double Diffuser for Loss Reduction in Slow Extraction at J-PARC Main Ring

simulation, extraction, proton, scattering

3069

R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, K. Okamura, Y. Shirakabe, M. Tomizawa, E. Yanaoka
KEK, Tokai, Ibaraki, Japan
A. Matsumura
Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan

J-PARC (Japan Proton Accelerator Research Complex) Main Ring delivers slow-extracted 30~GeV proton beam to various nuclear and particle physics experiments. In the slow extraction the beam loss at the electrostatic septum (ESS) is inevitable, and the beam loss reduction is a key issue to realize the high-intensity beam delivery. We carried out simulation studies on the effectiveness of the beam diffusers at the upstream of the ESS for the beam loss reduction with various materials and dimensions of the diffusers. We found out that putting two diffusers simultaneously on the beam was effective for the beam loss reduction, and the expected beam loss was 0.35 times as high as the operation without diffusers. According to the simulation results we installed the diffusers in the J-PARC Main Ring. We performed beam test with one diffuser and beam loss reduction of 60% was observed, which was in good agreement with the simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB192

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paper received ※ 19 May 2021 paper accepted ※ 28 June 2021 issue date ※ 21 August 2021

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WEPAB204

Layout of the New Septum Magnets for Fast Extraction in J-PARC Main Ring

septum, extraction, simulation, emittance

3103

S. Iwata, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Sato, T. Shibata, T. Sugimoto
KEK, Ibaraki, Japan

At J-PARC Main Ring (MR), we are pursuing to improve the beam power from 500 kW to 1.3 MW by reducing the repetition cycle from 2.48 to 1.16 seconds (1 Hz operation). Additionally, we are considering the beam particles increasing by selecting a more optimal tune. The fast extraction (FX) equipment to the neutrino facility (NU) is needed to upgrade for the 1 Hz operation. We plan to replace most FX septum magnets with new ones in 2021. We report a layout of the FX line in confirmation of new beam optics and mention the beam loss during the fast extraction.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB204

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paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

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WEPAB244

Optimization and Machine Learning Applied to the RF Manipulations of Proton Beams in the CERN PS

beam-loading, extraction, simulation, cavity

3201

A. Lasheen, H. Damerau, S.C. Johnston
CERN, Meyrin, Switzerland

The 25 ns bunch spacing in the LHC is defined by a sequence of RF manipulations in the Proton Synchrotron (PS). Multiple RF systems covering a large range of revolution harmonics (7 to 21, 42, 84, 168) allow performing RF manipulations such as beam splitting, and non-adiabatic bunch shortening. For the nominal beam sent to LHC, each bunch is split in 12 in the PS. The relative amplitude and phase settings of the RF systems need to be precisely adjusted to minimize the bunch-by-bunch variations in intensity, longitudinal emittance, and bunch shape. However, due to transient beam-loading, the ideal settings, as well as the best achievable beam quality, vary with beam intensity. Slow drifts of the hardware may also affect beam quality. In this paper, automatized optimization routines based on particle simulations with intensity effects are presented, together with the first considerations of machine learning. The optimization routines are used to assess the best achievable longitudinal beam quality expected with the PS RF systems upgrades, in the framework of the LHC Injector Upgrade project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB244

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021

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WEPAB246

Influence of Different Beam Energies on the Micro-Bunching Instability

bunching, damping, synchrotron, radiation

3209

M. Brosi, A.-S. Müller, P. Schreiber, M. Schuh
KIT, Karlsruhe, Germany

During the operation of an electron synchrotron with short electron bunches, the beam dynamics are influenced by the occurrence of the micro-bunching instability. This collective instability is caused by the self-interaction of a short electron bunch with its own emitted coherent synchrotron radiation (CSR). Above a certain threshold bunch current dynamic micro-structures start to occur on the longitudinal phase space density. The resulting dynamics depend on various parameters and were previously investigated in relation to, amongst others, the momentum compaction factor and the acceleration voltage. In this contribution, the influence of the energy of the electrons on the dynamics of the micro-bunching instability is studied based on measurements at the KIT storage ring KARA (Karlsruhe Research Accelerator).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB246

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paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 11 August 2021

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WEPAB281

The Precision Laser Inclinometer

laser, experiment, luminosity, detector

3305

B. Di Girolamo, S. Vlachos
CERN, Geneva, Switzerland
Ju. Boudagov, M.V. Lyablin
JINR, Dubna, Moscow Region, Russia

Earth surface movements, like earthquakes or human-produced (cultural) noise, can induce a degradation of the instantaneous luminosity of particle accelerators or even sudden beam losses. In the same way the presence of seismic and cultural noise limits the detection capabilities of interferometric antennas used for the observations of gravitational waves. This contribution discusses the importance of monitoring the effects of earth vibrations using a novel multi-purpose instrument, the Precision Laser Inclinometer (PLI). Few examples of recorded events are discussed along with ideas on PLI applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB281

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paper received ※ 16 May 2021 paper accepted ※ 01 July 2021 issue date ※ 12 August 2021

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WEPAB282

The Consolidation of the CERN Beam Interlock System

diagnostics, controls, interface, timing

3309

R.L. Johnson, C. Martin, T. Podzorny, I. Romera, R. Secondo, J.A. Uythoven
CERN, Geneva, Switzerland

The Beam Interlock System (BIS) is a machine protection system that provides essential interlock control throughout the CERN accelerator complex. The current BIS has been in service since 2006; as such, it is approaching the end of its operational lifetime, with most components being obsolete. A second version of the Beam Interlock System, "BIS2", is currently under development and will replace the current system. BIS2 aims to be more flexible by supplying additional on-board diagnostic tools, while also improving the overall safety by adding more redundancy. Crucially, BIS2 increases the number of critical paths that can be interlocked by almost 50%, providing an important flexibility for future additional interlocking requests. BIS2 will come into operation for the LHC in run 4 (2027) and will remain in operation until the end of the planned lifetime of HL-LHC. In this paper, we will focus on the Beam Interlock Controller Manager board (CIBM), which is at the heart of BIS2. Since this module works closely with many other systems that are similar in design to those in BIS1, we will compare how BIS2 improves upon BIS1, and justify the reasons why these changes were made.

Poster WEPAB282 [0.378 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB282

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paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 23 August 2021

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WEPAB283

CERN SPS Sprinkler System: A Customized Industrial Solution for a Non-Conventional Site

radiation, controls, monitoring, GUI

3313

A. Suwalska, A. Arnalich, F. Deperraz, M. Munoz Codoceo, P. Ninin
CERN, Meyrin, Switzerland

Until 2018, the limited firefighting means in the SPS complex largely exposed it to the consequences of self-ignition or accidental fire. In 2015 the SPS Fire Safety project was launched with the objective of improving life safety and property protection by deploying a whole set of automatic actions to protect SPS in case of fire outbreak. If nothing was done, an unmanaged fire could be a threat to lives of those working underground and could mean losing a vast majority of the SPS machine and its equipment. In 2020, CERN has completed the consolidation of its SPS fire safety systems. Among these, a water based sprinkler system, following principles of standard industrial design but customized and tailor-made for SPS and its irradiated areas, is ready to operate. The system must take into account limitations related to the presence of fragile accelerator equipment, radioactive zones, integration constraints and comply with European norms, in particular EN12845. This paper presents the risk assessment, our experience from the planning and installation phase while discussing the custom-chosen and radiation tested equipment to end up with the lessons learned and outlook for the future.

Poster WEPAB283 [2.224 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB283

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paper received ※ 13 May 2021 paper accepted ※ 14 June 2021 issue date ※ 16 August 2021

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WEPAB284

Interlock System Upgrades at the CERN Accelerator Complex During Long Shutdown 2

injection, linac, booster, extraction

3316

J.A. Uythoven, A. Antoine, C. Martin, A. Mirana Fontan, R. Mompo, I. Romera, R. Secondo
CERN, Geneva, Switzerland

The CERN accelerator complex stopped operation at the end of 2018 for the Long Shutdown 2 (LS2), allowing for the LHC Injector Upgrade program (LIU) and consolidation work to be accomplished. A gradual restart of the different accelerators is ongoing in 2021, culminating with the LHC foreseen to be back in operation early 2022. During LS2 a very large range of systems was modified throughout the accelerator complex. This includes the so-called Machine Interlock systems, which are at the heart of the overall machine protection system. This paper gives an overview of the Machine Interlock systems changes during LS2. It includes the installation of a Beam Interlock System (BIS) at the new linear accelerator LINAC4, at the PS-Booster and the installation of a new Injection BIS for the SPS synchrotron. New Safe Machine Parameter flags to protect the SPS transfer line mobile beam dumps against high intensity beams were put in place. The new Warm Magnet Controller (WIC) installations at LINAC4 the PS Booster and the different transfer lines and experimental areas are presented together with the modifications to the Power Interlock Controller protecting the LHC superconducting magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB284

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paper received ※ 17 May 2021 paper accepted ※ 02 July 2021 issue date ※ 17 August 2021

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WEPAB287

Upgrade of the ELBE Timing System

timing, gun, hardware, GUI

3326

M. Kuntzsch, M. Justus, A. Schwarz, K. Zenker
HZDR, Dresden, Germany
L. Krmpotic, U. Legat, U. Rojec
Cosylab, Ljubljana, Slovenia
Ž. Oven
COSYLAB, Control System Laboratory, Ljubljana, Slovenia

At the ELBE accelerator center a superconducting linac is operated to drive manifold secondary radiation sources like two infrared FELs, a positron source and a THz facility. The machine uses two injectors as electron sources that are accelerated in the main linac. The user experiments demand a large variety of bunch patterns from single shot to macro pulsed and cw beam at up to 26 MHz repetition rate. At ELBE a new timing system is being developed based on the MRF hardware platform and the MRF Timing System IOC. It uses two masters and a scalable number of connected receivers to generate the desired pulse patterns for operating the machine and to control user experiments. The contribution will show the architecture of the timing system, the control interfacing and performance measurements acquired on the test bench.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB287

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paper received ※ 21 May 2021 paper accepted ※ 01 July 2021 issue date ※ 13 August 2021

