IPAC2017 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
MOZB1	First Results with the Novel Peta-Watt Laser Acceleration Facility in Dresden	laser, target, plasma, electron	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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MOPAB075	Measurement of Electron Bunch Length via a Tunable-Gap Undulator	radiation, electron, undulator, laser	295
	X.L. Su, Y.-C. Du, W.-H. Huang, L. Niu, C.-X. Tang, Q.L. Tian, D. Wang, L.X. Yan TUB, Beijing, People's Republic of China Y.F. Liang Tsinghua University, Beijing, People's Republic of China
	A THz undulator with widely tunable gap is constructed and installed at Tsinghua University beamline, which is applied for narrow-band THz radiation and measurements of electron bunch longitudinal structure. This is a planar electromagnetic device with 8 regular periods, each 10 cm long. The field range B=0.15- 0.99 T peak field on axis while changing the gap from 75mm to 23mm. In the experiments, we scanned the undulator gap to measure the radiation intensity at different resonant frequency, thus we can get the bunch length even form factor of the bunch. The demonstrated experimental results show that the bunch of 220pC compressed by chicane in Tsinghua beamline is about 120fs (rms), which agree well with the simulations. The resolution of bunch length measurement with this method can be attoseconds by optimized undulator. Furthermore, the form factor of electron bunch train can also be measured.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB075
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MOPIK004	Demonstration of an All-Optically Driven Sub-keV THz Gun	electron, gun, laser, operation	503
	W.R. Huang, K.-H. Hong, F.X. Kärtner, E.A. Nanni, KR. Ravi MIT, Cambridge, Massachusetts, USA A-L. Calendron, H. Cankaya, A. Fallahi, F.X. Kärtner, X. Wu CFEL, Hamburg, Germany D. Zhang DESY, Hamburg, Germany
	Funding: European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920 Intense ultrashort THz and optical pulses with single-cycle pulse duration became possible after the recent advances in ultrafast technologies. Using such ultrashort pulses for electron acceleration offers advantages in terms of higher thresholds for material breakdown which opens up a promising path towards increased acceleration gradients. In addition, using optically generated THz pulses enable inherently synchronized acceleration schemes, since accelerating field and particle injecting field are excited by a single seed laser. In this contribution, we present the first experimental demonstration of laser-driven THz acceleration of electrons initially at rest. It is shown that strong-field, single-cycle THz fields accelerate electrons with peak energies of up to 0.8 keV in an ultracompact THz gun with bunch charge of 40 fC. The achieved energy spreads are as low as 5.8%.
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MOPIK005	Compact Electron Injectors Using Laser Driven THz Cavities	cavity, electron, gun, laser	506
	M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis, A. Yahaghi CFEL, Hamburg, Germany R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, G. Vashchenko, T. Vinatier, D. Zhang, C. Zhou DESY, Hamburg, Germany
	We present ultra-small electron injectors based on cascaded cavities excited by short multi-cycle THz signals. The designed structure is a 3.5 cell normal conducting cavity operating at 300 GHz. This cavity is able to generate pC electron bunches and accelerate them up to 250 keV using less than 1 mJ THz energy. Unlike conventional RF guns, the designed cavity operates in a transient state which, in combination with the high frequency of the driving field, makes it possible to apply accelerating gradients as high as 500 MV/m. Such high accelerating gradients are promising for the generation of high brightness electron beams with transverse emittances in the nm-rad range. The designed cavity can be used as the injector for a compact accelerator of low charge bunches.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK005
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MOPIK007	THz Driven Electron Acceleration with a Multilayer Structure	electron, laser, gun, dipole	512
	D. Zhang, M. Fakhari, W. Qiao, C. Zhou DESY, Hamburg, Germany F. Ahr, A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, F.X. Kärtner, F. Lemery, N.H. Matlis, X. Wu CFEL, Hamburg, Germany W.R. Huang, F.X. Kärtner MIT, Cambridge, Massachusetts, USA C. Zhou University of Hamburg, Hamburg, Germany
	We present first results in THz-based electron acceleration using a novel multilayer structure which we dub a Butterfly LINAC. THz-based accelerators are mm-scale devices that bridge the gap between micron-scale, ultra-compact devices such as laser-plasma accelerators (LPAs) and dielectric laser accelerators (DLAs) and meter-scale conventional accelerators. These intermediate-scale devices are promising because they combine many of the benefits of LPAs and DLAs, such as intrinsic synchronization and high acceleration gradients with the benefits of conventional accelerators such as high charge capacity, tunability as well as the robustness, stability and simple fabrication of static, macroscopic acceleration structures. The Butterfly LINAC allows optimization of electron acceleration using transversely-coupled single-cycle THz pulses by phase-matching electrons with the driving field. Proof-of-concept experiments will be described demonstrating 10 keV energy gain of a 55 keV source, in good agreement with simulation. Scalability of this device to the MeV level and applicability towards free electron lasers and ultrafast electron diffractometers will also be discussed.
