IPAC2019 - Classification: MC3: Novel Particle Sources and Acceleration Techniques / A22 Plasma Wakefield Acceleration

Paper	Title	Page
WEZPLS2	High Transformer Ratio Plasma Wakefield Acceleration Driven by Photocathode Laser Shaped Electron Bunches	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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZPLS2
About •	paper received ※ 21 May 2019 paper accepted ※ 29 May 2019 issue date ※ 21 June 2019
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WEZZPLS1	Experimental Demonstration of External Injection From a Linac into a LWFA with ~100% Capture Efficiency
	J.F. Hua, Y.C. Du, Y. Fang, S. Liu, W. Lu, C.H. Pai, B. Peng, Y.P. Wu, J. Zhang, Z. Zhou TUB, Beijing, People’s Republic of China
	Staging of conventional accelerators and advanced plasma-based accelerators can boost the beam energy while at the same time better control the beam quality, therefore it is essential for high-energy applications such as TeV-level colliders. Here we present the first successful demonstration of external injection from a linear accelerator (LINAC) into a laser wakefield accelerator (LWFA) and the subsequent acceleration with ~100% capture efficiency. Stable 31MeV, 20fC electron beams from the LINAC were velocity bunched to the length of ~15fs (r.m.s.) in the high-gradient photocathode RF gun and then external injected into the linear wakefield excited by the 10TW, 42fs laser. The experimental results show that nearly all the electrons can be mono-energetically accelerated and the maximum energy gain reaches 1.8MeV in a 6-mm long plasma, corresponding to an average gradient of about 300MV/m. High capture efficiency of external injection has also been systematically validated by 3D PIC simulations. This paves the way toward the development of high-energy particle accelerators for future colliders.
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WEZZPLS2	EuPRAXIA, a Step Toward a Plasma-Wakefield Based Accelerator With High Beam Quality	2291
	P.A.P. Nghiem, A. Chancé CEA-IRFU, Gif-sur-Yvette, France D. Alesini, E. Chiadroni, M. Croia, A. Del Dotto, M. Ferrario, A. Giribono, R. Pompili, S. Romeo, V. Shpakov, A. Stella, C. Vaccarezza INFN/LNF, Frascati, Italy A. Aschikhin, R.W. Aßmann, U. Dorda, A. Ferran Pousa, V. Libov, B. Marchetti, A. Martinez de la Ossa, D. Marx, P. Niknejadi, L. Schaper, E.N. Svystun, P.A. Walker, M.K. Weikum, J. Zhu DESY, Hamburg, Germany T. Audet, B. Cros, P. Lee, G. Maynard CNRS LPGP Univ Paris Sud, Orsay, France A. Beck, F. Massimo, A. Specka LLR, Palaiseau, France M. Chen, S.M. Weng Shanghai Jiao Tong University, Shanghai, People’s Republic of China A. Cianchi Università di Roma II Tor Vergata, Roma, Italy J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.-E. Couprie, A. Ghaith, D. Oumbarek Espinos SOLEIL, Gif-sur-Yvette, France G. Dattoli, F. Nguyen ENEA C.R. Frascati, Frascati (Roma), Italy N. Delerue LAL, Orsay, France R.A. Fonseca, L.O. Silva Instituto Superior Tecnico, Lisbon, Portugal L.A. Gizzi, G. Toci, P. Tomassini INO-CNR, Pisa, Italy A. Helm IST-UTL, Lisbon, Portugal B. Hidding Cockcroft Institute, Warrington, Cheshire, United Kingdom S.M. Hooker, R. Walczak Oxford University, Physics Department, Oxford, Oxon, United Kingdom M.G. Ibison, M. Vujanovic, C.P. Welsch, J. Wolfenden The University of Liverpool, Liverpool, United Kingdom D.A. Jaroszynski, F.Y. Li, Z.M. Sheng, S.M. Wiggins, S. Yoffe USTRAT/SUPA, Glasgow, United Kingdom K.O. Kruchinin, A.Y. Molodozhentsev ELI-BEAMS, Prague, Czech Republic L. Labate CNR/IPP, Pisa, Italy X. Li DESY Zeuthen, Zeuthen, Germany F. Mathieu LULI, Palaiseau, France Z. Mazzotta Ecole Polytechnique, Palaiseau, France T.J. Mehrling LBNL, Berkeley, USA A. Mosnier, C. Simon CEA, Gif-sur-Yvette, France A. Mostacci Rome University La Sapienza, Roma, Italy Z. Najmudin Imperial College of Science and Technology, Department of Physics, London, United Kingdom R. Pattathil, D. Symes STFC/RAL, Chilton, Didcot, Oxon, United Kingdom A.R. Rossi INFN-Milano, Milano, Italy T. Silva, J.M. Vieira IPFN, Lisbon, Portugal M.J.V. Streeter JAI, London, United Kingdom D. Terzani UniNa, Napoli, Italy
	Funding: European Union’s Horizon 2020 research and innovation programme under grant agreement No. 653782 The EuPRAXIA project aims at designing the world’s first accelerator based on plasma-wakefield advanced technique, which can deliver a 5 GeV electron beam with simultaneously high charge, low emittance and low energy spread to user’s communities. Such challenging objectives can only have a chance to be achieved when particular efforts are dedicated to identify the subsequent issues and to find the way to solve them. Many injection/acceleration schemes and techniques have been explored by means of thorough simulations in more than ten European institutes to sort out the most appropriate ones. The specific issues of high charge, high beam quality and beam extraction then transfer to the user’s applications, have been tackled with many innovative approaches. This article highlights the different advanced methods that have been employed by the EuPRAXIA collaboration and the preliminary results obtained. The needs in terms of laser and plasma parameters for such an accelerator are also summarized. - in 2017: Phys. Plasmas, 24,10,103120; Nat. Commun.8,15705; - in 2018: NIMA, 909,84-89; NIMA, 909,49-53; Phys. Rev.Acc. Beams, 21,111301; NIMA, 909,54-57; Phys. Rev.Acc. Beams, 21,052802; NIMA, 909,282-285
	Slides WEZZPLS2 [5.157 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZZPLS2
About •	paper received ※ 12 April 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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THPGW002	A Passive Plasma Beam Dump Study with Application to EuPRAXIA	3581
	R.P. Nunes UFRGS, Porto Alegre, Brazil A. Bonatto University of Manchester, Manchester, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: The author R. P. Nunes acknowledges the financial support provided by FAPERGS. This work presents a study about a passive dumping scheme applied to the beam generated by the accelerator stage of the EuPraxia experiment. Particle-in-cell simulations have been carried out and its results are compared with analytical estimates, showing a reasonable agreement.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW002
About •	paper received ※ 05 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW003	Energy Loss of an Electron Beam with Gaussian Density Profile Propagating in a Passive Plasma Beam Dump	3584
	A. Bonatto University of Manchester, Manchester, United Kingdom R.P. Nunes UFRGS, Porto Alegre, Brazil G.X. Xia UMAN, Manchester, United Kingdom
	Funding: CNPq, and FAPERGS, from Brazil. A semi-analytical 1D model is derived for the total energy loss of an electron beam with Gaussian density profile undergoing a passive plasma beam dump. The model is compared to a previous one, obtained for a half-sine longitudinal density profile. It is shown that both models agree if the beam density profiles are properly matched, and if their sizes are small in comparison to the length of wakefield decelerating length. The beam energy obtained from both models is compared to 1D PIC simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW003
About •	paper received ※ 09 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPGW006	Avoiding Emittance Degradation When Transferring the Beam From and to a Plasma-Wakefield Stage	3594
	A. Chancé, P.A.P. Nghiem CEA-IRFU, Gif-sur-Yvette, France X. Li DESY Zeuthen, Zeuthen, Germany
	Funding: European Union’s Horizon 2020 research and innovation programme under grant agreement No. 653782. The plasma-wakefield acceleration technique is known to provide a very strong accelerating gradient (GV/m), up to three orders of magnitude higher than the conventional RF acceleration technique. The drawback is a relatively higher energy spread and especially a huge beam divergence at the plasma exit, leading to an irremediable and strong emittance degradation right after its extraction from the plasma for transferring it to an application or another plasma stage. In this article, we determine the criteria to be achieved so as to minimize this emittance growth after pointing out all the parameters involved in its mechanism. Then the plasma down ramp profile is studied in a typical configuration of the EuPRAXIA project at 5 GeV. It turns out that no specific profile is needed. For minimizing emittance growth at beam extraction, it is enough to optimize the ramp length so that the Twiss parameter γ is minimized. Finally the design of an optimal transfer line allows showing that the emittance growth can be contained to less than 10% in realistic conditions when transferring the beam to a free electron laser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW006
