IPAC2017 - List of Keywords (plasma)

Paper	Title	Other Keywords	Page
MOZB1	First Results with the Novel Peta-Watt Laser Acceleration Facility in Dresden	laser, target, electron, acceleration	48
	U. Schramm, D. Albach, C. Bernert, S. Bock, F. Brack, J. Branco, M.H. Bussmann, J.P. Couperus, A.D. Debus, C. Eisenmann, M. Garten, R. Gebhardt, S. Grams, U. Helbig, A. Huebl, A. Irman, A. Köhler, J.M. Krämer, S. Kraft, F. Kroll, J. Metzkes, L. Obst, R.G. Pausch, M. Rehwald, H.P. Schlenvoigt, M. Siebold, K. Steiniger, O. Zarini, K. Zeil Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T. Kluge, M. Kuntzsch, U. Lehnert, M. Löser, P. Michel, R. Sauerbrey HZDR, Dresden, Germany
	Applications of laser plasma accelerated particle beams ranging from driving of light sources to radiation therapy require the scaling of beam energy and charge as well as reproducible operating conditions. Both issues have motivated the development of novel table-top class Petawatt laser systems (e.g., 30J pulse energy in 30fs) with unprecedented pulse control, here represented by the Draco-PW system recently commissioned at HZDR Dresden. First results will be presented on laser wakefield electron acceleration where in the beam loading regime high bunch charges in the nC range could be efficiently accelerated with good beam quality, and on proton acceleration where pulsed magnet beam transport ensured depth dose distributions allowing for tumor irradiation in animal models.
	Slides MOZB1 [4.059 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOZB1
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MOPAB039	Development of a Control System Based on Experimental Data for Space Charge Lenses	electron, operation, ion, space-charge	166
	S. Klaproth, C. Beberweil, M. Droba, O. Meusel, H. Podlech, B.E.J. Scheible, K. Schulte, K.I. Thoma, C. Wagner IAP, Frankfurt am Main, Germany
	Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past ,. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained. O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006
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MOPAB049	Development of a Focusing System for the AXSIS Project	linac, solenoid, quadrupole, focusing	203
	T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	In this paper, we investigate with ASTRA simulations the achievable performances for several focusing systems considered in the AXSIS project. We focus our attention on the requirements in terms of position of the focal point and bunch transverse size at this point. We show that they cannot be fulfilled with a solenoid resistive electro-magnet, but that it is possible when using a solenoid permanent magnet. The use of a quadrupole doublet proves to be adequate to fulfil the requirement on the position of the focal point and be very close to the one on the bunch transverse size, which could possibly be achieved by a further optimization of the parameters of the doublet. Finally, we also investigate the possibility to use an active plasma lens, showing that it could easily fulfil the requirements but that several points must be carefully studied before considering its implementation.
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MOPAB119	Beam Instrumentation Developments for the Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN	proton, electron, laser, electronics	404
	S. Mazzoni, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, S. Burger, F.S. Domingues Sousa, E. Effinger, J. Emery, A. Goldblatt, I. Gorgisyan, E. Gschwendtner, A. Guerrero, L.K. Jensen, T. Lefèvre, D. Medina, B. Moser, G. Schneider, L. Søby, M. Turner, M. Vicente Romero, M. Wendt CERN, Geneva, Switzerland B. Biskup Czech Technical University, Prague 6, Czech Republic M. Turner TUG/ITP, Graz, Austria V.A. Verzilov TRIUMF, Vancouver, Canada
	The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN aims to develop a proof-of-principle electron accelerator based on proton driven plasma wake-field acceleration. The core of AWAKE is a 10 metre long plasma cell filled with Rubidium vapour in which single, 400 GeV, proton bunches extracted from the CERN Super Proton Synchrotron (SPS) generate a strong plasma wakefield. The plasma is seeded using a femtosecond pulsed Ti:Sapphire laser. The aim of the experiment is to inject low energy electrons onto the plasma wake and accelerate them over this short distance to an energy of several GeV. To achieve its commissioning goals, AWAKE requires the precise measurement of the position and transverse profile of the laser, proton and electron beams as well as their temporal synchronisation. This contribution will present the beam instrumentation systems designed for AWAKE and their performance during the 2016 proton beam commissioning period.
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MOPAB153	R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments	cavity, electron, ion, experiment	491
	K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska Fermilab, Batavia, Illinois, USA R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA Q. Liu Case Western Reserve University, Cleveland, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764. A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.
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MOPIK016	Sub-Picosecond Beam Production for External Injection Into Plasma Experiments	gun, electron, linac, simulation	531
	O. Mete Apsimon, R. Apsimon, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: This work has been funded by STFC. Applications of plasmas in accelerators benefit from short probe bunches comparable to plasma wavelength due to currently achievable plasma wake profiles. In plasma acceleration case, high capture efficiency within a narrow energy spectrum can be achieved when a sub-picosecond to femtosecond witness bunch injected behind the driver pulse at the high electric field region. A start-to-end simulation study was performed for parametric optimisation of an rf photoinjector to provide a short witness bunch for plasma applications in accelerators. An rf photoinjector is a laser-driven, high brightness and robust electron source that can provide stability and flexibility provided by today's advanced laser and rf technologies.
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MOPIK032	Commissioning of the AISHa Ion Source at INFN-LNS	ion, ion-source, injection, operation	570
	L. Celona, G. Castro, F. Chines, G. Costa, S. Gammino, O. Leonardi, S. Marletta, D. Mascali, A. Maugeri, L. Neri, F. Noto, S. Passarello, G. Pastore, A. Seminara, G. Torrisi, S. Vinciguerra INFN/LNS, Catania, Italy S. Di Martino, P. Nicotra Si.A.Tel SRL, Catania, Italy
	At INFN-LNS the commissioning of the AISHa superconducting ECRIS started in November 2016. Highly charged ion beams with low ripple, high stability and high reproducibility are the most important features for the ongoing commissioning. In this work, we will show the preliminary results of a parametric study on the extracted current/beam in order to minimize the emittance and increase the brightness taking advantage by its hybrid magnetic system and by a fine frequency tuning system.
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MOPIK052	Generation of Highly-Charged Carbon Ions from Thin Foil Target	target, ion, laser, heavy-ion	635
	T. Kanesue, S. Ikeda, M. Okamura BNL, Upton, Long Island, New York, USA Y. Saito Sokendai, Ibaraki, Japan
	Funding: This work was supported by the U.S. Department of Energy and National Aeronautics and Space Administration. Generation of highly-charged heavy ions such as fully stripped C⁶⁺ of more than hundreds mA of beam current can be possible only with a laser ablation ion source (LIS). Heavy ions are produced from a solid target irradiated by a pulsed high power laser. Recent study showed that only sub-micron range of surface layer contributes for the generation of highly-charged heavy ions. In this paper, we experimentally investigated the difference of the performance of highly-charged carbon ion production from graphite targets of different thickness (25, 70, 254, and 3000 'm) to seek the possibility of a rolled target to overcome the limitation of a target lifetime.
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MOPIK053	Design Study of High Repetition Rate Laser Ion Source for High Power Beam Production	target, laser, ion, heavy-ion	638
	T. Kanesue, S. Ikeda, M. Okamura BNL, Upton, Long Island, New York, USA Y. Saito Sokendai, Ibaraki, Japan
	Funding: This work was supported by the U.S. Department of Energy and National Aeronautics and Space Administration. We are studying a laser ion source (LIS) for a high average beam power heavy ion beam production. A LIS is the most intense source of pulsed highly-charged ions using a laser ablation scheme. By increasing the repetition rate, a LIS based heavy ion beam would approach the average beam power based on a low beam current and continuous beam regime. In addition, a high-repetition-rate LIS can be used as a heavy ion source for a medical accelerator with spot scanning technique. This paper will describe the requirements to realize the high repetition rate operation.
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MOPVA082	PLASMA PROCESSING R&D OF THE 1.3 GHZ SINGLE-CELL SRF CAVITY AT IMP	cavity, SRF, accelerating-gradient, electromagnetic-fields	1055
	L. Yang, L. Chen, Y. He, S.C. Huang, C.X. Li, C.L. Li, Y.M. Li, L. Lu, A. Shi, L.P. Sun, A.D. Wu, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	The China-Accelerator Driven Sub-critical System (C-ADS) injector II has already commissioned with a CW 1 mA and a pulsed 10 mA proton beam. The beam energy achieved 10 MeV. The superconducting linac (SCL) is routinely operating at 4.7 MV/m average accelerating gradient in the low-beta cryomodules. Field emission and surface contaminants of the SCL limit the gradient in-crease in the beam commissioning. Hence, in order to increase the SCL accelerating gradient, reduce field emis-sion and remove surface pollutants, in-situ plasma pro-cessing R&D in a 1.3 GHz single-cell SRF cavity has being studied. In this paper, the current effort of plasma processing R&D in a 1.3 GHz single-cell SRF cavity will be presented in details and the future plan will be also reported.
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MOPVA100	Atomic Layer Deposition of Niobium Nitride from Different Precursors	niobium, experiment, controls, simulation	1094
	P. Pizzol, P. Chalker, J.W. Roberts, J. Wrench The University of Liverpool, Liverpool, United Kingdom O.B. Malyshev, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Advancements in technology have taken bulk niobium cavities close to their theoretical operational limits of 45 MV/m, pushing the research to explore novel materials, such as niobium based alloys . Theoretical studies suggest that a composite material composed of alternative superconductor / insulator multilayers would surpass the bulk niobium limits. Chemical vapour deposition (CVD) can deposit mi-crons thick Nb films in less than an hour, at the expense of precise thickness control. Atomic layer deposition (ALD), instead, even if considerably slower than CVD can be used in applications where the thickness of the deposited layers needs to be controlled with a resolution down to the nanometer. This article presents the preliminary results obtained by using plasma assisted ALD techniques to deposit NbN based compounds starting from chlorinated precursors and organic ones, and the design for a new deposition system currently being built at the Daresbury Laboratories.
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TUYB1	First Measurements of Trojan Horse Injection in a Plasma Wakefield Accelerator	laser, electron, wakefield, injection	1252
	B. Hidding, A. Beaton, A.F. Habib, T. Heinemann, G.G. Manahan, P. Scherkl, A. Sutherland, D. Ullmann USTRAT/SUPA, Glasgow, United Kingdom E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway E. Adli, S.J. Gessner CERN, Geneva, Switzerland G. Andonian, A. Deng, J.B. Rosenzweig UCLA, Los Angeles, California, USA G. Andonian RadiaBeam, Santa Monica, California, USA A. Beaton, A.F. Habib, T. Heinemann, B. Hidding, G.G. Manahan, P. Scherkl, A. Sutherland, D. Ullmann Cockcroft Institute, Warrington, Cheshire, United Kingdom D.L. Bruhwiler RadiaSoft LLC, Boulder, Colorado, USA J.R. Cary Tech-X, Boulder, Colorado, USA C.I. Clarke, S.Z. Green, M.J. Hogan, B.D. O'Shea, V. Yakimenko SLAC, Menlo Park, California, USA M. Downer, R. Zgadzaj The University of Texas at Austin, Austin, Texas, USA T. Heinemann, A. Knetsch DESY, Hamburg, Germany T. Heinemann, G. Wittig University of Hamburg, Hamburg, Germany O.S. Karger University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany M.D. Litos Colorado University at Boulder, Boulder, Colorado, USA J.D.A. Smith TXUK, Warrington, United Kingdom
	Funding: Work supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515. Plasma accelerators support accelerating fields of 100's of GV/m over meter-scale distances and routinely produce femtosecond-scale, multi-kA electron bunches. The so called Trojan Horse underdense photocathode plasma wakefield acceleration scheme combines state-of-the-art accelerator technology with laser and plasma methods and paves the way to improve beam quality as regards emittance and energy spread by many orders of magnitude. Electron beam brightness levels exceeding 10²⁰ Am^-2 rad^-2 may be reached, and the tunability allows for multi-GeV energies, designer bunches and energy spreads <0.05% in a single plasma accelerator stage. The talk will present results of the international E210 multi-year experimental program at SLAC FACET, which culminated in successful first demonstration of the Trojan Horse method during FACET's final experimental run in 2016. Enabling implications for applications, including high performance plasma-based 5th generation light sources such as hard x-ray FEL's, for which start-to-end simulations are presented, and for high energy physics are discussed.
	Slides TUYB1 [19.089 MB]
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TUOBB1	Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper	electron, laser, experiment, linac	1258
	Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou TUB, Beijing, People's Republic of China
	The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators. [] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports
	Slides TUOBB1 [10.555 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOBB1
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TUOBB2	Starting Up the AWAKE Experiment at CERN	proton, laser, electron, experiment	1261
	E. Gschwendtner CERN, Geneva, Switzerland
	AWAKE, the Advanced Proton Driven Plasma Wake-field Acceleration Experiment at CERN was approved in 2013. The facility was commissioned in 2016 to perform first experiments to demonstrate the self-modulation in-stability (SMI) of a 400 GeV/c SPS proton bunch in a 10 m long Rubidium plasma cell. The plasma is created in Rb vapor via field ionization by a TW laser pulse. In the second phase starting late 2017, the proton driven plasma wakefield will be probed with an externally injected 10 ' 20 MeV/c electron beam. This paper gives an overview of the AWAKE facility, describes the successful commissioning of the laser and proton beam line, the plasma cell and diagnostics and shows the successful synchronization of the proton beam with the laser at the few ps level so that the facility is ready for the SMI physics runs. In addition the status of the electron acceleration exper-iment for late 2017 will be presented.
	Slides TUOBB2 [3.513 MB]
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TUOBB3	HORIZON 2020 EuPRAXIA Design Study	laser, electron, acceleration, radiation	1265
	P.A. Walker, R.W. Aßmann, J. Bödewadt, R. Brinkmann, J. Dale, U. Dorda, A. Ferran Pousa, A.F. Habib, T. Heinemann, O. S. Kononenko, C. Lechner, B. Marchetti, A. Martinez de la Ossa, T.J. Mehrling, P. Niknejadi, J. Osterhoff, K. Poder, E.N. Svystun, G.E. Tauscher, M.K. Weikum, J. Zhu DESY, Hamburg, Germany D. Alesini, M.P. Anania, F.G. Bisesto, E. Chiadroni, M. Croia, M. Ferrario, F. Filippi, A. Gallo, A. Mostacci, R. Pompili, S. Romeo, J. Scifo, C. Vaccarezza, F. Villa INFN/LNF, Frascati (Roma), Italy A.S. Alexandrova, R.B. Fiorito, C.P. Welsch, J. Wolfenden The University of Liverpool, Liverpool, United Kingdom A.S. Alexandrova, R.B. Fiorito, C.P. Welsch, J. Wolfenden Cockcroft Institute, Warrington, Cheshire, United Kingdom N.E. Andreev, D. Pugacheva JIHT RAS, Moscow, Russia T. Audet, B. Cros, G. Maynard CNRS LPGP Univ Paris Sud, Orsay, France A. Bacci, D. Giove, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy I.F. Barna, M.A. Pocsai Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary A. Beaton, P. Delinikolas, B. Hidding, D.A. Jaroszynski, F.Y. Li, G.G. Manahan, P. Scherkl, Z.M. Sheng, M.K. Weikum USTRAT/SUPA, Glasgow, United Kingdom A. Beck, A. Specka LLR, Palaiseau, France A. Beluze, M. Mathieu, D.N. Papadopoulos LULI, Palaiseau, France A. Bernhard, E. Bründermann, A.-S. Müller KIT, Karlsruhe, Germany S. Bielawski PhLAM/CERLA, Villeneuve d'Ascq, France F. Brandi, G. Bussolino, L.A. Gizzi, P. Koester, B. Patrizi, G. Toci, M. Vannini INO-CNR, Pisa, Italy O. Bringer, A. Chancé, O. Delferrière, J. Fils, D. Garzella, P. Gastinel, X. Li, A. Mosnier, P.A.P. Nghiem, J. Schwindling, C. Simon CEA/IRFU, Gif-sur-Yvette, France M. Büscher, A. Lehrach FZJ, Jülich, Germany M. Chen, L. Yu Shanghai Jiao Tong University, Shanghai, People's Republic of China A. Cianchi Università di Roma II Tor Vergata, Roma, Italy J.A. Clarke, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.-E. Couprie SOLEIL, Gif-sur-Yvette, France G. Dattoli, F. Nguyen ENEA C.R. Frascati, Frascati (Roma), Italy N. Delerue LAL, Orsay, France J.M. Dias, R.A. Fonseca, J.L. Martins, L.O. Silva, U. Sinha, J. Vieira IPFN, Lisbon, Portugal K. Ertel, M. Galimberti, R. Pattathil, D. Symes STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J. Fils GSI, Darmstadt, Germany A. Giribono INFN-Roma, Roma, Italy L.A. Gizzi INFN-Pisa, Pisa, Italy F.J. Grüner, A.R. Maier CFEL, Hamburg, Germany F.J. Grüner, T. Heinemann, B. Hidding, O.S. Karger, A. Knetsch, A.R. Maier University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany C. Haefner LLNL, Livermore, California, USA B.J. Holzer CERN, Geneva, Switzerland S.M. Hooker University of Oxford, Clarendon Laboratory, Oxford, United Kingdom S.M. Hooker, R. Walczak JAI, Oxford, United Kingdom T. Hosokai Osaka University, Graduate School of Engineering, Osaka, Japan C. Joshi UCLA, Los Angeles, California, USA M. Kaluza HIJ, Jena, Germany S. Karsch LMU, Garching, Germany E. Khazanov, I. Kostyukov IAP/RAS, Nizhny Novgorod, Russia D. Khikhlukha, D. Kocon, G. Korn, A.Y. Molodozhentsev, L. Pribyl ELI-BEAMS, Prague, Czech Republic L. Labate, P. Tomassini CNR/IPP, Pisa, Italy W. Leemans, C.B. Schroeder LBNL, Berkeley, California, USA A. Lifschitz, V. Malka, F. Massimo LOA, Palaiseau, France 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 V. Malka Ecole Polytechnique, Palaiseau, France S. P. D. Mangles, Z. Najmudin, A. A. Sahai Imperial College of Science and Technology, Department of Physics, London, United Kingdom A. Marocchino, A. Mostacci University of Rome La Sapienza, Rome, Italy K. Masaki, Y. Sano JAEA/Kansai, Kyoto, Japan U. Schramm HZDR, Dresden, Germany M.J.V. Streeter, A.G.R. Thomas Cockcroft Institute, Lancaster University, Lancaster, United Kingdom C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France 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 JASRI/SPring-8, Hyogo, Japan A. Zigler The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
	The Horizon 2020 Project EuPRAXIA ('European Plasma Research Accelerator with eXcellence In Applications') aims at producing a design report of a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach and will be used for photon science, high-energy physics (HEP) detector tests, and other applications such as compact X-ray sources for medical imaging or material processing. EuPRAXIA started in November 2015 and will deliver the design report in October 2019. EuPRAXIA aims to be included on the ESFRI roadmap in 2020.
	Slides TUOBB3 [9.269 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOBB3
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TUPAB015	Pulsed Beam Tests at the SANAEM RFQ Beamline	rfq, proton, cavity, emittance	1341
	G. Turemen, Y. Akgun, A. Alacakir, I. Kilic, B. Yasatekin TAEK - SANAEM, Ankara, Turkey F. Ahiska EPROM Electronic Project & Microwave Ind. and Trade Ltd. Co., Ankara, Turkey E. Cicek Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey E. Ergenlik, S. Ogur, E. Sunar, V. Yildiz Bogazici University, Bebek / Istanbul, Turkey G. Unel UCI, Irvine, California, USA
	Funding: Turkish Atomic Energy Authority A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of the 2016 the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.
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TUPAB110	Possible Limits of Plasma Linear Colliders	electron, scattering, emittance, collider	1576
	F. Zimmermann CERN, Geneva, Switzerland
	Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.
