IPAC2021 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOXB02	First Results of the IOTA Ring Research at Fermilab	electron, optics, lattice, octupole	19
	A. Valishev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, B.L. Cathey, S. Chattopadhyay, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari Fermilab, Batavia, Illinois, USA A. Arodzero, A.Y. Murokh, M. Ruelas RadiaBeam, Santa Monica, California, USA D.L. Bruhwiler, J.P. Edelen, C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA S. Chattopadhyay, S. Szustkowski Northern Illinois University, DeKalb, Illinois, USA A. Halavanau, Z. Huang, V. Yakimenko SLAC, Menlo Park, California, USA M. Hofer TU Vienna, Wien, Austria M. Hofer, R. Tomás García CERN, Geneva, Switzerland K. Hwang, C.E. Mitchell, R.D. Ryne LBNL, Berkeley, California, USA K.-J. Kim ANL, Lemont, Illinois, USA K.-J. Kim, Y.K. Kim, N. Kuklev, I. Lobach University of Chicago, Chicago, Illinois, USA T.V. Shaftan BNL, Upton, New York, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling and quantum science experiments. In this talk we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented will be the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXB02
About •	paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021
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MOPAB004	JSPEC - A Simulation Program for IBS and Electron Cooling	electron, simulation, emittance, scattering	49
	H. Zhang, S.V. Benson, M.W. Bruker, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. Intrabeam scattering is an important collective effect that can deteriorate the properties of a high-intensity beam, and electron cooling is a method to mitigate the IBS effect. JSPEC (JLab Simulation Package for Electron Cooling) is an open-source program developed at Jefferson Lab, which simulates the evolution of the ion beam under the IBS and/or the electron cooling effect. JSPEC has been benchmarked with BETACOOL and experimental data. In this report, we will introduce the features of JSPEC, including the friction force calculation, the IBS expansion rate and electron cooling rate calculation, and the beam-dynamic simulations for the electron cooling process; explain how to set up the simulations in JSPEC; and demonstrate the benchmarking results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB004
About •	paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 27 August 2021
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MOPAB008	Exploiting the Beam-Beam Wire Demonstrators in the Next LHC Run 3	octupole, luminosity, operation, 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, operation, 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	operation, luminosity, electron, emittance	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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MOPAB014	First High Spin-Flip Efficiency for High Energy Polarized Protons	polarization, resonance, dipole, proton	84
	H. Huang, J. Kewisch, C. Liu, A. Marusic, W. Meng, F. Méot, P. Oddo, V. Ptitsyn, V.H. Ranjbar, T. Roser 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 order to minimize the systematic errors for the Relativistic Heavy Ion Collider (RHIC) spin physics experiments, flipping the spin of each bunch of protons during the stores is needed. Experiments done with single RF magnet at energies less than 2 GeV have demonstrated a spin-flip efficiency over 99%. At high energy colliders with Siberian snakes, a single magnet spin flipper does not work because of the large spin tune spread and the generation of multiple, overlapping resonances. Over past decade, RHIC spin flipper design has evolved and a sophisticated spin flipper, constructed of nine-dipole magnets, was developed to flip the spin in RHIC. A special optics choice was also used to make the spin tune spread very small. In recent experiment, 97% spin-flip efficiency was measured at both 24 and 255 GeV for the first time. The results show that efficient spin flipping can be achieved at high energies.
	Poster MOPAB014 [0.984 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB014
About •	paper received ※ 16 May 2021 paper accepted ※ 08 June 2021 issue date ※ 20 August 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	alignment, beam-losses, emittance, operation	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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MOPAB024	Efficient Coupling of Hydrodynamic and Energy-Deposition Codes for Hydrodynamic-Tunnelling Studies on High-Energy Particle Accelerators	simulation, target, coupling, proton	119
	C. Wiesner, F. Carra, J. Kruse-Hansen, M. Masci, D. Wollmann CERN, Meyrin, Switzerland Y. Nie KIT, Karlsruhe, Germany
	The machine-protection evaluation of high-energy accelerators comprises the study of beyond-design failures, including the direct beam impact onto machine elements. In case of a direct impact, the nominal beam of the Large Hadron Collider (LHC) would penetrate more than 30 meters into a solid copper target. The penetration depth due to the time structure of the particle beam is, thus, significantly longer than predicted from purely static energy-deposition simulations with 7 TeV protons. This effect, known as hydrodynamic tunnelling, is caused by the beam-induced density depletion of the material at the target axis, which allows subsequent bunches to penetrate deeper into the target. Its proper simulation requires, therefore, to sequentially couple an energy-deposition code and a hydrodynamic code for the different target densities. This paper describes a method to efficiently couple the simulations codes Autodyn and FLUKA based on automatic density assignment and input file generation, and presents the results achieved for a sample case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB024
About •	paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 28 August 2021
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MOPAB026	RHIC Delayed Abort Experiments	kicker, injection, quadrupole, dipole	126
	M. Valette, D. Bruno, K.A. Drees, K.M. Hartmann, G. Heppner, K. Mernick, C. Mi, J.-L. Mi, R.J. Michnoff, J. Morris, F. Orsatti, E. Rydout, T. Samms, J. Sandberg, V. Schoefer, C. Schultheiss, T.C. Shrey, C. Theisen 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. For RHIC to operate at its top energy (100 GeV/n) while protecting the future sPHENIX detector, spontaneous and asynchronous firing of abort kicker modules (pre-fires) have to be avoided. A new triggering circuit for the abort kickers was implemented with relatively slow mechanical relays in series with the standard fast thyratron tubes. The relays prevents unwanted pre-fires during operation, but comes at the expense of a long latency - about 7 milliseconds - between the removal of beam permit and the actual firing of the abort kickers. Protection considerations of RHIC’s superconducting magnets forbid delaying energy extraction from the main dipoles and quadrupoles for too long after a quench. The beam has thus to circulate in both RHIc rings for a few milliseconds as the current in dipole and quadrupole circuit is being extracted. We present the results of delayed abort experiments conducted in July 2018 with the analysis of fast orbit and tune measurements and discuss the safety implications of this implementation for future RHIC operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB026
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 23 August 2021
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MOPAB029	Burn-Off with Asymmetric Interaction Points	luminosity, emittance, simulation, controls	138
	R. Tomás García, I. Efthymiopoulos, G. Iadarola CERN, Geneva, Switzerland
	LHC can host above 2700 proton bunches per ring providing collisions in the ATLAS, CMS, LHCb and ALICE interaction points. ATLAS and CMS are placed symmetrically so that they feature the same colliding bunch pairs. However this is not the case for LHCb, hence introducing unwanted bunch-by-bunch variations of the bunch intensity as the physics fill evolves. We present first analytical derivations, numerical simulations and experimental data in different bunch train collision configurations.
	Poster MOPAB029 [1.502 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB029
About •	paper received ※ 13 May 2021 paper accepted ※ 25 May 2021 issue date ※ 27 August 2021
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MOPAB034	VEPP-4M Collider Operation at High Energy	collider, luminosity, electron, positron	155
	P.A. Piminov, G.N. Baranov, A.V. Bogomyagkov, V.M. Borin, V.L. Dorokhov, S.E. Karnaev, K.Yu. Karyukina, V.A. Kiselev, E.B. Levichev, O.I. Meshkov, S.I. Mishnev, I.A. Morozov, I.N. Okunev, E.A. Simonov, S.V. Sinyatkin, E.V. Starostina, A.N. Zhuravlev BINP SB RAS, Novosibirsk, Russia
	VEPP-4M is an electron positron collider equipped with the universal KEDR detector for HEP experiments in the beam energy range from 1 GeV to 6 GeV. A unique feature of VEPP-4M is the high precision beam energy calibration by resonant polarization technique which allows conducting of interesting experiments despite the low luminosity of the collider. Recently we have started new luminosity acquisition run above 2 GeV. The hadron cross section was measured from 2.3 GeV to 3.5 GeV has been done. The luminosity run for gamma-gamma physics has been started. The luminosity at ψ(1S)-meson has been obtained. For the beam energy calibration the laser polarimeter is used. The paper discusses recent results from VEPP-4M collider.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB034
About •	paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 22 August 2021
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MOPAB077	Anomaly Detection in Accelerator Facilities Using Machine Learning	power-supply, operation, GUI, 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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MOPAB084	Acceptance Tests and Installation of the IVU and Front End for the XAIRA Beamline of ALBA	undulator, photon, vacuum, insertion	318
	J. Campmany, J. Marcos, V. Massana ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	XAIRA is a new beamline being built at ALBA synchrotron for macromolecular crystallography (MX) devoted to the study of small bio crystals. It aims at providing a full beam with a size of 3x1 µm² FWHM (hxv) and flux of >3·10¹² ph/s (250 mA in Storage Ring) at 1 Å wavelength (12.4 keV) to tackle MX projects for which only tiny (<10 μm) or imperfect crystals are obtained. Besides, XAIRA aims at providing photons at low energies, down to 4 keV, to support MX experiments exploiting the anomalous signal of the metals naturally occurring in proteins (native phasing), which is enhanced in the case of small crystals and long wavelengths. To this end, an in-vacuum undulator has been built by a consortium between Kyma and Research Instruments companies. In this paper, we present the results of the Site Acceptance Tests made at ALBA using a new bench developed to measure closed structures, and also the steps done for its installation in the ALBA tunnel.
	Poster MOPAB084 [1.715 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB084
About •	paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 25 August 2021
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MOPAB096	Rocking Curve Imaging Experiment at SSRL 10-2 Beamline	photon, wiggler, radiation, lattice	357
	A. Halavanau, R. Arthur, B. Johnson, J.P. MacArthur, G. Marcus, R.A. Margraf, Z. Qu, T. Rabedeau, T. Sato, C.J. Takacs, D. Zhu SLAC, Menlo Park, California, USA
	Stanford Synchrotron Radiation Lightsource (SSRL) serves a wide scientific community with its variety of X-ray capabilities. Recently, we have employed a wiggler source located at beamline 10-2 to perform high resolution rocking curve imaging (RCI) of diamond and silicon crystals. In-house X-ray RCI capability is important for the upcoming cavity-based x-ray source development projects at SLAC, such as cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO). In this proceeding, we describe theoretical considerations, and provide experimental results, validating the design of our apparatus. We also provide a plan for future improvements of the RCI@SSRL program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB096
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 10 August 2021
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MOPAB098	LCLS Multi-Bunch Improvement Plan	laser, FEL, linac, electron	365
	A. Halavanau, S. Carbajo, F.-J. Decker, A.K. Krasnykh, A.A. Lutman, A. Marinelli, C.E. Mayes, D.C. Nguyen SLAC, Menlo Park, California, USA
	Current and future experiments at LCLS require XFEL pulse trains of variable time separation. The cavity based XFEL (CBXFEL) project requires multiple pulses separated by 220 ns, the X-ray Laser Oscillator (XLO) uses 15 ns spaced pulse trains and Matter under Extreme Conditions (MEC) experiments need a shortly spaced (less than 5 ns) pulse trains. In this proceeding, we discuss the LCLS multi-bunch improvement plan and report on its recently status and progress.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB098
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 20 August 2021
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MOPAB100	Progress Report on Population Inversion-Based X-Ray Laser Oscillator	FEL, laser, electron, radiation	373
	A. Halavanau, R. Alonso-Mori, A. Aquila, U. Bergmann, D. DePonte, F.-J. Decker, F. Fuller, M. Liang, A.A. Lutman, C. Pellegrini SLAC, Menlo Park, California, USA M. Doyle UCB, Berkeley, USA
	The population inversion X-ray Laser Oscillator (XLO) is a fully coherent, transform limited hard X-ray source. It operates by repetitively pumping inner-shell atomic transitions with an XFEL, in a closed Bragg cavity. XLO will produce very bright monochromatic X-ray pulses for applications in quantum optics, X-ray interferometry and metrology. We report the progress to build the first XLO operating at the copper alpha line, using LCLS 9 keV SASE X-ray pulses as a pump.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB100
About •	paper received ※ 20 May 2021 paper accepted ※ 29 July 2021 issue date ※ 02 September 2021
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MOPAB101	Hollow and Flat Electron Beam Generation at FACET-II	electron, emittance, wakefield, quadrupole	376
	A. Halavanau, S.J. Gessner, C.E. Mayes SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA
	In this proceeding, we investigate hollow and flat electron beam generation at FACET-II facility. We focus on the case of a circular beamlet arrangement, also known as ’necklace’ beams. We study, via numerical simulations, the resulting e-beam dynamics in the FACET-II photoinjector, beam propagation through the high energy section, as well as possible experimental applications of the ’necklace’ beams. Finally, we evaluate the feasibility of high charge flat beam generation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB101
About •	paper received ※ 23 May 2021 paper accepted ※ 27 July 2021 issue date ※ 23 August 2021
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MOPAB132	The Multi-Mega-Watt Target Station for the European Spallation Source Neutrino Super Beam	target, proton, hadron, ion-source	466
	E. Baussan, E. Bouquerel, L. D’Alessi, M. Dracos, P. Poussot, J. Thomas, J. Wurtz, V. Zeter IPHC, Strasbourg Cedex 2, France P. Cupial, M. Koziol, L.J. Lacny, J. Snamina AGH University of Science and Technology, Kraków, Poland I. Efthymiopoulos CERN, Meyrin, Switzerland T. Tolba University of Hamburg, Hamburg, Germany
	Funding: This project has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 777419 and also by the Deutsche Forschungsgemeinschaft No 423761110. One of the next challenges in fundamental physics is to understand the origin of matter/antimatter asymmetry in the Universe. In particular, intense neutrinos could play an important role to elucidate this mystery and better understand the expansion of the Universe. The ESSnuSB collaboration proposes to use the proton linac of the European Spallation Source currently under construction in Lund (Sweden) to produce a very intense neutrino super beam, in parallel with the spallation neutron production. A very challenging part of the proposed facility is the Target Station which will have to afford 5 MW proton beam power. This poster will present the hadronic collector and the whole facility to produce the next generation of neutrino superbeam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB132
About •	paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 18 August 2021
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MOPAB134	Normalized Transverse Emittance Reduction via Ionization Cooling in MICE ’Flip Mode’	emittance, simulation, solenoid, betatron	474
	P.B. Jurj Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Low emittance muon beams are central to the development of a Muon Collider and can significantly enhance the performance of a Neutrino Factory. The international Muon Ionization Cooling Experiment (MICE) has recorded several million individual muon tracks passing through a liquid hydrogen or a lithium hydride absorber and has demonstrated the ionization cooling of muon beams. Previous analysis used a restricted data set, and the beam matching was not perfect. In this analysis, beam sampling routines were employed to account for imperfections in beam matching at the entrance into the cooling channel and enable an improvement of the cooling measurement. A study of the normalized transverse emittance change in the MICE cooling channel set up in a flipped polarity magnetic field configuration is presented. Additionally, the evolution of the canonical angular momentum across the absorber is shown and the characteristics of the cooling effect are discussed.
	Poster MOPAB134 [1.821 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB134
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021
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MOPAB137	Interaction Region Design for DWA Experiments at FACET-II	electron, radiation, alignment, diagnostics	478
	O. Williams, G. Andonian, A. Fukasawa, W.J. Lynn, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, Y. Sakai, M. Yadav, Y. Zhuang UCLA, Los Angeles, California, USA C.I. Clarke, M.J. Hogan, B.D. O’Shea, D.W. Storey, V. Yakimenko SLAC, Menlo Park, California, USA M. Ruelas RadiaBeam, Santa Monica, California, USA M. Yadav The University of Liverpool, Liverpool, United Kingdom
	Funding: DOE HEP Grant DE-SC0009914 The extremely intense beam generated at FACET-II provides the unique opportunity to investigate the effects of beam-driven GV/m fields in dielectrics exceeding meter-long interaction lengths. The diverse range of phenomena to be explored, such as material response in the terahertz regime, suppression of high-field pulse damping effects, advanced geometry structures, and methods for beam break up (BBU) mitigation, all within a single UHV vacuum vessel, requires flexibility and precision in the experimental layout. We present here details of the experimental design for the dielectric program at FACET-II. Specifically, consideration is given to the alignment of the dielectric structures due to the extreme fields associated with the electron beam, as well as implementation of electron beam and Cherenkov radiation-based diagnostics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB137
About •	paper received ※ 19 May 2021 paper accepted ※ 17 August 2021 issue date ※ 29 August 2021
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MOPAB138	Dielectric Wakefield Acceleration with a Laser Injected Witness Beam	wakefield, laser, cathode, simulation	481
	G. Andonian, T.J. Campese RadiaBeam, Santa Monica, California, USA N.M. Cook RadiaSoft LLC, Boulder, Colorado, USA D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA W.J. Lynn, N. Majernik, J.B. Rosenzweig, V.S. Yu UCLA, Los Angeles, California, USA
	Funding: Work supported by DOE grant DE-SC0017690 The plasma photocathode concept, whereby a two-species gas mixture is used to generate a beam -driven accelerating wakefield and a laser-ionized generation of a witness beam, was recently experimentally demonstrated. In a variation of this concept, a beam-driven dielectric wakefield accelerator is employed, filled with a neutral gas for laser-ionization and creation of a witness beam. The dielectric wakefields, in the terahertz regime, provide comparatively modest timing requirements for the injection phase of the witness beam. In this paper, we provide an update on the progress of the experimental realization of the hybrid dielectric wakefield accelerator with laser injected witness beam at the Argonne Wakefield Accelerator (AWA), including engineering considerations for gas delivery, and preliminary simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB138
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021
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MOPAB139	High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM	electron, focusing, quadrupole, target	485
	G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas RadiaBeam, Marina del Rey, California, USA M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu BNL, Upton, New York, USA C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA
	Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139
About •	paper received ※ 26 May 2021 paper accepted ※ 28 May 2021 issue date ※ 18 August 2021
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MOPAB148	Liénard-Wiechert Numerical Radiation Modeling for Plasma Acceleration Experiments at FACET-II	radiation, plasma, betatron, acceleration	517
	M. Yadav, G. Andonian, C.E. Hansel, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams, Y. Zhuang UCLA, Los Angeles, California, USA G. Andonian RadiaBeam, Marina del Rey, California, USA O. Apsimon, A. Perera, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom O. Apsimon, A. Perera, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was supported by DE-SC0009914 (UCLA) and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. Future plasma acceleration experiments at FACET-II will measure betatron radiation in order to provide single-shot non-destructive beam diagnostics. We discuss three models for betatron radiation: a new idealized particle tracking code with Liénard-Wiechert radiation, a Quasi-Static Particle-in-Cell (PIC) code with Liénard-Wiechert radiation, and a full PIC code with radiation computed via a Monte-Carlo QED Method. Predictions of the three models for the E-310 experiment are presented and compared. Finally, we discuss beam parameter reconstruction from the double differential radiation spectrum.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB148
About •	paper received ※ 24 May 2021 paper accepted ※ 01 June 2021 issue date ※ 17 August 2021
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MOPAB152	High Power Tests of Brazeless Accelerating Structures	GUI, simulation, wakefield, target	532
	S.P. Antipov, P.V. Avrakhov, C.-J. Jing, S.V. Kuzikov Euclid TechLabs, Solon, Ohio, USA V.A. Dolgashev SLAC, Menlo Park, California, USA D.S. Doran, W. Liu, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: DOE SBIR Grant #DE-SC0017749 A typical accelerating structure is a set of copper resonators brazed together. This multi step process is expensive and time consuming. In an effort to optimize production process for rapid prototyping and overall reduction of accelerator cost we developed a split block brazeless accelerating structure. In such structure the vacuum is sealed by the use of knife edges, similar to an industry standard conflat technology. In this paper we present high power tests of several different brazeless structures. First, an inexpensive 1 MeV accelerator powered by radar magnetron. Second, a high gradient power extractor tested at Argonne Wakefield Accelerator Facility. In this experiment a high charge electron beam generated a 180 MW peak power pulse. Finally, we report on high power testing of a brazeless x-band accelerating structure at SLAC.
	Poster MOPAB152 [0.783 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB152
About •	paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 31 August 2021
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MOPAB162	The First Trial of XY-Coupled Beam Phase Space Matching for Three-Dimensional Spiral Injection	injection, coupling, site, solenoid	553
	M.A. Rehman, K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa, N. Saito, K. Sasaki KEK, Ibaraki, Japan H. Hirayama, H. Iinuma, K. Oda Ibaraki University, Ibaraki, Japan R. Matsushita The University of Tokyo, Graduate School of Science, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: Work supported by "Grant in Aid" for Scientific Research, JSPS (KAKENHI# 26287055, KAKENHI#19H00673) The most recent measurement of muon g-2 results in a 3.8σ discrepancy with the equally precise theoretical prediction. The J-PARC muon g-2/EDM experiment (E34) is in preparation to decipher this discrepancy and unravel the new physics beyond the standard model. The precision goal for g-2 is 0.1 ppm. To achieve this precision goal a novel 3-D spiral injection scheme has been devised to inject and store the beam into a small diameter MRI-type storage magnet for E34. The new injection scheme features smooth injection with high storage efficiency for the compact magnet. However, the spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) at KEK Tsukuba Campus is underway to establish this injection scheme. Due to the axial symmetric field of the solenoid magnet, a strongly XY-coupled beam is required. To produce the required phase space for the solenoid-type storage magnet, a beam transport line consisting of three rotatable quadrupole magnets has been designed and built for SITE. The vertical beam size reduction by means of phase space matching and other geometrical information has been successfully measured by the wire scanners.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB162
About •	paper received ※ 20 May 2021 paper accepted ※ 28 May 2021 issue date ※ 01 September 2021
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MOPAB168	Nanoplasmonic Accelerators Towards Tens of TeraVolts per Meter Gradients Using Nanomaterials	electron, plasma, wakefield, focusing	574
	A.A. Sahai, M. Golkowski, V. Harid CU Denver, Denver, Colorado, USA C. Joshi UCLA, Los Angeles, California, USA T.C. Katsouleas Duke ECE, Durham, North Carolina, USA A. Latina, F. Zimmermann CERN, Geneva, Switzerland J. Resta-López Cockcroft Institute, Warrington, Cheshire, United Kingdom P. Taborek UCI, Irvine, California, USA A.G.R. Thomas University of Michigan, Ann Arbor, Michigan, USA
	Funding: University of Colorado Denver Ultra-high gradients which are critical for future advances in high-energy physics, have so far relied on plasma and dielectric accelerating structures. While bulk crystals were predicted to offer unparalleled TV/m gradients that are at least two orders of magnitude higher than gaseous plasmas, crystal-based acceleration has not been realized in practice. We have developed the concept of nanoplasmonic crunch-in surface modes which utilizes the tunability of collective oscillations in nanomaterials to open up unprecedented tens of TV/m gradients. Particle beams interacting with nanomaterials that have vacuum-like core regions, experience minimal disruptive effects such as filamentation and collisions, while the beam-driven crunch-in modes sustain tens of TV/m gradients. Moreover, as the effective apertures for transverse and longitudinal crunch-in wakes are different, the limitation of traditional scaling of structure wakefields to smaller dimensions is significantly relaxed. The SLAC FACET-II experiment of the nano2WA collaboration will utilize ultra-short, high-current electron beams to excite nonlinear plasmonic modes and demonstrate this possibility. * doi:10.1109/ACCESS.2021.3070798 doi:10.1142/S0217751X19430097 * indico.fnal.gov/event/19478/contributions/52561 **** indico.cern.ch/event/867535/contributions/3716404
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB168
About •	paper received ※ 11 May 2021 paper accepted ※ 08 June 2021 issue date ※ 20 August 2021
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MOPAB169	Generating 510 MW of X-Band Power for Structure-Based Wakefield Acceleration Using a Metamaterial-Based Power Extractor	wakefield, acceleration, electron, simulation	578
	J.F. Picard, I. Mastovsky, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA M.E. Conde, D.S. Doran, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid TechLabs, Solon, Ohio, USA X. Lu Northern Illinois University, DeKalb, Illinois, USA
	Funding: Research sponsored under Award No. DE-SC0015566 by U.S. Department of Energy, Office of Science, Office of High Energy Physics and Contract No. DE-AC02-06CH11357 by the Office of Science. We present our recent results generating 510 MW of power at 11.7 GHz using a metamaterial-based metallic power-extractor for application in structure-based wakefield acceleration (SWFA). SWFA is a novel acceleration scheme in which high-charge electron bunches are passed through a power extractor structure to produce a high-intensity wakefield. This wakefield can then be used to accelerate a witness bunch in the same beamline or passed to a separate acceleration beamline. MIT’s approach uses a specialized metamaterial for the power extractor design. By using a metamaterial, we can overcome some of the challenges faced by other SWFA techniques. Here, we discuss the Stage 3 experiment. The Stage 1 and Stage 2 experiments successfully demonstrated the functionality of the metamaterial approach by generating high power RF pulses using the 65 MeV electron beam at the Argonne Wakefield Accelerator (AWA) facility. The 510 MW result from Stage 3 experiment is the highest power generated to-date for SWFA at AWA, and was enable by significant design improvements, including an all-copper structure, fully-symmetric coupler design, and breakdown risk-reduction treatment.
	Poster MOPAB169 [8.882 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB169
About •	paper received ※ 08 May 2021 paper accepted ※ 16 July 2021 issue date ※ 25 August 2021
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MOPAB173	Physics Program and Experimental for AWAKE Run 2	plasma, electron, wakefield, proton	586
	P. Muggli MPI, Muenchen, Germany
	Run 1 experimental results demonstrate many characteristics of the self-modulation (SM) in plasma of a long, 400GeV SPS proton bunch. Externally injected, 19MeV electrons were accelerated to 2GeV. Based on these results, we are assembling a physics and experiment program aiming at producing a multi-GeV electron bunch with emittance and energy spread sufficiently low for possible early applications to high-energy physics experiments. Plans include two plasmas, the first for SM, the second for acceleration, and of scalable length, separated by an injection region. The first plasma includes a density step to maintain large-amplitude wakefields after saturation of the SM process. Seeding of the SM process may be obtained from an electron bunch. The 150MeV witness electron bunch from an S-band gun, X-band linac has parameters that produce plasma electron blow out and loading of the wakefields in order to minimize final energy spread and emittance*. We are studying the possibility of using a helicon plasma source for the accelerator, a source that can in principle be very long (100s of m). AWAKE, PRL 122, 054802 (2019), Turner, PRL 122, 054801 (2019), Turner, PRAB 23, 081302, (2020), Braunmueller PRL 125, 264801 (2020) AWAKE, Nature 561, 363 (2018) *Olsen, PRAB 21, 011301 (2018)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB173
About •	paper received ※ 18 May 2021 paper accepted ※ 28 May 2021 issue date ※ 02 September 2021
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MOPAB177	ELENA Commissioning and Status	proton, antiproton, MMI, electron	598
	C. Carli, M.E. Angoletta, W. Bartmann, L. Bojtár, F. Butin, B. Dupuy, Y. Dutheil, M.A. Fraser, P. Freyermuth, D. Gamba, L.V. Jørgensen, B. Lefort, O. Marqversen, M. McLean, S. Ogur, S. Pasinelli, L. Ponce, G. Tranquille CERN, Geneva, Switzerland
	The Extra Low ENergy Antiproton ring ELENA is a small synchrotron recently constructed and commissioned to decelerate antiprotons injected from the Antiproton Decelerator AD with a kinetic energy of 5.3 MeV down to 100 keV. Controlled deceleration in the synchrotron, equipped with an electron cooler to reduce losses and generate dense bunches, allows the experiments, typically capturing the antiprotons in traps and manipulating them further, to improve the trapping efficiency by one to two orders of magnitude. During 2018, bunches with an energy of 100 keV with parameters close to nominal have been demonstrated, and first beams have been provided to an experiment in a new experimental zone. The magnetic transfer lines from the AD to the experiments have been replaced by electrostatic lines from ELENA. Commissioning of the new transfer lines and, in parallel, studies to better understand the ring with H⁻ beams from a dedicated source, have started in autumn 2020. The first 100 keV antiproton physics run using ELENA will start in late summer 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB177
About •	paper received ※ 18 May 2021 paper accepted ※ 14 June 2021 issue date ※ 23 August 2021
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MOPAB179	Simulations of AGS Boosters Imperfection Resonances for Protons and Helions	resonance, proton, simulation, quadrupole	606
	K. Hock, H. Huang, F. Méot, N. Tsoupas BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. As part of the effort to increase the polarization of the proton beam for the physics experiments at RHIC, a scan of orbit harmonic corrector strengths is performed in the Booster to ensure polarization transmission through the \|G gamma\|=3 and 4 imperfection resonances is optimized. These harmonic scans have been simulated using quadrupole alignment data and accurately match experimental data. The method used to simulate polarized protons is extended to polarized helions for crossing the \|G gamma\|=5 through \|G gamma\|=10 imperfection resonances and used to determine the corrector strength required to cross each resonance.
	Poster MOPAB179 [0.437 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB179
About •	paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 02 September 2021
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MOPAB189	Beam Commissioning of XiPAF Synchrotron	extraction, synchrotron, injection, MMI	639
	H.J. Yao, X. Guan, Y. Li, X.Y. Liu, M.W. Wang, X.W. Wang, Y. Yang, W.B. Ye, H.J. Zeng, S.X. Zheng TUB, Beijing, People’s Republic of China W.L. Liu, D. Wang, Z.M. Wang NINT, Shannxi, People’s Republic of China
	XiPAF (Xi’an 200MeV Proton Application Facility) is a project to fulfill the need for the experimental simulation of the space radiation environment. It comprises a 7 MeV H⁻ linac, a 60-230 MeV proton synchrotron, and experimental stations. The Installation of the synchrotron, beamline and one experimental station were completed at the end of December 2019, and commissioning has just begun. Circulating beam around the synchrotron was observed on the first day of operation, and now 10-200 MeV proton beam directly extracted from the synchrotron had been transported to the experimental station for user experiments. The results of the commissioning and data analysis are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB189
About •	paper received ※ 18 May 2021 paper accepted ※ 21 May 2021 issue date ※ 17 August 2021
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MOPAB194	First 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac rf Cavities	cavity, vacuum, cyclotron, linac	654
	H. Hähnel, U. Ratzinger IAP, Frankfurt am Main, Germany
	Additive manufacturing (or "3D printing") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. As technology is evolving, the quality and accuracy of parts manufactured this way is ever improving. Especially interesting for the world of particle accelerators is the process of 3D printing of stainless steel (and copper) parts. We present the first fully functional IH-type drift tube structure manufactured by metal 3D printing. A 433 MHz prototype cavity has been constructed to act as a proof-of-concept for the technology. The cavity is designed to be UHV capable and includes cooling channels reaching into the stems of the DTL structure. We present the first experimental results for this prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB194
About •	paper received ※ 18 May 2021 paper accepted ※ 01 June 2021 issue date ※ 02 September 2021
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MOPAB195	Development of a Disk-and-Washer Cavity for the J-PARC Muon g-2/EDM Experiment	cavity, linac, quadrupole, coupling	658
	Y. Takeuchi, J. Tojo Kyushu University, Fukuoka, Japan E. Cicek, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan R. Kitamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue, K. Sumi, M. Yotsuzuka Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	At J-PARC, an experiment using muons accelerated by a linac is planned to measure the anomalous magnetic moment of muons and to search for the electric dipole moment. A 1296 MHz disk and washer (DAW) coupled cavity linac (CCL) is being developed for use in the middle beta section of the muon linac. The DAW CCL consists of 14 tanks with 11 cells each. All tanks are connected by bridge couplers and electromagnetic quadrupole doublets for focusing are installed in each bridge coupler. The basic design of the DAW cavity has already been completed, and now detailed cavity design studies and manufacturing process studies are underway. In this poster, we will report about these studies and the preparation status of manufacturing the DAW cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB195
About •	paper received ※ 20 May 2021 paper accepted ※ 01 June 2021 issue date ※ 23 August 2021
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MOPAB217	A Storage Ring for MESA	target, optics, simulation, operation	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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MOPAB221	Developments of a Pulse Kicker System for the Three-Dimensional Spiral Beam Injection of the J-PARC Muon g-2/EDM Experiment	kicker, injection, power-supply, solenoid	726
	K. Oda, H. Hirayama, H. Iinuma, Y. Sato, M. Sugita Ibaraki University, Ibaraki, Japan M. Abe, K. Furukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki KEK, Ibaraki, Japan R. Matsushita The University of Tokyo, Graduate School of Science, Tokyo, Japan
	The J-PARC muon g-2/EDM experiment aims to perform ultra-precise measurements of anomalous magnetic moments (g-2) and electric dipole moments (EDM) from the spin precession of muons in a precise magnetic field and to explore new physics beyond the Standard Model. On experimental requirements, the beam must be stored in a compact storage orbit with a diameter of 66 cm, which is about 1/20th smaller than that of the previous experiment. To be realized, we adopt an unprecedented injection technique called the three-dimensional spiral injection scheme. In this scheme, the beam is injected from upward of the solenoidal storage magnet. The vertical beam motion along the solenoid axis is controlled by a few 100 ns pulse kicker. Once the beam is guided into the center fiducial storage volume, the muon beam is stored by the weak focusing magnetic field. Therefore, stable and accurate control of the pulse kicker is one of the major technical challenges to realize the ultra-precise measurement of the muon spin precession. In this presentation, we discuss the performance of the prototype pulse kicker device and future plan for installation of it to our test bench with an electron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB221
About •	paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 15 August 2021
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MOPAB241	Design of the Proton and Electron Transfer Lines for AWAKE Run 2c	plasma, electron, proton, acceleration	778
	R.L. Ramjiawan JAI, Oxford, United Kingdom S. Döbert, E. Gschwendtner, P. Muggli, F.M. Velotti, L. Verra CERN, Meyrin, Switzerland J.P. Farmer MPI-P, München, Germany P. Muggli MPI, Muenchen, Germany
	The AWAKE Run 1 experiment achieved electron acceleration to 2 GeV using plasma wakefield acceleration driven by 400 GeV, self-modulated proton bunches from the CERN SPS. The Run 2c phase of the experiment aims to build on these results by demonstrating acceleration to ~10 GeV while preserving the quality of the accelerated electron beam. To realize this, there will be an additional plasma cell, to separate the proton bunch self-modulation and the electron acceleration. A new 150 MeV beamline is required to transport and focus the witness electron beam to a beam size of several microns at the injection point. This specification is designed to preserve the beam emittance during acceleration, also requiring micron-level stability between the driver and witness beams. To facilitate these changes, the Run 1 proton transfer line will be reconfigured to shift the first plasma cell 40 m downstream. The Run 1 electron beamline will be adapted and used to inject electron bunches into the first plasma cell to seed the proton bunch self-modulation. Proposed adjustments to the proton transfer line and studies for the designs of the two electron transfer lines are detailed in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB241