About •	paper received ※ 09 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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THPGW012	Wake-T: A Fast Particle Tracking Code for Plasma-Based Accelerators	3601
	A. Ferran Pousa, R.W. Aßmann, A. Martinez de la Ossa DESY, Hamburg, Germany A. Ferran Pousa University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The design and study of plasma-based accelerators relies typically on costly 3D Particle-In-Cell (PIC) simulations due to the complexity of the laser-plasma and beam-plasma interactions. However, under certain assumptions, more efficient and simple models can be implemented to describe the dynamics of the accelerated beams. Wake-T (Wakefield particle Tracker) is a new code for analytical and numerical particle tracking in plasma-based accelerators which is orders of magnitude faster than conventional PIC codes. This allows for fast parameter scans and is well suited for the initial design and optimization of these novel accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW012
About •	paper received ※ 24 April 2019 paper accepted ※ 21 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	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW015
About •	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	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW016
About •	paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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THPGW017	Self-Modulation Instability of Electron Beams in Plasma Channels of Variable Length	3616
	O. Lishilin, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, G. Loisch, 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 self-modulation instability (SMI) of long (in respect to the plasma wavelength) charged particle beams passing through plasma enables the use of currently existing high energy charged particle beams as drivers for plasma wakefield accelerators. At the Photo Injector Test facility at DESY in Zeuthen (PITZ) the SMI of electron beams is studied , . An enhanced experimental setup includes a plasma channel of variable length which allows to investigate in details the development stages of the SMI by measuring the instability growth rate and phase velocity as a function of propagation distance in the plasma. In this contribution we present the experimental setup improvements, first measurement results and supporting beam dynamics simulations. M. Gross, et al., Phys. Rev. Lett., vol. 120, p. 144802, 2018. ** G. Loisch, et al., Plasma Physics and Controlled Fusion, vol. 61(4), p. 045012, 2019
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW017
About •	paper received ※ 11 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPGW019	FLASHforward Findings for the EuPRAXIA Design Study and the Next-Generation of Compact Accelerator Facilities	3619
	P. Niknejadi, R.T.P. D’Arcy, J.M. Garland, J. Osterhoff, L. Schaper, B. Schmidt, G.E. Tauscher DESY, Hamburg, Germany M. Ferrario, S. Romeo INFN/LNF, Frascati, Italy C.A. Lindstrøm University of Oslo, Oslo, Norway T.J. Mehrling LBNL, Berkeley, USA
	FLASHForward, the exploratory FLASH beamline for Future-ORiented Wakefield Accelerator Research and Development, is a European pilot test bed facility for accelerating electron beams to GeV-levels in a few centimeters of ionized gas. The main focus is on the advancement of plasma-based particle acceleration technology through investigation of injection schemes, novel concepts and diagnostics, as well as benchmarking theoretical studies and simulations. Since the plasma wakefield will be driven by the optimal high-current-density electron beams extracted from the FLASH L-band Superconducting RF accelerator, FLASHForward has been in a unique position for studying and providing insight for the design study of next-generation light source and high energy physics facilities such as EuPRAXIA. Summary of these findings and their broader impact is discussed here. P. A. Walker, et. al., "Horizon 2020 EuPRAXIA design study," Journal of Physics Conference Series 874(1):012029, July 2017.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW019
About •	paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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THPGW022	The Effect of the Transverse Beam Jitter on the Accelerated Electron Beam Quality in a Laser-Driven Plasma Accelerator with External Injection at SINBAD for ATHENAe	3624
	E.N. Svystun, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	Laser plasma accelerators with external injection of an RF-generated electron beam, providing high accelerating field gradients and increased control over the electron beam injection process, are promising candidates for production electron beams matching the requirements of modern user-applications. The experiments are planned at the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility to test this acceleration technique in the context of the ATHENAe (Accelerator Technology HElmholtz iNfrAstructure) project. In this paper we present numerical studies on the effect of the transverse electron beam jitter on the final quality of a sub-femtosecond, 0.75 pC, 100 MeV electron beam accelerated to 1 GeV energy in the plasma wakefield driven by a 196 TW, 5 J laser pulse.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW022
About •	paper received ※ 07 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW023	Numerical Studies on Electron Beam Quality Optimization in a Laser-Driven Plasma Accelerator with External Injection at SINBAD for ATHENAe	3628
	E.N. Svystun, R.W. Aßmann, U. Dorda, B. Marchetti, A. Martinez de la Ossa DESY, Hamburg, Germany
	Nowadays the electron beams produced in plasma-based accelerators (PBAs) are of sufficient energy for multi-GeV applications. However, to allow PBAs to be usable for demanding applications such as Free-Electron Lasers, the quality and stability of plasma-accelerated beams have to be improved. We present numerical studies on accelera-tion of an RF-generated electron beam with a charge of 0.8 pC and initial mean energy of 100 MeV to GeV energies by a laser-plasma accelerator. This acceleration scheme is planned to be tested experimentally within the framework of the ATHENAe (Accelerator Technology HElmholtz iNfrAstructure) project at the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY, Hamburg. Electron beam injection, acceleration and extraction from the plasma are investigated through start-to-end 3D simulations. The effect of the injection phase on the accelerated beam quality is investigated through tolerance studies on the arrival-time jitter between the electron beam and the external laser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW023
About •	paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW025	Facility Considerations for a European Plasma Accelerator Infrastructure (EuPRAXIA)	3635
	P.A. Walker, R.W. Aßmann, U. Dorda, B. Marchetti, M.K. Weikum DESY, Hamburg, Germany E. Chiadroni, M. Ferrario INFN/LNF, Frascati, Italy A. Specka LLR, Palaiseau, France R. Walczak JAI, Oxford, United Kingdom
	Funding: This work was supported by the European Union‘s Horizon 2020 research and innovation programme under grant agreement No. 653782. EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) is a conceptual design study for a compact European infrastructure with multi-GeV electron beams based on plasma accelerators. The concept foresees two main experimental sites, one at INFN in Frascati and one at DESY in Hamburg. In Frascati, an RF injector based on S-band and X-band technology (electron energy up to 1 GeV) will be constructed and used as a drive beam for beam driven plasma acceleration (PWFA) with final electron beam energies up to 5 GeV. At DESY, the focus will be on laser driven plasma acceleration (LWFA) and an RF injector based on S-band technology (electron energy up to 240 MeV) or alternatively a plasma injector (electron energy up to 150 MeV) can be used before the beam is injected into the plasma accelerator for external LWFA and acceleration up to 5 GeV. A single stage approach based on LWFA with internal injection will also be pursued in a second beamline. User areas at both sites will provide access to FEL pilot experiments, positron generation, compact radiation sources, and test beams for HEP detector development. This contribution discusses facility space considerations for the future plasma accelerator research infrastructure of EuPRAXIA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW025
