IPAC2019 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOYPLM1	Challenges to Higher Beam Power in J-PARC: Achieved Performance and Future Prospects	operation, resonance, extraction, proton	6
	S. Igarashi KEK, Ibaraki, Japan
	J-PARC is a world leading intensity frontier accelerator facility, consisting of a 400-MeV H⁻ linac, a 3-GeV Rapid Cycling Synchrotron (RCS) and a 30-GeV slow cycling Main Ring synchrotron (MR). The RCS delivered a 500 kW beam (4.2·10¹³ particles per pulse (ppp)) to the Material and Life science experimental Facility (MLF) in April of 2018, The design power of 1 MW will be delivered in the next few years. Construction of a second target station (2TS) of the MLF with beam power upgraded to 1.5 MW is now under discussion. The MR delivers proton beam to a long-baseline neutrino oscillation experiment, T2K, by fast extraction (FX) and to the hadron experimental facility by slow extraction (SX). For the FX, the maximum beam power is 475 kW and 2.5·10¹⁴ ppp, the world highest ppp in synchrotrons, and for the SX 51 kW and 5.5·10¹³ ppp with an extremely high extraction efficiency of 99.5 %. To achieve 1.3 MW beam power for the neutrino experiment, upgrades to allow operation with a higher repetition rate are planned. The talk will review recent progress of J-PARC facility by highlighting technical challenges toward higher beam power together with future prospects.
	Slides MOYPLM1 [9.193 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOYPLM1
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOZPLS2	Ion Collider Precision Measurements With Different Species	target, operation, electron, collider	28
	G.J. Marr, E.N. Beebe, I. Blackler, W. Christie, K.A. Drees, P.S. Dyer, A.V. Fedotov, W. Fischer, C.J. Gardner, H. Huang, T. Kanesue, N.A. Kling, V. Litvinenko, C. Liu, Y. Luo, D. Maffei, B. Martin, A. Marusic, K. Mernick, M.G. Minty, C. Naylor, M. Okamura, I. Pinayev, G. Robert-Demolaize, T. Roser, P. Sampson, V. Schoefer, T.C. Shrey, D. Steski, P. Thieberger, J.E. Tuozzolo, K. Zeno, I.Y. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Precedent to electron cooling commissioning and collisions of Gold at various energies at RHIC in 2018, the STAR experiment desired an exploration of the chiral magnetic effect in the quark gluon plasma (QGP) with an isobar run, utilizing Ruthenium and Zirconium. Colliding Zr-96 with Zr-96 and Ru-96 with Ru-96 create the same QGP but in a different magnetic field due to the different charges of the Zr (Z=40) and Ru (Z=44) ions. Since the charge difference is only 10%, the experimental program requires exacting store conditions for both ions. These systematic error concerns presented new challenges for the Collider, including frequent reconfiguration of the Collider for the different ion species, and maintaining level amounts of instantaneous and integrated luminosity between two species. Moreover, making beams of Zr-96 and Ru-96 is challenging since the natural abundances of these isotopes are low. Creating viable enriched source material for Zr-96 required assistance processing from RIKEN, while Ru-96 was provided by a new enrichment facility under commissioning at Oak Ridge National Laboratory.
	Slides MOZPLS2 [4.758 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZPLS2
About •	paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOZZPLM2	A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution	rfq, linac, background, electron	37
	Y. Sue, K. Inami Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, R. Kitamura, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan K. Ishida RIKEN Nishina Center, Wako, Japan Y. Kondo JAEA, Ibaraki-ken, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Takeuchi Kyoto ICR, Uji, Kyoto, Japan T. Ushizawa Sokendai, Ibaraki, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan M. Yotsuzuka Nagoya University, Nagoya, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster.
	Slides MOZZPLM2 [2.618 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOZZPLM3	Commissioning and First Results of the Fermilab Muon Campus	positron, target, proton, MMI	41
	D. Stratakis, B.E. Drendel, J.P. Morgan, M.J. Syphers Fermilab, Batavia, Illinois, USA N.S. Froemming CENPA, Seattle, Washington, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	In the following years, the Fermilab Muon Campus will deliver highly polarized muon beams to the Muon g-2 Experiment. The Muon Campus contains a target section wherein secondaries are produced, the delivery ring which separates the muons from the rest of the beam and a sequence of beamlines that transports them to the Muon g-2 storage ring. Here, we report the first results of beam measurements at the Muon Campus with emphasis on the key achievements that have contributed to the successful beam delivery to the Muon g-2 Experiment. These achievements include the production of an intense secondary beam from the target, it’s transport over 2 km, the successful monitoring of muons from the available diagnostics and the development of techniques for measuring the transverse optics. We also present detailed comparisons between experimental data and simulation and discuss the similarities and differences observed.
	Slides MOZZPLM3 [2.846 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM3
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPGW011	Field-map and Beam Transport Calculations of the Magnetic Separator at ALTO Facility at Orsay	dipole, ISOL, ion-source, target	86
	L. Perrot, R. Ollier IPN, Orsay, France
	The Institute of Nuclear Physics at Orsay (IPN-Orsay) has always been a major player in building accelerators for nuclear physics. The ALTO facility is powered by a 50 MeV/10μA linear electron accelerator dedicated to the production of radioactive beams. The production mode is based on the photo-fission process of a thick UCx target heated up to 2000°C and using the ISOL technique. For the ionization of the released fission fragments, three ion source types can be coupled to the target: Febiad ion source, surface ion source, and laser ion source. The facility can deliver the radioactive ions beams to six different experimental set-ups. The mono-charged RIB exiting from the source must be separated using a magnetic dipole in order to select a nucleus before its transmission through electrostatic devices up to the experimental set-ups. This paper is focus on the separator which was build and exploited with success since 40 years. We propose to revisit this dipole with a precise field-map calculation and particles transport simulations. These results will be use as a first brick of the understanding and reliability of the transmission along the RIB lines at the ALTO facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW011
About •	paper received ※ 19 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW022	Achromatic Isochronous Mode of the ESR at GSI	optics, sextupole, detector, emittance	124
	S.A. Litvinov, M. Steck GSI, Darmstadt, Germany
	The isochronous optics of the ESR is a unique ion-optical setting in which the ring is operated as a Time-of-Flight Mass-Spectrometer and is used for direct mass measurements of short-lived exotic nuclei. The present isochronous optics had been performed only making a negative dispersion in the straight sections of the ESR of about -7 m. This negative dispersion makes the injection into the ESR very complicated and strict the transmission of the ions in the ring. Moreover, the non-achromatism of the ESR brings a supplementary uncorrectable first-order transverse contribution to the revolution time. In order to make the ESR achromatic, to improve injection and the isochronicity a new achromatic isochronous optics has been calculated and will be presented here in details.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW022
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW024	Measurements of the GSI Transfer Beam Lines Ion Optics	quadrupole, extraction, emittance, storage-ring	131
	M. Sapinski, O. Geithner, S. Reimann, P. Schütt, M. Vossberg, B. Walasek-Höhne GSI, Darmstadt, Germany C. Heßler CERN, Meyrin, Switzerland
	GSI High Energy Beam Transfer lines (HEST) link the SIS18 synchrotron with two storage rings (Experimental Storage Ring and Cryring) and six experimental caves. The recent upgrades to HEST beam instrumentation enables precise measurements of beam properties along the lines and allow for faster and more precise beams setup on targets. Preliminary results of some of the measurements performed during runs in 2018 and 2019 are presented here. The focus is on response matrix measurements and quadrupole scans performed on HADES beam line. The errors and future improvements are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW024
About •	paper received ※ 15 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW027	Design Considerations for Permenant Magnetic Quadrupole Triplet for Matching Into Laser Driven Wake Field Acceleration Experiment at SINBAD	laser, plasma, electron, acceleration	143
	S. Yamin, R.W. Aßmann, U. Dorda, F. Lemery, B. Marchetti, E. Panofski, P.A. Walker DESY, Hamburg, Germany
	SINBAD (Short and INnovative Bunches and Accelerators at DESY) facility aims to produce ultrashort bunches (sub-fs) at ~100 MeV, suitable for injection into novel accelerators e.g. dielectric Laser acceleration (DLA) and Laser Driven Wakefield acceleration (LWFA). The LWFA experiment demands β functions to be of the order of 1 mm to reduce energy spreads and emittance growth from nonlinearities. Matching such a space charge dominated beam to such constraints with conventional electromagnets is challenging. A Permanent Magnetic Quadrupole (PMQ) triplet is one promising focusing strategy. In this paper, we investigate the performance of a PMQ triplet to fit the requirements of the electron beam properties in a plasma cell and discuss the realizable phase spaces for the LWFA experiment planned at SINBAD.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW027
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW047	Analysis and Simulation of the "After-Pulse" RF Breakdown	cavity, simulation, timing, GUI	196
	X. Lin, H.B. Chen, Z.N. Liu, J. Shi, H. Zha TUB, Beijing, People’s Republic of China X.W. Wu CERN, Meyrin, Switzerland
	During the high power experiment of a single-cell standing-wave accelerating structure, it was observed that many RF breakdowns happen when the field inside cavity is decaying after the input rf pulse is off. The distribution of breakdown timing shows a peak at the moment of RF power switches off. A series of simulation was performed to study the after-pulse breakdown effect in such a standing-wave structure. A method of calculating poynting vector over time is proposed in this article to study the modified poynting vector at critical points in the cavity. Field simulation and thermal simulation were also carried out to analyse possible reasons for the after-pulse breakdown effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW047
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPGW067	On Coordinate Systems in Beam Dynamics	simulation, GUI, acceleration, FEL	243
	E. Laface ESS, Lund, Sweden
	Any description of the beam dynamics calculation and simulation relies on the proper choice of a coordinate system in order to minimize the computational complexity and to apply different level of approximations in the calculations. This need generates a large number of reference systems, especially to describe the longitudinal dynamics of a particle beam like(z, z′),(t,∆P/P),(z, φ), etc. In this paper we summarize the rules to change coordinates systems, which system is canonical and how the Hamiltonian of the beam transforms according to the chosen coordinate system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW067
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW073	Beam Manipulation Using Self-Induced Fields at the SwissFEL Injector	FEL, simulation, electron, wakefield	266
	S. Bettoni, P. Craievich, E. Ferrari, R. Ganter, F. Marcellini, E. Prat, S. Reiche PSI, Villigen PSI, Switzerland A.A. Lutman SLAC, Menlo Park, California, USA G. Penco Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	In the past years wakefield sources have been used to manipulate electron beams in accelerators. We recently installed corrugated structures for a total length of 2~m at the SwissFEL injector to test novel schemes for beam manipulations. We present simulations and early experimental results. We compare the model predictions with the measured data for the bunch energy losses and the kick factor, and show early results for the longitudinal phase space linearization and the production of current spikes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW073
About •	paper received ※ 09 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW105	Preliminary Lattice Studies for the Single-Invariant Optics Experiment at the University of Maryland	lattice, octupole, optics, resonance	367
	L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, I. Haber, D.B. Matthew UMD, College Park, Maryland, USA K.J. Ruisard ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported through DOE-HEP Award DESC0010301 and NSF Award PHY1414681. A novel approach to transverse resonance suppression in next generation high-intensity accelerators is the use of nonlinear optical elements to induce large tune spreads which result in reduced responses to resonance driving perturbations. In order to test this theory, we have built and characterized an octupole channel insert for use in the University of Maryland Electron Ring (UMER). This paper presents experimental lattice studies using a low space-charge intensity beam at an energy of 10keV with a beam current of ~150uA, tune depression < 0.005, and unnormalized RMS emittance of 4.3 mm-mr. We apply beam based measurement techniques in order to evaluate the quality of our single-invariant lattice and better understand the nonlinearities created by the octupole channel. V. Danilov and S. Nagaitsev, Nonlinear accelerator lattices with one and two analytic invariants, PRSTAB, 13, 084002, 2010.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW105
About •	paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW113	Experimental Demonstration of the Henon-Heiles Quasi-Integrable System at IOTA	octupole, lattice, optics, alignment	386
	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 National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy. The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report the first results of experimental investigation of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread and dynamic aperture preservation. Resilience to perturbations and imperfections in the lattice is explored. We conclude by outlining future research plans and discussing applicability to future high intensity accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW113
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPGW125	Lossless Crossing of 1/2 Resonance Stopband by Synchrotron Oscillations	resonance, lattice, betatron, storage-ring	410
	G.M. Wang, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk BNL, Upton, Long Island, New York, USA
	Funding: DOE under contract No.DE-AC02- 98CH10886 Modern high performance circular accelerators require sophisticated corrections of nonlinear lattices. The beam betatron tune footprint may cross many resonances, reducing dynamic aperture and causing particle loss. However, if particles cross a resonance reasonably fast, the beam deterioration may be minimized. In this paper, we present the experiments with the beam passing through a half-integer resonance stopband via chromatic tune modulation by exciting synchrotron oscillations. This is the first time that beam dynamics have been kept under precise control while the beam crosses a half-integer resonance. Our results convincingly demonstrate that particles can cross the half-integer resonance without being lost if the passage is reasonably fast and the resonance stopband is sufficiently narrow.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW125
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP019	High Luminosity LHC Optics and Layout HLLHCV1.4	optics, luminosity, operation, cavity	468
	R. De Maria, R. Bruce, D. Gamba, M. Giovannozzi, F. Plassard CERN, Geneva, Switzerland
	The goal of the High Luminosity Project is the upgrade of the LHC to deliver an integrated luminosity of at least 250 \rm fb^-1 per year in each of the two high-luminosity, general-purpose detectors ATLAS and CMS. This article presents the latest layout design and the corresponding optics features, which comprise optimisation of the orbit corrector and crab cavity systems, and new estimates of the performance reach thanks to the new concept of fully remote alignment. In addition, the new optics version incorporates improvements required by beam instrumentation, dump system, and collimation system, as well as low-beta solutions for the LHCb experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP019
About •	paper received ※ 17 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP024	Prospects for Future Asymmetric Collisions in the LHC	proton, luminosity, operation, hadron	484
	M.A. Jebramcik, J.M. Jowett CERN, Geneva, Switzerland
	The proton-lead runs of the LHC in 2012, 2013 and 2016 provided luminosity far beyond expectations in a diversity of operating conditions and led to important new results in high-density QCD. This has permitted the scope of the future physics programme to be expanded in a recent review. Besides further high-luminosity p-Pb collisions, lighter nuclei are also under consideration. A short proton-oxygen run, on the model of the 2012 p-Pb run, would be of interest for cosmic-ray physics. Other collision systems like proton-argon or collisions of protons with other noble gases are also discussed. We provide an overview of the operational strategies and potential performance of various asymmetric collision options. Potential performance limits from moving beam-beam encounters at injection and various beam-loss mechanisms are evaluated in the light of our understanding of the LHC to date.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP024
About •	paper received ※ 18 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPMP033	LHC Run 2 Optics Commissioning Experience in View of HL-LHC	optics, luminosity, coupling, simulation	508
	R. Tomás, F.S. Carlier, J.M. Coello de Portugal, J. Dilly, S.D. Fartoukh, E. Fol, D. Gamba, A. Garcia-Tabares, M. Giovannozzi, M. Hofer, E.H. Maclean, L. Malina, T.H.B. Persson, P.K. Skowroński, M. Solfaroli, M.L. Spitznagel, A. Wegscheider, J. Wenninger, D.W. Wolf CERN, Geneva, Switzerland
	LHC Run 2 has achieved a beta lower than a factor 2 below design. This has significantly challenged optics measurement and correction techniques in the linear and non-linear regimes, leading to the development of new approaches. Furthermore, experimenting with a large variety of optics has allowed facing the difficulties of future optics and gaining understanding of the machine imperfections. A summary of these aspects is given in view of their implications for the HL-LHC Project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP033
About •	paper received ※ 07 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP052	Numerical Simulations of the DC Wire Prototypes in LHC for Enhancing the HL-LHC Performances	simulation, luminosity, optics, resonance	566
	A. Poyet Université Grenoble Alpes, Grenoble, France S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, K. Skoufaris, G. Sterbini CERN, Geneva, Switzerland
	For the last 15 years, the compensation of the Beam-Beam Long-Range (BBLR) interaction in colliders using DC wires has been studied. In 2015, in the frame of the HL-LHC project, it has been shown that a compensation of all the Resonance Driving Terms (RDTs) generated by the BBLR interaction is possible using wires with constraints on their transverse and longitudinal positions. In 2017, an experimental campaign has been launched in the present LHC, with wires installed in sub-optimal positions due to integration constraints. The aim of this paper is therefore to apply the formalism developped for HL-LHC to the LHC case and to compare the experimental results to the numerical tracking studies of the compensation using wires.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP052
About •	paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB011	Progress on Muon Ionization Cooling Demonstration with MICE	simulation, emittance, detector, framework	594
	C. Hunt Imperial College of Science and Technology, Department of Physics, London, United Kingdom V.C. Palladino INFN-Napoli, Napoli, Italy C.G. Whyte USTRAT/SUPA, Glasgow, United Kingdom
	Funding: STFC, NSF, DOE, INFN, CHIPP andd more The Muon Ionization Cooling Experiment (MICE) at RAL has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. Further studies are providing now more and deeper insight. Submitted by the chair of our MICE speakers bureau. If accepted, a member of the collaboration will soon be identified to present the contribution and will register immediately after.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB011
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB013	Focusing of High-Brightness Electron Beams with Active-Plasma Lenses	plasma, emittance, focusing, electron	601
	R. Pompili INFN/LNF, Frascati, Italy
	Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB013
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB017	Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment	cavity, linac, DTL, coupling	606
	Y. Nakazawa, H. Iinuma Ibaraki University, Ibaraki, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan R. Kitamura, H.Y. Yasuda University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784. An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB017
About •	paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPRB018	Conceptual Design of Negative-Muon Decelerator for Material Science	cavity, induction, impedance, power-supply	610
	C. Ohmori, M. Otani, K. Shimomura KEK, Tokai, Ibaraki, Japan T. Takayanagi JAEA/J-PARC, Tokai-mura, Japan
	In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB018
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB023	Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam	emittance, rfq, polarization, acceleration	622
	H.Y. Yasuda University of Tokyo, Tokyo, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan N. Kawamura, T. Mibe, M. Otani KEK, Ibaraki, Japan Y. Kondo JAEA/J-PARC, Tokai-mura, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Numbers JP18J22129, JP18H03707. Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB023
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB026	High-Quality Muon Beam Production Based on Superconducting Solenoids	target, proton, polarization, solenoid	630
	Y. Bao, X. Li, Y. Li, Y.P. Song, X. Tong IHEP, Beijing, People’s Republic of China
	Funding: This work is supported by the Science Foundation of The Chinese Academy of Sciences and National Natural Science Foundation of China (No. 11875281) In labs, muon beams are produced by protons hitting targets. The initial phase space of the muon beam is extremely large. In general, two types of muon collection methods have been used in the world. One is to put the muon production target in a superconducting solenoid, and low-energy muons are collected from the back of the target, then transported through a bent solenoid. In this way, a high-intensity muon beam can be collected, but the energy spread is wide and the beam polarization is low. For most muSR applications a surface muon beam with narrow energy bite and high polarization is required. Most muSR facilities are built with collecting magnets by the side of the target, in this way only a small fraction of muons with low emittance are collected and transported downstream. In this work we outline a muon collection method based on superconducting solenoid. Instead of using bent solenoids, a matching section with a dipole magnet is used to select muons with a certain momentum and match to downstream beamliines. A high-quality muon beam can be achieved with a high intensity and polarization. Such a method can be adapted to the MUSIC, Mu2e, and COMET muon beamlines after their dedicate experiments and convert the beamlines into a high quality muSR facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB026
About •	paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB036	Study on Beam-induced heating in injection section of Hefei Light Source	impedance, vacuum, kicker, radiation	652
	D.R. Xu, W. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Ceramic chambers distributed with metal belts on the inner surface are installed in the injection section at Hefei Light Source (HLS). Heating on the ceramics chambers has been observed during machine operation. An air compressor is used to cool these chambers due to concerns of overheating during top-up operation mode. To understand the sources of the heating, a series of experiments are performed with various beam currents and bunch filling patterns. The study shows that the heating is mainly caused by the narrow-band impedances of the ceramic chambers and their adjacent vacuum components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB036
About •	paper received ※ 22 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB043	Two-Beam Operation in DESIREE	pick-up, injection, detector, ion-source	659
	A. Källberg, M. Björkhage, M. Blom, H. Cederquist, P. Reinhed, S. Rosén, H.T. Schmidt, A. Simonsson, H. Zettergren Stockholm University, Stockholm, Sweden
	The current status of DESIREE is described, with special emphasis on the setup for collision experiments with ions in both the two electrostatic rings - negative ions in one ring and positive in the other. By measuring the kinetic energy released in mutual neutralization reactions be-tween the two ions at collision energies close to zero eV in 3D, the population of different reaction channels has been obtained. The different steps necessary to set up the beams to get well controlled experimental properties are described as well as the principles behind our automatic optimization routines, which are extensively used with consistent result.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB043
About •	paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB049	Study of Beam-Gas Interactions at the LHC for the Physics Beyond Colliders Fixed-Target Study	target, proton, collider, simulation	673
	C. Boscolo Meneguolo, R. Bruce, F. Cerutti, M. Ferro-Luzzi, M. Giovannozzi, A. Mereghetti, J. Molson, S. Redaelli CERN, Geneva, Switzerland A. Abramov JAI, Egham, Surrey, United Kingdom
	Among several working groups formed in the framework of Physics Beyond Colliders study, launched at CERN in September 2016, there is one investigating specific fixed-target experiment proposals. Of particular interest is the study of high-density unpolarized or polarized gas target to be installed in the LHCb detector, using storage cells to enhance the target density. This work studies the impact of the interactions of 7 TeV proton beams with such gas targets on the LHC machine in terms of particle losses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB049
About •	paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPRB052	Gamma Factory at CERN: Design of a Proof-of-Principle Experiment	photon, laser, electron, cavity	685
	Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann CERN, Geneva, Switzerland S.E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay JAI, Egham, Surrey, United Kingdom A. Apyan ANSL, Yerevan, Armenia E.G. Bessonov LPI, Moscow, Russia A. Bosco, S.M. Gibson, L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom F. Castelli Università degli Studi di Milano, Milano, Italy F. Castelli, C. Curatolo, L. Serafini INFN-Milano, Milano, Italy K. Kroeger FSU Jena, Jena, Germany A. Martens LAL, Orsay, France V. Petrillo Universita’ degli Studi di Milano, Milano, Italy M. Sapinski, T. Stöhlker GSI, Darmstadt, Germany G. Weber IOQ, Jena, Germany Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052
About •	paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB055	First Partially Stripped Ions in the LHC (208Pb⁸¹⁺)	injection, collimation, factory, operation	689
	M. Schaumann, R. Alemany-Fernández, H. Bartosik, T. Bohl, R. Bruce, G.H. Hemelsoet, S. Hirlaender, J.M. Jowett, V. Kain, M.W. Krasny, J. Molson, G. Papotti, M. Solfaroli Camillocci, H. Timko, J. Wenninger CERN, Geneva, Switzerland
	The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron (208Pb⁸¹⁺) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few 208Pb⁸¹⁺ bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB055
About •	paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB056	THz Radiator Based on Photonic Band Gap Crystal for SwissFEL	electron, photon, GUI, FEL	693
	L. Shi, R. Ischebeck, S. Reiche PSI, Villigen PSI, Switzerland
	Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647. The electromagnetic radiation in 1-20 THz has many unique properties when it interacts with matter due to its non-ionizing excitation in matter. Especially the dynamics of the excited matter can be probed with the help of X-ray pulses at a free electron laser facility, e.g. SwissFEL, to deepen our understanding of a wide range of phenomena. Due to its high research potential, various means of THz generation have been proposed and demonstrated. We investigate preliminarily here its generation based on a relativistic electron bunch and a photonic band gap crystal (PBG) made of dielectric rods. The PBG provides additional degrees of freedom for the THz pulse tuning. Additionally, the unwanted radiation parts can be damped by the structure in order to minimize the deleterious beam dynamics effects. The crystal also promises the integration of generation, filtering and coupling for transport into a single piece.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB056
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB063	Longitudinal Tomography in a Scaling FFA	synchrotron, cavity, proton, injection	719
	D.J. Kelliher, C. Brown, J.-B. Lagrange, S. Machida, C.R. Prior, C.T. Rogers STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom Y. Ishi, Y. Kuriyama, H. Okita, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan S.L. Sheehy JAI, Oxford, United Kingdom
	In a synchrotron the rate of acceleration is limited by the ramp rate of the bending field. There is no such constraint in a Fixed Field alternating gradient Accelerator (FFA), allowing a much higher repetition rate and novel modes of operation such as beam stacking. It is of interest to obtain a picture of the longitudinal phase space from experimental data in order to diagnose the response of the beam to various RF programmes. Longitudinal tomography, already well established in synchrotrons, involves reconstructing the phase space using bunch monitor data obtained for a sufficient number of turns in a synchrotron oscillation. Here we reconstruct the longitudinal phase space using data from the 150 MeV scaling FFA at KURNS, Osaka, Japan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB063
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB065	Enhancing Experimental Prospects With Low Energy Antiprotons	proton, antiproton, detector, cryogenics	727
	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 programme under the Marie SkłodowskaCurie grant agreement No 721559. The Extra Low Energy Antiproton ring (ELENA) is a critical upgrade to the Antiproton Decelerator (AD) at CERN and saw the first beam in 2018. ELENA will significantly enhance the achievable quality of low energy antiproton beams and enable new experiments. To fully exploit the potential of this new facility, advances are required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to fully characterize the beam’s properties, as well as in novel experiments that take advantage of the enhanced beam quality that ELENA can provide. These research areas are in the heart of the pan-European research and training network AVA (Accelerators Validating Antimatter physics) which started in 2017. This contribution presents research results within AVA on the performance of ultra-thin diamond membranes, electron cooling and beam life time studies of low energy ion and antiproton beams, as well as efficient integration and performance optimization of cryogenic detectors in ELENA and associated trap experiments. These results are used to describe the optimum layout of a state-of-the-art low energy antiproton facility and associated experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB065
About •	paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPRB069	Generation of High Power Short Rf Pulses using an X-Band Metallic Power Extractor Driven by High Charge Multi-Bunch Train	pick-up, multipactoring, acceleration, simulation	734
	J.H. Shao, M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA H.B. Chen, M.M. Peng, J. Shi, H. Zha TUB, Beijing, People’s Republic of China C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA J. Seok UNIST, Ulsan, Republic of Korea
	Short pulse two-beam acceleration (TBA) is a structure wakefield acceleration (SWFA) approach aiming to achieve gradient above 250 MV/m using rf pulses less than 20 ns. An X-band 11.7 GHz metallic power extractor has been developed as the power source to test accelerating structures in this extreme regime. The power extractor is designed to be driven by high charge bunches separated by 769.2 ps (9 times the X-band period) on an L-band 1.3 GHz beamline. In the recent experiment, ~280 MW rf pulses with 3 ns flat-top have been measured by a coaxial rf pickup when driven by 8-bunch trains with a total charge of ~500 nC. The power level is ~50% lower than the theoretical prediction and simulation. Experimental investigation suggests that the missing power was mainly caused by the multipacting issue inside the rf pickup, which could be eliminated by a newly-designed directional coupler.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB069
About •	paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB087	Proposal for a High Transformer Ratio CW Dielectric Accelerator	electron, SRF, wakefield, operation	773
	V. Litvinenko Stony Brook University, Stony Brook, USA J.C. Brutus, Y.C. Jing, I. Pinayev, G. Wang BNL, Upton, Long Island, New York, USA M.E. Conde, C.-J. Jing, J.G. Power ANL, Argonne, Illinois, USA A. Kanareykin Euclid Beamlabs LLC, Bolingbrook, USA N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA
	Advanced CW accelerators are one of high priority directions identified by Advanced Accelerator Concepts Research Roadmap Workshop Report . High transformer ratio of beam-driven accelerators is critically important for cost-effective FEL systems. We present a proposed experiment for demonstrating a high transformer ratio CW dielectric accelerator using operational SRF accelerator built for Coherent electron Cooling experiment. This accelerator operates with CW electron beam comprised of 78 kHz train of electron bunches. Electron bunches with controllable longitudinal and charge up to 10 nC per bunch are generated in 1.25 MV SRF photo-electron gun. This bunches are ballistically compressed to duration of 10-to-30 psec and accelerated to 15 MeV in SRF linac. Such bunches would be excellent drivers of high-transformer ratio DWA accelerators. In this paper we present expected performance of proposed CW DWA accelerator. Advanced Accelerator Concepts Research Roadmap Workshop Report, 2016, *V.N. Litvinenko et al., In proc.of FEL’17, Santa Fe, NM, USA, August 20-25, 2017, p. 132
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB087
About •	paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPRB088	Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab	undulator, electron, radiation, photon	777
	I. Lobach University of Chicago, Chicago, Illinois, USA A. Halavanau, Z. Huang, V. Yakimenko SLAC, Menlo Park, California, USA K. Kim ANL, Argonne, Illinois, USA V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA A.Y. Murokh RadiaBeam, Los Angeles, California, USA T.V. Shaftan BNL, Upton, Long Island, New York, USA
	We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab with an InGaAs PIN photodiode and an integrating circuit. Our study was motivated by the previous experiment . We propose a theoretical model for the experimental data from and in our own experiment we attempted to verify the model in an independent and more systematic way. Moreover, these fluctuations are an interesting subject for a study by itself, since they act as a seed for SASE in FELs. We improve the precision of the measurements from * by subtracting the average signal amplitude using a comb filter with a one-turn IOTA delay, and by using a special algorithm for noise subtraction. We obtain a reasonable agreement between our theoretical model and experiment. Along with repeating the experiment from , which was performed at a constant beam current, we also collect data for fluctuations in undulator light at different beam current values. Lastly, in our experiment we were able to see the transition from Poisson statistics to Super-Poisson statistics for undulator light, whereas in only the latter statistics was observed. * M. Teich et al., PRL, vol. 65, no. 27, p. 3393 (1990).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB088
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPRB089	Experimental Study of a Single Electron in a Storage Ring via Undulator Radiation	photon, electron, undulator, radiation	781
	S. Nagaitsev, A.L. Romanov, G. Stancari Fermilab, Batavia, Illinois, USA A. Arodzero, A.Y. Murokh, M. Ruelas RadiaBeam, Santa Monica, California, USA I. Lobach University of Chicago, Chicago, Illinois, USA T.V. Shaftan BNL, Upton, Long Island, New York, USA
	A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB089
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB104	A Parameter Study for Improving the Performance of the Production Target for the Fermilab Muon g-2 Experiment	target, simulation, storage-ring, proton	806
	D. Stratakis Fermilab, Batavia, Illinois, USA
	The target station of the Muon g-2 Experiment is one of the central pieces for the production of secondary pions which eventually will decay to the desired mu-ons. In this paper, we report adjustments made to opti-mize its performance. For instance, in the simulation we vary the size of the primary incoming beam and examine its impact on the downstream production. We then compare this with the actual measured beam size upstream of the target. In addition, we examine the sensitivity in performance with the strength of the lithium lens for pion capture and the distance between lens and target. We compare measured data with simu-lation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB104
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB105	Measurement and Analysis of Beam Phase-space Distributions for the Fermilab Muon Campus accelerator complex	quadrupole, emittance, framework, simulation	810
	A. Ramirez University of Houston, Houston, Texas, USA D. Stratakis Fermilab, Batavia, Illinois, USA
	The Muon g-2 experiment at Fermilab is tasked with measuring the muon’s anomalous magnetic moment with high precision. Since the experiment requires large amounts of muons, it is imperative to systematically study the behavior of the beam along the transport line. Unfortunately, the available diagnostics only provide beam information in X-Y space. For a complete evaluation, information of the phase-space is required. This paper demonstrates a technique to measure the beam phase-space distribution by using a set of beam profiles. First, we establish the theoretical framework that describes the principle of the technique. Next, we apply the technique at four different locations along the accelerator delivery line. Finally, we compare our findings to predictions from tracking simulations. Our results indicate that the beam phase-space volume is conserved, along the beam delivery line, suggesting minimal loses and linear transport as expected by design. Compared to the simulations, there is good agreement in both horizontal and vertical plane with the former being at the 4% level while the latter being in the 15% level. Our proposed technique is expected to provide a promising approach for optimizing injection and thereby improving the performance of the Muon g-2 Experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB105
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS005	Status of the SPIRAL2 Project	linac, neutron, MMI, proton	844
	P. Dolegieviez, R. Ferdinand, X. Ledoux, H. Savajols, F. Varenne GANIL, Caen, France
	The SPIRAL2 facility at GANIL will use a high-power p, d and heavy-ion superconducting linac for a wide range of applications including RIB production using both ISOL and in-flight techniques. The SPIRAL2 phase 1 deals with the high-power superconducting linac with two experimental areas called ’Neutrons for Science’ (NFS) and ’Super Separator Spectrometer’ (S3). The low energy experimental hall DESIR, under construction, will further increase the possibility for physics experiments. All the linac is installed, the commissioning of the injec-tor part (two sources and the A/Q = 3 RFQ) and two cool down of the entire superconducting linac have been suc-cessfully done. We are now in the linac beam commis-sioning phase. The project scope and parameters, the constraints linked to the safety rules, the accelerator, NFS, S3 and DESIR status and the planning will be pre-sented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS005
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS014	The Experimental Area at the ARES LINAC	laser, electron, linac, acceleration	867
	F. Burkart, R.W. Aßmann, U. Dorda, J. Hauser, S. Lederer, F. Lemery, B. Marchetti, F. Mayet, E. Panofski, P. Wiesener DESY, Hamburg, Germany M. Trunk University of Hamburg, Hamburg, Germany
	The ARES (Accelerator Research Experiment at SINBAD) linac at the accelerator R&D facility SINBAD (Short innovative bunches and accelerators at DESY) will drive multiple independent experiments including the acceleration of ultrashort electron bunches. In addition the linac will host an experimental area, open for transnational access, to study advanced high gradient, laser driven, acceleration concepts, like the ones studied within the ACHIP (accelerator on a chip) project. The area will be operational mid-2019. This paper will report on the current status of the experimental area, including hardware parameters, beam optics, achievable beam parameters, design of the experimental chamber and commissioning plans. The modification plans for a micro-bunching experiment in the frame of the ACHIP experiment and future upgrade plans will be shown and discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS014
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS026	Status Report of the SINBAD-ARES RF Photoinjector and LINAC Commissioning	gun, linac, electron, laser	906
	E. Panofski, R.W. Aßmann, F. Burkart, U. Dorda, K. Flöttmann, M. Hüning, B. Marchetti, D. Marx, F. Mayet, P.A. Walker, S. Yamin DESY, Hamburg, Germany
	The accelerator R&D facility SINBAD (Short innovative bunches and accelerators at DESY) will drive multiple independent experiments including the acceleration of ultrashort electron bunches and the test of advanced high gradient acceleration concepts. The SINBAD-ARES (Accelerator Research Experiment at SINBAD) setup hosts a normal conducting RF photoinjector generating a low charge electron beam that is afterwards accelerated to 100 MeV by an S-band linac section. The linac as well as a magnetic chicane allow the production of ultrashort pulses with an excellent arrival-time stability. The high brightness beam has then the potential to serve as a test beam for next generation compact acceleration schemes. The setup of the SINBAD-ARES facility will proceed in stages. We report on the current status of the ARES RF gun and linac commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS026
About •	paper received ※ 22 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS028	Search for Electric Dipole Moments at Cosy in Jülich - Spin-Tracking Simulations Using Bmad	simulation, dipole, storage-ring, alignment	914
	V. Poncza, A. Lehrach FZJ, Jülich, Germany A. Lehrach, V. Poncza RWTH, Aachen, Germany
	The observed matter-antimatter asymmetry in the universe cannot be explained by the Standard Model (SM) of particle physics. In order to resolve the matter dominance an additional CP violating phenomenon is needed. A candidate for physics beyond the SM is a non-vanishing Electric Dipole Moment (EDM) of subatomic particles. Since permanent EDMs violate parity and time reversal symmetries, they are also CP violating if the CPT -theorem is assumed. The JEDI (Jülich Electric Dipole moment Investigations) collaboration in Jülich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. In order to analyse the data and to disentangle the EDM signal from systematic effects spin tracking simulations are needed. Therefore a model of COSY was implemented using the software library Bmad. It includes the measured magnet misalignments of the latest survey and a simplified description of the RF-Wien Filter device that is used for the EDM measurement. The model was successfully benchmarked using analytical predictions of the spin behavior. A crucial point regarding the data analysis is the knowledge of the orientation of the invariant spin axis with vanishing EDM at the position of the RF-Wien Filter. Especially its radial component is unknown and spin tracking simulations can be used to determine this missing number. Tracking results as well as the algorithm to find the invariant spin axis will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS028
About •	paper received ※ 25 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS046	Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC	rfq, linac, operation, MMI	960
	Y. Kondo, K. Hirano, T. Ito, N. Kikuzawa, R. Kitamura, T. Morishita, H. Oguri, K. Ohkoshi, S. Shinozaki, K. Shinto JAEA/J-PARC, Tokai-mura, Japan Z. Fang, Y. Fukui, K. Futatsukawa, K. Ikegami, T. Miyao, K. Nanmo, M. Otani, T. Shibata KEK, Ibaraki, Japan T. Hori, Y. Nemoto, Y. Sato Nippon Advanced Technology Co., Ltd., Tokai, Japan T. Ishiyama, Y. Sawabe Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan Y. Ito Total Saport System Corp., Naka-gun, Ibaraki, Japan Y. Kato Total Support Systems Corporation, Tokai-mura, Naka-gun, Ibaraki, Japan F. Kobayashi ULVAC Human Relations, Ltd., Kanagawa, Japan D. Takahashi, R. Tasaki KIS, Ibaraki, Japan
	We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS046
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS052	Simulation of Electric and Thermal Behavior of Cryogenic Three-cell Copper Accelerating Cavity for High Gradient Experiments	cavity, simulation, cryogenics, coupling	980
	T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, Y. Takahashi LEBRA, Funabashi, Japan
	A C-band three-cell pi-mode accelerating cavity made of high purity copper is under design for use in ultra-high accelerating gradient experiments at a cavity temperature of 20 K. The basic configuration, consisting of mode converter, short circular waveguide and cells with round periphery, is the same as that which was previously employed in the cold model for a 2.6-cell photocathode electron gun cavity. Though the 0.6-cell part in the previous model is replaced with a full cell having a beam duct, the overall electric property of the cavity will not change significantly. The RF input coupling coefficient is adjusted to around 10 at 20 K, which is expected to be lowered significantly due to the increase in the surface resistance by the rapid temperature rise during a high power RF input. The results of the simulations on the electric field and the temperature rise along the cavity surface during the RF pulse are discussed in the report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS052
About •	paper received ※ 13 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPTS054	Status of the CLEAR Electron Beam User Facility at CERN	electron, radiation, plasma, operation	983
	K.N. Sjobak, E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek CERN, Geneva, Switzerland A. Lyapin UCL, London, United Kingdom
	The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS054
About •	paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS075	Design and Experiment of a Window-Type CW Deuteron RFQ	rfq, cavity, operation, Windows	1021
	K. Zhu, M.J. Easton, P.P. Gan, S.L. Gao, H.P. Li, S. Liu, Y.R. Lu, Q.Y. Tan, L. Tao, Z. Wang PKU, Beijing, People’s Republic of China W.P. Dou, Y. He, C. Wang, Q. Wu, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	A deutron CW RFQ was designed and fabricated in Peking University. It will accelerate 50mA CW deutron beam from 50keV to 1MeV at 162.5MHz. The novel structure of four-vane with window was used to seperate the dipole mode from the working mode. The field tuning of this RFQ was different from conventional four vane RFQ because that the four quadrants of RFQ cavity were coupled. The discipline of field tuning was studied by simulation and experiment. The beam dynamics of the RFQ was designed by equipartation and matching method, limit current effect was considered at the same time. The final design result of the RFQ was: voltage between electrodes was 60kV, transport efficiency of RFQ is 98%, field unflatness is less than 2% after tuning, the deformation of RFQcavity is less than 80um. Only 47 hours was spent to increase CW power of cavity from 0 to 55kW in high power test and The RFQ can working stable at the design voltage. The preliminary H²⁺ beam exeperiment has been done and 1.78mA CW beam was obtained at exit of RFQ. This paper will introduce the detail of design and experiment of the RFQ.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS075
About •	paper received ※ 22 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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MOPTS080	Status and Installation Plan of RISP RFQ at Project Site	rfq, site, cavity, resonance	1031
	B.-S. Park, I.S. Hong IBS, Daejeon, Republic of Korea
	Funding: Supported by the Rare Isotope Science Project of Institute for Basic Science funded by the Ministry of Science, ICT (MSIP) and the National Research Foundation (NRF) of Korea (2013M7A1A1075764). The Rare Isotope Science Project (RISP) at Institute for Basic Science (IBS) has been developed a Radio Frequency Quadrupole(RFQ), which was fabricated and commissioned at the off-site test facility. An O+7 beam was accelerated from 10keV/u to 516keV/u as a preliminary beam test. For CW and high power operation, RF conditioning test was also conducted. The RISP RFQ is 5 meters long, 1 meter in diameter and weighs about 16 tons. It was disassembled and transported to the project site, Sin-dong, for installation as the injector system. The installation commenced in April 2019 and the commissioning of the injector system is expected to begin in early 2020. In this paper, the installation status and plans were summarized.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS080
About •	paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS090	Beam-Based Measurement of the Skew-Sextupolar Component of the Radio Frequency Field of a HL-LHC-Type Crab-Cavity	cavity, betatron, sextupole, damping	1066
	M. Carlà, A. Alekou, H. Bartosik, L.R. Carver CERN, Geneva, Switzerland
	Two High Luminosity Large Hadron Collider (LHC) type crab-cavities have been installed in the CERN SPS for testing purposes. An attempt to characterize the skew-sextupolar component of the radio frequency field of the crab-cavity (a3) has been carried out by means of beam-based techniques using turn-by-turn monitoring of the betatron motion. The skew nature of a3 couples the horizontal and vertical betatron motions through a non-linear term. Therefore by exciting the horizontal betatron motion it was possible to observe a spectral line in the vertical beam motion driven by the non-linear coupling at the characteristic frequency 2Qx. A measurement of the magnitude of a3 was thus obtained by characterizing amplitude and phase of such line. The results of the measurements are discussed here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS090
About •	paper received ※ 06 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS091	Mechanical Robustness of HL-LHC Collimator Designs	site, proton, interface, radiation	1070
	F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis CERN, Meyrin, Switzerland
	Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project. Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS092	Numerical and Experimental Evaluation of the DQW Crab Cavity Cryomodule Thermal Budget	cryomodule, cavity, HOM, radiation	1074
	F. Carra, K. Brodzinski, E. Cano-Pleite, O. Capatina CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project One of the key devices of the HL-LHC project are SRF Crab Cavities. A cryomodule with two Double Quarter Wave (DQW) crab cavities has been fabricated at CERN in 2017 and successfully tested with beam in the Super Proton Synchrotron (SPS) in 2018. The aim of the present study is to present and compare the estimation of the thermal budget for the different components of the cryomodule, performed with numerical and semi-analytical methods, with the experimental measurements carried out on the cryomodule after installation in the SPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS092
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUXXPLS2	Negative Muonium Ion Production With a C12A7 Electride Film	target, positron, acceleration, electron	1175
	M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, K. Shimomura, T. Yamazaki KEK, Tsukuba, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan K. Inami, M. Yotsuzuka Nagoya University, Nagoya, Japan K. Ishida RIKEN Nishina Center, Wako, Japan R. Kitamura, H.Y. Yasuda University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: This work was supported by OSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707. Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H⁻ formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented.
	Slides TUXXPLS2 [2.680 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS2
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUZZPLM3	The EPICS Software Framework Moves from Controls to Physics	EPICS, controls, detector, database	1216
	G.R. White, M.V. Shankar SLAC, Menlo Park, California, USA T.M. Cobb DLS, Oxfordshire, United Kingdom L.R. Dalesio, M.A. Davidsaver Osprey DCS LLC, Ocean City, USA S.M. Hartman, K.-U. Kasemir, M.R. Pearson, K. Vodopivec ORNL, Oak Ridge, Tennessee, USA D.G. Hickin EuXFEL, Schenefeld, Germany A.N. Johnson, M.L. Rivers, G. Shen, S. Veseli ANL, Argonne, Illinois, USA H. Junkes FHI, Berlin, Germany M.G. Konrad, G. Shen FRIB, East Lansing, Michigan, USA T. Korhonen ESS, Lund, Sweden M.R. Kraimer Self Employment, Private address, USA R. Lange ITER Organization, St. Paul lez Durance, France M. Sekoranja Cosylab, Ljubljana, Slovenia K. Shroff BNL, Upton, Long Island, New York, USA D. Zimoch PSI, Villigen PSI, Switzerland
	The Experimental Physics and Industrial Control System (EPICS), is an open-source software framework for high-performance distributed control, and is at the heart of many of the world’s large accelerators and telescopes. Recently, EPICS has undergone a major revision, with the aim of better computing supporting for the next generation of machines and analytical tools. Many new data types, such as matrices, tables, images, and statistical descriptions, plus users’ own data types, now supplement the simple scalar and waveform types of the former EPICS. New computational architectures for scientific computing have been added for high-performance data processing services and pipelining. Python and Java bindings have enabled powerful new user interfaces. The result has been that controls are now being integrated with modelling and simulation, machine learning, enterprise databases, and experiment DAQs. We introduce this new EPICS (version 7) from the perspective of accelerator physics and review early adoption cases in accelerators around the world.
	Slides TUZZPLM3 [4.271 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZZPLM3
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP004	Dynamic Pressure in the LHC - Influence of Ions Induced by Ionization of Residual Gas by Both the Proton Beam and the Electron Cloud	electron, proton, vacuum, ECR	1236
	S. Bilgen, C. Bruni, B. Mercier, G. Sattonnay LAL, Orsay, France V. Baglin CERN, Geneva, Switzerland
	Funding: work supported by FCC project (CERN & LAL-CNRS-IN2P3) Ultra-High Vacuum is an essential requirement to reach design performances in high-energy particle colliders. For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. Studies were performed on the ions, produced by molecular ionization generated by the proton beam and the electron cloud, and stimulating molecular desorption by the surface bombardment. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector (VPS), to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated. THE LHC VACUUM PILOT-SECTOR PROJECT B. Henrist, V. Baglin, G. Bregliozzi, and P. Chiggiato, CERN, Geneva, Switzerland Proceedings of IPAC2014, Dresden, Germany.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP004
About •	paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP007	DYVACS (DYnamic VACuum Simulation) Code: Calculation of Gas Density Profiles in Presence of Electron Cloud	electron, vacuum, proton, photon	1244
	G. Sattonnay, S. Bilgen, B. Mercier LAL, Orsay, France V. Baglin CERN, Meyrin, Switzerland
	The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 (and then PyVASCO) is already used to estimate vacuum stability and density profiles in steady state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds. Therefore, we propose an upgrade of this code by introducing electron cloud maps* to estimate the electron density and the ionization of gas by electrons, leading to an increase of both electron- and ion-induced desorption. Results obtained with the new code (called DYVACS for DYnamic VACuum Simulation) will be compared to pressure measurements in the VPS sector**** of the LHC. * A. Rossi, Tech. Rep., LHC Proj. Note 341 I. Aichinger, et al arXiv:1707.07525 * T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007) **** B. Henrist et al, Proc. IPAC2014, Dresden
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP007
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP020	The Research on the Calibration of Direct-Current Current Transformers	power-supply, collider, factory, data-acquisition	1280
	C. Han, Y. Gao, X.L. Guo, P. Liu IHEP, Beijing, People’s Republic of China
	The measurement accuracy of direct current-current transformer (DCCT) is one of the key factors influencing the output of high-precision direct current power supply. In this paper, a calibration system designed by measuring resistance principle with a high accuracy direct current comparator (DCC) was presented for DCCT whose measurement accuracy is better than 10^-5. The system can achieve high-precision calibration of DCCT within the measurement range of 0-400 A, and the uncertainty of the system calibration is better than 1.1×10-6 in the whole range. The accuracy and linearity of DCCT are tested to verify the accuracy of the whole calibration system, thereby the current accuracy of the magnet power supply can be further improved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP020
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP025	Design of Fast Corrector Magnet Power Supply for HEPS	power-supply, controls, simulation, radiation	1294
	P. Liu, C. Han, F. Long IHEP, Beijing, People’s Republic of China
	High energy photon source is a fourth-generation synchrotron radiation light source with energy of 6Gev and ultra-low emittance (<0.1nm’rad). The ultra-low beam emittance requires high beam stability. Therefore, we develop a fast correction power supply with high bandwidth and low current ripple to improve the performance of the fast close orbit correction sys-tem to prove the high beam stability. The power supply adopts FPGA for full-digital control and use high speed ADC with temperature control. The power sup-ply has a small signal-bandwidth of 10 kHz and output current ripple lower than 20ppm. In this paper, we will describe the hardware design and software control methods and the test results will be demonstrated
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP025
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP029	Establishing a Laser Treatment to Suppress the Secondary Electron Emission	laser, electron, synchrotron, focusing	1303
	Y.G. Wang, X.Q. Ge, X.T. Pei, S.W. Wang, Y. Wang, B. Zhang, B.L. Zhu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Laser treatment has a significant inluent on suppressing the secondary electron emission(SEE). The new synchrotron radiation light source, the Hefei Advanced Light Source(HALS) has a strict requirement on the SEE. In this paper, we used a 355nm laser to process copper sample. After the laser treatment, the secondary electron yield(SEY) reduced from 2.05 to 0.86. We used the scanning electron microscope(SEM) to analysis the surface of sample after the laser treatment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP029
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP031	Research on Secondary Electron Emission Characteristics of Diamond-like Carbon Thin Films	electron, vacuum, laser, gun	1306
	Y.X. Zhang, X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, B.L. Zhu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In modern particle accelerators, the build-up of electron cloud is a main limiting factor for the achievement of high-quality beam. Among the techniques to mitigate it, coating the internal walls of the beam pipes with a thin film which has a low secondary electron yield (SEY) is considered to be one of the most effective means. From several earlier studies, it was found that diamond-like carbon (DLC) thin films are potential coatings. This paper is mainly about the research on secondary electron emission characteristics of DLC thin films. The secondary electron emission (SEE) tests were done at temperature of 298 K and vacuum pressure of 2×10^-9 Torr. Here, we obtained the characteristics of the SEE from DLC film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. The maximum secondary electron yield (SEY), δmax, of the DLC thin films under different primary electron doses were also obtained, respectively.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP031
About •	paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP032	Design of Analog to Digital Converter Scheme for High - Precision Electromagnet Power supply	controls, FEL, hardware, dipole	1309
	M.J. Kim, Choi. Choi POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Han, S.-H. Jeong, Y.G. Jung, H.-S. Kang, D.E. Kim, H.-G. Lee, S.B. Lee, S.J. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea M.S. Kim Dongguk University, Seoul, Republic of Korea
	This paper deals with the design of an analogue-to-digital converter (ADC) scheme for a highly precise magnet current supply (MPS). The MPSs are requires with stable and precise current specification in range of the ppm. To meet the requirements, the AD circuit is composed of parallel ADCs of low-medium resolution. Digitally, the oversampling and averaging are performed to increase both the effective resolution and the signal to noise ratio (SNR). The implemented AD circuit was improved about 18 dB (32 times oversampling). The MPS applied by the proposed ADC scheme provides more precise control and the stable current within 10 ppm at 200 A. The experiment used a dipole magnet of the PAL-XFEL and its results proved feasibility through precisely measurable DVM3458A (Keysight Co.).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP032
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP036	Results on the FCC-hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kararesults on the Fcc-Hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kara	photon, radiation, vacuum, electron	1323
	L.A. Gonzalez, V. Baglin, I. Bellafont, P. Chiggiato, C. Garion, R. Kersevan CERN, Geneva, Switzerland I. Bellafont, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain S. Casalbuoni, E. Huttel KIT, Eggenstein-Leopoldshafen, Germany
	Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305. In the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of the FCC-hh beam screen (BS) prototype has been carried out with the aim of testing it at room temperature on the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator) light source. The BS prototype was tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power match quite well the one foreseen for the 50+50 TeV FCC-hh proton collider. The BS prototype (2 m in length) was manufactured according to the base line design (BD) of the FCC-hh BS. It implements a saw-tooth profile designed to absorb the SR generated at the bending magnets. Also, a laser-ablated anti-electron cloud surface texturing [2] was applied at the BS inner walls. We present here the results obtained at BESTEX and the comparison of the results obtained during irradiation of the saw-tooth profile at different geometric configurations. This activity has been carried out in the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System").*
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP036
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPMP039	Data-driven Controller Design Using the CERN Power Converter Control Libraries (CCLIBS)	controls, interface, factory, survey	1335
	A. Nicoletti, M. Martino CERN, Geneva, Switzerland
	The data-driven control approach is a control methodology in which a controller is designed without the need of a model. Parametric uncertainties and the associated unmodeled dynamics are therefore irrelevant; the only source of uncertainty comes from the measurement process. The CERN Power Converter Control Libraries (CCLIBS) have been updated to include data-driven H-infinity control methods recently proposed in literature. In particular, a two-step convex optimization algorithm is performed for obtaining the 2-degree-of-freedom controller parameters. The newly implemented tools in CCLIBS can be used both for frequency response measurement of the load and for controller synthesis. A case study is presented where these tools are used for an application in the CERN East Area Renovation Project for which a high-precision 900 A trapezoidal current pulse is required with 450 ms flat-top and 350 ms ramp-up and ramp-down times. The tracking error must remain within ± 100 parts-per-million (ppm) during the flat-top (before the ramp-down phase starts). The magnet considered in the case study is of non-laminated iron type, hence the necessity of data-driven techniques since the dynamics of such a magnet is difficult to be modeled accurately (due to eddy currents losses). The Power Converter used is a SIRIUS 2P (with a current and voltage rating of 400 Arms and 450 V, respectively) whose digital control loop is regulated at a sampling rate of 5 kS/s.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP039
About •	paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP040	Impact of Flux Jumps on High-Precision Powering of Nb₃Sn Superconducting Magnets	simulation, controls, superconducting-magnet, superconductivity	1338
	M. Martino, P. Arpaia, S. Ierardi CERN, Geneva, Switzerland
	Nb₃Sn superconducting magnets represent a technology enabler for future high-energy particle accelerators. A possible impediment, though, comes from flux jumps that, so far, could not be avoided by design unlike for NbTi technology. However, the impact of flux jumps on the powering has not been properly investigated to date. Flux jumps appear during current ramps at relatively low value of current and tend to disappear towards nominal current. They are usually detected as voltage jumps between different magnet coils but they might also produce overall voltage jumps across the magnet electrical terminals. Such jumps might perturb the power converter feedback control loop and therefore potentially jeopardize its precision performance during energy ramps. This work aims at : (i) presenting preliminary experimental test results on some HL-LHC Nb₃Sn model and prototype magnets, and (ii) attempting to build a simplified electrical model of the flux jumps (with focus only at its interaction with the power converter feedback control loop). Such work is a starting point for outlining possible power converters control strategies able to minimize flux jumps impact on high-precision powering of Nb₃Sn superconducting magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP040
About •	paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP041	Preliminary Design of RF-Shielded Bellows	wakefield, interface, vacuum, shielding	1341
	Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang NSRRC, Hsinchu, Taiwan
	A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041
About •	paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP044	Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems	vacuum, impedance, photon, emittance	1347
	G.Y. Hsiung NSRRC, Hsinchu, Taiwan
	Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW019	Progress of the BESSY VSR Cold String Development and Testing	cavity, GUI, simulation, vacuum	1434
	H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Tannert, A.V. Vélez, D. Wolk, N. Wunderer HZB, Berlin, Germany J. Guo, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW019
About •	paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW024	Pulse Shaping Methods for Laser-Induced Generation of THz Radiation at the Delta Storage Ring	laser, radiation, electron, storage-ring	1453
	C. Mai, B. Büsing, A. Glaßl, S. Khan, D. Krieg, A. Meyer auf der Heide DELTA, Dortmund, Germany
	At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches to give rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW024
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPGW028	Low Energy Beam Transport System for MESA	emittance, cavity, laser, solenoid	1461
	C. Matejcek, K. Aulenbacher, S. Friederich IKP, Mainz, Germany
	An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. The present setup includes the chopper- and bunching system. The devices are of most importance in order to achieve sufficient bunch compression particularely at higher bunch charges and currents. With the circular deflecting cavity of the chopper system it is possible to measure the longitudinal dimension of the bunches upstream of the buncher whereas downstream the longitudinal size will be measured by Smith Purcell radiation. Based on experimental results obtained from this setup we will discuss the beam parameter and compare them with simulations of the beamline.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW028
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW038	Study on Coherent THz Radiation Using Tilt Control of Electron Beam	electron, radiation, solenoid, target	1489
	Y. Tadenuma, M. Brameld, T. Murakami, K. Sakaue, M. Washio Waseda University, Tokyo, Japan
	Funding: This work was supported by a research granted from JSPS KAKENHI 17H02821. The terahertz wave is located in the intermediate frequency band between radio waves and light waves, and researches on the light sources such as terahertz quantum cascade laser and femtosecond laser based THz sources are being conducted. As a new terahertz light source, we are studying coherent Cherenkov radiation by using the tilt control of electron beam and irradiating the target medium. Since the radiation intensity of Cherenkov radiation depends on the target medium, comparison of three kinds of medium with different refractive index and density, and optimization of the target shape were performed. In addition, we are going to try quasi monochromatization of radiation by using multi slit to control the form factor of the electron beam. In this presentation, we will report the experimental results of target optimization and quasi monochromatization and the future prospects. S. S. Dhillon, et al., The 2017 terahertz science and technology roadmap, J. Phys. D: Appl. Phys., 50 (2017) 043001.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW038
About •	paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW094	First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization	quadrupole, storage-ring, operation, emittance	1631
	S.C. Leemann, Ph. Amstutz, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini LBNL, Berkeley, USA
	Funding: This research is funded by US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231. The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW094
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB001	Nanosecond Pulsing for Tandem Accelerator	controls, bunching, linac, injection	1673
	P. Linardakis, N.R. Lobanov, D.C. Tempra Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
	Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism A pulsed system capable of delivering up to a few microampere bursts of ions with mass range M=1 - 100 amu with a duration of approximately 1 ns is described. The system consists of a negative ion source, three frequency harmonic buncher - which uses the entire tandem electrostatic accelerator as a drift path to produce bunched ion bursts at the targets or linac entry - and high energy choppers. The buncher consists of a single acceleration gap with aligned retractable grids.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB001
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB004	Magnetic Measurements of Insertion Devices Using the Vibrating Wire Technique	vacuum, simulation, insertion-device, hardware	1683
	C.K. Baribeau, D. Bertwistle, E.J. Ericson, J.T. Gilbert, T.M. Pedersen CLS, Saskatoon, Saskatchewan, Canada
	The commissioning of new in-vacuum insertion devices (ID) at the Canadian Light Source has motivated the assembly and development of a vibrating wire system. The advantage of the technique is that it is a sensitive magnetic measurement instrument at relatively low cost. Moreover, most hall probe systems require transverse access, which is often not available for in-vacuum or Delta-like devices. It is comparatively simple to string a taut wire through the gap of an in-vacuum ID. We describe the experimental challenges in mapping the field of an 80 mm period in-vacuum wiggler, IVW80, using the vibrating wire technique, and compare results against simulation and data obtained from Hall probe measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB004