About •	paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 17 August 2021
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MOPAB256	Development of Pulsed Beam System for the Three Dimensional Spiral Injection Scheme in the J-PARC muon g-2/EDM Experiment	injection, kicker, power-supply, controls	809
	R. Matsushita The University of Tokyo, Graduate School of Science, Tokyo, Japan M. Abe, K. Hurukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki KEK, Ibaraki, Japan H. Hirayama, H. Iinuma, K. Oda, Y. Sato, M. Sugita Ibaraki University, Ibaraki, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Takayanagi JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC muon g-2/EDM experiment aims to measure the anomalous magnetic moment(g-2) and electric dipole moment(EDM) of the muon with higher precision than the previous BNL E821 experiment. A brand-new three-dimensional spiral injection scheme is employed to inject and store muon beam into a 66 cm diameter of storage magnet. Feasibility studies are ongoing by use of 80 keV electron beam at KEK test bench, to develop skills on control transverse beam motion; so-called X-Y coupling, with DC beam. As a next step, towards store the beam by use of a kicker system, a pulsed beam should be generated from the DC beam with an intended time structure to meet a pulse kicker’s duration time, without changing transverse phase space characteristics. In this presentation, the development of a beam chopper device and the evaluation of pulse beam profile are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB256
About •	paper received ※ 20 May 2021 paper accepted ※ 15 June 2021 issue date ※ 16 August 2021
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MOPAB267	End to End Simulations of Antiproton Transport and Degradation	simulation, proton, antiproton, electron	847
	S. Padden, E. Kukstas, P. Pusa, V. Rodin, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom K. Nordlund HIP, University of Helsinki, Finland V. Rodin, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The ELENA ring decelerates anti-protons to 100 keV down from 5.3 MeV with transport to experiments handled by electrostatic transfer lines. Even at 100 keV antiprotons are still too high in energy for direct injection into an ion trap, and this is why degrader foils are used to further lower the energy. This contribution presents full end-to-end simulations from the point of extraction until passing through the foil using realistic beam transport simulations coupled with accurate simulations of degrader foils via the use of density functional theory and molecular dynamics. Particles are tracked from the point of extraction until their injection into the trap with full physical modeling at all time steps. The results of this study provide a versatile platform for the optimization of low energy ion experiments towards specific targets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB267
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 24 August 2021
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MOPAB273	Nonlinear Coupling Resonances in X-Y Coupled Betatron Oscillations Near the Main Coupling Resonance in VEPP-2000 Collider	resonance, betatron, coupling, collider	863
	S.A. Kladov, E. Perevedentsev BINP SB RAS, Novosibirsk, Russia S.A. Kladov, E. Perevedentsev NSU, Novosibirsk, Russia
	In the vicinity of the linear coupling resonance where the working point of the collider is positioned, we study the effect of nonlinear coupling resonances on the single-particle phase space, beam sizes and the waveform of coherent beam motion. The latter is interesting for diagnostics of the nonlinear dynamics.
	Poster MOPAB273 [1.142 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB273
About •	paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 21 August 2021
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MOPAB280	Split Ring Resonator Experiment - Simulation Results	simulation, laser, electron, solenoid	888
	J. Schäfer, B. Härer, A. Malygin, A.-S. Müller, M. Nabinger, M.J. Nasse, T. Schmelzer, M. Schuh, T. Windbichler KIT, Karlsruhe, Germany
	Funding: Supported by "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)" and European Union’s Horizon 2020 Research and Innovation programme. FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D. An example for a new accelerator diagnostics tool currently studied at FLUTE is the split-ring-resonator (SRR) experiment, which aims to measure the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Particles passing through the SRR gap are time-dependently deflected in the vertical plane, which allows a vertical streaking of an electron bunch. This principle allows a diagnosis of the longitudinal bunch profile in the femtosecond time domain and will be tested at FLUTE. This contribution presents an overview of the SRR experiment and the results of various tracking simulations for different scenarios as a function of laser pulse length and bunch charge. Based on these results possible working points for the experiments at FLUTE will be proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB280
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021
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MOPAB281	Research on Resolution Evaluation of Stripline BPM at SXFEL-UF	FEL, network, electron, linac	892
	B. Gao, J. Chen, Y.B. Leng SSRF, Shanghai, People’s Republic of China
	48 stripline BPMs are installed in the injection section and linear acceleration section of Shanghai X-ray Free Electron Laser (SXFEL) for electron beam position measurement. These two sections require resolution of 20 µm@100pC. Resolution evaluation is an important step in BPM installation and commissioning. This paper presents BPM resolution evaluation methods based on correlation analysis. Experimental methods, data processing and result analysis will be discussed
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB281
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 02 September 2021
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MOPAB282	Development of a Multi-Camera System for Non-Invasive Intense Ion Beam Investigations	diagnostics, ion-source, solenoid, vacuum	895
	A. Ateş, H. Hähnel, U. Ratzinger, K. Volk, C. Wagner IAP, Frankfurt am Main, Germany
	The continued popularity of miniaturized cameras integrated into smartphones is leading to further research for more advanced CMOS camera sensors. This made CMOS technology even superior to scientific CCD cameras. Due to the lower power consumption and high flexibility, a multicamera system can be developed more effectively. At the Institute of Applied Physics at Goethe University Frankfurt (IAP) a prototype of a beam induced rest gas fluorescence monitor (BIF) was developed and tested successfully. The BIF consists of x and y single board cameras integrated into the vacuum chamber. A multi-camera system was installed in the LEBT area of the FRANZ project at the IAP within the first diagnostic chamber. This system consists of six cameras. With this equipment it is possible to investigate the beam along a 484 mm path in x and y direction. The developments on the reconstruction and image processing methods are in progress.
	Poster MOPAB282 [1.139 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB282
About •	paper received ※ 12 May 2021 paper accepted ※ 08 June 2021 issue date ※ 24 August 2021
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MOPAB286	Towards a Data Science Enabled MeV Ultrafast Electron Diffraction System	electron, network, real-time, laser	906
	M.A. Fazio, S. Biedron, M. Martínez-Ramón, D.J. Monk, S.I. Sosa Guitron UNM-ECE, Albuquerque, USA M. Babzien, K.A. Brown, M.G. Fedurin, J.J. Li, M.A. Palmer, J. Tao BNL, Upton, New York, USA S. Biedron, T. Talbott UNM-ME, Albuquerque, New Mexico, USA J. Chen, A.J. Hurd, N.A. Moody, R. Prasankumar, C. Sweeney LANL, Los Alamos, New Mexico, USA D. Martin, M.E. Papka ANL, Lemont, Illinois, USA
	Funding: US DOE, SC, BES, MSE, award DE-SC0021365 and DOE NNSA award 89233218CNA000001 through DOE’s EPSCoR program in Office of BES with resources of DOE SC User Facilities BNL’s ATF and ALCF. A MeV ultrafast electron diffraction (MUED) instrument is a unique characterization technique to study ultrafast processes in materials by a pump-probe technique. This relatively young technology can be advanced further into a turn-key instrument by using data science and artificial intelligence (AI) mechanisms in conjunctions with high-performance computing. This can facilitate automated operation, data acquisition and real time or near- real time processing. AI based system controls can provide real time feedback on the electron beam which is currently not possible due to the use of destructive diagnostics. Deep learning can be applied to the MUED diffraction patterns to recover valuable information on subtle lattice variations that can lead to a greater understanding of a wide range of material systems. A data science enabled MUED facility will also facilitate the application of this technique, expand its user base, and provide a fully automated state-of-the-art instrument. We will discuss the progress made on the MUED instrument in the Accelerator Test Facility of Brookhaven National Laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB286
About •	paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 25 August 2021
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MOPAB287	The Development of Single Pulse High Dynamic Range BPM Signal Detector Design at AWA	detector, electron, pick-up, electronics	909
	E.M. Siebert, S. Baturin Northern Illinois University, DeKalb, Illinois, USA D.S. Doran, G. Ha, W. Liu, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: the US Department of Energy, Office of Science Single pulse high dynamic range BPM signal detector has been on the most wanted list of Argonne Wakefield Accelerator (AWA) Test Facility for many years. Unique capabilities of AWA beamline require BPM instrumentation with an unprecedented dynamic range, thus cost effective solution could be challenging to design and prototype. Our most recent design, and the results of our quest for a solution, are shared in this paper.
	Poster MOPAB287 [1.372 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB287
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 13 August 2021
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MOPAB293	Electro-Optical Diagnostics at KARA and FLUTE - Results and Prospects	diagnostics, electron, laser, storage-ring	927
	G. Niehues, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, M.M. Patil, R. Ruprecht, M. Schuh, M. Weber, C. Widmann KIT, Karlsruhe, Germany
	Funding: S.F. was funded by BMBF contract No. 05K16VKA, C. W. by BMBF contract number 05K19VKD. G.N. and E.B. acknowledge support by the Helmholtz President’s strategic fund IVF "Plasma Accelerators". Electro-optical (EO) methods are nowadays well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). These measurements facilitate studies of physical conditions to provide, at the end, intense and stable CSR in the THz range. At KIT, we also operate FLUTE (Ferninfrarot Linac- und Test-Experiment), a new compact versatile linear accelerator as a test facility for novel techniques and diagnostics. There, EO diagnostics will be implemented to open up possibilities to evaluate and compare new techniques for longitudinal bunch diagnostics. In this contribution, we will give an overview of results achieved, the current status of the EO diagnostic setups at KARA and FLUTE and discuss future prospects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB293
About •	paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 17 August 2021
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MOPAB300	Description of the Beam Diagnostics Systems for the SOCIT, SODIT and SODIB Applied Research Stations Based on the NICA Accelerator Complex	detector, controls, diagnostics, radiation	946
	A. Slivin, A. Agapov, A.A. Baldin, A.V. Butenko, G.A. Filatov, K.N. Shipulin, E. Syresin, G.N. Timoshenko, A. Tuzikov JINR, Dubna, Moscow Region, Russia D.V. Bobrovskiy, A.I. Chumakov, S. Soloviev MEPhI, Moscow, Russia I.L. Glebov, V.A. Luzanov GIRO-PROM, Dubna, Moscow Region, Russia A.S. Kubankin BelSU, Belgorod, Russia T. Kulevoy, Y.E. Titarenko ITEP, Moscow, Russia
	Within the framework of the NICA project an Innovation Block is being constructed. It includes an applied research station for microchips with a package for Single Event Effects (SEE) testing (energy range of 150-500 MeV/n, the SODIT station), an applied research station for testing of decapsulated microchips (ion energy up to 3,2 MeV/n, the SOCIT station), and an applied research station for space radiobiological research and modelling of influence of heavy charged particles on cognitive functions of the brain of small laboratory animals and primates (energy range 500-1000 MeV/n, the SODIB station). The systems for diagnostics and control of the beam characteristics during the certification and adjustment as well as the systems for online diagnostics and control of the beam characteristics of the SOCIT, SODIT and SODIB applied research stations are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB300
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 23 August 2021
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MOPAB302	Characterization of the Full Transverse Phase Space of Electron Bunches at ARES	simulation, electron, quadrupole, linac	952
	S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, H. Dinter, W. Kuropka, F. Mayet, T. Vinatier DESY, Hamburg, Germany R.W. Aßmann INFN/LNF, Frascati, Italy S. Jaster-Merz University of Hamburg, Hamburg, Germany
	The ARES linear accelerator at the SINBAD facility (DESY) is dedicated to perform accelerator R&D studies with sub-fs short electron bunches to test novel acceleration techniques and diagnostics devices. Currently, the commissioning of the linac is ongoing and first experiments are being performed. For this, the knowledge of the full phase space of the particle beams is of high interest to, for example, optimize the accelerator performance and identify possible errors in the beam line. Tomographic methods can be used to gain insight into the full 4D transverse phase space and its correlations. Here, simulation results and first experimental preparations of a 4D transverse phase-space tomography of electron bunches at ARES are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB302
About •	paper received ※ 17 May 2021 paper accepted ※ 16 June 2021 issue date ※ 30 August 2021
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MOPAB310	Vertical Phase Space Measurement Progress at Canadian Light Source	electron, emittance, lattice, synchrotron	963
	Y. Yousefi Sigari, D. Bertwistle, M.J. Boland CLS, Saskatoon, Saskatchewan, Canada M.J. Boland University of Saskatchewan, Saskatoon, Canada
	A key feature of third-generation light sources is their small vertical opening angle, which is difficult to measure experimentally. To reconstruct the vertical phase space, one can scan the beam’s position using X-ray synchrotron radiation (XSR) and a pinhole camera. The XSR diagnostic beamline, operational in the wavelength region of 0.05 - 0.15 nm, in Canadian Light Source (CLS) is qualified to measure the beam position with X-ray radiation. Using the corrector magnets in CLS lattice made of 12 identical double-bend achromats (DBA) cells, vertical iterations can be executed parallel to the beam’s original orbit. The outcomes of this experiment are: 1) the vertical beam positions that are monitored by BPMs, and 2) the X-ray image of the beam that is projected through the pinhole. The bumps were simulated using Matlab Middle Layer (MML) for Accelerator control systems to get an insight of the source point’s position in the XSR’s bending magnet. The simulation shows the position of the source point depends on which corrector sets are chosen.
	Poster MOPAB310 [0.328 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB310
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 13 August 2021
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MOPAB314	Surrogate Modeling for MUED with Neural Networks	electron, gun, network, operation	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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MOPAB318	Beam Characterization of Five Electrode ECR Ion Source	emittance, ECR, ECRIS, plasma	980
	H.M. Kewlani, S. Gharat, S. Krishnagopal, J.V. Mathew, S.V.L.S. Rao BARC, Mumbai, India B. Dikshit, H.M. Kewlani, S. Krishnagopal Homi Bhbha National Institute (HBNI), DAE, Mumbai, India
	A five electrode ECR Ion Source (ECRIS) was developed for the Low Energy High-Intensity Proton Accelerator (LEHIPA) at BARC. The ECRIS is operated at the energy of 50 keV with a beam current of 20 mA. The ECRIS characterization is done for the beam current, beam emittance, and proton fraction in continuous and pulse beam operation. The pulsed beam operation of the ion source starting from 500 µs to 200 ms of pulse on time with a repetition rate of 1 to 10 Hz. The transverse beam emittance measurement is done by using an Allison scanner. The beam emittance characterization experiments are conducted by varying applied microwave power to the plasma, operating gas pressure of plasma and puller voltage. The measured beam emittance is in the range of 0.3 pi.mm. mrad to 0.4 pi.mm. mrad for 50 keV beam. In this paper beam emittance experiment setup and results are discussed.
	Poster MOPAB318 [2.496 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB318
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 16 August 2021
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MOPAB320	The CMS ECAL Enfourneur: A Gigantic Machine with a Soft Touch	operation, controls, alignment, insertion	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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MOPAB325	Development of Bunch Width Monitor with High Time Resolution for Low Emittance Muon Beam in the J-PARC Muon g-2 / EDM Experiment	emittance, acceleration, linac, laser	1004
	M. Yotsuzuka, T. Iijima, K. Inami, Y. Sue, K. Sumi Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan Y. Kondo JAEA, Ibaraki-ken, Japan T. Mibe KEK, Tsukuba, Japan Y. Nakazawa Ibaraki University, Ibaraki, Japan M. Otani, N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Takeuchi Kyushu University, Fukuoka, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	The J-PARC muon g-2/EDM experiment plans to measure the muon anomalous magnetic moment and electric dipole moment sensitive to new physics with high precision. This experiment uses a novel method using the low-emittance muon beam achieved by cooling and re-acceleration. In the muon linac consisting of four different accelerating cavities, the main cause of the emittance growth is the beam mismatch between the different cavities. Especially for the cavity in the low-beta section (ß=0.08-0.27), the longitudinal acceptance is narrow and beam mismatch has a significant impact. In order to perform beam matching in the low-beta cavity, a new beam monitor that can measure the low-emittance muon beam with high time resolution is required. Therefore, we developed a bunch width monitor (BWM) using a microchannel plate. The time resolution of the BWM was measured to be 40 picoseconds on the test bench using a picosecond pulse laser. It means that the BWM is possible to perform diagnosis with a phase accuracy of 1% for the acceleration phase of 324 MHz. We also evaluated factors that limit the current time resolution. In this presentation, the results of an evaluation of the BWM are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB325
About •	paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 10 August 2021
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MOPAB340	Experimental Tests with the First Segment of ESS-Bilbao RFQ Linac	rfq, vacuum, simulation, operation	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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MOPAB346	Broadband Frequency Electromagnetic Characterisation of Coating Materials	GUI, electron, vacuum, site	1076
	A. Passarelli, C. Koral, M.R. Masullo INFN-Napoli, Napoli, Italy A. Andreone Naples University Federico II, Napoli, Italy M. De Stefano University of Naples, Naples, Italy V.G. Vaccaro Naples University Federico II and INFN, Napoli, Italy
	In the new generation of particle accelerators and storage rings, collective effects have to be carefully analyzed. In particular, the finite conductivity of the beam pipe walls is a major source of impedance and instabilities. A reliable electromagnetic (EM) characterisation of different coating materials is required up to hundreds of GHz due to very short bunches. We propose two different measurement techniques for an extended frequency characterization: (i) a THz time domain setup based on the signal transmission response of a tailored waveguide to infer the coating EM properties from 100 to 300 GHz or even further.. This technique has been tested both on NEG and amorphous Carbon films. (ii) a resonant method, based on dielectric cavities, to evaluate the surface resistance Rs of thin conducting samples at low (GHz) frequencies*. Due to its high sensitivity, Rs values can be obtained for very thin (nanometric) coatings or for copper samples with a laser treated surface, since they have an expected conductivity very close to bulk copper. A. Passarelli et al., Phys. Rev. Accel. Beams, v.21, p.103101, 2018 A. Passarelli et al., Cond. Matter, v.5, p.9, 2020 *A. Andreone et al., Applied Physics Letters, v.91, n.7, p.072512, 2007
	Poster MOPAB346 [2.613 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB346
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 26 August 2021
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MOPAB361	Threshold in Filling Failure of RF Cavity Caused by Beam Loading in Multipactor	multipactoring, cavity, simulation, electron	1122
	J. Pang USTC/NSRL, Hefei, Anhui, People’s Republic of China Y. Dong Institute of Applied Physics and Computational Mathematics, People’s Republic of China Y. Du Institute of Fluid Physics,, China Academy of Engineering Physics, Mianyang, People’s Republic of China
	Funding: NSFC A pulsed RF cavity would be heavily detuned caused by beam loading of multipactor current in the RF filling process. Multipactor zone would be expended by several times than that in static states with assumptions of fixed voltage and no beam loading. The dynamic of multipactor in the RF filling process was simulated by coupling with parameters of external circuit with the developed simulation code, and test in experiments with a parallel-plate resonator. Threshold of RF voltage, which means the lower boundary of peak voltage of multipactor zone, had been quantified with different cavity parameters. When we increased the gap length, the measured threshold became larger due to the ionization in background gas. Then the secondary emission factor would be increased in simulation for consistence with the experiment results. Additionally, some multipactor phenomenon could not be predicted precisely because the simulation code did not take account of ionization. The hysteresis of phase and energy of ionization electrons would be a new driving factor for the growth of multipactor in certain conditions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB361
About •	paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 10 August 2021
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MOPAB362	Atomistic Modeling of the Coupling Between Electric Fields and Bulk Plastic Deformation in Rf Structures	simulation, coupling, feedback, framework	1125
	S. Bagchi, D. Perez LANL, Los Alamos, New Mexico, USA
	Funding: LANL-LDRD A notable bottleneck in achieving high-gradient RF technology is dictated by the onset of RF breakdown. While bulk mechanical properties are known to significantly affect breakdown propensity, the underlying mechanisms coupling RF fields to bulk plastic deformation in experimentally relevant thermo-electrical loading conditions remain to be identified at the atomic scale. Here, we present results of large-scale molecular dynamics simulations (MD) to investigate possible modes of coupling. We consider the activation of Frank-Read (FR) sources, which leads to dislocation multiplication, under the action of bi-axial thermal stresses and surface electric-field. With a charge-equilibration formalism incorporated in a classical MD model, we show that a surface electric field acting on an either preexisting or dislocation-induced surface step, can generate a long-range resolved shear stress field inside the bulk of the sample. We investigate the feedback between step growth following dislocation emission and subsequent activations of FR sources and discuss the regimes of critical length-scales and densities of dislocations, where such a mechanism could promote RF breakdown precursors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB362
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 19 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, operation, 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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MOPAB383	Pressure Test for Large Grain and Fine Grain Niobium Cavities	cavity, niobium, SRF, FEM	1173
	M. Yamanaka, T. Dohmae, H. Inoue, T. Saeki, K. Umemori, Y. Watanabe, K. Yoshida KEK, Ibaraki, Japan K. Enami Tsukuba University, Ibaraki, Japan
	The pressure test was performed using a fine grain (FG) and a large grain (LG) niobium cavities. The cavity is 1.3 GHz 3-cell TESLA-like shape. The cavity was housed in a steel vessel. Water is supplied into the vessel and the cavity outside is pressurized. The applying pressure and the natural frequency of cavity were measured during the pressure test. The FG and LG cavities were deformed greatly and the pressure dropped suddenly at 3.4 MPa and 1.6 MPa, respectively. The frequency shifted up to 3.4 MHz and 1.3 MHz, respectively. There was no leak after the pressure test, so the cavity did not rupture under above pressure. The result of the pressure at LG cavity is less half than that of the FG cavity. We calculated the stress distribution in the structure by applying outer water pressure using a FEM. The maximum stress at cell when above test pressure is applied, are 146 MPa in FG and 73 MPa in LG, respectively. These stresses are similar to tensile strength of niobium specimen measure by ourselves. The result of pressure tests agrees well with the calculation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB383
About •	paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 28 August 2021
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MOPAB392	Alternative RF Tuning Methods Performed on Spoke Cavities for ESS and MYRRHA Projects	cavity, operation, target, simulation	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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MOPAB394	Preliminary BCP Flow Field Investigation by CFD Simulations and PIV in a Transparent Model of a SRF Elliptical Low Beta Cavity	cavity, simulation, SRF, laser	1204
	A. D’Ambros, M. Bertucci, A. Bosotti, A.T. Grimaldi, P. Michelato, L. Monaco, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy F. Cozzi, G. Pianello Politecnico di Milano, Milano, Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	Standard vertical Buffered Chemical Polishing (BCP) is one of the main surface treatment for Superconducting Radiofrequency (SRF) cavities. A finite element Computational Fluid Dynamic (CFD) model has been developed. Uncertainties in the solution of fluid simulations are not negligible due to the complex geometry of a SRF cavity; thus without an experimental validation, results from this type of simulations cannot be confidently used to improve the process. To this aim, an experimental study was started to investigate the fluid dynamics of the BCP process by means of Particle Image Velocimetry (PIV) technique. Similitude on Reynolds number and Refractive Index Matching (RIM) technique were also implemented to replace the dangerous BCP mixture with a glycerine-water mixture. The paper describes the preliminary results from simulations and experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB394
About •	paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 13 August 2021
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MOPAB396	Measurements of Magnetic Field Penetration in Superconducting Materials for SRF Cavities	cavity, SRF, solenoid, accelerating-gradient	1208
	I.H. Senevirathne, J.R. Delayen, A.V. Gurevich ODU, Norfolk, Virginia, USA J.R. Delayen, A-M. Valente-Feliciano JLab, Newport News, Virginia, USA
	Funding: This work is supported by NSF Grants PHY-1734075 and PHY-1416051, and DOE Award DE-SC0010081 and DE-SC0019399 Superconducting radiofrequency (SRF) cavities used in particle accelerators operate in the Meissner state. To achieve high accelerating gradients, the cavity material should stay in the Meissner state under high RF magnetic field without penetration of vortices through the cavity wall. The field onset of flux penetration into a superconductor is an important parameter of merit of alternative superconducting materials other than Nb which can enhance the performance of SRF cavities. There is a need for a simple and efficient technique to measure the onset of field penetration into a superconductor directly. We have developed a Hall probe experimental setup for the measurement of the flux penetration field through a superconducting sample placed under a small superconducting solenoid magnet which can generate magnetic fields up to 500 mT. The system has been calibrated and used to measure different bulk and thin film superconducting materials. This system can also be used to study SIS multilayer coatings that have been proposed to enhance the vortex penetration field in Nb cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB396
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021
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MOPAB401	In-Situ EXAFS Investigations of Nb-Treatments in N₂, O₂ and N₂-O₂ Mixtures at Elevated Temperatures	vacuum, site, niobium, cavity	1214
	P. Rothweiler, B. Bornmann, J. Klaes, D. Lützenkirchen-Hecht, R. Wagner University of Wuppertal, Wuppertal, Germany
	Funding: We gratefully acknowledge financial support by the German Federal Ministry of Education and Research (BMBF) under project No. 05H18PXRB1. Smooth polycrystalline Nb metal foils were treated in dilute gas atmospheres using a temperature of 900 °C. Transmission mode X-ray absorption spectroscopy (EX-AFS) at the Nb K-edge was used to investigate changes in the atomic short-range order structure of the bulk Nb-material in-situ. The experiments were performed in a dedicated high-vacuum cell that allows treatments in a dilute gas atmosphere and temperatures of up to 1200 °C. Typical treatments include (i) pre-heating at 900 °C under high-vacuum, (ii) gas exposure at the desired pressure and temperature, and (iii) cooldown to room temperature under vacuum. EXAFS data were collected during the entire procedure with a time resolution of 1 s. For the treatments in N₂ at T = 900°C, the data show subtle changes in the Nb-EXAFS, that are compatible with N-doping of the bulk Nb, and the results suggest Nb uptake on octahedral interstitial sites. However, even a small O2-partial pressure leads to distinct oxidation of the Nb. The results will be discussed in more detail in the presentation.
	Poster MOPAB401 [2.032 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB401
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 27 August 2021
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MOPAB409	FLUKA Simulations of ²²⁵Ac Production Using Electron Accelerators: Validation Through Comparison with Published Experiments	electron, target, radiation, photon	1226
	T.V. Szabo, I.C. Moraes CNPEM, Campinas, SP, Brazil F.A. Bacchim Neto LNLS, Campinas, Brazil P.V. Guillaumon USP/LAL, Sao Paulo, Brazil H.B. de Oliveira IPEN, São Paulo, Brazil
	Targeted Alpha Therapy (TAT) is an active area of study worldwide. This technique has shown a potential in nuclear medicine to treat metastatic disease by alpha particles that deposit energy in small regions nearby cancer cells. Ac-225 is an important alpha-emitting that can be used for cancer TAT. This radioisotope shows good potential for medical applications, therefore is important to study ways of increase its production and availability. One possible path for the Ac-225 product is to radiate a radium target (Ra-226) on a linear electron accelerator (LINAC). Isotope production studies could be implemented using computational tools. In this work, Monte Carlo simulations with FLUKA code were performed and compared to experimental results . We studied Ac-225 production by photonuclear reactions using a 24 MeV electron beam LINAC hitting a tungsten electron-photon converter. Different energies and geometries were also simulated to obtain optimal production conditions. The specific activity values obtained with simulations had a good agreement with published experimental results. MASLOV, O., et. al. Preparation of 225Ac by 226Ra(g, n) photonuclear reaction on an mt25 microtron. Radiochemistry
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB409
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021
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MOPAB411	Quantifying DNA Damage in Comet Assay Images Using Neural Networks	network, proton, software, radiation	1233
	S.J.K. Dhinsey, T. Greenshaw, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom J.L. Parsons Cancer Research Centre, University of Liverpool, Liverpool, United Kingdom C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was supported by the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. Proton therapy for cancer treatment is a rapidly growing field and increasing evidence suggests it induces more complex DNA damage than photon therapy. Accurate comparison between the two treatments requires quantification of the DNA damage the cause, which can be assessed using the Comet Assay. The program outlined here is based on neural network architecture and aims to speed up analysis of Comet Assay images and provide accurate, quantifiable assessment of the DNA damage levels apparent in individual cells. The Comet Assay is an established technique in which DNA fragments are spread out under the influence of an electric field, producing a comet-like object. The elongation and intensity of the comet tail (consisting of DNA fragments) indicate the level of damage incurred. Many methods to measure this damage exist, using a variety of algorithms. However, these can be time consuming, so often only a small fraction of the comets available in an image are analysed. The automatic analysis presented in this contribution aims to improve this. To supplement the training and testing of the network, a Monte Carlo model will also be presented to create simulated comet assay images.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB411
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 16 August 2021
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MOPAB414	A Novel Facility for Cancer Therapy and Biomedical Research with Heavy Ions for the South East European International Institute for Sustainable Technologies	synchrotron, extraction, injection, radiation	1244
	S. Damjanovic, P. Grübling, H. Schopper SEEIIST, Geneva, Switzerland U. Amaldi, E. Benedetto, M. Sapinski TERA, Novara, Italy E. Benedetto, G. Bisoffi, M. Dosanjh, M. Sapinski, M. Vretenar CERN, Meyrin, Switzerland G. Bisoffi INFN/LNL, Legnaro (PD), Italy S. Damjanovic, M. Durante, P. Foka, C. Graeff GSI, Darmstadt, Germany Th. Haberer HIT, Heidelberg, Germany S. Rossi CNAO Foundation, Milan, Italy H.J. Specht Universität Heidelberg, Heidelberg, Germany
	The South East European International Institute for Sustainable Technologies (SEEIIST) proposes the construction of a major joint Research Infrastructure in the region, to rebuild cooperation after the recent wars and overcome lasting consequences like technology deficits and brain drain, having at its core a facility for cancer therapy and biomedical research with heavy ions. Beams of ions like Carbon are an advanced way to irradiate tumours but more research is needed, while the higher investment costs than for other radiation treatments have so far limited the European facilities to only four. This initiative aims at being strongly innovative, beyond the existing European designs. While the initial baseline relies on a conservative warm-magnet synchrotron, superconducting magnets for an advanced version of the synchrotron and for the gantry are being developed, with a potential for reductions in size, cost, and power consumption. Both warm and superconducting designs feature high beam intensity for faster treatment, and flexible extraction for novel treatment methods. A novel injector linac has the potential for producing radioisotopes in parallel with synchrotron injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB414
About •	paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 22 August 2021
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MOPAB418	Tracking and LET Measurements with the MiniPIX-TimePIX Detector for 60 MeV Clinical Protons	detector, radiation, proton, instrumentation	1260
	J.S.L. Yap, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom N.J.S. Bal NIKHEF, Amsterdam, The Netherlands M.D. Brooke University of Oxford, Oxford, United Kingdom C. Granja, C. Oancea ADVACAM s.r.o, Prague, Czech Republic A. Kacperek The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom C.P. Welsch, J.S.L. Yap The University of Liverpool, Liverpool, United Kingdom
	Funding: EU FP7 grant agreement 215080, H₂020 Marie Sklodowska-Curie grant agreement No 675265, OMA - Optimization of Medical Accelerators and the Cockcroft Institute core grant STGA00076-01. Recent advancements in accelerator technology have led the rapid emergence of particle therapy facilities worldwide, affirming the need for enhanced characterisation methods of radiation fields and radiobiological effects. The Clatterbridge Cancer Centre, UK operates a 60 MeV proton beam to treat ocular cancers and facilitates studies into proton induced radiobiological responses. Accordingly, an indicator of radiation quality is the linear energy transfer (LET), a challenging physical quantity to measure. The MiniPIX-Timepix is a miniaturised, hybrid semiconductor pixel detector with a Timepix ASIC, enabling wide-range measurements of the deposited energy, position and direction of individual charged particles. High resolution spectrometric tracking and simultaneous energy measurements of single particles enable the beam profile, time, spatial dose mapping and LET (0.1 to >100 keV/µm) to be resolved. Measurements were performed to determine the LET spectra in silicon, at different positions along the Bragg Peak (BP). We discuss the experimental setup, preliminary results and applicability of the MiniPIX for clinical environments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB418
About •	paper received ※ 18 May 2021 paper accepted ※ 23 July 2021 issue date ※ 25 August 2021
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TUXA03	Progress in Mastering Electron Clouds at the Large Hadron Collider	simulation, electron, operation, luminosity	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, operation, 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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TUXA05	Measurements of Beam-Beam Interactions in Gear-Changing Collisions in DESIREE	collider, beam-beam-effects, HOM, framework	1283
	E.A. Nissen JLab, Newport News, Virginia, USA A. Källberg, A. Simonsson Stockholm University, Stockholm, Sweden
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript. In this work, we perform measurements on the interactions of colliding beams in a gear-changing system. Gear-changing was first demonstrated in DESIREE in May of 2020 and showed several promising avenues to measure beam-beam effects. DESIREE has a unique collision scheme where the beams are moving in the same direction, which provides for unique interactions. This experiment used a 4 on 3 gear changing system with one bucket in each ring left empty, this allows us to see the bunch profile while undergoing collisions. We then measured the bunch length over time and used a Fourier transform to extract longitudinal evolution data and compared it to baseline data of uncollided beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA05
About •	paper received ※ 21 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021
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MOXB02