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WEPAB290

Pointing Stabilization Algorithms Explored and Implemented with the Low Energy RHIC Electron Cooling Laser

laser, electron, feedback, cathode

3336

L.K. Nguyen
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The electron beam for the Low Energy RHIC electron Cooler (LEReC) at Brookhaven National Laboratory (BNL) is generated by a high-power fiber laser illuminating a photocathode, with a total propagation distance of 34 m separating the laser output and the photocathode. This propagation is facilitated by three independent laser tables that have varying responses to changes in time of day, weather, and season. Alignment drifts induced by these environmental changes are mitigated by an active "slow" pointing stabilization system found along the length of the transport, and this in-house system was commissioned as part of the full laser transport in 2019, as previously reported*. In 2020, the system became fully operational alongside LEReC, the world’s first electron cooler in a collider, and helped establish the transverse stability of the electron beam required for cooling. A summary of the different slow stabilization algorithms, which were continually refined during the run in order to achieve long-term center-of-mass stability of the laser spot on the photocathode to within 10 microns RMS, is provided.
* L. K. Nguyen et al., "Active Pointing Stabilization Techniques Applied to the Low Energy RHIC Electron Cooling Laser Transport at BNL", presented at NAPAC’19, paper THYBA6.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB290

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 24 August 2021

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WEPAB293

The Trip Event Logger for Online Fault Diagnosis at the European XFEL

controls, cavity, FEL, EPICS

3344

J.H.K. Timm, J. Branlard, A. Eichler, H. Schlarb
DESY, Hamburg, Germany

The low-level RF (LLRF) system at the European XFEL, DESY, is of major importance for a high-performant and reliable operation. Faults here can jeopardize the overall operation. Therefore, the trip event logger is currently developped, - a fault diagnosis tool to detect errors online, inform the operators and trigger automatic supervisory actions. Further goals are to provide information for a fault tree and event tree analysis as well as a database of labeled faulty data sets for offline analysis. The tool is based on the C++ framework ChimeraTK Application Core. With this close interconnection to the control system it is possible not only to monitor but also to intervene as it is of great importance for supervisory tasks. The core of the tool consists of fault analysis modules ranging from simple ones (e.g., limit checking) to advanced ones (model-based, machine learning, etc.). Within this paper the architecture and the implementation of the trip event logger are presented.

Poster WEPAB293 [7.919 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB293

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021

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WEPAB299

Spallation Neutron Source Proton Power Upgrade Low-Level RF Control System Development

controls, LLRF, cavity, neutron

3363

M.T. Crofford, J.A. Ball, J.E. Breeding, M.P. Martinez, J.S. Moss, M. Musrock
ORNL, Oak Ridge, Tennessee, USA
L.R. Doolittle, C. Serrano, V.K. Vytla
LBNL, Berkeley, California, USA
J. Graham, C.K. Roberts, J.W. Sinclair, Z. Sorrell, S. Whaley
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
The Proton Power Upgrade (PPU) Project is approved for the Spallation Neutron Source at Oak Ridge National Laboratory and will double the proton beam power capability from 1.4 MW to 2.8 MW with 2 MW beam power available to the first target station. A second target station is planned and will utilize the remaining beam power in the future. The proton power increase will be supported with the addition of twenty-eight new superconducting cavities powered by 700 kW peak power klystrons to increase beam energy while increases to the beam current will be done with a combination of existing RF margin, and DTL HPRF upgrades. The original low-level RF control system has proven to be reliable over the past 15 years of operations, but obsolescence issues mandate a replacement system be developed for the PPU project. The replacement system is realized in a µTCA.4 platform using a combination of commercial off-the-shelf boards and custom hardware to support the requirements of PPU. This paper presents the prototype hardware, firmware, and software development activities along with preliminary testing results of the new system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB299

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 11 August 2021

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WEPAB302

COSY Machine-Model Optimization

dipole, simulation, betatron, optics

3375

I. Bekman, J.H. Hetzel
FZJ, Jülich, Germany

Funding: Helmholtz Association
Successful operation of a particle accelerator requires accompanying model calculations. The model helps in understanding the machine and predicts the impact of a change in the settings (e.g. current of magnetic elements). For the COoler SYnchrotron (COSY) at Research Center Jülich the accelerator simulation software MAD-X is used to model the machine. The model parameters are steadily being improved based on various manual adjustments and analytical studies, however are hardly optimized all at once. This can be improved with machine learning methods. The model is used to predict measurable quantities, like Orbit Response Matrix (ORM) or betatron tunes. Several observables for different particle energies have been measured recently and the corresponding machine settings are available. We describe the effort to improve the agreement between measured and calculated ORMs and hence improve the agreement between model and (real) machine and report on the optimization using a multivariate algorithm (e.g. genetic algorithm). This facilitates the setup of COSY and will allow to perform high precision experiments e.g. a measurement of an electric dipole moment of deuterons at COSY.

Poster WEPAB302 [1.905 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB302

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paper received ※ 14 May 2021 paper accepted ※ 28 July 2021 issue date ※ 20 August 2021

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WEPAB303

Machine Learning Applied to Automated Tunes Control at the 1.5 GeV Synchrotron Light Source DELTA

storage-ring, quadrupole, simulation, controls

3379

D. Schirmer
DELTA, Dortmund, Germany

Machine learning (ML) driven algorithms are finding more and more use cases in the domain of accelerator physics. Apart from correlation analysis in large data volumes, low and high level controls, like beam orbit correction, also non-linear feedback systems are possible application fields. This also includes monitoring the storage ring betatron tunes, as an important task for stable machine operation. For this purpose classical, shallow (non-deep), feed-forward neural networks (NNs) were investigated for automated adjusting the storage ring tunes. The NNs were trained with experimental machine data as well as with simulated data based on a lattice model of the DELTA storage ring. With both data sources comparable tune correction accuracies were achieved, both, in real machine operation and for the simulated storage ring model. In contrast to conventional PID methods, the trained NNs were able to approach the desired target tunes in fewer steps. The report summarizes the current status of this machine learning project and points out possible future improvements as well as other possible applications.

Poster WEPAB303 [1.575 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB303

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paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 25 August 2021

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WEPAB304

Multi-Objective Multi-Generation Gaussian Process Optimizer

framework, network, simulation, storage-ring

3383

X. Huang, M. Song, Z. Zhang
SLAC, Menlo Park, California, USA

Funding: DOE, Office of Science, Office of Basic Energy Sciences, DE-AC02-76SF00515 and FWP 2018-SLAC-100469 Computing Science, Office of Advanced Scientific Computing Research, FWP 2018-SLAC-100469ASCR.
We present a multi-objective evolutionary optimization algorithm that uses Gaussian process (GP) regression-based models to select trial solutions in a multi-generation iterative procedure. In each generation, a surrogate model is constructed for each objective function with the sample data. The models are used to evaluate solutions and to select the ones with a high potential before they are evaluated on the actual system. Since the trial solutions selected by the GP models tend to have better performance than other methods that only rely on random operations, the new algorithm has much higher efficiency in exploring the parameter space. Simulations with multiple test cases show that the new algorithm has a substantially higher convergence speed and stability than NSGA-II, MOPSO, and some other recent preselection-assisted algorithms.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB304

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paper received ※ 17 May 2021 paper accepted ※ 12 July 2021 issue date ※ 28 August 2021

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WEPAB320

RecCeiver-ETCD: A Bridge Between ETCD and ChannelFinder

EPICS, insertion, status, database

3424

G. Jhang, T. Ashwarya, A. Carriveau
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Managing EPICS Process Variables’~(PVs) metadata, such as the host and the contact, is one of the important tasks for the operation of large-scale accelerator facilities with minimal downtime. Record Sychronizer~(RecSync) provides a way to manage such crucial information in an EPICS Input-Output Controller~(IOC). RecCeiver-ETCD is the server component of the RecSync-ETCD, or an extension of RecCeiver for ETCD. In the previous work, the client component of RecSync, or RecCaster, has been extended to RecCaster-ETCD to store the metadata into an ETCD key-value store. An important remaining step to the production use is to introduce a connection between ETCD and ChannelFinder, which is achieved by RecCeiver in the RecSync system. RecCeiver-ETCD plays the role of the original RecCeiver in the RecSync-ETCD system. RecCeiver-ETCD is designed to perform the specific operation, bridging the communication between ETCD and ChannelFinder. In addition, its simple implementation does not hold it down to ChannelFinder and makes it easy to extend RecCeiver-ETCD out to the other applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB320

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

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WEPAB330

A Multirange Low Noise Transimpedance Amplifier for Sirius Beamlines

impedance, feedback, FEM, synchrotron

3447

L.Y. Tanio, F.H. Cardoso, M.M. Donatti
LNLS, Campinas, Brazil

In a typical synchrotron beamline, the interaction of photon beams with different materials generates free electric charges in devices such as ionization chambers, photodiodes, or even isolated metallic structures (e.g., blades, blocks, foils, wires). These free charges can be measured as electric current to diagnose the photon beam intensity, profile, position, or stability. Sirius, the new 3GeV fourth-generation Brazilian light source, may accommodate up to 38 beamlines, which combined will make use of hundreds of instruments to measure such low-intensity signals. This work reports on the design and test results of a transimpedance amplifier developed for low current measurements at Sirius’ beamlines. The device presents low noise, high accuracy, and good temperature stability providing 5 selectable ranges (from 500pA to 7.3mA) to measure bipolar currents achieving femtoampere resolution under certain conditions. Considering low bandwidth applications, the results suggest noise performance comparable to commercial bench instruments. Additionally, the project definitions and plans for the development of a family of low current ammeters will be discussed.