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MOYPLM1

Challenges to Higher Beam Power in J-PARC: Achieved Performance and Future Prospects

operation, resonance, extraction, proton

6

S. Igarashi
KEK, Ibaraki, Japan

J-PARC is a world leading intensity frontier accelerator facility, consisting of a 400-MeV H⁻ linac, a 3-GeV Rapid Cycling Synchrotron (RCS) and a 30-GeV slow cycling Main Ring synchrotron (MR). The RCS delivered a 500 kW beam (4.2·10¹³ particles per pulse (ppp)) to the Material and Life science experimental Facility (MLF) in April of 2018, The design power of 1 MW will be delivered in the next few years. Construction of a second target station (2TS) of the MLF with beam power upgraded to 1.5 MW is now under discussion. The MR delivers proton beam to a long-baseline neutrino oscillation experiment, T2K, by fast extraction (FX) and to the hadron experimental facility by slow extraction (SX). For the FX, the maximum beam power is 475 kW and 2.5·10¹⁴ ppp, the world highest ppp in synchrotrons, and for the SX 51 kW and 5.5·10¹³ ppp with an extremely high extraction efficiency of 99.5 %. To achieve 1.3 MW beam power for the neutrino experiment, upgrades to allow operation with a higher repetition rate are planned. The talk will review recent progress of J-PARC facility by highlighting technical challenges toward higher beam power together with future prospects.

Slides MOYPLM1 [9.193 MB]

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MOZPLS2

Ion Collider Precision Measurements With Different Species

target, operation, electron, collider

28

G.J. Marr, E.N. Beebe, I. Blackler, W. Christie, K.A. Drees, P.S. Dyer, A.V. Fedotov, W. Fischer, C.J. Gardner, H. Huang, T. Kanesue, N.A. Kling, V. Litvinenko, C. Liu, Y. Luo, D. Maffei, B. Martin, A. Marusic, K. Mernick, M.G. Minty, C. Naylor, M. Okamura, I. Pinayev, G. Robert-Demolaize, T. Roser, P. Sampson, V. Schoefer, T.C. Shrey, D. Steski, P. Thieberger, J.E. Tuozzolo, K. Zeno, I.Y. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Precedent to electron cooling commissioning and collisions of Gold at various energies at RHIC in 2018, the STAR experiment desired an exploration of the chiral magnetic effect in the quark gluon plasma (QGP) with an isobar run, utilizing Ruthenium and Zirconium. Colliding Zr-96 with Zr-96 and Ru-96 with Ru-96 create the same QGP but in a different magnetic field due to the different charges of the Zr (Z=40) and Ru (Z=44) ions. Since the charge difference is only 10%, the experimental program requires exacting store conditions for both ions. These systematic error concerns presented new challenges for the Collider, including frequent reconfiguration of the Collider for the different ion species, and maintaining level amounts of instantaneous and integrated luminosity between two species. Moreover, making beams of Zr-96 and Ru-96 is challenging since the natural abundances of these isotopes are low. Creating viable enriched source material for Zr-96 required assistance processing from RIKEN, while Ru-96 was provided by a new enrichment facility under commissioning at Oak Ridge National Laboratory.

Slides MOZPLS2 [4.758 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZPLS2

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paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOZZPLM2

A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution

rfq, linac, background, electron

37

Y. Sue, K. Inami
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, R. Kitamura, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Takeuchi
Kyoto ICR, Uji, Kyoto, Japan
T. Ushizawa
Sokendai, Ibaraki, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan
M. Yotsuzuka
Nagoya University, Nagoya, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226.
J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster.

Slides MOZZPLM2 [2.618 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2

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MOZZPLM3

Commissioning and First Results of the Fermilab Muon Campus

positron, target, proton, MMI

41

D. Stratakis, B.E. Drendel, J.P. Morgan, M.J. Syphers
Fermilab, Batavia, Illinois, USA
N.S. Froemming
CENPA, Seattle, Washington, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

In the following years, the Fermilab Muon Campus will deliver highly polarized muon beams to the Muon g-2 Experiment. The Muon Campus contains a target section wherein secondaries are produced, the delivery ring which separates the muons from the rest of the beam and a sequence of beamlines that transports them to the Muon g-2 storage ring. Here, we report the first results of beam measurements at the Muon Campus with emphasis on the key achievements that have contributed to the successful beam delivery to the Muon g-2 Experiment. These achievements include the production of an intense secondary beam from the target, it’s transport over 2 km, the successful monitoring of muons from the available diagnostics and the development of techniques for measuring the transverse optics. We also present detailed comparisons between experimental data and simulation and discuss the similarities and differences observed.

Slides MOZZPLM3 [2.846 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM3

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

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MOPGW011

Field-map and Beam Transport Calculations of the Magnetic Separator at ALTO Facility at Orsay

dipole, ISOL, ion-source, target

86

L. Perrot, R. Ollier
IPN, Orsay, France

The Institute of Nuclear Physics at Orsay (IPN-Orsay) has always been a major player in building accelerators for nuclear physics. The ALTO facility is powered by a 50 MeV/10μA linear electron accelerator dedicated to the production of radioactive beams. The production mode is based on the photo-fission process of a thick UCx target heated up to 2000°C and using the ISOL technique. For the ionization of the released fission fragments, three ion source types can be coupled to the target: Febiad ion source, surface ion source, and laser ion source. The facility can deliver the radioactive ions beams to six different experimental set-ups. The mono-charged RIB exiting from the source must be separated using a magnetic dipole in order to select a nucleus before its transmission through electrostatic devices up to the experimental set-ups. This paper is focus on the separator which was build and exploited with success since 40 years. We propose to revisit this dipole with a precise field-map calculation and particles transport simulations. These results will be use as a first brick of the understanding and reliability of the transmission along the RIB lines at the ALTO facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW011

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paper received ※ 19 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPGW022

Achromatic Isochronous Mode of the ESR at GSI

optics, sextupole, detector, emittance

124

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

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

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

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MOPGW024

Measurements of the GSI Transfer Beam Lines Ion Optics

quadrupole, extraction, emittance, storage-ring

131

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

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

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW024

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

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MOPGW027

Design Considerations for Permenant Magnetic Quadrupole Triplet for Matching Into Laser Driven Wake Field Acceleration Experiment at SINBAD

laser, plasma, electron, acceleration

143

S. Yamin, R.W. Aßmann, U. Dorda, F. Lemery, B. Marchetti, E. Panofski, P.A. Walker
DESY, Hamburg, Germany

SINBAD (Short and INnovative Bunches and Accelerators at DESY) facility aims to produce ultrashort bunches (sub-fs) at ~100 MeV, suitable for injection into novel accelerators e.g. dielectric Laser acceleration (DLA) and Laser Driven Wakefield acceleration (LWFA). The LWFA experiment demands β functions to be of the order of 1 mm to reduce energy spreads and emittance growth from nonlinearities. Matching such a space charge dominated beam to such constraints with conventional electromagnets is challenging. A Permanent Magnetic Quadrupole (PMQ) triplet is one promising focusing strategy. In this paper, we investigate the performance of a PMQ triplet to fit the requirements of the electron beam properties in a plasma cell and discuss the realizable phase spaces for the LWFA experiment planned at SINBAD.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW027

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

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MOPGW047

Analysis and Simulation of the "After-Pulse" RF Breakdown

cavity, simulation, timing, GUI

196

X. Lin, H.B. Chen, Z.N. Liu, J. Shi, H. Zha
TUB, Beijing, People’s Republic of China
X.W. Wu
CERN, Meyrin, Switzerland

During the high power experiment of a single-cell standing-wave accelerating structure, it was observed that many RF breakdowns happen when the field inside cavity is decaying after the input rf pulse is off. The distribution of breakdown timing shows a peak at the moment of RF power switches off. A series of simulation was performed to study the after-pulse breakdown effect in such a standing-wave structure. A method of calculating poynting vector over time is proposed in this article to study the modified poynting vector at critical points in the cavity. Field simulation and thermal simulation were also carried out to analyse possible reasons for the after-pulse breakdown effect.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW047

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

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MOPGW067

On Coordinate Systems in Beam Dynamics

simulation, GUI, acceleration, FEL

243

E. Laface
ESS, Lund, Sweden

Any description of the beam dynamics calculation and simulation relies on the proper choice of a coordinate system in order to minimize the computational complexity and to apply different level of approximations in the calculations. This need generates a large number of reference systems, especially to describe the longitudinal dynamics of a particle beam like(z, z′),(t,∆P/P),(z, φ), etc. In this paper we summarize the rules to change coordinates systems, which system is canonical and how the Hamiltonian of the beam transforms according to the chosen coordinate system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW067

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

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MOPGW073

Beam Manipulation Using Self-Induced Fields at the SwissFEL Injector

FEL, simulation, electron, wakefield

266

S. Bettoni, P. Craievich, E. Ferrari, R. Ganter, F. Marcellini, E. Prat, S. Reiche
PSI, Villigen PSI, Switzerland
A.A. Lutman
SLAC, Menlo Park, California, USA
G. Penco
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

In the past years wakefield sources have been used to manipulate electron beams in accelerators. We recently installed corrugated structures for a total length of 2~m at the SwissFEL injector to test novel schemes for beam manipulations. We present simulations and early experimental results. We compare the model predictions with the measured data for the bunch energy losses and the kick factor, and show early results for the longitudinal phase space linearization and the production of current spikes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW073

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paper received ※ 09 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW105

Preliminary Lattice Studies for the Single-Invariant Optics Experiment at the University of Maryland

lattice, octupole, optics, resonance

367

L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, I. Haber, D.B. Matthew
UMD, College Park, Maryland, USA
K.J. Ruisard
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported through DOE-HEP Award DESC0010301 and NSF Award PHY1414681.
A novel approach to transverse resonance suppression in next generation high-intensity accelerators is the use of nonlinear optical elements to induce large tune spreads which result in reduced responses to resonance driving perturbations*. In order to test this theory, we have built and characterized an octupole channel insert for use in the University of Maryland Electron Ring (UMER). This paper presents experimental lattice studies using a low space-charge intensity beam at an energy of 10keV with a beam current of ~150uA, tune depression < 0.005, and unnormalized RMS emittance of 4.3 mm-mr. We apply beam based measurement techniques in order to evaluate the quality of our single-invariant lattice and better understand the nonlinearities created by the octupole channel.
* V. Danilov and S. Nagaitsev, Nonlinear accelerator lattices with one and two analytic invariants, PRSTAB, 13, 084002, 2010.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW105

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paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW113

Experimental Demonstration of the Henon-Heiles Quasi-Integrable System at IOTA

octupole, lattice, optics, alignment

386

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 National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report the first results of experimental investigation of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread and dynamic aperture preservation. Resilience to perturbations and imperfections in the lattice is explored. We conclude by outlining future research plans and discussing applicability to future high intensity accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW113

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

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MOPGW125

Lossless Crossing of 1/2 Resonance Stopband by Synchrotron Oscillations

resonance, lattice, betatron, storage-ring

410

G.M. Wang, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk
BNL, Upton, Long Island, New York, USA