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MOPIK017	Simultaneous Generation of Drive and Witness Beam for Collinear Wakefield Acceleration	wakefield, emittance, controls, quadrupole	535
	G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, J.G. Power ANL, Argonne, Illinois, USA
	Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357. Generating the drive and witness bunch for collinear wakefield acceleration (CWFA) requires precise control of the longitudinal bunch shape for each bunch as well as the controlling their separation. The emittance exchange (EEX) beamline and a transverse mask can be used to achieve all of these requirements. First, this EEX-based method can independently control the longitudinal bunch shape of each bunches so that the drive bunch is shaped to generate a high transformer ratio while witness bunch is shaped to suppress its energy spread. Second, the timing jitter between the drive and witness bunch poses a serious limitation to the CWFA scheme but the EEX-based method eliminates this since both bunches are generated at the same time and share the exactly same beamline so there are no relative errors. In this paper, we confirm the feasibility of this EEX-based method for simultaneous generation with simulation for CWFA in a dielectric structure.
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MOPIK018	Micro-Scale Electron Beam Generation Using Pyroelectric Crystals	electron, laser, injection, diagnostics	538
	R.B. Yoder, Z. Kabilova Goucher College, Baltimore, Maryland, USA
	Novel laser-powered acceleration structures currently under development, which have dimensions comparable to optical wavelengths and can be constructed on a silicon wafer, require injection of a sub-micron-scale electron bunch to achieve high-quality, monoenergetic output beams. A potential injection mechanism for such micro-scale beams relies on field emission from a nanotip array, followed by acceleration to near-relativistic energies. We demonstrate field emission of electrons from a lithium niobate crystal during heating and cooling, and describe the production of electrons within a hollow channel along the axis of a lithium niobate crystal. Measurements of emitted beam properties are compared with direct measurements of crystal fields under comparable conditions and modeled mathematically.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK018
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MOPIK021	Generation of Transversely Segmented Beam Using a Nano-Patterned Photocathode	cathode, laser, simulation, gun	545
	A. Lueangaramwong, P. Piot Northern Illinois University, DeKalb, Illinois, USA G. Andonian RadiaBeam, Santa Monica, California, USA P. Piot Fermilab, Batavia, Illinois, USA
	Funding: Work supported by US Department of Energy (DOE) contract DE-SC0009656 with Radiabeam Technologies and by NSF grant PHY-1535401 with Northern Illinois University. Plasmonic photocathodes – nano-patterned photocathodes with periodicity comparable to the excitation laser – have demonstrated enhanced quantum efficiency. In the present paper we present numerical simulations of the beam dynamics associated to the emission process from this type of cathodes and to the subsequent acceleration to relativistic energies by combining WARP and IMPACT-T programs. We especially consider the possibility to transversely image the cathode surface at high energy and enable the generation of transversely segment beams.