Poster WEPAB330 [2.642 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB330

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 21 August 2021

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WEPAB334

Development of Diffusion Bonded Joints of AA6061 Aluminum Alloy to AISI 316LN Stainless Steel for Sirius Planar Undulators

vacuum, undulator, interface, MMI

3459

R.L. Parise, O.R. Bagnato, R. Defavari, M.W.A. Feitosa, F.R. Francisco, D.Y. Kakizaki, R.D. Ribeiro
LNLS, Campinas, Brazil

LNLS has been commissioning Sirius, a 4th-generation synchrotron light source. The commissioning of the beamlines has been mainly done by using planar undulator, which uses in-house built aluminum vacuum chambers with ultra-high vacuum tight bimetallic flanges. In order to manufacture these flanges, diffusion bonded joints of AA6061 aluminum alloy to AISI 316LN stainless steel were developed. Diffusion bonding was carried out at 400-500°C for 45-60 min, applying a load of 9.8MPa in a vacuum furnace. Also, the surface preparation for Al and SS was investigated. SEM observation revealed that an 1-3 µm reaction layer was formed at the AA6061/Ni-plated interface. The intermetallic compound Al3Ni was identified in the reaction layer. The obtained Al/SS joints showed mean ultimate strength of 84 MPa, with the fracture occurring in the Al/reaction layer interface. Bake-out cycles followed by leak tests were carried out to validate the process and approve their use on the planar undulator vacuum chambers. Two undulators with Al/SS flanges have been installed and are under operation in the storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB334

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

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WEPAB338

Amorphous Carbon Coating in SPS

vacuum, electron, target, multipactoring

3475

W. Vollenberg, P. Chiggiato, P. Costa Pinto, P. Cruikshank, H. Moreno, C. Pasquino, J. Perez Espinos, M. Taborelli
CERN, Meyrin, Switzerland

Within the LHC Injector Upgrade (LIU) project, the Super Proton Synchrotron (SPS) needs to be upgraded to inject into the LHC higher intensity and brighter 25-ns bunch spaced beams. To mitigate the Electron Multipacting (E.M.) phenomenon, a well-known limiting factor for high-intensity positively charged beams, CERN developed carbon coatings with a low Secondary Electron Yield (SEY). During the 2016 & 2017 year-end technical stops, such coatings were deposited on the inner wall of the vacuum chambers of some SPS quadrupole and dipole magnets by a dedicated in-situ setup. A much larger scale deployment was implemented during the Long Shutdown 2 (2019-2020) to coat all beam pipes of focussing quadrupoles (QF) and their adjacent short straight sections. In this contribution, we remind the motivation of the project, and present the results and the quality control of the carbon coating campaign during the latter phase of implementation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB338

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 13 August 2021

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WEPAB347

Design, Construction and Testing of a Magnetic Probe for Fast Kicker Magnets

vacuum, impedance, kicker, injection

3510

N. Ayala, A. Ferrero Colomo, T. Kramer
CERN, Geneva, Switzerland

The CERN PS injection kicker has been modified in the framework of the LHC Injector Upgrade (LIU) project to allow injecting proton beams with an energy of 2 GeV. One of the most important items of the system parameter validation is the measurement and analysis of the magnetic field in the magnet aperture. To meet the required measurement precision without compromising the magnet vacuum performance, a dedicated magnetic probe has been designed, constructed and tested. The results are presented in this paper highlighting the mitigations of electrical, mechanical and vacuum complications. The paper concludes with an analysis of the probe performance during the first magnetic field measurements in the laboratory.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB347

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 02 September 2021

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WEPAB353

Design and Commissioning of a Multipole Injection Kicker for the SOLEIL Storage Ring

injection, kicker, synchrotron, storage-ring

3525

R. Ollier, P. Alexandre, R. Ben El Fekih, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

In third-generation synchrotron light sources, achieving an orbit distortion below 10% of the stored beam size is very challenging. The standard injection scheme of SOLEIL is made of 2 septa and 4 kicker magnets installed in a 12 m long straight section. Tuning the 4 kickers, to reduce perturbations, revealed to be almost impossible since it requires having 4 identical magnets, electronics, and Ti coated ceramic chambers. To reach the position stability requirement of the stored beam, a single pulsed magnet with no field on the stored beam path can replace the 4 kickers. Such a device, called MIK (Multipole Injection Kicker), was developed by SOLEIL and successfully commissioned in the MAX-IV 3-GeV ring as the key device used in the standard injection scheme for user operation, reducing the beam orbit distortion below 1 micron in peak value in both planes. A copy of the MIK has been installed in a short straight section of the SOLEIL storage ring, in January 2021. We report MIK positioning studies, the constraints of the project, sapphire chamber coating challenges and the first commissioning results. The R&D MIK is a demonstrator for the injection scheme of SOLEIL upgrade as well.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB353

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paper received ※ 21 May 2021 paper accepted ※ 23 July 2021 issue date ※ 31 August 2021

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WEPAB358

Development of Low-Z Collimator for SuperKEKB

impedance, cavity, electron, positron

3537

S. Terui, T. Abe, Y. Funakoshi, T. Ishibashi, H.N. Nakayama, K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
A. Natochii
University of Hawaii, Honolulu,, USA

Collimator jaws for SuperKEKB main ring, which is an electron-positron collider, installed to suppress background noise in a particle detector complex named Belle II. The collimators are successful to reduce backgrounds when the collimator was closed. But, in high current operations with 500 mA or more, jaws were occasionally damaged by hitting abnormal beams. This trouble is a low-frequency, which is once-a-commissioning period currently, but a high-consequence one because we are not able to apply high voltage on detectors in Belle II by high backgrounds. Low-Z collimator jaw, that is durable through hitting uncontrollable beam, have been designed due to protect important component as the solution of the trouble. The low-Z collimator jaws are installable in a present collimator chamber, have a pair of vertically opposed movable jaws. One pair of low-Z collimator jaws was installed. The paper is to describe what did we calculate and measure to make a low-Z collimator, how did we make a low-Z collimator, the impact of the installed low-Z collimator, mainly transverse mode coupling instability.

Poster WEPAB358 [0.788 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB358

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paper received ※ 16 May 2021 paper accepted ※ 22 July 2021 issue date ※ 10 August 2021

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WEPAB359

Report on Collimator Damaged Event in SuperKEKB

electron, detector, positron, MMI

3541

S. Terui, Y. Funakoshi, H. Hisamatsu, T. Ishibashi, K. Kanazawa, Y. Ohnishi, K. Shibata, M. Shirai, Y. Suetsugu, M. Tobiyama
KEK, Ibaraki, Japan

Collimator jaws for SuperKEKB main ring, which is an electron-positron collider, installed to suppress background noise in a particle detector complex named Belle II. In high current operations with 500 mA or more, jaws were occasionally damaged by hitting abnormal beams. This trouble is a low-frequency, which is once-a-commissioning period currently, but high-consequence one because we are not able to apply high voltage on detectors in Belle II by high backgrounds. At this moment this jaw damage event occurs, we observed pressure burst near the collimator with the beam abort, there was no sign of beam oscillation indicating instability, and the beam intensity suddenly decreased a few turns before the abort. I predict that the cause of this jaw damage was that a sudden change of the beam energy by the collision with dust. In this paper, the explanation of the observation result of this events and tracking simulation of beam colliding with dust are reported.

Poster WEPAB359 [3.869 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB359

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paper received ※ 17 May 2021 paper accepted ※ 22 July 2021 issue date ※ 20 August 2021

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WEPAB361

New Generation CERN LHC Injection Dump - Assembly and Installation (TDIS)

vacuum, injection, alignment, radiation

3548

D. Carbajo Perez, E. Berthomé, C. Bertone, N. Biancacci, C. Bracco, G. Bregliozzi, B. Bulat, C. Cadiou, M. Calviani, G. Cattenoz, A. Cherif, P. Costa Pinto, A. Dallocchio, M. Di Castro, P. Fessia, M.I. Frankl, R. Franqueira Ximenes, J.-F. Fuchs, H. Garcia Gavela, J.-M. Geisser, L. Gentini, S.S. Gilardoni, M.A. Gonzalez De La Aleja Cabana, J.L. Grenard, J.M. Heredia, S. Joly, A. Lechner, J. Lendaro, J. Maestre, E. Page, M. Perez Ornedo, A. Perillo-Marcone, D. Pugnat, E. Rigutto, B. Salvant, A. Sapountzis, K. Scibor, R. Seidenbinder, J. Sola Merino, M. Taborelli, E. Urrutia, A. Vieille, C. Vollinger, C. Yin Vallgren
CERN, Meyrin, Switzerland

Funding: Work supported by the Hilumi Project
During CERN’s LS2, several upgrades were performed to beam intercepting devices in the framework of the HL-LHC Project. Upgraded equipment includes two internal beam dumps (TDIS) intended for machine protection located at the injection points from the SPS to the LHC. These two devices have been assembled, tested, and installed around LHC Point 2 and Point 8 and are currently ready to get commissioned with the beam. They are 5.8m-long, three-module-segmented vacuum chambers, with large aperture to accommodate the injected and circulating beam and equipped with absorbing materials, These comprise graphite and higher Z alloys that are embedded on sub-assemblies reinforced with back-stiffeners made of TZM. The current contribution covers three main matters. First, it details the TDIS design and its key technical features. The second topic discussed is the outcome of an experiment where a prototype module was tested under high-energy beam impacts at CERN’s HiRadMat facility. To conclude it is presented the return of experience from the pre-series construction, validation and installation in the LHC tunnel.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB361

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paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021

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WEPAB363

Dynamic Response of Spallation Volume to Beam Raster on the European Spallation Source Target

target, resonance, simulation, proton

3552

Y. Lee
ESS, Lund, Sweden

To achieve a desirably low beam intensity on the target, the European Spallation Source (ESS) adopted a beam raster system at the high beta beam transport part of the linac. The raster system paints the beam on the target with frequencies up to 40 kHz within the 2.86 ms beam pulse, to form a uniformly expanded beam footprint. While the beam raster reduces the time-averaged beam current density to a level that the 5 years of design lifetime of the target system can be achieved with a high operational reliability, it could potentially induce deleterious dynamic excitations in the spallation volume made of tungsten. The stress wavelets created by raster sweeps can be amplified if the sweep frequency is in tune with a resonance mode of the tungsten volume. This coherent interference of the wavelets could lead to a high dynamic stress in tungsten, posing a risk of premature failure of the target. In this paper, the dynamic response of the spallation volume of the ESS target to different beam raster frequencies has been analysed, using multi-physics simulations based on measured material data. Finally, a safe operational range of the beam raster frequency band is proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB363

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paper received ※ 12 May 2021 paper accepted ※ 02 July 2021 issue date ※ 01 September 2021

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WEPAB365

CERN BDF Prototype Target Operation, Removal and Autopsy Steps

target, radiation, extraction, interface

3559

R. Franqueira Ximenes, O. Aberle, C. Ahdida, P. Avigni, M. Battistin, L. Bianchi, L.R. Buonocore, S. Burger, J. Busom, M. Calviani, J.P. Canhoto Espadanal, M. Casolino, M. Di Castro, M.A. Fraser, S.S. Gilardoni, S. Girod, J.L. Grenard, D. Grenier, M. Guinchard, R. Jacobsson, M. Lamont, E. Lopez Sola, A. Ortega Rolo, A. Perillo-Marcone, Y. Pira, B. Riffaud, V. Vlachoudis, L. Zuccalli
CERN, Meyrin, Switzerland

The Beam Dump Facility (BDF), currently in the study phase, is a proposed general-purpose fixed target facility at CERN. Initially will host the Search for Hidden Particles (SHiP) experiment, intended to investigate the origin of dark matter and other weakly interacting particles. The BDF particle production target is located at the core of the facility and is employed to fully absorb the high intensity (400 GeV/c) Super Proton Synchrotron (SPS) beam. To validate the design of the production target, a downscaled prototype was tested with the beam at CERN in 2018 in the North Area primary area in a dedicated test at 35 kW average beam power. This contribution details the BDF prototype target operation, fully remote removal intervention, and foreseen post-irradiation examination plans.