First Results of the IOTA Ring Research at Fermilab

electron, optics, lattice, octupole

19

A. Valishev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, B.L. Cathey, S. Chattopadhyay, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari
Fermilab, Batavia, Illinois, USA
A. Arodzero, A.Y. Murokh, M. Ruelas
RadiaBeam, Santa Monica, California, USA
D.L. Bruhwiler, J.P. Edelen, C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA
S. Chattopadhyay, S. Szustkowski
Northern Illinois University, DeKalb, Illinois, USA
A. Halavanau, Z. Huang, V. Yakimenko
SLAC, Menlo Park, California, USA
M. Hofer
TU Vienna, Wien, Austria
M. Hofer, R. Tomás García
CERN, Geneva, Switzerland
K. Hwang, C.E. Mitchell, R.D. Ryne
LBNL, Berkeley, California, USA
K.-J. Kim
ANL, Lemont, Illinois, USA
K.-J. Kim, Y.K. Kim, N. Kuklev, I. Lobach
University of Chicago, Chicago, Illinois, USA
T.V. Shaftan
BNL, Upton, New York, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling and quantum science experiments. In this talk we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented will be the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXB02

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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MOPAB004

JSPEC - A Simulation Program for IBS and Electron Cooling

electron, simulation, emittance, scattering

49

H. Zhang, S.V. Benson, M.W. Bruker, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Intrabeam scattering is an important collective effect that can deteriorate the properties of a high-intensity beam, and electron cooling is a method to mitigate the IBS effect. JSPEC (JLab Simulation Package for Electron Cooling) is an open-source program developed at Jefferson Lab, which simulates the evolution of the ion beam under the IBS and/or the electron cooling effect. JSPEC has been benchmarked with BETACOOL and experimental data. In this report, we will introduce the features of JSPEC, including the friction force calculation, the IBS expansion rate and electron cooling rate calculation, and the beam-dynamic simulations for the electron cooling process; explain how to set up the simulations in JSPEC; and demonstrate the benchmarking results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB004

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

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MOPAB008

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

octupole, luminosity, operation, 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, operation, 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

operation, luminosity, electron, emittance

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

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

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MOPAB014

First High Spin-Flip Efficiency for High Energy Polarized Protons

polarization, resonance, dipole, proton

84

H. Huang, J. Kewisch, C. Liu, A. Marusic, W. Meng, F. Méot, P. Oddo, V. Ptitsyn, V.H. Ranjbar, T. Roser
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 order to minimize the systematic errors for the Relativistic Heavy Ion Collider (RHIC) spin physics experiments, flipping the spin of each bunch of protons during the stores is needed. Experiments done with single RF magnet at energies less than 2 GeV have demonstrated a spin-flip efficiency over 99%. At high energy colliders with Siberian snakes, a single magnet spin flipper does not work because of the large spin tune spread and the generation of multiple, overlapping resonances. Over past decade, RHIC spin flipper design has evolved and a sophisticated spin flipper, constructed of nine-dipole magnets, was developed to flip the spin in RHIC. A special optics choice was also used to make the spin tune spread very small. In recent experiment, 97% spin-flip efficiency was measured at both 24 and 255 GeV for the first time. The results show that efficient spin flipping can be achieved at high energies.

Poster MOPAB014 [0.984 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB014

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paper received ※ 16 May 2021 paper accepted ※ 08 June 2021 issue date ※ 20 August 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

alignment, beam-losses, emittance, operation

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

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

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MOPAB024

Efficient Coupling of Hydrodynamic and Energy-Deposition Codes for Hydrodynamic-Tunnelling Studies on High-Energy Particle Accelerators

simulation, target, coupling, proton

119

C. Wiesner, F. Carra, J. Kruse-Hansen, M. Masci, D. Wollmann
CERN, Meyrin, Switzerland
Y. Nie
KIT, Karlsruhe, Germany

The machine-protection evaluation of high-energy accelerators comprises the study of beyond-design failures, including the direct beam impact onto machine elements. In case of a direct impact, the nominal beam of the Large Hadron Collider (LHC) would penetrate more than 30 meters into a solid copper target. The penetration depth due to the time structure of the particle beam is, thus, significantly longer than predicted from purely static energy-deposition simulations with 7 TeV protons. This effect, known as hydrodynamic tunnelling, is caused by the beam-induced density depletion of the material at the target axis, which allows subsequent bunches to penetrate deeper into the target. Its proper simulation requires, therefore, to sequentially couple an energy-deposition code and a hydrodynamic code for the different target densities. This paper describes a method to efficiently couple the simulations codes Autodyn and FLUKA based on automatic density assignment and input file generation, and presents the results achieved for a sample case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB024

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paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 28 August 2021

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MOPAB026

RHIC Delayed Abort Experiments

kicker, injection, quadrupole, dipole

126

M. Valette, D. Bruno, K.A. Drees, K.M. Hartmann, G. Heppner, K. Mernick, C. Mi, J.-L. Mi, R.J. Michnoff, J. Morris, F. Orsatti, E. Rydout, T. Samms, J. Sandberg, V. Schoefer, C. Schultheiss, T.C. Shrey, C. Theisen
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.
For RHIC to operate at its top energy (100 GeV/n) while protecting the future sPHENIX detector, spontaneous and asynchronous firing of abort kicker modules (pre-fires) have to be avoided. A new triggering circuit for the abort kickers was implemented with relatively slow mechanical relays in series with the standard fast thyratron tubes. The relays prevents unwanted pre-fires during operation, but comes at the expense of a long latency - about 7 milliseconds - between the removal of beam permit and the actual firing of the abort kickers. Protection considerations of RHIC’s superconducting magnets forbid delaying energy extraction from the main dipoles and quadrupoles for too long after a quench. The beam has thus to circulate in both RHIc rings for a few milliseconds as the current in dipole and quadrupole circuit is being extracted. We present the results of delayed abort experiments conducted in July 2018 with the analysis of fast orbit and tune measurements and discuss the safety implications of this implementation for future RHIC operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB026

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paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 23 August 2021

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MOPAB029

Burn-Off with Asymmetric Interaction Points

luminosity, emittance, simulation, controls

138

R. Tomás García, I. Efthymiopoulos, G. Iadarola
CERN, Geneva, Switzerland

LHC can host above 2700 proton bunches per ring providing collisions in the ATLAS, CMS, LHCb and ALICE interaction points. ATLAS and CMS are placed symmetrically so that they feature the same colliding bunch pairs. However this is not the case for LHCb, hence introducing unwanted bunch-by-bunch variations of the bunch intensity as the physics fill evolves. We present first analytical derivations, numerical simulations and experimental data in different bunch train collision configurations.

Poster MOPAB029 [1.502 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB029

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paper received ※ 13 May 2021 paper accepted ※ 25 May 2021 issue date ※ 27 August 2021

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MOPAB034

VEPP-4M Collider Operation at High Energy

collider, luminosity, electron, positron

155

P.A. Piminov, G.N. Baranov, A.V. Bogomyagkov, V.M. Borin, V.L. Dorokhov, S.E. Karnaev, K.Yu. Karyukina, V.A. Kiselev, E.B. Levichev, O.I. Meshkov, S.I. Mishnev, I.A. Morozov, I.N. Okunev, E.A. Simonov, S.V. Sinyatkin, E.V. Starostina, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia

VEPP-4M is an electron positron collider equipped with the universal KEDR detector for HEP experiments in the beam energy range from 1 GeV to 6 GeV. A unique feature of VEPP-4M is the high precision beam energy calibration by resonant polarization technique which allows conducting of interesting experiments despite the low luminosity of the collider. Recently we have started new luminosity acquisition run above 2 GeV. The hadron cross section was measured from 2.3 GeV to 3.5 GeV has been done. The luminosity run for gamma-gamma physics has been started. The luminosity at ψ(1S)-meson has been obtained. For the beam energy calibration the laser polarimeter is used. The paper discusses recent results from VEPP-4M collider.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB034

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

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MOPAB077

Anomaly Detection in Accelerator Facilities Using Machine Learning

power-supply, operation, GUI, 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]

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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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MOPAB084

Acceptance Tests and Installation of the IVU and Front End for the XAIRA Beamline of ALBA

undulator, photon, vacuum, insertion

318

J. Campmany, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

XAIRA is a new beamline being built at ALBA synchrotron for macromolecular crystallography (MX) devoted to the study of small bio crystals. It aims at providing a full beam with a size of 3x1 µm² FWHM (hxv) and flux of >3·10¹² ph/s (250 mA in Storage Ring) at 1 Å wavelength (12.4 keV) to tackle MX projects for which only tiny (<10 μm) or imperfect crystals are obtained. Besides, XAIRA aims at providing photons at low energies, down to 4 keV, to support MX experiments exploiting the anomalous signal of the metals naturally occurring in proteins (native phasing), which is enhanced in the case of small crystals and long wavelengths. To this end, an in-vacuum undulator has been built by a consortium between Kyma and Research Instruments companies. In this paper, we present the results of the Site Acceptance Tests made at ALBA using a new bench developed to measure closed structures, and also the steps done for its installation in the ALBA tunnel.

Poster MOPAB084 [1.715 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB084

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paper received ※ 11 May 2021 paper accepted ※ 20 May 2021 issue date ※ 25 August 2021

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MOPAB096

Rocking Curve Imaging Experiment at SSRL 10-2 Beamline

photon, wiggler, radiation, lattice

357

A. Halavanau, R. Arthur, B. Johnson, J.P. MacArthur, G. Marcus, R.A. Margraf, Z. Qu, T. Rabedeau, T. Sato, C.J. Takacs, D. Zhu
SLAC, Menlo Park, California, USA

Stanford Synchrotron Radiation Lightsource (SSRL) serves a wide scientific community with its variety of X-ray capabilities. Recently, we have employed a wiggler source located at beamline 10-2 to perform high resolution rocking curve imaging (RCI) of diamond and silicon crystals. In-house X-ray RCI capability is important for the upcoming cavity-based x-ray source development projects at SLAC, such as cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO). In this proceeding, we describe theoretical considerations, and provide experimental results, validating the design of our apparatus. We also provide a plan for future improvements of the RCI@SSRL program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB096

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

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MOPAB098

LCLS Multi-Bunch Improvement Plan

laser, FEL, linac, electron

365

A. Halavanau, S. Carbajo, F.-J. Decker, A.K. Krasnykh, A.A. Lutman, A. Marinelli, C.E. Mayes, D.C. Nguyen
SLAC, Menlo Park, California, USA

Current and future experiments at LCLS require XFEL pulse trains of variable time separation. The cavity based XFEL (CBXFEL) project requires multiple pulses separated by 220 ns, the X-ray Laser Oscillator (XLO) uses 15 ns spaced pulse trains and Matter under Extreme Conditions (MEC) experiments need a shortly spaced (less than 5 ns) pulse trains. In this proceeding, we discuss the LCLS multi-bunch improvement plan and report on its recently status and progress.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB098

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 20 August 2021

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MOPAB100

Progress Report on Population Inversion-Based X-Ray Laser Oscillator

FEL, laser, electron, radiation

373

A. Halavanau, R. Alonso-Mori, A. Aquila, U. Bergmann, D. DePonte, F.-J. Decker, F. Fuller, M. Liang, A.A. Lutman, C. Pellegrini
SLAC, Menlo Park, California, USA
M. Doyle
UCB, Berkeley, USA

The population inversion X-ray Laser Oscillator (XLO) is a fully coherent, transform limited hard X-ray source. It operates by repetitively pumping inner-shell atomic transitions with an XFEL, in a closed Bragg cavity. XLO will produce very bright monochromatic X-ray pulses for applications in quantum optics, X-ray interferometry and metrology. We report the progress to build the first XLO operating at the copper alpha line, using LCLS 9 keV SASE X-ray pulses as a pump.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB100

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paper received ※ 20 May 2021 paper accepted ※ 29 July 2021 issue date ※ 02 September 2021

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MOPAB101

Hollow and Flat Electron Beam Generation at FACET-II

electron, emittance, wakefield, quadrupole

376

A. Halavanau, S.J. Gessner, C.E. Mayes
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA

In this proceeding, we investigate hollow and flat electron beam generation at FACET-II facility. We focus on the case of a circular beamlet arrangement, also known as ’necklace’ beams. We study, via numerical simulations, the resulting e-beam dynamics in the FACET-II photoinjector, beam propagation through the high energy section, as well as possible experimental applications of the ’necklace’ beams. Finally, we evaluate the feasibility of high charge flat beam generation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB101

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

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MOPAB132

The Multi-Mega-Watt Target Station for the European Spallation Source Neutrino Super Beam

target, proton, hadron, ion-source

466

E. Baussan, E. Bouquerel, L. D’Alessi, M. Dracos, P. Poussot, J. Thomas, J. Wurtz, V. Zeter
IPHC, Strasbourg Cedex 2, France
P. Cupial, M. Koziol, L.J. Lacny, J. Snamina
AGH University of Science and Technology, Kraków, Poland
I. Efthymiopoulos
CERN, Meyrin, Switzerland
T. Tolba
University of Hamburg, Hamburg, Germany

Funding: This project has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 777419 and also by the Deutsche Forschungsgemeinschaft No 423761110.
One of the next challenges in fundamental physics is to understand the origin of matter/antimatter asymmetry in the Universe. In particular, intense neutrinos could play an important role to elucidate this mystery and better understand the expansion of the Universe. The ESSnuSB collaboration proposes to use the proton linac of the European Spallation Source currently under construction in Lund (Sweden) to produce a very intense neutrino super beam, in parallel with the spallation neutron production. A very challenging part of the proposed facility is the Target Station which will have to afford 5 MW proton beam power. This poster will present the hadronic collector and the whole facility to produce the next generation of neutrino superbeam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB132

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paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 18 August 2021

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MOPAB134

Normalized Transverse Emittance Reduction via Ionization Cooling in MICE ’Flip Mode’

emittance, simulation, solenoid, betatron

474

P.B. Jurj
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Low emittance muon beams are central to the development of a Muon Collider and can significantly enhance the performance of a Neutrino Factory. The international Muon Ionization Cooling Experiment (MICE) has recorded several million individual muon tracks passing through a liquid hydrogen or a lithium hydride absorber and has demonstrated the ionization cooling of muon beams. Previous analysis used a restricted data set, and the beam matching was not perfect. In this analysis, beam sampling routines were employed to account for imperfections in beam matching at the entrance into the cooling channel and enable an improvement of the cooling measurement. A study of the normalized transverse emittance change in the MICE cooling channel set up in a flipped polarity magnetic field configuration is presented. Additionally, the evolution of the canonical angular momentum across the absorber is shown and the characteristics of the cooling effect are discussed.

Poster MOPAB134 [1.821 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB134

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

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MOPAB137

Interaction Region Design for DWA Experiments at FACET-II

electron, radiation, alignment, diagnostics

478

O. Williams, G. Andonian, A. Fukasawa, W.J. Lynn, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, Y. Sakai, M. Yadav, Y. Zhuang
UCLA, Los Angeles, California, USA
C.I. Clarke, M.J. Hogan, B.D. O’Shea, D.W. Storey, V. Yakimenko
SLAC, Menlo Park, California, USA
M. Ruelas
RadiaBeam, Santa Monica, California, USA
M. Yadav
The University of Liverpool, Liverpool, United Kingdom

Funding: DOE HEP Grant DE-SC0009914
The extremely intense beam generated at FACET-II provides the unique opportunity to investigate the effects of beam-driven GV/m fields in dielectrics exceeding meter-long interaction lengths. The diverse range of phenomena to be explored, such as material response in the terahertz regime, suppression of high-field pulse damping effects, advanced geometry structures, and methods for beam break up (BBU) mitigation, all within a single UHV vacuum vessel, requires flexibility and precision in the experimental layout. We present here details of the experimental design for the dielectric program at FACET-II. Specifically, consideration is given to the alignment of the dielectric structures due to the extreme fields associated with the electron beam, as well as implementation of electron beam and Cherenkov radiation-based diagnostics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB137

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

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MOPAB138

Dielectric Wakefield Acceleration with a Laser Injected Witness Beam

wakefield, laser, cathode, simulation

481

G. Andonian, T.J. Campese
RadiaBeam, Santa Monica, California, USA
N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
W.J. Lynn, N. Majernik, J.B. Rosenzweig, V.S. Yu
UCLA, Los Angeles, California, USA

Funding: Work supported by DOE grant DE-SC0017690
The plasma photocathode concept, whereby a two-species gas mixture is used to generate a beam -driven accelerating wakefield and a laser-ionized generation of a witness beam, was recently experimentally demonstrated. In a variation of this concept, a beam-driven dielectric wakefield accelerator is employed, filled with a neutral gas for laser-ionization and creation of a witness beam. The dielectric wakefields, in the terahertz regime, provide comparatively modest timing requirements for the injection phase of the witness beam. In this paper, we provide an update on the progress of the experimental realization of the hybrid dielectric wakefield accelerator with laser injected witness beam at the Argonne Wakefield Accelerator (AWA), including engineering considerations for gas delivery, and preliminary simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB138

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021

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MOPAB139

High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM

electron, focusing, quadrupole, target

485

G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas
RadiaBeam, Marina del Rey, California, USA
M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu
BNL, Upton, New York, USA
C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA

Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139

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paper received ※ 26 May 2021 paper accepted ※ 28 May 2021 issue date ※ 18 August 2021

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MOPAB148

Liénard-Wiechert Numerical Radiation Modeling for Plasma Acceleration Experiments at FACET-II

radiation, plasma, betatron, acceleration

517

M. Yadav, G. Andonian, C.E. Hansel, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams, Y. Zhuang
UCLA, Los Angeles, California, USA
G. Andonian
RadiaBeam, Marina del Rey, California, USA
O. Apsimon, A. Perera, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
O. Apsimon, A. Perera, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by DE-SC0009914 (UCLA) and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1.
Future plasma acceleration experiments at FACET-II will measure betatron radiation in order to provide single-shot non-destructive beam diagnostics. We discuss three models for betatron radiation: a new idealized particle tracking code with Liénard-Wiechert radiation, a Quasi-Static Particle-in-Cell (PIC) code with Liénard-Wiechert radiation, and a full PIC code with radiation computed via a Monte-Carlo QED Method. Predictions of the three models for the E-310 experiment are presented and compared. Finally, we discuss beam parameter reconstruction from the double differential radiation spectrum.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB148

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paper received ※ 24 May 2021 paper accepted ※ 01 June 2021 issue date ※ 17 August 2021

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MOPAB152

High Power Tests of Brazeless Accelerating Structures

GUI, simulation, wakefield, target

532

S.P. Antipov, P.V. Avrakhov, C.-J. Jing, S.V. Kuzikov
Euclid TechLabs, Solon, Ohio, USA
V.A. Dolgashev
SLAC, Menlo Park, California, USA
D.S. Doran, W. Liu, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: DOE SBIR Grant #DE-SC0017749
A typical accelerating structure is a set of copper resonators brazed together. This multi step process is expensive and time consuming. In an effort to optimize production process for rapid prototyping and overall reduction of accelerator cost we developed a split block brazeless accelerating structure. In such structure the vacuum is sealed by the use of knife edges, similar to an industry standard conflat technology. In this paper we present high power tests of several different brazeless structures. First, an inexpensive 1 MeV accelerator powered by radar magnetron. Second, a high gradient power extractor tested at Argonne Wakefield Accelerator Facility. In this experiment a high charge electron beam generated a 180 MW peak power pulse. Finally, we report on high power testing of a brazeless x-band accelerating structure at SLAC.

Poster MOPAB152 [0.783 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB152

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 31 August 2021

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MOPAB162

The First Trial of XY-Coupled Beam Phase Space Matching for Three-Dimensional Spiral Injection

injection, coupling, site, solenoid

553

M.A. Rehman, K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa, N. Saito, K. Sasaki
KEK, Ibaraki, Japan
H. Hirayama, H. Iinuma, K. Oda
Ibaraki University, Ibaraki, Japan
R. Matsushita
The University of Tokyo, Graduate School of Science, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: Work supported by "Grant in Aid" for Scientific Research, JSPS (KAKENHI# 26287055, KAKENHI#19H00673)
The most recent measurement of muon g-2 results in a 3.8σ discrepancy with the equally precise theoretical prediction. The J-PARC muon g-2/EDM experiment (E34) is in preparation to decipher this discrepancy and unravel the new physics beyond the standard model. The precision goal for g-2 is 0.1 ppm. To achieve this precision goal a novel 3-D spiral injection scheme has been devised to inject and store the beam into a small diameter MRI-type storage magnet for E34. The new injection scheme features smooth injection with high storage efficiency for the compact magnet. However, the spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) at KEK Tsukuba Campus is underway to establish this injection scheme. Due to the axial symmetric field of the solenoid magnet, a strongly XY-coupled beam is required. To produce the required phase space for the solenoid-type storage magnet, a beam transport line consisting of three rotatable quadrupole magnets has been designed and built for SITE. The vertical beam size reduction by means of phase space matching and other geometrical information has been successfully measured by the wire scanners.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB162

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paper received ※ 20 May 2021 paper accepted ※ 28 May 2021 issue date ※ 01 September 2021

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MOPAB168

Nanoplasmonic Accelerators Towards Tens of TeraVolts per Meter Gradients Using Nanomaterials

electron, plasma, wakefield, focusing

574

A.A. Sahai, M. Golkowski, V. Harid
CU Denver, Denver, Colorado, USA
C. Joshi
UCLA, Los Angeles, California, USA
T.C. Katsouleas
Duke ECE, Durham, North Carolina, USA
A. Latina, F. Zimmermann
CERN, Geneva, Switzerland
J. Resta-López
Cockcroft Institute, Warrington, Cheshire, United Kingdom
P. Taborek
UCI, Irvine, California, USA
A.G.R. Thomas
University of Michigan, Ann Arbor, Michigan, USA

Funding: University of Colorado Denver
Ultra-high gradients which are critical for future advances in high-energy physics, have so far relied on plasma and dielectric accelerating structures. While bulk crystals were predicted to offer unparalleled TV/m gradients that are at least two orders of magnitude higher than gaseous plasmas, crystal-based acceleration has not been realized in practice. We have developed the concept of nanoplasmonic crunch-in surface modes which utilizes the tunability of collective oscillations in nanomaterials to open up unprecedented tens of TV/m gradients. Particle beams interacting with nanomaterials that have vacuum-like core regions, experience minimal disruptive effects such as filamentation and collisions, while the beam-driven crunch-in modes sustain tens of TV/m gradients. Moreover, as the effective apertures for transverse and longitudinal crunch-in wakes are different, the limitation of traditional scaling of structure wakefields to smaller dimensions is significantly relaxed. The SLAC FACET-II experiment of the nano2WA collaboration will utilize ultra-short, high-current electron beams to excite nonlinear plasmonic modes and demonstrate this possibility.
* doi:10.1109/ACCESS.2021.3070798
** doi:10.1142/S0217751X19430097
*** indico.fnal.gov/event/19478/contributions/52561
**** indico.cern.ch/event/867535/contributions/3716404

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB168

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paper received ※ 11 May 2021 paper accepted ※ 08 June 2021 issue date ※ 20 August 2021

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MOPAB169

Generating 510 MW of X-Band Power for Structure-Based Wakefield Acceleration Using a Metamaterial-Based Power Extractor

wakefield, acceleration, electron, simulation

578

J.F. Picard, I. Mastovsky, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
M.E. Conde, D.S. Doran, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid TechLabs, Solon, Ohio, USA
X. Lu
Northern Illinois University, DeKalb, Illinois, USA

Funding: Research sponsored under Award No. DE-SC0015566 by U.S. Department of Energy, Office of Science, Office of High Energy Physics and Contract No. DE-AC02-06CH11357 by the Office of Science.
We present our recent results generating 510 MW of power at 11.7 GHz using a metamaterial-based metallic power-extractor for application in structure-based wakefield acceleration (SWFA). SWFA is a novel acceleration scheme in which high-charge electron bunches are passed through a power extractor structure to produce a high-intensity wakefield. This wakefield can then be used to accelerate a witness bunch in the same beamline or passed to a separate acceleration beamline. MIT’s approach uses a specialized metamaterial for the power extractor design. By using a metamaterial, we can overcome some of the challenges faced by other SWFA techniques. Here, we discuss the Stage 3 experiment. The Stage 1 and Stage 2 experiments successfully demonstrated the functionality of the metamaterial approach by generating high power RF pulses using the 65 MeV electron beam at the Argonne Wakefield Accelerator (AWA) facility. The 510 MW result from Stage 3 experiment is the highest power generated to-date for SWFA at AWA, and was enable by significant design improvements, including an all-copper structure, fully-symmetric coupler design, and breakdown risk-reduction treatment.

Poster MOPAB169 [8.882 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB169

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paper received ※ 08 May 2021 paper accepted ※ 16 July 2021 issue date ※ 25 August 2021

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MOPAB173

Physics Program and Experimental for AWAKE Run 2

plasma, electron, wakefield, proton

586

P. Muggli
MPI, Muenchen, Germany

Run 1 experimental results demonstrate many characteristics of the self-modulation (SM) in plasma of a long, 400GeV SPS proton bunch*. Externally injected, 19MeV electrons were accelerated to 2GeV**. Based on these results, we are assembling a physics and experiment program aiming at producing a multi-GeV electron bunch with emittance and energy spread sufficiently low for possible early applications to high-energy physics experiments. Plans include two plasmas, the first for SM, the second for acceleration, and of scalable length, separated by an injection region. The first plasma includes a density step to maintain large-amplitude wakefields after saturation of the SM process. Seeding of the SM process may be obtained from an electron bunch. The 150MeV witness electron bunch from an S-band gun, X-band linac has parameters that produce plasma electron blow out and loading of the wakefields in order to minimize final energy spread and emittance***. We are studying the possibility of using a helicon plasma source for the accelerator, a source that can in principle be very long (100s of m).
*AWAKE, PRL 122, 054802 (2019), Turner, PRL 122, 054801 (2019), Turner, PRAB 23, 081302, (2020), Braunmueller PRL 125, 264801 (2020)
**AWAKE, Nature 561, 363 (2018)
***Olsen, PRAB 21, 011301 (2018)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB173

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paper received ※ 18 May 2021 paper accepted ※ 28 May 2021 issue date ※ 02 September 2021

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MOPAB177

ELENA Commissioning and Status

proton, antiproton, MMI, electron

598

C. Carli, M.E. Angoletta, W. Bartmann, L. Bojtár, F. Butin, B. Dupuy, Y. Dutheil, M.A. Fraser, P. Freyermuth, D. Gamba, L.V. Jørgensen, B. Lefort, O. Marqversen, M. McLean, S. Ogur, S. Pasinelli, L. Ponce, G. Tranquille
CERN, Geneva, Switzerland

The Extra Low ENergy Antiproton ring ELENA is a small synchrotron recently constructed and commissioned to decelerate antiprotons injected from the Antiproton Decelerator AD with a kinetic energy of 5.3 MeV down to 100 keV. Controlled deceleration in the synchrotron, equipped with an electron cooler to reduce losses and generate dense bunches, allows the experiments, typically capturing the antiprotons in traps and manipulating them further, to improve the trapping efficiency by one to two orders of magnitude. During 2018, bunches with an energy of 100 keV with parameters close to nominal have been demonstrated, and first beams have been provided to an experiment in a new experimental zone. The magnetic transfer lines from the AD to the experiments have been replaced by electrostatic lines from ELENA. Commissioning of the new transfer lines and, in parallel, studies to better understand the ring with H⁻ beams from a dedicated source, have started in autumn 2020. The first 100 keV antiproton physics run using ELENA will start in late summer 2021.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB177

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

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MOPAB179

Simulations of AGS Boosters Imperfection Resonances for Protons and Helions

resonance, proton, simulation, quadrupole

606

K. Hock, H. Huang, F. Méot, N. Tsoupas
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
As part of the effort to increase the polarization of the proton beam for the physics experiments at RHIC, a scan of orbit harmonic corrector strengths is performed in the Booster to ensure polarization transmission through the |G gamma|=3 and 4 imperfection resonances is optimized. These harmonic scans have been simulated using quadrupole alignment data and accurately match experimental data. The method used to simulate polarized protons is extended to polarized helions for crossing the |G gamma|=5 through |G gamma|=10 imperfection resonances and used to determine the corrector strength required to cross each resonance.