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TUPAB111	Energy Distribution and Work Function Measurements for Metal Photocathodes with Measured Levels of Surface Roughness	emittance, electron, FEL, detector	1580
	L.B. Jones, T.S. Beaver, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry Loughborough University, Leicestershre, United Kingdom
	Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453. The minimum achievable emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source which is measureable as the mean longitudinal and transverse energy spreads in the photoemitted electrons. Reducing emittance in an accelerator driving a Free Electron Laser (FEL) delivers significant reduction in the saturation length for an x-ray FEL, reducing machine cost and increasing x-ray beam brightness. There are many parameters which affect the intrinsic emittance of a photocathode. Surface roughness is a significant factor, and consequently the development of techniques to manufacture low roughness photocathodes with optimum emission properties is a priority for the electron source community. In this work, we present transverse energy distribution and work function measurements made using our TESS facility* for electrons emitted from copper and molybdenum photocathodes with differing levels of measured surface roughness. * Proc. FEL '06, THPPH013, 583-586 ** Proc. FEL '13, TUPPS033, 290-293
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TUPAB114	Design Study for a Plasma Undulator Experiment Using Capillary Based Discharge Plasma Source	laser, electron, undulator, experiment	1584
	O. Mete Apsimon, R. Apsimon, Y. Ma, D. Seipt, M.J.V. Streeter, A.G.R. Thomas Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T.H. Pacey, G.X. Xia UMAN, Manchester, United Kingdom
	A plasma undulator is formed when a short laser pulse is injected into plasma off-axis or at an angle that causes the centroid of this laser pulse to oscillate. Ponderomotively driven plasma wake will follow this centroid given that the product of the plasma wave number and the characteristic Rayleigh length of the laser is much larger than one. This oscillating transverse wakefield may work as an undulator forcing particles to follow sinusoidal trajectories and emit synchrotron radiation. In this paper, plans for an experiment are introduced and resulting radiation and injected beam characteristics are discussed. The aforementioned laser centroid oscillations are demonstrated using, EPOCH, a PIC code for laser-plasma interactions.
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TUPIK001	Upgrade of the Two-Screen Measurement Setup in the AWAKE Experiment	proton, wakefield, electron, experiment	1682
	M. Turner TUG/ITP, Graz, Austria V. Clerc, I. Gorgisyan, E. Gschwendtner, S. Mazzoni, A.V. Petrenko CERN, Geneva, Switzerland
	The AWAKE project at CERN uses a self-modulated §I{400}{GeV/c} proton bunch to drive GV/m wakefields in a §I10{m} long plasma with an electron density of n_pe = 7 × 10¹⁴ \rm{electrons/cm}³. We present the upgrade of a proton beam diagnostic to indirectly prove that the bunch self-modulated by imaging defocused protons with two screens downstream the end of the plasma. The two-screen diagnostic has been installed, commissioned and tested in autumn 2016 and limitations were identified. We plan to install an upgraded diagnostics to overcome these limitations.
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TUPIK002	H-, D-, C2-: A Comparison of RF andFilament Powered Volume-Cusp Ion Sources	ion, ion-source, electron, extraction	1685
	S.V. Melanson, M.P. Dehnel, D.E. Potkins D-Pace, Nelson, British Columbia, Canada H.C. McDonald, C. Philpott BSL, Auckland, New Zealand
	Today's industrial ion source applications often require high beam currents with long source lifetime and low maintenance. Filament powered ion sources produce high beam currents but are limited by the short lifetime (~5000 mA*h) of the filament, while RF ion sources with external antennas do not require such maintenance. By changing the filament back plate of our TRIUMF licensed ion source to the ceramic window, planar coil antenna and 13.56 MHz RF amplifier of our University of Jyväskylä licensed ion source, we are able to directly compare the effect of the two technologies for powering sources on negative ion production in volume-cusp ion sources for the case of H-, D- and C2- using our ion source test facility.
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TUPIK006	FLASHForward - A Future-Oriented Wakefield-Accelerator Research and Development Facility at FLASH	electron, laser, diagnostics, injection	1692
	R.T.P. D'Arcy, A. Aschikhin, C. Behrens, S. Bohlen, J. Dale, L. Di Lucchio, M. Felber, B. Foster, L. Goldberg, J.-N. Gruse, Z. Hu, G. Indorg, S. Karstensen, O. S. Kononenko, V. Libov, K. Ludwig, A. Martinez de la Ossa, F. Marutzky, T.J. Mehrling, P. Niknejadi, J. Osterhoff, P. Pourmoussavi, M. Quast, J.-H. Röckemann, L. Schaper, H. Schlarb, B. Schmidt, S. Schröder, J.-P. Schwinkendorf, B. Sheeran, G.E. Tauscher, J. Thesinga, V. Wacker, S. Weichert, S. Wesch, S. Wunderlich, J. Zemella DESY, Hamburg, Germany B. Foster, T.J. Mehrling University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A. Knetsch University of Hamburg, Hamburg, Germany C.A.J. Palmer, M.J.V. Streeter Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	Funding: Helmholtz ARD program and the VH-VI-503 FLASHForward is a beam-driven plasma wakefield acceleration facility, currently under construction at DESY (Hamburg, Germany), aiming at the stable generation of electron beams of several GeV with small energy spread and emittance. High-quality 1 GeV-class electron beams from the free-electron laser FLASH will act as the wake driver. The setup will allow studies of external injection as well as density-downramp injection. With a triangular-shaped driver beam electron energies of up to 5 GeV from a few centimeters of plasma can be anticipated. Particle-In-Cell simulations are used to assess the feasibility of each technique and to predict properties of the accelerated electron bunches. In this contribution the current status of FLASHForward, along with recent experimental developments and upcoming scientific plans, will be reviewed.
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TUPIK007	VisualPIC: A New Data Visualizer and Post-Processor for Particle-in-Cell Codes	simulation, software, interface, GUI	1696
	A. Ferran Pousa, R.W. Aßmann DESY, Hamburg, Germany A. Martinez de la Ossa University of Hamburg, Hamburg, Germany
	Numerical simulations are heavily relied on for evaluating optimal working points with plasma accelerators and for predicting their performance. These simulations produce high volumes of complex data, which is often analyzed by scientists with individually prepared software and analysis tools. As a consequence, there is a lack of a commonly available, quick, complete and easy-to-use data visualizer for Particle-In-Cell simulation codes. VisualPIC is a new application created with the aim of filling that void, providing a graphical user interface with advanced tools for 2D and 3D data visualization, post-processing and particle tracking. The program is developed under the principles of open source and with a modular design, an approach and architecture which allow interested scientists to contribute by adding new features or compatibility for additional simulation codes.
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TUPIK009	External Injection Into a Laser-Driven Plasma Accelerator With Sub-Femtosecond Timing Jitter	laser, electron, injection, acceleration	1699
	A. Ferran Pousa, R.W. Aßmann, R. Brinkmann, A. Martinez de la Ossa DESY, Hamburg, Germany A. Martinez de la Ossa University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The use of external injection in plasma acceleration is attractive due to the high control over the electron beam parameters, which can be tailored to meet the plasma requirements and therefore preserve its quality during acceleration. However, using this technique requires an extremely fine synchronization between the driver and witness beams. In this paper, we present a new scheme for external injection in a laser-driven plasma accelerator that would allow, for the first time, sub-femtosecond timing jitter between laser pulse and electron beam.
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TUPIK010	Investigating the Key Parameters of a Staged Laser- and Particle Driven Plasma Wakefield Accelerator Experiment	laser, electron, wakefield, acceleration	1703
	T. Heinemann, R.W. Aßmann, O. S. Kononenko, A. Martinez de la Ossa DESY, Hamburg, Germany J.P. Couperus, A. Irman, A. Köhler, O. Zarini Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T. Heinemann, B. Hidding USTRAT/SUPA, Glasgow, United Kingdom T. Heinemann University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A. Knetsch University of Hamburg, Hamburg, Germany T. Kurz HZDR, Dresden, Germany U. Schramm TU Dresden, Dresden, Germany
	Plasma wakefield accelerators can be driven by either a powerful laser pulse (LWFA) or a high-current charged particle beam (PWFA). A plasma accelerator combining both schemes consists of a LWFA providing an electron beam which subsequently drives a PWFA in the highly nonlinear regime. This scenario explicitly makes use of the advantages unique to each method, particularly exploiting the capabilities of PWFA schemes to provide high-brightness beams, while the LWFA stage inherently fulfils the demand for compact high-current electron bunches required as PWFA drivers. Effectively, the sub-sequent PWFA stage operates as beam brightness and energy booster of the initial LWFA output, aiming to match the demanding beam quality requirements of accelerator based light sources. We report on numerical studies towards the implementation of a proof-of-principle experiment at the DRACO laser facility at Helmholtz-Zentrum Dresden-Rossendorf (HZDR).
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TUPIK013	Improved Electron Beam Quality from External Injection in Laser-Driven Plasma Acceleration at SINBAD	laser, electron, emittance, acceleration	1707
	M.K. Weikum, R.W. Aßmann, U. Dorda, A. Ferran Pousa, T. Heinemann, B. Marchetti, E.N. Svystun, P.A. Walker DESY, Hamburg, Germany T. Heinemann, F.Y. Li, Z.M. Sheng, M.K. Weikum USTRAT/SUPA, Glasgow, United Kingdom T. Heinemann University of Hamburg, Hamburg, Germany Z.M. Sheng Shanghai Jiao Tong University, Shanghai, People's Republic of China
	External injection into laser wakefield accelerators is one of the possible routes towards high energy, high quality electron beams through plasma acceleration. Among other reasons this is due to the increased control over the electron beam parameters and overall experimental setup when compared to other plasma schemes, such as controlled self-injection. At the future SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY this technique is planned to be tested experimentally through injection and acceleration of a sub-femtosecond electron beam, produced from a conventional RF-injector, with a charge of around 0.7 pC and initial mean energy of 100 MeV at the plasma entrance. A summary of optimisation steps for the potential experimental setup is presented in this paper, including considerations regarding effects of electron beam self-fields and matching of the beam into the plasma stage. The discussion is complemented by first start-to-end simulations of the plasma accelerator setup based on these findings.
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TUPIK017	Next Generation Plasma Cell for PWFA Experiments at PITZ	laser, experiment, electron, Windows	1715
	O. Lishilin, J. Engel, M. Groß, G. Koss, G. Loisch, S. Philipp, R. Schütze, F. Stephan DESY Zeuthen, Zeuthen, Germany R. Brinkmann DESY, Hamburg, Germany F.J. Grüner Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany D. Richter HZB, Berlin, Germany C.B. Schroeder LBNL, Berkeley, California, USA
	A proof-of-principle experiment for the AWAKE experiment is ongoing at the Photo-Injector Test Facility at DESY, Zeuthen site (PITZ). The goal of the experiment is to observe and measure the energy and density self-modulation of a long electron beam passing through a laser-generated Lithium plasma. Key devices of the experiment are a heat pipe based plasma cell, a photocathode laser system which enables production of long electron beams with sharp rising edges and well-developed diagnostics at PITZ, including a transverse deflecting cavity and a high-resolution electron spectrometer. In this report we present the current status of the experiment, including the latest updates of the experimental setup. The plasma cell is a lithium heat pipe oven with inert gas buffers at all input/output ports. An ArF ionization laser is coupled through side ports. Main improvements of the second generation plasma cell are an altered geometry of side arms and a new heat pipe design. Among other updates are an improved ArF laser beamline and new electron windows. We present here measurements of plasma density and homogeneity as well as results of beam transport studies for the experiment. O. Lishilin, M. Gross, et al., Â«First results of the plasma wakefield acceleration experiment at PITZÂ», NIM A, Volume 829, 1 September 2016, Pages 37-42, http://dx.doi.org/10.1016/j.nima.2016.01.005
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TUPIK018	Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ	wakefield, acceleration, experiment, simulation	1718
	G. Loisch, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, M. Krasilnikov, O. Lishilin, A. Oppelt, Y. Renier, T. Rublack, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria G. Asova, R. Brinkmann, A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff DESY, Hamburg, Germany F.J. Grüner CFEL, Hamburg, Germany F.J. Grüner, A. Martinez de la Ossa, T.J. Mehrling University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Plasma wakefield acceleration (PWFA), the acceleration of particles in a plasma wakefield driven by high current-density particle bunches, is one of the most promising candidates for a future compact accelerator technology. A key aspect of this type of acceleration is the ratio between the accelerating fields experienced by a witness beam and the decelerating fields experienced by the drive beam, called the transformer ratio. As for longitudinally symmetrical bunches this ratio is limited by the fundamental theorem of beamloading to 2 in the linear regime, a transformer ratio above this limit is considered high. This can be reached by using a modulated drive bunch or a shaped train of drive bunches. So far, only the latter case has been shown for wakefields in a RF-structure. We show the experimental setup, simulations and first, preliminary results of high transformer ratio acceleration experiments at the Photoinjector Test Facility at DESY in Zeuthen (PITZ). K. L. F. Bane, P. B. Wilson and T. Weiland, AIP Conference Proceedings 127, p. 875, 1984 ** C. Jing et al., Physical Review Letters 98, 144801, 2007
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TUPIK020	Application of Optical Emission Spectroscopy to High Current Proton Sources	proton, electron, ion, diagnostics	1721
	G. Castro, L. Celona, S. Gammino, O. Leonardi, D. Mascali, M. Mazzaglia, E. Naselli, L. Neri, D. Nicolosi, R. Reitano, G. Torrisi INFN/LNS, Catania, Italy F. Leone INAF-OACT, Catania, Italy M. Mazzaglia, R. Reitano Universita Degli Studi Di Catania, Catania, Italy E. Naselli Catania University, Catania, Italy B. Zaniol Consorzio RFX, Padova, Italy
	Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. Instead of other diagnostics, it also allows to characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as testbench of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile along with the perspectives for further upgrades of the OES diagnostics system.
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TUPIK021	Microwave Injection and Coupling Optimization in ECR and MDIS Ion Sources	ion, ion-source, coupling, ECRIS	1724
	G. Torrisi, A.C. Caruso, G. Castro, L. Celona, S. Gammino, O. Leonardi, A. Longhitano, D. Mascali, E. Naselli, L. Neri, G. Sorbello INFN/LNS, Catania, Italy E. Naselli Catania University, Catania, Italy G. Sorbello University of Catania, Catania, Italy
	The fundamental aspect of coupling between microwave and plasma of the Electron Cyclotron Resonance Ion Source (ECRIS) and Microwave Discharge Ion Source (MDIS) is hereinafter treated together with ad hoc microwave-based plasma diagnostics, as a key element for the next progress and variations with respect to the classical ECR heating mechanism. The future challenges for the production of higher-charge states, higher beam intensity, and high absolute ionization efficiency also demand for the exploration of new heating schemes and synergy between experiments and modeling. An overview concerning microwave transport and coupling issues in plasma-based ion sources for particle accelerator will be given in the paper, along with perspectives for the design of next generation sources.
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TUPIK023	Gas-filled Capillaries for Plasma-Based Accelerators	acceleration, electron, laser, background	1731
	F. Filippi INFN-Roma, Roma, Italy M.P. Anania, A. Biagioni, E. Brentegani, E. Chiadroni, M. Ferrario, R. Pompili, S. Romeo INFN/LNF, Frascati (Roma), Italy A. Cianchi INFN-Roma II, Roma, Italy A. Zigler The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
	Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.
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TUPIK024	Study of High Transformer Ratio Plasma Wakefield Acceleration for Accelerator Parameters of SXFEL Using 3D PIC Simulations	simulation, injection, acceleration, wakefield	1734
	S. Huang, J.F. Hua, F. Li, W. Lu, C.H. Pai, Y. Wan, Y.P. Wu, S.Y. Zhou TUB, Beijing, People's Republic of China W. An, C. Joshi, W.B. Mori, X.L. Xu UCLA, Los Angeles, California, USA H.X. Deng, B. Liu, D. Wang, Z. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	High transformer ratio (HTR) Plasma Wakefield Accelerator (PWFA) based on shaped electron bunches is an important topic of plasma wakefield acceleration for future light sources and colliders [1]. To explore the possibility of implementing PWFA at SXFEL, we performed 3D PIC simulations using shaped electron beam parameters obtained by start-to-end beam line simulations [2]. The PIC simulations show that an average transformer ratio around 4 can be maintained for about 10 cm long low density plasma, and the energy gain of the trailing bunch eventually reaches 5.9 GeV. Simulations and analysis are also performed to check the effects of transverse beam size on HTR acceleration. In addition, plasma density downramp injection has also been tested as a possible high brightness injection method for HTR acceleration, and preliminary results will be presented. [] Lu W, An W, Huang C, et al. High Transformer ratio PWFA for Applications on XFELs. Bulletin of the American Physical Society, 2009, 54. [*] Z. Wang, Z. T. Zhao, et al. private communication
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TUPIK026	Simulations of Positron Capture and Acceleration in the Linear Wakefield of Plasma	wakefield, positron, laser, emittance	1737
	M.M. Peng, W. Gai TUB, Beijing, People's Republic of China
	We present the study of positrons capturing dynamics in the wakefield of plasma generated either by a laser or electron beam. Only simplified linear wakefield models were used as first order approximation. By analysing the phase space and beam dynamics, we show that phase space for capturing is rather small, only high brightness beam with very short pulse length can be captured with reasonable rate for wakefields of 1 - 10 GeV/m and wave-length of 100 micron.
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TUPIK031	Driver-Witness-Bunches for Plasma-Wakefield Acceleration at the MAX IV Linear Accelerator	electron, linac, wakefield, simulation	1743
	J. Björklund Svensson, H.E. Ekerfelt, O. Lundh Lund University, Lund, Sweden J. Andersson, F. Curbis, M. Kotur, F. Lindau, E. Mansten, S. Thorin, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden
	Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photo-cathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.
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TUPIK032	AWAKE Proton Beam Commissioning	proton, laser, alignment, experiment	1747
	J.S. Schmidt, D. Barrientos, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, T. Bohl, C. Bracco, S. Cettour Cave, H. Damerau, V. Fedosseev, F. Friebel, S.J. Gessner, A. Goldblatt, E. Gschwendtner, L.K. Jensen, V. Kain, T. Lefèvre, S. Mazzoni, J.C. Molendijk, A. Pardons, C. Pasquino, S.F. Rey, H. Vincke, U. Wehrle CERN, Geneva, Switzerland J.T. Moody MPI-P, München, Germany K. Rieger MPI, Muenchen, Germany