About •	paper received ※ 13 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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THPGW026	Status of the Horizon 2020 EuPRAXIA Conceptual Design Study	3638
	M.K. Weikum, A. Aschikhin, R.W. Aßmann, R. Brinkmann, U. Dorda, A. Ferran Pousa, T. Heinemann, F. Jafarinia, A. Knetsch, C. Lechner, W. Leemans, B. Marchetti, A. Martinez de la Ossa, P. Niknejadi, J. Osterhoff, K. Poder, R. Rossmanith, L. Schaper, E.N. Svystun, G.E. Tauscher, P.A. Walker, J. Zhu DESY, Hamburg, Germany T. Akhter, S. De Nicola INFN-Napoli, Napoli, Italy D. Alesini, M.P. Anania, F.G. Bisesto, E. Chiadroni, M. Croia, A. Del Dotto, M. Ferrario, F. Filippi, A. Gallo, A. Giribono, R. Pompili, S. Romeo, J. Scifo, C. Vaccarezza, F. Villa INFN/LNF, Frascati, Italy A.S. Alexandrova, R. Torres, C.P. Welsch, J. Wolfenden The University of Liverpool, Liverpool, United Kingdom A.S. Alexandrova, A. Beaton, J.A. Clarke, A.F. Habib, T. Heinemann, B. Hidding, P. Scherkl, N. Thompson, R. Torres, D. Ullmann, C.P. Welsch, S.M. Wiggins, J. Wolfenden, G.X. Xia Cockcroft Institute, Warrington, Cheshire, United Kingdom N.E. Andreev, D. Pugacheva JIHT RAS, Moscow, Russia N.E. Andreev, D. Pugacheva MIPT, Dolgoprudniy, Moscow Region, Russia I.A. Andriyash, M.-E. Couprie, A. Ghaith, D. Oumbarek Espinos SOLEIL, Gif-sur-Yvette, France T. Audet, B. Cros, G. Maynard CNRS LPGP Univ Paris Sud, Orsay, France A. Bacci, D. Giove, V. Petrillo, A.R. Rossi, L. Serafini INFN-Milano, Milano, Italy I.F. Barna, M.A. Pocsai Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary A. Beaton, A.F. Habib, T. Heinemann, B. Hidding, D.A. Jaroszynski, G.G. Manahan, P. Scherkl, Z.M. Sheng, D. Ullmann, S.M. Wiggins USTRAT/SUPA, Glasgow, United Kingdom A. Beck, F. Massimo, A. Specka LLR, Palaiseau, France A. Beluze, F. Mathieu, D.N. Papadopoulos LULI, Palaiseau, France A. Bernhard, E. Bründermann, A.-S. Müller KIT, Karlsruhe, Germany S. Bielawski, E. Roussel, C. Szwaj PhLAM/CERLA, Villeneuve d’Ascq, France F. Brandi, G. Bussolino, L.A. Gizzi, P. Koester, L. Labate, B. Patrizi, G. Toci, P. Tomassini, M. Vannini INO-CNR, Pisa, Italy M.H. Bussmann, A. Irman, U. Schramm HZDR, Dresden, Germany M. Büscher, A. Lehrach FZJ, Jülich, Germany A. Chancé, P.A.P. Nghiem, C. Simon CEA-IRFU, Gif-sur-Yvette, France M. Chen, Z.M. Sheng Shanghai Jiao Tong University, Shanghai, People’s Republic of China A. Cianchi Università di Roma II Tor Vergata, Roma, Italy A. Cianchi INFN-Roma II, Roma, Italy J.A. Clarke, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J. Cole, S.M. Hooker, M.J.V. Streeter, R. Walczak JAI, London, United Kingdom P.A. Crump, M. Huebner FBH, Berlin, Germany G. Dattoli, F. Nguyen ENEA C.R. Frascati, Frascati (Roma), Italy N. Delerue, K. Wang LAL, Orsay, France J.M. Dias, R.A. Fonseca, J.L. Martins, L.O. Silva, T. Silva, U. Sinha, J.M. Vieira IPFN, Lisbon, Portugal R. Fedele, G. Fiore, D. Terzani UniNa, Napoli, Italy A. Ferran Pousa, T. Heinemann, V. Libov University of Hamburg, Hamburg, Germany M. Galimberti, P.D. Mason, R. Pattathil, D. Symes STFC/RAL, Chilton, Didcot, Oxon, United Kingdom L.A. Gizzi, L. Labate INFN-Pisa, Pisa, Italy F.J. Grüner, A.R. Maier CFEL, Hamburg, Germany F.J. Grüner, O.S. Karger, A.R. Maier University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany C. Haefner, C. Siders LLNL, Livermore, California, USA B.J. Holzer CERN, Geneva, Switzerland S.M. Hooker University of Oxford, Oxford, United Kingdom T. Hosokai ISIR, Osaka, Japan C. Joshi UCLA, Los Angeles, California, USA M. Kaluza IOQ, Jena, Germany M. Kaluza HIJ, Jena, Germany M. Kando JAEA/Kansai, Kyoto, Japan S. Karsch LMU, Garching, Germany E. Khazanov, I. Kostyukov IAP/RAS, Nizhny Novgorod, Russia D. Khikhlukha, D. Kocon, G. Korn, K.O. Kruchinin, A.Y. Molodozhentsev, L. Pribyl ELI-BEAMS, Prague, Czech Republic O.S. Kononenko, A. Lifschitz LOA, Palaiseau, France C. Le Blanc, Z. Mazzotta Ecole Polytechnique, Palaiseau, France X. Li DESY Zeuthen, Zeuthen, Germany V. Litvinenko BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA W. Lu TUB, Beijing, People’s Republic of China O. Lundh Lund University, Lund, Sweden V. Malka Weizmann Institute of Science, Physics, Rehovot, Israel S.P.D. Mangles, Z. Najmudin, A.A. Sahai Imperial College of Science and Technology, Department of Physics, London, United Kingdom A. Mostacci INFN-Roma, Roma, Italy A. Mostacci Sapienza University of Rome, Rome, Italy C.D. Murphy York University, Heslington, York, United Kingdom V. Petrillo Universita’ degli Studi di Milano, Milano, Italy M. Rossetti Conti Universita’ degli Studi di Milano & INFN, Milano, Italy G. Sarri Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom C.B. Schroeder LBNL, Berkeley, California, USA C.-G. Wahlstrom Lund Institute of Technology (LTH), Lund University, Lund, Sweden R. Walczak Oxford University, Physics Department, Oxford, Oxon, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom M. Yabashi RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan A. Zigler The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
	Funding: This work was supported by the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No. 653782. The Horizon 2020 Project EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) is producing a conceptual design report for a highly compact and cost-effective European facility with multi-GeV electron beams accelerated using plasmas. EuPRAXIA will be set up as a distributed Open Innovation platform with two construction sites, one with a focus on beam-driven plasma acceleration (PWFA) and another site with a focus on laser-driven plasma acceleration (LWFA). User areas at both sites will provide access to FEL pilot experiments, positron generation and acceleration, compact radiation sources, and test beams for HEP detector development. Support centres in four different countries will complement the pan-European implementation of this infrastructure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW026
About •	paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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THPGW048	Temporal Characterization of Electron Bunches From Self-Injection and Ionization Injection in a Laser Wakefield Accelerator	3693
	J. Zhang, Y.X. He, J.F. Hua, D.X. Liu, W. Lu, Y. Ma, C.H. Pai, Y.P. Wu TUB, Beijing, People’s Republic of China Z. Nie, Q. Su UCLA, Los Angeles, California, USA
	Plasma based accelerators (PBAs) have a proven capability to generate high energy electron beams with ultrashort duration (~ 10 fs) and high peak current (~ 10 kA), which opens the opportunity for compact free electron lasers. To meet the requirements of such challenging applications, controllable injection is highly needed to produce high-quality and highly stable electron beams. As we know, the beam parameters，including the current profile, strongly depend on the injection process. To explore the underlying physics and optimize beam parameters in PBAs, a temporal characterization is highly required for different injection schemes. Based on coherent transition radiation(CTR) method, the preliminary experiment to measure beam temporal profiles from both self-injection and ionization injection schemes in a single-shot mode has been performed at Tsinghua University. And the simulations using the similar experimental parameters have been performed to interpret the different injection processes, which show some agreement with the experimental results, especially for the features of bunch durations
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW048
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPGW050	Electromagnetic Field of a Charge Moving Through a Channel in Magnetized Plasma	3700