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MOPIK068	Beam Dynamics Design Parameters for KONUS Lattices	lattice, linac, cavity, emittance	683
	R. Tiede, H. Hähnel, U. Ratzinger IAP, Frankfurt am Main, Germany
	The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept has been successfully applied on several linacs, some of them in routine operation since decades. However, the KONUS lattice parameters optimization is often done in a results-oriented approach, depending on the designers' experience. This paper focuses on the description of the longitudinal beam motion along one KONUS lattice period. A test lattice is used for demonstrating the potential of KONUS lattices with respect to stable, periodic beam motion with emittance growth rates similar to those of conventional designs. The main objective of this ongoing work is to derive more general rules for the parametrization of KONUS lattices.
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MOPIK115	A Design for 10 GeV, High Peak-Current, Tightly Focused Electron Beams at FACET-II	emittance, linac, electron, simulation	807
	G.R. White SLAC, Menlo Park, California, USA
	Funding: This work was sponsored by the Department of Energy under Contract Number: DE-AC02-76SF00515 FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The design consists of a 135-MeV high-brightness photo-injector constructed in an off-axis injection line in Sector 10 of the SLAC Linac, two new 4-bend chicane bunch compressors installed in Sectors 11 and 14, with a third compression stage provided by the existing FACET W Chicane in Sector 20. We develop a design to deliver peak currents more than 160 kA to the Sector 20 interaction region at 10 GeV, with 10 'm-rad emittances at 2 nC bunch charge and 1.4 % rms energy spread. The Sector 20 bunch compressor is re-designed for maximum peak current throughput and minimal emittance degradation via CSR, and the FACET-II compression scheme is optimized. We present 6D start-end beam tracking simulations using Lucretia including ISR, CSR, wakefields and space charge effects.
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MOPIK117	On the Computation of Phase and Energy Gain for a Thin-Lens RF Gap Using a General Field Profile	simulation, linac, factory, cavity	810
	C.K. Allen ORNL, Oak Ridge, Tennessee, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC05-00OR22725. The thin-lens representation for an RF accelerating gap has been well developed and is documented by Lapostolle [5], Weiss [6], Wangler [14], and others [9], [10]. These models assume that the axial electric field is both centered and symmetric so it has a cosine expansion. Presented here is a model that considers general axial fields. Both the cosine and sine transit time factors are required plus their Hilbert transforms. The combination yields a complex Hamiltonian rotating in the complex plane with the synchronous phase. The phase and energy gains are computed in the pre-gap and post-gap regions then aligned with asymptotic values of wave number. Derivations are outlined, examples are shown, and simulations presented.
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MOPVA012	The Dedicated Accelerator R&D Facility Sinbad at DESY	linac, electron, laser, experiment	869
	U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu DESY, Hamburg, Germany A. Fallahi, F.X. Kärtner, N.H. Matlis CFEL, Hamburg, Germany
	We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.
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MOPVA013	Application of Non-Isochronous Beam Dynamics in ERLs for Improving Energy Spread and Beam Stability	linac, electron, operation, recirculation	873
	F. Hug IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a non-isochronous recirculation scheme the recirculation paths provide a non-zero longitudinal dispersion while the accelerating field is operated at a certain phase off-crest with respect to the maximum. In few turn linacs like ERLs and in microtrons non-isochronous beam dynamics can be used to reduce the energy spread by cancelling out any rf-jitters coming from the linac cavities. To do so the longitudinal phase advance needs to be tuned to a half-integer number of oscillations in longitudinal phase space. Then the total energy spread after main linac acceleration conserves the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. Such concept provides an inherent beam stability and has been introduced many years ago [] and proven to work successfully in a few-turn recirculator already []. We will present beam dynamics calculations for the application of nonisochronous beam dynamics in single- and multi-turn energy recovery linacs at different longitudinal working points. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA014	Injector Linac Stability Requirements for High Precision Experiments at MESA	experiment, linac, electron, operation	876
	F. Hug, R.G. Heine IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [,]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA145	Improvements on CNAO Accelerator for Ocular Treatments	extraction, proton, injection, synchrotron	1194
	L. Falbo, E. Bressi, C. Priano CNAO Foundation, Milan, Italy
	Ocular melanoma has been successfully treated worldwide since many years using proton beams. CNAO is the only Italian hadrontherapy facility able to treat tumours with both proton and carbon ion high-energy scanning beams accelerated by a synchrotron; the machine was commissioned in 2011 and more than 1000 patients have been treated so far. With respect to the othercases, , ocular melanoma treatment needed important changes both under the medical physics and machine physics points of view. The main goal of this work is to describe the changes in the machine set up to increase the proton current by a factor of 5, this task representing a sort of recommissioning of the synchrotron.