	AWAKE will be the first proton driven plasma wakefield acceleration experiment worldwide. The facility is located in the former CNGS area at CERN and will include a proton, laser and electron beam line merging in a 10 m long plasma cell, which is followed by the experimental diagnostics. In the first phase of the AWAKE physics program, which started at the end of 2016, the effect of the plasma on a high energy proton beam will be studied. A proton bunch is expected to experience the so called self-modulation instability, which leads to the creation of micro-bunches within the long proton bunch. The plasma channel is created in a rubidium vapor via field ionization by a TW laser pulse. This laser beam has to overlap with the proton beam over the full length of the plasma cell, resulting in tight requirements for the stability of the proton beam at the plasma cell in the order of ~ 0.1 mm. In this paper the beam commissioning results of the ~810 m long transfer line for proton bunches with 3·10¹¹ protons/bunch and a momentum of 400 GeV/c will be presented with a focus on the challenges of the parallel operation of the laser and proton beam.
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TUPVA087	ADIGE: The Radioactive Ion Beam Injector of the SPES Project	ion, ECR, rfq, extraction	2281
	A. Galatà, L. Bellan, G. Bisoffi, M. Comunian, L. Martin, M.F. Moisio, A. Palmieri, A. Pisent, G.P. Prete, C. R. Roncolato INFN/LNL, Legnaro (PD), Italy
	The Selective Production of Exotic Species (SPES) project is presently under development at INFN-LNL: aim of this project is the production, ionization and post-acceleration of radioactive ions to perform forefront research in nuclear physics. An ECR-based charge breeder (SPES-CB) will allow post-acceleration of radioactive ions: in particular, the SPES-CB has been designed and developed by LPSC of Grenoble, based on the Phoenix booster. It will be equipped with a complete test bench totally integrated with the SPES beam line: this part of the post-accelerator, together with the newly designed RFQ, composes the so-called ADIGE injector for the superconducting linac ALPI. The injector will employ a unique Medium Resolution Mass Spectrometer (MRMS, R=1/1000), mounted downstream the SPES-CB, in order to avoid the typical drawback of the ECR-based charge breeding technique, that is the beam contamination. This contribution describes the ADIGE injector, with particular attention to the analysis of possible contaminations and the performances expected for the MRMS, showing the beam dynamics calculations for a reference radioactive beam.
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WEOBB2	Beam Commissioning of the High Intensity Proton Source Developed at INFN-LNS for the European Spallation Source	proton, emittance, ion, ion-source	2530
	L. Neri, L. Allegra, A. Amato, G. Calabrese, A.C. Caruso, G. Castro, L. Celona, F. Chines, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, G. Manno, S. Marletta, D. Mascali, M. Mazzaglia, A. Miraglia, S. Passarello, G. Pastore, A. Seminara, A. Spartà, G. Torrisi, S. Vinciguerra INFN/LNS, Catania, Italy
	At the Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.
	Slides WEOBB2 [2.457 MB]
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WEPAB123	A Phase Matching, Adiabatic Accelerator	electron, acceleration, laser, wakefield	2861
	F. Lemery University of Hamburg, Hamburg, Germany K. Flöttmann DESY, Hamburg, Germany F.X. Kärtner MIT, Cambridge, Massachusetts, USA F.X. Kärtner CFEL, Hamburg, Germany P. Piot Fermilab, Batavia, Illinois, USA P. Piot Northern Illinois University, DeKalb, Illinois, USA
	Tabletop accelerators are a thing of the future. Reducing their size will require scaling down electromagnetic wavelengths; however, without correspondingly high field gradients, particles will be more susceptible to phase-slippage – especially at low energy. We investigate how an adiabatically-tapered dielectric-lined waveguide could maintain phase-matching between the accelerating mode and electron bunch. We benchmark our simple model with CST and implement it into ASTRA; finally we provide a first glimpse into the beam dynamics in a phase-matching accelerator.
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WEPAB134	Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices	simulation, emittance, scattering, electron	2891
	J.S. Ellison IIT, Chicago, Illinois, USA P. Snopok Fermilab, Batavia, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy. New computational tools are essential for accurate modeling and simulation of the next generation of muon-based accelerators. One of the crucial physics processes specific to muon accelerators that has not yet been simulated in detail is beam-induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.
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WEPAB137	Cold Muonium Negative Ion Production	ion, electron, target, collider	2898
	V.G. Dudnikov, M.A. Cummings, R.P. Johnson Muons, Inc, Illinois, USA A.V. Dudnikov BINP SB RAS, Novosibirsk, Russia
	Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.
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WEPIK025	Spectral Diagnostics of Argon Plasma in a 10mm Aperture Plasma Window	electron, cathode, vacuum, ion	2978
	P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, Z.X. Yuan, K. Zhu PKU, Beijing, People's Republic of China
	A 10 mm diameter 60 mm long plasma window has been designed and managed to generate arc discharge with argon gas experimentally in Peking University. Based on the previous experiments and simulations, we have measured the electron temperature and density of the plasma via argon spectral diagnostics, and analyzed the conditions to satisfy the criterion of local thermal equilibrium (L.T.E). The electron temperature is in the range of 12000 K to 16000 K. The electron density is in the range of 2.2×10¹⁶ cm^-3 to 3.2×10¹⁶ cm^-3, increasing with discharge current and gas flow rate. The results indicate that our argon plasma is in the L.T.E status. The sealing pressure characteristics of the plasma window is mentioned as well.
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WEPVA001	Electron Injector for Multi-Stage Laser-Driven Plasma Accelerators	electron, laser, simulation, acceleration	3244
	B. Cros, T. Audet, P. Lee, G. Maynard CNRS LPGP Univ Paris Sud, Orsay, France A. Chancé, O. Delferrière, A. Mosnier CEA/DSM/IRFU, France N. Delerue LAL, Orsay, France S. Dobosz-Dufrénoy, A. Maitrallain, P. Monot CEA, Gif-sur-Yvette, France J. Schwindling CEA/IRFU, Gif-sur-Yvette, France A. Specka LLR, Palaiseau, France
	Funding: LAbex PALM, Labex P2IO, Triangle de la Physique, ANR grant Equipex CILEX APOLLON, EU H2020 research and innovation programme under grant agreement No. 653782 EUPRAXIA. An electron injector in the 50-200 MeV range, based on laser wakefield acceleration, is studied in the context of multi-stage laser plasma acceleration. Test experiments carried out at the UHI100 laser facility show that electron bunches in the 100 MeV range, generated by ionization-induced injection mechanism, and accelerated by laser driven wakefield in a mm-scale length plasma can be transported using a magnetic line and precisely analysed. A comparison with simulation results provides insights on electron dynamics and indicates ways to optimize the injector.
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WEPVA012	Laser Proton Accelerator with Improved Repeatability at Peking University	laser, target, proton, acceleration	3275
	Y.R. Shou Peking University, School of Physics, Beijing, People's Republic of China Y.X. Geng, C. Li, L.R.F. Li, Q. Liao, C. Lin, H.Y. Lu, W.J. Ma, P. Wang, M. Wu, X. Xu, X.Q. Yan, Y.Y. Zhao, J.G. Zhu PKU, Beijing, People's Republic of China
	Funding: National Basic Research Program of China (Grant No. 2013CBA01502), National Natural Science Foundation of China (Grants No. 11575011) and National Grand Instrument Project (2012YQ030142). The repeatability of laser proton accelerator is mainly limited by laser plasma interaction, laser target coupling and laser parameter variation. In our recent experiments performed on the Compact Laser Plasma Accelerator at Peking University, gain of proton beams with improved repeatability is demonstrated. In order to control the laser plasma interaction in pre-plasma, cross polarized-wave (XPW) generation technique is employed to provide a laser pulse with a good contrast of 10^-10. A semi-automatic laser and target alignment system with a sensitivity of few micrometers is employed. The repetition rate of the laser proton accelerator is improved to the level of 0.1 Hz which is beneficial to decrease laser parameter variation. The shot-to-shot variation of proton energies is about 9% for a level of confidence of 0.95.
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WEPVA013	Small Size Neutron Generators with Laser Induced Plasma and Electron Conductivity Suppressed by Magnetic Field	laser, neutron, target, electron	3278
	V.I. Rashchikov, S.M. Polozov, A.E. Shikanov MEPhI, Moscow, Russia
	Coaxial neutron tubes generators with transverse dimension less than 0.1 m are discussed. Laser plasma containing deuterons is created at the anode by a focused laser beam. Deuterons from plasma are accelerated by pulse voltage and produces neutrons on cylindrical cathode symmetrically surrounding the anode. Magnetic field was used to suppress knock on parasitic electron current in the accelerating gap. Computer simulation with code SUMA* was fulfilled to investigate output neutron flow dependence on laser produced plasma density, magnetic fields and pulse voltage shapes and amplitudes, cathode and anode materials. The results obtained are in a good agreement with conducted experiments on diode with electron conductivity suppressed by magnetic field produced by permanent magnets*. V.I.Rashchikov, Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 10(18), 50 (1990). **A.E.Shikanov et al., Atomic energy, 119, No.4, 258 (2016).
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WEPVA017	Efficiency Enhancement Induced by a Precursor Electron Bunch in Quasi-Phase Matched Direct Laser Acceleration	electron, ion, focusing, laser	3289
	C.-Y. Hsieh, S.-H. Chen NCU, Chung Li, Taiwan I. Jovanovic NERS-UM, Ann Arbor, Michigan, USA M.W. Lin National Tsing-Hua University (NTHU), Hsinchu, Taiwan
	Funding: This work is supported by the Ministry of Science and Technology in Taiwan by Grant MOST 104-2112-M-008-013-MY3 and the United States Defense Threat Reduction Agency through contract HDTRA1-11-1-0009 Direct laser acceleration (DLA) of an electron bunch can be achieved by utilizing the axial field of a well-guided, radially polarized laser pulse in a density-modulated plasma waveguide. However, the ponderomotive force of a TW-class laser pulse excites a plasma wave that can generate a defocusing electrostatic field, which significantly deteriorates the transverse properties of the injected electron witness bunch. To improve the quality of the accelerated witness bunch, an additional leading electron bunch, termed as a precursor, is introduced to generate ion-focusing force to effectively confine the trailing witness bunch. We conducted three-dimensional particle-in-cell simulations to investigate the effect of bunch charge, transverse size of the precursor, and the axial separation between the precursor and the witness bunch on the efficacy of DLA. Results indicate that the transverse properties of the witness bunch can be maintained and the overall DLA efficiency can be improved, when a favorable ion-focusing force is provided by the precursor. A. G. York, et al., Phys. Rev. Lett. 100, 195001 (2008). ** M. -W. Lin et al., Phys. Plasmas 21, 093109 (2014).
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WEPVA058	Development of HOM Absorber for SuperKEKB	electron, HOM, vacuum, photon	3394
	S. Terui, T. Ishibashi, Y. Suetsugu, Y. Takeuchi, K. Watanabe KEK, Ibaraki, Japan H. Ishizaki, A. Kimura, T. Sawhata Metal Technology Co. Ltd., Ibaraki, Japan
	Higher-order modes (HOM) absorbers are necessary components for recent high-power accelerators in order to prevent beam instabilities (e.g. HOM- Beam Break Up instabilities) or the overheating of vacuum components. Several kinds of absorber materials, such as SiC, ferrite and Kanthal, have been investigated and applied in accelerators. Among these materials, ferrite has been found to be superior to others because of its higher HOM absorbing efficiency. However, because of its low tensile strength and small thermal expansion rate, it cannot be easily bonded to other metals thus limiting its use as a HOM absorber. We reported the success of the fabrication of ferrite-copper-blocks using the spark plasma sintering (SPS)-technique last year. This year we report testing with a high-power RF source and measuring gas desorption rate after baking and secondary electron yield.
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WEPVA141	Ion Cyclotron Resonance Heating Transmitter Opening Switch Upgrade	operation, high-voltage, impedance, resonance	3600
	M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Diversified Technologies Inc. (DTI) has installed a high-power solid-state opening switch upgrade package to replace the mercury ignitron crowbars in the Ion Cyclotron Resonance Heating (ICRH) Transmitters at MIT Plasma Fusion Science Center's (PFSC) Alcator C Mod, a Tokamak-type fusion experimental device. The speed of the series opening switch avoids the large fault currents on the transformer and power feed inherent with a crowbar. This improvement enables re-optimization of the Transformer/Rectifier (T/R) set, ultimately allowing increased power output and increased tetrode reliability. The ratings of the prior high voltage power supply are a compromise between high output power (lower impedance required from the T/R set) and crowbar reliability (higher impedance required from the power supply to limit fault current). DTI's opening switch upgrade safely allows the use of significantly reduced transformer impedance and lower droop, giving increased power as well as improved tube protection. DTI's opening switch kit can readily be adapted to any similar transmitters as an upgrade from a crowbar.
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THPAB013	A Fast Particle Tracking Tool for the Simulation of Dielectric Laser Accelerators	simulation, laser, GPU, space-charge	3716
	F. Mayet, R.W. Aßmann, U. Dorda, W. Kuropka DESY, Hamburg, Germany W. Kuropka, F. Mayet University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Funding: GBMF - Gordon and Betty Moore Foundation In order to simulate the beam dynamics in grating based Dielectric Laser Accelerators (DLA) fully self-consistent PIC codes are usually employed. These codes model the evolution of both the electromagnetic fields inside a laser-driven DLA and the beam phase space very accurately. The main drawback of these codes is that they are computationally very expensive. While the simulation of a single DLA period is feasible with these codes, long multi-period structures cannot be studied without access to HPC clusters. We present a fast particle tracking tool for the simulation of long DLA structures. DLATracker is a parallelized code based on the analytical reconstruction of the in-channel electromagnetic fields and a Boris/Vay-type particle pusher. It computational kernel is written in OpenCL and can run on both CPUs and GPUs. The main code is following a modular approach and is written in Python 2.7. This way the code can be easiliy extended for different use cases. In order to benchmark the code, simulation results are compared to results obtained with the PIC code VSim 7.2.
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THPAB050	Simulations of Beam-Beam Interactions With RF-Track for the AWAKE Primary Beam Lines	electron, proton, simulation, space-charge	3823
	J.S. Schmidt, A. Latina CERN, Geneva, Switzerland
	The AWAKE project at CERN will use a high-energy proton beam at 400 GeV/c to drive wake'elds in a plasma. The amplitude of these wake'elds will be probed by injecting into the plasma a low-energy electron beam (10-20 MeV/c), which will be accelerated to several GeV. Upstream of the plasma cell the two beams will either be transported coaxially or with an o'set of few millimetres for about 6 m. The interaction between the two beams in this beam line has been investigated in the past, with a dedicated simulation code tracking particles under the in'uence of direct space-charge e'ects. These simulations have recently been crosschecked with a new simulation code called RF-Track, developed at CERN to simulate low energy accelerators. RF-Track can track multiple-specie beams at arbitrary energies, taking into account the full electromagnetic particle-to-particle inter-action. For its characteristics RF-Track seems an ideal tool to study the AWAKE two-beam interaction. The results of these studies are presented in this paper and compared to the previous results. The implications for the facility performance are discussed.
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THPAB093	Synchronization of a Photo-Injector and a High Power Laser With Independent Clocks	laser, electron, gun, feedback	3935
	N. Delerue, C. Bruni, K. Cassou, V. Chaumat, R. Chiche, D. Douillet, N. ElKamchi, S. Jenzer, V. Kubytskyi, P. Lepercq, H. Purwar, H. Roesch LAL, Orsay, France E. Baynard, M. Pittman CLUPS, Orsay, France J. Demailly, O. Guilbaud, S. Kazamias, G. Maynard, O. Neveu, D. Ros CNRS LPGP Univ Paris Sud, Orsay, France D. Garzella CEA, Gif-sur-Yvette, France R. Prazeres LCP/CLIO, Orsay, Cedex, France
	Funding: LAL/IN2P3/CNRS and Université Paris-Sud The plasma acceleration project ESCULAP (ElectronS CoUrts pour L'Acc\'el\'eration Plasma) aims at studying electrons injection into a laser plasma accelerator. This requires the injection of short electron bunches generated by the photo injector PHIL (Photo injector at LAL) into a plasma wave by the high power femtosecond Laser LASERIX. As a first step we have studied how to synchronize PHIL and LASERIX. As these two machines had not been initially designed to work together, simple synchronization solutions were not available. We detail here the synchronisation scheme that we have tested and the experimental results obtained.
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THPIK022	Measurements of High-Order Magnetic Field Components of Permanent Quadrupole Magnets for a Laser-Plasma-Driven Undulator X-Ray Source	quadrupole, electron, laser, permanent-magnet	4145
	P. Winkler University of Hamburg, Hamburg, Germany D. Kocon, A.Y. Molodozhentsev ELI-BEAMS, Prague, Czech Republic A.R. Maier CFEL, Hamburg, Germany L. Pribyl Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic M. Trunk University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Laser wakefield acceleration as a novel source of high-energy electron beam is a prominent candidate to drive a next generation of compact light sources. For applications, the electron beam needs to be captured using quadrupole magnets with extremely high field gradient. It allows to preserve properties of the laser-plasma driven electron beam. We designed and manufactured compact permanent quadrupole magnets providing magnetic field gradient up to 510 T/m at an aperture radius of only of a few mm. The Halbach-type quadrupole magents use 12 NdFeB wedges with a remanent magnetic field of 1.2 Tesla. We measured the magnetic field of the permanent magnet quadrupoles using the pulsed-wire and rotating-coil methods. Here, we present an analysis of the magnetic field quality and, in particular, the integrated field gradient and high-order field components. We further discuss the influence of the field imperfections on the electron beam quality and its consequences for application in the transport line of a laser-plasma-driven undulator X-ray source.
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THPVA005	Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens	electron, simulation, experiment, space-charge	4421
	C. Beberweil, M. Droba, S. Klaproth, O. Meusel, D. Noll, H. Podlech, K. Schulte, K.I. Thoma IAP, Frankfurt am Main, Germany S. Gammino, D. Mascali INFN/LNS, Catania, Italy L. Malferrari, A. Montanari, F. Odorici INFN-Bologna, Bologna, Italy
	Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender* was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented. * Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012 ** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015
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THPVA007	Matching Space-charge Dominated Electron Bunches into the Plasma Accelerator at SINBAD	emittance, electron, simulation, focusing	4429
	J. Zhu, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for Laser Wake-Field Acceleration (LWFA) experiments. In order to avoid emittance growth in plasma cells with ultra-high accelerating gradients the injection and transport of electron bunches with beta functions of mm-size or even smaller are required. This kind of bunch is usually space-charged dominated since the energy is low (< 200 MeV) while the peak current is high for allowing the electron bunches to be used for Free Electron-Laser (FEL) generation. We present the beamline design and explore the possible beam parameters at the SINBAD linac by start-to-end simulations.
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Paper