	A.A. Grigoreva, T.Yu. Alekhina, S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev Saint Petersburg State University, Saint Petersburg, Russia
	Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137). Recent success in beam-driven plasma wakefiled acceleration scheme with two proton bunches propagating through a hollow plasma channel* stimulates the research activity in this area. In this report, we investigate possibilities for additional tuning the structure of the accelerating field by the external magnetic field applied. The structure of surface waves at the channel boundary is of interest, and special attention is paid to the field characteristics that are essential for the wakefield acceleration method (amplitude of the accelerating field, the structure of the deflecting field) and the possibilities of controlling these characteristics by means of the external field. * Gessner S.J. et al. Proc. IPAC2016. THPPA01.
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THPGW059	Laser-Plasma Acceleration Modeling Approach in the Case of ESCULAP Project.	3723
	V. Kubytskyi, C. Bruni, K. Cassou, V. Chaumat, N. Delerue, D. Douillet, S. Jenzer, H. Purwar, K. Wang LAL, Orsay, France E. Baynar, M. Pittman CLUPS, Orsay, France J. Demailly, O. Guilbaud, S. Kazamias, B. Lucas, G. Maynard, O. Neveu, D. Ros CNRS LPGP Univ Paris Sud, Orsay, France D. Garzella CEA-IRFU, Gif-sur-Yvette, France R. Prazeres CLIO/ELISE/LCP, Orsay, France
	Objective of ESCULAP project is the experimental study of Laser-Plasma Acceleration (LPA) of relativistic electron bunch from photo-injector in 10 cm length plasma cell . In parallel, numerical tools have been developed in order to optimize the setup configuration and the analysis of the expected results. The most important issue when dealing with numerical simulation over such large interaction distances is to obtain a good accuracy at a limited computing cost in order to be able to perform parametric studies. Reduction of the computational cost can be obtained either by using state-of-the-art numerical technics and/or by introducing adapted approximation in the physical model. Concerning LPA, the relevant Maxwell-Vlasov equations can be numerically solved by Particle-In-Cell (PIC) methods without any additional approximation, but can be very computationally expensive. On the other hand, the quasi-static approximation , which yields a drastic reduction of the computational cost, appears to be well adapted to the LPA regime. In this paper we present a detailed comparison of the performance, in terms of CPU, of LPA calculations and of the accuracies of their results obtained either with a highly optimized PIC code (FBPIC ) or with the well known quasi-static code WAKE **. We first show that, when considering a sufficiently low charge bunch for which the beam loading effect can be neglected, the quasi-static approximation is fully validated in the LPA regime. The case of a higher bunch charge, with significant beam loading effects, has also been investigated using an enhanced version of WAKE, named WAKE-EP. Additionally, a cost evaluation, in terms of used energy per calculation, has also been done using the multi-CPU and multi-GPU versions of FBPIC. E. Baynard et al, Nucl. Instrum. Meth. Phys. Res. A 909, 46 (2018) R.Lehe et al., Comp. Phys. Com. 203, 66 (2016) * P. Mora & A, Jr Th. Antonsen, Phys. of Plasmas 4, 217 (1997)
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About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW067	Progress Towards a Single-Shot Emittance Measurement Technique at AWAKE	3742
SUSPFO113	use link to see paper's listing under its alternate paper code
	J. Chappell, D.A. Cooke, L.C. Deacon, S. Jolly, F. Keeble, M. Wing UCL, London, United Kingdom
	Externally injected electrons are captured and accelerated in the plasma wake of a self-modulated proton beam at the Advanced Wakefield Experiment (AWAKE) at CERN. The energy distribution of the accelerated electron beam is measured using a dipole spectrometer in combination with a scintillator screen, with two upstream quadrupoles providing energy-dependent focusing. Measuring the vertical beam size variation with horizontal position along the scintillator screen, and therefore energy, results in an effective quadrupole scan permitting single shot vertical geometric emittance measurements. Limitations of the method due to effects such as imperfect beam focusing and finite resolution are explored via simulations using the beam tracking code BDSIM. james.chappell.17@ucl.ac.uk
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About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW070	Design of the Cockcroft Beamline: Adjustable Transport of Laser Wakefield Electrons to an Undulator	3749
SUSPFO114	use link to see paper's listing under its alternate paper code
	K.A. Dewhurst, H.L. Owen UMAN, Manchester, United Kingdom E. Brunetti, D.A. Jaroszynski, S.M. Wiggins USTRAT/SUPA, Glasgow, United Kingdom B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.J. de Loos, S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: Work supported by U.K. STFC (Grant No. ST/G008248/1), EuPRAXIA (Grant No. 653782), ECs LASERLAB-EUROPE (Grant No. 654148), U.K. EPSRC (Grant No. EP/J018171/1, EP/J500094/1 and EP/N028694/1). The Cockcroft Beamline is being designed to transport 1 GeV electrons from a laser wakefield accelerator (LWFA) to an undulator at the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) in Glasgow, UK. To demonstrate undulator radiation in the X-ray spectral region and potentially free electron laser (FEL) gain, electrons should be transported between the LWFA and the undulators with high fidelity. In this paper we present the design of an adjustable beam line to transport LWFA electrons to the undulator for a range of energies, from 0.5 GeV to 1 GeV, while preserving the electron beam properties and matching the undulator-beam coupling.
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THPGW072	Seeded Self-Modulation of Transversely Asymmetric Long Proton Beams in Plasma	3757
	T.A. Perera, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom P. Muggli MPI-P, München, Germany T.A. Perera, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work is supported by Science and Technology Facilities Council grant ST/P006752/1. The AWAKE experiment at CERN recently demonstrated the world’s first acceleration of electrons in a proton-driven plasma wakefield accelerator. Such accelerators show great promise for a new generation of linear e-p colliders using ~1-10 GV/m accelerating fields. Effectively driving a wakefield requires 100-fold self-modulation of the 12 cm Super Proton Synchrotron (SPS) proton beam using a plasma-driven process which must be care-fully controlled to saturation. Previous works have modelled this process assuming azimuthal symmetry of the transverse spatial and momentum profiles , *. In this work, 3D particle-in-cell simulations are used to model the self-modulation of such non-round beams. Implications of such effects for efficiently sustaining resonant wakefields are examined. Adli, E., et. al. (2018). Nature, 561(7723), 363-367. Lotov, K. V. (2015). Physics of Plasmas, 22(10), 103110. * Schroeder, C. B., et. al. (2011). Phys. Rev. Lett., 107(14).
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THPGW087	Transverse Jitter Tolerance Issues for Beam-Driven Plasma Accelerators	3774
	G.R. White, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: Work supported by the Department of Energy under Contract Number: DE-AC02-76SF00515. Transverse jitter tolerances are considered for beam-driven plasma accelerators. A simple model for jitter transfer from the drive to witness beam is developed and concrete examples are studied for: high-brightness witness bunch injectors; high-energy boosters for FEL’s; and future Linear Colliders. Compared with an existing PWFA driver facility ([,]), the calculated tolerances are 18X ’ 170X tighter than achievable, even considering any upgrades with existing technology. Nature 445 741 Feb 2007, Nature 515, Nov. 2014 ** FACET-II Technical Design Report, SLAC-R-1072, "The FLASHForward facility at DESY", NIMA Oct., 2015
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Paper