Funding: DOE under contract No.DE-AC02- 98CH10886
Modern high performance circular accelerators require sophisticated corrections of nonlinear lattices. The beam betatron tune footprint may cross many resonances, reducing dynamic aperture and causing particle loss. However, if particles cross a resonance reasonably fast, the beam deterioration may be minimized. In this paper, we present the experiments with the beam passing through a half-integer resonance stopband via chromatic tune modulation by exciting synchrotron oscillations. This is the first time that beam dynamics have been kept under precise control while the beam crosses a half-integer resonance. Our results convincingly demonstrate that particles can cross the half-integer resonance without being lost if the passage is reasonably fast and the resonance stopband is sufficiently narrow.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW125

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

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MOPMP019

High Luminosity LHC Optics and Layout HLLHCV1.4

optics, luminosity, operation, cavity

468

R. De Maria, R. Bruce, D. Gamba, M. Giovannozzi, F. Plassard
CERN, Geneva, Switzerland

The goal of the High Luminosity Project is the upgrade of the LHC to deliver an integrated luminosity of at least 250 \rm fb^-1 per year in each of the two high-luminosity, general-purpose detectors ATLAS and CMS. This article presents the latest layout design and the corresponding optics features, which comprise optimisation of the orbit corrector and crab cavity systems, and new estimates of the performance reach thanks to the new concept of fully remote alignment. In addition, the new optics version incorporates improvements required by beam instrumentation, dump system, and collimation system, as well as low-beta solutions for the LHCb experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP019

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

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MOPMP024

Prospects for Future Asymmetric Collisions in the LHC

proton, luminosity, operation, hadron

484

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

The proton-lead runs of the LHC in 2012, 2013 and 2016 provided luminosity far beyond expectations in a diversity of operating conditions and led to important new results in high-density QCD. This has permitted the scope of the future physics programme to be expanded in a recent review. Besides further high-luminosity p-Pb collisions, lighter nuclei are also under consideration. A short proton-oxygen run, on the model of the 2012 p-Pb run, would be of interest for cosmic-ray physics. Other collision systems like proton-argon or collisions of protons with other noble gases are also discussed. We provide an overview of the operational strategies and potential performance of various asymmetric collision options. Potential performance limits from moving beam-beam encounters at injection and various beam-loss mechanisms are evaluated in the light of our understanding of the LHC to date.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP024

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

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MOPMP033

LHC Run 2 Optics Commissioning Experience in View of HL-LHC

optics, luminosity, coupling, simulation

508

R. Tomás, F.S. Carlier, J.M. Coello de Portugal, J. Dilly, S.D. Fartoukh, E. Fol, D. Gamba, A. Garcia-Tabares, M. Giovannozzi, M. Hofer, E.H. Maclean, L. Malina, T.H.B. Persson, P.K. Skowroński, M. Solfaroli, M.L. Spitznagel, A. Wegscheider, J. Wenninger, D.W. Wolf
CERN, Geneva, Switzerland

LHC Run 2 has achieved a beta lower than a factor 2 below design. This has significantly challenged optics measurement and correction techniques in the linear and non-linear regimes, leading to the development of new approaches. Furthermore, experimenting with a large variety of optics has allowed facing the difficulties of future optics and gaining understanding of the machine imperfections. A summary of these aspects is given in view of their implications for the HL-LHC Project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP033

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paper received ※ 07 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP052

Numerical Simulations of the DC Wire Prototypes in LHC for Enhancing the HL-LHC Performances

simulation, luminosity, optics, resonance

566

A. Poyet
Université Grenoble Alpes, Grenoble, France
S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, K. Skoufaris, G. Sterbini
CERN, Geneva, Switzerland

For the last 15 years, the compensation of the Beam-Beam Long-Range (BBLR) interaction in colliders using DC wires has been studied. In 2015, in the frame of the HL-LHC project, it has been shown that a compensation of all the Resonance Driving Terms (RDTs) generated by the BBLR interaction is possible using wires with constraints on their transverse and longitudinal positions. In 2017, an experimental campaign has been launched in the present LHC, with wires installed in sub-optimal positions due to integration constraints. The aim of this paper is therefore to apply the formalism developped for HL-LHC to the LHC case and to compare the experimental results to the numerical tracking studies of the compensation using wires.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP052

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

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MOPRB011

Progress on Muon Ionization Cooling Demonstration with MICE

simulation, emittance, detector, framework

594

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

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

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

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

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MOPRB013

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

plasma, emittance, focusing, electron

601

R. Pompili
INFN/LNF, Frascati, Italy

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

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

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

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MOPRB017

Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment

cavity, linac, DTL, coupling

606

Y. Nakazawa, H. Iinuma
Ibaraki University, Ibaraki, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
R. Kitamura, H.Y. Yasuda
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784.
An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB017

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paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPRB018

Conceptual Design of Negative-Muon Decelerator for Material Science

cavity, induction, impedance, power-supply

610

C. Ohmori, M. Otani, K. Shimomura
KEK, Tokai, Ibaraki, Japan
T. Takayanagi
JAEA/J-PARC, Tokai-mura, Japan

In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB018

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

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MOPRB023

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

emittance, rfq, polarization, acceleration

622

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

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

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

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

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MOPRB026

High-Quality Muon Beam Production Based on Superconducting Solenoids

target, proton, polarization, solenoid

630

Y. Bao, X. Li, Y. Li, Y.P. Song, X. Tong
IHEP, Beijing, People’s Republic of China

Funding: This work is supported by the Science Foundation of The Chinese Academy of Sciences and National Natural Science Foundation of China (No. 11875281)
In labs, muon beams are produced by protons hitting targets. The initial phase space of the muon beam is extremely large. In general, two types of muon collection methods have been used in the world. One is to put the muon production target in a superconducting solenoid, and low-energy muons are collected from the back of the target, then transported through a bent solenoid. In this way, a high-intensity muon beam can be collected, but the energy spread is wide and the beam polarization is low. For most muSR applications a surface muon beam with narrow energy bite and high polarization is required. Most muSR facilities are built with collecting magnets by the side of the target, in this way only a small fraction of muons with low emittance are collected and transported downstream. In this work we outline a muon collection method based on superconducting solenoid. Instead of using bent solenoids, a matching section with a dipole magnet is used to select muons with a certain momentum and match to downstream beamliines. A high-quality muon beam can be achieved with a high intensity and polarization. Such a method can be adapted to the MUSIC, Mu2e, and COMET muon beamlines after their dedicate experiments and convert the beamlines into a high quality muSR facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB026

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

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MOPRB036

Study on Beam-induced heating in injection section of Hefei Light Source

impedance, vacuum, kicker, radiation

652

D.R. Xu, W. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Ceramic chambers distributed with metal belts on the inner surface are installed in the injection section at Hefei Light Source (HLS). Heating on the ceramics chambers has been observed during machine operation. An air compressor is used to cool these chambers due to concerns of overheating during top-up operation mode. To understand the sources of the heating, a series of experiments are performed with various beam currents and bunch filling patterns. The study shows that the heating is mainly caused by the narrow-band impedances of the ceramic chambers and their adjacent vacuum components.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB036

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

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MOPRB043

Two-Beam Operation in DESIREE

pick-up, injection, detector, ion-source

659

A. Källberg, M. Björkhage, M. Blom, H. Cederquist, P. Reinhed, S. Rosén, H.T. Schmidt, A. Simonsson, H. Zettergren
Stockholm University, Stockholm, Sweden

The current status of DESIREE is described, with special emphasis on the setup for collision experiments with ions in both the two electrostatic rings - negative ions in one ring and positive in the other. By measuring the kinetic energy released in mutual neutralization reactions be-tween the two ions at collision energies close to zero eV in 3D, the population of different reaction channels has been obtained. The different steps necessary to set up the beams to get well controlled experimental properties are described as well as the principles behind our automatic optimization routines, which are extensively used with consistent result.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB043

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

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MOPRB049

Study of Beam-Gas Interactions at the LHC for the Physics Beyond Colliders Fixed-Target Study

target, proton, collider, simulation

673

C. Boscolo Meneguolo, R. Bruce, F. Cerutti, M. Ferro-Luzzi, M. Giovannozzi, A. Mereghetti, J. Molson, S. Redaelli
CERN, Geneva, Switzerland
A. Abramov
JAI, Egham, Surrey, United Kingdom

Among several working groups formed in the framework of Physics Beyond Colliders study, launched at CERN in September 2016, there is one investigating specific fixed-target experiment proposals. Of particular interest is the study of high-density unpolarized or polarized gas target to be installed in the LHCb detector, using storage cells to enhance the target density. This work studies the impact of the interactions of 7 TeV proton beams with such gas targets on the LHC machine in terms of particle losses.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB049

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paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPRB052

Gamma Factory at CERN: Design of a Proof-of-Principle Experiment

photon, laser, electron, cavity

685

Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann
CERN, Geneva, Switzerland
S.E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay
JAI, Egham, Surrey, United Kingdom
A. Apyan
ANSL, Yerevan, Armenia
E.G. Bessonov
LPI, Moscow, Russia
A. Bosco, S.M. Gibson, L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
F. Castelli
Università degli Studi di Milano, Milano, Italy
F. Castelli, C. Curatolo, L. Serafini
INFN-Milano, Milano, Italy
K. Kroeger
FSU Jena, Jena, Germany
A. Martens
LAL, Orsay, France
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy
M. Sapinski, T. Stöhlker
GSI, Darmstadt, Germany
G. Weber
IOQ, Jena, Germany
Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052

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paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB055

First Partially Stripped Ions in the LHC (208Pb⁸¹⁺)

injection, collimation, factory, operation

689

M. Schaumann, R. Alemany-Fernández, H. Bartosik, T. Bohl, R. Bruce, G.H. Hemelsoet, S. Hirlaender, J.M. Jowett, V. Kain, M.W. Krasny, J. Molson, G. Papotti, M. Solfaroli Camillocci, H. Timko, J. Wenninger
CERN, Geneva, Switzerland

The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron (208Pb⁸¹⁺) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few 208Pb⁸¹⁺ bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB055

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

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MOPRB056

THz Radiator Based on Photonic Band Gap Crystal for SwissFEL

electron, photon, GUI, FEL

693

L. Shi, R. Ischebeck, S. Reiche
PSI, Villigen PSI, Switzerland

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647.
The electromagnetic radiation in 1-20 THz has many unique properties when it interacts with matter due to its non-ionizing excitation in matter. Especially the dynamics of the excited matter can be probed with the help of X-ray pulses at a free electron laser facility, e.g. SwissFEL, to deepen our understanding of a wide range of phenomena. Due to its high research potential, various means of THz generation have been proposed and demonstrated. We investigate preliminarily here its generation based on a relativistic electron bunch and a photonic band gap crystal (PBG) made of dielectric rods. The PBG provides additional degrees of freedom for the THz pulse tuning. Additionally, the unwanted radiation parts can be damped by the structure in order to minimize the deleterious beam dynamics effects. The crystal also promises the integration of generation, filtering and coupling for transport into a single piece.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB056

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

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MOPRB063

Longitudinal Tomography in a Scaling FFA

synchrotron, cavity, proton, injection

719

D.J. Kelliher, C. Brown, J.-B. Lagrange, S. Machida, C.R. Prior, C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
Y. Ishi, Y. Kuriyama, H. Okita, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
S.L. Sheehy
JAI, Oxford, United Kingdom

In a synchrotron the rate of acceleration is limited by the ramp rate of the bending field. There is no such constraint in a Fixed Field alternating gradient Accelerator (FFA), allowing a much higher repetition rate and novel modes of operation such as beam stacking. It is of interest to obtain a picture of the longitudinal phase space from experimental data in order to diagnose the response of the beam to various RF programmes. Longitudinal tomography, already well established in synchrotrons, involves reconstructing the phase space using bunch monitor data obtained for a sufficient number of turns in a synchrotron oscillation. Here we reconstruct the longitudinal phase space using data from the 150 MeV scaling FFA at KURNS, Osaka, Japan.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB063

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

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MOPRB065

Enhancing Experimental Prospects With Low Energy Antiprotons

proton, antiproton, detector, cryogenics

727

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 programme under the Marie SkłodowskaCurie grant agreement No 721559.
The Extra Low Energy Antiproton ring (ELENA) is a critical upgrade to the Antiproton Decelerator (AD) at CERN and saw the first beam in 2018. ELENA will significantly enhance the achievable quality of low energy antiproton beams and enable new experiments. To fully exploit the potential of this new facility, advances are required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to fully characterize the beam’s properties, as well as in novel experiments that take advantage of the enhanced beam quality that ELENA can provide. These research areas are in the heart of the pan-European research and training network AVA (Accelerators Validating Antimatter physics) which started in 2017. This contribution presents research results within AVA on the performance of ultra-thin diamond membranes, electron cooling and beam life time studies of low energy ion and antiproton beams, as well as efficient integration and performance optimization of cryogenic detectors in ELENA and associated trap experiments. These results are used to describe the optimum layout of a state-of-the-art low energy antiproton facility and associated experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB065

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

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MOPRB069

Generation of High Power Short Rf Pulses using an X-Band Metallic Power Extractor Driven by High Charge Multi-Bunch Train

pick-up, multipactoring, acceleration, simulation

734

J.H. Shao, M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
H.B. Chen, M.M. Peng, J. Shi, H. Zha
TUB, Beijing, People’s Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
J. Seok
UNIST, Ulsan, Republic of Korea

Short pulse two-beam acceleration (TBA) is a structure wakefield acceleration (SWFA) approach aiming to achieve gradient above 250 MV/m using rf pulses less than 20 ns. An X-band 11.7 GHz metallic power extractor has been developed as the power source to test accelerating structures in this extreme regime. The power extractor is designed to be driven by high charge bunches separated by 769.2 ps (9 times the X-band period) on an L-band 1.3 GHz beamline. In the recent experiment, ~280 MW rf pulses with 3 ns flat-top have been measured by a coaxial rf pickup when driven by 8-bunch trains with a total charge of ~500 nC. The power level is ~50% lower than the theoretical prediction and simulation. Experimental investigation suggests that the missing power was mainly caused by the multipacting issue inside the rf pickup, which could be eliminated by a newly-designed directional coupler.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB069

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paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB087

Proposal for a High Transformer Ratio CW Dielectric Accelerator

electron, SRF, wakefield, operation

773

V. Litvinenko
Stony Brook University, Stony Brook, USA
J.C. Brutus, Y.C. Jing, I. Pinayev, G. Wang
BNL, Upton, Long Island, New York, USA
M.E. Conde, C.-J. Jing, J.G. Power
ANL, Argonne, Illinois, USA
A. Kanareykin
Euclid Beamlabs LLC, Bolingbrook, USA
N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA

Advanced CW accelerators are one of high priority directions identified by Advanced Accelerator Concepts Research Roadmap Workshop Report *. High transformer ratio of beam-driven accelerators is critically important for cost-effective FEL systems. We present a proposed experiment for demonstrating a high transformer ratio CW dielectric accelerator using operational SRF accelerator built for Coherent electron Cooling experiment. This accelerator operates with CW electron beam comprised of 78 kHz train of electron bunches. Electron bunches with controllable longitudinal and charge up to 10 nC per bunch are generated in 1.25 MV SRF photo-electron gun. This bunches are ballistically compressed to duration of 10-to-30 psec and accelerated to 15 MeV in SRF linac**. Such bunches would be excellent drivers of high-transformer ratio DWA accelerators. In this paper we present expected performance of proposed CW DWA accelerator.
*Advanced Accelerator Concepts Research Roadmap Workshop Report, 2016,
*V.N. Litvinenko et al., In proc.of FEL’17, Santa Fe, NM, USA, August 20-25, 2017, p. 132

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPRB088

Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab

undulator, electron, radiation, photon

777

I. Lobach
University of Chicago, Chicago, Illinois, USA
A. Halavanau, Z. Huang, V. Yakimenko
SLAC, Menlo Park, California, USA
K. Kim
ANL, Argonne, Illinois, USA
V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
A.Y. Murokh
RadiaBeam, Los Angeles, California, USA
T.V. Shaftan
BNL, Upton, Long Island, New York, USA

We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab with an InGaAs PIN photodiode and an integrating circuit. Our study was motivated by the previous experiment *. We propose a theoretical model for the experimental data from * and in our own experiment we attempted to verify the model in an independent and more systematic way. Moreover, these fluctuations are an interesting subject for a study by itself, since they act as a seed for SASE in FELs. We improve the precision of the measurements from * by subtracting the average signal amplitude using a comb filter with a one-turn IOTA delay, and by using a special algorithm for noise subtraction. We obtain a reasonable agreement between our theoretical model and experiment. Along with repeating the experiment from *, which was performed at a constant beam current, we also collect data for fluctuations in undulator light at different beam current values. Lastly, in our experiment we were able to see the transition from Poisson statistics to Super-Poisson statistics for undulator light, whereas in * only the latter statistics was observed.
* M. Teich et al., PRL, vol. 65, no. 27, p. 3393 (1990).

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

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MOPRB089

Experimental Study of a Single Electron in a Storage Ring via Undulator Radiation

photon, electron, undulator, radiation

781

S. Nagaitsev, A.L. Romanov, G. Stancari
Fermilab, Batavia, Illinois, USA
A. Arodzero, A.Y. Murokh, M. Ruelas
RadiaBeam, Santa Monica, California, USA
I. Lobach
University of Chicago, Chicago, Illinois, USA
T.V. Shaftan
BNL, Upton, Long Island, New York, USA

A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.

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

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MOPRB104

A Parameter Study for Improving the Performance of the Production Target for the Fermilab Muon g-2 Experiment

target, simulation, storage-ring, proton

806

D. Stratakis
Fermilab, Batavia, Illinois, USA

The target station of the Muon g-2 Experiment is one of the central pieces for the production of secondary pions which eventually will decay to the desired mu-ons. In this paper, we report adjustments made to opti-mize its performance. For instance, in the simulation we vary the size of the primary incoming beam and examine its impact on the downstream production. We then compare this with the actual measured beam size upstream of the target. In addition, we examine the sensitivity in performance with the strength of the lithium lens for pion capture and the distance between lens and target. We compare measured data with simu-lation results.

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

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MOPRB105

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

quadrupole, emittance, framework, simulation

810

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

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

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

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

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MOPTS005

Status of the SPIRAL2 Project

linac, neutron, MMI, proton

844

P. Dolegieviez, R. Ferdinand, X. Ledoux, H. Savajols, F. Varenne
GANIL, Caen, France

The SPIRAL2 facility at GANIL will use a high-power p, d and heavy-ion superconducting linac for a wide range of applications including RIB production using both ISOL and in-flight techniques. The SPIRAL2 phase 1 deals with the high-power superconducting linac with two experimental areas called ’Neutrons for Science’ (NFS) and ’Super Separator Spectrometer’ (S3). The low energy experimental hall DESIR, under construction, will further increase the possibility for physics experiments. All the linac is installed, the commissioning of the injec-tor part (two sources and the A/Q = 3 RFQ) and two cool down of the entire superconducting linac have been suc-cessfully done. We are now in the linac beam commis-sioning phase. The project scope and parameters, the constraints linked to the safety rules, the accelerator, NFS, S3 and DESIR status and the planning will be pre-sented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS005

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

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MOPTS014

The Experimental Area at the ARES LINAC

laser, electron, linac, acceleration

867

F. Burkart, R.W. Aßmann, U. Dorda, J. Hauser, S. Lederer, F. Lemery, B. Marchetti, F. Mayet, E. Panofski, P. Wiesener
DESY, Hamburg, Germany
M. Trunk
University of Hamburg, Hamburg, Germany

The ARES (Accelerator Research Experiment at SINBAD) linac at the accelerator R&D facility SINBAD (Short innovative bunches and accelerators at DESY) will drive multiple independent experiments including the acceleration of ultrashort electron bunches. In addition the linac will host an experimental area, open for transnational access, to study advanced high gradient, laser driven, acceleration concepts, like the ones studied within the ACHIP (accelerator on a chip) project. The area will be operational mid-2019. This paper will report on the current status of the experimental area, including hardware parameters, beam optics, achievable beam parameters, design of the experimental chamber and commissioning plans. The modification plans for a micro-bunching experiment in the frame of the ACHIP experiment and future upgrade plans will be shown and discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS014

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

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MOPTS026

Status Report of the SINBAD-ARES RF Photoinjector and LINAC Commissioning

gun, linac, electron, laser

906

E. Panofski, R.W. Aßmann, F. Burkart, U. Dorda, K. Flöttmann, M. Hüning, B. Marchetti, D. Marx, F. Mayet, P.A. Walker, S. Yamin
DESY, Hamburg, Germany

The accelerator R&D facility SINBAD (Short innovative bunches and accelerators at DESY) will drive multiple independent experiments including the acceleration of ultrashort electron bunches and the test of advanced high gradient acceleration concepts. The SINBAD-ARES (Accelerator Research Experiment at SINBAD) setup hosts a normal conducting RF photoinjector generating a low charge electron beam that is afterwards accelerated to 100 MeV by an S-band linac section. The linac as well as a magnetic chicane allow the production of ultrashort pulses with an excellent arrival-time stability. The high brightness beam has then the potential to serve as a test beam for next generation compact acceleration schemes. The setup of the SINBAD-ARES facility will proceed in stages. We report on the current status of the ARES RF gun and linac commissioning.

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

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MOPTS028

Search for Electric Dipole Moments at Cosy in Jülich - Spin-Tracking Simulations Using Bmad

simulation, dipole, storage-ring, alignment

914

V. Poncza, A. Lehrach
FZJ, Jülich, Germany
A. Lehrach, V. Poncza
RWTH, Aachen, Germany

The observed matter-antimatter asymmetry in the universe cannot be explained by the Standard Model (SM) of particle physics. In order to resolve the matter dominance an additional CP violating phenomenon is needed. A candidate for physics beyond the SM is a non-vanishing Electric Dipole Moment (EDM) of subatomic particles. Since permanent EDMs violate parity and time reversal symmetries, they are also CP violating if the CPT -theorem is assumed. The JEDI (Jülich Electric Dipole moment Investigations) collaboration in Jülich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. In order to analyse the data and to disentangle the EDM signal from systematic effects spin tracking simulations are needed. Therefore a model of COSY was implemented using the software library Bmad. It includes the measured magnet misalignments of the latest survey and a simplified description of the RF-Wien Filter device that is used for the EDM measurement. The model was successfully benchmarked using analytical predictions of the spin behavior. A crucial point regarding the data analysis is the knowledge of the orientation of the invariant spin axis with vanishing EDM at the position of the RF-Wien Filter. Especially its radial component is unknown and spin tracking simulations can be used to determine this missing number. Tracking results as well as the algorithm to find the invariant spin axis will be presented.

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paper received ※ 25 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS046

Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC

rfq, linac, operation, MMI

960

Y. Kondo, K. Hirano, T. Ito, N. Kikuzawa, R. Kitamura, T. Morishita, H. Oguri, K. Ohkoshi, S. Shinozaki, K. Shinto
JAEA/J-PARC, Tokai-mura, Japan
Z. Fang, Y. Fukui, K. Futatsukawa, K. Ikegami, T. Miyao, K. Nanmo, M. Otani, T. Shibata
KEK, Ibaraki, Japan
T. Hori, Y. Nemoto, Y. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan
T. Ishiyama, Y. Sawabe
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
Y. Ito
Total Saport System Corp., Naka-gun, Ibaraki, Japan
Y. Kato
Total Support Systems Corporation, Tokai-mura, Naka-gun, Ibaraki, Japan
F. Kobayashi
ULVAC Human Relations, Ltd., Kanagawa, Japan
D. Takahashi, R. Tasaki
KIS, Ibaraki, Japan

We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented.

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

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MOPTS052

Simulation of Electric and Thermal Behavior of Cryogenic Three-cell Copper Accelerating Cavity for High Gradient Experiments

cavity, simulation, cryogenics, coupling

980

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

A C-band three-cell pi-mode accelerating cavity made of high purity copper is under design for use in ultra-high accelerating gradient experiments at a cavity temperature of 20 K. The basic configuration, consisting of mode converter, short circular waveguide and cells with round periphery, is the same as that which was previously employed in the cold model for a 2.6-cell photocathode electron gun cavity. Though the 0.6-cell part in the previous model is replaced with a full cell having a beam duct, the overall electric property of the cavity will not change significantly. The RF input coupling coefficient is adjusted to around 10 at 20 K, which is expected to be lowered significantly due to the increase in the surface resistance by the rapid temperature rise during a high power RF input. The results of the simulations on the electric field and the temperature rise along the cavity surface during the RF pulse are discussed in the report.

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paper received ※ 13 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPTS054

Status of the CLEAR Electron Beam User Facility at CERN

electron, radiation, plasma, operation

983

K.N. Sjobak, E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek
CERN, Geneva, Switzerland
A. Lyapin
UCL, London, United Kingdom

The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.

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

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MOPTS075

Design and Experiment of a Window-Type CW Deuteron RFQ

rfq, cavity, operation, Windows

1021

K. Zhu, M.J. Easton, P.P. Gan, S.L. Gao, H.P. Li, S. Liu, Y.R. Lu, Q.Y. Tan, L. Tao, Z. Wang
PKU, Beijing, People’s Republic of China
W.P. Dou, Y. He, C. Wang, Q. Wu, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

A deutron CW RFQ was designed and fabricated in Peking University. It will accelerate 50mA CW deutron beam from 50keV to 1MeV at 162.5MHz. The novel structure of four-vane with window was used to seperate the dipole mode from the working mode. The field tuning of this RFQ was different from conventional four vane RFQ because that the four quadrants of RFQ cavity were coupled. The discipline of field tuning was studied by simulation and experiment. The beam dynamics of the RFQ was designed by equipartation and matching method, limit current effect was considered at the same time. The final design result of the RFQ was: voltage between electrodes was 60kV, transport efficiency of RFQ is 98%, field unflatness is less than 2% after tuning, the deformation of RFQcavity is less than 80um. Only 47 hours was spent to increase CW power of cavity from 0 to 55kW in high power test and The RFQ can working stable at the design voltage. The preliminary H²⁺ beam exeperiment has been done and 1.78mA CW beam was obtained at exit of RFQ. This paper will introduce the detail of design and experiment of the RFQ.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS075

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

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MOPTS080

Status and Installation Plan of RISP RFQ at Project Site

rfq, site, cavity, resonance

1031

B.-S. Park, I.S. Hong
IBS, Daejeon, Republic of Korea

Funding: Supported by the Rare Isotope Science Project of Institute for Basic Science funded by the Ministry of Science, ICT (MSIP) and the National Research Foundation (NRF) of Korea (2013M7A1A1075764).
The Rare Isotope Science Project (RISP) at Institute for Basic Science (IBS) has been developed a Radio Frequency Quadrupole(RFQ), which was fabricated and commissioned at the off-site test facility. An O+7 beam was accelerated from 10keV/u to 516keV/u as a preliminary beam test. For CW and high power operation, RF conditioning test was also conducted. The RISP RFQ is 5 meters long, 1 meter in diameter and weighs about 16 tons. It was disassembled and transported to the project site, Sin-dong, for installation as the injector system. The installation commenced in April 2019 and the commissioning of the injector system is expected to begin in early 2020. In this paper, the installation status and plans were summarized.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS080

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

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MOPTS090

Beam-Based Measurement of the Skew-Sextupolar Component of the Radio Frequency Field of a HL-LHC-Type Crab-Cavity

cavity, betatron, sextupole, damping

1066

M. Carlà, A. Alekou, H. Bartosik, L.R. Carver
CERN, Geneva, Switzerland

Two High Luminosity Large Hadron Collider (LHC) type crab-cavities have been installed in the CERN SPS for testing purposes. An attempt to characterize the skew-sextupolar component of the radio frequency field of the crab-cavity (a3) has been carried out by means of beam-based techniques using turn-by-turn monitoring of the betatron motion. The skew nature of a3 couples the horizontal and vertical betatron motions through a non-linear term. Therefore by exciting the horizontal betatron motion it was possible to observe a spectral line in the vertical beam motion driven by the non-linear coupling at the characteristic frequency 2Qx. A measurement of the magnitude of a3 was thus obtained by characterizing amplitude and phase of such line. The results of the measurements are discussed here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS090

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

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MOPTS091

Mechanical Robustness of HL-LHC Collimator Designs

site, proton, interface, radiation

1070

F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis
CERN, Meyrin, Switzerland

Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project.
Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091

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

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MOPTS092

Numerical and Experimental Evaluation of the DQW Crab Cavity Cryomodule Thermal Budget

cryomodule, cavity, HOM, radiation

1074

F. Carra, K. Brodzinski, E. Cano-Pleite, O. Capatina
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
One of the key devices of the HL-LHC project are SRF Crab Cavities. A cryomodule with two Double Quarter Wave (DQW) crab cavities has been fabricated at CERN in 2017 and successfully tested with beam in the Super Proton Synchrotron (SPS) in 2018. The aim of the present study is to present and compare the estimation of the thermal budget for the different components of the cryomodule, performed with numerical and semi-analytical methods, with the experimental measurements carried out on the cryomodule after installation in the SPS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS092

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

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TUXXPLS2

Negative Muonium Ion Production With a C12A7 Electride Film

target, positron, acceleration, electron

1175

M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, K. Shimomura, T. Yamazaki
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Inami, M. Yotsuzuka
Nagoya University, Nagoya, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
R. Kitamura, H.Y. Yasuda
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work was supported by OSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707.
Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H⁻ formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented.

Slides TUXXPLS2 [2.680 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS2

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

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TUZZPLM3

The EPICS Software Framework Moves from Controls to Physics

EPICS, controls, detector, database

1216

G.R. White, M.V. Shankar
SLAC, Menlo Park, California, USA
T.M. Cobb
DLS, Oxfordshire, United Kingdom
L.R. Dalesio, M.A. Davidsaver
Osprey DCS LLC, Ocean City, USA
S.M. Hartman, K.-U. Kasemir, M.R. Pearson, K. Vodopivec
ORNL, Oak Ridge, Tennessee, USA
D.G. Hickin
EuXFEL, Schenefeld, Germany
A.N. Johnson, M.L. Rivers, G. Shen, S. Veseli
ANL, Argonne, Illinois, USA
H. Junkes
FHI, Berlin, Germany
M.G. Konrad, G. Shen
FRIB, East Lansing, Michigan, USA
T. Korhonen
ESS, Lund, Sweden
M.R. Kraimer
Self Employment, Private address, USA
R. Lange
ITER Organization, St. Paul lez Durance, France
M. Sekoranja
Cosylab, Ljubljana, Slovenia
K. Shroff
BNL, Upton, Long Island, New York, USA
D. Zimoch
PSI, Villigen PSI, Switzerland

The Experimental Physics and Industrial Control System (EPICS), is an open-source software framework for high-performance distributed control, and is at the heart of many of the world’s large accelerators and telescopes. Recently, EPICS has undergone a major revision, with the aim of better computing supporting for the next generation of machines and analytical tools. Many new data types, such as matrices, tables, images, and statistical descriptions, plus users’ own data types, now supplement the simple scalar and waveform types of the former EPICS. New computational architectures for scientific computing have been added for high-performance data processing services and pipelining. Python and Java bindings have enabled powerful new user interfaces. The result has been that controls are now being integrated with modelling and simulation, machine learning, enterprise databases, and experiment DAQs. We introduce this new EPICS (version 7) from the perspective of accelerator physics and review early adoption cases in accelerators around the world.

Slides TUZZPLM3 [4.271 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZZPLM3

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

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TUPMP004

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

electron, proton, vacuum, ECR

1236

S. Bilgen, C. Bruni, B. Mercier, G. Sattonnay
LAL, Orsay, France
V. Baglin
CERN, Geneva, Switzerland

Funding: work supported by FCC project (CERN & LAL-CNRS-IN2P3)
Ultra-High Vacuum is an essential requirement to reach design performances in high-energy particle colliders. For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. Studies were performed on the ions, produced by molecular ionization generated by the proton beam and the electron cloud, and stimulating molecular desorption by the surface bombardment. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector (VPS)*, to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated.
* 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-IPAC2019-TUPMP004

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

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TUPMP007

DYVACS (DYnamic VACuum Simulation) Code: Calculation of Gas Density Profiles in Presence of Electron Cloud

electron, vacuum, proton, photon

1244

G. Sattonnay, S. Bilgen, B. Mercier
LAL, Orsay, France
V. Baglin
CERN, Meyrin, Switzerland

The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 (and then PyVASCO**) is already used to estimate vacuum stability and density profiles in steady state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds. Therefore, we propose an upgrade of this code by introducing electron cloud maps*** to estimate the electron density and the ionization of gas by electrons, leading to an increase of both electron- and ion-induced desorption. Results obtained with the new code (called DYVACS for DYnamic VACuum Simulation) will be compared to pressure measurements in the VPS sector**** of the LHC.
* A. Rossi, Tech. Rep., LHC Proj. Note 341
** I. Aichinger, et al arXiv:1707.07525
*** T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007)
**** B. Henrist et al, Proc. IPAC2014, Dresden

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP007

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

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TUPMP020

The Research on the Calibration of Direct-Current Current Transformers

power-supply, collider, factory, data-acquisition

1280

C. Han, Y. Gao, X.L. Guo, P. Liu
IHEP, Beijing, People’s Republic of China

The measurement accuracy of direct current-current transformer (DCCT) is one of the key factors influencing the output of high-precision direct current power supply. In this paper, a calibration system designed by measuring resistance principle with a high accuracy direct current comparator (DCC) was presented for DCCT whose measurement accuracy is better than 10^-5. The system can achieve high-precision calibration of DCCT within the measurement range of 0-400 A, and the uncertainty of the system calibration is better than 1.1×10-6 in the whole range. The accuracy and linearity of DCCT are tested to verify the accuracy of the whole calibration system, thereby the current accuracy of the magnet power supply can be further improved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP020

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

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TUPMP025

Design of Fast Corrector Magnet Power Supply for HEPS

power-supply, controls, simulation, radiation

1294

P. Liu, C. Han, F. Long
IHEP, Beijing, People’s Republic of China

High energy photon source is a fourth-generation synchrotron radiation light source with energy of 6Gev and ultra-low emittance (<0.1nm’rad). The ultra-low beam emittance requires high beam stability. Therefore, we develop a fast correction power supply with high bandwidth and low current ripple to improve the performance of the fast close orbit correction sys-tem to prove the high beam stability. The power supply adopts FPGA for full-digital control and use high speed ADC with temperature control. The power sup-ply has a small signal-bandwidth of 10 kHz and output current ripple lower than 20ppm. In this paper, we will describe the hardware design and software control methods and the test results will be demonstrated

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP025

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

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TUPMP029

Establishing a Laser Treatment to Suppress the Secondary Electron Emission

laser, electron, synchrotron, focusing

1303

Y.G. Wang, X.Q. Ge, X.T. Pei, S.W. Wang, Y. Wang, B. Zhang, B.L. Zhu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Laser treatment has a significant inluent on suppressing the secondary electron emission(SEE). The new synchrotron radiation light source, the Hefei Advanced Light Source(HALS) has a strict requirement on the SEE. In this paper, we used a 355nm laser to process copper sample. After the laser treatment, the secondary electron yield(SEY) reduced from 2.05 to 0.86. We used the scanning electron microscope(SEM) to analysis the surface of sample after the laser treatment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP029

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

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TUPMP031

Research on Secondary Electron Emission Characteristics of Diamond-like Carbon Thin Films

electron, vacuum, laser, gun

1306

Y.X. Zhang, X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, B.L. Zhu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In modern particle accelerators, the build-up of electron cloud is a main limiting factor for the achievement of high-quality beam. Among the techniques to mitigate it, coating the internal walls of the beam pipes with a thin film which has a low secondary electron yield (SEY) is considered to be one of the most effective means. From several earlier studies, it was found that diamond-like carbon (DLC) thin films are potential coatings. This paper is mainly about the research on secondary electron emission characteristics of DLC thin films. The secondary electron emission (SEE) tests were done at temperature of 298 K and vacuum pressure of 2×10^-9 Torr. Here, we obtained the characteristics of the SEE from DLC film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. The maximum secondary electron yield (SEY), δmax, of the DLC thin films under different primary electron doses were also obtained, respectively.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP031

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP032

Design of Analog to Digital Converter Scheme for High - Precision Electromagnet Power supply

controls, FEL, hardware, dipole

1309

M.J. Kim, Choi. Choi
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Han, S.-H. Jeong, Y.G. Jung, H.-S. Kang, D.E. Kim, H.-G. Lee, S.B. Lee, S.J. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Kim
Dongguk University, Seoul, Republic of Korea

This paper deals with the design of an analogue-to-digital converter (ADC) scheme for a highly precise magnet current supply (MPS). The MPSs are requires with stable and precise current specification in range of the ppm. To meet the requirements, the AD circuit is composed of parallel ADCs of low-medium resolution. Digitally, the oversampling and averaging are performed to increase both the effective resolution and the signal to noise ratio (SNR). The implemented AD circuit was improved about 18 dB (32 times oversampling). The MPS applied by the proposed ADC scheme provides more precise control and the stable current within 10 ppm at 200 A. The experiment used a dipole magnet of the PAL-XFEL and its results proved feasibility through precisely measurable DVM3458A (Keysight Co.).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP032

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

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TUPMP036

Results on the FCC-hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kararesults on the Fcc-Hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kara

photon, radiation, vacuum, electron

1323

L.A. Gonzalez, V. Baglin, I. Bellafont, P. Chiggiato, C. Garion, R. Kersevan
CERN, Geneva, Switzerland
I. Bellafont, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
S. Casalbuoni, E. Huttel
KIT, Eggenstein-Leopoldshafen, Germany

Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
In the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of the FCC-hh beam screen (BS) prototype has been carried out with the aim of testing it at room temperature on the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator) light source. The BS prototype was tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power match quite well the one foreseen for the 50+50 TeV FCC-hh proton collider. The BS prototype (2 m in length) was manufactured according to the base line design (BD) of the FCC-hh BS. It implements a saw-tooth profile designed to absorb the SR generated at the bending magnets. Also, a laser-ablated anti-electron cloud surface texturing [2] was applied at the BS inner walls. We present here the results obtained at BESTEX and the comparison of the results obtained during irradiation of the saw-tooth profile at different geometric configurations.
This activity has been carried out in the framework of the EuroCirCol* collaboration (work package 4 "Cryogenic Beam Vacuum System").