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MOZB1

First Results with the Novel Peta-Watt Laser Acceleration Facility in Dresden

laser, target, electron, acceleration

48

U. Schramm, D. Albach, C. Bernert, S. Bock, F. Brack, J. Branco, M.H. Bussmann, J.P. Couperus, A.D. Debus, C. Eisenmann, M. Garten, R. Gebhardt, S. Grams, U. Helbig, A. Huebl, A. Irman, A. Köhler, J.M. Krämer, S. Kraft, F. Kroll, J. Metzkes, L. Obst, R.G. Pausch, M. Rehwald, H.P. Schlenvoigt, M. Siebold, K. Steiniger, O. Zarini, K. Zeil
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T. Kluge, M. Kuntzsch, U. Lehnert, M. Löser, P. Michel, R. Sauerbrey
HZDR, Dresden, Germany

Applications of laser plasma accelerated particle beams ranging from driving of light sources to radiation therapy require the scaling of beam energy and charge as well as reproducible operating conditions. Both issues have motivated the development of novel table-top class Petawatt laser systems (e.g., 30J pulse energy in 30fs) with unprecedented pulse control, here represented by the Draco-PW system recently commissioned at HZDR Dresden. First results will be presented on laser wakefield electron acceleration where in the beam loading regime high bunch charges in the nC range could be efficiently accelerated with good beam quality, and on proton acceleration where pulsed magnet beam transport ensured depth dose distributions allowing for tumor irradiation in animal models.