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MOPVA146	Optimization of Carbon Treatments at CNAO	dipole, extraction, feedback, ion	1197
	L. Falbo, E. Bressi, C. Priano CNAO Foundation, Milan, Italy
	CNAO facility is treating patients with carbon ion beams since 2012. Often carbon ions are used to treat tumors with great volumes that causes long time irradiations: this represents a complaint for the patient, a limit in the number of treatable patients per day and an increase in the cost of the treatment itself. An effort has been done in the last year to increase the particle intensity in order to reduce the irradiation time for the carbon treatments: this article illustrates the changes in the machine done to achieve this goal.
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TUOBB3	HORIZON 2020 EuPRAXIA Design Study	plasma, laser, electron, 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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TUZB1	Final Results From the Clic Test Facility (CTF3)	linac, operation, emittance, beam-loading	1269
	R. Corsini CERN, Geneva, Switzerland
	The unique CLIC TEST Facility (CTF3) has been built more than a decade ago to demonstrate the feasibility of the CLIC two beam acceleration scheme. The emphasis was one the high current drive beam generation using a fully loaded highly efficient linac and a complex combination scheme to increase beam current and bunch repetition frequency. This drive beam has been used for deceleration experiments and two beam acceleration. A wealth of relevant results for accelerator physics even beyond CLIC has been obtained and will be presented. The rf to beam efficiency of the linac exceeds 95%, after combination the 28 A drive beam with 12 GHz bunch repetition rate has been used to extract more than 50% of its energy producing 1.3 GW of 12 GHz power as well as performing two beam acceleration at 12 GHz with gradients up to 150 MV/m.
	Slides TUZB1 [23.702 MB]
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TUOCB3	CBETA - Cornell University Brookhaven National Laboratory Electron Energy Recovery Test Accelerator	electron, linac, permanent-magnet, gun	1285
	D. Trbojevic, S. Bellavia, J.S. Berg, M. Blaskiewicz, S.J. Brooks, K.A. Brown, W. Fischer, F.X. Karl, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte BNL, Upton, Long Island, New York, USA N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, B.M. Dunham, R.G. Eichhorn, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, B.K. Heltsley, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Douglas JLab, Newport News, Virginia, USA D. Jusic, J.R. Patterson Cornell University, Ithaca, New York, USA
	Funding: New York State Energy Research and Development Authority (NYSERDA) Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first SRF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the the linac to form an Electron Energy Recovery (ERL) system. Electron beam from the 6 MeV injector is injected into the 36 MeV superconducting linac, and accelerated by four successive passes: from 42 MeV up to 150 MeV using the same NS-FFAG structure made of permanent magnets. After the maximum energy of 150 MeV is reached, the electron beam is brought back to the linac with opposite Radio Frequency (RF) phase. Energy is recovered and reduced to the initial value of 6 MeV with 4 additional passes. There are many novelties: a single NS-FFAG structure, made of permanent magnets, brings electrons with four different energies back to the linac. A new adiabatic NS-FFAG arc-to-straight section merges 4 separated orbits into a single orbit in the straight section.