Poster WEPAB365 [1.691 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB365

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 25 August 2021

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WEPAB366

Towards the Last Stages of the CERN’s AD-Target Area Consolidation Project and Recommissioning Plans to Resume Operation

target, proton, antiproton, MMI

3563

C. Torregrosa, C. Ahdida, A. Bouvard, A. Broche, S. Burger, M.E.J. Butcher, M. Calviani, V. Clerc, A. De Macedo, S. De Man, F.A. Deslande, M. Di Castro, T. Dobers, T. Feniet, R. Ferriere, E. Fornasiere, R. Franqueira Ximenes, T.J. Giles, J.L. Grenard, E. Grenier-Boley, G. Gräwer, M. Guinchard, M.D. Jedrychowski, K. Kershaw, B. Lefort, E. Lopez Sola, J.M. Martin Ruiz, A. Martínez Sellés, G. Matulenaite, C.Y. Mucher, A. Newborough, M. Perez Ornedo, E. Perez-Duenas, A. Perillo-Marcone, L. Ponce, N. Solieri, M.B. Szewczyk, P.A. Thonet, M.A. Timmins, A. Tursun, W. Van den Broucke, F.M. Velotti, C. Vendeuvre, V. Vlachoudis
CERN, Meyrin, Switzerland
J.C. Espadanal
LIP, Lisboa, Portugal

Antiprotons are produced at CERN at the Antiproton Decelerator (AD) Target Area by impacting 26 GeV/c proton beams onto a fixed target. Further collection, momentum selection, and transport of the secondary particles - including antiprotons - towards the AD ring is realised by a 400 kA pulsed magnetic horn and a set of magnetic dipoles and quadrupoles. A major consolidation of the area - in operation since the 80s - has taken place during the CERN Long Shutdown 2 (2019-2021). Among other activities, such upgrade included: (i) Installation of a new air-cooled target design and manufacturing of a new batch of magnetic horns, including a surface pulsing test-bench for their validation and fine-tuning (ii) Installation of a new positioning and maintenance system for the target and horn (iii) Refurbishment and decontamination of the Target Area and its equipment, (iv) Construction of a new surface service building to house new nuclear ventilation systems. This contribution presents an overview of such activities and lesson learnt. In addition, it provides the latest results from refractory metals R&D for the antiproton target and a summary of the recommissioning and optimization plans.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB366

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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WEPAB367

Bubble Generation in the SNS 2 MW Mercury Target

target, injection, proton, experiment

3567

C.N. Barbier, M.P. Costa, K.C. Johns, D. Ottinger, F. Rasheed, B.W. Riemer, R.L. Sangrey, J.R. Weinmeister, D.E. Winder
ORNL, Oak Ridge, Tennessee, USA

The accelerator at the Spallation Neutron Source is currently being upgraded to increase the proton beam power from 1.4 MW to 2.8 MW. About 2 MW will go to the first target station, while the rest will go to the future second target station. The first target station uses a mercury target. When the short proton beam pulse hits it, strong pressure waves are developed inside the mercury and the vessel itself, causing weld failures and cavitation erosion. The pressure wave can be significantly mitigated by injecting small helium bubbles into the mercury. SNS has been injecting helium since 2017 using small orifices but has met challenges in fabrication and operations with them. Thus, for the 2 MW target, swirl bubblers will be used to increase gas injection and improve reliability. A 2 MW prototypical target was built and tested in a mercury process loop available at Oak Ridge National Laboratory. Acrylic viewports on the top of the target were used to determine the bubble size distribution (BSD) generated by the swirl bubblers. It was found that the bubblers were not only capable of generating small bubbles but that the BSD was independent of gas injection rate.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB367

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paper received ※ 10 May 2021 paper accepted ※ 22 June 2021 issue date ※ 20 August 2021

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WEPAB368

Sigraflex® Studies for LHC CERN Beam Dump: Summary and Perspective

experiment, target, radiation, extraction

3571

J.M. Heredia, M. Calviani, R. Franqueira Ximenes, D. Grenier, K. Kershaw, A. Lechner, P.A. Andreu-Muñoz, F.-X. Nuiry, A. Perillo-Marcone, V. Rizzoglio, C. Torregrosa
CERN, Geneva 23, Switzerland
A. Alvaro
SINTEF, Trondheim, Norway
F. Berto, S. Solfiti
NTNU, Trondheim, Norway

The Large Hadron Collider (LHC) beam dump (TDE) is essential for safe and reliable operation of the collider. It absorbs particles extracted from the accelerator whenever required. The original design of the TDE dates from the mid 2000 and it is constituted of an eight-meter-long cylindrical stainless-steel tube, filled with low-Z carbon-based materials from different grades and densities. The Sigraflex®, an expanded low-density graphite, is employed in the middle section of the TDE core. Due to unexpected behaviour observed in the past LHC runs, several major upgrades were recently implemented in order for the TDE to be ready for LHC Run3 (2021-2024), where up to 555 MJ beam energy is expected to be dumped every few hours. According simulations, temperatures in the Sigraflex core will reach locally up to 1500°C in the regular dump cases, and above 2300°C for failure scenarios. The objective of this contribution is to summarize the LS2 hardware upgrades and the plan for the evaluation of the Sigraflex performance during LHC Run3. This work will also detail the last experimental and numerical findings applied to the Sigraflex®, and possible alternative materials for the future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB368

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paper received ※ 18 May 2021 paper accepted ※ 11 August 2021 issue date ※ 16 August 2021

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WEPAB372

Design and Construction of Uninterruptible Paralleling Transfer Switches for an Emergency Power System in Taiwan Light Source

controls, cryogenics, ECR, MMI

3581

Y.F. Chiu, W.S. Chan, K.C. Kuo, Y.-C. Lin
NSRRC, Hsinchu, Taiwan

The ATS of an emergency power system in Utility Building II has operated over 18 years; in recent years the failure rate is gradually increasing because of aged components. To improve old switches, schemes of upgrading and developing new and efficient transfer switches have been conducted cautiously. A new device named an Uninterruptible Paralleling Transfer Switch (UPTS) is designed and implemented to replace an existing ATS to enhance the performance to meet the requirements of uninterrupted power transfer. The UPTS can uninterruptedly switch the grid power to emergency power of a backup generator during a planned utility power outage, and also exactly switch emergency power to the grid power uninterruptedly when the utility power is restored. If grid power is unexpectedly lost, UPTS acts like a typical ATS, automatically transferring power from a primary source to a backup source with switching duration a few seconds. A practical UPTS has been assembled and installed in Utility Building II and has performed well effectively to eliminate power-switching transients.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB372

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paper received ※ 11 May 2021 paper accepted ※ 02 July 2021 issue date ※ 12 August 2021

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WEPAB373

The Energy Management System in NSRRC

network, controls, MMI, radiation

3585

C.S. Chen, W.S. Chan, Y.Y. Cheng, Y.F. Chiu, Y.-C. Chung, K.C. Kuo, M.T. Lee, Y.C. Lin, C.Y. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

Taiwan has been suffering from a shortage of natural resources for more than two decades. As stated by the Energy Statistics Handbook 2019 of Taiwan, up to 97.90% of energy supply was imported from abroad. This kind of energy consumption structure is fragile relatively. Not mention to the total domestic energy consumption annual growth rate is 1.97% in twenty years. Either the semiconductor or the integrated circuit-related industry is developed vigorously in Taiwan. All the facts cause us to face the energy problems squarely. Therefore, an energy management system (EnMS) was installed in NSRRC in 2019 to pursue more efficient energy use. With the advantages of the Archive Viewer - a utility supervisory control and data acquisition system in NSRRC, the data of energy use could be traced conveniently and widely. The model of energy use has been built to review periodically, furthermore, it provides us the accordance to replace the degraded equipment and alerts us if the failure occurs.

Poster WEPAB373 [0.497 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB373

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paper received ※ 21 May 2021 paper accepted ※ 22 July 2021 issue date ※ 11 August 2021

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WEPAB376

The Inner Triplet String Facility for HL-LHC: Design and Planning

cryogenics, quadrupole, vacuum, MMI

3592

M.B. Bajko, S. Bertolasi, C. Bertone, S. Blanchard, D. Bozzini, O.S. Brüning, P. Cruikshank, D. De Luca, N. Dos Santos, F. Dragoni, N. Heredia Garcia, A. Herty, A. Kosmicki, S. Le Naour, W. Maan, A. Martínez Sellés, P. Martinez Urios, P. Orlandi, A. Perin, M. Pojer, F. Rodriguez-Mateos, G. Rolando, L. Rossi, H. Thiesen, E. Todesco, E. Vergara Fernandez, D. Wollmann, S. Yammine, J.J. Zawilinski, M. Zerlauth
CERN, Geneva, Switzerland

In the framework of the HL-LHC project, full-scale integration and operational tests of the superconducting magnet chain, from the inner triplet quadrupoles up to the first separation/recombination dipole, are planned in conditions as similar as possible to the final set-up in the LHC tunnel. The IT String includes all of the required systems for operation at nominal conditions, such as vacuum, cryogenics, warm and cold powering equipment, and protection systems. The IT String is intended to be both an assembly, and an integration test stand, and a full rehearsal of the systems working in unison. It will, closely reproducing the mechanical, electrical, and thermo-hydraulic interfaces of the final installation, as well as allowing a full rehearsal of the systems working in unison. This paper describes the conceptual design, the test stand’s reference configuration, and the main goals. It also summarizes the status of the main activities, including the detailed design of the test infrastructure, procurement of main equipment, the baseline installation schedule, and major milestones. The first version of the experimental program and the associated planning are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB376

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

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WEPAB379

Photocathode Laser Development for Superconducting X-Ray Free Electron Lasers at DESY

laser, FEL, cathode, electron

3599

C. Li, O. Akcaalan, U. Grosse-Wortmann, I. Hartl, C. Mohr, M. Seidel, H. Tuennermann, C. Vidoli, L. Winkelmann
DESY, Hamburg, Germany
M. Frede, O. Puncken
neoLASE GmbH, Hanover, Germany