Slides MOZB1 [4.059 MB]

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MOPAB039

Development of a Control System Based on Experimental Data for Space Charge Lenses

electron, operation, ion, space-charge

166

S. Klaproth, C. Beberweil, M. Droba, O. Meusel, H. Podlech, B.E.J. Scheible, K. Schulte, K.I. Thoma, C. Wagner
IAP, Frankfurt am Main, Germany

Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past *,**. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained.
* O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006

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MOPAB049

Development of a Focusing System for the AXSIS Project

linac, solenoid, quadrupole, focusing

203

T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

In this paper, we investigate with ASTRA simulations the achievable performances for several focusing systems considered in the AXSIS project. We focus our attention on the requirements in terms of position of the focal point and bunch transverse size at this point. We show that they cannot be fulfilled with a solenoid resistive electro-magnet, but that it is possible when using a solenoid permanent magnet. The use of a quadrupole doublet proves to be adequate to fulfil the requirement on the position of the focal point and be very close to the one on the bunch transverse size, which could possibly be achieved by a further optimization of the parameters of the doublet. Finally, we also investigate the possibility to use an active plasma lens, showing that it could easily fulfil the requirements but that several points must be carefully studied before considering its implementation.

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MOPAB119

Beam Instrumentation Developments for the Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

proton, electron, laser, electronics

404

S. Mazzoni, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, S. Burger, F.S. Domingues Sousa, E. Effinger, J. Emery, A. Goldblatt, I. Gorgisyan, E. Gschwendtner, A. Guerrero, L.K. Jensen, T. Lefèvre, D. Medina, B. Moser, G. Schneider, L. Søby, M. Turner, M. Vicente Romero, M. Wendt
CERN, Geneva, Switzerland
B. Biskup
Czech Technical University, Prague 6, Czech Republic
M. Turner
TUG/ITP, Graz, Austria
V.A. Verzilov
TRIUMF, Vancouver, Canada

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN aims to develop a proof-of-principle electron accelerator based on proton driven plasma wake-field acceleration. The core of AWAKE is a 10 metre long plasma cell filled with Rubidium vapour in which single, 400 GeV, proton bunches extracted from the CERN Super Proton Synchrotron (SPS) generate a strong plasma wakefield. The plasma is seeded using a femtosecond pulsed Ti:Sapphire laser. The aim of the experiment is to inject low energy electrons onto the plasma wake and accelerate them over this short distance to an energy of several GeV. To achieve its commissioning goals, AWAKE requires the precise measurement of the position and transverse profile of the laser, proton and electron beams as well as their temporal synchronisation. This contribution will present the beam instrumentation systems designed for AWAKE and their performance during the 2016 proton beam commissioning period.

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MOPAB153

R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

cavity, electron, ion, experiment

491

K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA
Q. Liu
Case Western Reserve University, Cleveland, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764.
A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.

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MOPIK016

Sub-Picosecond Beam Production for External Injection Into Plasma Experiments

gun, electron, linac, simulation

531

O. Mete Apsimon, R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: This work has been funded by STFC.
Applications of plasmas in accelerators benefit from short probe bunches comparable to plasma wavelength due to currently achievable plasma wake profiles. In plasma acceleration case, high capture efficiency within a narrow energy spectrum can be achieved when a sub-picosecond to femtosecond witness bunch injected behind the driver pulse at the high electric field region. A start-to-end simulation study was performed for parametric optimisation of an rf photoinjector to provide a short witness bunch for plasma applications in accelerators. An rf photoinjector is a laser-driven, high brightness and robust electron source that can provide stability and flexibility provided by today's advanced laser and rf technologies.

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MOPIK032

Commissioning of the AISHa Ion Source at INFN-LNS

ion, ion-source, injection, operation

570

L. Celona, G. Castro, F. Chines, G. Costa, S. Gammino, O. Leonardi, S. Marletta, D. Mascali, A. Maugeri, L. Neri, F. Noto, S. Passarello, G. Pastore, A. Seminara, G. Torrisi, S. Vinciguerra
INFN/LNS, Catania, Italy
S. Di Martino, P. Nicotra
Si.A.Tel SRL, Catania, Italy

At INFN-LNS the commissioning of the AISHa superconducting ECRIS started in November 2016. Highly charged ion beams with low ripple, high stability and high reproducibility are the most important features for the ongoing commissioning. In this work, we will show the preliminary results of a parametric study on the extracted current/beam in order to minimize the emittance and increase the brightness taking advantage by its hybrid magnetic system and by a fine frequency tuning system.

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MOPIK052

Generation of Highly-Charged Carbon Ions from Thin Foil Target

target, ion, laser, heavy-ion

635

T. Kanesue, S. Ikeda, M. Okamura
BNL, Upton, Long Island, New York, USA
Y. Saito
Sokendai, Ibaraki, Japan

Funding: This work was supported by the U.S. Department of Energy and National Aeronautics and Space Administration.
Generation of highly-charged heavy ions such as fully stripped C⁶⁺ of more than hundreds mA of beam current can be possible only with a laser ablation ion source (LIS). Heavy ions are produced from a solid target irradiated by a pulsed high power laser. Recent study showed that only sub-micron range of surface layer contributes for the generation of highly-charged heavy ions. In this paper, we experimentally investigated the difference of the performance of highly-charged carbon ion production from graphite targets of different thickness (25, 70, 254, and 3000 'm) to seek the possibility of a rolled target to overcome the limitation of a target lifetime.

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MOPIK053

Design Study of High Repetition Rate Laser Ion Source for High Power Beam Production

target, laser, ion, heavy-ion

638

T. Kanesue, S. Ikeda, M. Okamura
BNL, Upton, Long Island, New York, USA
Y. Saito
Sokendai, Ibaraki, Japan

Funding: This work was supported by the U.S. Department of Energy and National Aeronautics and Space Administration.
We are studying a laser ion source (LIS) for a high average beam power heavy ion beam production. A LIS is the most intense source of pulsed highly-charged ions using a laser ablation scheme. By increasing the repetition rate, a LIS based heavy ion beam would approach the average beam power based on a low beam current and continuous beam regime. In addition, a high-repetition-rate LIS can be used as a heavy ion source for a medical accelerator with spot scanning technique. This paper will describe the requirements to realize the high repetition rate operation.

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MOPVA082

PLASMA PROCESSING R&D OF THE 1.3 GHZ SINGLE-CELL SRF CAVITY AT IMP

cavity, SRF, accelerating-gradient, electromagnetic-fields

1055

L. Yang, L. Chen, Y. He, S.C. Huang, C.X. Li, C.L. Li, Y.M. Li, L. Lu, A. Shi, L.P. Sun, A.D. Wu, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

The China-Accelerator Driven Sub-critical System (C-ADS) injector II has already commissioned with a CW 1 mA and a pulsed 10 mA proton beam. The beam energy achieved 10 MeV. The superconducting linac (SCL) is routinely operating at 4.7 MV/m average accelerating gradient in the low-beta cryomodules. Field emission and surface contaminants of the SCL limit the gradient in-crease in the beam commissioning. Hence, in order to increase the SCL accelerating gradient, reduce field emis-sion and remove surface pollutants, in-situ plasma pro-cessing R&D in a 1.3 GHz single-cell SRF cavity has being studied. In this paper, the current effort of plasma processing R&D in a 1.3 GHz single-cell SRF cavity will be presented in details and the future plan will be also reported.

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MOPVA100

Atomic Layer Deposition of Niobium Nitride from Different Precursors

niobium, experiment, controls, simulation

1094

P. Pizzol, P. Chalker, J.W. Roberts, J. Wrench
The University of Liverpool, Liverpool, United Kingdom
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Advancements in technology have taken bulk niobium cavities close to their theoretical operational limits of 45 MV/m, pushing the research to explore novel materials, such as niobium based alloys . Theoretical studies suggest that a composite material composed of alternative superconductor / insulator multilayers would surpass the bulk niobium limits. Chemical vapour deposition (CVD) can deposit mi-crons thick Nb films in less than an hour, at the expense of precise thickness control. Atomic layer deposition (ALD), instead, even if considerably slower than CVD can be used in applications where the thickness of the deposited layers needs to be controlled with a resolution down to the nanometer. This article presents the preliminary results obtained by using plasma assisted ALD techniques to deposit NbN based compounds starting from chlorinated precursors and organic ones, and the design for a new deposition system currently being built at the Daresbury Laboratories.

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TUYB1

First Measurements of Trojan Horse Injection in a Plasma Wakefield Accelerator

laser, electron, wakefield, injection

1252

B. Hidding, A. Beaton, A.F. Habib, T. Heinemann, G.G. Manahan, P. Scherkl, A. Sutherland, D. Ullmann
USTRAT/SUPA, Glasgow, United Kingdom
E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
E. Adli, S.J. Gessner
CERN, Geneva, Switzerland
G. Andonian, A. Deng, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
G. Andonian
RadiaBeam, Santa Monica, California, USA
A. Beaton, A.F. Habib, T. Heinemann, B. Hidding, G.G. Manahan, P. Scherkl, A. Sutherland, D. Ullmann
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colorado, USA
J.R. Cary
Tech-X, Boulder, Colorado, USA
C.I. Clarke, S.Z. Green, M.J. Hogan, B.D. O'Shea, V. Yakimenko
SLAC, Menlo Park, California, USA
M. Downer, R. Zgadzaj
The University of Texas at Austin, Austin, Texas, USA
T. Heinemann, A. Knetsch
DESY, Hamburg, Germany
T. Heinemann, G. Wittig
University of Hamburg, Hamburg, Germany
O.S. Karger
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
M.D. Litos
Colorado University at Boulder, Boulder, Colorado, USA
J.D.A. Smith
TXUK, Warrington, United Kingdom

Funding: Work supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
Plasma accelerators support accelerating fields of 100's of GV/m over meter-scale distances and routinely produce femtosecond-scale, multi-kA electron bunches. The so called Trojan Horse underdense photocathode plasma wakefield acceleration scheme combines state-of-the-art accelerator technology with laser and plasma methods and paves the way to improve beam quality as regards emittance and energy spread by many orders of magnitude. Electron beam brightness levels exceeding 10²⁰ Am^-2 rad^-2 may be reached, and the tunability allows for multi-GeV energies, designer bunches and energy spreads <0.05% in a single plasma accelerator stage. The talk will present results of the international E210 multi-year experimental program at SLAC FACET, which culminated in successful first demonstration of the Trojan Horse method during FACET's final experimental run in 2016. Enabling implications for applications, including high performance plasma-based 5th generation light sources such as hard x-ray FEL's, for which start-to-end simulations are presented, and for high energy physics are discussed.

Slides TUYB1 [19.089 MB]

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TUOBB1

Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper

electron, laser, experiment, linac

1258

Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou
TUB, Beijing, People's Republic of China

The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[*]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators.
[*] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports

Slides TUOBB1 [10.555 MB]

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TUOBB2

Starting Up the AWAKE Experiment at CERN

proton, laser, electron, experiment

1261

E. Gschwendtner
CERN, Geneva, Switzerland

AWAKE, the Advanced Proton Driven Plasma Wake-field Acceleration Experiment at CERN was approved in 2013. The facility was commissioned in 2016 to perform first experiments to demonstrate the self-modulation in-stability (SMI) of a 400 GeV/c SPS proton bunch in a 10 m long Rubidium plasma cell. The plasma is created in Rb vapor via field ionization by a TW laser pulse. In the second phase starting late 2017, the proton driven plasma wakefield will be probed with an externally injected 10 ' 20 MeV/c electron beam. This paper gives an overview of the AWAKE facility, describes the successful commissioning of the laser and proton beam line, the plasma cell and diagnostics and shows the successful synchronization of the proton beam with the laser at the few ps level so that the facility is ready for the SMI physics runs. In addition the status of the electron acceleration exper-iment for late 2017 will be presented.