Poster MOPAB179 [0.437 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB179

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 02 September 2021

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MOPAB189

Beam Commissioning of XiPAF Synchrotron

extraction, synchrotron, injection, MMI

639

H.J. Yao, X. Guan, Y. Li, X.Y. Liu, M.W. Wang, X.W. Wang, Y. Yang, W.B. Ye, H.J. Zeng, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, Z.M. Wang
NINT, Shannxi, People’s Republic of China

XiPAF (Xi’an 200MeV Proton Application Facility) is a project to fulfill the need for the experimental simulation of the space radiation environment. It comprises a 7 MeV H⁻ linac, a 60-230 MeV proton synchrotron, and experimental stations. The Installation of the synchrotron, beamline and one experimental station were completed at the end of December 2019, and commissioning has just begun. Circulating beam around the synchrotron was observed on the first day of operation, and now 10-200 MeV proton beam directly extracted from the synchrotron had been transported to the experimental station for user experiments. The results of the commissioning and data analysis are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB189

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paper received ※ 18 May 2021 paper accepted ※ 21 May 2021 issue date ※ 17 August 2021

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MOPAB194

First 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac rf Cavities

cavity, vacuum, cyclotron, linac

654

H. Hähnel, U. Ratzinger
IAP, Frankfurt am Main, Germany

Additive manufacturing (or "3D printing") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. As technology is evolving, the quality and accuracy of parts manufactured this way is ever improving. Especially interesting for the world of particle accelerators is the process of 3D printing of stainless steel (and copper) parts. We present the first fully functional IH-type drift tube structure manufactured by metal 3D printing. A 433 MHz prototype cavity has been constructed to act as a proof-of-concept for the technology. The cavity is designed to be UHV capable and includes cooling channels reaching into the stems of the DTL structure. We present the first experimental results for this prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB194

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paper received ※ 18 May 2021 paper accepted ※ 01 June 2021 issue date ※ 02 September 2021

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MOPAB195

Development of a Disk-and-Washer Cavity for the J-PARC Muon g-2/EDM Experiment

cavity, linac, quadrupole, coupling

658

Y. Takeuchi, J. Tojo
Kyushu University, Fukuoka, Japan
E. Cicek, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R. Kitamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue, K. Sumi, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

At J-PARC, an experiment using muons accelerated by a linac is planned to measure the anomalous magnetic moment of muons and to search for the electric dipole moment. A 1296 MHz disk and washer (DAW) coupled cavity linac (CCL) is being developed for use in the middle beta section of the muon linac. The DAW CCL consists of 14 tanks with 11 cells each. All tanks are connected by bridge couplers and electromagnetic quadrupole doublets for focusing are installed in each bridge coupler. The basic design of the DAW cavity has already been completed, and now detailed cavity design studies and manufacturing process studies are underway. In this poster, we will report about these studies and the preparation status of manufacturing the DAW cavity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB195

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paper received ※ 20 May 2021 paper accepted ※ 01 June 2021 issue date ※ 23 August 2021

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MOPAB217

A Storage Ring for MESA

target, optics, simulation, operation

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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MOPAB221

Developments of a Pulse Kicker System for the Three-Dimensional Spiral Beam Injection of the J-PARC Muon g-2/EDM Experiment

kicker, injection, power-supply, solenoid

726

K. Oda, H. Hirayama, H. Iinuma, Y. Sato, M. Sugita
Ibaraki University, Ibaraki, Japan
M. Abe, K. Furukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki
KEK, Ibaraki, Japan
R. Matsushita
The University of Tokyo, Graduate School of Science, Tokyo, Japan

The J-PARC muon g-2/EDM experiment aims to perform ultra-precise measurements of anomalous magnetic moments (g-2) and electric dipole moments (EDM) from the spin precession of muons in a precise magnetic field and to explore new physics beyond the Standard Model. On experimental requirements, the beam must be stored in a compact storage orbit with a diameter of 66 cm, which is about 1/20th smaller than that of the previous experiment. To be realized, we adopt an unprecedented injection technique called the three-dimensional spiral injection scheme. In this scheme, the beam is injected from upward of the solenoidal storage magnet. The vertical beam motion along the solenoid axis is controlled by a few 100 ns pulse kicker. Once the beam is guided into the center fiducial storage volume, the muon beam is stored by the weak focusing magnetic field. Therefore, stable and accurate control of the pulse kicker is one of the major technical challenges to realize the ultra-precise measurement of the muon spin precession. In this presentation, we discuss the performance of the prototype pulse kicker device and future plan for installation of it to our test bench with an electron beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB221

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paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 15 August 2021

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MOPAB241

Design of the Proton and Electron Transfer Lines for AWAKE Run 2c

plasma, electron, proton, acceleration

778

R.L. Ramjiawan
JAI, Oxford, United Kingdom
S. Döbert, E. Gschwendtner, P. Muggli, F.M. Velotti, L. Verra
CERN, Meyrin, Switzerland
J.P. Farmer
MPI-P, München, Germany
P. Muggli
MPI, Muenchen, Germany

The AWAKE Run 1 experiment achieved electron acceleration to 2 GeV using plasma wakefield acceleration driven by 400 GeV, self-modulated proton bunches from the CERN SPS. The Run 2c phase of the experiment aims to build on these results by demonstrating acceleration to ~10 GeV while preserving the quality of the accelerated electron beam. To realize this, there will be an additional plasma cell, to separate the proton bunch self-modulation and the electron acceleration. A new 150 MeV beamline is required to transport and focus the witness electron beam to a beam size of several microns at the injection point. This specification is designed to preserve the beam emittance during acceleration, also requiring micron-level stability between the driver and witness beams. To facilitate these changes, the Run 1 proton transfer line will be reconfigured to shift the first plasma cell 40 m downstream. The Run 1 electron beamline will be adapted and used to inject electron bunches into the first plasma cell to seed the proton bunch self-modulation. Proposed adjustments to the proton transfer line and studies for the designs of the two electron transfer lines are detailed in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB241

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 17 August 2021

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MOPAB256

Development of Pulsed Beam System for the Three Dimensional Spiral Injection Scheme in the J-PARC muon g-2/EDM Experiment

injection, kicker, power-supply, controls

809

R. Matsushita
The University of Tokyo, Graduate School of Science, Tokyo, Japan
M. Abe, K. Hurukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki
KEK, Ibaraki, Japan
H. Hirayama, H. Iinuma, K. Oda, Y. Sato, M. Sugita
Ibaraki University, Ibaraki, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Takayanagi
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC muon g-2/EDM experiment aims to measure the anomalous magnetic moment(g-2) and electric dipole moment(EDM) of the muon with higher precision than the previous BNL E821 experiment. A brand-new three-dimensional spiral injection scheme is employed to inject and store muon beam into a 66 cm diameter of storage magnet. Feasibility studies are ongoing by use of 80 keV electron beam at KEK test bench, to develop skills on control transverse beam motion; so-called X-Y coupling, with DC beam. As a next step, towards store the beam by use of a kicker system, a pulsed beam should be generated from the DC beam with an intended time structure to meet a pulse kicker’s duration time, without changing transverse phase space characteristics. In this presentation, the development of a beam chopper device and the evaluation of pulse beam profile are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB256

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paper received ※ 20 May 2021 paper accepted ※ 15 June 2021 issue date ※ 16 August 2021

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MOPAB267

End to End Simulations of Antiproton Transport and Degradation

simulation, proton, antiproton, electron

847

S. Padden, E. Kukstas, P. Pusa, V. Rodin, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
K. Nordlund
HIP, University of Helsinki, Finland
V. Rodin, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The ELENA ring decelerates anti-protons to 100 keV down from 5.3 MeV with transport to experiments handled by electrostatic transfer lines. Even at 100 keV antiprotons are still too high in energy for direct injection into an ion trap, and this is why degrader foils are used to further lower the energy. This contribution presents full end-to-end simulations from the point of extraction until passing through the foil using realistic beam transport simulations coupled with accurate simulations of degrader foils via the use of density functional theory and molecular dynamics. Particles are tracked from the point of extraction until their injection into the trap with full physical modeling at all time steps. The results of this study provide a versatile platform for the optimization of low energy ion experiments towards specific targets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB267

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 24 August 2021

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MOPAB273

Nonlinear Coupling Resonances in X-Y Coupled Betatron Oscillations Near the Main Coupling Resonance in VEPP-2000 Collider

resonance, betatron, coupling, collider

863

S.A. Kladov, E. Perevedentsev
BINP SB RAS, Novosibirsk, Russia
S.A. Kladov, E. Perevedentsev
NSU, Novosibirsk, Russia

In the vicinity of the linear coupling resonance where the working point of the collider is positioned, we study the effect of nonlinear coupling resonances on the single-particle phase space, beam sizes and the waveform of coherent beam motion. The latter is interesting for diagnostics of the nonlinear dynamics.

Poster MOPAB273 [1.142 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB273

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

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MOPAB280

Split Ring Resonator Experiment - Simulation Results

simulation, laser, electron, solenoid

888

J. Schäfer, B. Härer, A. Malygin, A.-S. Müller, M. Nabinger, M.J. Nasse, T. Schmelzer, M. Schuh, T. Windbichler
KIT, Karlsruhe, Germany

Funding: Supported by "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)" and European Union’s Horizon 2020 Research and Innovation programme.
FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D. An example for a new accelerator diagnostics tool currently studied at FLUTE is the split-ring-resonator (SRR) experiment, which aims to measure the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Particles passing through the SRR gap are time-dependently deflected in the vertical plane, which allows a vertical streaking of an electron bunch. This principle allows a diagnosis of the longitudinal bunch profile in the femtosecond time domain and will be tested at FLUTE. This contribution presents an overview of the SRR experiment and the results of various tracking simulations for different scenarios as a function of laser pulse length and bunch charge. Based on these results possible working points for the experiments at FLUTE will be proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB280

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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MOPAB281

Research on Resolution Evaluation of Stripline BPM at SXFEL-UF

FEL, network, electron, linac

892

B. Gao, J. Chen, Y.B. Leng
SSRF, Shanghai, People’s Republic of China

48 stripline BPMs are installed in the injection section and linear acceleration section of Shanghai X-ray Free Electron Laser (SXFEL) for electron beam position measurement. These two sections require resolution of 20 µm@100pC. Resolution evaluation is an important step in BPM installation and commissioning. This paper presents BPM resolution evaluation methods based on correlation analysis. Experimental methods, data processing and result analysis will be discussed

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB281

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

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MOPAB282

Development of a Multi-Camera System for Non-Invasive Intense Ion Beam Investigations

diagnostics, ion-source, solenoid, vacuum

895

A. Ateş, H. Hähnel, U. Ratzinger, K. Volk, C. Wagner
IAP, Frankfurt am Main, Germany

The continued popularity of miniaturized cameras integrated into smartphones is leading to further research for more advanced CMOS camera sensors. This made CMOS technology even superior to scientific CCD cameras. Due to the lower power consumption and high flexibility, a multicamera system can be developed more effectively. At the Institute of Applied Physics at Goethe University Frankfurt (IAP) a prototype of a beam induced rest gas fluorescence monitor (BIF) was developed and tested successfully. The BIF consists of x and y single board cameras integrated into the vacuum chamber. A multi-camera system was installed in the LEBT area of the FRANZ project at the IAP within the first diagnostic chamber. This system consists of six cameras. With this equipment it is possible to investigate the beam along a 484 mm path in x and y direction. The developments on the reconstruction and image processing methods are in progress.

Poster MOPAB282 [1.139 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB282

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paper received ※ 12 May 2021 paper accepted ※ 08 June 2021 issue date ※ 24 August 2021

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MOPAB286

Towards a Data Science Enabled MeV Ultrafast Electron Diffraction System

electron, network, real-time, laser

906

M.A. Fazio, S. Biedron, M. Martínez-Ramón, D.J. Monk, S.I. Sosa Guitron
UNM-ECE, Albuquerque, USA
M. Babzien, K.A. Brown, M.G. Fedurin, J.J. Li, M.A. Palmer, J. Tao
BNL, Upton, New York, USA
S. Biedron, T. Talbott
UNM-ME, Albuquerque, New Mexico, USA
J. Chen, A.J. Hurd, N.A. Moody, R. Prasankumar, C. Sweeney
LANL, Los Alamos, New Mexico, USA
D. Martin, M.E. Papka
ANL, Lemont, Illinois, USA

Funding: US DOE, SC, BES, MSE, award DE-SC0021365 and DOE NNSA award 89233218CNA000001 through DOE’s EPSCoR program in Office of BES with resources of DOE SC User Facilities BNL’s ATF and ALCF.
A MeV ultrafast electron diffraction (MUED) instrument is a unique characterization technique to study ultrafast processes in materials by a pump-probe technique. This relatively young technology can be advanced further into a turn-key instrument by using data science and artificial intelligence (AI) mechanisms in conjunctions with high-performance computing. This can facilitate automated operation, data acquisition and real time or near- real time processing. AI based system controls can provide real time feedback on the electron beam which is currently not possible due to the use of destructive diagnostics. Deep learning can be applied to the MUED diffraction patterns to recover valuable information on subtle lattice variations that can lead to a greater understanding of a wide range of material systems. A data science enabled MUED facility will also facilitate the application of this technique, expand its user base, and provide a fully automated state-of-the-art instrument. We will discuss the progress made on the MUED instrument in the Accelerator Test Facility of Brookhaven National Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB286

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paper received ※ 20 May 2021 paper accepted ※ 09 June 2021 issue date ※ 25 August 2021

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MOPAB287

The Development of Single Pulse High Dynamic Range BPM Signal Detector Design at AWA

detector, electron, pick-up, electronics

909

E.M. Siebert, S. Baturin
Northern Illinois University, DeKalb, Illinois, USA
D.S. Doran, G. Ha, W. Liu, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: the US Department of Energy, Office of Science
Single pulse high dynamic range BPM signal detector has been on the most wanted list of Argonne Wakefield Accelerator (AWA) Test Facility for many years. Unique capabilities of AWA beamline require BPM instrumentation with an unprecedented dynamic range, thus cost effective solution could be challenging to design and prototype. Our most recent design, and the results of our quest for a solution, are shared in this paper.

Poster MOPAB287 [1.372 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB287

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

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MOPAB293

Electro-Optical Diagnostics at KARA and FLUTE - Results and Prospects

diagnostics, electron, laser, storage-ring

927

G. Niehues, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, M.M. Patil, R. Ruprecht, M. Schuh, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: S.F. was funded by BMBF contract No. 05K16VKA, C. W. by BMBF contract number 05K19VKD. G.N. and E.B. acknowledge support by the Helmholtz President’s strategic fund IVF "Plasma Accelerators".
Electro-optical (EO) methods are nowadays well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). These measurements facilitate studies of physical conditions to provide, at the end, intense and stable CSR in the THz range. At KIT, we also operate FLUTE (Ferninfrarot Linac- und Test-Experiment), a new compact versatile linear accelerator as a test facility for novel techniques and diagnostics. There, EO diagnostics will be implemented to open up possibilities to evaluate and compare new techniques for longitudinal bunch diagnostics. In this contribution, we will give an overview of results achieved, the current status of the EO diagnostic setups at KARA and FLUTE and discuss future prospects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB293

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 17 August 2021

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MOPAB300

Description of the Beam Diagnostics Systems for the SOCIT, SODIT and SODIB Applied Research Stations Based on the NICA Accelerator Complex

detector, controls, diagnostics, radiation

946

A. Slivin, A. Agapov, A.A. Baldin, A.V. Butenko, G.A. Filatov, K.N. Shipulin, E. Syresin, G.N. Timoshenko, A. Tuzikov
JINR, Dubna, Moscow Region, Russia
D.V. Bobrovskiy, A.I. Chumakov, S. Soloviev
MEPhI, Moscow, Russia
I.L. Glebov, V.A. Luzanov
GIRO-PROM, Dubna, Moscow Region, Russia
A.S. Kubankin
BelSU, Belgorod, Russia
T. Kulevoy, Y.E. Titarenko
ITEP, Moscow, Russia

Within the framework of the NICA project an Innovation Block is being constructed. It includes an applied research station for microchips with a package for Single Event Effects (SEE) testing (energy range of 150-500 MeV/n, the SODIT station), an applied research station for testing of decapsulated microchips (ion energy up to 3,2 MeV/n, the SOCIT station), and an applied research station for space radiobiological research and modelling of influence of heavy charged particles on cognitive functions of the brain of small laboratory animals and primates (energy range 500-1000 MeV/n, the SODIB station). The systems for diagnostics and control of the beam characteristics during the certification and adjustment as well as the systems for online diagnostics and control of the beam characteristics of the SOCIT, SODIT and SODIB applied research stations are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB300

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

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MOPAB302

Characterization of the Full Transverse Phase Space of Electron Bunches at ARES

simulation, electron, quadrupole, linac

952

S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, H. Dinter, W. Kuropka, F. Mayet, T. Vinatier
DESY, Hamburg, Germany
R.W. Aßmann
INFN/LNF, Frascati, Italy
S. Jaster-Merz
University of Hamburg, Hamburg, Germany

The ARES linear accelerator at the SINBAD facility (DESY) is dedicated to perform accelerator R&D studies with sub-fs short electron bunches to test novel acceleration techniques and diagnostics devices. Currently, the commissioning of the linac is ongoing and first experiments are being performed. For this, the knowledge of the full phase space of the particle beams is of high interest to, for example, optimize the accelerator performance and identify possible errors in the beam line. Tomographic methods can be used to gain insight into the full 4D transverse phase space and its correlations. Here, simulation results and first experimental preparations of a 4D transverse phase-space tomography of electron bunches at ARES are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB302

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paper received ※ 17 May 2021 paper accepted ※ 16 June 2021 issue date ※ 30 August 2021

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MOPAB310

Vertical Phase Space Measurement Progress at Canadian Light Source

electron, emittance, lattice, synchrotron

963

Y. Yousefi Sigari, D. Bertwistle, M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
M.J. Boland
University of Saskatchewan, Saskatoon, Canada

A key feature of third-generation light sources is their small vertical opening angle, which is difficult to measure experimentally. To reconstruct the vertical phase space, one can scan the beam’s position using X-ray synchrotron radiation (XSR) and a pinhole camera. The XSR diagnostic beamline, operational in the wavelength region of 0.05 - 0.15 nm, in Canadian Light Source (CLS) is qualified to measure the beam position with X-ray radiation. Using the corrector magnets in CLS lattice made of 12 identical double-bend achromats (DBA) cells, vertical iterations can be executed parallel to the beam’s original orbit. The outcomes of this experiment are: 1) the vertical beam positions that are monitored by BPMs, and 2) the X-ray image of the beam that is projected through the pinhole. The bumps were simulated using Matlab Middle Layer (MML) for Accelerator control systems to get an insight of the source point’s position in the XSR’s bending magnet. The simulation shows the position of the source point depends on which corrector sets are chosen.

Poster MOPAB310 [0.328 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB310

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 13 August 2021

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MOPAB314

Surrogate Modeling for MUED with Neural Networks

electron, gun, network, operation

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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MOPAB318

Beam Characterization of Five Electrode ECR Ion Source

emittance, ECR, ECRIS, plasma

980

H.M. Kewlani, S. Gharat, S. Krishnagopal, J.V. Mathew, S.V.L.S. Rao
BARC, Mumbai, India
B. Dikshit, H.M. Kewlani, S. Krishnagopal
Homi Bhbha National Institute (HBNI), DAE, Mumbai, India

A five electrode ECR Ion Source (ECRIS) was developed for the Low Energy High-Intensity Proton Accelerator (LEHIPA) at BARC. The ECRIS is operated at the energy of 50 keV with a beam current of 20 mA. The ECRIS characterization is done for the beam current, beam emittance, and proton fraction in continuous and pulse beam operation. The pulsed beam operation of the ion source starting from 500 µs to 200 ms of pulse on time with a repetition rate of 1 to 10 Hz. The transverse beam emittance measurement is done by using an Allison scanner. The beam emittance characterization experiments are conducted by varying applied microwave power to the plasma, operating gas pressure of plasma and puller voltage. The measured beam emittance is in the range of 0.3 pi.mm. mrad to 0.4 pi.mm. mrad for 50 keV beam. In this paper beam emittance experiment setup and results are discussed.

Poster MOPAB318 [2.496 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB318

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 16 August 2021

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MOPAB320

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

operation, controls, alignment, insertion

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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MOPAB325

Development of Bunch Width Monitor with High Time Resolution for Low Emittance Muon Beam in the J-PARC Muon g-2 / EDM Experiment

emittance, acceleration, linac, laser

1004

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

The J-PARC muon g-2/EDM experiment plans to measure the muon anomalous magnetic moment and electric dipole moment sensitive to new physics with high precision. This experiment uses a novel method using the low-emittance muon beam achieved by cooling and re-acceleration. In the muon linac consisting of four different accelerating cavities, the main cause of the emittance growth is the beam mismatch between the different cavities. Especially for the cavity in the low-beta section (ß=0.08-0.27), the longitudinal acceptance is narrow and beam mismatch has a significant impact. In order to perform beam matching in the low-beta cavity, a new beam monitor that can measure the low-emittance muon beam with high time resolution is required. Therefore, we developed a bunch width monitor (BWM) using a microchannel plate. The time resolution of the BWM was measured to be 40 picoseconds on the test bench using a picosecond pulse laser. It means that the BWM is possible to perform diagnosis with a phase accuracy of 1% for the acceleration phase of 324 MHz. We also evaluated factors that limit the current time resolution. In this presentation, the results of an evaluation of the BWM are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB325

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paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 10 August 2021

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MOPAB340

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

rfq, vacuum, simulation, operation

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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MOPAB346

Broadband Frequency Electromagnetic Characterisation of Coating Materials

GUI, electron, vacuum, site

1076

A. Passarelli, C. Koral, M.R. Masullo
INFN-Napoli, Napoli, Italy
A. Andreone
Naples University Federico II, Napoli, Italy
M. De Stefano
University of Naples, Naples, Italy
V.G. Vaccaro
Naples University Federico II and INFN, Napoli, Italy

In the new generation of particle accelerators and storage rings, collective effects have to be carefully analyzed. In particular, the finite conductivity of the beam pipe walls is a major source of impedance and instabilities. A reliable electromagnetic (EM) characterisation of different coating materials is required up to hundreds of GHz due to very short bunches. We propose two different measurement techniques for an extended frequency characterization: (i) a THz time domain setup based on the signal transmission response of a tailored waveguide to infer the coating EM properties from 100 to 300 GHz or even further*.**. This technique has been tested both on NEG and amorphous Carbon films. (ii) a resonant method, based on dielectric cavities, to evaluate the surface resistance Rs of thin conducting samples at low (GHz) frequencies***. Due to its high sensitivity, Rs values can be obtained for very thin (nanometric) coatings or for copper samples with a laser treated surface, since they have an expected conductivity very close to bulk copper.
*A. Passarelli et al., Phys. Rev. Accel. Beams, v.21, p.103101, 2018
**A. Passarelli et al., Cond. Matter, v.5, p.9, 2020
***A. Andreone et al., Applied Physics Letters, v.91, n.7, p.072512, 2007

Poster MOPAB346 [2.613 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB346

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 26 August 2021

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MOPAB361

Threshold in Filling Failure of RF Cavity Caused by Beam Loading in Multipactor

multipactoring, cavity, simulation, electron

1122

J. Pang
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Y. Dong
Institute of Applied Physics and Computational Mathematics, People’s Republic of China
Y. Du
Institute of Fluid Physics,, China Academy of Engineering Physics, Mianyang, People’s Republic of China

Funding: NSFC
A pulsed RF cavity would be heavily detuned caused by beam loading of multipactor current in the RF filling process. Multipactor zone would be expended by several times than that in static states with assumptions of fixed voltage and no beam loading. The dynamic of multipactor in the RF filling process was simulated by coupling with parameters of external circuit with the developed simulation code, and test in experiments with a parallel-plate resonator. Threshold of RF voltage, which means the lower boundary of peak voltage of multipactor zone, had been quantified with different cavity parameters. When we increased the gap length, the measured threshold became larger due to the ionization in background gas. Then the secondary emission factor would be increased in simulation for consistence with the experiment results. Additionally, some multipactor phenomenon could not be predicted precisely because the simulation code did not take account of ionization. The hysteresis of phase and energy of ionization electrons would be a new driving factor for the growth of multipactor in certain conditions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB361

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paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 10 August 2021

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MOPAB362

Atomistic Modeling of the Coupling Between Electric Fields and Bulk Plastic Deformation in Rf Structures

simulation, coupling, feedback, framework

1125

S. Bagchi, D. Perez
LANL, Los Alamos, New Mexico, USA

Funding: LANL-LDRD
A notable bottleneck in achieving high-gradient RF technology is dictated by the onset of RF breakdown. While bulk mechanical properties are known to significantly affect breakdown propensity, the underlying mechanisms coupling RF fields to bulk plastic deformation in experimentally relevant thermo-electrical loading conditions remain to be identified at the atomic scale. Here, we present results of large-scale molecular dynamics simulations (MD) to investigate possible modes of coupling. We consider the activation of Frank-Read (FR) sources, which leads to dislocation multiplication, under the action of bi-axial thermal stresses and surface electric-field. With a charge-equilibration formalism incorporated in a classical MD model, we show that a surface electric field acting on an either preexisting or dislocation-induced surface step, can generate a long-range resolved shear stress field inside the bulk of the sample. We investigate the feedback between step growth following dislocation emission and subsequent activations of FR sources and discuss the regimes of critical length-scales and densities of dislocations, where such a mechanism could promote RF breakdown precursors.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB362

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 19 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, operation, 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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MOPAB383

Pressure Test for Large Grain and Fine Grain Niobium Cavities

cavity, niobium, SRF, FEM

1173

M. Yamanaka, T. Dohmae, H. Inoue, T. Saeki, K. Umemori, Y. Watanabe, K. Yoshida
KEK, Ibaraki, Japan
K. Enami
Tsukuba University, Ibaraki, Japan

The pressure test was performed using a fine grain (FG) and a large grain (LG) niobium cavities. The cavity is 1.3 GHz 3-cell TESLA-like shape. The cavity was housed in a steel vessel. Water is supplied into the vessel and the cavity outside is pressurized. The applying pressure and the natural frequency of cavity were measured during the pressure test. The FG and LG cavities were deformed greatly and the pressure dropped suddenly at 3.4 MPa and 1.6 MPa, respectively. The frequency shifted up to 3.4 MHz and 1.3 MHz, respectively. There was no leak after the pressure test, so the cavity did not rupture under above pressure. The result of the pressure at LG cavity is less half than that of the FG cavity. We calculated the stress distribution in the structure by applying outer water pressure using a FEM. The maximum stress at cell when above test pressure is applied, are 146 MPa in FG and 73 MPa in LG, respectively. These stresses are similar to tensile strength of niobium specimen measure by ourselves. The result of pressure tests agrees well with the calculation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB383

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

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MOPAB392

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

cavity, operation, target, simulation

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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MOPAB394

Preliminary BCP Flow Field Investigation by CFD Simulations and PIV in a Transparent Model of a SRF Elliptical Low Beta Cavity

cavity, simulation, SRF, laser

1204

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

Standard vertical Buffered Chemical Polishing (BCP) is one of the main surface treatment for Superconducting Radiofrequency (SRF) cavities. A finite element Computational Fluid Dynamic (CFD) model has been developed. Uncertainties in the solution of fluid simulations are not negligible due to the complex geometry of a SRF cavity; thus without an experimental validation, results from this type of simulations cannot be confidently used to improve the process. To this aim, an experimental study was started to investigate the fluid dynamics of the BCP process by means of Particle Image Velocimetry (PIV) technique. Similitude on Reynolds number and Refractive Index Matching (RIM) technique were also implemented to replace the dangerous BCP mixture with a glycerine-water mixture. The paper describes the preliminary results from simulations and experiment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB394

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

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MOPAB396

Measurements of Magnetic Field Penetration in Superconducting Materials for SRF Cavities

cavity, SRF, solenoid, accelerating-gradient

1208

I.H. Senevirathne, J.R. Delayen, A.V. Gurevich
ODU, Norfolk, Virginia, USA
J.R. Delayen, A-M. Valente-Feliciano
JLab, Newport News, Virginia, USA

Funding: This work is supported by NSF Grants PHY-1734075 and PHY-1416051, and DOE Award DE-SC0010081 and DE-SC0019399
Superconducting radiofrequency (SRF) cavities used in particle accelerators operate in the Meissner state. To achieve high accelerating gradients, the cavity material should stay in the Meissner state under high RF magnetic field without penetration of vortices through the cavity wall. The field onset of flux penetration into a superconductor is an important parameter of merit of alternative superconducting materials other than Nb which can enhance the performance of SRF cavities. There is a need for a simple and efficient technique to measure the onset of field penetration into a superconductor directly. We have developed a Hall probe experimental setup for the measurement of the flux penetration field through a superconducting sample placed under a small superconducting solenoid magnet which can generate magnetic fields up to 500 mT. The system has been calibrated and used to measure different bulk and thin film superconducting materials. This system can also be used to study SIS multilayer coatings that have been proposed to enhance the vortex penetration field in Nb cavities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB396

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021

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MOPAB401

In-Situ EXAFS Investigations of Nb-Treatments in N₂, O₂ and N₂-O₂ Mixtures at Elevated Temperatures

vacuum, site, niobium, cavity

1214

P. Rothweiler, B. Bornmann, J. Klaes, D. Lützenkirchen-Hecht, R. Wagner
University of Wuppertal, Wuppertal, Germany

Funding: We gratefully acknowledge financial support by the German Federal Ministry of Education and Research (BMBF) under project No. 05H18PXRB1.
Smooth polycrystalline Nb metal foils were treated in dilute gas atmospheres using a temperature of 900 °C. Transmission mode X-ray absorption spectroscopy (EX-AFS) at the Nb K-edge was used to investigate changes in the atomic short-range order structure of the bulk Nb-material in-situ. The experiments were performed in a dedicated high-vacuum cell that allows treatments in a dilute gas atmosphere and temperatures of up to 1200 °C. Typical treatments include (i) pre-heating at 900 °C under high-vacuum, (ii) gas exposure at the desired pressure and temperature, and (iii) cooldown to room temperature under vacuum. EXAFS data were collected during the entire procedure with a time resolution of 1 s. For the treatments in N₂ at T = 900°C, the data show subtle changes in the Nb-EXAFS, that are compatible with N-doping of the bulk Nb, and the results suggest Nb uptake on octahedral interstitial sites. However, even a small O2-partial pressure leads to distinct oxidation of the Nb. The results will be discussed in more detail in the presentation.

Poster MOPAB401 [2.032 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB401

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

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MOPAB409

FLUKA Simulations of ²²⁵Ac Production Using Electron Accelerators: Validation Through Comparison with Published Experiments

electron, target, radiation, photon

1226

T.V. Szabo, I.C. Moraes
CNPEM, Campinas, SP, Brazil
F.A. Bacchim Neto
LNLS, Campinas, Brazil
P.V. Guillaumon
USP/LAL, Sao Paulo, Brazil
H.B. de Oliveira
IPEN, São Paulo, Brazil

Targeted Alpha Therapy (TAT) is an active area of study worldwide. This technique has shown a potential in nuclear medicine to treat metastatic disease by alpha particles that deposit energy in small regions nearby cancer cells. Ac-225 is an important alpha-emitting that can be used for cancer TAT. This radioisotope shows good potential for medical applications, therefore is important to study ways of increase its production and availability. One possible path for the Ac-225 product is to radiate a radium target (Ra-226) on a linear electron accelerator (LINAC). Isotope production studies could be implemented using computational tools. In this work, Monte Carlo simulations with FLUKA code were performed and compared to experimental results *. We studied Ac-225 production by photonuclear reactions using a 24 MeV electron beam LINAC hitting a tungsten electron-photon converter. Different energies and geometries were also simulated to obtain optimal production conditions. The specific activity values obtained with simulations had a good agreement with published experimental results.
* MASLOV, O., et. al. Preparation of 225Ac by 226Ra(g, n) photonuclear reaction on an mt25 microtron. Radiochemistry

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB409

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021

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MOPAB411

Quantifying DNA Damage in Comet Assay Images Using Neural Networks

network, proton, software, radiation

1233

S.J.K. Dhinsey, T. Greenshaw, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J.L. Parsons
Cancer Research Centre, University of Liverpool, Liverpool, United Kingdom
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1.
Proton therapy for cancer treatment is a rapidly growing field and increasing evidence suggests it induces more complex DNA damage than photon therapy. Accurate comparison between the two treatments requires quantification of the DNA damage the cause, which can be assessed using the Comet Assay. The program outlined here is based on neural network architecture and aims to speed up analysis of Comet Assay images and provide accurate, quantifiable assessment of the DNA damage levels apparent in individual cells. The Comet Assay is an established technique in which DNA fragments are spread out under the influence of an electric field, producing a comet-like object. The elongation and intensity of the comet tail (consisting of DNA fragments) indicate the level of damage incurred. Many methods to measure this damage exist, using a variety of algorithms. However, these can be time consuming, so often only a small fraction of the comets available in an image are analysed. The automatic analysis presented in this contribution aims to improve this. To supplement the training and testing of the network, a Monte Carlo model will also be presented to create simulated comet assay images.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB411

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 16 August 2021

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MOPAB414

A Novel Facility for Cancer Therapy and Biomedical Research with Heavy Ions for the South East European International Institute for Sustainable Technologies

synchrotron, extraction, injection, radiation

1244

S. Damjanovic, P. Grübling, H. Schopper
SEEIIST, Geneva, Switzerland
U. Amaldi, E. Benedetto, M. Sapinski
TERA, Novara, Italy
E. Benedetto, G. Bisoffi, M. Dosanjh, M. Sapinski, M. Vretenar
CERN, Meyrin, Switzerland
G. Bisoffi
INFN/LNL, Legnaro (PD), Italy
S. Damjanovic, M. Durante, P. Foka, C. Graeff
GSI, Darmstadt, Germany
Th. Haberer
HIT, Heidelberg, Germany
S. Rossi
CNAO Foundation, Milan, Italy
H.J. Specht
Universität Heidelberg, Heidelberg, Germany

The South East European International Institute for Sustainable Technologies (SEEIIST) proposes the construction of a major joint Research Infrastructure in the region, to rebuild cooperation after the recent wars and overcome lasting consequences like technology deficits and brain drain, having at its core a facility for cancer therapy and biomedical research with heavy ions. Beams of ions like Carbon are an advanced way to irradiate tumours but more research is needed, while the higher investment costs than for other radiation treatments have so far limited the European facilities to only four. This initiative aims at being strongly innovative, beyond the existing European designs. While the initial baseline relies on a conservative warm-magnet synchrotron, superconducting magnets for an advanced version of the synchrotron and for the gantry are being developed, with a potential for reductions in size, cost, and power consumption. Both warm and superconducting designs feature high beam intensity for faster treatment, and flexible extraction for novel treatment methods. A novel injector linac has the potential for producing radioisotopes in parallel with synchrotron injection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB414

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paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 22 August 2021

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MOPAB418

Tracking and LET Measurements with the MiniPIX-TimePIX Detector for 60 MeV Clinical Protons

detector, radiation, proton, instrumentation

1260

J.S.L. Yap, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N.J.S. Bal
NIKHEF, Amsterdam, The Netherlands
M.D. Brooke
University of Oxford, Oxford, United Kingdom
C. Granja, C. Oancea
ADVACAM s.r.o, Prague, Czech Republic
A. Kacperek
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
C.P. Welsch, J.S.L. Yap
The University of Liverpool, Liverpool, United Kingdom

Funding: EU FP7 grant agreement 215080, H₂020 Marie Sklodowska-Curie grant agreement No 675265, OMA - Optimization of Medical Accelerators and the Cockcroft Institute core grant STGA00076-01.
Recent advancements in accelerator technology have led the rapid emergence of particle therapy facilities worldwide, affirming the need for enhanced characterisation methods of radiation fields and radiobiological effects. The Clatterbridge Cancer Centre, UK operates a 60 MeV proton beam to treat ocular cancers and facilitates studies into proton induced radiobiological responses. Accordingly, an indicator of radiation quality is the linear energy transfer (LET), a challenging physical quantity to measure. The MiniPIX-Timepix is a miniaturised, hybrid semiconductor pixel detector with a Timepix ASIC, enabling wide-range measurements of the deposited energy, position and direction of individual charged particles. High resolution spectrometric tracking and simultaneous energy measurements of single particles enable the beam profile, time, spatial dose mapping and LET (0.1 to >100 keV/µm) to be resolved. Measurements were performed to determine the LET spectra in silicon, at different positions along the Bragg Peak (BP). We discuss the experimental setup, preliminary results and applicability of the MiniPIX for clinical environments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB418

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paper received ※ 18 May 2021 paper accepted ※ 23 July 2021 issue date ※ 25 August 2021

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TUXA03

Progress in Mastering Electron Clouds at the Large Hadron Collider

simulation, electron, operation, luminosity

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.