Title

Page

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

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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WEZZPLS1

Experimental Demonstration of External Injection From a Linac into a LWFA with ~100% Capture Efficiency

J.F. Hua, Y.C. Du, Y. Fang, S. Liu, W. Lu, C.H. Pai, B. Peng, Y.P. Wu, J. Zhang, Z. Zhou
TUB, Beijing, People’s Republic of China

Staging of conventional accelerators and advanced plasma-based accelerators can boost the beam energy while at the same time better control the beam quality, therefore it is essential for high-energy applications such as TeV-level colliders. Here we present the first successful demonstration of external injection from a linear accelerator (LINAC) into a laser wakefield accelerator (LWFA) and the subsequent acceleration with ~100% capture efficiency. Stable 31MeV, 20fC electron beams from the LINAC were velocity bunched to the length of ~15fs (r.m.s.) in the high-gradient photocathode RF gun and then external injected into the linear wakefield excited by the 10TW, 42fs laser. The experimental results show that nearly all the electrons can be mono-energetically accelerated and the maximum energy gain reaches 1.8MeV in a 6-mm long plasma, corresponding to an average gradient of about 300MV/m. High capture efficiency of external injection has also been systematically validated by 3D PIC simulations. This paves the way toward the development of high-energy particle accelerators for future colliders.

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WEZZPLS2

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

2291

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

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

Slides WEZZPLS2 [5.157 MB]

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THPGW002

A Passive Plasma Beam Dump Study with Application to EuPRAXIA

3581

R.P. Nunes
UFRGS, Porto Alegre, Brazil
A. Bonatto
University of Manchester, Manchester, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: The author R. P. Nunes acknowledges the financial support provided by FAPERGS.
This work presents a study about a passive dumping scheme applied to the beam generated by the accelerator stage of the EuPraxia experiment. Particle-in-cell simulations have been carried out and its results are compared with analytical estimates, showing a reasonable agreement.

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THPGW003

Energy Loss of an Electron Beam with Gaussian Density Profile Propagating in a Passive Plasma Beam Dump

3584

A. Bonatto
University of Manchester, Manchester, United Kingdom
R.P. Nunes
UFRGS, Porto Alegre, Brazil
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: CNPq, and FAPERGS, from Brazil.
A semi-analytical 1D model is derived for the total energy loss of an electron beam with Gaussian density profile undergoing a passive plasma beam dump. The model is compared to a previous one, obtained for a half-sine longitudinal density profile. It is shown that both models agree if the beam density profiles are properly matched, and if their sizes are small in comparison to the length of wakefield decelerating length. The beam energy obtained from both models is compared to 1D PIC simulation results.