Slides TUOBB2 [3.513 MB]

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TUOBB3

HORIZON 2020 EuPRAXIA Design Study

laser, electron, acceleration, radiation

1265

P.A. Walker, R.W. Aßmann, J. Bödewadt, R. Brinkmann, J. Dale, U. Dorda, A. Ferran Pousa, A.F. Habib, T. Heinemann, O. S. Kononenko, C. Lechner, B. Marchetti, A. Martinez de la Ossa, T.J. Mehrling, P. Niknejadi, J. Osterhoff, K. Poder, E.N. Svystun, G.E. Tauscher, M.K. Weikum, J. Zhu
DESY, Hamburg, Germany
D. Alesini, M.P. Anania, F.G. Bisesto, E. Chiadroni, M. Croia, M. Ferrario, F. Filippi, A. Gallo, A. Mostacci, R. Pompili, S. Romeo, J. Scifo, C. Vaccarezza, F. Villa
INFN/LNF, Frascati (Roma), Italy
A.S. Alexandrova, R.B. Fiorito, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
A.S. Alexandrova, R.B. Fiorito, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N.E. Andreev, D. Pugacheva
JIHT RAS, Moscow, Russia
T. Audet, B. Cros, G. Maynard
CNRS LPGP Univ Paris Sud, Orsay, France
A. Bacci, D. Giove, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
I.F. Barna, M.A. Pocsai
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
A. Beaton, P. Delinikolas, B. Hidding, D.A. Jaroszynski, F.Y. Li, G.G. Manahan, P. Scherkl, Z.M. Sheng, M.K. Weikum
USTRAT/SUPA, Glasgow, United Kingdom
A. Beck, A. Specka
LLR, Palaiseau, France
A. Beluze, M. Mathieu, D.N. Papadopoulos
LULI, Palaiseau, France
A. Bernhard, E. Bründermann, A.-S. Müller
KIT, Karlsruhe, Germany
S. Bielawski
PhLAM/CERLA, Villeneuve d'Ascq, France
F. Brandi, G. Bussolino, L.A. Gizzi, P. Koester, B. Patrizi, G. Toci, M. Vannini
INO-CNR, Pisa, Italy
O. Bringer, A. Chancé, O. Delferrière, J. Fils, D. Garzella, P. Gastinel, X. Li, A. Mosnier, P.A.P. Nghiem, J. Schwindling, C. Simon
CEA/IRFU, Gif-sur-Yvette, France
M. Büscher, A. Lehrach
FZJ, Jülich, Germany
M. Chen, L. Yu
Shanghai Jiao Tong University, Shanghai, People's Republic of China
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
J.A. Clarke, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.-E. Couprie
SOLEIL, Gif-sur-Yvette, France
G. Dattoli, F. Nguyen
ENEA C.R. Frascati, Frascati (Roma), Italy
N. Delerue
LAL, Orsay, France
J.M. Dias, R.A. Fonseca, J.L. Martins, L.O. Silva, U. Sinha, J. Vieira
IPFN, Lisbon, Portugal
K. Ertel, M. Galimberti, R. Pattathil, D. Symes
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Fils
GSI, Darmstadt, Germany
A. Giribono
INFN-Roma, Roma, Italy
L.A. Gizzi
INFN-Pisa, Pisa, Italy
F.J. Grüner, A.R. Maier
CFEL, Hamburg, Germany
F.J. Grüner, T. Heinemann, B. Hidding, O.S. Karger, A. Knetsch, A.R. Maier
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
C. Haefner
LLNL, Livermore, California, USA
B.J. Holzer
CERN, Geneva, Switzerland
S.M. Hooker
University of Oxford, Clarendon Laboratory, Oxford, United Kingdom
S.M. Hooker, R. Walczak
JAI, Oxford, United Kingdom
T. Hosokai
Osaka University, Graduate School of Engineering, Osaka, Japan
C. Joshi
UCLA, Los Angeles, California, USA
M. Kaluza
HIJ, Jena, Germany
S. Karsch
LMU, Garching, Germany
E. Khazanov, I. Kostyukov
IAP/RAS, Nizhny Novgorod, Russia
D. Khikhlukha, D. Kocon, G. Korn, A.Y. Molodozhentsev, L. Pribyl
ELI-BEAMS, Prague, Czech Republic
L. Labate, P. Tomassini
CNR/IPP, Pisa, Italy
W. Leemans, C.B. Schroeder
LBNL, Berkeley, California, USA
A. Lifschitz, V. Malka, F. Massimo
LOA, Palaiseau, France
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
V. Malka
Ecole Polytechnique, Palaiseau, France
S. P. D. Mangles, Z. Najmudin, A. A. Sahai
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
A. Marocchino, A. Mostacci
University of Rome La Sapienza, Rome, Italy
K. Masaki, Y. Sano
JAEA/Kansai, Kyoto, Japan
U. Schramm
HZDR, Dresden, Germany
M.J.V. Streeter, A.G.R. Thomas
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
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
JASRI/SPring-8, Hyogo, Japan
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

The Horizon 2020 Project EuPRAXIA ('European Plasma Research Accelerator with eXcellence In Applications') aims at producing a design report of a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach and will be used for photon science, high-energy physics (HEP) detector tests, and other applications such as compact X-ray sources for medical imaging or material processing. EuPRAXIA started in November 2015 and will deliver the design report in October 2019. EuPRAXIA aims to be included on the ESFRI roadmap in 2020.

Slides TUOBB3 [9.269 MB]

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TUPAB015

Pulsed Beam Tests at the SANAEM RFQ Beamline

rfq, proton, cavity, emittance

1341

G. Turemen, Y. Akgun, A. Alacakir, I. Kilic, B. Yasatekin
TAEK - SANAEM, Ankara, Turkey
F. Ahiska
EPROM Electronic Project & Microwave Ind. and Trade Ltd. Co., Ankara, Turkey
E. Cicek
Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey
E. Ergenlik, S. Ogur, E. Sunar, V. Yildiz
Bogazici University, Bebek / Istanbul, Turkey
G. Unel
UCI, Irvine, California, USA

Funding: Turkish Atomic Energy Authority
A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of the 2016 the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.

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TUPAB110

Possible Limits of Plasma Linear Colliders

electron, scattering, emittance, collider

1576

F. Zimmermann
CERN, Geneva, Switzerland

Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.

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TUPAB111

Energy Distribution and Work Function Measurements for Metal Photocathodes with Measured Levels of Surface Roughness

emittance, electron, FEL, detector

1580

L.B. Jones, T.S. Beaver, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
Loughborough University, Leicestershre, United Kingdom

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
The minimum achievable emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source which is measureable as the mean longitudinal and transverse energy spreads in the photoemitted electrons. Reducing emittance in an accelerator driving a Free Electron Laser (FEL) delivers significant reduction in the saturation length for an x-ray FEL, reducing machine cost and increasing x-ray beam brightness. There are many parameters which affect the intrinsic emittance of a photocathode. Surface roughness is a significant factor*, and consequently the development of techniques to manufacture low roughness photocathodes with optimum emission properties is a priority for the electron source community. In this work, we present transverse energy distribution and work function measurements made using our TESS facility** for electrons emitted from copper and molybdenum photocathodes with differing levels of measured surface roughness.
* Proc. FEL '06, THPPH013, 583-586
** Proc. FEL '13, TUPPS033, 290-293

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TUPAB114

Design Study for a Plasma Undulator Experiment Using Capillary Based Discharge Plasma Source

laser, electron, undulator, experiment

1584

O. Mete Apsimon, R. Apsimon, Y. Ma, D. Seipt, M.J.V. Streeter, A.G.R. Thomas
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.H. Pacey, G.X. Xia
UMAN, Manchester, United Kingdom

A plasma undulator is formed when a short laser pulse is injected into plasma off-axis or at an angle that causes the centroid of this laser pulse to oscillate. Ponderomotively driven plasma wake will follow this centroid given that the product of the plasma wave number and the characteristic Rayleigh length of the laser is much larger than one. This oscillating transverse wakefield may work as an undulator forcing particles to follow sinusoidal trajectories and emit synchrotron radiation. In this paper, plans for an experiment are introduced and resulting radiation and injected beam characteristics are discussed. The aforementioned laser centroid oscillations are demonstrated using, EPOCH, a PIC code for laser-plasma interactions.

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TUPIK001

Upgrade of the Two-Screen Measurement Setup in the AWAKE Experiment

proton, wakefield, electron, experiment

1682

M. Turner
TUG/ITP, Graz, Austria
V. Clerc, I. Gorgisyan, E. Gschwendtner, S. Mazzoni, A.V. Petrenko
CERN, Geneva, Switzerland

The AWAKE project at CERN uses a self-modulated §I{400}{GeV/c} proton bunch to drive GV/m wakefields in a §I10{m} long plasma with an electron density of n_pe = 7 × 10¹⁴ \rm{electrons/cm}³. We present the upgrade of a proton beam diagnostic to indirectly prove that the bunch self-modulated by imaging defocused protons with two screens downstream the end of the plasma. The two-screen diagnostic has been installed, commissioned and tested in autumn 2016 and limitations were identified. We plan to install an upgraded diagnostics to overcome these limitations.

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TUPIK002

H-, D-, C2-: A Comparison of RF andFilament Powered Volume-Cusp Ion Sources

ion, ion-source, electron, extraction

1685

S.V. Melanson, M.P. Dehnel, D.E. Potkins
D-Pace, Nelson, British Columbia, Canada
H.C. McDonald, C. Philpott
BSL, Auckland, New Zealand

Today's industrial ion source applications often require high beam currents with long source lifetime and low maintenance. Filament powered ion sources produce high beam currents but are limited by the short lifetime (~5000 mA*h) of the filament, while RF ion sources with external antennas do not require such maintenance. By changing the filament back plate of our TRIUMF licensed ion source to the ceramic window, planar coil antenna and 13.56 MHz RF amplifier of our University of Jyväskylä licensed ion source, we are able to directly compare the effect of the two technologies for powering sources on negative ion production in volume-cusp ion sources for the case of H-, D- and C2- using our ion source test facility.

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TUPIK006

FLASHForward - A Future-Oriented Wakefield-Accelerator Research and Development Facility at FLASH

electron, laser, diagnostics, injection

1692

R.T.P. D'Arcy, A. Aschikhin, C. Behrens, S. Bohlen, J. Dale, L. Di Lucchio, M. Felber, B. Foster, L. Goldberg, J.-N. Gruse, Z. Hu, G. Indorg, S. Karstensen, O. S. Kononenko, V. Libov, K. Ludwig, A. Martinez de la Ossa, F. Marutzky, T.J. Mehrling, P. Niknejadi, J. Osterhoff, P. Pourmoussavi, M. Quast, J.-H. Röckemann, L. Schaper, H. Schlarb, B. Schmidt, S. Schröder, J.-P. Schwinkendorf, B. Sheeran, G.E. Tauscher, J. Thesinga, V. Wacker, S. Weichert, S. Wesch, S. Wunderlich, J. Zemella
DESY, Hamburg, Germany
B. Foster, T.J. Mehrling
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A. Knetsch
University of Hamburg, Hamburg, Germany
C.A.J. Palmer, M.J.V. Streeter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Funding: Helmholtz ARD program and the VH-VI-503
FLASHForward is a beam-driven plasma wakefield acceleration facility, currently under construction at DESY (Hamburg, Germany), aiming at the stable generation of electron beams of several GeV with small energy spread and emittance. High-quality 1 GeV-class electron beams from the free-electron laser FLASH will act as the wake driver. The setup will allow studies of external injection as well as density-downramp injection. With a triangular-shaped driver beam electron energies of up to 5 GeV from a few centimeters of plasma can be anticipated. Particle-In-Cell simulations are used to assess the feasibility of each technique and to predict properties of the accelerated electron bunches. In this contribution the current status of FLASHForward, along with recent experimental developments and upcoming scientific plans, will be reviewed.

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TUPIK007

VisualPIC: A New Data Visualizer and Post-Processor for Particle-in-Cell Codes

simulation, software, interface, GUI

1696

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

Numerical simulations are heavily relied on for evaluating optimal working points with plasma accelerators and for predicting their performance. These simulations produce high volumes of complex data, which is often analyzed by scientists with individually prepared software and analysis tools. As a consequence, there is a lack of a commonly available, quick, complete and easy-to-use data visualizer for Particle-In-Cell simulation codes. VisualPIC is a new application created with the aim of filling that void, providing a graphical user interface with advanced tools for 2D and 3D data visualization, post-processing and particle tracking. The program is developed under the principles of open source and with a modular design, an approach and architecture which allow interested scientists to contribute by adding new features or compatibility for additional simulation codes.

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TUPIK009

External Injection Into a Laser-Driven Plasma Accelerator With Sub-Femtosecond Timing Jitter

laser, electron, injection, acceleration

1699

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

The use of external injection in plasma acceleration is attractive due to the high control over the electron beam parameters, which can be tailored to meet the plasma requirements and therefore preserve its quality during acceleration. However, using this technique requires an extremely fine synchronization between the driver and witness beams. In this paper, we present a new scheme for external injection in a laser-driven plasma accelerator that would allow, for the first time, sub-femtosecond timing jitter between laser pulse and electron beam.