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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, operation, 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).

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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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TUXA05

Measurements of Beam-Beam Interactions in Gear-Changing Collisions in DESIREE

collider, beam-beam-effects, HOM, framework

1283

E.A. Nissen
JLab, Newport News, Virginia, USA
A. Källberg, A. Simonsson
Stockholm University, Stockholm, Sweden

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript.
In this work, we perform measurements on the interactions of colliding beams in a gear-changing system. Gear-changing was first demonstrated in DESIREE in May of 2020 and showed several promising avenues to measure beam-beam effects. DESIREE has a unique collision scheme where the beams are moving in the same direction, which provides for unique interactions. This experiment used a 4 on 3 gear changing system with one bucket in each ring left empty, this allows us to see the bunch profile while undergoing collisions. We then measured the bunch length over time and used a Fourier transform to extract longitudinal evolution data and compared it to baseline data of uncollided beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA05

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paper received ※ 21 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021

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TUXC06

Visualizing Lattice Dynamic Behavior by Acquiring a Single Time-Resolved MeV

electron, lattice, laser, detector

1311

X. Yang, T.V. Shaftan, V.V. Smaluk, J. Tao, L. Wu, Y. Zhu
BNL, Upton, New York, USA
W. Wan
ShanghaiTech University, Shanghai, People’s Republic of China

We explore the possibility of visualizing the lattice dynamic behavior by acquiring a single time-resolved MeV UED image. Conventionally, multiple UED shots with varying time delays are needed to map out the entire dynamic process. The measurement precision is limited by the timing jitter between the pulses of laser pump and UED probe. We show that, by converting the longitudinal time of an electron bunch to the transverse position of a Bragg peak on the detector, one can obtain the full lattice dynamic process in a single electron pulse. We propose a novel design of a time-resolved UED with the capability of capturing a wide range of dynamic features in a single diffraction image. The work presented here is not only an extension of the ultrashort-pulse pump/long-pulse probe scheme being used in transient spectroscopy studies for decades but also advances the capabilities of MeV UED for future applications with tunable electron probe profile and detecting time range with femtosecond resolution. Furthermore, we present numerical simulations illustrating the capability of acquiring a single time-resolved diffraction image based on the case-by-case studies of lattice dynamic behavior.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC06

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paper received ※ 14 May 2021 paper accepted ※ 28 July 2021 issue date ※ 31 August 2021

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TUXC08

Simulation and Beam Experiments of a Multi-Harmonics Buncher in SSC-Linac

linac, simulation, rfq, heavy-ion

1319

Q.Y. Kong, H. Du, P. Jin, L. Jing, X.N. Li, Z.S. Li, Zh. Liu, J.W. Xia, X. Yin, Y. Zhang
IMP/CAS, Lanzhou, People’s Republic of China

Funding: This work was supported by the National Natural Science Foundation of China(No. 11375243) and Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06G373).
A compact dual-gap Multi-Harmonics Buncher has been successfully used at the SSC-Linac, a linear accelerator dedicates to beam injection into SSC in HIRFL. SSC-Linac operates at 53.667MHz, which is forth time of the RF frequency of the SSC. In order to increase the longitudinal capture efficiency, and enhance the current out of SSC, an independent MHB(Multi-Harmonics Buncher) had been installed into the LEBT of SSC-Linac. The fundamental frequency of the MHB is 13.417MHz. The buncher adopts the mechanical structure of dual-gap and sawtooth waveform is generated by multi-harmonics synthetic technology. Beam performance simulation with MHB have been done with code BEAMPATH. Besides, 84Kr¹⁴⁺ beam has been bunched successfully using the MHB in our experiments, the maximum bunch efficiency of 86.1% has been measured in experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC08

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paper received ※ 31 May 2021 paper accepted ※ 12 July 2021 issue date ※ 11 August 2021

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TUPAB063

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

injection, controls, operation, 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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TUPAB069

The Sabina Terahertz/Infrared Beamline at SPARC-Lab Facility

radiation, electron, photon, laser

1525

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

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

Poster TUPAB069 [0.884 MB]

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

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

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TUPAB071

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

undulator, FEL, radiation, electron

1528

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

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

Poster TUPAB071 [1.978 MB]

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

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

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TUPAB086

FLASH2020+ Plans for a New Coherent Source at DESY

FEL, laser, electron, undulator

1581

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

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

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

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

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TUPAB089

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

FEL, laser, electron, radiation

1589

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

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

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

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

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TUPAB110

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

electron, FEL, klystron, cavity

1644

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

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

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

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

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TUPAB115

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

FEL, electron, undulator, operation

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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TUPAB131

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

radiation, electron, bunching, background

1696

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

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

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

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

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TUPAB141

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

laser, plasma, electron, photon

1713

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

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

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

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

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TUPAB146

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

plasma, laser, injection, electron

1728

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

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

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

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

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TUPAB148

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

plasma, electron, wakefield, focusing

1736

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

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

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

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

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TUPAB159

Awake Run 2 at CERN

plasma, electron, proton, acceleration

1757

E. Gschwendtner
CERN, Meyrin, Switzerland

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

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

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

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TUPAB160

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

electron, plasma, proton, simulation

1761

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

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

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

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

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TUPAB174

Basic Design Study for Disk-Loaded Structure in Muon LINAC

accelerating-gradient, acceleration, linac, impedance

1801

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

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

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

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

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TUPAB178

Recommissioning of the CRYRING@ESR Electron Cooler

electron, target, acceleration, operation

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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TUPAB181

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

electron, space-charge, timing, emittance

1827

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

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

Poster TUPAB181 [3.699 MB]

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

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

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TUPAB182

The Electron Cooling for High Energy

electron, high-voltage, gun, collider

1831

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

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

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

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

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TUPAB210

Construction Status of the COMET Experimental Facility

target, solenoid, proton, radiation

1907

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

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

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

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

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TUPAB219

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

emittance, betatron, optics, factory

1935

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

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

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

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

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TUPAB222

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

operation, 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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TUPAB228

IOTA Run 2 Beam Dynamics Studies in Nonlinear Integrable Systems

optics, octupole, lattice, simulation

1964

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

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

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

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

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TUPAB233

Diffusive Models for Nonlinear Beam Dynamics

hadron, collider, dynamic-aperture, beam-losses

1976

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

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

Poster TUPAB233 [0.574 MB]

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

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

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TUPAB234

Exploring Accelerators for Intense Beams with the IBEX Paul Trap

octupole, lattice, quadrupole, simulation

1980

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

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

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

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

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TUPAB247

Influence of the Profile of the Dielectric Structure on the Electric Fields Excited by a Laser in Dielectric Accelerators Based on Chip

electron, acceleration, laser, simulation

2026

A. Vasyliev, O.O. Bolshov, K. Galaydych, A.I. Povrozin, G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine

Funding: The National Research Foundation of Ukraine, program "Leading and Young Scientists Research Support" (project # 2020.02/0299).
To provide experimental researches at the NSC KIPT theoretical studies and computations of the electron acceleration in a dielectric laser accelerator have been carried out. Laser accelerator consists of two periodic quartz structures on diffraction gratings or Chips, symmetrically located along both sides of the vacuum accelerating channel. Using PIC numerical simulations, electromagnetic fields excited by laser radiation with a wavelength of 800 nm in dielectric laser accelerators were investigated. The influence of the shape and depth of the profile of diffraction gratings or Chip structures on the distribution of the electric field in the interaction space has been studied. For modeling, different types of profiles were taken, both in serial and a unique structure. In consequence of the analysis of the obtained results, estimated efficiency of acceleration was defined for each type of profile. The rectangular profile of the diffraction grating with the maximum accelerating gradient was selected as optimal for the next experiments.

Poster TUPAB247 [1.195 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB247

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 11 August 2021

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TUPAB256

Investigation of Damping Effects of the Crab Cavity Noise Induced Emittance Growth

emittance, simulation, impedance, cavity

2054

N. Triantafyllou, L.R. Carver, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou, N. Triantafyllou
CERN, Meyrin, Switzerland
L.R. Carver
ESRF, Grenoble, France
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

Crab cavities will be installed at the two main interaction points (IP1 and IP5) of the High Luminosity LHC (HL-LHC) in order to minimize the geometric reduction of the luminosity due to the crossing angle. Two prototype crab cavities have been installed into the SPS machine and were tested with a proton beam in 2018, to study the expected emittance growth induced by RF noise. The measured emittance growth was found to be a factor 2-3 lower than predicted from the available analytical and computational models. Damping mechanisms from the transverse impedance, which is not included in the available theories, are studied as a possible explanation for the observed discrepancy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB256

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

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TUPAB277

Bunch Length Characterizations for the Solaris Injector LINAC

radiation, linac, electron, diagnostics

2117

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

During 2020 the first characterization of bunch length and bunch profile in the Solaris injector LINAC has been performed since the start of its operation. In absence of more sophisticated bunch length diagnostics, we have adopted an inversion algorithm applied to beam energy spectra. In practice, the method applies a transformation matrix which maps the particle energy into the particle longitudinal coordinate along the bunch. The construction of this matrix is made analytically, based on the solution of the Liouville equation for the study of the longitudinal beam dynamics. The analytic approach has been benchmarked with experimental measurements of the beam properties along the machine and cross-checked with other tools, as particle tracking and/or beam optics codes. The final results are presented. Moreover, a new diagnostic station at the end of the LINAC has been installed which will host experiments of coherent radiation emission that will be used to confirm the validity of our observations. Preliminary simulations of the coherent spectra are finally reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB277

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 12 August 2021

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TUPAB282

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

diagnostics, synchrotron, operation, 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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TUPAB284

BPM for the High Energy Beam Transport Line of MINERVA Project at SCK•CEN

linac, instrumentation, electron, proton

2143

H. Kraft, L. Perrot
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

This paper presents the status of developments concerning button type BPM. Results of our analytical model BPMOK will compare the measurements done at IPHI facility at CEA-Saclay and GANIL/SPIRAL2 in Caen. The measurements aims to compare the response of the analytical model depending on beam positions, sizes, intensities and energies. BPMOK is validated to predict BPM responses in order to make parametric studies. Starting from already existing BPM built for the MINERVA LINAC, the analytical model is used to design the BPM for the HEBT.

Poster TUPAB284 [1.475 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB284

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paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021

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TUPAB289

Towards Hysteresis Aware Bayesian Regression and Optimization

ISAC, target, controls, operation

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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TUPAB297

Data Archive System for Superconducting RIKEN Linear Accelerator at RIBF

controls, EPICS, network, cyclotron

2178

A. Uchiyama, N. Fukunishi, M. Kidera, M. Komiyama
RIKEN Nishina Center, Wako, Japan

At RIKEN Nishina Center, superconducting RIKEN Linear Accelerator (SRILAC) was newly installed at downstream of existing accelerator and upgraded for the search experiments of super-heavy-elements with atomic numbers of 119 and higher. For the data archiving and the data visualization in RI Beam Factory (RIBF) project, we have utilized RIBFCAS (RIBF control archive system) since 2009. For the number of archived data point was expected to increase dramatically for SRILAC, we introduced the Archiver Appliance for improvement of the data archiving performance. On the other hand, to realize a user-friendly system about the data visualization, the data of RIBFCAS and the Archiver Appliance should be visualized on the same system. In this system, by implementing a Web application to convert the RIBFCAS data to JSON format, it became possible to unify the data format with the Archiver Appliance and display the data with the same viewer software. In the SRILAC beam commissioning, it became to useful system for finding anomalies and understanding the behavior of superconducting cavity. In this conference, we report the system implementation, developed tool, and the future plan in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB297

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paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 17 August 2021

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TUPAB300

Ion Source Optimization Using Bi-Objective Genetic and Matrix-Profile Algorithm

ion-source, controls, ECR, software

2190

W. Geithner, Z. Andelkovic, O. Geithner, F. Herfurth, V. Rapp
GSI, Darmstadt, Germany
A. Neméth
Atato, Alzenau, Germany
A. Van Benschoten
MPF, Plymouth, Minnesota, USA
F. Wilhelmstötter
emarsys, Vienna, Austria

Employing the local ECR ion source of the FAIR phase 0 ion storage ring CRYRING@ESR, we set up an IT-environment for on-line data processing and applications based on the data available from beam diagnostic instruments and input signals controlling the ion source. As a first proof of principle, we implemented a closed-loop optimization software controller based on bi-objective Genetic Optimization*. As one property for optimization we used the ion beam current measured with a Faraday-cup detector. As second optimization-property we the on-line processed time-resolved signal of the individual ion-source pulses employing the relatively new Matrix-Profile Algorithm** which provides a measure for the shot-by-shot variability of the consecutive pulses. We will report on the status of the data logging framework, the implementation of related software programs and the results of first tests.
* Wilhelmstötter, F.: Jenetics advanced genetic algorithm, online http://jenetics.io
** Matrix Profile Foundation. Homepage, online https://github.com/matrix-profile-foundation

Poster TUPAB300 [5.485 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB300

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paper received ※ 01 June 2021 paper accepted ※ 21 June 2021 issue date ※ 16 August 2021

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TUPAB317

Benchmarking of the Radiation Environment Simulations for CMS Experiment at LHC

radiation, simulation, detector, neutron

2235

I.L. Azhgirey, I.A. Kurochkin, A.D. Riabchikova
IHEP, Moscow Region, Russia
D. Bozzato, A.E. Dabrowski, P. Kicsiny, S. Mallows, J. Wanczyk
CERN, Geneva, Switzerland

Radiation Simulations group of the Beam Radiation Instrumentation and Luminosity Project of the CMS experiment provide for CMS radiation environment and radiation effects simulation and benchmarking of these calculations with CMS data and other data from LHC measuring devices. We present some results of such benchmarking and the reliability analysis of the simulation procedures for radiation environment calculations at the LHC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB317

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 29 August 2021

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TUPAB320

Physical Design of the Radiation Shielding for the CMS Experiment at LHC

radiation, simulation, detector, shielding

2246

I.L. Azhgirey, I.A. Kurochkin, A.D. Riabchikova
IHEP, Moscow Region, Russia
D. Bozzato, A.E. Dabrowski, S. Mallows
CERN, Meyrin, Switzerland

The design of the radiation shielding for the CMS experiment at the LHC requires a simulation of the radiation environment using a model of the CMS experimental setup, accelerator components and the experimental hall infrastructure. The radiation simulations are used to optimise the design of the CMS detectors components and also the interface of the CMS detector with LHC accelerator. The Beam Radiation Instrumentation and Luminosity Project of CMS is responsible for giving important input into the optimisation and upgrade of radiation shielding used in CMS and also the radiation environment simulations software infrastructure. This contribution describes the organization of this work, the simulation software environment used for this part of CMS experiment activity and recent radiation simulation results used to optimise the forward shielding for CMS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB320

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 10 August 2021

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TUPAB326

Injection Optimization and Study of XiPAF Synchrotron

injection, simulation, synchrotron, proton

2264

X.Y. Liu, X. Guan, Y. Li, M.W. Wang, X.W. Wang, H.J. Yao, W.B. Ye, H.J. Zeng, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, M.C. Wang, Z.M. Wang, Y. Yang, M.T. Zhao
NINT, Shannxi, People’s Republic of China

The synchrotron of XiPAF (Xi’an 200MeV proton application Facility) is a compact proton synchrotron, which using H^- stripping injection and phase space painting scheme. Now XiPAF is under commissioning with some achievements, the current intensity after injection reach 43mA, the corresponding particle number is 2.3·10¹¹, and the injection efficiency is 57%. The simulation results by PyOrbit show that the injection efficiency is 77%. In this paper, we report how the injection intensity and efficiency were optimized. We analyzed the difference between simulation and experiments, and quantitatively investigate the factors affecting injection efficiency through experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB326

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

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TUPAB344

Evaluation of Anisotropic Magnetoresistive (AMR) Sensors for a Magnetic Field Scanning System for SRF Cavities

cavity, SRF, niobium, MMI

2304

I.P. Parajuli, G. Ciovati, J.R. Delayen, A.V. Gurevich
ODU, Norfolk, Virginia, USA
G. Ciovati, J.R. Delayen
JLab, Newport News, Virginia, USA

Funding: Work supported by NSF Grant 100614-010. G. C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the significant causes of residual losses in superconducting radio-frequency (SRF) cavities is trapped magnetic flux. The flux trapping mechanism depends on many factors that include cool-down conditions, surface preparation techniques, and ambient magnetic field orientation. Suitable diagnostic tools are not yet available to quantitatively correlate such factors’ effect on the flux trapping mechanism. A magnetic field scanning system (MFSS) consisting of AMR sensors, fluxgate magnetometers, or Hall probes is recently commissioned to scan the local magnetic field of trapped vortices around 1.3 GHz single-cell SRF cavities. In this contribution, we will present results from sensitivity calibration and the first tests of AMR sensors in the MFSS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB344

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 29 August 2021

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TUPAB348

Magnetron R&D for High Efficiency CW RF Sources for Industrial Accelerators

injection, GUI, cavity, MMI

2318

H. Wang, K. Jordan, R.M. Nelson, R.A. Rimmer, S.O. Solomon
JLab, Newport News, Virginia, USA
B.R.L. Coriton, C.P. Moeller, K.A. Thackston
GA, San Diego, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and DOE OS/HEP Accelerator Stewardship award 2019-2021.
The scheme of using high-efficiency magnetrons to drive radiofrequency accelerators has been demonstrated at 2450 MHz in CW mode *. Magnetron test stands at JLab and GA have been set up to further test the noise figure and the locking speed of the injection phase-lock method. For higher power applications, power combining experiments using a TM010 cavity-type combiner and a magic tee for the binary combiner while using a single clean injection signal has been carried out at 2450 MHz. The frequency pulling effect between the magnetron and a low-Q cavity has been shown to enhance the frequency locking bandwidth compared to the injection phase-lock alone. The principle has been studied by the equivalent circuit simulation, analytical model, and finally confirmed experimentally on the magnetrons. Due to the pandemic delay in 2020, the equivalent high power tests using a 75kW, 915MHz industrial magnetron will be done in 2021 and will be reported in a future paper.
* H. Wang, et al, Magnetron R&Ds for High-Efficiency CW RF Sources of Particle Accelerators, WEXXPLS1, proceedings of IPAC 2019, Melbourne, Australia, May 19 -24, 2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB348

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paper received ※ 22 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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TUPAB357

Development of the X-Band Megawatt-Class Coaxial Magnetrons

linac, radiation, high-voltage, electron

2346

J.Y. Liu, H.B. Chen, Y.S. Han, J. Shi, C.-X. Tang, C.J. Wang, J. Wang, H. Zha
TUB, Beijing, People’s Republic of China

X-band coaxial magnetrons are preferred for industrial and medical accelerators owing to the compact size, low cost and high efficiency. A conditioning and high power test stand for X-band magnetrons has been built in Tsinghua University. Two X-band magnetrons named "MGT-1#" and "MGT-2#" were tested at this stand. The maximum anode currents of both magnetrons reached 100 A after the conditioning process. Maximum peak output power of 1.71 MW and 1.89 MW was achieved for "MGT-1#" and "MGT-2#", respectively. The efficiencies of the two magnetrons are both about 50%.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB357

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 28 August 2021

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TUPAB359

Magnetic Field Measurement and Beam Performance Test of Ceramics Chamber with Integrated Pulsed Magnet at KEK-PF

vacuum, survey, kicker, dipole

2352

Y. Lu
Sokendai, Ibaraki, Japan
K. Harada, Y. Kobayashi, C. Mitsuda, S. Nagahashi, T. Nogami, T. Obina, R. Takai, H. Takaki, T. Uchiyama, A. Ueda
KEK, Ibaraki, Japan

An air-core magnet named Ceramics Chamber with integrated Pulsed Magnet(CCiPM) is being developed at the photon factory of KEK(KEK-PF), which will have several applications for the future light source. One prototype has been developed as a dipole kicker, whose bore is only 30mm. Due to the type and structure, it’s expected to have strong magnetic field and high repetition rate. After finishing the offline measurement of magnetic field and evaluation of vacuum tightness, the CCiPM was installed in the beam transport-dump line of PF to have an online beam performance and durability test. The results of the magnetic field measurement and beam performance test will be reviewed.

Poster TUPAB359 [1.164 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB359

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 16 August 2021

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TUPAB364

Dipole CR FAIR

dipole, HOM, simulation, storage-ring

2367

K.K. Riabchenko, A.Yu. Pakhomov, T.V. Rybitskaya, A.A. Starostenko, A.S. Tsyganov, K.V. Zhiliaev
BINP SB RAS, Novosibirsk, Russia

The design of CR dipole magnets (24+2 pieces) for the FAIR project in Germany began in 2014 at BINP. CR is a special storage ring where the main emphasis is placed on efficient stochastic pre-cooling of intense beams of stable ions, rare isotopes, or antiprotons. This type of magnet is an iron-based electromagnet with a straight pole, sector form is realized by cutting ends. The maximum field value is 1.6 T. The integrated over the length of the magnet field quality as a function of radius is dBl/Bl = ± 10^-4 with 190 mm good field region as required from the beam dynamics simulations. This challenging field quality is necessary mainly for precise experiments with ion beam in the ISO regime. Below 1.6 T the value dBl/Bl can be higher with a linear approximation up to ± 2.5× 10^-4 at the field level of 0.8 T. The first prototype has been manufactured at the end of 2020. Here we describe features of the dipole, 3D calculations, and measurements of the magnetic field.

Poster TUPAB364 [1.587 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB364

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paper received ※ 09 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021

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TUPAB396

The Thermal Outgassing Rate of Materials Used in Vacuum Systems

vacuum, diagnostics, cathode, radiation

2447

A.M. Semenov
BINP & NSTU, Novosibirsk, Russia
A. Burdakov, A.A. Krasnov, B.P. Tolochko, A.V. Varand
BINP SB RAS, Novosibirsk, Russia
S.R. Ivanova
GPI, Moscow, Russia
A.A. Krasnov
NSU, Novosibirsk, Russia
M.A. Mikhailenko
ISSCM SB RAS, Novosibirsk, Russia
A.A. Shoshin
Budker INP & NSU, Novosibirsk, Russia

There are many rarely used materials in vacuum systems that are poorly investigated in terms of vacuum properties. For example, phosphors, scintillating materials, ferrites, various adhesives, etc. In addition, new organic materials are being developed with mechanical properties similar to those of conventional steel. The use of such materials is very promising in vacuum technology. This article presents the thermal degassing performance of several rarely used materials and promising materials for vacuum applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB396

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paper received ※ 18 May 2021 paper accepted ※ 31 August 2021 issue date ※ 20 August 2021

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TUPAB409

FLUKA and Geant4 Monte Carlo Simulations of a Desktop, Flat Panel Source Array for 3D Medical Imaging

photon, simulation, electron, detector

2483

T. Primidis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T. Primidis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
V. Soloviev
Adaptix Imaging, Didcot, United Kingdom

Funding: Funded by the Accelerators for Security, Healthcare and Environment CDT from the United Kingdom Research and Innovation Science and Technology Facilities Council, reference ID ST/R002142/1
Digital tomosynthesis (DT) is a 3D imaging modality with a lower cost and lower dose than computed tomography. A DT system made of a flat panel array with 45 X-ray sources, but compact enough to fit on the desktop is near market realisation by the company Adaptix Ltd. This work presents a framework of FLUKA and Geant4 Monte Carlo (MC) simulations of the Adaptix system including the X-ray beam generation and the final image quality. The results show that MC methods offer an insight into the performance details of such an innovative device at different levels between the X-ray emitter array and the detector. As such, a large portion of the design and optimisation of such novel X-ray imaging systems can be done with a single toolkit. Finally, the modularity of the approach allows other tools to be imported at various steps within the framework and thus provide answers to questions that cannot be addressed by general-purpose MC codes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB409

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 24 August 2021

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TUPAB410

Finite Element Analysis and Experimental Validation of Low-Pressure Beam Windows for XCET Detectors at CERN

Windows, detector, photon, background

2487

J. Buesa Orgaz, M. Brugger, G. Romagnoli, O. Sacristan De Frutos, F. Sanchez Galan
CERN, Meyrin, Switzerland

In the framework of the renovation and consolidation of experimental areas at CERN, a low-pressure design beam superimposed windows (250 µm Mylar and 150 µm polyethylene) for the Threshold Cherenkov counters (XCET) has been modelled and verified for its implementation. The XCET is a detector used to count the number of selected charged particles in the beam by adjusting the pressure that leads to the emission of Cherenkov photons only above certain pressure threshold. Simultaneously, the charged particles pass from a vacuum environment to the pressurized refractive gas vessel through a solid interface. Minimal material in this solid interface is therefore crucial to avoid interactions of the low-energy particles which may lead to beam intensity loss or background production. Hence, thin and low-density materials are required to mitigate multiple scattering and energy loss of the incoming particles while still allowing the needed pressures inside the counter vessel. A XCET validation methodology was conducted using Finite Element Analysis (FEA), followed by experimental validations performing burst pressure tests and using Digital Image Correlation (DIC).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB410

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

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TUPAB413

Rapid Browser-Based Visualization of Large Neutron Scattering Datasets

neutron, scattering, network, detector

2494

D.L. Bruhwiler, K. Bruhwiler, P. Moeller, R. Nagler
RadiaSoft LLC, Boulder, Colorado, USA
C.M. Hoffmann, Z.J. Morgan, A.T. Savici, M.G. Tucker
ORNL, Oak Ridge, Tennessee, USA
A. Kuhn, J. Mensmann, P. Messmer, M. Nienhaus, S. Roemer, D. Tatulea
NVIDIA, Santa Clara, USA

Funding: This work is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0021551.
Neutron scattering makes invaluable contributions to the physical, chemical, and nanostructured materials sciences. Single crystal diffraction experiments collect volumetric scattering data sets representing the internal structure relations by combining datasets of many individual settings at different orientations, times and sample environment conditions. In particular, we consider data from the single-crystal diffraction experiments at ORNL.* A new technical approach for rapid, interactive visualization of remote neutron data is being explored. The NVIDIA IndeX 3D volumetric visualization framework** is being used via the HTML5 client viewer from NVIDIA, the ParaView plugin***, and new Jupyter notebooks, which will be released to the community with an open source license.
* L. Coates et al., Rev. Sci. Instrum. 89, 092802 (2018).
** https://developer.nvidia.com/nvidia-index
*** https://blog.kitware.com/nvidia-index-plugin-in-paraview-5-5

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB413

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paper received ※ 18 May 2021 paper accepted ※ 21 July 2021 issue date ※ 26 August 2021

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WEXB06

Development of an APF IH-DTL in the J-PARC Muon g-2/EDM Experiment

DTL, linac, cavity, focusing

2544

Y. Nakazawa, H. Iinuma
Ibaraki University, Hitachi, Ibaraki, Japan
E. Cicek, N. Kawamura, T. Mibe, M. Yoshida
KEK, Ibaraki, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Otani, N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue, K. Sumi, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
Y. Takeuchi
Kyushu University, Fukuoka, Japan
T. Yamazaki
KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

An inter-digital H-mode drift-tube linac (IH-DTL) is under development in a muon linac at the J-PARC muon g-2/EDM experiment. It accelerates muons from 0.34 MeV to 4.3 MeV at an operating frequency of 324 MHz. The cavity can be miniaturized by introducing the alternative phase focusing (APF) method that enables transverse focusing only with an E-field. The APF IH-DTL cavity was modeled by a three-dimensional field analysis, and the beam dynamics were evaluated numerically. The beam emittance was calculated as 0.316pi and 0.189pi mm mrad in the horizontal and vertical directions, respectively. It satisfies the experimental requirement. Actually, the field error due to the fabrication errors and thermal expansion during operation causes an emittance growth. It was evaluated that the optimized tuners can suppress the emittance growth to less than 10%. In this paper, the detailed design of the APF IH-DTL including the tuner will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB06

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

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WEPAB021

Development and Testing of a Cherenkov Beam Loss Monitor in CLEAR Facility

detector, photon, electron, beam-losses

2640

S. Benitez Berrocal, E. Effinger, W. Farabolini, A. Gilardi, P. Korysko, E. Lima, B. Salvachua, W. Viganò
CERN, Geneva 23, Switzerland
P. Lane
University of Huddersfield, Huddersfield, United Kingdom

Beam Loss Monitors are fundamental diagnostic systems in particle accelerators. Beam losses are measured by a wide range of detectors with excellent results; most of these devices are used to measure local beam losses. However, in some accelerators there is the need to measure beam losses continuously localized over longer distances i.e., several tens of meters. For this reason, a beam loss detector based on long optical fibres is now under study. As part of the design, several simulations, comparing different possible detection scenarios, have been performed in FLUKA and bench-marked with experimental data. An experimental campaign was performed with an electron beam in the CERN Linear Electron Accelerator for Research (CLEAR) in November 2020. The light emitted from the optical fibre was captured using Silicon Photo-Multipliers (SiPM) coupled at each fibre’s end. In this poster, the first results of a beam loss detector based on the capture of Cherenkov photons generated by charged particles inside multimode silica fibres are presented.

Poster WEPAB021 [0.724 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB021

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 31 August 2021

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WEPAB043

Consolidation and Future Upgrades to the CLEAR User Facility at CERN

laser, gun, electron, radiation

2700

L.A. Dyks, P. Korysko
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
P. Burrows
JAI, Oxford, United Kingdom
R. Corsini, S. Curt, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, E. Granados, G. McMonagle, H. Panuganti
CERN, Geneva, Switzerland
W. Farabolini
CEA-DRF-IRFU, France
A. Gilardi
University of Napoli Federico II, Napoli, Italy
K.N. Sjobak
University of Oslo, Oslo, Norway

The CERN Linear Electron Accelerator for Research (CLEAR) at CERN has been operating since 2017 as a dedicated user facility providing beams for a varied range of experiments. CLEAR consists of a 20 m long linear accelerator (linac), able to produce beams from a Cs₂Te photocathode and accelerate them to energies of between 60 MeV and 220 MeV. Following the linac, an experimental beamline is located, in which irradiation tests, wakefield and impedances tudies, plasma lens experiments, beam diagnostics development, and terahertz (THz) emission studies, are performed. In this paper, we present recent upgrades to the entire beamline, as well as the design of future upgrades, such as a dogleg section connecting to an additional proposed experimental beamline. The gain in performance due to these upgrades is presented with a full range of available beam properties documented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB043

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

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WEPAB044

Status of VHEE Radiotherapy Related Studies at the CLEAR User Facility at CERN

electron, radiation, linac, focusing

2704

R. Corsini, W. Farabolini, A. Gilardi
CERN, Geneva, Switzerland
L.A. Dyks, P. Korysko
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
W. Farabolini
CEA-DRF-IRFU, France
A. Gilardi
University of Napoli Federico II, Napoli, Italy
K.N. Sjobak
University of Oslo, Oslo, Norway

Despite the increase in interest in using Very High Energy Electron (VHEE) beams for cancer radiotherapy many unanswered questions in its development remain. The use of test facilities will be an essential tool used to solve these issues. The 200 MeV electron beam from the CERN Linear Accelerator for Research (CLEAR) has been used extensively, in collaboration with several research institutes, to perform dosimetry studies and explore potential applications of VHEE beams to radiotherapy, including the exploitation of the so called FLASH effect. In this paper, we present an overview of past studies with emphasis on the more recent results. We describe methods, techniques and equipment developed at CERN in this framework, and give an outlook on future activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB044

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paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 27 August 2021

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WEPAB048

Design of an Optical Cavity for Generating Intense THz Pulse Based on Coherent Cherenkov Radiation

electron, radiation, cavity, gun

2711

P. Wang, Y. Koshiba, T. Murakami, K. Murakoshi, K. Sakaue, Y. Tadenuma, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

We have been studying terahertz (THz) generation via Cherenkov radiation with high-quality electron beams from a photocathode rf (radio frequency) gun. In our early studies, we have succeeded in the generation of coherent Cherenkov radiation by controlling the tilt of the electron beam using an rf-deflector. For further enhancement, we are planning to stack the THz pulses in an optical cavity. Multi-bunch operation of the rf-gun will generate electron beams with a repetition rate of 119 MHz, and THz pulses as well. These pulses will be accumulated in the cavity for up to 150 pulses. In this conference, we report the design study of the enhancement cavity and discuss the performance of the THz source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB048

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

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WEPAB052

Development of an EO Sampling System for the Analysis of THz Waves Generated by Coherent Cherenkov Radiation

radiation, electron, laser, timing

2718

K. Murakoshi, Y. Koshiba, T. Murakami, K. Sakaue, Y. Tadenuma, P. Wang, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

THz waves, located between microwaves and light waves, have transparency, directionality and fingerprint spectrum of specific materials. Therefore, they are expected to be useful for various applications. We have been studying THz waves generation via Cherenkov radiation with electron beams from a photocathode rf-gun. In our early studies, we have succeeded in the generation of coherent Cherenkov radiation by tilted electron beams using an rf-deflector. Furthermore, we have generated quasi-monochromatic THz waves by spatially modulated electron beams and have succeeded in its measurement by bandpass filters. This study aims to obtain the THz wave form in time domain by electro-optic (EO) sampling, which is an useful detection system for obtaining the information of the electric field and the phase simultaneously with high S/N. In this conference, we report about our probe laser system, results of the time-domain spectroscopy measurement of THz waves by EO sampling, and future prospects.