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

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THPGW006

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

3594

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

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

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THPGW012

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

3601

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

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

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paper received ※ 24 April 2019 paper accepted ※ 21 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

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

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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THPGW017

Self-Modulation Instability of Electron Beams in Plasma Channels of Variable Length

3616

O. Lishilin, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, G. Loisch, 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 self-modulation instability (SMI) of long (in respect to the plasma wavelength) charged particle beams passing through plasma enables the use of currently existing high energy charged particle beams as drivers for plasma wakefield accelerators. At the Photo Injector Test facility at DESY in Zeuthen (PITZ) the SMI of electron beams is studied *, **. An enhanced experimental setup includes a plasma channel of variable length which allows to investigate in details the development stages of the SMI by measuring the instability growth rate and phase velocity as a function of propagation distance in the plasma. In this contribution we present the experimental setup improvements, first measurement results and supporting beam dynamics simulations.
* M. Gross, et al., Phys. Rev. Lett., vol. 120, p. 144802, 2018.
** G. Loisch, et al., Plasma Physics and Controlled Fusion, vol. 61(4), p. 045012, 2019

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paper received ※ 11 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPGW019

FLASHforward Findings for the EuPRAXIA Design Study and the Next-Generation of Compact Accelerator Facilities

3619

P. Niknejadi, R.T.P. D’Arcy, J.M. Garland, J. Osterhoff, L. Schaper, B. Schmidt, G.E. Tauscher
DESY, Hamburg, Germany
M. Ferrario, S. Romeo
INFN/LNF, Frascati, Italy
C.A. Lindstrøm
University of Oslo, Oslo, Norway
T.J. Mehrling
LBNL, Berkeley, USA

FLASHForward, the exploratory FLASH beamline for Future-ORiented Wakefield Accelerator Research and Development, is a European pilot test bed facility for accelerating electron beams to GeV-levels in a few centimeters of ionized gas. The main focus is on the advancement of plasma-based particle acceleration technology through investigation of injection schemes, novel concepts and diagnostics, as well as benchmarking theoretical studies and simulations. Since the plasma wakefield will be driven by the optimal high-current-density electron beams extracted from the FLASH L-band Superconducting RF accelerator, FLASHForward has been in a unique position for studying and providing insight for the design study of next-generation light source and high energy physics facilities such as EuPRAXIA*. Summary of these findings and their broader impact is discussed here.
*P. A. Walker, et. al., "Horizon 2020 EuPRAXIA design study," Journal of Physics Conference Series 874(1):012029, July 2017.

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paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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THPGW022

The Effect of the Transverse Beam Jitter on the Accelerated Electron Beam Quality in a Laser-Driven Plasma Accelerator with External Injection at SINBAD for ATHENAe

3624

E.N. Svystun, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

Laser plasma accelerators with external injection of an RF-generated electron beam, providing high accelerating field gradients and increased control over the electron beam injection process, are promising candidates for production electron beams matching the requirements of modern user-applications. The experiments are planned at the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility to test this acceleration technique in the context of the ATHENAe (Accelerator Technology HElmholtz iNfrAstructure) project. In this paper we present numerical studies on the effect of the transverse electron beam jitter on the final quality of a sub-femtosecond, 0.75 pC, 100 MeV electron beam accelerated to 1 GeV energy in the plasma wakefield driven by a 196 TW, 5 J laser pulse.

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

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THPGW023

Numerical Studies on Electron Beam Quality Optimization in a Laser-Driven Plasma Accelerator with External Injection at SINBAD for ATHENAe

3628

E.N. Svystun, R.W. Aßmann, U. Dorda, B. Marchetti, A. Martinez de la Ossa
DESY, Hamburg, Germany

Nowadays the electron beams produced in plasma-based accelerators (PBAs) are of sufficient energy for multi-GeV applications. However, to allow PBAs to be usable for demanding applications such as Free-Electron Lasers, the quality and stability of plasma-accelerated beams have to be improved. We present numerical studies on accelera-tion of an RF-generated electron beam with a charge of 0.8 pC and initial mean energy of 100 MeV to GeV energies by a laser-plasma accelerator. This acceleration scheme is planned to be tested experimentally within the framework of the ATHENAe (Accelerator Technology HElmholtz iNfrAstructure) project at the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY, Hamburg. Electron beam injection, acceleration and extraction from the plasma are investigated through start-to-end 3D simulations. The effect of the injection phase on the accelerated beam quality is investigated through tolerance studies on the arrival-time jitter between the electron beam and the external laser.

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

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THPGW025

Facility Considerations for a European Plasma Accelerator Infrastructure (EuPRAXIA)

3635

P.A. Walker, R.W. Aßmann, U. Dorda, B. Marchetti, M.K. Weikum
DESY, Hamburg, Germany
E. Chiadroni, M. Ferrario
INFN/LNF, Frascati, Italy
A. Specka
LLR, Palaiseau, France
R. Walczak
JAI, Oxford, United Kingdom

Funding: This work was supported by the European Union‘s Horizon 2020 research and innovation programme under grant agreement No. 653782.
EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) is a conceptual design study for a compact European infrastructure with multi-GeV electron beams based on plasma accelerators. The concept foresees two main experimental sites, one at INFN in Frascati and one at DESY in Hamburg. In Frascati, an RF injector based on S-band and X-band technology (electron energy up to 1 GeV) will be constructed and used as a drive beam for beam driven plasma acceleration (PWFA) with final electron beam energies up to 5 GeV. At DESY, the focus will be on laser driven plasma acceleration (LWFA) and an RF injector based on S-band technology (electron energy up to 240 MeV) or alternatively a plasma injector (electron energy up to 150 MeV) can be used before the beam is injected into the plasma accelerator for external LWFA and acceleration up to 5 GeV. A single stage approach based on LWFA with internal injection will also be pursued in a second beamline. User areas at both sites will provide access to FEL pilot experiments, positron generation, compact radiation sources, and test beams for HEP detector development. This contribution discusses facility space considerations for the future plasma accelerator research infrastructure of EuPRAXIA.