Funding: Deutsches Elektronen-Synchrotron, Hamburg, 22609, Germany
Modern X-Ray Free-Electron Lasers (XFEL) are a key tool to enable a variety of scientific research. Those large-scale machines rely on robust and reliable deep ultraviolet (DUV) laser sources to drive electrons from their RF photocathode gun. In this paper we present a new photocathode laser prototype, which offers more flexibility in duration and shape of the 257.5 nm pulses for driving the CsTe Photocathodes of DESY’s superconducting burst-mode FELs. The laser matches the FEL pulse structure, which are 800 µs bursts at up to 4.5 MHz intraburst-rate with 10 Hz burst-repetition-rate. In a first version the system will offer variable DUV pulse durations, tunable from 1 ps to 20 ps to address different operational regimes of the XFEL. The laser system comprises a high-resolution spectral shaper with the option of generating flat-top DUV pulses for reducing electron-beam emittance at a later version. The laser is constructed in a hybrid Yb:fiber and Yb:YAG architecture. Our prototype delivers 180 uJ pulse energy at 1030 nm and 1 MHz intra-burst rate and we demonstrated conversion of 50µJ of the NIR beam to DUV, resulting 11.5µJ at 21ps (FWHM) and 6.15 µJ at 1.05 ps (FWHM) pulse duration.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB379

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paper received ※ 27 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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WEPAB387

Study of Failure Modes in Electron Linac-Based X-Ray Sources for Industrial Applications

linac, gun, electron, vacuum

3622

K.P. Dixit, G. Vinod
BARC, Mumbai, India

Electron linac-based X-ray sources (XRS) have an increased demand in industrial applications, mainly for their advantages of compactness and ease of use. In order to achieve reliable operation, it is necessary to have rugged components in the linac system. Hence, this study focusses on achieving high reliability design; also in formulating a preventive maintenance programme to optimise the availability and prognostic methods for performance monitoring of components. This paper investigates the failure modes in the important sub-systems of a 6 MeV electron linac, including electron gun, RF power source, vacuum system, x-ray target, control system, etc. Electron guns suffer from problems related to the filament heater damage and high voltage insulation failure. In the RF source, major components (line-type pulsed modulators, magnetrons, circulator and RF window) are studied to assess their life. Fault tree analysis of the individual sub-systems and the effect of individual failures on the linac down-time are studied. A few mitigation techniques used in practical systems are also discussed here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB387

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paper received ※ 18 May 2021 paper accepted ※ 23 July 2021 issue date ※ 29 August 2021

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WEPAB390

High-Quality, Conformal Bellows Coatings Using Ultra-Fast HiPIMS with Precision Ion Energy Control

plasma, vacuum, target, experiment

3626

T.J. Houlahan, I. Haehnlein, W.M. Huber, B.E. Jurczyk, I.A. Shchelkanov, R.A. Stubbers
Starfire Industries LLC, Champaign, USA

Funding: This material is based upon work supported by the U.S. Department of Energy under Award Number DE-SC0020481.
In this paper we demonstrate a replacement for traditional ’wet’ chemical deposition processes using a vacuum, ionized physical vapor deposition (iPVD) process that results in a conformal metal film, capable of coating complex, convoluted parts that are common in modern particle accelerators (e.g., bellows, RF cavities). Results are presented for a process utilizing the combined deposition and etching that are achieved using ultra-fast high-power impulse magnetron sputtering (HiPIMS) coupled with precision control of the ion energy using a positive voltage reversal. This process results in a conformal film and has been used to coat both test coupons and full bellows assemblies. The resulting Cu films, which are 5-10 µm in thickness, exhibit excellent adhesion. Further, they have been shown to tolerate temperature extremes ranging from 77 K to a 400 C vacuum bakeout as well as extreme plastic deformation of the substrate without any buckling, cracking, or delamination.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB390

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 31 August 2021

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WEPAB397

Design of the Two-Layer Girder for Accelerating Tube

neutron, ECR, acceleration, simulation

3636

X.J. Nie, H.Y. He, L. Kang
IHEP, Beijing, People’s Republic of China
J.X. Chen, L. Liu, R.H. Liu, C.J. Ning, A.X. Wang, G.Y. Wang, Y.J. Yu, J.S. Zhang, D.H. Zhu
IHEP CSNS, Guangdong Province, People’s Republic of China
J.B. Yu
DNSC, Dongguan, People’s Republic of China

An accelerating tube is one kind of important acceleration equipment of a linear accelerator. It is often made up of oxygen-free copper with a long tubular structure. It’s easy to suffer from deformation. Based on support requirements, the reasonable structure of the girder was obtained. Four supporting blocks were installed on the top surface of aluminum profile with the uniform distribution along the beam direction. The support strength with static condition and different working conditions were checked by ANSYS simulation calculation to ensure the stable operation of the girder. The two-layer girder can be used as a reference for other similar slender part for its simple structure and reliable support.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB397

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paper received ※ 14 May 2021 paper accepted ※ 01 September 2021 issue date ※ 22 August 2021

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WEPAB410

Finite Element Analyses of Synchrotron Radiation Induced Stress in Beryllium Synch-Light Mirrors

dipole, simulation, synchrotron, scattering

3664

Y. Lushtak, Y. Li, A. Lyndaker
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Air Force Research Laboratory Directorate for Mathematical and Physical Sciences National Institute of General Medical Sciences Empire State Development - NYSTAR
Mirrors made of high purity beryllium are used in particle accelerators to extract synchrotron radiation (SR) in the visible range for transverse and longitudinal particle beam profile measurements. Be is a high-strength, high thermal conductivity material. As a low-Z metal, it allows high-energy photons to penetrate the mirror body, so that majority of the SR power is dissipated, resulting in a significantly reduced thermal stress and distortion on the mirror surface. In this paper, we describe a Finite Element Analysis method of accurately simulating the SR-induced thermal stress on the beryllium mirrors at the Cornell Electron Storage Ring at various particle beam conditions. The simulations consider the energy dependence of X-ray attenuation in beryllium. The depth-dependent distribution of the power absorbed by the mirror is represented by separate heating zones within the mirror model. The results help set the operational safety limit for the mirrors-ensuring that the SR-induced thermal stress is below the elastic deformation limit and estimate the mirror surface distortion at high beam currents. The simulated surface distortion is consistent with optical measurements.

Poster WEPAB410 [0.942 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB410

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 02 September 2021

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WEPAB411

Ion Coulomb Crystals in Storage Rings for Quantum Information Science

storage-ring, controls, laser, rfq

3667

K.A. Brown, G.J. Mahler, T. Roser, T.V. Shaftan, Z. Zhao
BNL, Upton, New York, USA
A. Aslam, S. Biedron, T.B. Bolin, C. Gonzalez-Zacarias, S.I. Sosa Guitron
UNM-ECE, Albuquerque, USA
R. Chen, T.G. Robertazzi
Stony Brook University, Stony Brook, New York, USA
B. Huang
SBU, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We discuss the possible use of crystalline beams in storage rings for applications in quantum information science (QIS). Crystalline beams have been created in ion trap systems and proven to be useful as a computational basis for QIS applications. The same structures can be created in a storage ring, but the ions necessarily have a constant velocity and are rotating in a circular trap. The basic structures that are needed are ultracold crystalline beams, called ion Coulomb crystals (ICC’s). We will describe different applications of ICC’s for QIS, how QIS information is obtained and can be used for quantum computing, and some of the challenges that need to be resolved to realize practical QIS applications in storage rings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB411

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

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WEPAB416

Industrialization Study of the Accelerating Structures for a 380 GeV Compact Linear Collider

survey, linear-collider, collider, factory

3674

A. Magazinik
Tampere University, Tampere, Finland
N. Catalán Lasheras
CERN, Meyrin, Switzerland
S. Mäkinen
Tampere University of Technology, Tampere, Finland
J. Sauza-Bedolla
Lancaster University, Lancaster, United Kingdom

The LHC at CERN will continue its operation for approximately 20 years. In parallel, diverse studies are conducted for the design of a future large-scale accelerator. One of the options is the Compact Linear Collider (CLIC) who aims to provide a very high accelerating gradient (100 MV/m) achieved by using normal conducting radiofrequency (RF) cavities operating in the X-band range (12 GHz). Each accelerating structure is a challenging component involving ultra-precise machining and diffusion bonding techniques. The first stage of CLIC operates at a collision energy of 380 GeV with an accelerator length of 11 km, consisting of 21630 accelerating structures. Even though the prototypes have shown a mature and ready to build concept, the present number of qualified suppliers is limited. Therefore, an industrialization study was done through a technical survey with hi-tech companies. The aim is to evaluate current capabilities, to ensure the necessary manufacturing yield, schedule, and cost for mass production. This paper presents the results of the industrialization study for 12 GHz accelerating structures for CLIC 380 GeV, highlighting the principal challenges towards mass production.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB416

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

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THXA02

Overview of the Micro-Bunching Instability in Electron Storage Rings and Evolving Diagnostics

bunching, electron, simulation, diagnostics

3686

M. Brosi
KIT, Karlsruhe, Germany

The micro-bunching instability is a longitudinal instability that leads to dynamical deformations of the charge distribution in the longitudinal phase space. It affects the longitudinal charge distribution, and thus the emitted coherent synchrotron radiation spectra, as well as the energy distribution of the electron bunch. Not only the threshold in the bunch current above which the instability occurs, but also the dynamics above the instability threshold strongly depends on machine parameters, e.g., natural bunch length, accelerating voltage, momentum compaction factor, and beam energy. All this makes the understanding and potential mitigation or control of the micro-bunching instability an important topic for the next generation of light sources and circular e⁺/e⁻ colliders. This presentation will give a review on the micro-bunching instability and discuss how technological advances in the turn-by-turn and bunch-by-bunch diagnostics are leading to a deeper understanding of this intriguing phenomenon.