Poster WEPAB052 [0.861 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB052

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paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021

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WEPAB063

Status of the Polarized Source and Beam Preparation System at MESA

laser, electron, emittance, simulation

2736

S. Friederich, K. Aulenbacher, C. Matejcek
IKP, Mainz, Germany
K. Aulenbacher
HIM, Mainz, Germany
K. Aulenbacher
GSI, Darmstadt, Germany

Funding: This work is supported by the DFG excellence initiative PRISMA+.
The MESA Low-energy Beam Apparatus (MELBA) connects the DC photoemission source STEAM with the injector accelerator MAMBO. MELBA is capable of adjusting the longitudinal phase space for the requirements of the pre-acceleration by using a chopper and buncher while providing small transverse emittances. Measurements of the transverse phase space and longitudinal beam dimension taken at a test setup are presented. These results serve now for further improvements, e.g design changes in our corrector magnets. In addition, the revised MELBA will include two Wien filters and a solenoid for spin manipulation. A double scattering Mott polarimeter for spin diagnostics and a second source for the extraction of high bunch charges is foreseen using a branched off beam line. RF-synchronized laser diodes will be used with infrared wavelength as a driver for the spin-polarized photoemission. In this report we present the latest layout of MELBA and simulation results.

Poster WEPAB063 [1.752 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB063

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paper received ※ 19 May 2021 paper accepted ※ 16 July 2021 issue date ※ 28 August 2021

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WEPAB071

Design and Construction of an Intense Terahertz-Wave Source Based on Coherent Cherenkov Radiation Matched to Circle Plane Wave

radiation, electron, FEL, controls

2751

N. Sei, H. Ogawa
AIST, Tsukuba, Ibaraki, Japan
K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, Y. Takahashi, T. Tanaka
LEBRA, Funabashi, Japan
T. Takahashi
Kyoto University, Research Reactor Institute, Osaka, Japan

Funding: This work was supported by Japan Society for the Promotion of Science KAKENHI JP19H04406 and the Visiting Researchers Program of Kyoto University Research Reactor Institute (R2013).
National Institute of Advanced Industrial Science and Technology has been studied terahertz (THz) coherent radiation in collaboration with Nihon University and Kyoto University. We have been developed a coherent transition radiation (CTR) source with macropulse power of 1 mJ using a screen monitor in the parametric X-ray line at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University. However, to obtain a THz-wave source with higher intensity, we have undertaken a development of a new THz-wave source based on coherent Cherenkov radiation (CCR) matched to circle plane wave. Bypassing an electron beam through a hollow conical dielectric having an apex angle equal to the Cherenkov angle, the wavefront of the CCR generated on the inner surface of the hollow conical dielectric matches on the basal plane. Therefore, it is possible to obtain a high-power beam that is easy to transport. We have already produced a hollow conical dielectric made of high-resistivity silicon and considered a position controller for the hollow conical dielectric. In this presentation, the status of the new THz-wave source will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB071

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paper received ※ 18 May 2021 paper accepted ※ 22 June 2021 issue date ※ 21 August 2021

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WEPAB072

PAX: A Plasma-Driven Attosecond X-Ray Source

plasma, electron, FEL, simulation

2755

C. Emma, J. Cryan, M.J. Hogan, K. Larsen, J.P. MacArthur, A. Marinelli, G.R. White, X.L. Xu
SLAC, Menlo Park, California, USA
A.C. Fisher, R.M. Hessami, P. Musumeci
UCLA, Los Angeles, California, USA
R. Robles
Stanford University, Stanford, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. This work was also partially supported by DOE grant DESC0009914
Plasma accelerators can generate ultra high brightness electron beams which open the door to light sources with smaller physical footprint and properties unachievable with conventional accelerator technology. In this work * we show that electron beams from Plasma WakeField Accelerators (PWFAs) can generate coherent tunable soft X-ray pulses with TW peak power and duration of tens of attoseconds in a meter-length undulator. These X-ray pulses are an order of magnitude more powerful, shorter and can be produced with better stability than state-of-the-art X-ray Free Electron Lasers (XFELs). The X-ray emission in this approach is driven by coherent radiation from a pre-bunched, near Mega Ampere (MA) current electron beam of attosecond duration rather than the SASE FEL process starting from noise. This approach significantly relaxes the restrictive requirements on emittance, energy spread, and pointing stability which has thus far hindered the realization of a high-gain FEL driven by a plasma accelerator. We discuss the approach and progress towards the experimental realization of this concept at the FACET-II accelerator facility.
* C. Emma, X. Xu, A. Fisher, J. P. MacArthur, J. Cryan, M. J. Hogan, P. Musumeci, G. White, A. Marinelli, "Terawatt attosecond X-ray source driven by a plasma accelerator", arXiv:2011.07163 (2020)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB072

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 31 August 2021

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WEPAB080

Near Threshold Pion Photoproduction on Deuterons

photon, multipole, polarization, scattering

2775

V. Shastri, V. Aswathi, S.P. Shilpashree
Christ University, School of Engineering and Technology, Bangalore, India

The study of photoproduction of mesons is a prime tool in understanding the properties of strong interactions. The only photoproduction reaction on deuteron with two-body final state is coherent pion photoproduction reaction. Several theoretical studies are being carried out on the pion photoproduction on deuterons since several decades. On the experimental side, the accelerator and detector technology has improved the developments. In the recent years, measurements of tensor analyzing powers associated with coherent and incoherent pion photoproduction are also being carried out at the VEPP-3 electron storage ring. In one of the recent measurements, Rachek et al"*" have observed discrepancy between theory and experiment at higher photon energies and have suggested for improvement of the theoretical models. In a more recent analysis,"**" the role of D-wave component on spin asymmetries have been identified. In view of these developments, the purpose of the present contribution is to study coherent pion photoproduction on deuterons using model independent irreducible tensor formalism developed earlier to study the photodisintegration of deuterons."***"
*I A Rachek et al., Few-Body Syst., 58, 29 (2017)
**H M Al Ghamdi et al, Brazillian Journal of Physics, 50, 615 (2020)
*** G Ramachandran, S P Shilpashree Phys. Rev. C 74, 052801(R) (2006)

Poster WEPAB080 [0.203 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB080

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paper received ※ 29 May 2021 paper accepted ※ 01 July 2021 issue date ※ 16 August 2021

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WEPAB097

Initial Nanoblade-Enhanced Laser-Induced Cathode Emission Measurements

electron, laser, cathode, simulation

2814

G.E. Lawler, J.I. Mann, J.B. Rosenzweig, V.S. Yu
UCLA, Los Angeles, California, USA
R.J. Roussel
University of Chicago, Chicago, Illinois, USA

Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132 and DOE HEP Grant DE-SC0009914
Nanostructured photocathodes offer a unique functionality not possible in traditional photocathodes, increasing beam brightness by reducing the effective emission area. Inspired by field emitter tips, we examine a possible extension for higher current operation, an extended nanoblade capable of producing asymmetric emittance electron beams. A full understanding of emission is necessary to establish the effectiveness of nanoblades as usable cathode for electron accelerators. Utilizing wet etching of silicon wafers, we arrive at a robust sample capable of dissipating incident laser fields in excess of 20 GV/m without permanent damage. Initial predictions and experiments from the nanotip case predict energies up to the keV scale from electron rescattering and fine features on the order of the photon quantum. We will present initial electron data from 800 nm Ti:S laser illumination and measurements of a focused 1 keV beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB097

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 15 August 2021

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WEPAB099

Near-Threshold Nonlinear Photoemission From Cu(100)

electron, laser, cathode, photon

2822

C.J. Knill, S.S. Karkare
Arizona State University, Tempe, USA
H.A. Padmore
LBNL, Berkeley, California, USA

Funding: National Science Foundation Grant No. PHY-1549132
Photocathodes that have a low mean transverse energy (MTE) are crucial to the development of compact X-ray Free Electron Lasers (XFEL) and ultrafast electron diffraction (UED) experiments. For FELs, low MTE cathodes result in a lower requirement for electron energy when lasing at a defined energy, and for a defined electron energy result in lasing at higher energy. For UED experiments, low MTE cathodes give a longer coherence length, allowing measurements on larger unit cell materials. A record low MTE of 5 meV has been recently demonstrated from a Cu (100) surface when measured near the photoemission threshold and cooled down to 30 K with liquid Helium [*]. For UED and XFEL applications that require a high charge density, the low quantum efficiency of Cu (100) near threshold necessitates the use of a high laser fluence to achieve the desired charge density [**]. At high laser fluences the MTE is limited by nonlinear effects, and therefore it is necessary to investigate near photoemission threshold at these high laser fluences. In this paper we report on nonlinear, near-threshold photoemission from a Cu (100) cathode, and its effect on the MTE.
* S. Karkare et al, Phys. Rev. Lett. 125, 054801 (2020)
** J. Bae et al, J. Appl. Phys., 124, 244903 (2018)

Poster WEPAB099 [0.829 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB099

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 29 August 2021

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WEPAB100

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

cathode, electron, laser, operation

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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WEPAB101

An Improved Model for Photoemission of Space Charge Dominated Picosecond Electron Bunches: Theory and Experiment

cathode, electron, laser, space-charge

2829

S.M. Polozov, V.I. Rashchikov
MEPhI, Moscow, Russia
M. Krasilnikov
DESY Zeuthen, Zeuthen, Germany

The emission of a short highly charged electron bunch in a radiofrequency photogun is discussed. The traditional space charge limited emission numerical model is extended by an introduction of positively charged ions arising in the cathode region and dynamically changing during the emission. Estimates on the time characteristics of the charge migrating process in the semiconductor region are given. The numerical results are compared with the results of other numerical models and with experimental observations at the Photo Injector Test facility at DESY in Zeuthen (PITZ).

Poster WEPAB101 [1.601 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB101

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paper received ※ 08 May 2021 paper accepted ※ 07 June 2021 issue date ※ 19 August 2021

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WEPAB106

Study on Durability Improvement of Cs-Te Photocathode by Means of Alkali Halide Protective Films

cathode, electron, ECR, laser

2847

K. Ezawa, R. Fukuoka, Y. Koshiba, T. Tamba, M. Washio
Waseda University, Tokyo, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

We have been conducting basic and applied research for generating high quality electron beams, using 1.6 cell laser photocathode RF-gun. In our laboratory, Cesium Telluride (Cs-Te), one of the semiconductor photocathodes, is used as an electron source for accelerator experiments. This semiconductor photocathode is known for high quantum efficiency (Q.E.) about 5~10% and 3-month 1/e lifetime. High Q.E. photocathodes can reduce the power requirement of the laser system, and long lifetime photocathodes can decrease the maintenance frequency, contributing to an efficient experimental environment. For these reasons, high Q.E. and long lifetime photocathodes are necessary in accelerator experiments. In order to produce robust photocathodes and extend the lifetime, we have conducted covering Cs-Te photocathodes with CsBr and CsI protective films. In this conference, we report the thickness dependency on the lifetime of Cs-Te photocathodes when we intentionally exposed oxygen gas to coated and non-coated Cs-Te photocathodes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB106

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 15 August 2021

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WEPAB109

Initial Study of GaN Thin Films for Photocathodes Prepared by Magnetron Sputtering on Copper Substrates

cathode, electron, plasma, gun

2850

M. Vogel, X. Jiang, C. Wang
University Siegen, Siegen, Germany
P. Murcek, J. Schaber, R. Xiang
HZDR, Dresden, Germany

Funding: This research is funded by the Federal Ministry of Education and Research of Germany in the framework of BETH (project number 05K19PSB).
On the path for high brightness electron beams, Gallium Nitride (GaN) is one promising candidate for a photo-cathode material. In this contribution, we report on the continuation of the study to optimize the crystallization quality and crystallography of Mg-doped GaN samples on copper substrates that are synthesized by RF magnetron sputtering. SEM and XRD results show that the pretreatment methods and the sputtering conditions (temperature, sputtering power, and partial pressure of the reactive gas) can both affect the morphology and crystal quality of GaN films. The initial QE measurements of these samples are done in our newly build in-situ QE measurement system and the first results of QE analyses done at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) are presented in a dedicated contribution.
Part of this work was performed at the Micro- and Nanoanalytics Facility (MNaF) of the University of Siegen.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB109

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

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WEPAB111

Controlled Degradation by Oxygen Exposure in the Performance of a Ag (100) Single-Crystal Photocathode

cathode, electron, cryogenics, emittance

2856

L.A.J. Soomary, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The search for high-performance photocathode electron sources is a priority in the accelerator science community. The surface characteristics of a photocathode define many important factors of the photoemission including the work function, intrinsic emittance, and quantum efficiency of the photocathode. These factors in turn define the electron beam performance which is measurable as normalized emittance, brightness, and energy spread*. Strategies for improving these parameters vary, but understanding and influencing the relevant cathode surface physics which underpin these attributes is a primary focus for the electron source community**. As such, pure metal photocathodes and their performance at UV wavelengths are of interest as seen at the LCLS at SLAC and CLARA at Daresbury. We present performance data for an Ag (100) single-crystal photocathode under illumination at 266 nm wavelength, with known levels of surface roughness, using our Transverse Energy Spread Spectrometer (TESS)*** both at room and cryogenic temperatures. Crucially our data shows the effect of progressive degradation in the photo-cathode performance as a consequence of exposure to controlled levels of oxygen.
* D.H. Dowell, et al., Nucl. Instr. and Meth. A (2010), doi:10.1016/j.nima.2010.03.104
** Appl. Phys. Lett. 89, 224103 (2006); doi:10.1063/1.2387968
*** Proc. FEL’13, TUPPS033, 290-293

Poster WEPAB111 [0.866 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB111

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paper received ※ 20 May 2021 paper accepted ※ 22 June 2021 issue date ※ 31 August 2021

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WEPAB112

Performance Characterisation of a Cu (100) Single-Crystal Photocathode

cathode, electron, emittance, photon

2860

L.A.J. Soomary, D.P. Juarez-Lopez, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The search for high performance photocathode electron sources is a priority in the accelerator science community. The surface characteristics of a photocathode define important factors of the photoemission including the intrinsic emittance, the quantum efficiency and the work function of the photocathode. These factors in turn define the electron beam performance which are measurable as emittance, brightness and energy spread. We have used ASTeC’s Multiprobe (SAPI)* to characterise and analyse photocathode performance using multiple techniques including XPS, STM, and LEED imaging, and their Transverse Energy Spread Spectrometer (TESS)** to measure mean transverse energy (MTE). We present characterisation measurements for a Cu (100) single-crystal photocathode sample with data from SAPI confirming the crystallographic face and showing surface composition and roughness, supported by data from TESS showing the photocathode electron beam energy spread.
* B.L. Militsyn, 4-th EuCARD2 WP12.5 meeting, Warsaw, 14-15 March 2017
**Proc. FEL’13, TUPPS033, 290-293

Poster WEPAB112 [0.814 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB112

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 22 August 2021

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WEPAB135

Progress of the Development of a Superconducting Undulator as a THz Source for FELs

undulator, radiation, FEL, electron

2933

J. Gethmann, S. Casalbuoni, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
KIT, Karlsruhe, Germany
D. Astapovych, H. De Gersem, E. Gjonaj
TEMF, TU Darmstadt, Darmstadt, Germany
S. Casalbuoni
EuXFEL, Schenefeld, Germany

Funding: This work is supported by the BMBF project 05K19VK2 SCUXFEL (Federal Ministry of Education and Research) and by the DFG-funded Doctoral School KSETA: Science and Technology.
To produce radiation in the THz frequency range at X-ray Free Electron Lasers, undulators with large period length, high fields, and large gaps are required. These demands can be fulfilled by superconducting undulators. In this contribution, the actual requirements on the main parameters of such a superconducting undulator will be discussed and the progress of the design will be discussed. In addition, beam impedance and heat load results obtained analytically as well as by large-scale wakefield simulations will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB135

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

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WEPAB151

Regenerative Beam Break Up Instability Analysis

cavity, HOM, dipole, linac

2971

V. Volkov, V.M. Petrov
BINP SB RAS, Novosibirsk, Russia

New features of regenerative beam break up (BBU) instability such as the typing of high order dipole modes (HOMs)in each cavity by two classes, one of them are stable and other ones are unstable, HOM effective quality factor depending on average beam current, and normalized invariable threshold current individually characterizes each HOM are investigated in this article in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB151

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 01 September 2021

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WEPAB152

Carbon Nanotubes as Cold Electron Field Emitters for Electron Cooling in the CERN Extra Low Energy Antiproton (ELENA) Ring

electron, vacuum, proton, antiproton

2975

B. Galante, G. Tranquille
CERN, Meyrin, Switzerland
O. Apsimon, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
IFIC, Valencia, Spain

In ELENA electron cooling reduces the emittance of the antiproton beam allowing to deliver a high-quality beam to the experiments at the unprecedented low energy of 100 keV. To cool the antiproton beam at this low energy, the electron gun must emit electrons with as monoenergetic a distribution as possible. The currently used thermionic gun limits the cooling performance due to the relatively high transverse energy spread of the emitted electrons. Optimization is therefore being studied, aiming at developing a cold-cathode electron gun. This has led to the investigation of carbon nanotubes (CNTs) as cold electron field emitters. CNTs are considered the most promising field emitter material due to their high aspect ratio, chemical stability, and capability to deliver high current densities. To assess the feasibility of using such material operationally a full characterization is required, focussing on key parameters such as emitted current, emission stability, and lifetime. This contribution will present the status of ongoing experiments reporting on the conditioning process necessary to reach good stability over time and the emitting performance of different CNT arrays.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB152

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

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WEPAB163

An X-Band Ultra-High Gradient Photoinjector

gun, emittance, linac, solenoid

2986

S.V. Kuzikov, S.P. Antipov, P.V. Avrakhov, E. Dosov, C.-J. Jing, E.W. Knight
Euclid TechLabs, Solon, Ohio, USA
G. Ha, C.-J. Jing, W. Liu, P. Piot, J.G. Power, D.S. Scott, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid Beamlabs, Bolingbrook, USA
X. Lu
MIT/PSFC, Cambridge, Massachusetts, USA
X. Lu
SLAC, Menlo Park, California, USA
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot, W.H. Tan
Northern Illinois University, DeKalb, Illinois, USA
E.E. Wisniewski
IIT, Chicago, Illinois, USA

Funding: This work was supported by DoE SBIR grant # DE-SC0018709.
High brightness beams appealing for XFELs and UEM essentially imply a high current and a low emittance. To obtain such beams we propose to raise the accelerating voltage in the gun mitigating repealing Coulomb forces. An ultra-high gradient is achieved utilizing a short-pulse technology. We have designed a room temperature X-band 1,5 cell gun that is able to inject 4 MeV, 100 pC bunches with as low as 0.15 mcm normalized transverse emittance. The gun is operated with as high gradients as 400 MV/m and fed by 200 MW, 10 ns RF pulses generated with Argonne Wakefield Accelerator (AWA) power extractor. We report results of low RF power tests, laser alignment test results, and successful gun conditioning results carried out at nominal RF power.

Poster WEPAB163 [5.427 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB163

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

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WEPAB164

Electrodeless Diamond Beam Halo Monitor

electron, coupling, radiation, vacuum

2990

S.V. Kuzikov, S.P. Antipov, P.V. Avrakhov, E. Dosov, E.W. Knight, Y. Zhao
Euclid TechLabs, Solon, Ohio, USA
J.G. Power, J. Shao
ANL, Lemont, Illinois, USA

Funding: This work was supported by DoE SBIR grant # DE-SC0019642.
Beam halo measurement is important for novel x-ray free-electron lasers which have remarkably high repetition rate and average power. We propose diamond as a radiation hard material that can be used to measure the flux of passing particles based on a particle-induced conductivity effect. Our diamond electrodeless monitor is based on a microwave measurement of the change in the resonator coupling and eigenfrequency. For measurements, we put a sensitive diamond sample in a resonator that intercepts the halo. By measuring the change in RF properties of the resonator, one can infer the beam halo parameters scanning across the beam to map its transverse distribution. In recent experiments we used a Vertical Beam Test Stand (VBS), delivered DC electron beam of the 20-200 keV energy with the current up to 50 µA, to characterize several diamond samples. We have designed and fabricated a scanning diamond monitor, based on an X-band resonator, which was tested at Argonne Wakefield Accelerator (AWA) with a multi-MeV electron beam.

Poster WEPAB164 [5.138 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB164

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paper received ※ 14 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021

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WEPAB172

Recent Developments of the IDEAS-Halo Detector

detector, electron, vacuum, FEL

3005

A. Liu, J.R. Callahan, B.T. Freemire
Euclid TechLabs, Solon, Ohio, USA
J.F. Power, J.H. Shao
ANL, Lemont, Illinois, USA

Funding: This work was performed at Euclid and Argonne National Laboratory, and was supported by the US DOE Office of Science under contract number DE-SC0019538.
Euclid Techlabs has been designing and testing a cost-effective iris diaphragm beam halo/profile detector, which can be easily configured to work with various primary beam energies and sites. Besides working as a measurement device, it can also work as a controllable beam scraper/collimator. This novel iris diaphragm detector utilizes the current signal produced by the beam charge deposition on the moveable conductive iris blades, to accurately measure the beam distribution from the outlier to the beam core. In this paper, we discuss the recent developments of our iris diaphragm e-beam apparatus series (IDEAS)-halo detector, including its geometry upgrades and newest beam experiments done at the AWA cathode testbed (ACT) of Argonne National Laboratory.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB172

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paper received ※ 03 June 2021 paper accepted ※ 22 July 2021 issue date ※ 27 August 2021

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WEPAB178

Non-Adiabatic Longitudinal Bunch Manipulation at Flattop of the J-PARC MR

bunching, extraction, kicker, flattop

3023

F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

The J-PARC MR delivers the high-intensity proton beams for the neutrino experiment. Eight bunches of high peak current are extracted by the extraction kickers, therefore the neutrino beam has a similar time structure. The new Intermediate Water Cherenkov Detector (IWCD) will be constructed for the future neutrino experiment and a low peak time structure is desired by the IWCD. Thus, we consider bunch manipulation at flattop of the MR for reducing the peak current. The manipulation requires a longer repetition period to extend the flattop. This reduces the output beam power. The manipulation should be quickly done to minimize the loss of the beam power. Also, the beam gap must be kept for the rise time of the extraction kicker. We propose a non-adiabatic bunch manipulation using the multiharmonic rf voltage. By using the neighbor harmonic of the accelerating harmonic, the first and eighth bunches can be decelerated and accelerated, respectively. After a certain period, the rf phase is flipped to pi for debunching. Thanks to the initial deceleration and acceleration, the beam gap for the kickers is kept. We present the concept and the longitudinal simulation result.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB178

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paper received ※ 17 May 2021 paper accepted ※ 25 June 2021 issue date ※ 28 August 2021

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WEPAB181

New Opportunities in Low Energy Antiproton Research

electron, proton, antiproton, FEL

3035

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 721559.
Experiments with low-energy antiprotons are at the cutting edge of science and offer unique opportunities to test some of the fundamental laws of physics. The experiments are, however, very difficult to realize. They critically depend on high-performance numerical tools that can model realistic beam transport and storage and also require advanced beam monitors and detectors that can fully characterize the beam. Finally, novel experiments need to be designed that exploit the enhanced beam quality that the new ELENA ring at CERN provides. This paper presents some selected findings from the pan-European AVA network’s three scientific work packages. It shows results from studies into electron cooling at the new ELENA storage ring, research into carbon nanotubes as cold electron field emitters for electron cooling, and how antiproton-atom collision experiments can be optimized using GEANT4. Finally, the paper gives an overview of the network’s interdisciplinary training program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB181

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

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WEPAB183

Big Data Techniques for Accelerator Optimization

plasma, laser, wakefield, radiation

3039

C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from STFC under grant reference ST/P006752/1.
Accelerators and the experiments that they enable are some of the largest, most data-intensive, and most complex scientific systems in existence. The interrelations between machine subsystems are complicated and often nonlinear. The system dynamics involve large parameter spaces that evolve over multiple relevant time scales and accelerator systems. Any accelerator-based experiments and applications are almost always difficult to model. LIV. DAT, the Liverpool Centre for Doctoral Training in Data-intensive science, was established in 2017 as a hub for training students in Big Data science. The centre currently has 36 PhD students that are working across nuclear, particle and astrophysics, as well as in accelerator science. This paper presents results from R&D into betatron radiation models and beam parameter reconstruction for plasma acceleration experiments at FACET-II, simulations for MeV energy gain in dielectric structures driven by a CO₂ laser, and modelling of seeded self-modulation of long elliptical bunches in plasma. It also gives an overview of the training program offered to the LIV. DAT students.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB183

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

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WEPAB185

Target Bypass Beam Optics for Future High Intensity Fixed Target Experiments in the CERN North Area

target, proton, quadrupole, optics

3046

G.L. D’Alessandro, D. Banerjee, J. Bernhard, M. Brugger, N. Doble, L. Gatignon, A. Gerbershagen, B. Rae, F.M. Velotti
CERN, Meyrin, Switzerland
S.M. Gibson
JAI, Egham, Surrey, United Kingdom

Several of the proposed experiments for operation at the K12 beam line would profit from significant beam intensity increase. Among those, there is the KLEVER experiment that would require an intensity of 2x10¹³ protons per 4.8 s long spill. The main goal of the experiment is to measure BR(KL->pi0 nu nu) to test the Standard Model structure by itself, and in combination with results from NA62 for BR(K±>pi+ nu nu). NA62 could also profit from higher intensities, and could be run in a new configuration called NA62HI(gher intensity). In the current configuration the beam is transported from the SPS to the TT24 beamline. This beamline leads to the T4 target that attenuates the beam for P42. After T4 the beam is directed into the P42 beamline before impinging on the T10 target and creating the particles necessary for the experiment. Those are finally transported to the detector via K12. This paper presents the idea of partially bypassing T4 and changing the P42 beamline configuration in order to have a sufficiently small beam size at the T10 target for both KLEVER and NA62-HI. Optics studies are developed in MADX and the AppLE.py, software developed at CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB185

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paper received ※ 17 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021

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WEPAB186

Studies for the K12 High-Intensity Kaon Beam at CERN

detector, simulation, target, kaon

3049

G.L. D’Alessandro, D. Banerjee, J. Bernhard, M. Brugger, N. Doble, L. Gatignon, A. Gerbershagen, R. Marchevski, B. Rae, S. Schuchmann, F.W. Stummer, M.W.U. Van Dijk
CERN, Meyrin, Switzerland
S.T. Boogert, S.M. Gibson, L.J. Nevay
JAI, Egham, Surrey, United Kingdom

The NA62 experiment is a fixed target experiment located in the North Area of CERN and has as main goal the measurement of the branching ratio of the rare decay K±>pi+vv. The primary proton beam from the SPS accelerator interacts with the T10 beryllium target and the generated 75 GeV/c secondary particles, containing about 6% of positive kaons, are transported by the K12 beamline to the NA62 experiment. Studies in this paper present detailed simulations of the K12 beamline developed in both FLUKA and BDSIM codes, which reproduce the current configuration of K12 for the NA62 experiment. The beam optics parameters of K12 are studied in BDSIM and compared to MADX optics and tracking calculations. The models in FLUKA and BDSIM are used for beam studies and muon production at various locations along the beamline, and the parameters obtained from simulations are benchmarked against data recorded by the experiment. The impact of the Cherenkov kaon tagging detector (CEDAR) on the beam quality is calculated for two different gas compositions in view of a possible upgrade of the detector.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB186

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paper received ※ 17 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021

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WEPAB187

The ENUBET Multi Momentum Secondary Beamline Design

target, kaon, electron, proton

3053

E.G. Parozzi, N. Charitonidis
CERN, Geneva, Switzerland
G. Brunetti, E.G. Parozzi, F. Terranova
Universita Milano Bicocca, MILANO, Italy
A. Longhin, M. Pari, F. Pupilli
INFN- Sez. di Padova, Padova, Italy
A. Longhin, M. Pari
Univ. degli Studi di Padova, Padova, Italy
E.G. Parozzi, F. Terranova
INFN MIB, MILANO, Italy

The aim of neutrino physics for the next decades is to detect effects due to CP violation, mass hierarchy, and search for effects beyond the Standard Model predictions. Future experiments need precise measurements of the neutrino interaction cross-sections at the ~GeV/c regime, currently limited by the exact knowledge of the initial neutrino flux on a ~10-20% uncertainty level. The ENUBET project is proposing a novel facility, capable of constraining the neutrino flux normalization through the precise monitoring of the Ke3 (K±>e+pi0nu) decay products in an instrumented decay tunnel. ENUBET can also monitor muons from the two body kaon and pion decays (nu flux) and measure the neutrino energy with a 10% precision without relying on the event reconstruction at the neutrino detector. We present here a novel design based on a broad (4-8.5 GeV/c) momentum range secondary beamline, that widen the cross-section energy range that can be explored by ENUBET. In this poster, we discuss the target optimization studies and we show the early results on the new line’s optics and the layout design. We discuss the expected performance of this line and the forthcoming activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB187

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paper received ※ 13 May 2021 paper accepted ※ 29 July 2021 issue date ※ 14 August 2021

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WEPAB188

New Method to Search for Axion-Like Particles Demonstrated with Polarized Beam at the COSY Storage Ring

polarization, resonance, storage-ring, dipole

3057

S. Karanth
Jagiellonian University, Kraków, Poland

The axion was originally proposed to explain the small size of CP violation in quantum chromodynamics. It might be a candidate for dark matter in the universe. Axions or axion-like particles (ALPs) when coupled to gluons induce an oscillating Electric Dipole Moment (EDM) along the nucleon’s spin direction. At the Cooler Synchrotron (COSY) in Jülich, this principle was used to perform a first test experiment to search for ALPs using an in-plane polarized deuteron beam. If the spin precession frequency equals the EDM oscillation frequency, a resonance occurs that accumulates the rotation of the polarization out of the ring plane. Since the axion frequency is unknown, the beam momentum was ramped to search for a vertical polarization jump that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the EDM oscillations. We scanned a frequency window of about a 1-kHz width around the spin precession frequency of 121 kHz. This talk will describe the experiment and show preliminary results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB188

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

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WEPAB205

XiPAF Synchrotron Slow Extraction Commissioning

extraction, synchrotron, proton, sextupole

3106

W.B. Ye, X. Guan, Y. Li, X.Y. Liu, M.W. Wang, X.W. Wang, Y. Yang, H.J. Yao, H.J. Zeng, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, M.C. Wang, Z.M. Wang, Y. Yang, M.T. Zhao
NINT, Shannxi, People’s Republic of China