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TUPIK010

Investigating the Key Parameters of a Staged Laser- and Particle Driven Plasma Wakefield Accelerator Experiment

laser, electron, wakefield, acceleration

1703

T. Heinemann, R.W. Aßmann, O. S. Kononenko, A. Martinez de la Ossa
DESY, Hamburg, Germany
J.P. Couperus, A. Irman, A. Köhler, O. Zarini
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T. Heinemann, B. Hidding
USTRAT/SUPA, Glasgow, United Kingdom
T. Heinemann
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A. Knetsch
University of Hamburg, Hamburg, Germany
T. Kurz
HZDR, Dresden, Germany
U. Schramm
TU Dresden, Dresden, Germany

Plasma wakefield accelerators can be driven by either a powerful laser pulse (LWFA) or a high-current charged particle beam (PWFA). A plasma accelerator combining both schemes consists of a LWFA providing an electron beam which subsequently drives a PWFA in the highly nonlinear regime. This scenario explicitly makes use of the advantages unique to each method, particularly exploiting the capabilities of PWFA schemes to provide high-brightness beams, while the LWFA stage inherently fulfils the demand for compact high-current electron bunches required as PWFA drivers. Effectively, the sub-sequent PWFA stage operates as beam brightness and energy booster of the initial LWFA output, aiming to match the demanding beam quality requirements of accelerator based light sources. We report on numerical studies towards the implementation of a proof-of-principle experiment at the DRACO laser facility at Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

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TUPIK013

Improved Electron Beam Quality from External Injection in Laser-Driven Plasma Acceleration at SINBAD

laser, electron, emittance, acceleration

1707

M.K. Weikum, R.W. Aßmann, U. Dorda, A. Ferran Pousa, T. Heinemann, B. Marchetti, E.N. Svystun, P.A. Walker
DESY, Hamburg, Germany
T. Heinemann, F.Y. Li, Z.M. Sheng, M.K. Weikum
USTRAT/SUPA, Glasgow, United Kingdom
T. Heinemann
University of Hamburg, Hamburg, Germany
Z.M. Sheng
Shanghai Jiao Tong University, Shanghai, People's Republic of China

External injection into laser wakefield accelerators is one of the possible routes towards high energy, high quality electron beams through plasma acceleration. Among other reasons this is due to the increased control over the electron beam parameters and overall experimental setup when compared to other plasma schemes, such as controlled self-injection. At the future SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY this technique is planned to be tested experimentally through injection and acceleration of a sub-femtosecond electron beam, produced from a conventional RF-injector, with a charge of around 0.7 pC and initial mean energy of 100 MeV at the plasma entrance. A summary of optimisation steps for the potential experimental setup is presented in this paper, including considerations regarding effects of electron beam self-fields and matching of the beam into the plasma stage. The discussion is complemented by first start-to-end simulations of the plasma accelerator setup based on these findings.

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TUPIK017

Next Generation Plasma Cell for PWFA Experiments at PITZ

laser, experiment, electron, Windows

1715

O. Lishilin, J. Engel, M. Groß, G. Koss, G. Loisch, S. Philipp, R. Schütze, F. Stephan
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann
DESY, Hamburg, Germany
F.J. Grüner
Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany
D. Richter
HZB, Berlin, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA

A proof-of-principle experiment for the AWAKE experiment is ongoing at the Photo-Injector Test Facility at DESY, Zeuthen site (PITZ). The goal of the experiment is to observe and measure the energy and density self-modulation of a long electron beam passing through a laser-generated Lithium plasma*. Key devices of the experiment are a heat pipe based plasma cell, a photocathode laser system which enables production of long electron beams with sharp rising edges and well-developed diagnostics at PITZ, including a transverse deflecting cavity and a high-resolution electron spectrometer. In this report we present the current status of the experiment, including the latest updates of the experimental setup. The plasma cell is a lithium heat pipe oven with inert gas buffers at all input/output ports. An ArF ionization laser is coupled through side ports. Main improvements of the second generation plasma cell are an altered geometry of side arms and a new heat pipe design. Among other updates are an improved ArF laser beamline and new electron windows. We present here measurements of plasma density and homogeneity as well as results of beam transport studies for the experiment.
*O. Lishilin, M. Gross, et al., Â«First results of the plasma wakefield acceleration experiment at PITZÂ», NIM A, Volume 829, 1 September 2016, Pages 37-42, http://dx.doi.org/10.1016/j.nima.2016.01.005

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TUPIK018

Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ

wakefield, acceleration, experiment, simulation

1718

G. Loisch, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, M. Krasilnikov, O. Lishilin, A. Oppelt, Y. Renier, T. Rublack, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
G. Asova, R. Brinkmann, A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff
DESY, Hamburg, Germany
F.J. Grüner
CFEL, Hamburg, Germany
F.J. Grüner, A. Martinez de la Ossa, T.J. Mehrling
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Plasma wakefield acceleration (PWFA), the acceleration of particles in a plasma wakefield driven by high current-density particle bunches, is one of the most promising candidates for a future compact accelerator technology. A key aspect of this type of acceleration is the ratio between the accelerating fields experienced by a witness beam and the decelerating fields experienced by the drive beam, called the transformer ratio. As for longitudinally symmetrical bunches this ratio is limited by the fundamental theorem of beamloading to 2 in the linear regime*, a transformer ratio above this limit is considered high. This can be reached by using a modulated drive bunch or a shaped train of drive bunches. So far, only the latter case has been shown for wakefields in a RF-structure**. We show the experimental setup, simulations and first, preliminary results of high transformer ratio acceleration experiments at the Photoinjector Test Facility at DESY in Zeuthen (PITZ).
* K. L. F. Bane, P. B. Wilson and T. Weiland, AIP Conference Proceedings 127, p. 875, 1984
** C. Jing et al., Physical Review Letters 98, 144801, 2007

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TUPIK020

Application of Optical Emission Spectroscopy to High Current Proton Sources

proton, electron, ion, diagnostics

1721

G. Castro, L. Celona, S. Gammino, O. Leonardi, D. Mascali, M. Mazzaglia, E. Naselli, L. Neri, D. Nicolosi, R. Reitano, G. Torrisi
INFN/LNS, Catania, Italy
F. Leone
INAF-OACT, Catania, Italy
M. Mazzaglia, R. Reitano
Universita Degli Studi Di Catania, Catania, Italy
E. Naselli
Catania University, Catania, Italy
B. Zaniol
Consorzio RFX, Padova, Italy

Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. Instead of other diagnostics, it also allows to characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as testbench of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile along with the perspectives for further upgrades of the OES diagnostics system.

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TUPIK021

Microwave Injection and Coupling Optimization in ECR and MDIS Ion Sources

ion, ion-source, coupling, ECRIS

1724

G. Torrisi, A.C. Caruso, G. Castro, L. Celona, S. Gammino, O. Leonardi, A. Longhitano, D. Mascali, E. Naselli, L. Neri, G. Sorbello
INFN/LNS, Catania, Italy
E. Naselli
Catania University, Catania, Italy
G. Sorbello
University of Catania, Catania, Italy

The fundamental aspect of coupling between microwave and plasma of the Electron Cyclotron Resonance Ion Source (ECRIS) and Microwave Discharge Ion Source (MDIS) is hereinafter treated together with ad hoc microwave-based plasma diagnostics, as a key element for the next progress and variations with respect to the classical ECR heating mechanism. The future challenges for the production of higher-charge states, higher beam intensity, and high absolute ionization efficiency also demand for the exploration of new heating schemes and synergy between experiments and modeling. An overview concerning microwave transport and coupling issues in plasma-based ion sources for particle accelerator will be given in the paper, along with perspectives for the design of next generation sources.

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TUPIK023

Gas-filled Capillaries for Plasma-Based Accelerators

acceleration, electron, laser, background

1731

F. Filippi
INFN-Roma, Roma, Italy
M.P. Anania, A. Biagioni, E. Brentegani, E. Chiadroni, M. Ferrario, R. Pompili, S. Romeo
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

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TUPIK024

Study of High Transformer Ratio Plasma Wakefield Acceleration for Accelerator Parameters of SXFEL Using 3D PIC Simulations

simulation, injection, acceleration, wakefield

1734

S. Huang, J.F. Hua, F. Li, W. Lu, C.H. Pai, Y. Wan, Y.P. Wu, S.Y. Zhou
TUB, Beijing, People's Republic of China
W. An, C. Joshi, W.B. Mori, X.L. Xu
UCLA, Los Angeles, California, USA
H.X. Deng, B. Liu, D. Wang, Z. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

High transformer ratio (HTR) Plasma Wakefield Accelerator (PWFA) based on shaped electron bunches is an important topic of plasma wakefield acceleration for future light sources and colliders [1]. To explore the possibility of implementing PWFA at SXFEL, we performed 3D PIC simulations using shaped electron beam parameters obtained by start-to-end beam line simulations [2]. The PIC simulations show that an average transformer ratio around 4 can be maintained for about 10 cm long low density plasma, and the energy gain of the trailing bunch eventually reaches 5.9 GeV. Simulations and analysis are also performed to check the effects of transverse beam size on HTR acceleration. In addition, plasma density downramp injection has also been tested as a possible high brightness injection method for HTR acceleration, and preliminary results will be presented.
[*] Lu W, An W, Huang C, et al. High Transformer ratio PWFA for Applications on XFELs. Bulletin of the American Physical Society, 2009, 54.
[**] Z. Wang, Z. T. Zhao, et al. private communication

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TUPIK026

Simulations of Positron Capture and Acceleration in the Linear Wakefield of Plasma

wakefield, positron, laser, emittance

1737

M.M. Peng, W. Gai
TUB, Beijing, People's Republic of China

We present the study of positrons capturing dynamics in the wakefield of plasma generated either by a laser or electron beam. Only simplified linear wakefield models were used as first order approximation. By analysing the phase space and beam dynamics, we show that phase space for capturing is rather small, only high brightness beam with very short pulse length can be captured with reasonable rate for wakefields of 1 - 10 GeV/m and wave-length of 100 micron.

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TUPIK031

Driver-Witness-Bunches for Plasma-Wakefield Acceleration at the MAX IV Linear Accelerator

electron, linac, wakefield, simulation

1743

J. Björklund Svensson, H.E. Ekerfelt, O. Lundh
Lund University, Lund, Sweden
J. Andersson, F. Curbis, M. Kotur, F. Lindau, E. Mansten, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photo-cathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.

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TUPIK032

AWAKE Proton Beam Commissioning

proton, laser, alignment, experiment

1747

J.S. Schmidt, D. Barrientos, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, T. Bohl, C. Bracco, S. Cettour Cave, H. Damerau, V. Fedosseev, F. Friebel, S.J. Gessner, A. Goldblatt, E. Gschwendtner, L.K. Jensen, V. Kain, T. Lefèvre, S. Mazzoni, J.C. Molendijk, A. Pardons, C. Pasquino, S.F. Rey, H. Vincke, U. Wehrle
CERN, Geneva, Switzerland
J.T. Moody
MPI-P, München, Germany
K. Rieger
MPI, Muenchen, Germany

AWAKE will be the first proton driven plasma wakefield acceleration experiment worldwide. The facility is located in the former CNGS area at CERN and will include a proton, laser and electron beam line merging in a 10 m long plasma cell, which is followed by the experimental diagnostics. In the first phase of the AWAKE physics program, which started at the end of 2016, the effect of the plasma on a high energy proton beam will be studied. A proton bunch is expected to experience the so called self-modulation instability, which leads to the creation of micro-bunches within the long proton bunch. The plasma channel is created in a rubidium vapor via field ionization by a TW laser pulse. This laser beam has to overlap with the proton beam over the full length of the plasma cell, resulting in tight requirements for the stability of the proton beam at the plasma cell in the order of ~ 0.1 mm. In this paper the beam commissioning results of the ~810 m long transfer line for proton bunches with 3·10¹¹ protons/bunch and a momentum of 400 GeV/c will be presented with a focus on the challenges of the parallel operation of the laser and proton beam.

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TUPVA087

ADIGE: The Radioactive Ion Beam Injector of the SPES Project

ion, ECR, rfq, extraction

2281

A. Galatà, L. Bellan, G. Bisoffi, M. Comunian, L. Martin, M.F. Moisio, A. Palmieri, A. Pisent, G.P. Prete, C. R. Roncolato
INFN/LNL, Legnaro (PD), Italy

The Selective Production of Exotic Species (SPES) project is presently under development at INFN-LNL: aim of this project is the production, ionization and post-acceleration of radioactive ions to perform forefront research in nuclear physics. An ECR-based charge breeder (SPES-CB) will allow post-acceleration of radioactive ions: in particular, the SPES-CB has been designed and developed by LPSC of Grenoble, based on the Phoenix booster. It will be equipped with a complete test bench totally integrated with the SPES beam line: this part of the post-accelerator, together with the newly designed RFQ, composes the so-called ADIGE injector for the superconducting linac ALPI. The injector will employ a unique Medium Resolution Mass Spectrometer (MRMS, R=1/1000), mounted downstream the SPES-CB, in order to avoid the typical drawback of the ECR-based charge breeding technique, that is the beam contamination. This contribution describes the ADIGE injector, with particular attention to the analysis of possible contaminations and the performances expected for the MRMS, showing the beam dynamics calculations for a reference radioactive beam.

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WEOBB2

Beam Commissioning of the High Intensity Proton Source Developed at INFN-LNS for the European Spallation Source

proton, emittance, ion, ion-source

2530

L. Neri, L. Allegra, A. Amato, G. Calabrese, A.C. Caruso, G. Castro, L. Celona, F. Chines, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, G. Manno, S. Marletta, D. Mascali, M. Mazzaglia, A. Miraglia, S. Passarello, G. Pastore, A. Seminara, A. Spartà, G. Torrisi, S. Vinciguerra
INFN/LNS, Catania, Italy

At the Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.

Slides WEOBB2 [2.457 MB]

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WEPAB123

A Phase Matching, Adiabatic Accelerator

electron, acceleration, laser, wakefield

2861

F. Lemery
University of Hamburg, Hamburg, Germany
K. Flöttmann
DESY, Hamburg, Germany
F.X. Kärtner
MIT, Cambridge, Massachusetts, USA
F.X. Kärtner
CFEL, Hamburg, Germany
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Tabletop accelerators are a thing of the future. Reducing their size will require scaling down electromagnetic wavelengths; however, without correspondingly high field gradients, particles will be more susceptible to phase-slippage – especially at low energy. We investigate how an adiabatically-tapered dielectric-lined waveguide could maintain phase-matching between the accelerating mode and electron bunch. We benchmark our simple model with CST and implement it into ASTRA; finally we provide a first glimpse into the beam dynamics in a phase-matching accelerator.

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WEPAB134

Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices

simulation, emittance, scattering, electron

2891

J.S. Ellison
IIT, Chicago, Illinois, USA
P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon-based accelerators. One of the crucial physics processes specific to muon accelerators that has not yet been simulated in detail is beam-induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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WEPAB137

Cold Muonium Negative Ion Production

ion, electron, target, collider

2898

V.G. Dudnikov, M.A. Cummings, R.P. Johnson
Muons, Inc, Illinois, USA
A.V. Dudnikov
BINP SB RAS, Novosibirsk, Russia

Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.