Slides THXA02 [23.626 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA02

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 31 August 2021

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THXB04

Non-Invasive Dispersion Function Measurement during Light Source Operations

lattice, synchrotron, storage-ring, emittance

3720

B. Podobedov, Y. Hidaka
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We implemented a completely parasitic measurement of lattice dispersion functions in both horizontal and vertical planes, which is fully compatible with light source user operations. The measurement is performed by applying principal component analysis and adaptive filtering to very small residual orbit noise components introduced by the RF system and detected in the beam orbit data, sampled at 10 kHz. No changes in RF frequency are required. The measurement, performed once a minute, was shown to be robust and immune to changes in the beam current, residual orbit noise amplitude and frequency content as well as other factors. At low current it was shown to provide similar accuracy to the traditional method (which shifts the 500 MHz RF frequency by ±500 Hz). In this paper we will explain our measurement technique and present typical dispersion function stability achieved during NSLS-II operations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB04

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paper received ※ 26 June 2021 paper accepted ※ 13 July 2021 issue date ※ 23 August 2021

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THXB05

Inverse Orbit Response Matrix Measurements: A Possible On-Line Tool for Optics Control in Storage Rings

quadrupole, optics, storage-ring, insertion

3724

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

We propose a novel technique to measure the linear optics in storage rings based on the acquisition of the inverse orbit response matrix (iORM). The iORM consists in the orbit correctors magnets (OCM) strength changes needed to produce a local orbit variation in each beam position monitor (BPM). This measurement can be implemented by introducing sequentially small changes in the BPM offsets and logging the OCM setting variations when the orbit correction is running. Very high precision and accuracy in the OCM set-points is required which poses a considerable challenge. Since the orbit feedback (FOFB) is kept running, the iORM could potentially be acquired in parallel to users storage ring operation. Since the iORM is very linear and local, optics perturbations could be easily diagnosed online. This paper introduces the iORM measurement concept and presents the progress of these studies at ALBA, where the implementation of this technique is limited by hysteresis effects in the OCM and the FOFB performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB05

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paper received ※ 19 May 2021 paper accepted ※ 29 July 2021 issue date ※ 12 August 2021

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THXB06

Results of the First Alignment Run for Sirius

alignment, network, laser, survey

3728

R. Junqueira Leão, R. Oliveira Neto
CNPEM, Campinas, SP, Brazil
H. Geraissate, F. Rodrigues, G.R. Rovigatti de Oliveira
LNLS, Campinas, Brazil

It is widely known that the position of particle accelerator components is critical for its performance. For the latest generation light sources, whose magnetic lattice is optimized for achieving very low emittance, the tolerable misalignments are in the order of a few dozen micrometers. Due to the perimeter of these machines, the requirements push the limits of large-volume dimensional metrology and associated instruments and techniques. Recently a fine alignment campaign of the Sirius accelerators was conducted following the pre-alignment performed during the installation phase. To conform with the strict relative positioning demands, measurement good practices were followed, and several 3D metrology procedures were developed. Also, to improve positioning resolution, high rigidity translation devices were produced. Finally, the special target holders designed as removable fiducials for the magnets were revisited to assure maximum reliability. Data processing algorithms were implemented to evaluate the alignment results in a robust and agile manner. This paper will present the final positioning errors for Sirius magnets with an expression of the estimated uncertainty.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB06

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 01 September 2021

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THXC03

Evolution of the High-Power Spallation Neutron Mercury Target at the SNS

target, neutron, injection, proton

3735

D.E. Winder
ORNL, Oak Ridge, Tennessee, USA

Funding: UT-Battelle, LLC, under Grant DE-AC05-00OR22725 with the US Department of Energy (DOE).
The Spallation Neutron Source (SNS) began operation in 2006 and first operated at its full 1.4 MW power in 2013. Targets, which receive the pulsed proton beam, were a limiting factor for reliable full power operation for several years. Reaching reliable target operation at 1.4 MW required not only changes to the target design but also support and coordination across the entire SNS enterprise. The history and some key lessons learned are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXC03

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

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THXC07

Adaptive Control of Klystron Operation Parameters for Energy Saving at Storage Ring of TPS

klystron, controls, cathode, storage-ring

3748

T.-C. Yu, F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

To satisfy maximum beam current operation in the storage ring of TPS, the operation parameters of both RF transmitters are set to be able to generate its maxi-mum RF power in daily usage. Under such condition, the klystrons can deliver any power below 300kW at constant AC power consumption which is about 520-530 kW. Hence, the AC power usage is independent of the required RF output power. To best utilize the avail-able AC power based on the required RF power, an adaptive control methodology is proposed here to change the operation parameters of the klystron, cath-ode voltage and anode voltage, according to the pre-sent RF power. The corresponding operation parame-ters are applied by the prior tested table which maps the operation parameters with the different saturation RF power. The test results show that the saved energy can be 32% to 11% from 30mA to 450mA for both RF plants as comparing to constant operation parameters of 1047 kW AC power.

Slides THXC07 [1.241 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXC07

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 11 August 2021

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THPAB001

Reaching the Sub Per Mil Level Coupling Corrections in the LHC

coupling, quadrupole, simulation, dipole

3752

E.J. Høydalsvik, T.H.B. Persson
CERN, Geneva, Switzerland

The High Luminosity LHC (HL-LHC) is requiring sub per mil coupling correction, as defined by the closest tune approach. In this article, the current coupling correction strategy is analyzed in order to understand if it can robustly correct to these very low levels. The impact of realistic errors on the coupling correction is investigated with MAD-X simulations, including the influence of local coupling on the global coupling correction. Through simulations and measurements in the LHC, the effect of BPM noise on the coupling correction is analyzed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB001

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paper received ※ 11 May 2021 paper accepted ※ 28 July 2021 issue date ※ 23 August 2021

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THPAB036

Superconducting Phase Shifter Design for the Afterburner at the European XFEL

electron, FEL, undulator, photon

3823

V. Grattoni, J.E. Baader, S. Casalbuoni
EuXFEL, Schenefeld, Germany

At the European XFEL, a superconducting afterburner is under design for the SASE2 hard X-ray beamline. It will consist of 5 undulator modules. One module corresponds to two superconducting undulator (SCU) coils of 2 m length plus one phase shifter. Such an afterburner will enable photon energies above 30 keV. Superconducting (SC) phase shifters will be installed in each undulator module to keep the correct phase delay between the electron beam and photon beam. In this contribution, we present the required SC phase shifter parameters to enable operation in the electron beam energy range 11.5-17.5 GeV. We also analyze different magnetic designs satisfying the calculated specifications.

Poster THPAB036 [0.991 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB036

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 12 August 2021

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THPAB055

Reconstruction of Linear Optics Observables Using Supervised Learning

optics, simulation, target, MMI

3875

E. Fol, H. Garcia, R. Tomás García
CERN, Meyrin, Switzerland

In the LHC, most of the optical functions can be obtained from turn-by-turn beam centroid data. However, the measurement of such observables as β^* and the dispersion function require special dedicated techniques and additional operational time. In this work, we propose an alternative approach to estimate these observables using supervised machine learning, in case the dedicated measurements are not available but turn-by-turn data are. The performance of developed estimators is demonstrated on LHC simulations. Comparison to traditional techniques for the computation of beta-function will be also provided.

Poster THPAB055 [0.713 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB055

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

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THPAB074

ESRF-EBS: Implementation, Performance and Restart of User Operation

SRF, MMI, storage-ring, emittance

3929

J.-L. Revol, P. Berkvens, J.-F. Bouteille, N. Carmignani, L.R. Carver, J.M. Chaize, J. Chavanne, F. Ewald, A. Franchi, L. Hardy, J. Jacob, L. Jolly, G. Le Bec, I. Leconte, S.M. Liuzzo, D. Martin, J. Pasquaud, T.P. Perron, Q. Qin, P. Raimondi, B. Roche, K.B. Scheidt, R. Versteegen, S.M. White
ESRF, Grenoble, France

The European Synchrotron Radiation Facility - Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. In December 2019, the first beam was stored and accumulated in the storage ring, allowing the vacuum conditioning and tuning to be started. The beam was delivered to beamlines in March 2020 for their commissioning. On 25 August, the user programme was restarted with beam parameters very close to nominal values. In this report, the milestones and key aspects of the return to user-mode operation are presented and discussed.

Poster THPAB074 [2.864 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB074

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paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 01 September 2021

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THPAB082

Recent Operational Experience with Thermionic RF Guns at the APS

gun, linac, cathode, injection

3959

Y. Sun, M. Borland, G.I. Fystro, X. Huang, H. Shang
ANL, Lemont, 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
The electron beam at the Argonne Advanced Photon Source (APS) is generated from an S-band thermionic RF gun. There are two locations at the frontend of the linac where thermionic RF guns are installed – RG1 and RG2. Three so-called generation-III guns are available, two are installed at RG1 and RG2, one is a spare. In recent years, these guns are showing signs of aging after over a couple of decades of operations. RF trips started to occur, and we had to reduce the nominal operating rf power to alleviate the problem. In addition, beam generated by RG1 suffers from low transportation efficiency from the gun to the linac, and beam trajectory is unstable which results in charge instabilities. Recently, APS obtained a new type of prototype gun and it was beam commissioned in the linac. In this paper, we report our operational experience with these thermionic rf guns including thermionic-cathode beam extraction, gun front-end optimization for maximum charge transmission through the linac, linac lattice setup to match beam for injection into the Particle Accumulator Ring (PAR) and optimization for maximum PAR injection efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB082

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 26 August 2021

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THPAB169

A Mechanism for Emittance Growth Based on Non-Linear Islands in LHC

octupole, emittance, ECR, resonance

4082

E.H. Maclean, M. Giovannozzi, T.H.B. Persson, R. Tomás García
CERN, Geneva, Switzerland

Landau octupoles are used in the LHC to prevent coherent instabilities of the circulating beam. The reduction of their strength occurring during the energy ramp can transport particles in nonlinear islands to larger amplitude. This has the potential to lead to emittance growth and to beam-losses. Beam-based studies and simulations of emittance growth during Landau octupole ramps performed in the LHC are presented to explore this mechanism in more detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB169

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

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THPAB172

Bunch Luminosity Variations in LHC Run 2

luminosity, emittance, injection, experiment

4094

I. Efthymiopoulos, S.D. Fartoukh, G. Iadarola, N. Karastathis, S. Papadopoulou, Y. Papaphilippou
CERN, Geneva, Switzerland

The LHC is designed to collide intense bunches of protons with tightly defined conditions, aimed to maximize the delivered recorded integrated luminosity to the experiments. One of these conditions is the maximum level of bunch-to-bunch fluctuation in the luminosity, in particular when levelling at maximum acceptable event rate at the experiments. Analysis results of the bunch-to-bunch luminosity variations in LHC Run 2 are presented here. In particular, the observed correlations with the LHC filling pattern that can enhance the effects introducing bunch-dependent losses or emittance blow-up from injection to collisions are discussed. In Run 2 conditions, bunch-by-bunch luminosity fluctuations reached 10% at the start of collisions and gradually increased with time, without affecting the experiments as the luminosity was not levelled. Projections for Run 3 and HL-LHC operation are discussed along with envisaged mitigation measures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB172

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paper received ※ 18 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021

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THPAB181

AI-ML Developments for the ATLAS Ion Linac Facility

rfq, linac, experiment, simulation

4122

B.M. Mustapha, B.R. Blomberg, C. Dickerson, J.L. Martinez Marin, C.E. Peters
ANL, Lemont, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357. This research used the ATLAS facility, which is a DOE Office of Nuclear Physics User Facility.
ATLAS is a DOE/NP User Facility for the study of low-energy nuclear physics with heavy ions. It operates ~6000 hours per year. In addition to delivering any stable beam from proton to uranium, the facility also provides radioactive beams from the CARIBU source or via the in-flight radioactive ion separator, RAISOR. The facility uses 3 ion sources and services 6 target areas at energies from ~1-15 MeV/u. To accommodate the large number and variety of approved experiments, ATLAS reconfigures once or twice per week over 40 weeks of operation per year. The startup time varies from ~12-48 hours depending on the complexity of the tuning, which will increase with the upcoming Multi-User Upgrade to deliver beam to two experimental stations simultaneously. DOE/NP has recently approved a project to use AI/ML to support ATLAS operations. The project aim is to significantly reduce the accelerator tuning time and improve machine performance by developing and deploying artificial intelligence methods. These improvements will increase the scientific throughput of the facility and the quality of the data collected. Our recent developments and future plans will be presented and discussed.