Xi’an 200 MeV Proton Application Facility (XiPAF) is a project to fulfill the need for the experimental simulation of the space radiation environment. It comprises a 7 MeV H⁻ linac, a 60~230 MeV proton synchrotron, and experimental stations. Slow extraction commissioning for 60 MeV proton beam in XiPAF synchrotron has been finished. After commissioning, the maximal experiment extraction efficiency with the RF-knockout (RF-KO) method can up to 85%. The reason for beam loss has been analyzed and presented in this paper. Besides, an experiment of multiple energy extraction has been conducted in XiPAF synchrotron. The proton beams of 3 different energies were successfully extracted in 1.54 s.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB205

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paper received ※ 18 May 2021 paper accepted ※ 07 July 2021 issue date ※ 31 August 2021

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WEPAB213

Optimization of Antiproton-Atom Collision Studies Using GEANT4

proton, antiproton, simulation, bunching

3126

V. Rodin, A. Farricker, N. Kumar, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, V. Rodin, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
The interaction between antiprotons and hydrogen or helium atoms is a fundamental problem in many-particle atomic physics, attracting strong interest from both theory and experiments. Atomic collisions are ideal to study the three and four-body Coulomb problem as the number of possible reaction channels is limited. Currently, only the total cross-sections of such interactions have been measured in an energy range between keV and a few MeV. This contribution investigates the discrepancies between different theories and available experimental data. It also describes a pathway for obtaining differential cross-sections. A purpose-designed experimental setup is presented and detailed Geant4 simulations provide an insight into the interaction between short (ns) antiproton bunches and a dense gas-jet target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB213

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paper received ※ 23 May 2021 paper accepted ※ 30 June 2021 issue date ※ 24 August 2021

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WEPAB214

Realistic Simulations of Stray Field Impact on Low Energy Transfer Lines

solenoid, simulation, proton, antiproton

3130

V. Rodin, S. Padden, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Farricker, S. Padden, V. Rodin, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
UVEG, Burjasot (Valencia), Spain

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
Low energy (~100 keV) facilities working with antiprotons, heavy ions, or charged molecules may experience severe beam transport instabilities caused by field imperfections. For example, long (~10 m), unshielded beamlines will not be able to transfer particles due to the natural Earth magnetic field or stray fields from closely located experiments. Currently, only a limited number of simulation codes allow a simplified representation of such field errors, limiting capabilities for beam delivery optimization. In this contribution, a new simulation approach is presented that can provide detailed insight into 4D beam transport. It illustrates the impact of imperfections and stray fields on beam stability and quality through simulations of two antiproton experiments located in the Antimatter Factory (AD) at CERN in Geneva, Switzerland. Magnetic field imperfections are examined in two different ways, providing greater flexibility and an opportunity to benchmark all outcomes. Simulation performance is analyzed as a function of the level of detail and efficiency.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB214

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

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WEPAB233

Excitation of Micro-Bunching in Short Electron Bunches Using RF Amplitude Modulation

bunching, synchrotron, electron, radiation

3173

T. Boltz, E. Blomley, M. Brosi, E. Bründermann, B. Härer, A. Mochihashi, A.-S. Müller, P. Schreiber, M. Schuh, M. Yan
KIT, Karlsruhe, Germany

In its short-bunch operation mode, the KIT storage ring KARA provides picosecond-long electron bunches, which emit coherent synchrotron radiation (CSR) up to the terahertz frequency range. Due to the high spatial compression under these conditions, the self-interaction of the bunch with its own emitted CSR induces a wake-field, which significantly influences the longitudinal charge distribution. Above a given threshold current, this leads to the formation of dynamically evolving micro-structures within the bunch and is thus called micro-bunching instability. As CSR is emitted at wavelengths corresponding to the spatial dimension of the emitter, these small structures lead to an increased emission of CSR at higher frequencies. The instability is therefore deliberately induced at KARA to provide intense THz radiation to dedicated experiments. To further increase the emitted power in the desired frequency range, we consider the potential of RF amplitude modulations to intentionally excite this form of micro-bunching in short electron bunches. This work is supported by the BMBF project 05K19VKC TiMo (Federal Ministry of Education and Research).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB233

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

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WEPAB257

Matching of a Space-Charge Dominated Beam into the Undulator of the THz SASE FEL at PITZ

undulator, electron, quadrupole, FEL

3244

X. Li, Z. Aboulbanine, G.D. Adhikari, N. Aftab, Z.G. Amirkhanyan, P. Boonpornprasert, M.E. Castro Carballo, N. Chaisueb, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, O. Lishilin, A. Lueangaramwong, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany

The Photo Injector Test facility at DESY in Zeuthen (PITZ) is developing a THz SASE FEL as a prototype high repetition rate accelerator-based source for the THz-pumped, X-ray-probed experiments at the European XFEL. For the generation of THz pulses of mJ-level energy from SASE, an electron beam with a high charge (up to 4 nC) and high peak current (~200 A) will be injected into an LCLS-I undulator, which is currently being installed at the end of the photo-injector. The narrow vacuum chamber (11x5 mm) between the magnetic poles and the strong vertical focusing from the undulator, as well as the lack of beam diagnostics, have made it a challenge to match the space-charge dominated beam into the undulator without beam loss during the following transport. In this paper, boundary conditions of a matched electron beam will be discussed and the simulation and experimental study on our matching strategy will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB257

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paper received ※ 08 May 2021 paper accepted ※ 02 July 2021 issue date ※ 13 August 2021

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WEPAB266

Simulation Studies of Plasma Cascade Amplifier

electron, simulation, plasma, emittance

3265

J. Ma, V. Litvinenko, G. Wang
BNL, Upton, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Plasma cascade amplifier (PCA) is an advanced design of amplifier for the coherent electron cooling (CeC) experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Working principle of PCA is the new plasma cascadeμbunching instability occurring in electron beams propagating along a straight trajectory. PCA is cost-effective as it does not require separating electron and hadron beams. SPACE, a parallel, relativistic 3D electromagnetic Particle-in-Cell (PIC) code, has been used for simulation studies of PCA.

Poster WEPAB266 [2.317 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB266

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

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WEPAB270

Characterization and Simulation of Optical Delay System for the Proof-of-Principle Experiment of Optical Stochastic Cooling at IOTA

undulator, radiation, simulation, kicker

3269

A.J. Dick, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J.D. Jarvis
Fermilab, Batavia, Illinois, USA
P. Piot
ANL, Lemont, Illinois, USA

Funding: CBB NSF-PHY-1549132 DOE DE-SC0018656 DOE DE-AC02-07CH11359
The Optical Stochastic Cooling (OSC) experiment at Fermilab’s IOTA storage ring uses two undulators to cool the beam over many turns. The radiation emitted by electrons in the first undulator is delayed and imaged in the second undulator where it applies a corrective energy kick on the electrons. Imperfections in the manufacturing of the delay plates can lead to a source of error. This paper presents the experimental characterization of the absolute thickness of these delay plates using an interferometric technique. The measured "thickness maps" are implemented in the Synchrotron Radiation Workshop (SRW) program to assess their impact on the delayed radiation pulse.

Poster WEPAB270 [2.578 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB270

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paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

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WEPAB272

Field-Off Multiple Coulomb Scattering in the MICE Liquid Hydrogen Absorber

scattering, emittance, beam-cooling, radiation

3277

G.T. Chatzitheodoridis
USTRAT/SUPA, Glasgow, United Kingdom

It is anticipated that high brightness muon beams will be used primarily in two types of accelerators, a muon collider and a neutrino factory. The primary challenge posed by using muons as the working particle of an accelerator physics system, and the reason it has not been used extensively in modern particle physics experiments, is its short life-time (2.2μseconds at rest) and the relatively long cooling periods required by current cooling techniques. The Muon Ionization Cooling Experiment (MICE), is a multi-national accelerator physics initiative which has demonstrated Ionization Cooling (IC); a new, rapid beam-cooling technique suitable for the short-lived muon. The performance of IC depends on two key processes - energy loss due to collisional ionization, and Multiple Coulomb Scattering (MCS) - for which accurate models are crucial in parametrizing the method and enabling quantitative design of future muon accelerators. Experimental measurements of MCS of positive straight-track muons with momenta in the range 170-240 MeV/c in liquid H₂ are reported in this study.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB272

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

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WEPAB281

The Precision Laser Inclinometer

laser, luminosity, detector, operation

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.

DOI •

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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WEPAB285

High Resolution Arrival Time Measurement of the Seed Laser

laser, FEL, timing, electron

3320

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

The Shanghai soft X-ray Free-Electron Laser facility (SXFEL) is a fourth-generation linac-based light source, capable of producing X-ray pulses with a duration of tens of femtosecond. The seed laser for external seeding FEL, therefore, has tight requirements for relative arrival time to the electron bunch. To reach the required energy and wavelength for external seeding FEL, further optical amplification and frequency conversion is needed. These include reflection and propagation in different material and in air, in addition, also include the long laser transport beamline to the undulator, make the laser pulses arrival time influenced by environmental variation. To reach the required specification, high-resolution measurement of the laser arrival time is necessary. In this paper, we present a general concept for the measurement of the laser arrival time.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB285

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

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WEPAB289

Machine Learning Based Spatial Light Modulator Control for the Photoinjector Laser at FLUTE

laser, electron, network, target

3332

C. Xu, E. Bründermann, A.-S. Müller, M.J. Nasse, A. Santamaria Garcia, C. Sax, C. Widmann
KIT, Karlsruhe, Germany
A. Eichler
DESY, Hamburg, Germany

Funding: C. Xu acknowledges the support by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
FLUTE (Ferninfrarot Linac- und Test-Experiment) at KIT is a compact linac-based test facility for novel accelerator technology and a source of intense THz radiation. FLUTE is designed to provide a wide range of electron bunch charges from the pC- to nC-range, high electric fields up to 1.2 GV/m, and ultra-short THz pulses down to the fs-timescale. The electrons are generated at the RF photoinjector, where the electron gun is driven by a commercial titanium sapphire laser. In this kind of setup the electron beam properties are determined by the photoinjector, but more importantly by the characteristics of the laser pulses. Spatial light modulators can be used to transversely and longitudinally shape the laser pulse, offering a flexible way to shape the laser beam and subsequently the electron beam, influencing the produced THz pulses. However, nonlinear effects inherent to the laser manipulation (transportation, compression, third harmonic generation) can distort the original pulse. In this paper we propose to use machine learning methods to manipulate the laser and electron bunch, aiming to generate tailor-made THz pulses. The method is demonstrated experimentally in a test setup.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB289

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 26 August 2021

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WEPAB292

Application of Machine Learning to Predict the Response of the Liquid Mercury Target at the Spallation Neutron Source

target, neutron, simulation, proton

3340

L. Lin, S. Gorti, J.C. Mach, H. Tran, D.E. Winder
ORNL, Oak Ridge, Tennessee, USA

Funding: Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Avenue., SW Washington, DC 20585 P: (301) 903 - 3081 F: (301) 903 - 6594
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is currently the most powerful accelerator-driven neutron source in the world. The intense proton pulses strike on SNS’s mercury target to provide bright neutron beams, which also leads to severe fluid-structure interactions inside the target. Prediction of resultant loading on the target is difficult particularly when helium gas is intentionally injected into mercury to reduce the loading and mitigate the pitting damage on the target’s internal walls. Leveraging the power of machine learning and the measured target strain, we have developed machine learning surrogates for modeling the discrepancy between simulations and experimental strain data. We then employ these surrogates to guide the refinement of the high-fidelity mercury/helium mixture model to predict a better match of target strain response.

Poster WEPAB292 [0.930 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB292

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

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WEPAB294

LLRF Control and Synchronization System of the ARES Facility

LLRF, gun, laser, distributed

3347

S. Pfeiffer, J. Branlard, F. Burkart, M. Hoffmann, T. Lamb, F. Ludwig, H. Schlarb, S. Schulz, B. Szczepanski, M. Titberidze
DESY, Hamburg, Germany

The linear accelerator ARES (Accelerator Research Experiment at SINBAD) is a new research facility at DESY. Electron bunches with a maximum repetition rate of 50 Hz are accelerated up to 155 MeV. The facility aims for ultra-stable sub-femtosecond arrival-times and high peak-currents at the experiment, placing high demands on the reference distribution and field regulation of the S-band RF structures. In this paper, we report on the current status of the RF reference generation, facility-wide distribution, and the LLRF systems of the RF structures.

Poster WEPAB294 [2.394 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB294

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paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 20 August 2021

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WEPAB305

Teeport: Break the Wall Between the Optimization Algorithms and Problems

controls, real-time, monitoring, GUI

3387

Z. Zhang, X. Huang, M. Song
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.
Optimization algorithms/techniques such as genetic algorithm (GA), particle swarm optimization (PSO) and Gaussian process (GP) have been widely used in the accelerator field to tackle complex design/online optimization problems. However, connecting the algorithm with the optimization problem can be difficult, sometimes even unrealistic, since the algorithms and problems could be implemented in different languages, might require specific resources, or have physical constraints. We introduce an optimization platform named Teeport that is developed to address the above issue. This real-time communication (RTC) based platform is particularly designed to minimize the effort of integrating the algorithms and problems. Once integrated, the users are granted a rich feature set, such as monitoring, controlling, and benchmarking. Some real-life applications of the platform are also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB305

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 27 August 2021

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WEPAB306

Applying Machine Learning to Optimization of Cooling Rate at Low Energy RHIC Electron Cooler

electron, simulation, network, emittance

3391

Y. Gao, K.A. Brown, P.S. Dyer, S. Seletskiy, 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.
The Low Energy RHIC electron Cooler (LEReC) is a novel, state-of-the-art, electron accelerator for cooling RHIC ion beams, which was recently built and commissioned. Optimization of cooling with LEReC requires fine-tuning of numerous LEReC parameters. In this work, initial optimization results of using Machine Learning (ML) methods - Bayesian Optimization (BO) and Q-learning are presented. Specially, we focus on exploring the influence of the electron trajectory on the cooling rate. In the first part, simulations are conducted by utilizing a LEReC simulator. The results show that both methods have the capability of deriving electron positions that can optimize the cooling rate. Moreover, BO takes fewer samples to converge than the Q-learning method. In the second part, Bayesian optimization is further trained on the historical cooling data. In the new samples generated by the BO, the percentage of larger cooling rates data is greatly enhanced compared with the original historical data.

Poster WEPAB306 [1.083 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB306

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paper received ※ 12 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021

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WEPAB309

Study and Design of the Appropriate High-Performance Computing System for Beamline Data Analysis Application at Iranian Light Source Facility (ILSF)

software, hardware, data-analysis, network

3399

A. Khaleghi, M. Akbari
ILSF, Tehran, Iran
H. Haedar, K. Mahmoudi, M. Takhttavani
IKIU, Qazvin, Iran
S. Mahmoudi
Sharif University of Technology (SUT), Tehran, Iran

Data analysis is a very important step in doing experiments at light sources, where multiple application and software packages are used for this purpose. In this paper we have reviewed some software packages that are used for data analysis and design at Iranian Light Source Facility then according to their processing needs, after taking in mind different HPC scenarios a suitable architecture for deployment of the ILSF HPC is presented. The proposed architecture is a cluster of 64 computing nodes connected through Ethernet and InfiniBand network running a Linux operating system with support of MPI parallel environment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB309

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 01 September 2021

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WEPAB315

360 Degree Panoramic Photographs During the Long Shutdown 2 of the CERN Machines and Facilities

database, site, interface, HOM

3410

T.W. Birtwistle, A. Ansel, S. Bartolomé Jiménez, B. Feral, G. Lacerda, A.-L. Perrot, J.F. Piñera Ovejero
CERN, Geneva, Switzerland

Studies and preparation of activities are key to the success of short technical stops and longer shutdowns in CERN’s accelerator complex. The ’Panorama’ tool offers a virtual tour of our facilities, and thanks to integration with other CERN tools, further complementary information can be easily retrieved, including layout information, equipment detail, and a history of changes. The tool was used to support the preparation and the execution of works during the Long Shutdown 2. It helped to optimize machine (accelerator/decelerator) interventions and hence reduce potential radiation exposure, as well as to ease integration studies. Thanks to its user-friendliness, the tool is now also used for educational and outreach activities. The current instantiation of the ’Panorama’ tool and related processes is presented, alongside the benefits that the tool can bring to the accelerator complex community. A particular focus is on the Long Shutdown 2. Future planned developments and improvements are also described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB315

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paper received ※ 11 May 2021 paper accepted ※ 14 June 2021 issue date ※ 21 August 2021

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WEPAB331

Application of KALYPSO as a Diagnostic Tool for Beam and Spectral Analysis

electron, detector, laser, synchrotron

3451

M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’
KALYPSO is a novel detector capable of operating at frame rates up to 12 MHz developed and tested at the institute of data processing and electronics (IPE) and employed at Karlsruhe Research Accelerator (KARA) which is part of the Test Facility and Synchrotron Radiation Source KIT. This detector consists of silicon, InGaAs, PbS, or PbSe line array sensor with spectral sensitivity from 350 nm to 5000 nm. The unprecedented frame rate of this detector is achieved by a custom-designed ASIC readout chip. The FPGA-readout architecture enables continuous data acquisition and real-time data processing. Such a detector has various applications in the fields of beam diagnostics and spectral analysis. KALYPSO is currently employed at various synchrotron facilities for electro-optical spectral decoding (EOSD) to study the longitudinal profile of the electron beam, to study the energy spread of the electron beam, tuning of free-electron lasers (FELs), and also in characterizing laser spectra. This contribution will present an overview of the results from the mentioned applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB331

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

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WEPAB337

Some Methods of Making Titanium Vacuum Chamber Act as Getter Pump for UHV/XHV

vacuum, ECR, electron, hadron

3471

J. Kamiya, T. Takano, H. Yuza
JAEA/J-PARC, Tokai-mura, Japan
K. Wada
Tokyo Electronics Co. Ltd., Kokubunji, Tokyo, Japan

Funding: JSPS KAKENHI Grant Number JP18K11925
The non-evaporable getter (NEG) coating has been developed in CERN to make a beam pipe act as a distributed vacuum pump by coating the getter materials with the ability to adsorb/absorb gas molecules on the beam pipe surface. The NEG coating materials used in the LHC are alloys of titanium, zirconium, and vanadium. In high-power beam accelerators, titanium has been used as the beam pipe chamber material due to its low radio activation characteristics. The ordinal titanium surface has no getter function because it is covered with a titanium oxide film. The new technique, which removes the titanium-oxide surface by some methods, such as baking or sputtering, has been investigated. The dependence of the surface oxide film and the getter characteristics on the baking temperature have been measured. Also, by sputtering the inner surface of the titanium chamber, clear evidence that shows the chamber acts as a vacuum pump has been obtained. Furthermore, the NEG coating on the pure titanium surface can suppress the rapid decrease of the sticking probability by the repeated air purge and reactivation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB337

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paper received ※ 14 May 2021 paper accepted ※ 25 June 2021 issue date ※ 19 August 2021

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WEPAB349

Design of a Circular Waveguide TM₀₁ Mode Launcher with Wire Loop Feed

GUI, coupling, detector, simulation

3517

A. Chittora
BITS Pilani, Sancoale, India

In Accelerator technology, RF power couplers are important component to couple RF signal to travelling wave structure. Circular waveguide TM₀₁ mode is one of the symmetric modes, that is suitable to use for RF coupling. TM₀₁ mode launcher is used as an RF coupler in Accelerator technology*. Design of a compact circular waveguide TM₀₁ mode-launcher is presented in this paper. The design is based on the principle of magnetic field coupling between a wire loop and TM₀₁ mode of circular waveguide. The mode launcher exhibits high efficiency and 3.1% bandwidth at 3.2 GHz frequency with both circular and elliptical loop. Performance of the mode launcher is experimentally verified and simulated S-parameters agree with the measured results. The mode launcher is of compact size and is suitable for efficient excitation of TM₀₁ mode in circular waveguide and travelling wave structures. The launcher is also useful for cold testing of high power microwave antennas and Radars.
* M. Forno, "Design of a high power TM₀₁ mode launcher optimized for manufacturing by milling." 2016.

Poster WEPAB349 [1.135 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB349

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 20 August 2021

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WEPAB360

Future Prospective for Bent Crystals in Accelerators

lattice, collimation, scattering, SRF

3545

M. Romagnoni
INFN-Ferrara, Ferrara, Italy
M. Romagnoni
Universita’ degli Studi di Milano, Milano, Italy

Super magnet dipoles employed to steer high energy particle beams are massive instruments requiring cryogenic cooling and featuring large energy consumption. A bent crystal has the potential in a few millimeters to deflect 100-1000 GeV particle beams as much as an hundreds-tesla magnetic dipole. Indeed, within the lattice of a crystal, large electric fields up to several GeV/cm are present. Positive charged particles can be efficiently channeled between two adjacent lattice planes, thus following their curvature. These features and the possibility to selectively affect only the portion of the beam intercepting the crystal led to the proposal of exploiting bent crystals for several purposes, such as the collimation of ions at LHC. In this scheme, the particles on the beam halo instead of being scattered by tens-centimeters long collimators are directly separated from the beam using a 4 mm long silicon crystal. The production of a bent crystal suitable for installation in the LHC beamline requires strict control over lattice features and bending apparatus. The results obtained by the years long research of the INFN research team in Ferrara are presented in this work.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB360

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paper received ※ 14 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021

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WEPAB364

Third-Generation CERN n_TOF Spallation Target: Final Design and Examinations of Irradiated Prototype

target, neutron, radiation, proton

3555

R. Esposito, O. Aberle, M. Calviani, T. Coiffet, M.D. Crouvizier, R. Franqueira Ximenes, V. Maire, A.T. Perez Fontenla, M.A. Timmins
CERN, Geneva, Switzerland

The new neutron spallation target for the CERN neutron Time-Of-Flight (n_TOF) facility is based on a nitrogen-cooled Pb core impacted by short high-intensity proton beam pulses. An extensive material characterization campaign has been carried out to define the constitutive behavior of lead and assess its response under pulsed proton beam irradiation. The activities carried out include a beam irradiation test in the CERN HiRadMat facility. The tests and inspections performed show a robust behavior of the core material during operation and prominent static hardening recovery already at room temperature.

Poster WEPAB364 [1.011 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB364

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paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021

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WEPAB367

Bubble Generation in the SNS 2 MW Mercury Target

target, injection, proton, operation

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.

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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

operation, 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.

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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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WEPAB378

Near-Infrared Laser System for Dielectric Laser Acceleration Experiments at SINBAD

laser, electron, timing, acceleration

3596

C. Mahnke, U. Grosse-Wortmann, I. Hartl, C.M. Heyl, Y. Hua, T. Lamb, Y. Ma, C. Mohr, J. Müller, S.H. Salman, S. Schulz, C. Vidoli
DESY, Hamburg, Germany
H. Çankaya
CFEL, Hamburg, Germany

The technique of dielectric laser acceleration (DLA) utilizes the strong field gradients generated by intense laser light near the surfaces of microscopic photonic structures, possibly allowing compact accelerator devices. We report on the infrared laser system at the SINBAD facility at DESY, where first DLA experiments with relativistic electrons pre-accelerated by the ARES linear accelerator started in late 2020. We constructed a low-noise Holmium fiber oscillator producing pulses at a wavelength of 2050 nm, seeding a Ho:YLF regenerative amplifier. Pulses of 2 mJ and 2 ps duration from the amplifier are transported over a distance of about 30 m to the DLA interaction point. The laser system is synchronized to the accelerator by locking the laser repetition rate to an RF master oscillator using an all-digital phase-locked loop, giving a residual timing jitter of about 45 fs. The digital locking scheme allows precise shifting of the relative timing between laser pulses and electrons without need for a dedicated optical delay line. It is planned to lock the system to the UV photocathode laser by means of an optical cross correlator further to improve the locking performance.

Poster WEPAB378 [1.445 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB378

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

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WEPAB380

Measurements of Field Emission Induced Optical Spectra

alignment, radiation, site, electron

3602

R.C. Peacock, G. Burt
Lancaster University, Lancaster, United Kingdom
S. Calatroni, W. Wuensch
CERN, Meyrin, Switzerland

Field emission induced optical spectra in a dc electrode system have been measured using a spectrometer and CCD camera system in order to gain insight into the nature of field emissions sites. Spectra were measured from between 2 ridged parallel copper electrodes with a gap ranging from 60µm to 100µm and a bias voltage of up to 8000V under high vacuum conditions. A strong correlation between the light intensity of the spectra and the measured field emitted current was observed as a function of applied voltage. A characteristic broadband spectrum ranging from 550nm and 850nm wavelength was observed but there were important features which varied as a function of observation angle, polarity, and conditioning state and also with time. Possible causes of the optical spectra being considered include black body radiation, optical transition radiation and cathode luminescence of copper. Further experiments are ongoing with an improved optical setup to increase optical alignment for measurements with different materials of electrodes, developing further understanding of the cause of the optical spectra, to provide understanding into characteristics and evolution of emission sites.

Poster WEPAB380 [1.158 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB380

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

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WEPAB390

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

plasma, vacuum, target, operation

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.

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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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WEPAB399

Applications of the Local Observable in Future Optics Measurements in HL-LHC and PETRA III

optics, lattice, injection, quadrupole

3642

A. Wegscheider, R. Tomás García
CERN, Meyrin, Switzerland

Phase advances among four nearby beam position monitors in a circular accelerator can be used to calculate a local observable of quadrupolar lattice imperfections. This work explores the applicability of this local observable to two different circular accelerators: PETRA III, a synchrotron light source, and the LHC, a hadron collider as well as its upgrade project HL-LHC. MADX simulations for important optics settings are performed, showing that the local observable can detect strong error sources. This is of particular interest in important regions of the accelerators like the LHC’s interaction regions and PETRA III’s experimental hall.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB399

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 12 August 2021

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WEPAB401

Study for Alternative Cavity Wall and Inductive Insert Material

proton, storage-ring, impedance, simulation

3650

C.E. Taylor, C.-F. Chen, T.W. Hall, E. Henestroza, J.T.M. Lyles, J. Upadhyay
LANL, Los Alamos, New Mexico, USA
S. Biedron, M.A. Fazio, S.I. Salvador, T.J. Schaub
UNM-ECE, Albuquerque, USA

Funding: Contract No. 89233218CNA000001, supported by the U.S. Department of Energy’s National Nuclear Security Administration (NNSA), for the management and operation of Los Alamos National Laboratory (LANL).
The goal of this work was to develop a solution to the problem of longitudinal beam instability. Beam instability has been a significant problem with storage rings’ performance for many decades. The proton storage ring (PSR) at the Los Alamos Neutron Science Center (LANCE) is no exception. To mitigate the instability, it was found that ferrite inductive inserts can be used to bunch the protons that are diverging due to the electron background. The PSR was the first storage ring to successfully use inductive inserts to mitigate the longitudinal instability with normal production beams. However, years later new machine upgrades facilitate shorter, more intense beams to meet the needs of researchers. The ferrite inserts used to reduce the transverse instabilities induce a microwave instability with the shorter more intense proton beam. This study investigates alternative magnetic materials for inductive inserts in particle beam storage rings, including the necessary engineering for maintaining the ideal temperature during operation.
’ tjschaub@unm.edu

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB401

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paper received ※ 29 May 2021 paper accepted ※ 02 July 2021 issue date ※ 15 August 2021

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WEPAB412

Use of a Noise IoT Detection System to Measure the Environmental Noise in Taiwan Light Source

monitoring, real-time, network, site

3671

P.J. Wen, S.P. Kao, S.Y. Lin, Y.C. Lin
NSRRC, Hsinchu, Taiwan

In the past, the method of general noise monitoring altered little; noise was still measured with a human hand-held mobile device, or the measurement at fixed sites was made using traditional analogue data-storage equipment. In recent years, with the rapidly improved network transmission capabilities, the development of a small noise-detection IoT system allows the detection data to be transmitted wirelessly without need for human strength measurements, and records noise information. The statistics of subsequent noise data become a basis for analysis and improvement. Taiwan Light Source (TLS) beamlines have many vacuum pumps, cooling pumps, liquid-nitrogen pressure-relief systems, computer servers etc. that generate much noise. This study is expected to prepare for installation of noise detection. The system uses a noise-detection box to detect, to disclose louder locations, to collect noise data, to determine the source and type of noise source, and to provide information to reduce the noise of the working environment. The TLS noise-detection results find that the inner-ring area has less noise and are more stable than the outer ring area.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB412

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paper received ※ 14 May 2021 paper accepted ※ 24 June 2021 issue date ※ 27 August 2021

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THXB01

3D Tracking of a Single Electron in IOTA

electron, synchrotron, storage-ring, radiation

3708

A.L. Romanov, S. Nagaitsev, J.K. Santucci, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
N. Kuklev, I. Lobach
University of Chicago, Chicago, Illinois, USA

High-resolution observations of single-particle dynamics have potential as a powerful tool in the diagnostics, tuning and design of storage rings. We are presenting the results of experiments with single electrons that were conducted at Fermilab’s IOTA ring to explore the feasibility of this approach. A set of sensitive, high-resolution digital cameras was used to detect the synchrotron radiation emitted by an electron, and the resulting images were used to reconstruct the time evolution of oscillation amplitudes in all three degrees of freedom. From the evolution of the oscillation amplitudes, we deduce transverse emittances, momentum spread, damping times, beam energy and estimated residual-gas density and composition. To our knowledge, this is the first time that the dynamics of a single particle in a storage ring has been tracked in all three dimensions. We discuss farther development of a single particle diagnostics that may allow reconstruction of its turn-by-turn coordinates over macroscopic periods of time facilitating ultra-precise lattice diagnostics and direct benchmarking of tracking codes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB01

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paper received ※ 24 May 2021 paper accepted ※ 29 July 2021 issue date ※ 11 August 2021

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THXC06

Design and Measurements of an X-Band 8 MeV Standing-Wave Electron Accelerator

electron, bunching, gun, linac

3744

F. Liu, H.B. Chen, J. Shi, C.-X. Tang, H. Zha
TUB, Beijing, People’s Republic of China

X-band low-energy electron linear accelerators are attractive to industrial and medical applications due to the compact size. In this work we present tests of an 8 MeV X-band accelerator for industrial use. It adopts the coaxial coupling standing wave structure working at 9300 MHz. The accelerator length is 50 cm including the cavity, thermal gun, and electron window. Dedicated bunching cells are designed to reduce the energy spread. In the high power tests, the accelerator was able to generate the electron beam with RMS energy spread less than 1% (beam energy: 8.1 MeV, peak current: 45 mA). Combining features of compact size and the low energy spread, this X-band accelerator design is valuable for various applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXC06

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

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THPAB022

Possibilities for Upgrading to Polarized SuperKEKB

electron, polarization, lattice, cathode

3799

Z.J. Liptak, M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
J.M. Roney
Victoria University, Victoria, B.C., Canada

The SuperKEKB accelerator is currently in operation in Tsukuba, Japan, with a planned long shutdown in 2026. Among the possible upgrades being considered during this period is the change to a polarized electron beam in the High Energy Ring. Such a change would require modifications in the source generation and transport, geometrical and lattice variations to provide spin rotation, and polarimetry. A Polarized SuperKEKB Working Group has been formed from members of the Belle II experiment and the SuperKEKB accelerator team to investigate the possibilities and challenges of these modifications. This talk lays out the goals of the proposed upgrade, considers the necessary changes to the existing accelerator and their feasibility and lays out the physics motivation behind such an effort.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB022

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 29 August 2021

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THPAB025

A Proposed Beam-Beam Test Facility COMBINE

collider, electron, linac, beam-beam-effects

3802

E.A. Nissen, G.A. Krafft
JLab, Newport News, Virginia, USA
J.R. Delayen
ODU, Norfolk, Virginia, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, license to publish or reproduce this manuscript.
The COmpact Machine for Beam-beam Interactions in Non-Equilibrium systems (COMBINE) is a proposed, dedicated, beam-beam test facility. The base design would make use of a pair of identical octagonal rings (2.5 meters per side) one rotated 180 degrees from the other, meeting at their common interaction point. These would be fed by an electron gun producing up to 125 keV electrons. The low energy will allow for beam-beam tune shifts commensurate with existing colliders, some linac-ring type systems, and will also allow for an exploration of the predicted effects of gear-changing, which would be performed using a variable pathlength scheme. The low energy, and small size will allow for cost effective research, simulation code benchmarking, as well as training opportunities for students.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB025

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paper received ※ 20 May 2021 paper accepted ※ 01 September 2021 issue date ※ 16 August 2021

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THPAB042

Bending Radius Limits of Different Coated REBCO Conductor Tapes - An Experimental Investigation with Regard to HTS Undulators

undulator, collider, wiggler, positron

3837

S.C. Richter, A. Bernhard, A. Drechsler, A.-S. Müller, B. Ringsdorf, S.I. Schlachter
KIT, Karlsruhe, Germany
S.C. Richter, D. Schoerling
CERN, Geneva, Switzerland

Funding: This work has been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Research (grant no. 05E18CHA).
Compact FELs require short-period, high-field undulators in combination with compact accelerator structures to produce coherent light up to X-rays. Likewise, for the production of low emittance positron beams for future lepton colliders, like CLIC or FCC-ee, high-field damping wigglers are required. Applying high-temperature superconductors in form of coated REBCO tape conductors allows reaching higher magnetic fields and larger operating margins as compared to low-temperature superconductors like Nb-Ti or Nb₃Sn. However, short undulator periods like 13 mm may require bending radii of the conductor smaller than 5 mm inducing significant bending strain on the superconducting layer and may harm its conducting properties. In this paper, we present our designed bending rig and experimental results for REBCO tape conductors from various manufacturers and with different properties. Investigated bending radii reach from 20 mm down to 1 mm and optionally include half of a helical twist. To represent magnet winding procedures, the samples were bent at room temperature and then cooled down to T = 77 K in the bent state to test for potential degradation of the superconducting properties.