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paper received ※ 13 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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THPGW026

Status of the Horizon 2020 EuPRAXIA Conceptual Design Study

3638

M.K. Weikum, A. Aschikhin, R.W. Aßmann, R. Brinkmann, U. Dorda, A. Ferran Pousa, T. Heinemann, F. Jafarinia, A. Knetsch, C. Lechner, W. Leemans, B. Marchetti, A. Martinez de la Ossa, P. Niknejadi, J. Osterhoff, K. Poder, R. Rossmanith, L. Schaper, E.N. Svystun, G.E. Tauscher, P.A. Walker, J. Zhu
DESY, Hamburg, Germany
T. Akhter, S. De Nicola
INFN-Napoli, Napoli, Italy
D. Alesini, M.P. Anania, F.G. Bisesto, E. Chiadroni, M. Croia, A. Del Dotto, M. Ferrario, F. Filippi, A. Gallo, A. Giribono, R. Pompili, S. Romeo, J. Scifo, C. Vaccarezza, F. Villa
INFN/LNF, Frascati, Italy
A.S. Alexandrova, R. Torres, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
A.S. Alexandrova, A. Beaton, J.A. Clarke, A.F. Habib, T. Heinemann, B. Hidding, P. Scherkl, N. Thompson, R. Torres, D. Ullmann, C.P. Welsch, S.M. Wiggins, J. Wolfenden, G.X. Xia
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N.E. Andreev, D. Pugacheva
JIHT RAS, Moscow, Russia
N.E. Andreev, D. Pugacheva
MIPT, Dolgoprudniy, Moscow Region, Russia
I.A. Andriyash, M.-E. Couprie, A. Ghaith, D. Oumbarek Espinos
SOLEIL, Gif-sur-Yvette, France
T. Audet, B. Cros, G. Maynard
CNRS LPGP Univ Paris Sud, Orsay, France
A. Bacci, D. Giove, V. Petrillo, A.R. Rossi, L. Serafini
INFN-Milano, Milano, Italy
I.F. Barna, M.A. Pocsai
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
A. Beaton, A.F. Habib, T. Heinemann, B. Hidding, D.A. Jaroszynski, G.G. Manahan, P. Scherkl, Z.M. Sheng, D. Ullmann, S.M. Wiggins
USTRAT/SUPA, Glasgow, United Kingdom
A. Beck, F. Massimo, A. Specka
LLR, Palaiseau, France
A. Beluze, F. Mathieu, D.N. Papadopoulos
LULI, Palaiseau, France
A. Bernhard, E. Bründermann, A.-S. Müller
KIT, Karlsruhe, Germany
S. Bielawski, E. Roussel, C. Szwaj
PhLAM/CERLA, Villeneuve d’Ascq, France
F. Brandi, G. Bussolino, L.A. Gizzi, P. Koester, L. Labate, B. Patrizi, G. Toci, P. Tomassini, M. Vannini
INO-CNR, Pisa, Italy
M.H. Bussmann, A. Irman, U. Schramm
HZDR, Dresden, Germany
M. Büscher, A. Lehrach
FZJ, Jülich, Germany
A. Chancé, P.A.P. Nghiem, C. Simon
CEA-IRFU, Gif-sur-Yvette, France
M. Chen, Z.M. Sheng
Shanghai Jiao Tong University, Shanghai, People’s Republic of China
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Cianchi
INFN-Roma II, Roma, Italy
J.A. Clarke, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J. Cole, S.M. Hooker, M.J.V. Streeter, R. Walczak
JAI, London, United Kingdom
P.A. Crump, M. Huebner
FBH, Berlin, Germany
G. Dattoli, F. Nguyen
ENEA C.R. Frascati, Frascati (Roma), Italy
N. Delerue, K. Wang
LAL, Orsay, France
J.M. Dias, R.A. Fonseca, J.L. Martins, L.O. Silva, T. Silva, U. Sinha, J.M. Vieira
IPFN, Lisbon, Portugal
R. Fedele, G. Fiore, D. Terzani
UniNa, Napoli, Italy
A. Ferran Pousa, T. Heinemann, V. Libov
University of Hamburg, Hamburg, Germany
M. Galimberti, P.D. Mason, R. Pattathil, D. Symes
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
L.A. Gizzi, L. Labate
INFN-Pisa, Pisa, Italy
F.J. Grüner, A.R. Maier
CFEL, Hamburg, Germany
F.J. Grüner, O.S. Karger, A.R. Maier
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
C. Haefner, C. Siders
LLNL, Livermore, California, USA
B.J. Holzer
CERN, Geneva, Switzerland
S.M. Hooker
University of Oxford, Oxford, United Kingdom
T. Hosokai
ISIR, Osaka, Japan
C. Joshi
UCLA, Los Angeles, California, USA
M. Kaluza
IOQ, Jena, Germany
M. Kaluza
HIJ, Jena, Germany
M. Kando
JAEA/Kansai, Kyoto, Japan
S. Karsch
LMU, Garching, Germany
E. Khazanov, I. Kostyukov
IAP/RAS, Nizhny Novgorod, Russia
D. Khikhlukha, D. Kocon, G. Korn, K.O. Kruchinin, A.Y. Molodozhentsev, L. Pribyl
ELI-BEAMS, Prague, Czech Republic
O.S. Kononenko, A. Lifschitz
LOA, Palaiseau, France
C. Le Blanc, Z. Mazzotta
Ecole Polytechnique, Palaiseau, France
X. Li
DESY Zeuthen, Zeuthen, Germany
V. Litvinenko
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
W. Lu
TUB, Beijing, People’s Republic of China
O. Lundh
Lund University, Lund, Sweden
V. Malka
Weizmann Institute of Science, Physics, Rehovot, Israel
S.P.D. Mangles, Z. Najmudin, A.A. Sahai
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
A. Mostacci
INFN-Roma, Roma, Italy
A. Mostacci
Sapienza University of Rome, Rome, Italy
C.D. Murphy
York University, Heslington, York, United Kingdom
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy
M. Rossetti Conti
Universita’ degli Studi di Milano & INFN, Milano, Italy
G. Sarri
Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom
C.B. Schroeder
LBNL, Berkeley, California, USA
C.-G. Wahlstrom
Lund Institute of Technology (LTH), Lund University, Lund, Sweden
R. Walczak
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom
M. Yabashi
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

Funding: This work was supported by the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No. 653782.
The Horizon 2020 Project EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) is producing a conceptual design report for a highly compact and cost-effective European facility with multi-GeV electron beams accelerated using plasmas. EuPRAXIA will be set up as a distributed Open Innovation platform with two construction sites, one with a focus on beam-driven plasma acceleration (PWFA) and another site with a focus on laser-driven plasma acceleration (LWFA). User areas at both sites will provide access to FEL pilot experiments, positron generation and acceleration, compact radiation sources, and test beams for HEP detector development. Support centres in four different countries will complement the pan-European implementation of this infrastructure.