Poster THPAB181 [1.034 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB181

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paper received ※ 06 June 2021 paper accepted ※ 28 July 2021 issue date ※ 12 August 2021

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THPAB185

Solution to Beam Transmission Decline in the CSNS Linac Operation Using Measurements and Simulations

rfq, DTL, linac, emittance

4134

J. Peng, M.T. Li, X.H. Lu, X.B. Luo
IHEP CSNS, Guangdong Province, People’s Republic of China
Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China

The CSNS linac operation at its design average power currently. However, the beam transmission is declining and the beam loss is increasing during the operation. With simulations and experiments, we found there is a long longitudinal tail exist in the beam bunch output from the RFQ. And this tail caused the beam loss in the following linac. After inhibition of the longitudinal tail in the beam bunch, the beam transmission in operation can keep stable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB185

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 02 September 2021

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THPAB235

Detailed Electromagnetic Characterisation of HL-LHC Low Impedance Collimators

impedance, simulation, collimation, factory

4258

A. Kurtulus, C. Accentura, N. Biancacci, F. Carra, F. Caspers, N. Chitnis, F. Giordano, R. Illan Fiastre, S. Joly, I. Lamas Garcia, L. Mourier, E. Métral, S. Redaelli, B. Salvant, W. Vollenberg, C. Vollinger, C. Zannini
CERN, Geneva, Switzerland

The High Luminosity Large Hadron Collider (HL-LHC) project will upgrade the LHC machine to allow operation with increased luminosity for the experiments. In order to achieve this goal, different operational parameters of the machine need to be pushed beyond the present design values, including the stored beam energy. One of the main challenges related to the achievement of the upgraded performance is the beam collimation system and its contribution to the overall machine impedance budget. In this perspective, new low impedance collimators have been designed, fabricated, and installed in the LHC. In this study, we will present their detailed electromagnetic (EM) characterization by means of radio frequency (RF) measurements and EM simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB235

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021

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THPAB245

A Simulation Study of Beam Pipe Eddy Current Effects on Beam Optics

quadrupole, simulation, vacuum, power-supply

4288

T. Asami, T. Koseki
The University of Tokyo, Graduate School of Science, Tokyo, Japan
S. Igarashi, T. Koseki, Y. Kurimoto, Y. Sato
KEK, Ibaraki, Japan

In synchrotrons, fast changes of magnetic field induce eddy currents at the wall of beam pipes. The eddy currents cause a phase delay between excitation currents of the magnets and the magnetic field. The undesired magnetic field affected by eddy currents might be a serious obstacle in controlling beam optics precisely. In fact, in the operation of a high-intensity proton synchrotron J-PARC MR, the largest beam loss is observed at the beginning of acceleration when the magnetic field starts to vary in time. Therefore, it is important to estimate and understand the effects of eddy currents on beam optics. In this study, we have calculated the effect of eddy currents on magnetic field for some magnets in J-PARC MR, using electromagnetic simulation software. In this paper, we would like to report the details and results of the simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB245

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paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 17 August 2021

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THPAB250

Fire Detection System Reliability Analysis: An Operational Data-Based Framework

framework, detector, database, controls

4296

M.M.C. Averna, G. Gai
CERN, Meyrin, Switzerland

This paper describes a framework developed at CERN, conducting reliability analysis of Safety-Critical Systems (Fire detection and Alarms) based on operational data. It applies Fault-Tree Analysis on maintenance-related data, categorized based on the component on failure. This framework, a tool implemented in Python, accounts for Fire Detection components installed in tunnels and surface buildings (control panels, detectors, etc) and safety functions triggered upon detection (evacuation, alarms to the CERN Fire Brigade, compartmentalization, electrical isolation, etc). The usefulness of the results of this type of analysis is twofold. Firstly, the results are a supporting tool for estimating the yearly availability of Fire Detection Systems in critical facilities, crucial in Capital and Operational Expenditure identification. Additionally, this approach refines the frequency analysis as part of quantitative fire risk assessments performed in the context of the FIRIA (Fire-Induced Radiological Integrated Assessment) Project, launched by CERN in 2018 and aiming at assessing the risk of fire events in experimental facilities with potential radiologic consequences to the public.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB250

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

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THPAB252

Machine Learning for Improved Availability of the SNS Klystron High Voltage Converter Modulators

klystron, controls, real-time, high-voltage

4303

G.C. Pappas
ORNL RAD, Oak Ridge, Tennessee, USA
D. Lu
ORNL, Oak Ridge, Tennessee, USA
M. Schram
JLab, Newport News, Virginia, USA
D.L. Vrabie
PNNL, Richland, Washington, USA

Funding: SNS/ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
Beam availability has increased at the SNS, however, the targeted availability is greater than 95 %, while the SNS has failed to meet lower targets in the past. The HVCM used to power the linac klystrons have been one source of lost beam time and was chosen to explore using AI/ML techniques to improve reliability. Among the possibilities being explored are automating the tuning of HVCMs and predicting component failures such as capacitor aging, rectifier assemblies containing hundreds of diodes, and insulating oil degradation. The methodology pursued includes data cleaning, de-noising, post-analysis data labeling, and machine learning model development. We explore using Long Short-Term Memory and autoencoders for anomaly detection and prognostication used to schedule maintenance. We evaluate the use of model regularizers and constraints to improve the performance of the model and investigate methods to estimate the uncertainty of the models to provide a robust prediction with statistical interoperability. This paper describes the operational experience and known failures of the HVCMs and the proposed ML methodology and the preliminary results of training the AI/ML algorithms.
* G. Dodson, Approach to Reliable Operations, 26-Dodson_Approach to Reliable Operation-r1.pdf, Feb., 2010.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB252

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paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 29 August 2021

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THPAB259

High Level Applications for Sirius Accelerators Control

controls, EPICS, MMI, interface

4314

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

Sirius is a 4th generation 3 GeV synchrotron light source that has just finalised the first commissioning phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. The large number of process variables and large complexity of the subsystems in this type of machine requires the development of tools to simplify the commissioning and operation of the accelerators. This paper describes some of the high level control tools developed for the accelerators commissioning and future operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB259

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

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THPAB260

Detection and Classification of Collective Beam Behaviour in the LHC

extraction, controls, injection, network

4318

L. Coyle, F. Blanc, T. Pieloni, M. Schenk
EPFL, Lausanne, Switzerland
X. Buffat, M. Solfaroli Camillocci, J. Wenninger
CERN, Meyrin, Switzerland
E. Krymova, G. Obozinski
SDSC, Lausanne, Switzerland

Collective instabilities can lead to a severe deterioration of beam quality, in terms of reduced beam intensity and increased beam emittance, and consequently a reduction of the collider’s luminosity. It is therefore crucial for the operation of the CERN’s Large Hadron Collider to understand the conditions in which they appear in order to find appropriate mitigation measures. Using bunch-by-bunch and turn-by-turn beam amplitude data, courtesy of the transverse damper’s observation box (ObsBox), a novel machine learning based approach is developed to both detect and classify these instabilities. By training an autoencoder neural network on the ObsBox amplitude data and using the model’s reconstruction error, instabilities and other phenomena are separated from nominal beam behaviour. Additionally, the latent space encoding of this autoencoder offers a unique image like representation of the beam amplitude signal. Leveraging this latent space representation allows us to cluster the various types of anomalous signals.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB260

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

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THPAB272

Validation of Two Re-Buncher Cavities under High Beam Loading for LIPAc

cavity, LLRF, beam-loading, MEBT

4343

D. Gavela, I. Podadera, F. Toral
CIEMAT, Madrid, Spain
I. Moya
Fusion for Energy, Garching, Germany
F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan

Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC-A-2011-0654 and FIS2013-40860-R
Two re-buncher cavities were installed at the Medium Energy Beam Transport line of the LIPAc accelerator, presently being commissioned at Rokkasho (Japan). They are IH-type cavities with five gaps providing an effective voltage of 350 kV at 175 MHz for a nominal operation of 125 mA CW deuterons at 5 MeV. After full conditioning and beamline integration in Europe, the cavities were installed in the accelerator with special care given to the alignment with respect to the rest of the components. The RF line, cooling circuits, and instrumentation were also mounted. The cavities were operated with an FPGA-based LLRF system. A re-conditioning of the cavities was performed in the first place, followed by tests with a pulsed beam with increasing currents. A maximum pulsed beam current of 100 mA was reached while operating the buncher cavities, under which they reached voltages up to 340 kV and 260 kV respectively. As expected, the beam loading was significant, leading to a series of difficulties and required strategies for a good operation that are discussed in this paper. The effect on the beam dynamics, measured by beam position monitors downstream of the bunchers is also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB272

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

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THPAB286

Quadrupole Focusing Lenses for Heavy Ion Linac

DTL, focusing, quadrupole, flattop

4359

V. Skachkov, A.V. Kozlov, G. Kropachev, T. Kulevoy, D.A. Liakin, O.S. Sergeeva, V.S. Skachkov, Yu. Stasevich
ITEP, Moscow, Russia

Simulation results of pulsed current electromagnet quadrupoles with integral of the magnetic field gradient up to 7 T are presented. Magnets for the DTL and MEBT focusing channels are designing for the heavy-ion linac in Institute for Theoretical and Experimental Physics (ITEP - NRC "Kurchatov Institute"). Appropriate conditions which promise getting the magnetic lens parameters required at restrictions on the overall length <130 mm as well as on the beam aperture >45 mm are defined. It is shown that the channel acceptance to beam emittance ratio desired not less than 3 can be provided by conventional low-carbon steel up to a magnetic aperture of 50 mm in diameter while beyond this size permendur is out of competition. Some aspects of the pulsed power supply system are considered and main parameters of the pulse current generator (PCG) are given.