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP036

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

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TUPMP039

Data-driven Controller Design Using the CERN Power Converter Control Libraries (CCLIBS)

controls, interface, factory, survey

1335

A. Nicoletti, M. Martino
CERN, Geneva, Switzerland

The data-driven control approach is a control methodology in which a controller is designed without the need of a model. Parametric uncertainties and the associated unmodeled dynamics are therefore irrelevant; the only source of uncertainty comes from the measurement process. The CERN Power Converter Control Libraries (CCLIBS) have been updated to include data-driven H-infinity control methods recently proposed in literature. In particular, a two-step convex optimization algorithm is performed for obtaining the 2-degree-of-freedom controller parameters. The newly implemented tools in CCLIBS can be used both for frequency response measurement of the load and for controller synthesis. A case study is presented where these tools are used for an application in the CERN East Area Renovation Project for which a high-precision 900 A trapezoidal current pulse is required with 450 ms flat-top and 350 ms ramp-up and ramp-down times. The tracking error must remain within ± 100 parts-per-million (ppm) during the flat-top (before the ramp-down phase starts). The magnet considered in the case study is of non-laminated iron type, hence the necessity of data-driven techniques since the dynamics of such a magnet is difficult to be modeled accurately (due to eddy currents losses). The Power Converter used is a SIRIUS 2P (with a current and voltage rating of 400 Arms and 450 V, respectively) whose digital control loop is regulated at a sampling rate of 5 kS/s.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP039

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paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP040

Impact of Flux Jumps on High-Precision Powering of Nb₃Sn Superconducting Magnets

simulation, controls, superconducting-magnet, superconductivity

1338

M. Martino, P. Arpaia, S. Ierardi
CERN, Geneva, Switzerland

Nb₃Sn superconducting magnets represent a technology enabler for future high-energy particle accelerators. A possible impediment, though, comes from flux jumps that, so far, could not be avoided by design unlike for NbTi technology. However, the impact of flux jumps on the powering has not been properly investigated to date. Flux jumps appear during current ramps at relatively low value of current and tend to disappear towards nominal current. They are usually detected as voltage jumps between different magnet coils but they might also produce overall voltage jumps across the magnet electrical terminals. Such jumps might perturb the power converter feedback control loop and therefore potentially jeopardize its precision performance during energy ramps. This work aims at : (i) presenting preliminary experimental test results on some HL-LHC Nb₃Sn model and prototype magnets, and (ii) attempting to build a simplified electrical model of the flux jumps (with focus only at its interaction with the power converter feedback control loop). Such work is a starting point for outlining possible power converters control strategies able to minimize flux jumps impact on high-precision powering of Nb₃Sn superconducting magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP040

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paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP041

Preliminary Design of RF-Shielded Bellows

wakefield, interface, vacuum, shielding

1341

Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang
NSRRC, Hsinchu, Taiwan

A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041

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paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP044

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

vacuum, impedance, photon, emittance

1347

G.Y. Hsiung
NSRRC, Hsinchu, Taiwan

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

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

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

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TUPGW019

Progress of the BESSY VSR Cold String Development and Testing

cavity, GUI, simulation, vacuum

1434

H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Tannert, A.V. Vélez, D. Wolk, N. Wunderer
HZB, Berlin, Germany
J. Guo, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW019

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paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW024

Pulse Shaping Methods for Laser-Induced Generation of THz Radiation at the Delta Storage Ring

laser, radiation, electron, storage-ring

1453

C. Mai, B. Büsing, A. Glaßl, S. Khan, D. Krieg, A. Meyer auf der Heide
DELTA, Dortmund, Germany

At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches to give rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW024

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

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TUPGW028

Low Energy Beam Transport System for MESA

emittance, cavity, laser, solenoid

1461

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

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

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

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

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TUPGW038

Study on Coherent THz Radiation Using Tilt Control of Electron Beam

electron, radiation, solenoid, target

1489

Y. Tadenuma, M. Brameld, T. Murakami, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

Funding: This work was supported by a research granted from JSPS KAKENHI 17H02821.
The terahertz wave is located in the intermediate frequency band between radio waves and light waves, and researches on the light sources such as terahertz quantum cascade laser and femtosecond laser based THz sources are being conducted*. As a new terahertz light source, we are studying coherent Cherenkov radiation by using the tilt control of electron beam and irradiating the target medium. Since the radiation intensity of Cherenkov radiation depends on the target medium, comparison of three kinds of medium with different refractive index and density, and optimization of the target shape were performed. In addition, we are going to try quasi monochromatization of radiation by using multi slit to control the form factor of the electron beam. In this presentation, we will report the experimental results of target optimization and quasi monochromatization and the future prospects.
*S. S. Dhillon, et al., The 2017 terahertz science and technology roadmap, J. Phys. D: Appl. Phys., 50 (2017) 043001.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW038

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW094

First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization

quadrupole, storage-ring, operation, emittance

1631

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

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

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

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

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TUPRB001

Nanosecond Pulsing for Tandem Accelerator

controls, bunching, linac, injection

1673

P. Linardakis, N.R. Lobanov, D.C. Tempra
Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia

Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism
A pulsed system capable of delivering up to a few microampere bursts of ions with mass range M=1 - 100 amu with a duration of approximately 1 ns is described. The system consists of a negative ion source, three frequency harmonic buncher - which uses the entire tandem electrostatic accelerator as a drift path to produce bunched ion bursts at the targets or linac entry - and high energy choppers. The buncher consists of a single acceleration gap with aligned retractable grids.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB001

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

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TUPRB004

Magnetic Measurements of Insertion Devices Using the Vibrating Wire Technique

vacuum, simulation, insertion-device, hardware

1683

C.K. Baribeau, D. Bertwistle, E.J. Ericson, J.T. Gilbert, T.M. Pedersen
CLS, Saskatoon, Saskatchewan, Canada

The commissioning of new in-vacuum insertion devices (ID) at the Canadian Light Source has motivated the assembly and development of a vibrating wire system. The advantage of the technique is that it is a sensitive magnetic measurement instrument at relatively low cost. Moreover, most hall probe systems require transverse access, which is often not available for in-vacuum or Delta-like devices. It is comparatively simple to string a taut wire through the gap of an in-vacuum ID. We describe the experimental challenges in mapping the field of an 80 mm period in-vacuum wiggler, IVW80, using the vibrating wire technique, and compare results against simulation and data obtained from Hall probe measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB004

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paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB008

LUXE - a QED Experiment at the European XFEL

FEL, electron, laser, photon

1694

F. Burkart, R.W. Aßmann, R. Brinkmann, W. Decking, N. Golubeva, B. Heinemann, M. Hüning, J. List, M. Wing
DESY, Hamburg, Germany
M. Wing
UCL, London, United Kingdom

The proposed experiment aims to measure QED in the presence of strong fields and above the Schwinger critical field. An experiment is being considered at the European XFEL, which should be able to measure non-perturbative QED and its transition from the perturbative regime. This paper presents the current status of the LUXE (Laser und XFEL Experiment) design study. First layout considerations; accelerator beam line design, electron and laser beam parameters, radioprotection issues and first results of the start to end simulations will be presented and discussed in detail. An outlook concerning the implementation into the XFEL schedule and timeline of this experiment will be given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB008

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

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TUPRB018

Design Studies of a Proof-of-Principle Experiment on THz SASE FEL at PITZ

FEL, undulator, laser, electron

1713

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

A free-electron laser based THz source is undergoing design studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). It is considered as a prototype for pump-probe experiments at the European XFEL, benefiting from the fact that the electron beam from the PITZ facility has an identical pulse train structure as the XFEL pulses. In the proposed proof-of-principle experiment, the electron beam (up to 4 nC bunch charge and 200 A peak current) will be accelerated to 16-22 MeV/c to generate SASE radiations in an LCLS-I undulator in the THz range between 60 and 100 µm with an expected energy of up to ~1 mJ/pulse. In this paper, we report our simulations on the optimization of the photo-injector and the design of the transport and matching beamline. Experimental investigations on the generation, characterization and matching of the high charge beam in the existing 22-m-long beamline will also be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB018

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

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TUPRB025

Harmonic Lasing of the European XFEL in the Angstrom Regime

FEL, undulator, photon, operation

1740

E. Schneidmiller, F. Brinker, W. Decking, D. Nölle, M.V. Yurkov, I. Zagorodnov
DESY, Hamburg, Germany
N. Gerasimova, J. Grünert, N.G. Kujala, J. Laksman, Y. Li, J. Liu, Th. Maltezopoulos, I. Petrov, L. Samoylova, S. Serkez, H. Sinn, F. Wolff-Fabris
EuXFEL, Hamburg, Germany

Harmonic lasing in XFELs is an opportunity to extend the photon energy range of existing and planned X-ray FEL user facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam. Another interesting application is Harmonic Lasing Self-Seeding (HLSS) that allows to improve longitudinal coherence and spectral power of a Self-Amplified Spontaneous Emission (SASE) FEL. This concept was successfully tested at FLASH2 in the range of 4.5 - 15 nm and at PAL XFEL at 1 nm. In this contribution we present recent results from the European XFEL where we successfully demonstrated operation of HLSS FEL at 5.9 A, thus pushing harmonic lasing for the first time into the Angstrom regime.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB025

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paper received ※ 09 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB031

FERMI Configuration for the Echo Enabled Harmonic Generation Experiment

laser, FEL, electron, photon

1752

E. Allaria, D. Castronovo, M. Cautero, I. Cudin, M.B. Danailov, B. Diviacco, L. Giannessi, M. Veronese, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The FERMI FEL-2 undulator line, normally operated in the double stage high gain harmonic generation with the fresh bunch (HGHG-FB) has been temporary modified to allow operating the FEL in the Echo Enabled Harmonic Generation (EEHG) scheme. An increase of the dispersion in the delay-line was required together with a replacement of the second stage modulator allowing the electron beam to resonantly interact with a second seed laser. Another critical component of the EEHG setup is a new manipulator installed in the delay-line chicane and hosting additional diagnostic components. In this work we describe in some detail these new components that allowed a successful demonstration of the EEHG at harmonics as high as 101.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB031

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

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TUPRB035

Stimulated Emission of THz Coherent Diffraction Radiation in an Optical Cavity by a Multibunch Electron Beam

cavity, radiation, resonance, electron

1763

Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, T. Uchiyama, N. Yamamoto
KEK, Ibaraki, Japan

Funding: JSPS KAKENHI
Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broad-band source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme to resonantly excite optical cavity modes of THz spectrum range via coherent diffraction radiation has been proposed. The confocal cavity design is the special case that resonance conditions of all the eigen modes coincide, resulting in realizing broad-band excitation. But in general cases of non-confocal cavities, the resonance condition depends on the mode, and the resonance peak becomes wide and weak. We performed an experiment with a non-confocal cavity as a follow-up experiment of that we have done with a confocal cavity. The result confirmed that the confocal design is the key for a broad-band source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB035

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB037

Experimental Demonstration of Vector Beam Generation With Tandem Helical Undulators

polarization, undulator, radiation, simulation

1766

S. Matsuba
HSRC, Higashi-Hiroshima, Japan
M. Fujimoto, M. Katoh
UVSOR, Okazaki, Japan
M. Hosaka
Nagoya University, Nagoya, Japan
K. Kawase
QST, Tokai, Japan
T. Konomi, N. Yamamoto
KEK, Ibaraki, Japan
A. Miyamoto
Toshiba, Yokohama, Japan
S. Sasaki
ANL, Argonne, Illinois, USA

Vector beam is a light beam with spatially modulated polarization state across the beam. Particular examples of vector beam are radial and azimuthal polarization which have donut-shaped intensity and radially and azimuthally oriented linear polarization state. Vector beam has long been interest in the laser community and it is well known that vector beam can be created by superposing two optical vortex beams which have spiral wave fronts. It has been demonstrated that optical vortex beam can be generated from a helical undulator as harmonics. Therefore, we propose a scheme to generate vector beam by superposing two optical vortex beams from two helical undulators in tandem, based on the principle of the ’crossed undulator’. The experiment was carried out at UVSOR BL1U. In this paper, we describe the principle and the experimental details.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB037

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

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TUPRB038

Characteristics of Polarized Coherent Radiation in Thz Region From a Crossed-Undulator

undulator, radiation, polarization, electron

1769

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

A variable polarized THz light source using a crossed-undulator configuration has been developed at Research Center for Electron Photon Science (ELPH), Tohoku University. It consists of two planar undulators of which deflecting planes cross at right angles and a phase shifter for phase adjustment. Polarization of the crossed-undulator has observation angle dependence due to that of radiation wavelength and optical path length difference between two radiations. That limits an angular range maintaining the identical polarization state. Assuming undulator parameters for our experiment (a fundamental frequency 1.9 THz and a number of periods seven) degree of circular polarization larger than 0.9 can be obtained only in the range of 2.2 mrad, i. e. 13% of the radiation angular spread.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB038

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

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TUPRB039

Research of Coherent Edge Radiation Generated by Electron Beams Oscillating Free-Electron Lasers

FEL, electron, radiation, cavity

1772

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
H. Ohgaki, H. Zen
Kyoto University, Kyoto, Japan

Funding: JSPS KAKENHI Grant Number JP16H03912
We have studied far-infrared coherent radiation with an S-band linac at Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. We have already developed a couple of terahertz-wave sources based on coherent synchrotron radiation and coherent transition radiation*, which have been applied to spectroscopic research**. Moreover, we developed coherent edge radiation (CER) at the downstream bending magnets in the FEL sections. Because the edge radiation has an annular shape distribution characterized by the asymmetric first-order Laguerre-Gaussian mode, the CER can be extracted from an optical cavity of the FEL system without a diffraction loss of the FEL beam***. The root-mean-squared bunch length of the electron beam was evaulated by measuring the CER spectra, which was about the same level as the FEL micropulse width. Although the infrared FELs at LEBRA had a long slippage length, the CER intensity can be a guidepost enhancing the FEL power because of the existence of their correlation. In this presentation, the characteristics of the CER including correlation between the CER and the FEL will be reported.
* N. Sei et al., Jpn. J. Appl. Phys. 56, (2017) 032401.
** N. Sei et al., J. Opt. Soc. Am. B, 31, (2014) 2150.
*** N. Sei et al., Phys. Lett. A in press.

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

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TUPRB083

Status of Clara Front End Commissioning and First User Experiments

laser, vacuum, linac, diagnostics

1851

D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, R.J. Cash, H.M. Castaneda Cortes, J.A. Clarke, P.A. Corlett, L.S. Cowie, K.D. Dumbell, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.A. Griffiths, J. Henderson, F. Jackson, J.K. Jones, N.Y. Joshi, S.L. Mathisen, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, T.H. Pacey, M.D. Roper, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, E.W. Snedden, M. Surman, N. Thompson, C. Tollervey, R. Valizadeh, D.A. Walsh, T.M. Weston, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.D. Brynes, J.A. Clarke, K.D. Dumbell, D.J. Dunning, P. Goudket, F. Jackson, J.K. Jones, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, M. Surman, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R.F. Clarke, G. Cox, M.D. Hancock, J.P. Hindley, C. Hodgkinson, A. Oates, W. Smith, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
L.S. Cowie
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N.Y. Joshi, T.H. Pacey
UMAN, Manchester, United Kingdom

CLARA (Compact Linear Accelerator for Research and Applications) is a test facility for Free Electron Laser (FEL) research and other applications at STFC’s Daresbury Laboratory. The first exploitation period using CLARA Front End (FE) provided a range of beam parameters to 12 user experiments. Beam line to Beam Area 1 (BA1) was commissioned and optimised for these experiments, some involving TW laser integration. In addition to the user exploitation programme, significant advances were made to progress on machine development. This paper summarises these developments and presents the near future plan for CLARA.

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

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TUPRB086

Four X-ray Pulses within 10 ns at LCLS

laser, FEL, electron, gun

1859

F.-J. Decker, W.S. Colocho, S.H. Glenzer, A.A. Lutman, A. Miahnahri, D.F. Ratner, J.C. Sheppard, S. Vetter
SLAC, Menlo Park, California, USA

The X-Ray FEL at SLAC or LCLS delivers typically one bunch at the time. Different schemes of two bunches have been developed: Two bucket, Twin bunch, split undulator, and fresh slice. Here we discuss a four bunch or even eight bunch setup, separated by 2 RF buckets or 0.7 ns. . The demand comes from MEC (Matter in Extreme Conditions) experiments, where high-power laser beams with Joule-class energies create impulsive pressure waves compressing materials on time scales of the order of ns. Eight snapshots for a single experiment will allow measuring the compression history, structural phase transitions into new high-pressure material states, and have the potential to resolve the transition kinetics time scales.

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

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TUPRB089

Undulator Radiation Generated by a Single Electron

electron, undulator, photon, radiation

1867

A. Halavanau, Z. Huang, C. Pellegrini, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
I. Lobach
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev
Fermilab, Batavia, Illinois, USA
D. Seipt
HZDR, Dresden, Germany

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The facilities providing single electron beams are currently being commissioned at Fermilab and will be at SLAC. Recently, Fermilab’s IOTA ring routinely demonstrated circulation of a single electron at 100 MeV beam energy. Alternatively, SLAC is working on constructing LCLS-II an X-ray FEL driven by a 4 GeV SRF linac. A parasitic beamline, S30XL, is planned that will extract 4 GeV dark current from between the primary LCLS-II electron bunches. The dark current will be delivered to End Station A and can work independently of LCLS-II experiments. The dark current will be bunched at a frequency of 46 MHz while extracted current varied from single electrons to 10’s of nA. In the present paper, we estimate the feasibility of propagating single electron beams through a conventional undulator, placed in the IOTA and S30XL beamlines. We explore the possible observable effects and experimental parameters range. In addition, we focus on potential applications of such beams in systems for high fidelity quantum measurements.

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

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TUPRB090

Preliminary Considerations of Atomic Inner-Shell X-Ray Laser for Self-Seeding at LCLS-II

FEL, photon, simulation, radiation

1871

A. Halavanau, C. Pellegrini, J. Wu
SLAC, Menlo Park, California, USA
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
N. Rohringer
Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The atomic inner-shell X-ray lasing, induced by the irradiation of focused XFEL SASE pulses, was demonstrated in gases, liquid jets and solids. In this proceeding, we discuss the possible use of this concept in self-seeding scheme at LCLS-II. We provide a preliminary study of different lasing media and corresponding SASE XFEL parameters. For the case of noble gas inner-shell X-ray laser, we study the requirements for gas pressure and XFEL pulse focusing. Finally, we discuss possible designs of this system and its advantages in LCLS-II operations.

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

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TUPRB091

Study of XFEL Third Harmonic Radiation at LCLS

undulator, FEL, radiation, bunching

1875

C. Emma, M.W. Guetg, A. Halavanau, A.A. Lutman, G. Marcus, T.J. Maxwell, C. Pellegrini
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
In this paper, we focus on characterization of the nonlinear third harmonic radiation properties at Linac Coherent Light Source (LCLS). In addition, we experimentally perform third harmonic self-seeding, using diamond crystal attenuator in the hard X-ray self-seeding chicane. We discuss warm beam effects in such scheme, justifying recently proposed two bunch configuration for harmonic lasing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB091

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

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TUPRB092

Cherenkov Radiation in Periodic Wire Medium Formed by Transversely Modulated Electron Beams

radiation, electron, laser, cathode

1878

A. Halavanau
SLAC, Menlo Park, California, USA
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
E.A. Gurnevich
Belarussian State University, Scientific Research Institute of Nuclear Problems, Minsk, Belarus

Funding: Work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
We investigate the properties of Cherenkov, quasi-Cherenkov (parametric) and diffraction radiation generated in the periodic conducting wire medium by transversely modulated electron beams. Such beams were recently obtained at Argonne Wakefield Accelerator (AWA) facility using microlens array (MLA) laser shaping technique. We consider in details the case of one dimensional periodic tungsten wire structure and transverse electron beamlets separation of mm scale. We look at possible enhancements of the radiation field due to transverse periodicity of the electron beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB092

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paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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TUPRB106

Status of the Superconducting Soft X-Ray Free-Electron Laser User Facility Flash at DESY

laser, electron, operation, undulator

1909

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

FLASH, the free electron laser user facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft x-ray FEL radiation to photon experiments with different parameters at two undulator beamlines simultaneously. FLASH’s superconducting linac can produce bunch trains of up to 800 bunches within a 0.8 ms RF flat top at a repetition rate of 10 Hz. In standard operation during 2018, FLASH supplied up to 500 bunches in two bunch trains with independent fill patterns and compression schemes to each of the two beamlines. In 2018 first successful plasma accelerating experiments could be reported by the FLASHForward plasma wakefield acceleration experiment situated in a third beamline. We report on the highlights of FLASH operation in 2018/2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB106

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

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TUPTS011

Vacuum Lifetime and Surface Charge Limit Investigations Concerning High Intensity Spin-polarized Photoinjectors

cathode, electron, vacuum, laser

1954

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

Funding: DFG excellence initiative PRISMA+, Bundesministerium für Bildung und Forschung "Verbundforschung FKZ 05K16UMA"
The Small Thermalized Electron Source at Mainz (STEAM) is a dc photoemission source. It is designed to operate at up to 200kV bias voltage with an accelerating field of up to 5 MV/m at the cathode surface. In several experiments, the properties of GaAs operating under the conditions of spin-polarized photoemission were investigated. Its performance, quantum efficiency lifetime and surface charge limit observations for bulk-GaAs will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS011

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paper received ※ 29 April 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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TUPTS012

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

laser, emittance, simulation, cathode

1958

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

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

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

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

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TUPTS029

The New Eddy Current type Septum Magnets for Upgrading of Fast Extraction in Main Ring of J-PARC

operation, septum, extraction, feedback

1997

T. Shibata, K. Ishii, H. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
HUST, Wuhan, People’s Republic of China
K. Hamano
Nichicon (Kusatsu) Corporation, Shiga, Japan

The J-PARC Main Ring (MR) is working on imporved beam to 750 kW by shorting the repetition period from 2.48 s to 1.3 s which we call 1Hz operation. The septum magnets for fast extraction in MR will be improved to the new septum magnets which can operate 1Hz. The new magnets will be installed to MR in 2021. In this poster we will report about the new low field septum magnet for the fast extraction. The present septum magnets are conventional type. Therefore, we have problem in durability of thin septum coil by its magnetic vibration, and large leakage field at the exit of the circulating beam duct. The new septum magnets are eddy current type. The eddy current type does not have septum coil, but has a thin septum plate. We can expect that there is no problem in durability of septum coil, and leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of fundamental and 3rd harmonic sin-wave pulse. We can expect that the flatness and reproducibility of flat top current can be improved. We confirmed that 1Hz operation and high accuracy of its output current and magnetic field with the new septum magnet system. We had some problem in unexpected instability of output current. In this report we also summarize the measure against the instabillity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS029

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS034

Development of Low Inductance Circuit for Radially Symmetric Circuit

impedance, kicker, high-voltage, operation

2013

T. Takayanagi, K. Horino, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan

Radiation symmetric type circuits using semiconductors of SIC-MOSFETs, one of next generation semiconductors, are composed of circuits in which many semiconductor switches are multiplexed in series and in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or level change. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the actual measurement in the actual test and present the verification result of the developed circular ring structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS034

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

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TUPTS070

Systematic Benchmarking of a Planar (N)UNCD Field Emission Cathode

cathode, gun, electron, ECR

2083

J.H. Shao, M.E. Conde, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.V. Baryshev, M.S. Schneider
Michigan State University, East Lansing, Michigan, USA
G. Chen
IIT, Chicago, Illinois, USA
K. Kovi
Euclid TechLabs, LLC, Solon, Ohio, USA
L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Planar nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, is a unique and attractive field emission source because of the capability to generate high charge beam, the simplicity of production without shaped emitters, and the ease of handling with moderate vacuum requirement. In the presented study using an L-band normal conducting single-cell rf gun, a (N)UNCD cathode has been conditioned to 42 MV/m with a well-controlled manner and reached a maximum charge of 15 nC and an average emission current of 6~mA during a 2.5 us emission period. The systematic study of emission properties during the rf conditioning process illustrates the tunability of (N)UNCD in a wide range of surface gradients. This research demonstrates the versatility of (N)UNCD cathode which could enable multiple designs of field emission rf injector for industrial and scientific applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS070

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

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TUPTS073

Analysis of Electron Beam Divergence in Diamond Field Emitter Array Cathodes

cathode, focusing, simulation, electron

2090

D. Kim, H.L. Andrews, R.L. Fleming, C. Huang, J.W. Lewellen, K.E. Nichols, V.N. Pavlenko, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
B.K. Choi
Cheju Halla University, Jeju-si, Republic of Korea

Funding: Los Alamos National Laboratory (LANL) Laboratory Directed Research and Development (LDRD) program (Contract DE-AC52-06NA25396) and Sandia National Laboratories (Contract DE-NA-0003525).
At Los Alamos National Laboratory (LANL), we have recently established a capability to fabricate diamond array cathodes for electron beam sources. Our fabricated diamond field emitter arrays (DFEAs) are the arrays of micrometer-scale diamond pyramids with nanometer-scale sharp tips and produce high per-tip current (> 15 μA per-tip) in DC testing. For the beam divergence measurements, we designed and assembled a test stand consisting of a DFEA cathode, a mesh aperture of 0.375-inch for an anode, and AZO (ZnO:Al2O3) screen coated on a sapphire substrate for beam visualization. A negative voltage of about 40 kV is applied to the cathode, and the mesh and the screen are kept at ground. We measure a size of the electron beam on the AZO screen at different mesh to screen distances at a fixed cathode-mesh gap in order to calculate the beam divergence angles. We also perform the beam dynamics simulations with Computer Simulation Technology (CST) Studio and General Particle Tracer (GPT) using a single pyramidal shape with a nanowire tip model. In this presentation, the measured experimental results of the beam divergences will be compared to the beam dynamic simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS073

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

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TUPTS077

Design of a High Gradient THz-Driven Electron Gun

electron, gun, acceleration, FEL

2098

S.M. Lewis, V.A. Dolgashev, A.A. Haase, E.A. Nanni, M.A.K. Othman, A.V. Sy, S.G. Tantawi
SLAC, Menlo Park, California, USA
D. Kim, E.I. Simakov
LANL, Los Alamos, New Mexico, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515. This work was also supported by NSF grants PHY-1734015.
We present the design of a high-gradient electron gun. The goal of this gun is to generate relativistic electrons using GV/m accelerating fields. The initial design is a standing-wave field-emission gun operating in the pi-mode with a cavity frequency of 110.08 GHz. A pulsed 110 GHz gyrotron oscillator will be used to drive the structure with power coupled in through a TM01 circular waveguide mode. The gun is machined in two halves which are bonded. This prototype will be used to characterize the electron beam and study RF breakdown at 110 GHz.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS077

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

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TUPTS078

Coherent Electron Cooling (CeC) Experiment at RHIC: Status and Plans

electron, FEL, SRF, simulation

2101

V. Litvinenko, K. Mihara
Stony Brook University, Stony Brook, USA
Z. Altinbas, J.C. Brutus, A. Di Lieto, D.M. Gassner, T. Hayes, P. Inacker, J.P. Jamilkowski, Y.C. Jing, R. Kellermann, J. Ma, G.J. Mahler, M. Mapes, R.J. Michnoff, T.A. Miller, M.G. Minty, G. Narayan, M.C. Paniccia, D. Phillips, I. Pinayev, S.K. Seberg, F. Severino, J. Skaritka, L. Smart, K.S. Smith, Z. Sorrell, R. Than, J.E. Tuozzolo, E. Wang, G. Wang, Y.H. Wu, B.P. Xiao, T. Xin, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA
K. Shih
SBU, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and NSF Grant No. PHY-141525
We will present currents status of the CeC experiment at RHIC and discuss plans for future. Special focus will be given to unexpected experimental results obtained during RHIC Run 18 and discovery of a previously unknown type of microwave instability. We called this new phenomenon micro-bunching Plasma Cascade Instability (PCI). Our plan for future experiments includes suppressing this instability in the CeC accelerator and using it as a broad-band amplifier in the CeC system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS078

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS084

Performances of Silicon-Based Field-Emission Cathodes Coated with UltraNano Crystalline Diamond

cathode, electron, vacuum, simulation

2117

O. Mohsen, V. Korampally, A. Lueangaramwong, P. Piot, V. Valluri
Northern Illinois University, DeKalb, Illinois, USA
R. Divan, A.V. Sumant
Argonne National Laboratory, Argonne, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: Work supported by NSF grant PHY-1535401 and DOE award DE-SC0018367 with NIU
Field-emission electron sources have been considered as possible candidates for the production of bright or high-current electron bunches. In this paper, we report on the experimental characterization of silicon-based field-emitter arrays (FEA) in a DC high voltage gap. The silicon cathodes are produced via a simple self-assembling process. The measurement reported in this paper especially compares the field-emission properties of a nanostructured and planar diamond-coated Si-based cathode.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS084

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paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS089

Observations of the Femtosecond Laser-Induced Emission From the Diamond Field Emitter Tips

laser, electron, cathode, photon

2130

E.I. Simakov, H.L. Andrews, R.L. Fleming, D. Kim, V.N. Pavlenko
LANL, Los Alamos, New Mexico, USA
D.S. Black, K.J. Leedle
Stanford University, Stanford, California, USA

Funding: Los Alamos National Laboratory LDRD Program
We present the results of experimental observation of emission from single diamond field emitter tips when triggered by an ultra-short laser pulse. Diamond field emitter array (DFEA) cathodes were originally proposed for applications that require large current densities. DFEAs represent periodic arrays of diamond pyramids with micron-size dimensions and tips with diameters of the order of tens of nanometers. DFEAs are known to produce significant currents in field emission regime under direct current (DC) fields and in radio-frequency (RF) guns. It has been proposed that single diamond tip emitters can be employed for production of small tightly focused electron beams for dielectric laser accelerators (DLAs) that accelerate particles using the energy of light produced by infrared lasers. To generate short electron bunches required by DLAs diamond pyramids may be triggered with a laser. We have recently observed emission produced by a single diamond pyramid when triggered by a laser at different wavelengths from 256 nm to 2020 nm. We have conducted studies with the goal to understand mechanism of the emission. We clearly observed the change in emission mechanism when the wavelength changed from 256 nm to 512 nm. We believe that while the emission at 256 nm is a clear photoemission, the emission at longer wavelengths is likely the field emission caused by intense electric fields of the laser.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS089

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

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TUPTS090

Experimental Results of Dense Array Diamond Field Emitters in RF Gun

cathode, gun, solenoid, wakefield

2134

K.E. Nichols, H.L. Andrews, D. Kim, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S.P. Antipov
Euclid Beamlabs LLC, Bolingbrook, USA
G. Chen
IIT, Chicago, Illinois, USA
M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.F. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA

We present experimental emission results from arrays of diamond field emitter tips operating in an RF gun at the Argonne Cathode Test-stand. Results from various arrays will be presented with different spacing between array elements. Very high charge densities were produced at various field gradients. The maximum field gradient for a particular geometry was discovered and break-down effects will be presented. Cathode lifetime was preliminarily studied. Further experiments are being planned and work on the cathode design optimization to produce higher quality beams will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS090

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

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TUPTS091

Physics of Electron Beam Generation and Dynamics From Diamond Field Emitter Arrays

electron, simulation, cathode, ECR

2137

C. Huang, H.L. Andrews, R.C. Baker, R.L. Fleming, D. Kim, T.J. Kwan, V.N. Pavlenko, A. Piryatinski, E.I. Simakov
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the LDRD program at Los Alamos National Laboratory
Many applications such as compact accelerators and electron microscopy demand high brightness electron beams with small beam size and low emittance. Electric-field-assisted diamond emitters manufactured from semiconductor processes are strong candidates for cathodes in such sources. The micro-scale pyramid structure of the emitter has the desirable attribute of significant field enhancement at the sharp interfaces (apex and edges) to facilitate electron emission. We use the LSP particle-in-cell code to simulate the diamond emitter in a diode setup and obtain the beam size and divergence. An empirical fit of the fields around the apex is extracted for detail study. The trend of the beam divergence observed in the simulation is further corroborated using electron’s trajectory in the empirical field model.