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paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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THPGW048

Temporal Characterization of Electron Bunches From Self-Injection and Ionization Injection in a Laser Wakefield Accelerator

3693

J. Zhang, Y.X. He, J.F. Hua, D.X. Liu, W. Lu, Y. Ma, C.H. Pai, Y.P. Wu
TUB, Beijing, People’s Republic of China
Z. Nie, Q. Su
UCLA, Los Angeles, California, USA

Plasma based accelerators (PBAs) have a proven capability to generate high energy electron beams with ultrashort duration (~ 10 fs) and high peak current (~ 10 kA), which opens the opportunity for compact free electron lasers. To meet the requirements of such challenging applications, controllable injection is highly needed to produce high-quality and highly stable electron beams. As we know, the beam parameters，including the current profile, strongly depend on the injection process. To explore the underlying physics and optimize beam parameters in PBAs, a temporal characterization is highly required for different injection schemes. Based on coherent transition radiation(CTR) method, the preliminary experiment to measure beam temporal profiles from both self-injection and ionization injection schemes in a single-shot mode has been performed at Tsinghua University. And the simulations using the similar experimental parameters have been performed to interpret the different injection processes, which show some agreement with the experimental results, especially for the features of bunch durations

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

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THPGW050

Electromagnetic Field of a Charge Moving Through a Channel in Magnetized Plasma

3700

A.A. Grigoreva, T.Yu. Alekhina, S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia

Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
Recent success in beam-driven plasma wakefiled acceleration scheme with two proton bunches propagating through a hollow plasma channel* stimulates the research activity in this area. In this report, we investigate possibilities for additional tuning the structure of the accelerating field by the external magnetic field applied. The structure of surface waves at the channel boundary is of interest, and special attention is paid to the field characteristics that are essential for the wakefield acceleration method (amplitude of the accelerating field, the structure of the deflecting field) and the possibilities of controlling these characteristics by means of the external field.
* Gessner S.J. et al. Proc. IPAC2016. THPPA01.

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

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THPGW059

Laser-Plasma Acceleration Modeling Approach in the Case of ESCULAP Project.

3723

V. Kubytskyi, C. Bruni, K. Cassou, V. Chaumat, N. Delerue, D. Douillet, S. Jenzer, H. Purwar, K. Wang
LAL, Orsay, France
E. Baynar, M. Pittman
CLUPS, Orsay, France
J. Demailly, O. Guilbaud, S. Kazamias, B. Lucas, G. Maynard, O. Neveu, D. Ros
CNRS LPGP Univ Paris Sud, Orsay, France
D. Garzella
CEA-IRFU, Gif-sur-Yvette, France
R. Prazeres
CLIO/ELISE/LCP, Orsay, France

Objective of ESCULAP project is the experimental study of Laser-Plasma Acceleration (LPA) of relativistic electron bunch from photo-injector in 10 cm length plasma cell *. In parallel, numerical tools have been developed in order to optimize the setup configuration and the analysis of the expected results. The most important issue when dealing with numerical simulation over such large interaction distances is to obtain a good accuracy at a limited computing cost in order to be able to perform parametric studies. Reduction of the computational cost can be obtained either by using state-of-the-art numerical technics and/or by introducing adapted approximation in the physical model. Concerning LPA, the relevant Maxwell-Vlasov equations can be numerically solved by Particle-In-Cell (PIC) methods without any additional approximation, but can be very computationally expensive. On the other hand, the quasi-static approximation ***, which yields a drastic reduction of the computational cost, appears to be well adapted to the LPA regime. In this paper we present a detailed comparison of the performance, in terms of CPU, of LPA calculations and of the accuracies of their results obtained either with a highly optimized PIC code (FBPIC **) or with the well known quasi-static code WAKE ***. We first show that, when considering a sufficiently low charge bunch for which the beam loading effect can be neglected, the quasi-static approximation is fully validated in the LPA regime. The case of a higher bunch charge, with significant beam loading effects, has also been investigated using an enhanced version of WAKE, named WAKE-EP. Additionally, a cost evaluation, in terms of used energy per calculation, has also been done using the multi-CPU and multi-GPU versions of FBPIC.
* E. Baynard et al, Nucl. Instrum. Meth. Phys. Res. A 909, 46 (2018)
** R.Lehe et al., Comp. Phys. Com. 203, 66 (2016)
*** P. Mora & A, Jr Th. Antonsen, Phys. of Plasmas 4, 217 (1997)

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

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THPGW067

Progress Towards a Single-Shot Emittance Measurement Technique at AWAKE

3742

SUSPFO113

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

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

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

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THPGW070

Design of the Cockcroft Beamline: Adjustable Transport of Laser Wakefield Electrons to an Undulator

3749

SUSPFO114

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K.A. Dewhurst, H.L. Owen
UMAN, Manchester, United Kingdom
E. Brunetti, D.A. Jaroszynski, S.M. Wiggins
USTRAT/SUPA, Glasgow, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.J. de Loos, S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: Work supported by U.K. STFC (Grant No. ST/G008248/1), EuPRAXIA (Grant No. 653782), ECs LASERLAB-EUROPE (Grant No. 654148), U.K. EPSRC (Grant No. EP/J018171/1, EP/J500094/1 and EP/N028694/1).
The Cockcroft Beamline is being designed to transport 1 GeV electrons from a laser wakefield accelerator (LWFA) to an undulator at the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) in Glasgow, UK. To demonstrate undulator radiation in the X-ray spectral region and potentially free electron laser (FEL) gain, electrons should be transported between the LWFA and the undulators with high fidelity. In this paper we present the design of an adjustable beam line to transport LWFA electrons to the undulator for a range of energies, from 0.5 GeV to 1 GeV, while preserving the electron beam properties and matching the undulator-beam coupling.

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THPGW072

Seeded Self-Modulation of Transversely Asymmetric Long Proton Beams in Plasma

3757

T.A. Perera, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
P. Muggli
MPI-P, München, Germany
T.A. Perera, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is supported by Science and Technology Facilities Council grant ST/P006752/1.
The AWAKE experiment at CERN recently demonstrated the world’s first acceleration of electrons in a proton-driven plasma wakefield accelerator*. Such accelerators show great promise for a new generation of linear e-p colliders using ~1-10 GV/m accelerating fields. Effectively driving a wakefield requires 100-fold self-modulation of the 12 cm Super Proton Synchrotron (SPS) proton beam using a plasma-driven process which must be care-fully controlled to saturation. Previous works have modelled this process assuming azimuthal symmetry of the transverse spatial and momentum profiles **, ***. In this work, 3D particle-in-cell simulations are used to model the self-modulation of such non-round beams. Implications of such effects for efficiently sustaining resonant wakefields are examined.
* Adli, E., et. al. (2018). Nature, 561(7723), 363-367.
** Lotov, K. V. (2015). Physics of Plasmas, 22(10), 103110.
*** Schroeder, C. B., et. al. (2011). Phys. Rev. Lett., 107(14).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW072

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

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THPGW087

Transverse Jitter Tolerance Issues for Beam-Driven Plasma Accelerators

3774

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

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

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW087

About •

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

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)