Poster THPAB286 [0.701 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB286

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paper received ※ 14 May 2021 paper accepted ※ 30 June 2021 issue date ※ 02 September 2021

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THPAB322

Transient Beam Loading in the CBETA Multi-Turn ERL

cavity, linac, beam-loading, SRF

4422

N. Banerjee
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by NSF Grant No. DMR0807731, DOE Award No. DE-SC0012704, and NYSERDA Agreement No. 102192.
The Cornell-BNL ERL Test Accelerator (CBETA) is the first superconducting multi-turn ERL that has been commissioned at Cornell University in a low current mode. In this paper, we first discuss a new model of beam loading which is valid for the low injection energies used in CBETA. Using this model, we explore the effect of bunch patterns, beam turn-on, and turn-off transients on the fundamental mode of the 7-cell SRF cavities used in the main linac. In particular, we examine the operational constraints on the rf system at the design current of 40 mA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB322

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paper received ※ 20 May 2021 paper accepted ※ 29 July 2021 issue date ※ 16 August 2021

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THPAB328

Tapered Modular Quadrupole Magnet to Reduce Higher-Order Optical Aberrations

quadrupole, focusing, simulation, optics

4429

Y.Z. Shao, G.E. Lawler, B. Naranjo, J.B. Rosenzweig
UCLA, Los Angeles, USA

Funding: US Department of Energy under the contract Nos. DE-SC0017648, DE-SC0009914 and National Science Foundation Grant No. PHY-1549132m
At UCLA’s SAMURAI Laboratory, there will be a need for beam optics to accommodate operation over a range of beam energies. We present a modular quadrupole design that, in addition to satisfying this requirement, incorporates interchangeable tapered end-pieces for mitigation of higher-order aberrations *. The design progresses in an iterative fashion, whereby the tapered shapes, generated algorithmically, are fed into a field solver, and then the aberrations of the resulting particle trajectories are calculated and minimized.
* R. Baartman, Quadrupole shapes, Phys. Rev. ST Accel. Beams 15, 074002 (2012).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB328

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 20 August 2021

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THPAB336

Novel Magnetron Operation and Control Methods for Superconducting RF Accelerators

controls, injection, cavity, SRF

4442

G.M. Kazakevich, R.P. Johnson
Muons, Inc, Illinois, USA
T.N. Khabiboulline, G.V. Romanov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

High power magnetrons designed and optimized for industrial heating, being injection-locked, have been suggested to power superconducting RF cavities for accelerators due to lower cost and higher efficiency. However, standard operation methods do not provide high efficiency with wideband control suppressing microphonics. We have developed and experimentally verified novel methods of operating and controlling the magnetron that provide stable RF generation with higher efficiency and lower noise than other RF sources. By our method the magnetrons operate with the anode voltage notably lower than the self-excitation threshold improving its performance. This is also a promising way to increase tube reliability and longevity. A magnetron operating with the anode voltage lower than the self-excitation threshold, in so-called stimulated coherent generation mode has special advantage for pulse operation with a gated injection-locking signal. This eliminates the need for expensive pulsed HV modulators and additionally increases the magnetron RF source efficiency due to absence of losses in HV modulators.

Poster THPAB336 [0.960 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB336

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paper received ※ 15 May 2021 paper accepted ※ 08 July 2021 issue date ※ 22 August 2021

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THPAB347

Status of Sirius Storage Ring RF System

cavity, storage-ring, MMI, controls

4470

A.P.B. Lima, D. Daminelli, R.H.A. Farias, F.K.G. Hoshino, F.S. Oliveira, R.R.C. Santos, M.H. Wallner
LNLS, Campinas, Brazil

The design configuration of the Sirius Light Source RF System is based on two superconducting RF cavities and eight 60 kW solid state amplifiers operating at 500 MHz. The current configuration, based on a 7-cell room temperature cavity, was initially planned for commissioning and initial tests of the beamlines. However, it will have to remain in operation longer than planned. Sirius has been operating in decay mode for beamline tests with an initial current of 70 mA. We present an overview of the first-year operation of the RF system and the preparations for the installation of the two superconducting cavities, which is expected to take place in 2023.

Poster THPAB347 [1.322 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB347

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paper received ※ 16 May 2021 paper accepted ※ 23 July 2021 issue date ※ 26 August 2021

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THPAB354

Deployment and Commissioning of the CERN PS Injection Kicker System for Operation with 2 GeV Beams in Short Circuit Mode

kicker, injection, MMI, controls

4489

T. Kramer, N. Ayala, J.C.C.M. Borburgh, P.A.H. Burkel, E. Carlier, L. Ducimetière, L.M.C. Feliciano, A. Ferrero Colomo, M.A. Fraser, L.A. Govertsen, R. Noulibos, S. Pavis, L. Sermeus
CERN, Geneva, Switzerland

Within the framework of the LHC Injector Upgrade (LIU) project, the feasibility and design of an upgrade of the existing CERN PS proton injection kicker system have been outlined in previous publications already. This paper describes the adjustments of final design choices, testing, and deployment as well as the validation and commissioning of the new 2 GeV injection kicker system. The upgrade pays particular attention to the reduction of pulse reflections unavoidably induced by a magnet in short circuit mode configuration whilst keeping a fast 10⁴ ns rise and fall time. An adapted thyratron triggering system to reduce jitter and enhance thyratron lifetime is outlined. Additionally, improvements to the magnet entry box and the elimination of SF6 gas in the magnet connection box and the associated pulse transmission lines are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB354

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paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021

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THPAB364

Mu*STAR: A System to Consume Spent Nuclear Fuel While Economically Generating Nuclear Power

site, target, neutron, proton

4499

R.P. Johnson, R.J. Abrams, M.A. Cummings, S.A. Kahn, J.D. Lobo, T.J. Roberts
Muons, Inc, Illinois, USA

Mu*STAR is a superconducting-accelerator driven, subcritical, molten-salt reactor designed to consume the spent nuclear fuel (SNF) from today’s commercial fleet of light water reactors. In the process of doing so it will: 1. generate electricity in a cost-competitive manner, 2. significantly reduce the waste-stream volume per Gigawatt-hour generated, 3. greatly reduce the radio-toxic lifetime of the waste stream. As many states and countries now prohibit licensing of new nuclear plants until a national strategy has been established for the long-term disposal of their nuclear waste, Mu*STAR can be an important enabler for new nuclear facilities. This is especially important in the light of climate change, as nuclear energy is the only carbon-free technology for a base-load generation that is readily expandable.

Poster THPAB364 [0.497 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB364

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paper received ※ 20 May 2021 paper accepted ※ 12 July 2021 issue date ※ 02 September 2021

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FRXA01

Full Energy On-Demand Beam Injection from SACLA into the SPring-8 Storage Ring

injection, electron, FEL, linac

4508

H. Maesaka, T. Fukui, T. Hara, T. Hiraiwa, T. Inagaki, E. Iwai, H. Tanaka, K. Togawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Dewa, T. Fujita, K. Fukami, N. Hosoda, A. Kiyomichi, M. Masaki, S. Matsubara, T. Ohshima, M. Oishi, K. Soutome, S. Takano, T. Watanabe
JASRI/SPring-8, Hyogo-ken, Japan
C. Kondo
JASRI, Hyogo, Japan

The beam injector for the SPring-8 storage ring (SR) was switched from the booster synchrotron to the SACLA linac, a driver for X-ray free-electron laser (XFEL). The low-emittance beam from SACLA (~100 pm rad, 8 GeV) is delivered to the SR through a 600m-long beam transport line. This low-emittance beam can be applied to the new low-emittance storage ring after the SPring-8 upgrade planed in the coming years. The shutdown of the booster synchrotron and 1-GeV linac saves energy consumption and operation cost. To provide the electron beam injected to the SR on demand for the top-up injection during the XFEL operation, the SACLA linac must be synchronized to the desired bucket of the SR, the beam energy and route must be switched shot-to-shot, and the XFEL performance must not be degraded. We developed a precise synchronization system, on-demand beam route and parameter switching system, a pulsed magnet for the switchyard, isolated bunch purification system, etc. In this presentation, we will show the design and performance of each component for the beam injection and the results from beam commissioning of the accelerator and transport line.

Slides FRXA01 [3.446 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXA01

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 31 August 2021

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FRXB07

Injector Optimization for the IR-FEL Operation at the Compact ERL at KEK

emittance, FEL, gun, laser

4531

O.A. Tanaka, N. Higashi, T. Miyajima
KEK, Ibaraki, Japan

Funding: Work supported by NEDO project "Development of advanced laser processing with intelligence based high-brightness and high-efficiency laser technologies (TACMI project)".
The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator to develop ERL technologies and to operate with a high average beam current and a high beam quality. cERL consists of a photoinjector, a main linac for energy recovery, a recirculation loop and a beam dump. A recent upgrade of the cERL to the middle Infrared Free Electron Laser (IR-FEL) imposed new conditions to maintain beam parameters. Therefore, the injector should be optimized to meet the following requirements at the exit of the main linac. The rms bunch length should be 2 ps, the rms longitudinal emittance should be kept the least, and simultaneously the rms transverse emittance should be kept less than 3 c mm mrad. In this work we describe the strategy and results of the injector optimization to achieve the better performance of the cERL-FEL.

Slides FRXB07 [3.450 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXB07

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

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FRXC05

Gas Jet In-Vivo Dosimetry for Particle Beam Therapy

diagnostics, proton, cyclotron, GUI

4548

J. Wolfenden, N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
Medical applications of charged particle beams require a full online characterisation of the beam to ensure patient safety, treatment efficacy, and facility efficiency. In-vivo dosimetry, measurement of delivered dose during treatment, is a significant part of this characterisation. Current methods offer limited information or are invasive to the beam, meaning measurements must be done offline. This contribution presents the development of a non-invasive gas jet in-vivo dosimeter for treatment facilities. The technique is based on the interaction between a particle beam and a supersonic gas jet curtain, which was originally developed for the high luminosity upgrade of the large hadron collider (HL-LHC). To demonstrate the medical application of this technique, an existing HL-LHC test system with minor modifications will be installed at the University of Birmingham’s 35 MeV proton cyclotron, which has properties comparable to that of a treatment beam. This contribution presents the design and development of this test setup, plans for initial benchmarking measurements, and plans for a future optimised medical accelerator gas jet in-vivo dosimeter.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC05

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paper received ※ 18 May 2021 paper accepted ※ 23 July 2021 issue date ※ 11 August 2021

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