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

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TUPTS108

Numerical Simulations of RHIC FY17 Spin Flipper Experiments

simulation, resonance, dipole, polarization

2174

P. Adams, H. Huang, J. Kewisch, C. Liu, F. Méot, P. Oddo, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, T. Roser
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Spin flipper experiments during RHIC Run 17 have demonstrated the 97% effectiveness of polarization sign reversal during stores. Zgoubi numerical simulations were setup to reproduce the experimental conditions. A very good agreement between the experimental measurements and simulation results was achieved at 23.8GeV, thus the simulations are being used to help optimize the various Spin Flipper parameters. The ultimate goal for these simulations is to serve as guidance towards a perfect flip at high energies to allow a routine Spin Flipper use during physics runs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS108

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

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TUPTS114

Electron Stimulated Desorption from Cryogenic NEG-Coated Surfaces

vacuum, electron, cryogenics, site

2193

R. Sirvinskaite, M.D. Cropper
Loughborough University, Loughborough, Leicestershire, United Kingdom
A.N. Hannah, O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Non-Evaporable Getter (NEG) coating has been used for years in many particle accelerators due to its advantages like evenly distributed pumping speed, low thermal outgassing, and low photon, electron and ion stimulated desorption yields. Although NEG coating has been tested at room temperatures intensively, there is little data on its behaviour at cryogenic temperatures. Tests in this environment are important for the Future Circular Collider (FCC) study and other accelerator facilities where the operational conditions of the beam screen are restricted to cryogenic temperatures. This work will provide some preliminary results on NEG properties at low temperatures, e.g. pumping speed and capacity, as well as its behaviour under electron bombardment, where electron stimulated desorption (ESD) yields will be calculated. The ternary Ti-Zr-V coating, deposited with dense and columnar structure, will be the first material to be tested at cryogenic temperatures in ASTeC Daresbury laboratory. The results were compared with the ones obtained at room temperature, offering an insight into the behaviour of NEG-coated cryogenic chambers when beam-induced effects are present.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS114

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

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WEXXPLM1

Amplified Emission of a Soft-X Ray Free-Electron Laser Based on Echo-Enabled Harmonic Generation

FEL, laser, electron, free-electron-laser

2230

E. Allaria, L. Badano, G. De Ninno, S. Di Mitri, B. Diviacco, W.M. Fawley, N.S. Mirian, G. Penco, P. Rebernik Ribič, S. Spampinati, C. Spezzani, M. Trovò
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno
University of Nova Gorica, Nova Gorica, Slovenia
E. Ferrari, E. Prat
PSI, Villigen PSI, Switzerland
D. Garzella
CEA, Gif-sur-Yvette, France
V. Grattoni
DESY, Hamburg, Germany
E. Hemsing
SLAC, Menlo Park, California, USA
M.A. Pop
MAX IV Laboratory, Lund University, Lund, Sweden
E. Roussel
PhLAM/CERLA, Villeneuve d’Ascq, France
D. Xiang
Shanghai Jiao Tong University, Shanghai, People’s Republic of China

We report the first evidence of substantial gain in a soft-X ray Free Electron Laser (FEL) based on Echo-Enabled Harmonic Generation (EEHG). The experiment was focused on harmonics 36 (~7.3nm) and 45 (5.8 nm) and clearly demonstrated the expected EEHG capability of generating powerful and coherent FEL pulses, with strongly reduced sensitivity to electron-beam fluctuations. The experiment was carried out at FERMI, the seeded FEL user facility at Elettra-Sincrotrone Trieste.

Slides WEXXPLM1 [11.410 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLM1

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paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEXXPLS2

Accelerator Vacuum Windows: A Review of Past Research and a Strategy for the Development of a New Design for Improved Safety and Longevity for Particle Accelerators

vacuum, Windows, radiation, scattering

2237

C.R. Ader, M.L. Alvarez, J.S. Batko, R. Campos, M.W. McGee, A.C. Watts
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
Vacuum window research continues at Fermilab and this paper will examine cost effective, consistent designs which can have a significant impact on accelerator laboratories in terms of safety and cost. Issues such as the design, materials, analysis, testing and fabrication are addressed, including beam scattering and materials cost-benefit analysis and examining potential material substitutes for beryllium. A previous research paper has examined current fabrication and design techniques and also failure modes at Fermi, and this paper focuses on emerging and novel technologies for vacuum window fabrication. Many different paths have been taken by High Energy Physics (HEP) Laboratories throughout the world with varying success. The history of vacuum window development is extensive and not well defined, and a matrix of the research already completed on materials and joint design for vacuum windows will be shown. This report finally includes a treatise for vacuum window technology and a view towards emerging designs and materials and discusses future advances of research such as fabrication techniques including additive manufacturing and ultrasonic welding. Further exploration into these would prove beneficial to developing vacuum windows that are safer and stronger while being more transparent to the beam.

Slides WEXXPLS2 [3.139 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLS2

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

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WEXXPLS3

Is it Possible to Use Additive Manufacturing for Accelerator UHV Beam Pipes?

electron, vacuum, laser, ECR

2240

G. Sattonnay, M. Alves, S. Bilgen, B.J. Bonnis, A. Gonnin, D. Grasset, S. Jenzer, F. Letellier-Cohen, B. Mercier, E. Mistretta
LAL, Orsay, France
F. Brisset
ICMMO, Orsay, France

Funding: Work supported by a grant from IN2P3/CNRS, program I3D metal
Recently, additive manufacturing (AM) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. AM by selective laser melting (SLM) is an advanced manufacturing process which uses lasers to melt metal powders one layer at a time to produce final 3D components. This technology could be also used to make Ultra High Vacuum components. Therefore, we investigated in this work the reproducibility of AM 316L stainless steel properties for different specimen supplied by several manufacturers with the same SLM process. Clearly, the microstructure and therefore the mechanical properties of the investigated AM samples are different as a function of manufacturers: indeed, they are largely influenced by processing parameters, which produces heterogeneous and anisotropic microstructures that differ from traditional wrought counterparts. Samples were also submitted to bake cycles at high temperature, in order to check the structural stability of material properties after heat treatments. The outgassing rates and the secondary emission yield of vacuum components constructed from AM 316L were also measured. Finally, the possibility to use AM for accelerator beam pipes will be discussed.

Slides WEXXPLS3 [9.009 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLS3

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

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WEYYPLM2

The 2018 Heavy-Ion Run of the LHC

luminosity, heavy-ion, optics, proton

2258

J.M. Jowett, C. Bahamonde Castro, W. Bartmann, C. Bracco, R. Bruce, J.M. Coello de Portugal, J. Dilly, S.D. Fartoukh, E. Fol, N. Fuster-Martínez, A. Garcia-Tabares, M. Hofer, E.B. Holzer, M.A. Jebramcik, J. Keintzel, A. Lechner, E.H. Maclean, L. Malina, T. Medvedeva, A. Mereghetti, T.H.B. Persson, B.Aa. Petersen, S. Redaelli, B. Salvachua, M. Schaumann, C. Schwick, M. Solfaroli, M.L. Spitznagel, H. Timko, R. Tomás, A. Wegscheider, J. Wenninger, D. Wollmann
CERN, Geneva, Switzerland
D. Mirarchi
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom

The fourth one-month Pb-Pb collision run brought LHC Run 2 to an end in December 2018. Following the tendency to reduce dependence on the configuration of the preceding proton run, a completely new optics cycle with the strongest ever focussing at the ALICE and LHCb experiments was designed and rapidly implemented, demonstrating the maturity of the collider’s operating modes. Beam-loss monitor thresholds were carefully adjusted to provide optimal protection from the multiple loss mechanisms in heavy-ion operation. A switch from a basic bunch-spacing of 100 ns to 75 ns was made as the beam became available from the injector chain. A new record luminosity, 6 times the original design and close to the operating value proposed for HL-LHC, provided validation of the strategy for mitigating quenches due to bound-free pair production (BFPP) at the interaction points of the ATLAS and CMS experiments. Most of the beam parameters of the HL-LHC Pb-Pb upgrade were attained during this run and the integrated luminosity goals for the first 10 years of LHC operation were substantially exceeded.

Slides WEYYPLM2 [10.884 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLM2

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paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEYYPLM3

First Results of the Compensation of the Beam-Beam Effect with DC Wires in the LHC

beam-beam-effects, operation, collider, simulation

2262

G. Sterbini, D. Amorim, H. Bartosik, A. Bertarelli, R. Bruce, X. Buffat, F. Carra, L.R. Carver, G. Cattenoz, E. Effinger, S.D. Fartoukh, N. Fuster-Martínez, M. Gąsior, M. Gonzalez-Berges, A.A. Gorzawski, G.H. Hemelsoet, M. Hostettler, G. Iadarola, O.R. Jones, N. Karastathis, S. Kostoglou, I. Lamas Garcia, T.E. Levens, L.E. Medina Medrano, D. Mirarchi, J. Olexa, S. Papadopoulou, Y. Papaphilippou, D. Pellegrini, M. Pojer, L. Ponce, A. Poyet, S. Redaelli, A. Rossi, B. Salvachua, H. Schmickler, F. Schmidt, K. Skoufaris, M. Solfaroli, R. Tomás, G. Trad, D. Valuch, C. Xu, C. Zamantzas, P. Zisopoulos
CERN, Geneva, Switzerland
D. Amorim
Grenoble-INP Phelma, Grenoble, France
M. Fitterer, A. Valishev
Fermilab, Batavia, Illinois, USA
D. Kaltchev
TRIUMF, Vancouver, Canada
S. Kostoglou
National Technical University of Athens, Zografou, Greece
A.E. Levichev
BINP SB RAS, Novosibirsk, Russia
A. Poyet
Université Grenoble Alpes, Grenoble, France

The compensation of the long-range beam-beam interactions using DC wires is presently under study as an option for enhancing the machine performance in the frame of the High-Luminosity LHC project (HL-LHC). The original idea dates back more than 15 years. After the installation of four wire prototypes in the LHC in 2018, a successful experimental campaign was performed during the last months. The experimental setup and the main results are reported in this paper.

Slides WEYYPLM3 [6.371 MB]

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paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEYYPLS1

Muon G-2: An Interplay between Beam Dynamics and a Muon Decay Experiment at the Precision Frontier

storage-ring, proton, detector, injection

2266

M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Funding: This work has been partially funded by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Muon g-2 Experiment at Fermilab (E989) will use the higher proton flux delivered by the Fermilab accelerator complex and improvements to the experimental apparatus to measure the anomalous magnetic moment of the muon to unprecedented precision. In addition to the increased statistics beyond the most recent measurement, the experiment relies on detailed understanding of the beam dynamics in the experiment’s storage ring as well as the incoming muon beam properties for proper assessments of systematic errors in the data analysis. Modeling and measurements of beam and storage ring properties, from proton targeting to muon storage, produce a unique unification of particle beam physics with a high energy physics experiment. Here the beam dynamics issues and analysis techniques essential to the g-2 experiment are presented and discussed.

Slides WEYYPLS1 [12.990 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLS1

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

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WEYYPLS2

First Experimental Measurements of the Caustic Nature of Trajectories in Bunch Compressors

linac, electron, FEL, sextupole

2270

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
J. Björklund Svensson
Lund University, Lund, Sweden
A. Latina
CERN, Geneva, Switzerland
S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

Theoretical advancements describing density perturbations in accelerated charge particle beams, known as caustics, has been recently developed * This proceeding describes the first experimental measurements of the caustic nature of charged particle trajectories in a particle accelerator. Caustics by their nature are discontinuities that result from small continuous perturbations of an input. Under certain conditions, small density modulations will reliably produce striking changes in the corresponding output current profile. These current modulations can shift alone the bunch with varying higher-order longitudinal dispersion. The MAX IV linac double-bend achromats provide the perfect test bed for experimentally verifying how the caustic lines evolve. The natural amplification of small perturbations makes caustics an attractive diagnostic tool, and effective tool for characterise the bunch compressors. This approach also allows us to modify and improve the longitudinal charge profile, removing current spikes or creating tailor shaped current profiles.
* T.K.Charles et. al. Phys. Rev. Accel. Beams 19, 104402

Slides WEYYPLS2 [5.402 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLS2

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

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WEZPLS2

High Transformer Ratio Plasma Wakefield Acceleration Driven by Photocathode Laser Shaped Electron Bunches

plasma, wakefield, laser, acceleration

2286

G. Loisch
DESY Zeuthen, Zeuthen, Germany

Beam driven wakefield acceleration (PWFA) schemes in plasmas are among the most promising candidates for novel, compact accelerators. Several aspects of PWFA are under investigation at the Photoinjector Test facility at DESY in Zeuthen (PITZ). One of the main characteristics of these accelerators is the ratio between field strength usable for acceleration and decelerating field strength in the driver bunch, the so called transformer ratio. To reach high transformer ratios usually shaped bunches, e.g. with ramped current profiles are employed as drivers. The so-called self-modulation instability, which causes transverse modulation of a bunch longer than the plasma wavelength, is proposed as a means of supplying short driver bunches for proton-driven PWFA. This talk will give an overview on experimental results in these two aspects of PWFA at PITZ with a focus on the production of electron bunches enabling high transformer ratio acceleration by shaping the photocathode laser pulses of a photoinjector and the demonstration of high transformer ratio PWFA. Simulations and further developments on the shaping techniques, allowing highly flexible electron bunches for future plasma wakefield accelerators are also presented.

Slides WEZPLS2 [5.172 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZPLS2

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

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WEPMP005

Beam Line Optimization Using Derivative-Free Algorithms

target, heavy-ion, site, interface

2307

S. Appel, S. Reimann
GSI, Darmstadt, Germany

The present study focuses on the beam line optimization from the heavy-ion synchrotron SIS18 to the HADES experiment. BOBYQA (Bound Optimization BY Quadratic Approximation) solves bound constrained optimization problems without using derivatives of the objective function. The Bayesian optimization is an other strategy for global optimization of costly, noisy functions without using derivatives. A python programming interface to MADX allow the use of the python implementation of BOBYQA and Bayesian method. This gave the possibility to use tracking simulation with MADX to determine the loss budget for each lattice setting during the optimization and compare both optimization methods.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP005

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

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WEPMP007

Current Status of Slow Extraction from J-PARC Main Ring

extraction, operation, proton, radiation

2311

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

A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP007

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paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP008

A Consideration on the Transfer Function Between RQ Field and Slow Extraction Spill in the Main Ring of J-Parc

extraction, feedback, operation, controls

2315

K. Okamura, Y. Arakaki, S. Murasugi, R. Muto, Y. Shirakabe, M. Tomizawa, E. Yanaoka
KEK, Ibaraki, Japan
T. Kimura
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer reso-nant extraction and delivered to the hadron experimental facility. Increasing the duty of beam spill is one of the important issues in the slow extraction system. In the MR, the spill feedback system utilizing a digital signal processor (DSP) combined with EQ and RQ magnet is used to smooth the spill, where EQ defines a rough out-line of the slow extraction shape and RQ is used for the ripple cancelling. In this study, frequency domain charac-teristics between the current of RQ magnet and the beam spill was investigated by driving the RQ magnet with sinusoidal current, so that the transfer function from the current of RQ magnet to the spill signal is delivered.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP008

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

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WEPMP027

Update on Beam Transfer Line Design for the SPS Beam Dump Facility

target, proton, quadrupole, extraction

2375

Y. Dutheil, J. Bauche, L.A. Dougherty, M.A. Fraser, B. Goddard, C. Heßler, V. Kain, J. Kurdej, J.A. Uythoven, F.M. Velotti
CERN, Geneva, Switzerland

The SPS Beam Dump Facility (BDF) being studied as part of the Physics Beyond Colliders (PBC) CERN project has recently reached an important milestone with the completion of the comprehensive feasibility study. The BDF is a proposed fixed target facility to be installed in the SPS North Area, to accommodate experiments such as SHiP (Search for Hidden Particles), which is most notably aiming at studying hidden sector particles. This experiment requires a high intensity slowly extracted 400 GeV proton beam with 4·10¹³ protons per 1 s spill to achieve 4·10¹⁹ protons on target per year. The extraction and transport scheme will make use of the first 600 m of the existing North Area extraction line. This contribution presents the status of the design work of the new transfer line and discusses the challenges identified. Aperture studies and failure scenarios are treated and the results discussed. In particular, interlock systems aiming at protecting critical components against the uncontrolled loss of the high energy proton beam are considered. We also present the latest results and implications of the design of a new laminated Lambertson splitter magnet to provide fast switching between the current North Area experiments and the BDF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP027

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

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WEPMP028

Crystal for Slow Extraction Loss-Reduction of the SPS Electrostatic Septum

extraction, proton, ECR, alignment

2379

L.S. Esposito, P. Bestman, M.E.J. Butcher, M. Calviani, M. Di Castro, M. Donzé, M.A. Fraser, M. Garattini, Y. Gavrikov, S.S. Gilardoni, B. Goddard, V. Kain, J. Lendaro, A. Masi, M. Pari, J. Prieto, R. Rossi, W. Scandale, R. Seidenbinder, P. Serrano Galvez, L.S. Stoel, F.M. Velotti, V. Zhovkovska
CERN, Geneva, Switzerland
F.M. Addesa, F. Iacoangeli
INFN-Roma, Roma, Italy
A.G. Afonin, Y.A. Chesnokov, A.A. Durum, V.A. Maisheev, Yu.E. Sandomirskiy, A.A. Yanovich
IHEP, Moscow Region, Russia
J.E. Borg, M. Garattini, G. Hall, T. James, M. Pesaresi
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
A.S. Denisov, Y. Gavrikov, Yu.M. Ivanov, M.A. Koznov, L.G. Malyarenko, V. Skorobogatov
PNPI, Gatchina, Leningrad District, Russia
F. Galluccio
INFN-Napoli, Napoli, Italy
A.D. Kovalenko, A.M. Taratin
JINR, Dubna, Moscow Region, Russia
F. Murtas
INFN/LNF, Frascati, Italy
A. Natochii
LAL, Orsay, France

The use of a bent crystal was investigated in order to reduce the losses at the CERN Super Proton Synchrotron (SPS) electrostatic septa (ZS) during the slow extraction of 400 GeV protons toward the North Area. The crystal, installed a few meters upstream the ZS, bends protons that would otherwise impinge on the ZS wires. Since particle deflection with good efficiency is achieved only when the crystal lattice is aligned within ~10 urad to the trajectory of the particles (at p = 400 GeV/c), a compact goniometer was built to allow the correct angular alignment of the crystal with respect to the incoming beam with a precision of few urad. In this paper, we report on the crystal features measured during a dedicated beam test by the UA9 experimental installation in the CERN H8 beam line. Details of the goniometer and its installation are also reported. The first results achieved during dedicated Machine Development (MD) sessions are finally presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP028

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

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WEPMP029

Systematic Optics Studies for the Commissioning of the AWAKE Beamline

electron, optics, plasma, quadrupole

2383

C. Bracco, B. Goddard, I. Gorgisyan, M. Turner, F.M. Velotti, L. Verra
CERN, Geneva, Switzerland
M. Aiba
PSI, Villigen PSI, Switzerland

The commissioning of the AWAKE electron beam line was successfully completed in 2018. Despite a modest length of about 15 m, this low-energy line is quite complex and several iterations were needed before finding satisfactory agreement between the model and the measurements. The work allowed to precisely predict the size and positioning of the electron beam at the merging point with the protons inside the plasma cell, where no direct measurement is possible. All the key aspects and corrections which had to be included in the model, precautions and systematic checks to apply for the correct setup of the line are presented. The sensitivity of the ~18 MeV electron beam to various perturbations, like different initial optics parameters and beam conditions, energy jitter and drifts, earth’s magnetic field etc., is described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP029

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

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WEPMP032

Tracking Simulations of Shadowing Electrostatic Septum Wires by Means of Bent Crystals

simulation, extraction, septum, optics

2395

F.M. Velotti, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel
CERN, Meyrin, Switzerland

The Super Proton Synchrotron (SPS) slow extraction is a third integer resonant extraction and hence suffers from high losses at the electrostatic septum (ZS). This is one of the main limiting factors for the maximum number of Protons On Target (POT) deliverable from the SPS to the North Area (NA). A concept to significantly reduce the extraction losses via shadowing of the electrostatic septum wires using an upstream bent crystal has been proposed in *, predicting a loss reduction of up to 50% for the prototype system installed in 2018. Following the successful experimental demonstration of the concept with beam **, detailed tracking simulations have been performed to fully understand the results obtained. Further insights, such as the effective ZS width and its alignment, could be deduced by exploiting the response of the extraction loss as a function of the two degrees of freedom of the crystal (position and angle). In this paper, the beam dynamics simulations are discussed together with the implementation of the bent crystal into the simulation framework. A comparison with measurements is presented before proposals for new configurations and parameters are discussed.
* F.M. Velotti, et al., "Reduction of Resonant Slow Extraction Losses…", IPAC’18.
** F.M. Velotti, M.A. Fraser, et al., "Experimental SPS Slow Extraction Loss Reduction…", this conf.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP032

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

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WEPMP035

Model and Measurements of CERN-SPS Slow Extraction Spill Re-Shaping - the Burst Mode Slow Extraction

extraction, operation, sextupole, simulation

2406

M. Pari, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland

The ENUBET ("Enhanced NeUtrino BEams from kaon Tagging") Project aims at reaching a new level of precision of the short-baseline neutrino cross section measurement by using an instrumented decay tunnel. The North Area (NA) experimental facility of the Super Proton Synchrotron (SPS) offers the required infrastructure for the experiment. A new slow extraction type, consisting of bursts of many consecutive millisecond spills within one macro spill, has been modeled and tested for the ENUBET Project. The burst-mode slow extraction has been tested for the first time at CERN-SPS, and MADX simulations of the process have been developed. In this paper the experimental results obtained during the test campaign are presented along with the results of the quality of the produced spill and comparing it with predictions from simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP035

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

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WEPMP049

Simulations of Beam Shaping for Dark Matter Experiments at LCLS-II

electron, FEL, optics, quadrupole

2443

Y.M. Nosochkov, C. Hast, T.W. Markiewicz, L.Y. Nicolas, T.O. Raubenheimer, M. Santana-Leitner
SLAC, Menlo Park, California, USA

Funding: * Work supported by the U.S. DOE Contract DE-AC02-76SF00515.
A new transfer beamline, called S30XL, and an experimental facility are proposed to be built at SLAC, taking advantage of the LCLS-II free electron laser (FEL) under construction. The S30XL will operate parasitically to the FEL by extracting the unused low intensity 4-GeV LCLS-II bunches into the existing A-line and the End Station-A (ESA). This provides a unique capability of multi-GeV nearly continuous electron beam for a variety of HEP experiments, in particular the dark matter search experiments. The latter require a very low beam current ranging from pA to micro-A, as well as a large beam spot at the detector. The necessary beam shaping will be performed using spoilers and collimators in the A-line, and by optimizing the optics. FLUKA and elegant codes are used to generate and track the beam into the ESA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP049

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

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WEPMP053

Operational Results of Simultaneous Four-Beam Delivery at Jefferson Lab

laser, operation, cavity, gun

2454

R. Kazimi, A. Freyberger, J.M. Grames, J. Hansknecht, A.S. Hofler, T.E. Plawski, M. Poelker, M.F. Spata, Y.W. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A concept for simultaneous beam delivery to all four CEBAF experimental halls from a single injector and a single main accelerator for the 12 GeV era was proposed in 2012. The original 12 GeV beam delivery plan was for a maximum of three experimental halls at a time as in the 6 GeV era. Therefore, the new concept increases the po-tential beam time for the experiments up to 33%. This change, although a major improvement in operational capabilities, required only limited modifications to the existing machine. The modifications were mainly timing and pattern changes to the beams in the injector, adding a fourth laser to the photo-cathode gun, and the addition of new RF separators to the highest pass of CEBAF. These changes are now complete and, for the first time, the full system is operating, producing four simultaneous beams through the accelerator to four different destinations. In this paper, in addition to presenting the results of the full system commissioning, we will discuss important details about the new configuration plus some of our operational challenges.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP053

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

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WEPGW006

Development of a Beam Loss Monitor and Transverse Beam Dynamics Studies at ARRONAX C70XP Cyclotron

cyclotron, radiation, operation, quadrupole

2470

A. Sengar, X. Goiziou, F. Gomez Serito, C. Koumeir, F. Poirier
Cyclotron ARRONAX, Saint-Herblain, France
F. Haddad
SUBATECH, Nantes, France

Funding: "Investissements d’Avenir", Equipex Arronax-Plus, Institute of Nuclear and Particle Physics from the National Scientific Research center (CNRS) and the Regional Council of Pays de la Loire, France.
The ARRONAX Interest Public Group uses a multi-particle, high energy and high intensity industrial accelerator which has several beamlines used for various purposes. For improvement of operations, ARRONAX has foster and installed robust air-based Beam Loss Monitors (BLMs) outside the beam pipes. BLMs consist of four active detecting plates and are integrated within the experimental physics and industrial control system (EPICS) monitoring and data acquisition system. Each BLM has been tested for the pre-commissioning phase with beams at low intensity (600pA to 6nA on target). Comparative studies and selection of the BLMs has led to their installation at high intensity beam lines. BLMs are now used in beam dynamics studies to investigate transverse characteristics while in regular operation. They support present and future operations extension foreseen at ARRONAX. The results from experimental studies on BLMs at low beam intensity and status of beam dynamics studies at high intensity (A) are presented here. Keywords: BLM, beam dynamics, EPICS, Gas ionization detector, cyclotron, proton.
*F. Poirier, S. Girault, STUDIES AND UPGRADES ON THE C70 CYCLOTRON ARRONAX, Proceedings of Cyclotrons 2016, Zurich, Switzerland

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

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WEPGW007

Progress of the Machine Control Upgrade at COSY/JüLICH

controls, EPICS, operation, quadrupole

2473

V. Kamerdzhiev, I. Bekman, C. Böhme, R. Gebel, B. Lorentz, P. Niedermayer, M. Simon, M. Thelen
FZJ, Jülich, Germany
R. Modic, ’. Oven
Cosylab, Ljubljana, Slovenia

The Cooler Synchrotron COSY operated at the Research Center Jülich is undergoing staged machine control upgrades driven by the requirements of the JEDI (Jülich Electric Dipole moment Investigations) collaboration. The upgrades aim towards better beam control e.g. beam orbit, tune, and chromaticity control improvements. A better orbit control was achieved through the upgrade of BPM electronics and migration from initial Tcl/Tk based control system to Control System Studio (CSS) utilizing EPICS. Currently, a design for improved beam tune control is in development. The main part of work is the transition towards a faster and less restrictive magnet control. It further includes improved tune measurement tools as well as the migration of control for quadrupole magnets to EPICS. Ultimately the control of all systems should be centralized around EPICS to enable ease of operation, automation, setup of services, etc. The decision path, technical details of the upgrade and performance of the upgraded sub-systems are presented. We also showcase how the COSY team’s physics and research goals are complemented by Cosylab’s technical design and implementation to form a synergetic collaboration.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW007

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

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WEPGW008

Fiber Beam Loss Monitors at MAMI

beam-losses, detector, FPGA, electron

2477

M. Dehn, P. Achenbach, I. Beltschikow, O. Corell, P. Gülker, W. Lauth, M. Mauch
IKP, Mainz, Germany

Funding: Work supported by DFG (CRC 1044) and the German federal state of Rhineland-Palatinate
At the 14 MeV stage of the 1508 MeV cascaded racetrack microtron accelerator Mainz Microtron (MAMI) fiber beam loss monitors with multi-anode photomultipliers (ma-PMTs) have been successfully tested. The combination of individual fibers for each recirculation beam pipe with ma-PMTs allows to detect beam losses turn by turn in the order of 10^-4 or even lower which cannot be accomplished with the already existing beam diagnostics. This kind of beam loss monitor might be an alternative to ionisation chambers for the new Mainz Energy Recovering Superconducting Accelerator (MESA).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW008

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

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WEPGW009

DEVELOPMENT OF THE ELECTRON BEAM PROBE FOR HADRON SYNCHROTRONS.

electron, simulation, hadron, proton

2480

M. Droba, C. Hübinger, O. Meusel, H. Podlech, K.I. Thoma
IAP, Frankfurt am Main, Germany
O.R. Jones, M. Wendt, F. Zimmermann
CERN, Meyrin, Switzerland

Funding: BMBF 05P18RFRB2
Non-invasive diagnostics is essential to get important information about intense hadron beams, e.g. the transverse beam profile, which is indispensable in order to attain high brilliance and luminosity for upgrades on present machines and for future projects. Furthermore, it can be used to optimise parameter settings in environment of the running machine. An electron beam probe (EBP) is a beam diagnostics instrument which scans a low energy, low current electron beam through a hadron beam and obtains information from the detected response. The electrons are shot perpendicular through the hadron beam to be examined, which causes deflection in the beam potential of the intense hadron bunch, that needs to be detected and further analysed. We propose to build the EBP scanning apparatus for synchrotrons under ultra-high vacuum condition. The results of multi particle simulations evaluating limitations the expected measurement potential and limitations are presented. This work will be performed in collaboration with CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW009

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paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW010

Diagnostics and First Beam Measurements at FLUTE

electron, laser, cathode, diagnostics

2484

T. Schmelzer, A. Bernhard, E. Bründermann, A. Böhm, S. Funkner, B. Härer, I. Križnar, A. Malygin, S. Marsching, W. Mexner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, M. Schuh, N.J. Smale, P. Wesolowski, M. Yan
KIT, Karlsruhe, Germany

FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact versatile linear accelerator at the Karlsruhe Institute of Technology (KIT). It serves as a platform for a variety of accelerator studies as well as a source of strong ultra-short THz pulses for photon science. In the commissioning phase of the 7 MeV low energy section the electron bunches are used to test the different diagnostics systems installed in this section. An example is the split-ring-resonator-experiment. In this contribution we report on the commissioning status of the beam diagnostics and present first beam measurements at FLUTE.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW010

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

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WEPGW017

Continuous Bunch-by-Bunch Reconstruction of Short Detector Pulses

detector, bunching, storage-ring, simulation

2501

J.L. Steinmann, M. Brosi, M. Caselle, B. Kehrer, M. Martin, A.-S. Müller, M.M. Patil, P. Schreiber
KIT, Karlsruhe, Germany

Funding: This work is funded by the BMBF contract number: 05K16VKA
The KAPTURE system (KArlsruhe Pulse Taking and Ultrafast Readout Electronics), developed at the Karlsruhe Institute of Technology (KIT), was designed to digitize detector pulses during multi-bunch operation at the KIT storage ring KARA (Karlsruhe Research Accelerator). KAPTURE provides digitization for pulses at rates of 500 MHz using up to 4 sampling points per pulse to record each bunch and each turn for potentially unlimited time. The new KAPTURE-2 system now provides eight sampling points per pulse, including baseline sampling between pulses, which allows improved reconstruction of the pulse shape. The advanced reconstruction of the pulse shape is realized with a highly parallelised implementation on GPU. The system will be used for the investigation on longitudinal beam dynamics e.g. by measuring instability induced CSR fluctuations or arrival time oscillations. This contribution will report on first results of the KAPTURE-2 system at KARA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW017

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

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WEPGW018

An Ultra-Fast and Wide-Spectrum Linear Array Detector for High Repetition Rate and Pulsed Experiments

detector, radiation, electron, synchrotron

2504

M.M. Patil, E. Bründermann, M. Caselle, S. Funkner, B. Kehrer, A.-S. Müller, G. Niehues, W. Wang, M. Weber
KIT, Karlsruhe, Germany
C. Gerth
DESY, Hamburg, Germany
D.R. Makowski, A. Mielczarek
TUL-DMCS, Łódź, Poland

Funding: "BMBF: is funded by the BMBF contract number: 05K16VKA" (2016-2018) ("NeoDyn")
Photon science research at accelerators is influenced radically by the developments of sensor and readout technologies for imaging. These technologies enable a wide range of applications in beam diagnostics, tomography and spectroscopy. The repetition rate of commercially available linear array detectors is a limiting factor for the emerging synchrotron applications. To overcome these limitations, KALYPSO(Karlsruhe Linear arraY detector for MHz rePetition rateSpectrOscopy), an ultra-fast and wide-field of view linear array detector operating at several mega-frames per second(Mfps), has been developed. A silicon micro-strip sensor is connected to custom cutting-edge front end ASICs to achieve unprecedented frame rate in continuous readout mode. In this contribution, the third generation of KALYPSO will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW018

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

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WEPGW019

Performance of the CVD Diamond Based Beam Quality Monitoring System in the HADES Experiment at GSI*

monitoring, detector, extraction, target

2507

A. Rost, T. Galatyuk
TU Darmstadt, Darmstadt, Germany
J. Adamczewski-Musch, S. Linev, J. Pietraszko, M. Sapinski, M. Traxler
GSI, Darmstadt, Germany

Funding: Work supported by the DFG through GRK 2128 and VH-NG-823.
The beam quality monitoring of extracted beams from SIS18 at GSI, transported to the HADES experiment is of great importance to ensure a high efficient data recording. The main detector system used for this purpose is the Start-Veto system which consists of two diamond based sensors made of pcCVD and scCVD diamond materials. Both sensors are equipped with a double-sided strip segmented metallization (300 µm width) which allows a position determination of the beam. Those sensors are able to deliver a time precision <100 ps and can handle rate capabilities up to 10⁷ particles/s/channel. Beside the diamond sensors a plastic scintillation based beam halo detector is used. The read-out of the detectors is based on the TRB3 system*. A 264 channel TDC (Time to Digital Converter) is implemented in FPGA technology with 10 ps precision. The TRB3 system serves as a fast and flexible Data Acquisition System (DAQ) with integrated scaler capability. The analysis and online visualization is performed using the Data Acquisition Backbone Core (DABC)** framework. In this contribution the performance of the system, which was used in order to evaluate an Ar and Ag ion beam delivered by the SIS 18 accelerator, will be discussed.
* A. Neiser et al., JINST 8 (2013) C12043
** J. Adamczewski-Musch et al., J.Phys. Conf. Ser. 664 (2015) no.8, 082027

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW019

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

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WEPGW031

Measurement of Cherenkov Diffraction Radiation from a Short Electron Bunches at t-ACTS

electron, radiation, photon, detector

2536

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

Cherenkov Diffraction Radiation (ChDR) can be considered as a tool of non-destructive beam diagnostics. It also has the feature that the photon flux of ChDR is proportional to the thickness of the dielectric used as the radiator and can be much larger than ordinary diffraction radiation. An experimental set-up for the measurement of coherent ChDR from short electron bunches of about 100 fs is being prepared at t-ACTS, Tohoku University. Results of a basic experimental study about coherent ChDR will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW031

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

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WEPGW032

Evaluation of 2-D Transverse Beam Profile Monitor Using Gas Sheet at J-PARC LINAC

injection, linac, simulation, factory

2539

J. Kamiya, Y. Hikichi, M. Kinsho, K. Moriya, N. Ogiwara, K. Okabe
JAEA/J-PARC, Tokai-mura, Japan
K. Wada
Tokyo Electronics Co. Ltd., Kokubunji, Tokyo, Japan
I. Yamada
Doshisha University, Graduate School of Engineering, Kyoto, Japan