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WEPIK025

Spectral Diagnostics of Argon Plasma in a 10mm Aperture Plasma Window

electron, cathode, vacuum, ion

2978

P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, Z.X. Yuan, K. Zhu
PKU, Beijing, People's Republic of China

A 10 mm diameter 60 mm long plasma window has been designed and managed to generate arc discharge with argon gas experimentally in Peking University. Based on the previous experiments and simulations, we have measured the electron temperature and density of the plasma via argon spectral diagnostics, and analyzed the conditions to satisfy the criterion of local thermal equilibrium (L.T.E). The electron temperature is in the range of 12000 K to 16000 K. The electron density is in the range of 2.2×10¹⁶ cm^-3 to 3.2×10¹⁶ cm^-3, increasing with discharge current and gas flow rate. The results indicate that our argon plasma is in the L.T.E status. The sealing pressure characteristics of the plasma window is mentioned as well.

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WEPVA001

Electron Injector for Multi-Stage Laser-Driven Plasma Accelerators

electron, laser, simulation, acceleration

3244

B. Cros, T. Audet, P. Lee, G. Maynard
CNRS LPGP Univ Paris Sud, Orsay, France
A. Chancé, O. Delferrière, A. Mosnier
CEA/DSM/IRFU, France
N. Delerue
LAL, Orsay, France
S. Dobosz-Dufrénoy, A. Maitrallain, P. Monot
CEA, Gif-sur-Yvette, France
J. Schwindling
CEA/IRFU, Gif-sur-Yvette, France
A. Specka
LLR, Palaiseau, France

Funding: LAbex PALM, Labex P2IO, Triangle de la Physique, ANR grant Equipex CILEX APOLLON, EU H2020 research and innovation programme under grant agreement No. 653782 EUPRAXIA.
An electron injector in the 50-200 MeV range, based on laser wakefield acceleration, is studied in the context of multi-stage laser plasma acceleration. Test experiments carried out at the UHI100 laser facility show that electron bunches in the 100 MeV range, generated by ionization-induced injection mechanism, and accelerated by laser driven wakefield in a mm-scale length plasma can be transported using a magnetic line and precisely analysed. A comparison with simulation results provides insights on electron dynamics and indicates ways to optimize the injector.

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WEPVA012

Laser Proton Accelerator with Improved Repeatability at Peking University

laser, target, proton, acceleration

3275

Y.R. Shou
Peking University, School of Physics, Beijing, People's Republic of China
Y.X. Geng, C. Li, L.R.F. Li, Q. Liao, C. Lin, H.Y. Lu, W.J. Ma, P. Wang, M. Wu, X. Xu, X.Q. Yan, Y.Y. Zhao, J.G. Zhu
PKU, Beijing, People's Republic of China

Funding: National Basic Research Program of China (Grant No. 2013CBA01502), National Natural Science Foundation of China (Grants No. 11575011) and National Grand Instrument Project (2012YQ030142).
The repeatability of laser proton accelerator is mainly limited by laser plasma interaction, laser target coupling and laser parameter variation. In our recent experiments performed on the Compact Laser Plasma Accelerator at Peking University, gain of proton beams with improved repeatability is demonstrated. In order to control the laser plasma interaction in pre-plasma, cross polarized-wave (XPW) generation technique is employed to provide a laser pulse with a good contrast of 10^-10. A semi-automatic laser and target alignment system with a sensitivity of few micrometers is employed. The repetition rate of the laser proton accelerator is improved to the level of 0.1 Hz which is beneficial to decrease laser parameter variation. The shot-to-shot variation of proton energies is about 9% for a level of confidence of 0.95.

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WEPVA013

Small Size Neutron Generators with Laser Induced Plasma and Electron Conductivity Suppressed by Magnetic Field

laser, neutron, target, electron

3278

V.I. Rashchikov, S.M. Polozov, A.E. Shikanov
MEPhI, Moscow, Russia

Coaxial neutron tubes generators with transverse dimension less than 0.1 m are discussed. Laser plasma containing deuterons is created at the anode by a focused laser beam. Deuterons from plasma are accelerated by pulse voltage and produces neutrons on cylindrical cathode symmetrically surrounding the anode. Magnetic field was used to suppress knock on parasitic electron current in the accelerating gap. Computer simulation with code SUMA* was fulfilled to investigate output neutron flow dependence on laser produced plasma density, magnetic fields and pulse voltage shapes and amplitudes, cathode and anode materials. The results obtained are in a good agreement with conducted experiments on diode with electron conductivity suppressed by magnetic field produced by permanent magnets**.
*V.I.Rashchikov, Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 10(18), 50 (1990).
**A.E.Shikanov et al., Atomic energy, 119, No.4, 258 (2016).

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WEPVA017

Efficiency Enhancement Induced by a Precursor Electron Bunch in Quasi-Phase Matched Direct Laser Acceleration

electron, ion, focusing, laser

3289

C.-Y. Hsieh, S.-H. Chen
NCU, Chung Li, Taiwan
I. Jovanovic
NERS-UM, Ann Arbor, Michigan, USA
M.W. Lin
National Tsing-Hua University (NTHU), Hsinchu, Taiwan

Funding: This work is supported by the Ministry of Science and Technology in Taiwan by Grant MOST 104-2112-M-008-013-MY3 and the United States Defense Threat Reduction Agency through contract HDTRA1-11-1-0009
Direct laser acceleration (DLA) of an electron bunch can be achieved by utilizing the axial field of a well-guided, radially polarized laser pulse in a density-modulated plasma waveguide*. However, the ponderomotive force of a TW-class laser pulse excites a plasma wave that can generate a defocusing electrostatic field, which significantly deteriorates the transverse properties of the injected electron witness bunch**. To improve the quality of the accelerated witness bunch, an additional leading electron bunch, termed as a precursor, is introduced to generate ion-focusing force to effectively confine the trailing witness bunch. We conducted three-dimensional particle-in-cell simulations to investigate the effect of bunch charge, transverse size of the precursor, and the axial separation between the precursor and the witness bunch on the efficacy of DLA. Results indicate that the transverse properties of the witness bunch can be maintained and the overall DLA efficiency can be improved, when a favorable ion-focusing force is provided by the precursor.
* A. G. York, et al., Phys. Rev. Lett. 100, 195001 (2008).
** M. -W. Lin et al., Phys. Plasmas 21, 093109 (2014).

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WEPVA058

Development of HOM Absorber for SuperKEKB

electron, HOM, vacuum, photon

3394

S. Terui, T. Ishibashi, Y. Suetsugu, Y. Takeuchi, K. Watanabe
KEK, Ibaraki, Japan
H. Ishizaki, A. Kimura, T. Sawhata
Metal Technology Co. Ltd., Ibaraki, Japan

Higher-order modes (HOM) absorbers are necessary components for recent high-power accelerators in order to prevent beam instabilities (e.g. HOM- Beam Break Up instabilities) or the overheating of vacuum components. Several kinds of absorber materials, such as SiC, ferrite and Kanthal, have been investigated and applied in accelerators. Among these materials, ferrite has been found to be superior to others because of its higher HOM absorbing efficiency. However, because of its low tensile strength and small thermal expansion rate, it cannot be easily bonded to other metals thus limiting its use as a HOM absorber. We reported the success of the fabrication of ferrite-copper-blocks using the spark plasma sintering (SPS)-technique last year. This year we report testing with a high-power RF source and measuring gas desorption rate after baking and secondary electron yield.

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WEPVA141

Ion Cyclotron Resonance Heating Transmitter Opening Switch Upgrade

operation, high-voltage, impedance, resonance

3600

M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Diversified Technologies Inc. (DTI) has installed a high-power solid-state opening switch upgrade package to replace the mercury ignitron crowbars in the Ion Cyclotron Resonance Heating (ICRH) Transmitters at MIT Plasma Fusion Science Center's (PFSC) Alcator C Mod, a Tokamak-type fusion experimental device. The speed of the series opening switch avoids the large fault currents on the transformer and power feed inherent with a crowbar. This improvement enables re-optimization of the Transformer/Rectifier (T/R) set, ultimately allowing increased power output and increased tetrode reliability. The ratings of the prior high voltage power supply are a compromise between high output power (lower impedance required from the T/R set) and crowbar reliability (higher impedance required from the power supply to limit fault current). DTI's opening switch upgrade safely allows the use of significantly reduced transformer impedance and lower droop, giving increased power as well as improved tube protection. DTI's opening switch kit can readily be adapted to any similar transmitters as an upgrade from a crowbar.

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THPAB013

A Fast Particle Tracking Tool for the Simulation of Dielectric Laser Accelerators

simulation, laser, GPU, space-charge

3716

F. Mayet, R.W. Aßmann, U. Dorda, W. Kuropka
DESY, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Funding: GBMF - Gordon and Betty Moore Foundation
In order to simulate the beam dynamics in grating based Dielectric Laser Accelerators (DLA) fully self-consistent PIC codes are usually employed. These codes model the evolution of both the electromagnetic fields inside a laser-driven DLA and the beam phase space very accurately. The main drawback of these codes is that they are computationally very expensive. While the simulation of a single DLA period is feasible with these codes, long multi-period structures cannot be studied without access to HPC clusters. We present a fast particle tracking tool for the simulation of long DLA structures. DLATracker is a parallelized code based on the analytical reconstruction of the in-channel electromagnetic fields and a Boris/Vay-type particle pusher. It computational kernel is written in OpenCL and can run on both CPUs and GPUs. The main code is following a modular approach and is written in Python 2.7. This way the code can be easiliy extended for different use cases. In order to benchmark the code, simulation results are compared to results obtained with the PIC code VSim 7.2.

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THPAB050

Simulations of Beam-Beam Interactions With RF-Track for the AWAKE Primary Beam Lines

electron, proton, simulation, space-charge

3823

J.S. Schmidt, A. Latina
CERN, Geneva, Switzerland

The AWAKE project at CERN will use a high-energy proton beam at 400 GeV/c to drive wake'elds in a plasma. The amplitude of these wake'elds will be probed by injecting into the plasma a low-energy electron beam (10-20 MeV/c), which will be accelerated to several GeV. Upstream of the plasma cell the two beams will either be transported coaxially or with an o'set of few millimetres for about 6 m. The interaction between the two beams in this beam line has been investigated in the past, with a dedicated simulation code tracking particles under the in'uence of direct space-charge e'ects. These simulations have recently been crosschecked with a new simulation code called RF-Track, developed at CERN to simulate low energy accelerators. RF-Track can track multiple-specie beams at arbitrary energies, taking into account the full electromagnetic particle-to-particle inter-action. For its characteristics RF-Track seems an ideal tool to study the AWAKE two-beam interaction. The results of these studies are presented in this paper and compared to the previous results. The implications for the facility performance are discussed.

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THPAB093

Synchronization of a Photo-Injector and a High Power Laser With Independent Clocks

laser, electron, gun, feedback

3935

N. Delerue, C. Bruni, K. Cassou, V. Chaumat, R. Chiche, D. Douillet, N. ElKamchi, S. Jenzer, V. Kubytskyi, P. Lepercq, H. Purwar, H. Roesch
LAL, Orsay, France
E. Baynard, M. Pittman
CLUPS, Orsay, France
J. Demailly, O. Guilbaud, S. Kazamias, G. Maynard, O. Neveu, D. Ros
CNRS LPGP Univ Paris Sud, Orsay, France
D. Garzella
CEA, Gif-sur-Yvette, France
R. Prazeres
LCP/CLIO, Orsay, Cedex, France

Funding: LAL/IN2P3/CNRS and Université Paris-Sud
The plasma acceleration project ESCULAP (ElectronS CoUrts pour L'Acc\'el\'eration Plasma) aims at studying electrons injection into a laser plasma accelerator. This requires the injection of short electron bunches generated by the photo injector PHIL (Photo injector at LAL) into a plasma wave by the high power femtosecond Laser LASERIX. As a first step we have studied how to synchronize PHIL and LASERIX. As these two machines had not been initially designed to work together, simple synchronization solutions were not available. We detail here the synchronisation scheme that we have tested and the experimental results obtained.

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THPIK022

Measurements of High-Order Magnetic Field Components of Permanent Quadrupole Magnets for a Laser-Plasma-Driven Undulator X-Ray Source

quadrupole, electron, laser, permanent-magnet

4145

P. Winkler
University of Hamburg, Hamburg, Germany
D. Kocon, A.Y. Molodozhentsev
ELI-BEAMS, Prague, Czech Republic
A.R. Maier
CFEL, Hamburg, Germany
L. Pribyl
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
M. Trunk
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Laser wakefield acceleration as a novel source of high-energy electron beam is a prominent candidate to drive a next generation of compact light sources. For applications, the electron beam needs to be captured using quadrupole magnets with extremely high field gradient. It allows to preserve properties of the laser-plasma driven electron beam. We designed and manufactured compact permanent quadrupole magnets providing magnetic field gradient up to 510 T/m at an aperture radius of only of a few mm. The Halbach-type quadrupole magents use 12 NdFeB wedges with a remanent magnetic field of 1.2 Tesla. We measured the magnetic field of the permanent magnet quadrupoles using the pulsed-wire and rotating-coil methods. Here, we present an analysis of the magnetic field quality and, in particular, the integrated field gradient and high-order field components. We further discuss the influence of the field imperfections on the electron beam quality and its consequences for application in the transport line of a laser-plasma-driven undulator X-ray source.

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THPVA005

Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens

electron, simulation, experiment, space-charge

4421

C. Beberweil, M. Droba, S. Klaproth, O. Meusel, D. Noll, H. Podlech, K. Schulte, K.I. Thoma
IAP, Frankfurt am Main, Germany
S. Gammino, D. Mascali
INFN/LNS, Catania, Italy
L. Malferrari, A. Montanari, F. Odorici
INFN-Bologna, Bologna, Italy

Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma*. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender** was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented.
* Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012
** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015

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THPVA007

Matching Space-charge Dominated Electron Bunches into the Plasma Accelerator at SINBAD

emittance, electron, simulation, focusing

4429

J. Zhu, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for Laser Wake-Field Acceleration (LWFA) experiments. In order to avoid emittance growth in plasma cells with ultra-high accelerating gradients the injection and transport of electron bunches with beta functions of mm-size or even smaller are required. This kind of bunch is usually space-charged dominated since the energy is low (< 200 MeV) while the peak current is high for allowing the electron bunches to be used for Free Electron-Laser (FEL) generation. We present the beamline design and explore the possible beam parameters at the SINBAD linac by start-to-end simulations.

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