Poster THPAB042 [1.871 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB042

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

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THPAB049

Modeling the Magnetic Field of the LCLS-I Undulator for THz@PITZ

undulator, FEL, simulation, vacuum

3855

M. Krasilnikov, X. Li, A. Lueangaramwong, F. Mueller, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A. Brachmann, H.-D. Nuhn
SLAC, Menlo Park, California, USA
M. Tischer, P. Vagin
DESY, Hamburg, Germany

Funding: This work was supported by the European XFEL research and development program
An accelerator-based THz source for pump-probe experiments at the European XFEL is under development at the Photo Injector Test Facility at DESY in Zeuthen (PITZ). For the proof-of-principle experiments an LCLS-I undulator is planned to be installed downstream of the PITZ accelerator. The fields of the undulator module 26 have been re-measured at DESY in Hamburg and the results are consistent with earlier SLAC measurements. A model for 3D field reconstruction based on the undulator magnetic measurements has been developed. It includes also a horizontal gradient of the vertical field. Tracking of the 17 MeV/c beam has revealed that the transverse gradient will lead to a significant off-axis trajectory in the horizontal plane. This offset has to be corrected with a steering coil, the design of which is also presented. The performance of the THz generation with the correction coil is discussed as well.

Poster THPAB049 [1.409 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB049

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

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THPAB062

Long-Wave IR Terawatt Laser Pulse Compression to Sub-Picoseconds

laser, simulation, FEM, plasma

3893

I. Pogorelsky, M. Babzien, M.A. Palmer, M.N. Polyanskiy
BNL, Upton, New York, USA

Funding: U.S. Department of Energy under contract DE-SC0012704
We report an experiment and simulations on post-compression of 2 ps, 0.15 TW CO₂ laser pulses to 480 fs, ~0.25 TW by means of a self-phase modulation accompanied by a negative group dispersion in KCl and BaF2 optical slabs. In addition, down to 130 fs fine pulse structure, but at lower conversion efficiency, has been observed through self-compression in a bulk NaCl crystal. The obtained results surpass by far previous achievements in the ultra-fast long-wave IR laser technology

Poster THPAB062 [2.675 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB062

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paper received ※ 12 May 2021 paper accepted ※ 18 June 2021 issue date ※ 24 August 2021

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THPAB071

Physics Goals of DWA Experiments at FACET-II

wakefield, quadrupole, acceleration, focusing

3922

J.B. Rosenzweig, H.S. Ancelin, G. Andonian, A. Fukasawa, C.E. Hansel, G.E. Lawler, W.J. Lynn, N. Majernik, J.I. Mann, P. Manwani, Y. Sakai, O. Williams, M. Yadav
UCLA, Los Angeles, California, USA
S.V. Baryshev
Michigan State University, East Lansing, Michigan, USA
S. Baturin
Northern Illinois University, DeKalb, Illinois, USA
M.J. Hogan, B.D. O’Shea, D.W. Storey, V. Yakimenko
SLAC, Menlo Park, California, USA

Funding: This work supported by DOE HEP Grant DE-SC0009914,
The dielectric wakefield acceleration (DWA) program at FACET produced a multitude of new physics results that range from GeV/m acceleration to the discovery of high field-induced conductivity in THz waves, and beyond, to a demonstration of positron-driven wakes. Here we review the rich program now developing in the DWA experiments at FACET-II. With increases in beam quality, a key feature of this program is extended interaction lengths, near 0.5 m, permitting GeV-class acceleration. Detailed physics studies in this context include beam breakup and its control through the exploitation of DWA structure symmetry. The next step in understanding DWA limits requires the exploration of new materials with low loss tangent, large bandgap, and improved thermal characteristics. Advanced structures with photonic features for mode confinement and exclusion of the field from the dielectric, as well as quasi-optical handling of coherent Cerenkov signals is discussed. Use of DWA for laser-based injection and advanced temporal diagnostics is examined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB071

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

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THPAB113

The Extended Operative Range of the LNF LINAC and BTF Facilities

linac, positron, target, klystron

3987

L.G. Foggetta, M. Belli, B. Buonomo, F. Cardelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, D. Di Giovenale, C. Di Giulio, G. Piermarini, L.A. Rossi, S. Strabioli, R. Zarlenga
INFN/LNF, Frascati, Italy

Funding: These activities has been partially supported by AIDA-2020 Grant Agreement 654168 and ERAD projects.
In 2020 the INFN-LNF LINAC and BTF have performed long-term runs for test beams and fixed-target experiments. The scientific needs of these items have been leading our groups to continuous improvements of the LINAC operative range both in pulse time at maximum energy and on the minimum transported energy, until the reset to DAΦNE injections at the beginning of 2021. We will also show the BTF recent developments in the transported beams and the second line installation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB113

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

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THPAB126

Operational Experience and Characterization of a Superconducting Transverse Gradient Undulator for Compact Laser Wakefield Accelerator-Driven FEL

laser, electron, undulator, FEL

4009

K. Damminsek, A. Bernhard, J. Gethmann, A.W. Grau, A.-S. Müller, Y. Nie, M.S. Ning, S.C. Richter, R. Rossmanith
KIT, Karlsruhe, Germany

A 40-period superconducting transverse gradient undulator (TGU) has been designed and fabricated at Karlsruhe Institute of Technology (KIT). Combining a TGU with a Laser Wakefield Accelerator (LWFA) is a potential key for realizing an extremely compact Free Electron Laser (FEL) radiation source. The TGU scheme is a viable option to compensate the challenging properties of the LWFA electron beam in terms of beam divergence and energy spread. In this contribution, we report on the operational experience of this TGU inside its own cryostat and show the current status of the TGU and the further plan for experiments. This work is supported by the BMBF project 05K19VKA PlasmaFEL (Federal Ministry of Education and Research).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB126

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

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THPAB130

Design of a Very Low Energy Beamline for NA61/SHINE

target, hadron, simulation, optics

4017

C.A. Mussolini, N. Charitonidis
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
Y. Nagai
Colorado University at Boulder, Boulder, Colorado, USA
Y. Nagai
ELTE, Budapest, Hungary
E.D. Zimmerman
CIPS, Boulder, Colorado, USA

A new, low-energy beamline branch is currently under consideration for the H₂ beamline at the CERN North Area. This new branch would extend the capabilities of the current infrastructure enabling the study of particles in the very low, 1-13 GeV/c, momentum range. The design of this new beamline involves various stages. Firstly, a study of the secondary targets to maximise the yield of secondary hadrons. Secondly, the development of high acceptance transverse optics with high momentum resolution on the order of a few %. Finally, we discuss the first considerations on instrumentation to enable particle identification and background rejection. The first experiment to profit from this new line could be NA61/SHINE, but other possible future fixed target experiments or test-beams installed in the downstream zones could also use the low-energy particles provided. The aim is to arrive at a complete design of this branch by the end of 2021, which, pending the approval of the CERN scientific committees, could be envisaged for construction after 2024. This timescale is compatible with requests for measurements by various large international collaborations, in the next 10-year horizon.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB130

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

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THPAB143

M2 Experimental Beamline Optics Studies for Next Generation Muon Beam Experiments at CERN

optics, hadron, detector, collider

4041

D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, G.L. D’Alessandro, A. Gerbershagen, E. Montbarbon, C.A. Mussolini, E.G. Parozzi, B. Rae, B.M. Veit
CERN, Geneva, Switzerland
L. Gatignon
Lancaster University, Lancaster, United Kingdom

In the context of the Physics Beyond Colliders Project, various new experiments have been proposed for the M2 beamline at the CERN North Area fixed target experimental facility. The experiments include MUonE, NA64µ, and the successor to the COMPASS experiment, tentatively named AMBER/NA66. The AMBER/NA66 collaboration proposes to build a QCD facility requiring conventional muon and hadron beams for runs up to 2024 in the first phase of the experiment. MUonE aims to measure the hadronic contribution to the vacuum polarization in the context of the (gµ-2) anomaly with a setup longer than 40 m and a 160 GeV/c high intensity, low divergence muon beam. NA64µ is a muon beam program for dark sector physics requiring a 100 - 160 GeV/c muon beam with a 15-25 m long setup. All three experiments request similar beam times up to 2024 with compelling physics programs, which required launching extensive studies for integration, installation, beam optics, and background estimations. The experiments will be presented along with details of the studies performed to check their feasibility and compatibility with an emphasis on the updated optics for these next-generation muon beam experiments.

Poster THPAB143 [14.259 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB143

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

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THPAB151

The Advantage of Cold Electron Source in Electron Diffraction

electron, simulation, FEL, ion-source

4053

J. Liu, H. Luo
SWUST, Mianyang City, Sichuan Province, People’s Republic of China

In this paper, a model for discussing the influence of transverse coherence of electron beams on electron diffraction is established. With reference to Fedele’s thermal-wave model, the transverse coherence length is introduced into this model to characterize the transverse coherence of electron beams. The simulation results show that the transverse coherence of electron beams has a significant influence on electron diffraction, and the cold electron source with high transverse coherence has an obvious advantage in electron diffraction.

Poster THPAB151 [0.647 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB151

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paper received ※ 15 May 2021 paper accepted ※ 21 June 2021 issue date ※ 25 August 2021

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THPAB172

Bunch Luminosity Variations in LHC Run 2

luminosity, emittance, injection, operation

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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THPAB175

nuSTORM Accelerator Challenges and Opportunities

collider, storage-ring, target, emittance

4104

C.T. Rogers, J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
N. Gall
CERN, Meyrin, Switzerland
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The nuSTORM facility uses a stored muon beam to generate a neutrino source. Muons are captured and stored in a storage ring using stochastic injection. The facility will aim to measure neutrino-nucleus scattering cross-sections with uniquely well-characterized neutrino beams; to facilitate the search for sterile neutrino and other Beyond Standard Model processes with exquisite sensitivity, and to provide a muon source that makes an excellent technology test-bed required for the development of muon beams capable of serving as a multi-TeV collider. In this paper, we describe the latest status of the development of nuSTORM, the R&D needs, and the potential for nuSTORM as a Muon Collider test facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB175

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

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THPAB181

AI-ML Developments for the ATLAS Ion Linac Facility

rfq, operation, linac, 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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THPAB182

DC-280 Cyclotron for Factory of Super Heavy Elements, Experimental Results

cyclotron, acceleration, ECR, injection

4126

V.A. Semin, S.L. Bogomolov, K. Gikal, G.G. Gulbekyan, I.A. Ivanenko, I.V. Kalagin, N.Yu. Kazarinov, V.I. Mironov
JINR, Dubna, Moscow Region, Russia
L.A. Pavlov
JINR/FLNR, Moscow region, Russia

The DC280 is the high current cyclotron with design beam intensities up to 10 pµA for ions with energy from 4 to 8 MeV/nucleon. It was developed and created at the FLNR JINR. The first was extracted from the cyclotron on January 17, 2019. Experiments on acceleration of 12C, 40Ar, 48Ca, 48Ti, 52Cr and 84Kr beams production were carried out. The following intensities of accelerated beam have been achieved: 10 pµA for 12C+2; 9,2 pµA for 40Ar+7; 7,1 pµA for 48Ca+10; 1,0 pµA for 48Ti+10; 2,4 pµA for 52Cr+10 and 1.43 pµA for 84Kr+14;. The accelerator has worked more than 9000 hours. The work of accelerator was stable and high efficiency. The total acceleration efficiency from ion source to transport channel was about 46%.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB182

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paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 21 August 2021

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THPAB189

New Techniques to Compute the Linear Tune

collider, simulation, damping, betatron

4142

G. Russo, M. Giovannozzi
CERN, Geneva, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Tune determination in numerical simulations is an essential aspect of nonlinear beam dynamics studies. In particular, because it allows probing whether an initial condition is close to resonance, and it enables assessment of the stability of the orbit, i.e. whether the motion is regular or chaotic. In this paper, results of recently developed techniques to obtain accurate tune computation from numerical simulation data are presented and discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB189

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paper received ※ 18 May 2021 paper accepted ※ 26 July 2021 issue date ※ 19 August 2021

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THPAB210

Extrapolated Range for Low Energy Electrons (< 1 keV)

electron, simulation, multipactoring, GUI

4201

C. Inguimbert, M.B. Belhaj, Q. Gibaru
ONERA, Toulouse, France
Q. Gibaru, D. Lambert, M. Raine
CEA, Arpajon, France
Q. Gibaru
CNES, PARIS, France

Funding: ONERA- DPHY, 2 avenue E. Belin, 31055 Toulouse, France CEA, DAM, DIF, 91297 Arpajon, France CNES, 18 av. E. Belin, 31055 Toulouse, France
The Secondary Electron Emission (SEE) process plays an important role in the performance of various devices. Mitigating the multipactor phenomenon that may occur in radio-frequency components is a concern in many fields such as space technologies or electron microscopy. SEE is also a concern in the accelerator physics community, where the beam lines stability can strongly be affected by this phenomenon*,**. In that scope, the escaped depth and thus the range of emitted electrons is of great interest. Our goal, by means of simulations is to provide a better knowledge of SEE. We have developed a Monte Carlo electron transport code for low energy electrons [~eV, ~10keV], that is part of the Dec. 2020 release of GEANT4***. It has been used to study the practical range of low energy electrons. Our goal is to formulate, below ~10 keV, an analytic range vs. energy expression, and to relate it to fundamental physcial parameters such as the mean free paths of electrons in matter. The goal is to provide simple practical extrapolated range formula that can help to understand SEE phenomenon.
* M. Mostajeran et al. J. of Instr. 5 (2010)
** C. Y. Vallgren et al. Phys. Rev. Accel. Beam 14 (2011)
*** Q. Gibaru et al. Nuc. Inst. And Met. 487 (2021)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB210

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paper received ※ 10 May 2021 paper accepted ※ 23 June 2021 issue date ※ 27 August 2021

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THPAB211

Monte Carlo Simulation of 3D Surface Morphologies for Secondary Electron Emission Reduction

electron, simulation, multipactoring, GUI

4204

Q. Gibaru, M.B. Belhaj, C. Inguimbert
ONERA, Toulouse, France
Q. Gibaru, D. Lambert, M. Raine
CEA, Arpajon, France
Q. Gibaru
CNES, PARIS, France

Low energy electrons of few tens of eV may cause Multipactor breakdowns in waveguides driven by the Secondary Electron Emission Yield (SEY) of the walls. This risk is lowered by using low emissive surfaces and this topic has been studied experimentally and with numerical simulations. The dependence of the SEY on surface properties is well known*. Surface morphology has been widely used to reduce the SEY by forming roughness patterns on the surface**. All patterns do not have the same efficiency so their analysis in terms of SEY is relevant. Monte-Carlo simulation codes can be used to study the processes behind the SEY. The MicroElec module of GEANT4 has recently been extended with more materials and processes and validated with experimental data for SEY calculations**. In this work, simulation results are shown for a bulk sample capped with different roughness patterns. The effects of the shape parameters on the SEY are studied for typical dimensions between 20 µm and 100 µm. The results are checked with experimental SEY measurements on samples with similar roughness patterns.
*:T Gineste et al, Appl Surf Sci 359 (2015) 398-404
**:J Pierron et al, J Appl Phys 124 (2018) 095101
***:Q. Gibaru, C. Inguimbert, P. Caron, M. Raine, D. Lambert, J. Puech, NIM B. 487 (2021) 66-77

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB211

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paper received ※ 12 May 2021 paper accepted ※ 23 June 2021 issue date ※ 17 August 2021

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THPAB214

Recent BDSIM Related Developments and Modeling of Accelerators

laser, simulation, radiation, shielding

4208

L.J. Nevay, A. Abramov, S.E. Alden, S.T. Boogert, G. D’Alessandro, S.M. Gibson, H. Lefebvre, W. Shields, S.D. Walker
JAI, Egham, Surrey, United Kingdom
A. Abramov, G. D’Alessandro, C. Hernalsteens
CERN, Meyrin, Switzerland
E. Gnacadja, C. Hernalsteens, E. Ramoisiaux, R. Tesse
ULB, Bruxelles, Belgium
S. Liu
DESY, Hamburg, Germany

Funding: This work is supported by the STFC (UK) grants: JAI ST/P00203X/1, HL-LHC-UK1 ST/N001583/1, HL-LHC-UK2 ST/T001925/1, and ST/P003028/1.
Beam Delivery Simulation (BDSIM) is a program based on Geant4 that creates 3D radiation transport models of accelerators from a simple optical description in a vastly reduced time frame with great flexibility. It also uses ROOT and CLHEP to create a single simulation model that can accurately track all particle species in an accelerator to predict and understand beam losses, secondary radiation, dosimetric quantities and their origin. BDSIM provides a library of scalable generic geometry for a variety of applications. Our Python package, Pyg4ometry, allows rapid preparation and conversion of geometries for BDSIM and other radiation transport simulations including FLUKA. We present a broad overview of BDSIM developments related to a variety of experiments at several facilities. We present a model of the forward experiment FASER at the LHC, CERN where the geometry is composited from multiple sources using Pyg4ometry. The analysis of particle history is presented as well as production mechanisms. We also present the application of recently introduced laser interactions in Geant4 to Compton photons from a laserwire diagnostic at the ATF2.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB214

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paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 22 August 2021

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THPAB240

Combined Effect of IBS and Impedance on the Longitudinal Beam Dynamics

emittance, simulation, lattice, wakefield

4274

A. Blednykh
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
B. Bacha, G. Bassi, T.V. Shaftan, V.V. Smaluk
BNL, Upton, New York, USA
M. Borland, R.R. Lindberg
ANL, Lemont, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The horizontal/vertical emittances, the bunch length, and the energy spread increase have been studied in the NSLS-II as a function of a single bunch current. The monotonic growth of the horizontal emittance dependence and the energy spread dependence on the single bunch current below the microwave instability threshold can be explained by the Intrabeam Scattering Effect (IBS). The IBS effect results in an increase in the bunch length and the microwave instability thresholds. It was observed experimentally by varying the vertical emittance. To compare with experimental data, particle tracking simulations have been performed with the ELEGANT code including both IBS and the total longitudinal wakefield calculated from the 3D electromagnetic code GdfidL. The same particle tracking simulations have also been applied for the APS-U project, where IBS is predicted to produce only a marginal effect.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB240

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paper received ※ 20 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021

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THPAB251

Efficient Terahertz Generation by Tilted-Pulse-Front Pumping in Lithium Niobate for the Split-Ring Resonator Experiment at FLUTE

electron, laser, diagnostics, vacuum

4299

M. Nabinger, E. Bründermann, S. Funkner, B. Härer, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, J. Schäfer, T. Schmelzer, N.J. Smale
KIT, Karlsruhe, Germany
M.M. Dehler, R. Ischebeck, M. Moser, V. Schlott
PSI, Villigen PSI, Switzerland
T. Feurer, M. Hayati, Z. Ollmann
Universität Bern, Institute of Applied Physics, Bern, Switzerland

Funding: This work is co-funded via the European Union’s H₂020 research and innovation program, GA No 730871, ARIES.
A compact, longitudinal diagnostics for fs-scale electron bunches using a THz electric-field transient in a split-ring resonator (SRR) for streaking will be tested at the Ferninfrarot Linac- Und Test- Experiment (FLUTE). For this new streaking technique, intensive THz pulses are required, which will be generated by laser-based optical rectification. We present a setup for generating THz pulses using tilted-pulse-front pumping in lithium niobate at room temperature. Excited by an 800 nm Ti:Sa pump laser with 35 fs bandwidth-limited pulse length, conversion efficiencies up to 0.027% were achieved. Furthermore, the status of the SRR experiment is shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB251

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

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THPAB282

Optimization Design of Four-Point Vibration Isolation Support for Spallation Neutron Source Vibration Magnet

ISOL, dipole, damping, extraction

4352

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

Chinese spallation neutron source (CSNS) RCS of the dipole magnets by 25 Hz sinusoidal alternating current (AC) with dc bias field, because the magnet will produce eddy current effect caused by the vibration, this safe and reliable operation of the long-term impact of magnets, so need to CSNS/RCS dipole magnets, a support system for dynamic characteristic research and the performance of vibration isolation design. The mechanical model of ac dipole magnet and support system is first established, and ANSYS theoretical modal analysis and experimental modal verification are carried out. On this basis, vibration isolation parameters of the four-point support system are studied. The theoretical analysis and the experimental results of modal parameters are consistent, which shows that the ANSYS analysis model is correct and reliable. The dynamic system parameter design method established in this paper can be applied to various equipment of AC power accelerator. The final experimental verification shows that the total displacement amplitude of the isolator to the Y direction of the magnet on the magnetic support decreases by 62.3%.

Poster THPAB282 [0.426 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB282

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paper received ※ 16 May 2021 paper accepted ※ 02 September 2021 issue date ※ 27 August 2021

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THPAB292

Dynamic Pressure in the LHC: Detection of Ions Induced by Ionization of Residual Gas by the Proton Beam and by the Electron-Cloud

electron, proton, vacuum, ECR

4377

S. Bilgen, B. Mercier, G. Sattonnay
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
V. Baglin
CERN, Meyrin, Switzerland

Ultra-High Vacuum is an essential requirement to achieve design performances and high luminosities in high-energy particle colliders. Consequently, the understanding of the dynamic pressure evolution during accelerator operation is fundamental to provide solutions to mitigate pressure rises induced by multiple effects leading to beam instabilities. For the LHC, the appearance of instabilities may be due to the succession of several phenomena: (i) the induced desorption of gases adsorbed on the surfaces leading to pressure rises; (ii) the creation of secondary particles (ions, electrons); (iii) the production of the so-called Electron Cloud build-up by multipacting effect. This work aims to investigate some fundamental phenomena which drive the dynamic pressure in the LHC, namely the effects induced by electrons and ions interacting with the copper surface of the beam screens. Electron and ion currents, as well as pressure, were recorded in situ in the Vacuum Pilot Sector (VPS*) located on the LHC ring during the RUN II. By analyzing the results, more ions than expected were detected and the interplay between electrons, ions, and pressure changes was investigated.
* The LHC Vacuum Pilot-Sector Project, B. Henrist, V. Baglin, G. Bregliozzi, and P. Chiggiato, CERN, Geneva, Switzerland, Proceedings of IPAC2014, Dresden, Germany

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB292

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021

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THPAB314

Development of the Femtosecond Timing Distribution System for the Shanghai Soft X-Ray Free Electron Laser

FEL, timing, laser, FEM

4406

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

High accuracy timing and synchronization system on femtosecond timescale play an important role for free-electron laser projects such as Shanghai Soft X-ray free-electron laser facility (SXFEL), and future Shanghai high repetition rate XFEL and Extreme light facility (SHINE). To meet the high precision synchronization requirements for both facilities, an optical-based timing distribution system is absolutely necessary. Such a system distributes the laser pulse train from a locked optical master oscillator through the fiber links, which stabilized by a balance optical cross-correlator based on a periodical-poled KTiOPO4 crystal. In this paper, the recent progress and experimental results of SXFEL and SHINE timing distribution system will be reported.

Poster THPAB314 [0.351 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB314

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paper received ※ 20 May 2021 paper accepted ※ 15 July 2021 issue date ※ 22 August 2021

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THPAB317

Experiment and Simulation Study on the Capture and Acceleration Process of XiPAF Synchrotron

acceleration, synchrotron, cavity, proton

4409

Y. Li, X. Guan, X.Y. Liu, M.W. Wang, X.W. Wang, Q.Z. Xing, Y. Yang, H.J. Yao, W.B. Ye, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.L. Liu, D. Wang, Z.M. Wang, Y. Yang, M.T. Zhao
NINT, Shannxi, People’s Republic of China

The beam commissioning of the capture and acceleration process on the XiPAF (Xi’an 200MeV Proton Application Facility) synchrotron has been carried out. The efficiency of the experiment results has been compared with the simulation results. At present, the efficiency of the capture process with single-harmonic is about 73%, and the acceleration efficiency is about 82%, and the simulation results are 77% and 96% without space charge effect, respectively. In order to improve efficiency, dual-harmonic was used during the capture and acceleration process. During the experiment, the capture efficiency was increased by 5%, and the acceleration efficiency was increased by 4%. The capture efficiency decreases with the increase of the maximum RF voltages. We analyzed the reasons for the decrease in capture efficiency. In the next step, further verification will be carried out through experiments under different conditions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB317

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paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 23 August 2021

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THPAB335

Optical Phase Space Mapping Using a Digital Micro-Mirror Device

radiation, GUI, optics, controls

4439

M. Vujanovic, R.B. Fiorito, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
A.L. Kippax
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
Optical transition radiation (OTR) is routinely used to measure transverse beam size, divergence , and emittance of charged particle beams. Presented here is an experimental method, which uses micro-mirror device (DMD) to conduct optical phase space mapping (OPSM). OPSM will be a next step and significant enhancement of the measurements capabilities of an adaptive optics-based beam characterization system. For this measurements, a DMD will be used to generate a reflective mask that replicates the double slit. Since the DMD makes it possible to easily change the size, shape and position of the mask, the use of the DMD will greatly simplify OPSM and make it more flexible, faster and more useful for diagnostics applications. The process can be automated and integrated into a control system that can be used to optimize the beam transport.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB335

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paper received ※ 20 May 2021 paper accepted ※ 27 July 2021 issue date ※ 28 August 2021

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THPAB348

INFN-LASA for the PIP-II LB650 Linac

cavity, SRF, linac, cryogenics

4474

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

INFN joined the international effort for the PIP-II project at Fermilab and it’s going to contribute to the low-beta section of the PIP-II proton linac. In particular, INFN-LASA is finalizing its commitment to deliver in kind the full set of the LB650 cavities, namely 36 plus spares 5-cell cavities at 650 MHz and geometrical beta 0.61. All cavities, designed by INFN-LASA, will be produced and surface treated in industry, qualified through vertical cold test, and delivered as ready for string installation. This paper reports the status of INFN’s contribution to PIP-II and of ongoing activities toward the experimental qualifications of infrastructures and prototypes.

Poster THPAB348 [4.076 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB348

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

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THPAB351

INFN-LASA Experimental Activities on PIP-II Low-Beta Cavity Prototypes

cavity, target, SRF, superconductivity

4481

M. Bertucci, A. Bosotti, A. D’Ambros, A.T. Grimaldi, P. Michelato, L. Monaco, C. Pagani, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
A. Gresele, A. Torri
Ettore Zanon S.p.A., Nuclear Division, Schio, Italy
M. Rizzi
Ettore Zanon S.p.A., Schio, Italy

This paper reports on the first results obtained by INFN-LASA on PIP-II low-beta cavity prototypes. The goal of this activity was to validate the reference surface treatment based on Electropolishing as a bulk removal step. The cavity treatment procedures are here presented together with the strategy used for their optimization. The experimental results of cavity cold tests for a single cell prototype are presented and discussed. Having this cavity achieved the requested performance, the baseline procedure is considered as validated and a plan for a future high-Q cavity surface treatment is proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB351

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 29 August 2021

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THPAB372

SABINA: A Research Infrastructure at LNF

laser, radiation, electron, focusing

4505

L. Sabbatini, D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, B. Buonomo, S. Cantarella, F. Cardelli, E. Chiadroni, G. Costa, G. Di Pirro, F. Dipace, A. Esposito, M. Ferrario, M. Galletti, A. Gallo, A. Ghigo, L. Giannessi, A. Giribono, S. Incremona, L. Pellegrino, L. Piersanti, R. Pompili, R. Ricci, J. Scifo, A. Stecchi, A. Stella, C. Vaccarezza, A. Vannozzi, S. Vescovi, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Cianchi
INFN-Roma II, Roma, Italy
A. Doria, A. Petralia
ENEA C.R. Frascati, Frascati (Roma), Italy
L. Giannessi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S. Lupi
Sapienza University of Rome, Roma, Italy
S. Macis
La Sapienza University of Rome, Rome, Italy
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy
V. Petrillo
INFN-Milano, Milano, Italy

Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program.
SABINA (Source of Advanced Beam Imaging for Novel Applications) is a project aimed at the enhancement of the SPARC_LAB research facility. This enhancement is carried out through the following actions: first, the increase of the uptime through the consolidation of technological systems and the replacement of some critical equipment in order to limit the number and extent of faults; then, the improvement of the accelerator performances, by replacing some devices with updated ones. The effect will be greater reliability of the accelerator, which will allow it to be opened as a facility for external users, both industrial and scientific, with the goal of increasing the competitiveness of industries in a broad range of technological areas and enhancing collaborations with research institutions. The two user lines that will be implemented are a power laser target area and a THz radiation line, by using a dedicated undulator. The undulator and the THz line are also described in other contributions to this conference. A brief description of the project and potential exploitations are reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB372

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paper received ※ 24 May 2021 paper accepted ※ 01 July 2021 issue date ※ 20 August 2021

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FRXB05

Muon Ionization Cooling Experiment: Results & Prospects

emittance, solenoid, collider, proton

4528

C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A high-energy muon collider could be the most powerful and cost-effective collider approach in the multi-TeV regime, and a neutrino source based on decay of an intense muon beam would be ideal for measurement of neutrino oscillation parameters. Muon beams may be created through the decay of pions produced in the interaction of a proton beam with a target. The muons are subsequently accelerated and injected into a storage ring where they decay producing a beam of neutrinos, or collide with counter-rotating antimuons. Cooling of the muon beam would enable more muons to be accelerated resulting in a more intense neutrino source and higher collider luminosity. Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration constructed a section of an ionization cooling channel and used it to provide the first demonstration of ionization cooling. Here the observation of ionization cooling is described. The cooling performance is studied for a variety of beam and magnetic field configurations. The outlook for muon ionization cooling demonstrations is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXB05

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

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FRXC03

Modern Ultra-Fast Detectors for Online Beam Diagnostics

detector, electron, laser, FPGA

4540

M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, W. Wang, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’
Synchrotron light sources operate with bunch repetition rates in the MHz regime. The longitudinal and transverse beam dynamics of these electron bunches can be investigated and characterized by experiments employing linear array detectors. To improve the performance of modern beam diagnostics and overcome the limitations of commercially available detectors, we have at KIT developed KALYPSO, a detector system operating with an unprecedented frame rate of up to 12 MHz. To facilitate the integration in different experiments, a modular architecture has been utilized. Different semiconductor microstrip sensors based on Si, InGaAs, PbS, and PbSe can be connected to the custom-designed low noise front-end ASIC to optimize the quantum efficiency at different photon energies, ranging from near-UV, visible, and up to near-IR. The front-end electronics are integrated within a heterogeneous DAQ consisting of FPGAs and GPUs, which allows the implementation of real-time data processing. This detector is currently installed at KARA, European XFEL, FLASH, Soleil, DELTA. In this contribution, we present the detector architecture, the performance results, and the ongoing technical developments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC03

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 01 September 2021

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FRXC06

Development of the Prototype of the Cavity BPM System for SHINE

cavity, FEL, electron, controls

4552

J. Chen, Y.B. Leng, R.X. Yuan
SSRF, Shanghai, People’s Republic of China
S.S. Cao
SINAP, Shanghai, People’s Republic of China
L.W. Lai
SARI-CAS, Pudong, Shanghai, People’s Republic of China

The Shanghai high repetition rate XFEL and extreme light facility (SHINE) under construction is designed as one of the most advanced FEL facilities in the world, which will produce coherent x-rays with wavelengths from 0.05 to 3 nm and maximum repetition rate of 1MHz. In order to achieve precise, stable alignment of the electron and photo beams in the undulator, the prototype of the cavity beam position monitors (CBPM) including C-band and X-band have been designed and fabricated for the SHINE. And the requirement of the transverse position resolution is better than 200 nm for a single bunch of 100 pC at the dynamic range of ±100 µm. In this paper, we present the design of the cavity with high loaded Q and the RF front-end with low noise-figure, adjustable gain, single-stage down-conversion and phase-locked with reference clock, and also described the structure and specifications of the home-made data acquisition (DAQ) system. The construction of the experiment platform and preliminary measurement result with beam at Shanghai Soft X-ray FEL facility (SXFEL) will be addressed as well.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC06

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paper received ※ 20 May 2021 paper accepted ※ 06 July 2021 issue date ※ 17 August 2021

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