A transverse beam profile monitor, which detects ions or luminescence generated by the interaction between the beam and the gas molecules distributed in a sheet shape, has been developed in the J-PARC LINAC. To know about the gas density distribution of the sheet-shaped gas, which affects the intensity distribution of the detected signal, the calculation by the Monte Carlo simulation code was performed. The calculation results showed that the gas with a narrow width along beam direction distributes enough uniformly within a realistic beam cross-sectional size. In addition, the unsaturated region against the MCP voltage and the injected gas pressure are evaluated based on the measurement with a beam. The results showed that the measurement in the low injected gas pressure with the appropriate applied voltage range is important to measure the beam profile in the unsaturated region.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW032

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paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW037

Development of a Dense Gas Sheet Target for a 2D Beam Profile Monitor

electron, simulation, vacuum, target

2554

N. Ogiwara, Y. Hori
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Hikichi, J. Kamiya, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
I. Yamada
Doshisha University, Graduate School of Engineering, Kyoto, Japan

We have been developing a dense gas sheet target to realize a non-destructive and fast-response beam profile monitor for the accelerators in J-PARC. The beaming effect in vacuum science and technology has been employed for making a gas sheet. The gas sheet with a thickness of ~ 1 mm and the density of 2 x 10^-4 Pa was successfully obtained. Then, we have successfully measured the profiles of the 400 MeV H⁻ ion beam in J-PARC linac by detecting the ions generated through the collision of this gas sheet to the H⁻ beam. This time, we have developed the gas sheet with the density of more than 10-3 Pa using a circular slit. The details of the new gas sheet generator will be shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW037

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

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WEPGW038

Beam Control and Monitors for the Spiral Injection Test Experiment

injection, electron, solenoid, site

2557

M.A. Rehman
Sokendai, Ibaraki, Japan
K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa
KEK, Ibaraki, Japan
H. Iinuma
Ibaraki University, Hitachi, Ibaraki, Japan

A new experiment at J-PARC (E34) is under construction in order to measure the muon’s g-2 to unprecedented precision of 0.1 ppm and electric dipole moment up to the sensitivity of 10-21 e.cm in order to explore new physics beyond the standard model. A novel three-dimensional 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 storage magnet. However, spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) is underway to establish this injection scheme. The SITE is consist of 80 keV thermionic electron gun, two-meter-long beamline, and a solenoidal storage magnet. In order to match the beam with the solenoidal field, several optical elements have been placed on the beamline to control the beam phase space. The DC electron beam spiral track has been confirmed by the de-excitation of the nitrogen gas in the vacuum chamber of the storage magnet. A current monitor system has been developed in order to extract the beam current and geometrical information of three-dimensional trajectory. An electric chopper system to produce the pulsed beam and beam monitors to detect the pulsed beam will also be discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW038

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

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WEPGW041

Development of a Gas Distribution Measuring System for Gas Sheet Beam Profile Monitor

electron, injection, detector, simulation

2567

I. Yamada
Doshisha University, Graduate School of Engineering, Kyoto, Japan
Y. Hikichi, J. Kamiya, M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan
N. Ogiwara
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The beam profile monitor is needed for measuring one of the beam parameters of high intensity accelerator to avoid radioactivating the systems. A monitor with sheet-shaped gas that can measure the beam profile nondestructively in two dimensions is developing. One of issues to introduce the monitor in accelerator is that the gas distribution is not uniform. Obtaining correct beam profile data needs to measure the gas distribution data because signal from the monitor is in proportion to beam intensity and gas distribution. A system analyzing distribution of ions produced from the gas using electron beam to measuring gas distribution in three dimensions is developing. An electron gun that produces ideal narrow beam, electrodes that forms parallel electric field toward micro-channel plate(MCP), and phosphor constitute the system. The electron beam that ionizes the gas which needs to be measured, produced ions are induced to MCP, and image on phosphor gives gas distribution data. In preliminary experiment for inspecting the measuring principle, experimental results agreed with simulation. The details of this system and the results of gas measuring experiment are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW041

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paper received ※ 28 April 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPGW042

Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment

laser, linac, acceleration, DTL

2571

M. Yotsuzuka, K. Inami
Nagoya University, Nagoya, Japan
K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, R. Kitamura, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226.
The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW042

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

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WEPGW053

Study with Wire Scanner and Beam Loss Monitor at CSNS-LINAC

MEBT, electron, linac, neutron

2598

J.L. Sun, R.Y. Qiu, T. Yang
IHEP CSNS, Guangdong Province, People’s Republic of China
J.M. Tian, T.G. Xu, Zh.H. Xu, L. Zeng
IHEP, Beijing, People’s Republic of China

China Spallation Neutron Source (CSNS) consists of 80 MeV H⁻ LINAC, 1.6 GeV RCS, RTBT line and one target. Many wire scanners and beam loss monitors (BLM) distributed along the LINAC and the RTBT for the profile and beam loss measurement. For the wire scanner, signal on the wire induced by the secondary electron is used for the profile measurement. Signal lost may happen when the wire or the signal chain shorted, thus a backup readout chain is required for the accident condition. As for the BLM, it is difficult to do the online calibration to see how sensitive the monitor is. Based on the two requests above, a crosscheck study was carried out recently, one wire scanner and the BLM next to it were chose at LINAC and RTBT. Both wire signal and BLM signal were recorded while the wire scanner crossing the beam. We found these two type of signals have the same accuracy for the profile measurement, and ~ 1 μA beam loss induced by the wire disturbance can be detected. Also thermal electron emission suspected happening during the measurement. More detailed experiment will be carried out in December. Secondary electron emission efficiency of the tungsten wire and thermal electron emission rate will be verified then.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW053

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

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WEPGW055

Beam Longitudinal Distribution Reconstructed by GESPAR Method at CAEP THz FEL

radiation, electron, FEL, laser

2602

D. Wu, T.H. He, P. Li, J. Liu, X. Luo, Q. Pan, L.J. Shan, X. Shen, J. Wang, D.X. Xiao, L.G. Yan, P. Zhang, K. Zhou
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

Funding: Work supported by National Natural Science Foundation of China with grant (11505173, 11505174, 11575264, and 11605190)
Coherent radiation can be used to measure the longitudinal distribution of the electron beam bunch of any length, as long as the coherent radiation spectrum can be measured. In many cases, the Kramers-Krönig relationship is used to reconstruct the temporal distribution of the beam from the coherent radiation spectrum. However, the extrapolation of the low frequency will introduce the uncertainty of the reconstruction. In this paper, GrEedy Sparse PhAse Retrieval (GESPAR) method was used to reconstruct the beam longitudinal distribution measured by coherent transition radiation on the THz FEL facility of China Academy of Engineering Physics. The results indicate that the GESPAR method works well for the complex and ultrashort distribution. It will be an effective tool to accurately measure the femtosecond bunch temporal structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW055

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paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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WEPGW057

Design of Stripline BPM for the SHINE Project

FEL, simulation, diagnostics, beam-diagnostic

2605

T. Wu, B. Gao, L.W. Lai, Y.B. Leng
SSRF, Shanghai, People’s Republic of China
S.S. Cao, J. Chen, Y.M. Zhou
SINAP, Shanghai, People’s Republic of China

As a under-constrution forth-generation light source in China, SHINE(Shanghai HIgh repetition rate XFEL aNd Extreme light facility) is expected to play an important role in basic scientific research in the field of materials and medicine. However, the performance of FEL depends critically on the completeness and quality of their beam diagnostic systems. Since the SHINE project will operate with bunch charge at 100pC, which is only one-quarter of that in the SXFEL, the measurement accuracy requirements for SBPM will increase significantly. On the other hand, the bunch repetition frequency of SHINE reached 1MHz, which shortened the threshold for measuring dead time. Fitting the requirement, the passband and the sampling rate design of stripline BPM is upgraded for the SHINE project. The final design was simulated using the data on the SXFEL, and the some inspiring results have been made.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW057

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

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WEPGW061

Bunch Length Measurement Using Multi-Frequency Harmonic Analysis Method at SSRF

SRF, storage-ring, operation, framework

2616

Y.M. Zhou, B. Gao, Y.B. Leng, N. Zhang
SSRF, Shanghai, People’s Republic of China

Harmonics method in the frequency domain is an effective and inexpensive bunch length measurement method, which was implemented at the Shanghai Synchrotron Radiation Facility (SSRF). A multi-frequency bunch-bybunch length measurement system using an integrated RF conditioning module will be established to reduce the system noise and signal reflection, and to improve the bunch length measurement accuracy as well. The module consists of power splitters, band-pass filters, mixers and so on. The main function of the integrated RF conditioning module is to extract the beam signals at 500MHz, 1.5GHz, 2GHz, and 3GHz operating frequency. Raw data are acquired by a high-precision digitizer and analyzed by MATLAB code. The absolute bunch length can be obtained with a streak camera, which was used to calibrate the response coefficients of the system. Bunch-by-bunch length can be measured by the multi-frequency harmonic analysis method from the button BPM

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW061

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

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WEPGW077

Recent Results using Incoherent Cherenkov Diffraction Radiation for Non-Invasive Beam Diagnostics

radiation, photon, diagnostics, beam-diagnostic

2654

M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
A. Aryshev
KEK, Ibaraki, Japan
P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
P. Karataev, K. Lekomtsev
JAI, Egham, Surrey, United Kingdom
A. Potylitsyn
TPU, Tomsk, Russia
A. Schloegelhofer
TU Vienna, Wien, Austria

When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW077

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paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW078

Development and Test of a Beam Imaging System Based on Radiation Tolerant Optical Fiber Bundles

radiation, laser, target, site

2658

D. Celeste, E. Bravin, S. Burger, F. Roncarolo
CERN, Geneva, Switzerland

Many of the beam image systems at CERN are located in high radiation environments. In order to cope with this issue, VIDICON cameras are presently used but their production has been nowadays discontinued worldwide. The development of an alternative beam imaging system is described here, based on radiation tolerant optical fibre bundles. Such an optical line relays the image of a scintillating screen to a standard CMOS camera, located away from the high radiation zone. A prototype system based on a 10m long bundle with 10⁴ fibres has been tested in the TT2 transfer line at CERN. The light transmission is rather low, but is compensated by the sensitivity of the CMOS camera. The system had a field of view of 60 mm and a spatial resolution of ~1 mm. The radiation hardness of such a fiber bundle was tested at the IRMA-CEA facility in Saclay, France. The bundle was irradiated at a rate of 3.6 kGy/h for 8 consecutive day. The total integrated dose achieved was ~700 kGy, which corresponds to about ten years of operation at the beam imaging station with the highest radiation dose at CERN. While the light transmission was reduced by 50%, this is still adequate to provide acceptable images.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW078

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

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WEPGW089

Calibration of the AWAKE Electron Spectrometer with Electrons Derived from a Partially Stripped Ion Beam

electron, proton, quadrupole, plasma

2694

D.A. Cooke, M. Cascella, J. Chappell, S. Jolly, F. Keeble, M. Wing
UCL, London, United Kingdom
R. Alemany-Fernández, J. Bauche, I. Gorgisyan, E. Gschwendtner, V. Kain, M.W. Krasny, S. Mazzoni, A.V. Petrenko
CERN, Meyrin, Switzerland
P. La Penna, M. Quattri
ESO, Garching bei Muenchen, Germany

The energy distribution of electrons accelerated in the wake of a self-modulated proton beam is measured using a magnetic spectrometer at AWAKE. The spectrometer was commissioned in 2017 and ran successfully throughout 2018. Imaging properties of the spectrometer system are studied via a combination of simulations and linear optics models and validated using mono-energetic electrons stripped from the partially stripped ion beam in the AWAKE beamline at CERN. These and other details of the calibration and performance will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW089

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

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WEPGW093

Commissioning of the Prototype for a New Gas Curtain Beam Profile Monitor Using Beam Induced Fluorescence for HL-LHC

electron, photon, gun, background

2709

A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
M. Ady, N. Chritin, J. Glutting, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider, R. Veness
CERN, Geneva, Switzerland
P. Forck, S. Udrea
GSI, Darmstadt, Germany
C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is supported by the HLLHCUK project and the STFC Cockcroft Institute core grant No. ST/G008248/1.
A new supersonic gas-jet curtain based beam profile monitor is under development for minimally invasive simultaneous transverse profile diagnostics of proton and electron beams, at pressures compatible with LHC. The monitor makes use of a thin gas-jet curtain angled at 45 degrees with respect to the charged particle beams. The fluorescence caused by the interaction between the curtain and the beam can then be detected using a dedicated imaging system to determine its transverse profile. This contribution details design features of the monitor, discusses the gas-jet curtain formation and presents various experimental tests, including profile measurements of an electron beam using nitrogen and neon curtains. The gas-jet density was estimated by correlating it with the number of photons detected by the camera. These measurements are then compared with results obtained using a movable pressure gauge. This monitor has been commissioned in collaboration with CERN, GSI and the University of Liverpool. It serves as a first prototype of a final design that will be placed in the LHC beam line to measure the profile of the proton beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW093

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

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WEPGW103

Synchrotron Radiation Beam Diagnostics at IOTA - Commissioning Performance and Upgrade Efforts

electron, optics, radiation, detector

2732

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
J.D. Jarvis, A.L. Romanov, J.K. Santucci, G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. A key part of its beam diagnostics suite are synchrotron radiation monitors, used for measuring transverse beam profile, position, and intensity. In this paper, we report on the performance and uses of this system during the year 1 run. We demonstrate sub-100nm statistical beam position uncertainty and high dynamic range from 10⁹ electrons down to a single electron. Commissioning challenges and operational issues are discussed. We conclude by outlining current upgrade efforts, including improved modularity, small emittance measurements, and a multi-anode photomultiplier system for turn-by-turn acquisition.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW103

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

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WEPGW105

Measuring Beam Parameters with Solenoid

solenoid, focusing, cathode, emittance

2739

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

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

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

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

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WEPGW106

Statistical Measurement of Longitudinal Beam Halo in Fermilab Recycler

detector, data-acquisition, booster, scattering

2742

E. Prebys, T.M. Nguyen
UCD, Davis, California, USA
A.S. Dyshkant, D. Hedin
Northern Illinois University, DeKalb, Illinois, USA
A. Gaponenko
Fermilab, Batavia, Illinois, USA
R.J. Hooper
Lewis University, Romeoville, Illinois, USA
M. Jones
Purdue University, West Lafayette, Indiana, USA

Funding: This work supported by US Department of Energy Contract DE-AC02-07CH11359
The formation of non-Gaussian halo in both the transverse and longitudinal dimensions of beam bunches has been notoriously difficult both the model and to measure. We present a technique to measure the longitudinal halo of 2.5 MHz bunches in the Fermilab Recycler, which have been formed for the g-2 anomalous magnetic moment experiment. While out of time beam is not a particular concern to this experiment, it is a key issue for the subsequent Mu2e rare muon decay experiment, which will use the same bunch formation procedure. Our measurement relies on a statistical technique, in which a small fraction of the beam is scattered from the primary collimation foil in the recycler, and then is detected by a charge telescope consisting of quartz Cherenkov radiators and photomultiplier tubes. By integrating over many revolutions, the time profile of longitudinal halo (out-of-time beam) can be measured down to less than a 10^-5 fractional level, relative to in-time beam. These results can then be compared to simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW106

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

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WEPGW114

Interferometric Measurement of Bunch Length of a 3Mev Picocoulomb Electron Beam

laser, electron, cathode, space-charge

2766

X. Yang, M. Babzien, B. Bacha, G.L. Carr, W.X. Cheng, L. Doom, M.G. Fedurin, B.N. Kosciuk, J.J. Li, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, C. Swinson, L.-H. Yu, Y. Zhu
BNL, Upton, Long Island, New York, USA

Funding: BNL LDRD
We report the bunch length measurement of low-energy 3 MeV electron beams in picosecond regime with the charge from 1.0 to 14 pC. It is the first time that we demonstrate single-cycle nano-joule coherent terahertz (THz) radiation from 3MeV electron beam can be meas-ured via a far-infrared Michelson interferometer using a QOD. At this low energy range, when charge is about 1 pC, the signal from the conventional helium-cooled sili-con composite bolometer is too low. Compared to the bunch length measurement via the ultrafast-laser-pump and electron-beam-probe in the timescale 10^-14 to 10-12 s which is determined by the phase-transition dynamics in solids, the advantages are: there are no needs of pump laser and probe sample, greatly simplifying the experi-ment; the timing jitter between laser and electron beams contributes no error to the bunch length measurement; furthermore, the method can be extended to sub-picosecond regime enabling bunch length measurement in a much broader timescale 10-14 to 10-11 s for low-energy electron beams. In the current experiment the bunch length is limited to 1 ps only because the setup of driving laser to cathode with a large 70° incident angle, effective-ly lengthening the laser pulse to ≥1 ps.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW114

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

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WEPGW122

EXPERIMENTAL VERIFICATION OF TRANSPARENT SPIN MODE IN RHIC

polarization, collider, controls, resonance

2783

V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang
JLab, Newport News, Virginia, USA
P. Adams, H. Huang, F. Méot, V. Ptitsyn, W.B. Schmidke
BNL, Upton, Long Island, New York, USA
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
H. Huang
ODU, Norfolk, Virginia, USA
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Funding: Supported in part by the U.S. DoE under Contract No. DE-AC05-06OR23177 and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DoE.
High electron and ion polarizations are some of the key design requirements of a future Electron Ion Collider (EIC). The transparent spin mode, a concept inspired by the figure 8 ring design of JLEIC, is a novel technique for preservation and control of electron and ion spin polarizations in a collider or storage ring. It makes the ring lattice "invisible" to the spin and allows for polarization control by small quasi-static magnetic fields with practically no effect on the beam’s orbital characteristics. It offers unique opportunities for polarization maintenance and control in Jefferson Lab’s JLEIC and in BNL’s eRHIC. The transparent spin mode has been demonstrated in simulations and we now plan to test it experimentally. We present a design of an experiment using a polarized proton beam stored in one of the RHIC rings. In the experiment, one of the RHIC rings is configured in the transparent spin mode by aligning the axes of its two Siberian snakes. The experiment goals, procedures, hardware requirements and expected results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW122

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

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WEPRB051

MA RF Cavity Design and Simulation for CSNS/RCS Upgrade Project

cavity, simulation, synchrotron, detector

2925

B. Wu
IHEP CSNS, Guangdong Province, People’s Republic of China
X. Li, H. Sun
IHEP, Beijing, People’s Republic of China

The dual harmonic RF system will be adapted for Chi-na Spallation Neutron Source (CSNS) upgrade project. Limited locations in CSNS/RCS are reserved to install additional three 2nd harmonic cavities. The cavity loaded by magnetic alloy (MA) material would be used. Because of the low Q factor of the MA core, the cavity cooling be-comes a very important issue in cavity design. Air-forced, indirect and direct cooling scheme were studied. The fluid thermodynamic of different cooling structure were simu-lated by ANSYS CFX which considered the anisotropy of thermal conductivity of MA core. The limitation of these cooling schemes were discussed in detail based on the simulation results. Indirect cooling experiment was done to assess the cooling efficiency and verify the simulation result. A high power test cavity cooled by water has been designed to estimate the property of the MA core and cooling effectiveness for CSNS/RCS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB051

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paper received ※ 08 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB065

Multi-physics Computation and Deformation Testing of a Shell-type 1.5-GHz Cavity

cavity, SRF, resonance, synchrotron

2968

M.-C. Lin, C.H. Lo
NSRRC, Hsinchu, Taiwan
M.-R. Lu, M.-K. Yeh
NTHU, Hsinchu, Taiwan

Funding: Work supported by the Ministry of Science and Technology, R. O. C. (Taiwan) under grant NSC-100-2628-E-213-001-MY3.
A copper prototype of a 1.5-GHz cavity was manufac-tured to simulate a superconducting radio-frequency cavity for technique development. Frequency tuning with longitudinal compression of this prototype and cryogenic cooling with liquid nitrogen were performed to examine the numerical results from finite-element models, mainly the corresponding shifts of the fundamental resonant frequency. An appropriate element option improved the accuracy of the resonant frequency and the distribution of the magnetic field. Effects of geometry distortion of an uneven length on the frequency shift of this shell-type cavity as loaded on longitudinal compression are also examined and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB065

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paper received ※ 25 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPRB089

Theoretical Analysis of Quasiparticle Overheating, Positive Q-Slope, and Vortex Losses in SRF Cavities

cavity, SRF, niobium, electron

3020

J.T. Maniscalco, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
T. Arias, D. Liarte, J.P. Sethna, N. Sitaraman
Cornell University, Ithaca, New York, USA

The surface resistance of an SRF cavity is an important measure of its performance and utility: lower resistance leads directly to lower cryogenic losses and power consumption. This surface resistance comprises two components, namely the ‘‘BCS resistance’’, which depends strongly on the quasiparticle temperature, and a temperature-independent ‘‘residual resistance’’, which is often dominated by losses due to trapped magnetic vortices. Both components are generally dependent on the RF field strength. Here we present a summary of recent theoretical advances in understanding the microscopic mechanisms of the surface resistance, in particular addressing niobium hydride formation and quasiparticle overheating (using the tools of density functional theory) and discussing issues with existing models of the positive Q-slope, a field-dependent decrease in the BCS resistance, and possible paths for improvement of these models. We also discuss trapped flux losses using ideas from collective weak pinning theory.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB089

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

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WEPRB110

Recent Results from Nb₃Sn-Coated Single-cell Cavities Combined with Sample Studies at Jefferson Lab

cavity, SRF, superconductivity, niobium

3066

U. Pudasaini, M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
G. Ciovati, G.V. Eremeev, M.J. Kelley, C.E. Reece
JLab, Newport News, Virginia, USA
I.P. Parajuli
ODU, Norfolk, Virginia, USA

Funding: Partially authored by Jefferson Science Associates under contract no. DEAC0506OR23177. Supported by Office of High Energy Physics under grants DE-SC-0014475 and DE-SC-0018918.
The critical temperature (~ 18 K) and superheating field (~ 425 mT) of Nb₃Sn are almost twice that of niobium, thereby promising the higher quality factor and accelerating gradient at any given temperature compared to traditional SRF cavities made of niobium. It can enable higher temperature for cavity operation (4 K Vs. 2 K), resulting in significant reduction in both capital and operating cost for the cryoplant. Several single-cell cavities along with witness samples were coated with Nb₃Sn to explore, understand and improve the coating process for betterment of cavity performance. RF measurements of coated cavities combined with material characterization of witness samples were employed to update the coating process. Following some modifications to the existing coating process, we were able to produce Nb₃Sn cavity with quality factor ≥ 2.10¹⁰ for accelerating gradient up to 15 MV/m at 4 K, without any significant Q-slope. In this article, we will discuss recent results from several Nb₃Sn coated single-cell cavities combined with material studies of witness samples.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB110

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

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WEPRB114

Understanding and Pushing the Limits of Nitrogen Doping

cavity, SRF, niobium, ECR

3078

D. Bafia, M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
D. Bafia, J. Zasadzinski
IIT, Chicago, Illinois, USA
D. Gonnella
SLAC, Menlo Park, California, USA
A.D. Palczewski
JLab, Newport News, Virginia, USA

This work will describe Fermilab experiments that focus on the optimization of doping parameters to achieve low sensitivity to trapped magnetic flux while maintaining very high Q characteristic of nitrogen doped cavities and same or higher quench fields. Working partially in the context of LCLS-2 higher energy upgrade, new doping recipes are pursued and have been found to vary the mean free path of the resonator which is related to the sensitivity to trapped magnetic flux. Moreover, a correlation has been found between lighter doping and higher quench fields while maintaining sufficiently low surface resistance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB114

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

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WEPTS007

Short Bunch Experiment at EXALT Facility

laser, cathode, electron, gun

3100

C. Bruni, J-N. Cayla, S. Chancé, V. Chaumat, N. Delerue, N. ElKamchi, P. Lepercq, H. Purwar
LAL, Orsay, France
E. Baynard, M. Pittman
CLUPS, Orsay, France
B. Lucas, O. Neveu
CNRS LPGP Univ Paris Sud, Orsay, France
T. Vinatier
DESY, Hamburg, Germany

Nowdays, different applications required short bunches, with low energy spread and low emittances. On EXALT facility, we perform an experiment with a short (few100 femtosecond) laser pulse on a photocathode in a 3 GHz RF gun. We perform the measurement of the single photon emission process with a copper cathode. We show that the longitudinal photoinjector model via transfer matrix is suitable for the reconstruction of the bunch duration even in short pulse mode with an increased accurracy charge below 20 pC. We clearly measure the parabolic profile in the energy spectrum resulting from blow out phenomena at the cathode due to strong space charge forces. Measurements are also compared with the Astra simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS007

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

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WEPTS016

Longitudinal Beam Manipulation by RF Phase Modulation at the Karlsruhe Research Accelerator

simulation, synchrotron, cavity, beam-loading

3123

A. Mochihashi, E. Blomley, T. Boltz, E. Huttel, B. Kehrer, A.-S. Müller, M. Schuh
KIT, Karlsruhe, Germany
D. Teytelman
Dimtel, San Jose, USA

At the storage ring KARA (Karlsruhe Research Accelerator) of the Karlsruhe Institute of Technology (KIT) we have installed a function for the RF phase modulation to the low-level RF system. By choosing proper conditions of the modulation, the electron distribution on the longitudinal phase space can be changed in a large range. There are several applications of this longitudinal manipulation to the accelerator operation: an improvement of the beam lifetime and suppression of collective instabilities. We have performed tracking simulations for the longitudinal beam manipulation by the RF phase modulation. The results have implied that the longitudinal phase space distribution strongly depends on the modulation frequency. We have also performed experiments, which aimed at improving the beam lifetime in 2.5 GeV KARA multi-bunch operations. In this contribution, the low-level RF system at KARA, the simulation and experimental results under the RF phase modulation will be presented. As one of the options of the modulation, we consider manipulation of the internal fine structure in the longitudinal phase space by the modulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS016

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

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WEPTS018

Experimental Observation of Low-Order Collective Oscillation Modes in a Strong-Focusing Lattice

quadrupole, plasma, resonance, dipole

3130

K. Ito, H. Higaki, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan
T. Kurauchi
Hiroshima University, Faculty of Science, Higashi-Hirosima, Japan

In a conventional linear Paul trap (LPT), four electrode rods are placed symmetrically around the trap axis to generate a radio-frequency quadrupole field for transverse ion confinement. The periodic nature of the external focusing potential can give rise to serious ion losses under a specific condition. The loss mechanism is essentially the same as the coherent betatron resonance well-known in intense beam dynamics[*,**]. In fact, the collective motion of an ion plasma in the LPT is shown equivalent to that of a charged-particle beam traveling through an alternating-gradient focusing lattice. In the present study, we perform the direct measurement of low-order coherent oscillation modes in the LPT by detecting image currents induced on the electrodes’ surfaces. The four-rod structure of the LPT allows us to pick up feeble signals of the dipole and quadrupole oscillations of a plasma bunch. These signals are Fourier analyzed to evaluate the coherent oscillation tune at different initial ion densities. The time evolution of the coherent motion is also discussed in this paper.
* K. Moriya et al., Phys. Rev. Accel. Beams Vol.19, 114201 (2016).
** K. Ito et al., Phys. Rev. Accel. Beams Vol. 20, 064201 (2017).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS018

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

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WEPTS019

Accumulating Laser-Coolable Ions in a Linear Paul Trap for Ultrahigh-Density Beam Dynamics Experiment

plasma, laser, accumulation, quadrupole

3134

K. Ito, H. Higaki, T. Masuda, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan

An ion plasma confined in a linear Paul trap (LPT) exhibits the dynamic behavior physically equivalent to that of a charged-particle beam in an alternating-gradient transport channel. The Simulator of Particle Orbit Dynamics (S-POD) is a compact apparatus designed on the basis of this fact for diverse beam-physics experiments. We have so far employed Ar+ ions that can readily be produced from neutral Ar gas atoms through the electron bombardment process. A space-charge-induced tune shift of up to about 20% of the bare tune can be achieved in Ar+ plasmas [*]. We are now preparing for future S-POD experiment to explore even higher beam-density regions. For this purpose, a large number of Ca+ ions need to be stored in the LPT. Since S-POD is equipped with a powerful laser cooler for Ca+, the use of this ion species vastly expands the density range we can survey. The production of an intense bunch of Ca+ ions is, however, not so easy because of some technical reasons. By optimizing the operating condition of a multi-sectioned LPT, we succeeded in increasing the number of accumulated Ca+ ions to the level comparable to Ar+ ion plasmas. This paper reports on updated results of the experiment.
* K. Ito et al., Phys. Rev. Accel. Beams Vol. 20, 064201 (2017).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS019

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS026

Generalised Scattering Module in SixTrack 5

scattering, target, lattice, proton

3156

K.N. Sjobak
University of Oslo, Oslo, Norway
H. Burkhardt, R. De Maria, V.K.B. Olsen
CERN, Geneva, Switzerland

Funding: Research Council of Norway, project 255196, and HL-LHC WP8
A generalised scattering module has recently been added to SixTrack. This module enables the use of arbitrary generators and target profiles. Presently, a simple model of elastic scattering and a coupling to Pythia8 have been implemented. This makes it possible to use SixTrack for studies of aperture losses and beam lifetime as a result of beam–beam scattering.

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

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WEPTS044

Instability Latency in the LHC

octupole, feedback, damping, simulation

3204

S.V. Furuseth, D. Amorim, S.A. Antipov, X. Buffat, N. Mounet, E. Métral, B. Salvant
CERN, Geneva, Switzerland
S.V. Furuseth, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland

The Large Hadron Collider (LHC) has experienced multiple instabilities that occur between minutes and hours after the last modification of the machine settings. The existence of instabilities with high latency has been reproduced also in simulations. Dedicated experiments, injecting a controlled noise into the beam, have now been performed to discover the dependence of this latency on key parameters. The results seem compatible with a mechanism linked to a steady and slow modification of the transverse beam distribution leading to a loss of Landau damping.

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

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WEPTS046

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

emittance, luminosity, operation, proton

3212

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

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

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

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

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WEPTS048

Electron Beam Dynamics Simulation for Electron Lenses

electron, gun, simulation, cathode

3220

S. Sadovich, A. Rossi
CERN, Meyrin, Switzerland
G. Stancari
Fermilab, Batavia, Illinois, USA

A test stand is under construction at CERN to study high perveance electron guns, electron beam dynamics, and electron beam diagnostics for electron lenses. It will be used to test electron guns for the Hollow Electron Lenses under consideration for beam halo control for High Luminosity LHC (CERN), and for the Space Charge Compensation at SIS18 (GSI) in the frame of the EU funded ARIES project. In order to prepare for this test stand, simulations will be presented and compared with experiments undertaken at the Fermilab (FNAL) electron lens test stand. These were conducted using a hollow electron gun, with the magnetic field configuration and beam current varied to study their effect. The impact of imperfections on the beam dynamics and overall quality of the electron beam will be discussed. A method for comparing experimental data with simulation is also presented to allow bench-marking of the computer models and simulation tools that will later be applied to the analysis of measurements performed at CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS048

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

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WEPTS055

Energy Modulation of Electron Beam in Corrugated Dielectric Waveguide

simulation, wakefield, acceleration, electron

3248

A. Lyapin, S.T. Boogert, S.M. Gibson, K. Lekomtsev
JAI, Egham, Surrey, United Kingdom
A. Aryshev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A.A. Tishchenko
MEPhI, Moscow, Russia
A.A. Tishchenko
NRC, Moscow, Russia

Energy modulated electron beams have a wide range of applications in accelerator physics, for example they can serve as drivers in resonant wakefield acceleration schemes. A strong wakefield induced energy modulation can be produced using a dielectric lined waveguide, the resultant micro-bunched beam is capable of producing coherent terahertz radiation *. We report on observation of energy modulation due to self-wakefields in a few picosecond duration and ~1 nC charge electron bunches of LUCX facility at KEK. To produce the modulation, we used a corrugated dielectric waveguide with an inner radius of 2 mm and a period of corrugation of 10 mm. In this case, the period of corrugation is longer than the wavelength of the main accelerating mode. We show electromagnetic simulations of on-axis electric fields leading to an optimisation of the corrugation period allowing to enhance the accelerating/decelerating fields compared to dielectric lined waveguides with a constant inner radius.
* S. Antipov et al., Experimental observation of energy modulation in electron beams passing though terahertz dielectric wakefield structures, PRL 108, 144801 (2012).

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

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WEPTS056

Can a Paul Ion Trap Be Used to Investigate Nonlinear Quasi-Integrable Optics?

octupole, lattice, optics, quadrupole

3251

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

Here we describe the design of an experimental setup using the IBEX Paul trap to test nonlinear quasi-integrable optics, an accelerator lattice design to create stable high intensity beams. In 2010 Danilov and Nagaitsev found a realisable nonlinear potential which can create integrable optics in an accelerator when embedded in a linear lattice that provides round beams. This concept will be tested in the IOTA ring at Fermilab. It is important to further test this concept over a wide parameter range, preferably in a simplified experimental setup such as IBEX. The IBEX Paul trap is capable of replicating the transverse dynamics of a high intensity accelerator without dispersion or chromaticity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS056

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

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WEPTS057

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

resonance, emittance, simulation, space-charge

3255

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

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

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

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

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WEPTS058

BDSIM: Recent Developments and New Features Beyond V1.0

simulation, detector, radiation, site

3259

L.J. Nevay, A. Abramov, J. Albrecht, S.E. Alden, S.T. Boogert, H. Garcia Morales, S.M. Gibson, W. Shields, S.D. Walker
JAI, Egham, Surrey, United Kingdom
J. Snuverink
PSI, Villigen PSI, Switzerland

BDSIM is a program that creates a 3D model of an accelerator from an optical beam line description using a suite of high energy physics software including Geant4, CLHEP and ROOT. In one single simulation the passage of particles can be tracked accurately through an accelerator including the interaction with the accelerator material and subsequent secondary radiation production and transport. BDSIM is regularly used to simulate beam loss and energy deposition as well as machine detector interface studies. In this paper we present the latest developments beyond BDSIM V1.0 added for ongoing studies. For simulation of collimation systems several new additions are described including new element geometry, enhanced sensitivity and output information. The output has been further enhanced with aperture impact information and dose information from scoring meshes. As well as supporting the full suite of Geant4 physics lists, a new user interface is described allowing custom physics lists and user components to be easily included in BDSIM. New undulator, crystal collimator and wire-scanner elements are also described.

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

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WEPTS060

Multi-objective Optimization of 3D Beam Tracking in Electrostatic Beamlines

simulation, quadrupole, lattice, storage-ring

3263

V. Rodin, J.R. Hunt, J. Resta-López, B. Veglia, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.R. Hunt, J. Resta-López, V. Rodin, B. Veglia, 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 programme under the Marie Skłodowska-Curie grant agreement No 721559.
After CERN’s Long Shutdown 2 (LS2) the Extra Low Energy Antiproton (ELENA) ring will begin providing extremely low energy (100 keV) antiproton beams to the antimatter experiments in the AD hall. To allow for simultaneous operation and guarantee maximum efficiency, all transfer lines will be based on electrostatic optics and short pulse (∼100 ns) deflectors. Currently, only a limited number of simulation codes allow a realistic representation of these elements, limiting the capabilities for beam quality optimization. In this contribution methods for modelling realistic electrostatic optical elements and perform 3D tracking studies through these are presented. A combination of finite element methods and experimental measurements are used along with a modified version of the G4Beamline and BMAD codes. Multi-objective optimization techniques are then applied to optimize beam transfer and beam quality at various points along the transfer lines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS060

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

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WEPTS061

Experimental Test of Longitudinal Space-Charge Amplifier in Optical Range

electron, undulator, laser, FEL

3267

C. Lechner, M. Dohlus, B. Faatz, V. Grattoni, G. Paraskaki, J. Rönsch-Schulenburg, E. Schneidmiller, M.V. Yurkov, J. Zemella
DESY, Hamburg, Germany
V. Miltchev
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Longitudinal space-charge effects can act as a driver for short wavelength radiation production in a longitudinal space-charge amplifier (LSCA) *. A single cascade of an LSCA was tested using the hardware of the sFLASH experiment installed at the FEL user facility FLASH (at DESY, Hamburg). Scans of the longitudinal dispersion of the chicane were performed with the tightly focused electron beam for different compression settings, while recording the intensity of the emission from a few-period undulator. We present experimental results and estimates on electron beam properties.
* E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST Accel Beam 13, 110701 (2010)

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

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WEPTS070

First Measurements of Nonlinear Decoherence in the IOTA Ring

lattice, kicker, damping, optics

3286

C.C. Hall, D.L. Bruhwiler, J.P. Edelen
RadiaSoft LLC, Boulder, Colorado, USA
N. Kuklev
University of Chicago, Chicago, Illinois, USA
A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This work has been supported by the U.S. Department of Energy Office of Science, Office of High Energy Physics under Award No. DE-SC00111340
The Integrable Optics Test Accelerator (IOTA), at Fermi National Laboratory is aimed at testing nonlinear optics for the next generation of high intensity rings. Through use of a special magnetic element the ring is designed to induce a large tune spread with amplitude while maintaining integrable motion. This will allow for the suppression of instabilities in high-intensity beams without significant reduction in dynamic aperture. One important aspect of this is the nonlinear decoherence that occurs when a beam is injected off axis or receives a transverse kick while circulating in the ring. This decoherence has been studied in detail, with simulations, for protons in IOTA both with and without space-charge. However, it has yet to be demonstrated experimentally. During the first phase of the IOTA experimental program, the ring is operated with 100 MeV electrons, allowing for the study of nonlinear optics without the complications introduced by space charge. Here we present measurements taken during the IOTA commissioning, and an analysis of the results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS070

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

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WEPTS072

Application of Bayesian Inference in Accelerator Commissioning of FRIB

diagnostics, MMI, emittance, coupling

3289

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

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

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

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WEPTS094

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

emittance, solenoid, electron, quadrupole

3337

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

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

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

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WEPTS099

Passive Absorbers for Maximizing the Performance of the Mu2e-II Experiment

target, solenoid, proton, collimation

3345

J. Manczak
IFIC, Valencia, Spain
J. Manczak
Warsaw University, Warsaw, Poland
D.V. Neuffer, D. Stratakis
Fermilab, Batavia, Illinois, USA

The Fermilab’s Mu2e experiment is designed to search for Charged Lepton Flavour Violation in direct, neutrinoless conversion of muon into electron in the presence of a nucleus’ electromagnetic field. Quantity, which is going to be observed is the ratio between the rate of the above BSM (Beyond Standard Model) reaction and the rate of the standard muon capture on the nucleus. The measurement precision is expected to reach up to 10^-17. Mu2e-II is the codename for the second phase of the experiment planned to run with the lower energy, higher intensity primary proton beam provided by PIP-II accelerator, currently under construction. The ionization cooling with a wedge absorber is introduced to Mu2e-II setup for potential increase in the number of low momentum muons reaching the target. The study is made into the position and size of the wedge inside the beamline using G4Beamline simulation framework. Results show an increase up to 12% for muons with momentum P below 30 MeV/c and 7% for muons with P<40 MeV/c when the beam is measured right after the wedge. Further studies are necessary to investigate how this gain can be delivered to the stopping target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS099

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

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WEPTS100

The ESR Closed Orbit Calculation and Simulation

controls, simulation, electron, MMI

3349

S. Dastan, S. Dastan, R. Saffari
University of Guilan, Rasht, Iran
S. Dastan, J. Rahighi
ILSF, Tehran, Iran
S. Livinov, M. Steck
GSI, Darmstadt, Germany

The commissioning of the ESR with a new control system based on the LSA (LHC System Architecture) has started recently. This new control system is under development and considers all aspects of the expected functionality to operate the GSI/FAIR accelerators and incorporates the present GSI controls infrastructure*. Two years ago, the old control system which was based on outdated computers and operating system, was discontinued. So, both the heavy ion synchrotron SIS-18 and the Experimental Storage Ring (ESR) operation from now on have to be performed with the new FAIR control system. In order to introduce an improved model to the control system change, new calculations and simulations for SIS and ESR are necessary. In this paper we summarize the results of closed orbit calculations for the ESR which are done with three different codes, namely: ELEGANT*, MAD-X and MIRKO. Also, because the results of ELEGANT and MAD-X in this issue are similar to each other, we present ELEGANT results in the report.
* R. Bär, DEVELOPMENT OF A NEW CONTROL SYSTEM FOR THE FAIR ACCELERATOR COMPLEX AT GSI. Kobe.
** Borland, M., elegant: A Flexible SDDS-Compliant Code for Accelerator Simulation.

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paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS106

Accelerator Optimization using Big Data Science Techniques

plasma, radiation, electron, proton

3370

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 STFC under grant reference ST/P006752/1.
Managing, analyzing and interpreting large, complex datasets and high rates of data flow is a growing challenge for many areas of science and industry. At particle accelerators and light sources, this data flow occurs both, in the experiments as well as the machine itself. The Liverpool Big Data Science Center for Doctoral Training (LIV. DAT) was established in 2017 to tackle the challenges in Monte Carlo modelling, high performance computing, machine learning and data analysis across particle, nuclear and astrophysics, as well as accelerator science. LIV. DAT is currently training 24 PHD students, making it one of the largest initiatives of this type in the world. This contribution presents research results obtained to date in projects that focus on the application of big data techniques within accelerator R&D.

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

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WEPTS108

Emittance Exchange in MICE

emittance, collider, simulation, factory

3378

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

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

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

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THXXPLM2

Demonstration of Loss Reduction Using a Thin Bent Crystal to Shadow an Electrostatic Septum During Resonant Slow Extraction

extraction, operation, septum, optics

3399

F.M. Velotti, P. Bestmann, M.E.J. Butcher, M. Calviani, M. Di Castro, M. Donzé, L.S. Esposito, M.A. Fraser, M. Garattini, S.S. Gilardoni, B. Goddard, V. Kain, J. Lendaro, A. Masi, D. Mirarchi, M. Pari, J. Prieto, S. Redaelli, R. Rossi, W. Scandale, R. Seidenbinder, P. Serrano Galvez, L.S. Stoel, C. Zamantzas, V. Zhovkovska
CERN, Meyrin, Switzerland
F.M. Addesa, F. Iacoangeli
INFN-Roma, Roma, Italy
A.G. Afonin, Y.A. Chesnokov, A.A. Durum, V.A. Maisheev, Yu.E. Sandomirskiy, A.A. Yanovich
IHEP, Moscow Region, Russia
J.E. Borg, M. Garattini, G. Hall, T. James, M. Pesaresi
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
A.S. Denisov, Y. Gavrikov, Yu.M. Ivanov, M.A. Koznov, L.G. Malyarenko, V. Skorobogatov
PNPI, Gatchina, Leningrad District, Russia
F. Galluccio
INFN-Napoli, Napoli, Italy
F. Murtas
INFN/LNF, Frascati, Italy

A proof-of-principle experiment demonstrating the feasibility of using a thin, bent crystal aligned upstream of an extraction septum (ES) to increase the efficiency of the third-integer resonant slow extraction process has been carried out at the CERN Super Proton Synchrotron (SPS). With the primary aim of reducing the beam loss and induced radio-activation of the SPS, the crystal was aligned to both the beam and the septum to reduce by up to 40% the beam intensity impinging the ES and increase the intensity entering the external transfer line. In this contribution, we introduce the concept and the prototype system that was installed in 2018 before reporting in detail on the dedicated program of machine development studies carried out to characterise its performance and demonstrate operational feasibility. The performance reach and compatibility with other loss reduction techniques proposed to further increase the extraction efficiency, such as phase space folding with octupoles, is discussed in view of future high intensity operation.

Slides THXXPLM2 [1.397 MB]

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paper received ※ 15 May 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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THYYPLM2

Two Orbit Operation at Bessy II - During a User Test Week

injection, resonance, electron, operation

3419

P. Goslawski, F. Andreas, F. Armborst, T. Atkinson, J. Feikes, A. Jankowiak, J. Li, T. Mertens, M. Ries, A. Schälicke, G. Schiwietz, G. Wüstefeld
HZB, Berlin, Germany

Operating a storage ring close to a horizontal resonance and manipulating the transverse non-linear beam dynamics can generate stable Transverse Resonance Island Buckets (TRIBs), which give a 2nd stable orbit in the ring. Both orbits can be populated with different electron bunch filling patterns and provide two different radiation sources to the user community. Such a machine setting has been established at BESSY II and was tested under realistic user conditions in a first ’TRIBs/Two Orbit User Test Week’ in February 2018. Results and user feedback will be discussed in this contribution.

Slides THYYPLM2 [64.754 MB]

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paper received ※ 14 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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THAPLM3

2019 Nishikawa Tetsuji Prize Talk

electron, collider, proton, operation

3439

V.D. Shiltsev
Fermilab, Batavia, Illinois, USA

For his original work on electron lenses in synchrotron colliders, his outstanding contribution to the construction and operation of high-energy, high-luminosity hadron colliders and for his tireless leadership in the accelerator community.

Slides THAPLM3 [17.631 MB]

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

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THPMP006

Study on the Theta Pinch Plasmas for Applied as Ion Stripper

plasma, electron, target, heavy-ion

3456

K. Cistakov, Ph. Christ, M. Fröhlich, M. Iberler, J. Jacoby, L. Manganelli, G. Xu
IAP, Frankfurt am Main, Germany
R. Gavrilin, A. Khurchiev, S.M. Savin
ITEP, Moscow, Russia

Funding: Work supported by BMBF contr. No. 05P18RFRB1
With regard to the development of new accelerator technologies for high-intensity ion beams and more efficient acceleration, the transfer of radiation ions to higher charged states is a prerequisite for many experiments. However, the recent stripping technologies such as film and gas stripper for heavy ion beams with the desired intensities required great effort or are not suitable. The contribution presents the current state of plasma strippers with fully ionized hydrogen with simultaneously high particle densities in the range of some 10¹⁷ cm^-3 for FAIR. To achieve this high particle density, an inductive discharge plasma is ignited within a stripper cell parallel to the axis of the ion beam and compressed towards the beam axis. The advantage over conventional ion strippers is about 1000 times smaller recombination rate for electrons*. This significantly increases the equilibrium charge state of ions. At the same time, the relative fraction of ions on the maximum of charge state distribution increases up to 25%**. This should create good conditions for the use of plasma strippers at FAIR.
*Th.Peter, "Energy loss of heavy ions in dense plasma"
**O.Haas, "Simulation Studies of plasma-based charge strippers",Proceedings of IPAC 2015, Richmond, VA, USA

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

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THPMP011

Optics and Commissioning of the CNAO Experimental Beam Line

radiation, proton, MMI, optics

3472

S. Savazzi, E. Bressi, L. Falbo, V. Lante, C. Priano, M.G. Pullia
CNAO Foundation, Pavia, Italy
P. Meliga
University of Pavia, Pavia, Italy

CNAO (National Centre for Oncological Hadronthera-py) in Pavia is one of the six centres worldwide in which hadrontherapy is administered with both protons and carbon ions. The main accelerator is a 25 m diameter synchrotron designed to accelerate carbon ions up to an energy of 400 MeV/u and protons up to an energy of 250 MeV. It was designed with three treatment rooms and an ’experimental room’ where research can be carried out. The room itself was built since the beginning, but the beam line was planned to be installed in a second moment in order to give priority to treatments. The beam line of the experimental room (XPR) is designed to be "general purpose", for research activities in different fields. In October 2018 the installation phase of the line was started and it ended in January 2019. In this paper a short description of the optics layout and commissioning strategy is given.

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

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THPMP016

Design of the Condenser System and Imaging System for a UEM

electron, gun, cathode, cavity

3485

T. Chen, W. Li, Y.J. Pei
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The ultrafast electron microscope provides a useful tool for exploring fine structure and observing dynamic process at nanometer and picosecond scale, which has been extensively applied in chemistry and biological field. After emitting from the electron gun, electron beams are focused on the stage sample by the condenser system and then be projected by the imaging system on the screen. In the present study, a two-lens condenser system is simulated by Parmela and a three-lens imaging system is designed using thin-lens approximation. Besides, the shape factor of metallic spheres which have different radius for perturbation method is measured, which is conductive to measuring the Z/Q parameter and the electric field along the axis of the C-band 3MeV photocathode gun for the UEM.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP016

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

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THPMP020

Single-Shot Cascade High Energy Electron Radiography based on Strong Permanent Magnet Quadrupole Composed Imaging Lens

electron, simulation, quadrupole, optics

3491

Z. Zhou, Y.-C. Du, W.-H. Huang
TUB, Beijing, People’s Republic of China

High energy electron imaging, an extension of conventional transmission electron microscopy, is suitable for imaging of thicker objects and expected to be a promising tool for diagnostics of high energy density physics (HEDP). A cascade high energy electron imaging system using two-stage imaging lenses based on strong permanent magnet quadrupoles is designed, optimized and finally installed at Tsinghua university. Encouraging result of 1.6-μm space resolution is obtained in our primary experiments, along with the clear imaging of a spherical capsule as a substitute of the targets used in inertial confinement fusion. Successful implement of cascade high energy electron imaging system is necessary for reaching better resolving power of the imaging system, and well matching of design, simulation with experimental results paves the way to high energy electron microscopy to provide full capacities for diagnostics of HEDP with sub-um and picosecond spatiotemporal resolutions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP020

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

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THPMP027

Concept of Radiographic Complex Based on Ironless Pulsed Betatrons for Small-Angle Tomography

betatron, radiation, collimation, ion-source

3503

O.A. Shamro, A.A. Chinin, V.A. Fomichev, Yu.P. Kuropatkin, V.I. Nizhegorodtsev, K.V. Savchenko, V.D. Selemir
RFNC-VNIIEF, Sarov, Nizhniy Novgorod region, Russia

The active research complexes intended for the radiography of dynamic objects with a high optical density are reviewed. The concept of a multi-beam radiographic complex for a small-angle tomography based on ironless pulsed betatrons is proposed*. It is possible to use up to 18 compact facilities in a complex; they are located in three horizontal planes. The test object is placed in the explosion-proof chamber. Each facility consists of two typical units: an accelerator unit, and a unit of the electromagnet pulsed powering system. The output parameters of the facility are the maximum translucent capacity of 200 mm of the lead at 1 m from the betatron target, the resolution of less than 1 mm, the gamma-pulse full width at half maximum of 100 ns in a single frame mode, the gamma-pulse full width at half maximum of 150 ns in a three-frame mode. The complex will be able to obtain up to 54 frames in one hydrodynamic experiment at the operation of each facility in a three-frame mode. The complex is compact. Its diameter with a service area will be 20 m.
* Pat. 2515053 С1 RU МPK G03B 42/02. Yu.P. Kuropatkin, others. «Method of Radiograph. Image Form. of Fast Processes in Inhomogeneity and Radiograph. Complex for its Implementation», 2014.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP027

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paper received ※ 25 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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THPMP033

Beam Characterisation Using MEDIPIX3 and EBT3 Film at the Clatterbridge Proton Therapy Beamline

proton, detector, simulation, radiation

3510

J.S.L. Yap, J. Resta-López, R. Schnuerer, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N.J.S. Bal
ASI, Amsterdam, The Netherlands
N.J.S. Bal, M. Fransen, F. Linde
NIKHEF, Amsterdam, The Netherlands
A. Kacperek
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
J.L. Parsons
Cancer Research Centre, University of Liverpool, Liverpool, United Kingdom
J. Resta-López, R. Schnuerer, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: EU FP7 grant agreement 215080, H₂020 Marie Skłodowska-Curie grant agreement No 675265 - Optimization of Medical Accelerators (OMA) project and the Cockcroft Institute core grant STGA00076-01.
The Clatterbridge Cancer Centre (CCC) in the UK is a particle therapy facility providing treatment for ocular cancers using a 60 MeV passively scattered proton therapy beam. A model of the beamline using the Monte Carlo Simulation toolkit Geant4 has been developed for accurate characterisation of the beam. In order to validate the simulation, a study of the beam profiles along the delivery system is necessary. Beam profile measurements have been performed at multiple positions in the CCC beam line using both EBT3 GAFchromic film and Medipix3, a single quantum counting chip developed specifically for medical applications, typically used for x-ray detection. This is the first time its performance has been tested within a clinical, high proton flux environment. EBT3 is the current standard for conventional radiotherapy film dosimetry and was used to determine the dose and for correlation to fluence measured by Medipix3. The count rate linearity and doses recorded with Medipix3 were evaluated across the full range of available beam intensities, up to 3.12 x 10¹⁰ protons/s. The applicability of Medipix3 for proton therapy dosimetry is discussed and compared against the performance of EBT3.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP033

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

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THPMP036

Beam Dynamics of Novel Hybrid Ion Mass Analysers

detector, target, site, injection

3522

R.B. Appleby, T. Rose
UMAN, Manchester, United Kingdom
M.R. Green, P. Nixon, K. Richardson
Waters Corporation, Manchester, United Kingdom

Fourier transform (FT) mass spectrometers achieve high resolution using relatively long transient times by trapping ions and measuring the frequency of their motion (inductively) inside an electrostatic potential. By contrast, time-of-flight (ToF) mass spectrometers measure the time of flight between an initiation pulse and contact with a destructive detector positioned on a plane of space focus after flying along a predetermined route. These devices have relatively short flight times and, generally, lower resolution. A class of hybrid analysers have been proposed and studied, utilising a quadro-logarithmic potential to reflect ions multiple times past an inductive detector, with the potential for the short transient of ToF devices - and the high resolution of FT devices. In this paper we compute the ion dynamics inside such devices, tracking bunches of ions and studying induced signals.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP036

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

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THPMP041

A Comparative Study of Biological Effects of Electrons and Co-60 Gamma Rays on pBR322 Plasmid DNA

radiation, electron, controls, proton

3533

K.L. Small, R.M. Jones
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, M. Surman
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Chadwick, N.T. Henthorn, K. Kirkby, M.J. Merchant, R. Morris, E. Santina
The Christie NHS Foundation Trust, Manchester, United Kingdom
R. Edge
Dalton Cumbrian Facility, University of Manchester, Cumbria, United Kingdom
R.J. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Very High-Energy Electron (VHEE) therapy is a rapidly developing field motivated by developments in high-gradient linacs. Advantages include sufficient penetration (>30 cm) for treatment of deep-seated tumours, measured insensitivity to inhomogeneities and rapid delivery time, making VHEE viable for treatment of heterogeneous regions, e.g. lung or bowel. Researchers at the University of Manchester and CERN have routinely produced accelerating gradients of ~100 MeV/m for the CLIC project. Suitable modification can result in a high gradient medical linac producing 250 MeV electrons within a treatment room. Radiobiological research for VHEE is vital to understand its use in radiotherapy and how it compares with conventional modalities. The goal of radiotherapy is to destroy tumour cells while sparing healthy cells, primarily by damaging DNA within the cancer cell. The study aim is to understand the fundamental interactions between VHEE and biological structures through plasmid irradiation studies - both computational, using the Monte Carlo GEANT4-DNA code, and experimental. Plasmid irradiation experiments have been carried out at using Co-60 gammas at the Dalton Cumbrian Facility and using 6-15 MeV electrons at the Christie NHS Foundation Trust to determine the type and quantity of damage caused to DNA by electron irradiation. These experiments are a world first in VHEE radiobiology, with further studies planned at higher energies using the CLARA and CLEAR facilities at Daresbury and CERN. These studies will also consider the effective dose range of VHEE with energy, as well as implications of damage on DNA. Research into this area of radiotherapy can provide a valuable addition to tools currently available to physicians in the fight against cancer.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP041

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

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THPMP043

Non-Invasive Beam Monitoring Using LHCb VELO With 40 MeV Protons

detector, proton, cyclotron, monitoring

3541

R. Schnuerer, C.P. Welsch, J.S.L. Yap, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T. Price
Birmingham University, Birmingham, United Kingdom
R. Schnuerer, C.P. Welsch, J.S.L. Yap, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
T. Szumlak
AGH, Cracow, Poland

Funding: EU grant agreements 215080 and 675265, the Cockcroft Institute core Grant (ST/G008248/1), national agency: MNiSW and NCN (UMO-2015/17/B/ST2/02904) and the Grand Challenge Network+ (EP/N027167/1).
In proton beam therapy, knowledge of the detailed beam properties is essential to ensure effective dose delivery to the patient. In clinical practice, currently used interceptive ionisation chambers require daily calibration and suffer from slow response time. This contribution presents a new non-invasive method for dose online monitoring. It is based on the silicon multi-strip sensor LHCb VELO (VErtex LOcator), developed originally for the LHCb experiment at CERN. The semi-circular detector geometry offers the possibility to measure beam intensity through halo measurements without interfering with the beam core. Results from initial tests using this monitor in the 40 MeV proton beamline at the University of Birmingham, UK are shown. Synchronised with an ionisation chamber and the RF cyclotron frequency, VELO was used as online monitor by measuring the intensity in the proton beam halo and using this information as basis for 3D beam profiles. Experimental results are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP043

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

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THPMP053

Tuning Quadrupoles for Brighter and Sharper Ultra-fast Electron Diffraction Imaging

quadrupole, electron, focusing, solenoid

3571

X. Yang, L. Doom, M.G. Fedurin, Y. Hidaka, J.J. Li, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, G.M. Wang, L.-H. Yu, Y. Zhu
BNL, Upton, Long Island, New York, USA
W. Wan
ShanghaiTech University, Shanghai, People’s Republic of China

Funding: BNL LDRD
We report our proof-of-principle design and experi-mental commissioning of broadly tunable and low-cost transverse focusing lens system for MeV-energy electron beams at the ultra-fast electron diffraction (UED) beam-line of the Accelerator Test Facility II of BNL. We exper-imentally demonstrate the independent control over the size and divergence of the electron beam at the sample via tunable quadrupoles. By applying online optimiza-tion, we achieve minimum beam sizes 75 µm from 1 to 13 pC, two orders of magnitude higher charge density than previously achieved using conventional solenoid tech-nique. Finally, we experimentally demonstrate Bragg-diffraction image (BDI) with significant improvement up to 3 times brighter and 2 times sharper BDI peaks via the optimized quadrupoles, improvement larger with higher charge. The result could be crucial for the future single-shot ultra-fast electron microscope development.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP053

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

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THPGW001

Design of LhARA - Laser Hybrid Accelerator for Radiobiological Applications

proton, laser, focusing, target

3578

J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
O. Ettlinger, C. Hunt, A. Kurup, K.R. Long, Z. Najmudin, J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
H.T. Lau
EBG MedAustron, Wr. Neustadt, Austria

Recent developments of using lasers interacting with targets for the creation of ion beams offer a possibility to provide beams for radiobiology research. This research aims to precisely study the radiobiological effectiveness of charged particles on various cultures of cells, which is essential to inform next generation hadron therapy treat-ment plans. The Laser hybrid Accelerator for Radiobio-logical Applications (LhARA) has been proposed to use a laser driven beam, which will be captured and focused using Gabor Lenses. The beam will be then energy and momentum selected to create a beam for in-vitro cells studies or sent to a post-accelerator ring to create beam for in-vivo studies. The optical design of LhARA is pre-sented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW001

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

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THPGW015

Proposed Beam Test of a Transverse Gradient Undulator at the SINBAD Facility at DESY

undulator, linac, electron, radiation

3609

R. Rossmanith, A. Bernhard, K. Damminsek, J. Gethmann, S. Richter
KIT, Karlsruhe, Germany
R.W. Aßmann, F. Burkart, U. Dorda, F. Jafarinia, B. Marchetti
DESY, Hamburg, Germany
M. Kaluza
IOQ, Jena, Germany

While Laser Plasma Accelerators produce beams with the high output energy required for FELs, up to now the relatively high energy spread has prohibited FEL lasing. Therefore it was proposed to replace the normal FEL undulators by Transverse Gradient Undulators (TGUs). For a first, small scale test of the TGU concept, a 40 period prototype high gradient superconductive TGU was built at KIT and will be tested with beam at the ARES-linac in the new accelerator test facility SINBAD (Short Innovative Bunches and Accelerators at Desy) at DESY. The proposed tests are summarized in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW015

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paper received ※ 07 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPGW016

Overview and Prospects of Plasma Wakefield Acceleration Experiments at PITZ

plasma, electron, wakefield, laser

3612

O. Lishilin, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, F. Stephan
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann, A. Martinez de la Ossa, J. Osterhoff
DESY, Hamburg, Germany
F.J. Grüner
Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany
T.J. Mehrling, C.B. Schroeder
LBNL, Berkeley, USA

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) carries out studies of beam-driven plasma wakefield acceleration (PWFA). The facility possesses a flexible photocathode laser beam shaping system and a variety of diagnostics including a high-resolution dipole spectrometer and an rf deflector which enables the observation of the longitudinal phase space of electron beams after their passage through a plasma. Two plasma sources are available: a gas discharge plasma cell and a photoionized lithium vapor plasma cell. Studies at PITZ include investigations of the self-modulation instability of long electron beams and the high transformer ratio, i.e., the ratio between the maximum accelerating field behind the drive beam and the decelerating field within the beam. This overview includes the experimental results and plans for future experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW016

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

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THPGW024

Beam-based Alignment at the Cooler Syncrotron (COSY)

quadrupole, dipole, alignment, synchrotron

3632

T. Wagner, J. Pretz
FZJ, Jülich, Germany

There is a matter-antimatter asymmetry observed in the universe that can not be explained by the Standard Model of particle physics. To resolve that problem additional CP violating phenomena are needed. A candidate for an additional CP violating phenomenon is a non-vanishing Electric Dipole Moment (EDM) of subatomic particles. Since permanent EDMs violate parity and time reversal symmetries, they also violate CP if the CPT-theorem holds. The Jülich Electric Dipole moment Investigation (JEDI) Collaboration works on a direct measurement of the electric dipole moment (EDM) of protons and deuterons using a storage ring. The JEDI experiment requires a small beam orbit RMS in order to measure the EDM. Therefore an ongoing upgrade of the Cooler Syncrotron (COSY) is done in order to improve the precision of the beam position. One of part of this upgrade is to determine the magnetic center of the quadrupoles with respect to the beam position monitors. This can be done with the so called beam-based alignment method. The first results of the beam-based alignment measurement performed in February 2019 will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW024

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

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THPGW035

Development of Yb-Based Laser System for Crab Crossing Laser-Compton Scattering

laser, electron, luminosity, scattering

3657

R. Morita, Y. Koshiba, S. Ota, M. Washio
Waseda University, Tokyo, Japan
T. Higashiguchi
Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
K. Sakaue
The University of Tokyo, The School of Engineering, Tokyo, Japan
J. Urakawa
KEK, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI 18H0123.
We are going to demonstrate the principle of crab crossing in laser-Compton scattering which creates head-on collision in a pseudo manner to enhance the intensity of laser-Compton X-ray. When the electron beam is tilted by half of the collision angle, the scat-tered X-rays becomes the largest. Calculation shows that more than threefold luminosity will be achieved in our system and could be larger luminosity depending on the beam parameters. The intensity of scattered light can be efficiently enhanced by using a collision laser with high intensity, high quality and ultrashort pulse duration. Thus, we have introduced a regenera-tive amplifier using ceramics thin-disk as a collision laser and developed a dedicated laser system. In this conference, we will report on our laser system and results of crab crossing laser-Compton scattering.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW035

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

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THPGW036

Development of Supercontinuum Light Production System Using Er Fiber Laser for Pulse Radiolysis*

laser, radiation, electronics, electron

3660

T. Uchida, S. Hanai, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

Pulse radiolysis is one of the methods to elucidate radiation chemical reactions. In order to elucidate that, not only high temporal resolution, but also a light source with a broad spectrum band is required. A Xe flash lamp is mentioned as a light source having a broad spectrum band. However, in measurement using a Xe flash lamp, the time resolution is limited to the nanosecond order. In this research, we have developed supercontinuum light as a light source that enables picosecond time resolution and has a broader spectrum band. In this paper, we developed a light source using an Er doped fiber laser for pulse radiolysis measurement, and report the results and future prospects here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW036

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paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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THPGW039

Moderation of Positive Muons by Helium Gas

proton, simulation, scattering, vacuum

3667

Y. Li, Y. Bao, R. Fan, X. Li, X. Tong
IHEP, Beijing, People’s Republic of China
C.J. Ning, P.C. Wang
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work is supported by CAS, National Natural Science Foundation of China (Grant No. 11875281), and China Postdoctoral Science Foundation (Grant No. 2019M650845)
Efficiently creating beams of spin-polarized positive muons with energies between eV and keV (so-called slow muon beams) is important for further development and application of muon spin rotation, relaxation, and resonance techniques. One existing moderation method involves the use of wide-band-gap materials as moderators such as rare gas solids and solid nitrogen thin films (band-gap energy between 11 eV and 22 eV). Based on this moderation method, we have studied the use of helium gas as a moderator, with the goal of producing the slow muon beam more efficiently. Because of helium’s high (24.6 eV) ionization energy and because the cross section for muonium formation is suppressed in helium gas, we expect the production of slow muons using helium gas to be highly efficient.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW039

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

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THPGW041

The Potential of Heavy Ion Beams to Provide Secondary Muon/Neutrino Beam

target, heavy-ion, proton, solenoid

3673

H.-J. Cai, L.W. Chen, L. Yang, S. Zhang
IMP/CAS, Lanzhou, People’s Republic of China

This paper focuses on the exploration into the potential of heavy ion beams for the production of the charged pions/muons within different energy ranges which is widely needed for fundamental and applied research. The investigation is performed for the different kinds of beams involving 1H , 4He, 12C, 16O, 40Ar and 136Xe with medium energy within the range of 0.5~2.5 AGeV and high energy of 10 AGeV. Three kinds of typical target configurations, thin graphite plate, long tungsten rod and medium thickness nickel block are adopted. For comparison, graphite and nickel are also used for the long rod geometry. Basically, most of the conventional charged pion/muon beams production cases including surface muon, low energy decay muon, medium energy pion/muon for neutrino beam and highly forward energetic muon are involved and the feasibility of heavy ion beam for these cases is analyzed.

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

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THPGW044

Highly Stable Linearly Polarized Arbitrary Temporal Shaping of Picosecond Laser Pulses

laser, controls, polarization, flattop

3682

F. Liu, S. Huang, K.X. Liu
PKU, Beijing, People’s Republic of China
S. Zhang
JLab, Newport News, Virginia, USA

This paper reports the study and demonstration of a new variable temporal shaping method capable of generating linearly polarized picosecond laser pulses with arbitrary predefined shapes, which are highly desired by various applications including low emittance high brightness electron bunch generation in photocathode guns. It is found that both high transmittance and high stability of the shaped pulses can be achieved simultaneously when crystals are set at specific phase delay through the fine control of the crystal temperature. Such variable temporal shaping technique may lead to new opportunities for many potential applications over a wide range of laser wavelengths, pulse repetition rates, time structures and power levels, etc. In addition, a new double-pass variable shaping method is also proposed and could significantly simplify the shaper structure and reduce the cost.
*liu_fangming@pku.edu.cn

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

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THPGW053

Exploiting the Potential of ISOLDE at CERN (the EPIC Project)

ISOL, target, storage-ring, proton

3706

R. Catherall, T.J. Giles, G. Neyens
CERN, Geneva, Switzerland

The ISOLDE Facility at CERN * is the world’s leading facility for the production of radioactive ion beams (RIBs) using the ISOL (Isotope Separation On-Line) method, providing RIBs at energies from 30 keV to 10 MeV/u for a wide variety of experiments. To improve on its capacity to deliver RIBs further from stability, the EPIC project takes full advantage of recent investments by CERN to upgrade the LHC injectors **. In particular, the new Linac4 and the PS Booster upgrade allow expanding the scope of ISOLDE by providing higher radioactive ion beam intensities further from stability. Sharing the proton-beam between two target stations that simultaneously feed the low-energy and high-energy beam lines will more than double the annual available beam time for experiments. To take further advantage of enhanced beam time, CERN and the ISOLDE collaboration also aims to studies installing a storage ring behind the HIE-ISOLDE post-accelerator to allow the storage of cooled exotic ion beams and thus opening up new possibilities in the fields of astrophysics, fundamental symmetry studies, atomic physics and nuclear physics.
* B. Jonson, K. Riisager (2010), Scholarpedia, 5(7):9742 doi:10.4249/scholarpedia.9742
** K. Hanke et al.DOI: 10.18429/JACoW-IPAC2017-WEPVA036

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

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THPGW055

Improving High Precision Cam Mover’s Stiffness

FEM, alignment, interface, collider

3713

J. Kemppinen
ETH, Zurich, Switzerland
H.M. Durand, A. Herty
CERN, Meyrin, Switzerland

Pre-alignment is a key challenge of the Compact Linear Collider (CLIC) study. The requirement for CLIC main beam quadrupole (MBQ) alignment is positioning to within 1 µm from target in 5 degrees of freedom (DOF) with ± 3 mm travel. After motion, the position should be kept passively while the system’s fundamental frequency is above 100 Hz. Cam movers are considered for the task. Traditionally they are used for the alignment of heavier magnets with lower accuracy and stiffness requirement. This paper presents a new CLIC prototype cam mover with design emphasis on the fundamental frequency. A finite element method (FEM) model predicts the mode shapes and eigenfrequencies of the system and can be used for further improving the design. Experimental modal analysis (EMA) of the prototype shows that the prototype’s fundamental frequency is at 44 Hz. It also validates the FEM model.
Juha. Kemppinen@cern.ch

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW055

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

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THPGW061

The K12 Beamline for the KLEVER Experiment

target, photon, detector, background

3726

M.W.U. Van Dijk, D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, N. Doble, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.S. Rosenthal, B. Veit
CERN, Geneva, Switzerland
G. D’Alessandro
JAI, Egham, Surrey, United Kingdom
M. Moulson
INFN/LNF, Frascati, Italy

The KLEVER experiment is proposed to run in the CERN ECN3 underground cavern from 2026 onward. The goal of the experiment is to measure BR(KL -> pi0 nu nu), which could yield information about potential new physics, by itself and in combination with the measurement of BR(K+ -> pi+ nu nu) of NA62. A full description will be given of the considerations in designing the new K12 beamline for KLEVER, as obtained from a purpose made simulation with FLUKA. The high intensities required by KLEVER, 2·10¹³ protons on target every 16.8s, with 5·10¹⁹ protons accumulated over 5~years, place stringent demands on adequate muon sweeping to minimize backgrounds in the detector. The target and primary dump need to be able to survive these demanding conditions, while respecting strict radiation protection criteria. A series of design choices will be shown to lead to a neutral beamline sufficiently capable of suppressing relevant backgrounds, such as photons generated by pi0 decays in the target, and Lambda -> npi0 decays, which mimic the signal decay.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW061

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

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THPGW063

The "Physics Beyond Colliders" Projects for the CERN M2 Beam

radiation, optics, hadron, detector

3734

D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.S. Rosenthal, M.W.U. Van Dijk, B. Veit, V. de Jesus
CERN, Geneva, Switzerland
S. Cholak
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
G. D’Alessandro
JAI, Egham, Surrey, United Kingdom

Physics Beyond Colliders is an exploratory study aimed at exploiting the full scientiﬁc potential of CERN’s accelerator complex up to 2040 and its scientiﬁc infrastructure through projects complementary to the existing and possible future colliders. Within the Conventional Beam Working Group (CBWG), several pro-jects for the M2 beam line in the CERN North Area were proposed, such as a successor for the COMPASS experiment, a muon programme for NA64 dark sector physics, and the MuonE proposal aiming at investigating the hadronic contribution to the vacuum polarisation. We present integration and beam optics studies for 100-160 GeV/c muon beams as well as an outlook for improvements on hadron beams, which include RF-separated options and low-energy antiproton beams and radiation studies for high intensity beams. In addition, necessary beam instrumentation upgrades for beam particle identiﬁcation and momentum measurements are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW063

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

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THPGW064

Commissioning Results of the Tertiary Beam Lines for the CERN Neutrino Platform Project

MMI, target, positron, simulation

3738

M.S. Rosenthal, N. Charitonidis, E.M. Nowak, I. Ortega Ruiz
CERN, Geneva, Switzerland
A.C. Booth
University of Sussex, Brighton, United Kingdom
Y. Chatzidaki
National Technical University of Athens, Zografou, Greece
Y. Karyotakis
IN2P3-LAPP, Annecy-le-Vieux, France
P.R. Sala
INFN-Milano, Milano, Italy

For many decades the CERN North Area facility at the Super Proton Synchrotron (SPS) has delivered secondary beams to various fixed target experiments and test beams. In 2018, two new tertiary extensions of the existing beam lines, designated "H2-VLE" and "H4-VLE", have been constructed and successfully commissioned. These beam lines have been designed to provide charged particles of both polarities in the momentum range from 0.3 GeV/c to 12 GeV/c. During the design phase, multiple simulation tools and techniques have been employed to optimize the tertiary beam line layout in terms of particle production, transverse beam dynamics and particle identification on an event-by-event basis. In this paper, a comparison of the simulated performance and the first measurement results obtained during the commissioning phase are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW064

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

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THPGW071

Genetic Optimisation of Beamline Design for DIAMOND

synchrotron, framework, photon, radiation

3753

F. Bakkali Taheri, M. Apollonio, R. Bartolini, B. Singh
DLS, Oxfordshire, United Kingdom
R. Bartolini, J. Li
JAI, Oxford, United Kingdom
R. Bartolini
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The problem of optimisation of beamline structures is studied, from the point of view of multi-objective genetic algorithms. While this approach has been successfully used in the exploration of potential particle accelerator lattices, it has never been applied to beamline design. In this paper, the Non-Dominated Sorting Genetic Algorithm II (NGSA II) is used to optimize a structure where photons are assumed to propagate through the optical elements according to the wavefront model as implemented in SRW. It is shown that appropriate objective functions can help to set up an interesting set of parameters, with competitive computational resources compared to the traditional approach. Examples illustrating this optimization method are shown in the context of DIAMOND.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW071

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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THPGW073

Status on a Laser Injection in Beam Driven Dielectric Wakefield Accelerator Experiment

wakefield, plasma, laser, electron

3761

G. Andonian, T.J. Campese, F.H. O’Shea
RadiaBeam, Santa Monica, California, USA
D.L. Bruhwiler, N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
T. Xu
Northern Illinois University, DeKalb, Illinois, USA

The generation of high-brightness beams with ultra-low emittance using the plasma photocathode technique has gained significant traction in recent years. The practical execution of a combined plasma wakefield acceleration section and a laser injected typically requires a dual gas medium for precision ionization of low and high ionization thresholds. The concept can be partially simplified in experiment by replacing the plasma wakefield acceleration component with a dielectric wakefield acceleration scheme, sacrificing field gradient but maintaining low emittance beam generation. In this paper, we describe the progress on the design of a hybrid scheme, using laser injection in a gas medium within a dielectric wakefield accelerator structure. The proof-of-concept experiment is planned to take place at the Argonne Wakefield Accelerator.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW073

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

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THPGW079

THz-Based Femtosecond MeV Electron Bunch Compression

electron, FEM, GUI, focusing

3766

M.A.K. Othman, M.C. Hoffmann, M.E. Kozina, R.K. Li, E.A. Nanni, X. Shen, E.J. Snively, X.J. Wang
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
Probing structural dynamics at atomic spatial and ultrashort temporal scales reveals unprecedented details of fundamental behavior of nature, allowing for better understanding of intricate energy-matter interaction occurring at such scales. Developing state-of-the-art technology to access these details entails utilizing X-ray free-electron lasers (XFELs), ultrafast electron diffraction (UED), and advanced electron microscopes. In particular, ultrafast diffraction science received growing attention thanks to innovation in sources, detectors and instrumentation in general. Within this context, interest in laser-generated THz wave-matter interaction has recently emerged as a new regime for controlling electrons with high temporal precision. Previously, the SLAC UED team has demonstrated attosecond electron metrology using laser-generated single-cycle THz radiation, which is intrinsically phase locked to the optical drive pulses, to manipulate multi-MeV relativistic electron beams. Here we demonstrate further steps towards achieving ultrafast timing resolution that utilizes femtosecond electron bunches. The proposed setup allows for compressing electron beam bunches down to a femtosecond using interaction with high field single-cycle THz pulses. We demonstrate a novel design of a dispersion-free parallel-plate tapered waveguide that provides focusing of THz pulses achieving >100 MV/m field strength at the interaction point as measured by electro-optical sampling for ~7 μJ of incoming THz pulse energy. The structure is being designed and built for bunch compression experiments using the SLAC UED facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW079

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

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THPGW080

Initial Results of High-Gradient Breakdown Tests for W-Band Accelerating Structures

cavity, electron, laser, vacuum

3769

M.A.K. Othman, V.A. Dolgashev, A.A. Haase, E.A. Nanni, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
S. Jawla, J.F. Picard, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
S.C. Schaub
MIT, Cambridge, Massachusetts, USA
B. Spataro
INFN/LNF, Frascati, Italy

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515 (SLAC) and grant DE-SC0015566 (MIT). This work was also supported by NSF grants PHY-1734015.
Emerging accelerator technology at mm-wave and THz frequencies has recently shown notable progress. Indeed, metallic and dielectric accelerating structures at THz frequencies are plausible candidates toward miniaturization of accelerators. RF breakdown in such structures is a major factor limiting their performance. Therefore, comprehensive analysis of RF breakdown physics in mm-wave accelerating structures is needed, which includes understanding of dependencies of the breakdown rate on geometric, electromagnetic and material properties. In this work we report on high power tests of a 110 GHz single-cell standing wave accelerating structure powered by a 1 MW gyrotron. The RF power is coupled from the gyrotron into the accelerating structure with a Gaussian to TM01 mode converter through a quasi-optical setup. We demonstrate coupling of 10 ns, 100s of kilowatt pulses into the structure using a fast switch and achieving ~150 MV/m accelerating gradients. Measurements of RF signals and field-emitted currents allow for complete comprehensive of the high-gradient behavior of W-band structures, including breakdown probability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW080

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

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THPGW088

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

plasma, wakefield, emittance, acceleration

3778

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

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

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW088

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

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THPRB019

Collimation of Target Induced Halo Following MAGIX at MESA

target, simulation, beam-losses, cryomodule

3839

B. Ledroit
IKP, Mainz, Germany
K. Aulenbacher
KPH, Mainz, Germany
K. Aulenbacher
GSI, Darmstadt, Germany
K. Aulenbacher
HIM, Mainz, Germany

Funding: Supported by the DFG through GRK 2128
The Mainz Energy-recovering Superconducting Accelerator (MESA) will be an electron accelerator allowing operation in energy-recovery linac (ERL) mode. It provides the opportunity to operate scattering experiments at energies of ~100 MeV with thin gas-targets. The MESA Internal Gas Target Experiment (MAGIX) aims to operate windowless jet targets and different gases up to Xenon to search for possible dark photon interactions, to precisely measure the magnetic proton radius and astrophysical S-factors. Investigations on the impact of the target on beam dynamics and beam losses are required for machine safety and to examine limits to ERL operation. The goal of this work is to understand target induced halo in the different experimental setups, track halo particles through downstream sections to examine beam losses and include a suitable collimation system and shielding into the accelerator layout to protect the machine from direct and indirect damage through beam losses and radiation. The present status of the investigations is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB019

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

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THPRB023

An MTCA.4 Based Position Feedback Application Using Laserinterferometers

laser, controls, feedback, interface

3853

K.P. Przygoda, L. Butkowski, S. Pfeiffer, H. Schlarb, P. Wiljes
DESY, Hamburg, Germany

To perform experiments on the nanometer scale at high brilliant x-ray light sources, it is highly recommended to have the mechanical components of the experiment, like lenses, mirrors and samples, as stable as possible. Since these components need to move from nanometer up to millimeter range they cannot be stabilized by only using rigid structures. For that reason an active stabilization system with fast and precise sensors needs to be developed. Here a Laserinterferometer is used, which provides picometer resolution at several MHz sample rate. In this paper we will present a laboratory setup which consists of a 6-slot Micro Telecommunication Computing Architecture generation 4 (MTCA.4) crate with standard components such MicroTCA carrier hub (MCH), central processing unit (CPU), power supply (PS) and cooling unit (CU). The Interferometer application has been setup with Deutsches Elektronen-Synchrotron (DESY) advanced mezzanine card (DAMC-FMC20) data processing unit, DESY Field Programmable Gate Array (FPGA) mezzanine card (DFMC-UNIO) universal input and output extension and DESY rear transition module (DRTM-PZT4) piezo driver. The encoder signals given by the interferometer controller are processed within the FPGA and then forwarded to the piezo amplifier RTM-board. The signal processing application includes decoding the digital feedback signal, calculating the coordinate transform for specific experimental setups and closed-loop operation based on a proportional integral derivative (PID) controller. The first results of the laboratory setup are demonstrated and briefly discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB023

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB028

Redesign of the JavaFX Charts Library in View of Real-Time Visualisation of Scientific Data

interface, controls, real-time, framework

3868

R.J. Steinhagen, H. Bräuning, A. Krimm, T. Milosic
GSI, Darmstadt, Germany

The accurate graphical representation of accelerator- or beam-based parameters is crucial for commissioning and operation in any modern accelerator. Charts are one of the most visible but at the same time often underappreciated accelerator control system components even though these are crucial for easing and improving a quick intuitive understanding of complex or large quantities of data, which in turn is used to efficiently control, troubleshoot or improve the accelerator performance. While the Java SDK and other third-party libraries provide some charting components, we found that these lack either functionality, performance, or are based on outdated complex APIs. Based on earlier GSI and CERN designs and careful analysis of missing functionalities, performance bottlenecks, and long-term maintenance risks for the necessary workarounds, we decided that it was worth to re-engineer a new scientific charting library that preserves the functionality of established other libraries while addressing the performance bottlenecks and APIs issues. The new library offers a wide variety of plot types common in the scientific community, a flexible plugin system to extend the functionality towards chart interactors as well as online parameter measurements commonly found in oscilloscopes. Tailored towards high performance, it achieves real-time update rates up to 25 Hz for data sets with a few 10k up to 5 million data points. The new API shields the complexity from and eases the library’s use by normal users, while still being modular and having explicitly open interfaces that allow more-inclined developers to modify, add or extend missing functionalities. This contribution provides a performance and functionality comparison with other existing Java-based charting libraries.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB028

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

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THPRB031

Operational Performance of the Machine Protection Systems of the Large Hadron Collider During Run 2 and Lessons Learnt for the LIU/HL-LHC Era

operation, machine-protect, injection, optics

3875

M. Zerlauth, A. Antoine, W. Bartmann, C. Bracco, E. Carlier, Z. Charifoulline, R. Denz, B. Goddard, A. Lechner, N. Magnin, C. Martin, R. Mompo, S. Redaelli, I. Romera, B. Salvachua, R. Schmidt, J.A. Uythoven, A.P. Verweij, J. Wenninger, C. Wiesner, D. Wollmann, C. Zamantzas
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) has successfully completed its second operational run of four years length in December 2018. Operation will be stopped during two years for maintenance and upgrades. To allow for the successful completion of the diverse physics program at 6.5 TeV, the LHC has been routinely operating with stored beam energies close to 300 MJ per beam during high intensity proton runs as well as being frequently reconfigured to allow for special physic runs and important machine developments. No significant damage has incurred to the protected accelerator equipment throughout the run thanks to the excellent performance of the various machine protection systems, however a number of important observations and new failure scenarios have been identified, which were studied experimentally as well as through detailed simulations. In this contribution, we provide an overview of the performance of the machine protection systems throughout Run 2 as well as the important lessons learnt that will impact consolidation actions and the upgrade of the machine protection systems for the LIU/HL-LHC era.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB031

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

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THPRB041

Design a Precise Stability Controller for High Power Pulse Modulator Based on FPGA

controls, FEL, FPGA, linac

3900

Y.F. Liu, Z.H. Chen, M. Gu, J. Tong, Y. Wu, Q. Yuan, X.X. Zhou
SINAP, Shanghai, People’s Republic of China

Shanghai Soft X-ray Free Electron Laser (SXFEL) facility is under testing at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences. The stability of RF system is one of the major factors to get great beam performance. It is mainly determined by klystron modulators power supply. The beam voltage of the LINAC klystron modulator, which is the pulsed power source of the RF amplifier, is directly affecting the RF amplitude and phase. This paper shows the suitable upgrade scheme of the modulator power supply and design considerations for the stability improvement of modulator power supply for Shanghai SXFEL. We present a real time feedback control system of LINAC pulse modulator to improve pulse to pulse amplitude stability. The feedback control system is based on the principle of embedded FPGA techniques. The control system consists of an embedded NIOS II processor, a High resolution ADC and an upper computer. The NIOS II processor manage on chip FIFO, ADC, IRQ, and Ethernet. The relevant experiments indicate that the feedback control strategy reaches required function. It is useful to improve the stability of existing modulator power supply.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB041

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

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THPRB045

A Novel Microwave Switch-Based LLRF System for Long-Term System Phase Drift Calibration

LLRF, controls, coupling, ISOL

3915

Z.Y. Lin, Y.-C. Du, W.-H. Huang, C.-X. Tang, J. Tang
TUB, Beijing, People’s Republic of China
G. Huang, Y.L. Xu
LBNL, Berkeley, California, USA
Z. Sun, D. Zhang
HZCY Technologies Co., Ltd., Beijing, People’s Republic of China

The long-term phase drift is one of the important issue for the stability of the Low level RF system. The signal crosstalk and temperature effect on the RF field detectors will significantly limited the performance of the phase detecting precise and the phase locking. A novel micro-wave switch-based LLRF system has been developed in Tsinghua accelerator lab. The microwave switch are ap-plied to in the chopper circuit to turn continuous signal into pulse signal in the time domain to avoid the mutual signal interference. In this paper the LLRF system based on microwave switch is present. The preliminary long-term experiments result shows the phase stability can achieve about 50fs RMS slow drift; and the peak-to-peak value of the slow drift was (~2°C p-p) over 4 days.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB045

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

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THPRB046

The Preliminary Long-Term Slow Drift Calibration Study in Low-Level Rf System

LLRF, monitoring, timing, controls

3918

Z.Y. Lin, Y.-C. Du, W.-H. Huang, C.-X. Tang, J. Tang
TUB, Beijing, People’s Republic of China
G. Huang, Y.L. Xu
LBNL, Berkeley, California, USA
Z. Sun, D. Zhang
HZCY Technologies Co., Ltd., Beijing, People’s Republic of China

The phase drift of the RF signal in the low-level radio frequency (LLRF) system is observed in the long-term operation, which limits the performance and stability of the LLRF system. The long-term drift was reproduced in the lab. Its effect and sources of error were explored in the simple LLRF46 board and the simplest LLRF system. It is founded that the temperature will significantly lead to the phase distortion of the two signal channels, although with the same electron device. The distortion will finally cause the long-term drift with temperature floating. A fixed phase calibration signal (CAL signal) is applied to deal with the signal channels difference. The preliminary tests were conducted and the results were analysed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB046

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

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THPRB055

DAMAGE BEHAVIOR OF TUNGSTEN TARGETS FOR 6 MEV LINEAR ACCELERATORS

target, electron, ECR, controls

3934

Z.H. Wang, Z.N. Liu, J. Shi, H. Zha
TUB, Beijing, People’s Republic of China

The target in electron linear accelerator is subjected to high-frequency and intense thermal shocks. Elevated temperatures in the target may lead to target recrystallization, fatigue cracking, creep and vaporization. In this study, experiments were carried out to investigate the damage behaviour of tungsten targets in 6 MeV linear accelerators under pulsed electron beam. The results show that recrystallization occurs after loading 6 MeV electron beam with repetition frequency of 220 Hz, pulse width of 4μs and mean current of 151μA for 248 s. Deformation and cracking caused by recrystallization are observed on the surface of the target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB055

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

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THPRB056

Dose Measurement Experiments for Single and Composite Targets in 6 Mev Linear Accelerators

target, site, electron, simulation

3937

Z.H. Wang, J.Y. Liu, J. Shi, H. Zha
TUB, Beijing, People’s Republic of China

The target in electron linear accelerator plays an im-portant role in the production of photon. Targets of different materials and thicknesses have different X-ray yields. In this study, experiments were carried out to measure the dose rates of single targets and composite targets of different thicknesses for 6 MeV linear accel-erators utilizing ionization chamber. The electron ener-gy spectrum at the outlet of accelerating tube was de-tected with magnetic analyser. The experimental results show consistent rules with Monte Carlo simulations. Composite material target of 1.2 mm tungsten and 2 mm copper can deliver 1242 rad/min/100uA dose rate at 1 meter in front of the target. Dose rates of tungsten- rhenium alloy(74%W-26%rhenium) targets were exam-ined too.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB056

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

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THPRB083

Detailed Analysis Of The Baseline Dose Levels And Localized Radiation Spikes In The Arc Sections Of The Large Hadron Collider During Run 2

radiation, operation, ECR, monitoring

4009

K. Bilko, M. Brugger, R. Garcia Alia, F.J. Harden, Y. Kadi, O. Stein
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) has eight insertion regions (IRs) which house the large experiments or accelerator equipment. These IRs are interconnected with the arc sections consisting of a periodic magnet structure. During the operation of the LHC small amounts of the beam particles are lost, creating prompt radiation fields in the accelerator tunnels and the adjacent caverns. One of the main loss mechanisms in the LHC arc sections is the interaction of the beam particles with the residual gas molecules. The analysis of the dose levels based on the beam loss measurement data shows that the majority of the measurements have similar levels, which allow to define baseline values for each arc section. The baseline levels decreased during the years 2015, 2016 and stabilised in 2017 and 2018 at annual dose levels below 50 mGy, which can be correlated with the residual gas densities in the LHC arcs. In some location of the arcs radiation spikes exceed the base line by more than two orders of magnitude. In addition to the analysis of these dose levels, a novel approach of identifying local dose maxima and the main driving mechanisms creating these radiation spikes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB083

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

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THPRB085

HiRadMat: A Facility Beyond the Realms of Materials Testing

proton, radiation, target, instrumentation

4016

F.J. Harden, A. Bouvard, N. Charitonidis, Y. Kadi
CERN, Geneva, Switzerland

The ever-expanding requirements of high-power targets and accelerator equipment has highlighted the need for facilities capable of accommodating experiments with a diverse range of objectives. HiRadMat, a High Radiation to Materials testing facility at CERN has, throughout operation, established itself as a global user facility capable of going beyond its initial design goals. Pulsed high energy, high intensity, proton beams have been delivered to experiments ranging from materials testing, detector’s prototype validation, radiation to electronics assessment and beam instrumentation. A 440 GeV/c proton beam is provided directly from the CERN SPS. Up to 288 bunches/pulse at a maximum pulse intensity of 3.5 x 10¹³ protons/pulse can be delivered. Through collaborative efforts, HiRadMat has developed into a state-of-the-art facility with improved in situ measurement routines, beam diagnostic systems and data acquisition techniques, offered to all users. This contribution summarises the recent experimental achievements, highlights previous facility enhancements and discusses potential future upgrades with particular focus on HiRadMat as a facility open to novel experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB085

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paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB087

Study of the Energy Savings Resulting from the East Area Renovation

ECR, operation, power-supply, radiation

4023

B.LM. Lamaille, F. Dragoni, S. Evrard, F.J. Harden, E. Harrouch, M. Lazzaroni, R. Lopez, K.D. Papastergiou
CERN, Meyrin, Switzerland

CERN’s East Experimental Area, situated on the Swiss side of the Meyrin site, with its four beamlines, has served physics for more than 40 years. As the building and equipment are reaching their end of life, a thorough consolidation project has been initiated in order to pro-vide many more years of reliable operation. This article addresses the different proposed solutions to reduce significantly the energy consumption of the East Area. It outlines the methodology applied to estimate as precisely as possible the future attained energy savings, which will result in an estimated reduction of approximately 80% in electricity usage (from 11 GWh to 2 GWh per year) and of approximately 65% in gas usage for heating purpose (from 3 GWh to 1 GWh per year).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB087

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

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THPRB090

Laboratory Exhaust Gas Treatment Systems at TPS

controls, synchrotron, status, photon

4029

J.-C. Chang, W.S. Chan, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

There are three main laboratory exhaust gas treatment systems equipped at Taiwan Photon Source (TPS): acid/alkaline system for corrosive acids and alkalis, volatile solvents, and other hazardous chemicals; organic system for biological experiments; and general system for other gas. Gas is collected in hoods installed near the sources of contamination in laboratories. The contamination then is transported through duct to the gas treatment equipment installed outside of the TPS experimental hall.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB090

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paper received ※ 06 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS001

Development of Cryogenic Suspension in the ANU 8t Superconducting Solenoid With Iron Yoke

solenoid, vacuum, cryogenics, EPICS

4103

S.T. Battisson, N.R. Lobanov, D. Tsifakis, T.B. Tunningley
Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
J.F. Smith
University of Surrey, Department of Physics, Guildford, United Kingdom

Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism.
An 8 Tesla superconducting solenoid was commissioned at The Australian National University to make precision measurements of fusion cross-sections. Forces between the solenoid and the iron yoke that houses it must always be maintained within safe limits and precision location of the solenoid coil is necessary to achieve this. Thermal contraction of components can impact the locating structure of the solenoid coil, leading to unsafe forces. Improvements to this structure allowed successful completion of the first fusion measurements with the 8T solenoidal separator, and demonstrated that it is now ready for a program of fusion measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS001

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

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THPTS009

High-Current Emittance Measurements at MAMI

emittance, quadrupole, electron, simulation

4121

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

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

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS009

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

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THPTS014

Visual Inspection of Curved Particle Accelerator Beam Pipes with a Modular Robot

controls, dipole, vacuum, simulation

4135

N. Schweizer
RMR, TU Darmstadt, Darmstadt, Germany
I. Pongrac
GSI, Darmstadt, Germany

Inspecting ultra-high vacuum pipe systems of particle accelerators without disassembling the beam pipes is a complex challenge. In particular, curved sections of particle accelerators require a unique approach for the examination of the interior. For the planned heavy ion synchrotron SIS100 at FAIR, an inspection robot is currently under development, featuring an optical imaging system with which the robot can be navigated through the beam pipe. We present the current prototype, which is based on a modular snake-like robot with active wheels and joints. Due to the stipulated low movement velocity, it can be shown that a kinematic model is sufficient to control the robot whereas dynamical effects can be neglected. This concept is proven in experiments with the prototype. At the current development status, the robot is controlled manually by setting the velocity of the first module and its desired turning angle. In simulations we include a CAD model of a dipole chamber of the SIS100 and let an operator successfully navigate the robot through the beam pipe while only observing the camera image.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS014

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

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THPTS022

The Realization of Iterative Learning Control for J-PARC LINAC LLRF Control System

controls, linac, LLRF, DTL

4155

S. Li
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Z. Fang, Y. Fukui, K. Futatsukawa, F. Qiu
KEK, Ibaraki, Japan
Y. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

The beam current of j-parc linac was planned to increase to 60 mA. The stronger beam current will lead to higher beam loading effect. Due to the low Q factor of cavity in high β section of linac, the traditional PID feedback & feedforward control method may have to face huge challenges. In order to make the system run better at 60 mA, the iterative learning control (ILC) method was put forward to use in LLRF control system. All the ILC operations are done in EPICS-PC. By installing the PyEpics module, we can use python programs to realize the data interaction between EPICS system and PC and further realize the ILC algorithm. In this paper, the architecture of ILC methods will be introduced. The performance of ILC method will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS022

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

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THPTS026

Effect of Nitric Hydrofluoric Acid Treatment on Brazing of Alumina Ceramics and Pure Titanium

vacuum, electron, controls, gun

4161

M. Kinsho, J. Kamiya
JAEA/J-PARC, Tokai-mura, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
T. Nakamura
Asahi Kinzoku Co., Ltd., Gifu, Japan

Alumina ceramics vacuum chamber which is used for the 3GeV rapid-cycling synchrotron (RCS) in J-PARC is composed of alumina duct, titanium (Ti) flanges and Ti sleeves. Before brazing the alumina duct and the Ti sleeves, the Ti sleeves were treated with nitric hydrofluoric acid. The purpose of this study is to clear the effect of this treatment for titanium material. It was cleared by SEM observation that the roughness of the titanium material after the nitric hydrofluoric acid treatment becomes big. It was also measured that the thickness of oxide film on surface of the titanium material was 12.7 nm before treatment and 6.0 nm after treatment. As a result of measuring the wettability of the brazing material which was silver brazing filler metal (Ag: 72%, Cu: 28%) on the Ti surface and the diffusion of the Ti material into the brazing material, it became clear that both the clearing of oxide layer on the alumina ceramics and the vacuum condition of the vacuum heating furnace were important for brazing between alumina ceramics and pure titanium.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS026

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

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THPTS031

Simulations of the Activation of a Proton Therapy Facility Using a Complete Beamline Model With BDSIM

simulation, proton, neutron, shielding

4176

R. Tesse, E. Gnacadja, C. Hernalsteens, N. Pauly
ULB - FSA - SMN, Bruxelles, Belgium
S.T. Boogert, L.J. Nevay, W. Shields
JAI, Egham, Surrey, United Kingdom
C. Hernalsteens
IBA, Louvain-la-Neuve, Belgium

A detailed model of the IBA Proteus One compact gantry system has been created with BDSIM (Beam Delivery Simulation) that has been validated against experimental data. Results regarding activation studies have been obtained for the first time using seamless simulations of the transport of protons in the beamline and their interactions with the environment. The activation of the concrete shielding of the system is estimated after a period of 20 years of operation. These main results are presented and discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS031

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

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THPTS037

The Deformation-Stress Simulation and Measurement of Titanium Foil Strip for Hadron Monitor

electron, simulation, hadron, ECR

4187

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

The measurement of beam profile by hadron monitor is in fact the measurement of the positive current after the secondary electrons escaped. According to the situation that the number of beam particles is small and the current signal is weak, the material titanium with high secondary electron generation rate is select by material comparison, and the foil strip type is used to increase the cross section area to obtain lager current level. On account of dead weight itself, as well as thermal expansion and contraction, the foil strip shall be loose. The loosen strip will deviate from its theoretical position, and cause the measuring error. Therefore, the deformation-stress of Ti foil strip (1000*50*0.1) was simulated under the pretension (10~90N) with the finite element software ANSYS. A set of experiment device with pretension adjustment and heating for the foil strip was designed, and then the deformation-stress was tested by a high precision 3-D imaging measurement system. Compared with the simulation results, the pretension would better set at about 50N.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS037

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paper received ※ 12 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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THPTS045

Preparation of Titanum-Zirconium-Vanadium Films by Quantitative Deposition

vacuum, electron, ECR, operation

4210

J.Q. Shao, C. Chen, X.Q. Ge, W. Li, S. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang, B.L. Zhu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

TiZrV has been used in vacuum technology and electric vacuum devices due to its high pumping speed and low activation temperature in recent years. At the same time, many preparation methods have been developed. Different from the current coating method of magnetron sputtering, this paper discusses the preparation of thin film coating from the viewpoint of vacuum sintering, which is flexible in design and more suitable for operation. Based on the analysis of the surface morphology of the sintered film, the feasibility and operability of the experimental method were explored from the surface compactness of the getter.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS045

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paper received ※ 25 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS053

Design of a Fast Cycled Low Loss 6 T Model Dipole Cooling at 1.9 K

dipole, synchrotron, superconducting-magnet, operation

4221

A.D. Kovalenko, V.A.. Gromov, E.E. Perepelkin, G. Shirkov
JINR, Dubna, Moscow Region, Russia
B. Bordini, D. Tommasini
CERN, Geneva, Switzerland
A. Kolomiets
ITEP, Moscow, Russia
S. Kozub, L. Tkachenko
IHEP, Moscow Region, Russia

The option being considered for the FCC-hh high energy injector is a superconducting synchrotron replacing the CERN SPS. The new machine would operate in a cycled mode also to feed experimental areas, much like the SPS nowadays. Due to this specific cycled operation, innovative design and development approaches is required to cope with the AC losses in the superconducting cables and iron yoke. The research joins experience accumulated at CERN and JINR respectively in the design and operation of large systems operated at 1.9 K and, in fast ramped and cycled magnets. The specified parameters are the following: magnet aperture -80 mm; aperture field - 6 T; field ramp 0.2-0.5 T/s; coil conductor - NbTi; magnetic field homogeneity between 0.12 and 6 T of the order of 5·10^-4. The minimization of the cycling losses is particular important. Total thermal losses should be limited to tentatively < 2 W/m at 4.2 K. The magnet design, and the results of preliminary tests on a candidate NbTi-wire for building a model magnet are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS053

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

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THPTS066

Beam Impact Experiment of 440GeV/p Protons on Superconducting Wires and Tapes in a Cryogenic Environment

proton, interface, simulation, cryogenics

4264

A. Will, A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany
Y. Bastian, B. Bordini, M. Favre, B. Lindstrom, M. Mentink, A. Monteuuis, A. Oslandsbotn, R. Schmidt, A.P. Siemko, K. Stachon, M.P. Vaananen, A.P. Verweij, A. Will, D. Wollmann
CERN, Geneva, Switzerland
M. Bonura, C. Senatore
UNIGE, Geneva, Switzerland
A. Usoskin
BRUKER HTS GmbH, Alzenau, Germany

The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failure cases. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, directly or via secondary particle showers. The interaction leads to energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb₃Sn strands as well as YBCO tape in a cryogenic environment to microsecond 440 GeV/p proton beams. The irradiated samples were extracted and are being analyzed for their superconducting properties, such as the critical transport current. This paper describes the experimental setup as well as the first results of the visual inspection of the samples.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS066

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

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THPTS067

Characterisation of the Radiation Hardness of Cryogenic Bypass Diodes for the HL-LHC Inner Triplet Quadrupole Circuit

radiation, neutron, quadrupole, luminosity

4268

D. Wollmann, C. Cangialosi, C. Cangialosi, F. Cerutti, G. D’Angelo, S. Danzeca, R. Denz, M. Favre, R. Garcia Alia, D. Hagedorn, A. Infantino, G. Kirby, L. Kistrup, T. Koettig, J. Lendaro, B. Lindstrom, A. Monteuuis, F. Rodriguez-Mateos, A.P. Siemko, K. Stachon, A. Tsinganis, M. Valette, A.P. Verweij, A. Will
CERN, Meyrin, Switzerland
A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany

Funding: Work supported by the HL-LHC Project.
The powering layout of the new HL-LHC Nb₃Sn triplet circuits is the use of cryogenic bypass diodes, where the diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to radiation. Therefore, the radiation hardness of different type of bypass diodes has been tested at low temperatures in CERN’s CHARM irradiation facility during the operational year 2018. The forward characteristics, the turn on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, respectively, as a function of the accumulated radiation dose. The diodes were submitted to a dose close to 12 kGy and a 1 MeV equivalent neutron fluence of 2.2x10¹⁴,n/cm². After the end of the irradiation campaign the annealing behaviour of the diodes was tested by increasing the temperature slowly to 300 K. This paper describes the experimental setup, the measurement procedure and discusses the results of the measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS067

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

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THPTS081

Novel Apparatus and Technique for Measuring RR Resistivity of Tube Coatings at Cryogenic Temperatures

cryogenics, lattice, cavity, vacuum

4304

A. Hershcovitch, J.M. Brennan, R. Than, S. Verdú-Andrés, Q. Wu
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A unique apparatus for measuring RF resistivity of tubes and coated tubes at cryogenic temperatures is operational at BNL, which to our knowledge is the first of its kind. A folded quarter wave resonator structure of 300 mm length accesses a wide range of frequencies. The structure is cooled in liquid He bath at 4 K. All internal resonator components (except for test samples) were fabricated out of superconducting materials. Consequently, when the resonator is cooled, the bulk of the losses are due to the copper coating. The RF resistivity is determined from Q measurements, since for a fixed geometry the quality factor of a resonant cavity is proportional to the square root of the conductivity. The RF input loop and the output signal antenna are adjustable when cold via bellows to control matching to each cavity mode. The Q values of 10 resonant modes between 180 and 2500 MHz are deduced from the bandwidth of the S21 response Network Analyzer measurements. CST MicroWave Studio is used to extract the resistivity of the samples from the Q measurements. Resistivity results of solid Cu tube, 2, 5, & 10 μm Cu coated 316LN stainless steel RHIC beam tubes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS081

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

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FRXXPLS1

Tests of a 3D Printed BPM with a Stretched Wire and with a Particle Beam

vacuum, pick-up, electron, instrumentation

4368

N. Delerue, D. Auguste, J. Bonis, F. Gauthier, S. Jenzer, A.M. Moutardier
LAL, Orsay, France

Funding: CNRS/IN2P3
We have successfully printed a beam position monitor using 3D printing. After ultra-high vacuum testing and initial measurements with a network analyser we now reports on tests of this BPM using the stretched wire method. The BPM has been installed on a test stand with a wire going through it and electrical pulses have been sent. The signal measured on the pick-ups was compared to that of two conventional BPMs and shows no anomaly specific to the 3D printed BPMs. Following the success of these tests we have also installed this BPM in a beam line at the PhotoInjector at LAL (PHIL). We show that it can give position measurements with an accuracy comparable to that of other BPMs.

Slides FRXXPLS1 [29.118 MB]

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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FRXXPLS2

Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET

proton, extraction, timing, kicker

4372

H. Nishiguchi, Y. Fukao, Y. Hashimoto, Y. Igarashi, S. Mihara, M. Moritsu, R. Muto, M. Tomizawa, K. Ueno
KEK, Tsukuba, Japan
Y. Fujii
Monash University, Faculty of Science, Clayton, Victoria, Australia
P. Sarin
Indian Institute of Technology Bombay, Mumbai, India
F. Tamura
JAEA/J-PARC, Tokai-mura, Japan

Funding: This work is partially supported by JSPS (Japan Society for the Promotion of Science) : KAKENHI 15K13492 and 16H00876
At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 10¹⁰ protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10⁻¹⁰ of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation.

Slides FRXXPLS2 [13.427 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS2

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

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