	Slides TUOCB3 [41.888 MB]
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TUPAB038	Electron Acceleration With a Ultrafast Gun Driven by Single-Cycle Terahertz Pulses	electron, gun, timing, laser	1406
	C. Zhou, F. Ahr, A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis, W. Qiao, X. Wu, D. Zhang CFEL, Hamburg, Germany R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, G. Vashchenko, T. Vinatier DESY, Hamburg, Germany
	Funding: This work was supported by the European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920. We present results on an improved THz-driven electron gun using transversely-incident single-cycle THz pulses using a horn-coupler. Intrinsic synchronization between the electrons and the driving field was achieved by using a single laser system to create electrons by UV photoemission and to create THz radiation by difference frequency generation in a tilted-pulse front geometry. Details of the optical setups for the UV and THz pulses will be described as well as preliminary results showing evidence of electron acceleration.
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TUPAB040	Status Update of the SINBAD-ARES Linac Under Construction at DESY	linac, electron, diagnostics, laser	1412
	B. Marchetti, R.W. Aßmann, S. Baark, U. Dorda, C. Engling, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, M. Körfer, B. Krause, G. Kube, J. Kuhlmann, S. Lederer, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, A. Petrov, S. Pfeiffer, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, S. Vilcins, M. Werner, Ch. Wiebers, L. Winkelmann, K. Wittenburg, J. Zhu DESY, Hamburg, Germany
	ARES (Accelerator Research Experiment at Sinbad) is a linear accelerator for the production of low charge (from few pC to sub-pC) electron bunches with 100 MeV energy, fs and sub-fs duration and excellent arrival time stability. This experiment is currently under construction at DESY Hamburg and it is foreseen to start operation by the beginning of 2018 with the commissioning of the RF-gun. After an initial beam characterization phase, ARES will provide high temporal resolution probes for testing novel acceleration techniques, such as Laser driven plasma Wake-Field Acceleration (LWFA), Dielectric Laser Acceleration (DLA) and THz driven acceleration. In this work we present an overview of the present design of the linac with a special focus on 3D integration and planned installation phases of the beamline.
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TUPIK009	External Injection Into a Laser-Driven Plasma Accelerator With Sub-Femtosecond Timing Jitter	plasma, laser, electron, injection	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	plasma, laser, electron, wakefield	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	plasma, laser, electron, emittance	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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TUPIK018	Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ	plasma, wakefield, 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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TUPIK022	Innovative Single-Shot Diagnostics for Electrons From Laser Wakefield Acceleration at FLAME	laser, electron, target, emittance	1727
	F.G. Bisesto, M.P. Anania, E. Chiadroni, A. Curcio, M. Ferrario, R. Pompili INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy A. Zigler The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
	Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of electrons to GeV energy in few centimeters. Here we present all the plasma related activities currently underway at SPARC_LAB exploiting the high power laser FLAME. In particular, we will give an overview of the single shot diagnostics employed: Electro Optic Sampling (EOS) for temporal measurement and optical transition radiation (OTR) for an innovative one shot emittance measurements. In detail, the EOS technique has been employed to measure for the first time the longitudinal profile of electric field of fast electrons escaping from a solid target, driving the ions and protons acceleration, and to study the impact of using different target shapes. Moreover, a novel scheme for one shot emittance measurements based on OTR, developed and tested at SPARC_LAB LINAC, used in an experiment on electrons from laser wakefield acceleration still undergoing, will be shown.
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TUPIK023	Gas-filled Capillaries for Plasma-Based Accelerators	plasma, 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	plasma, simulation, injection, 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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TUPVA061	Beam Dynamics Study for the HIM&GSI Heavy Ion SC CW-LINAC	cavity, linac, ion, simulation	2217
	S. Yaramyshev, W.A. Barth, M. Heilmann GSI, Darmstadt, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia M. Basten, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	A sc cw-linac with variable output energy from 3.7 to 7.5 MeV/u for ions with mass to charge ratio of A/Z<6 is recently under development at HIM and GSI. Following the results of the latest RF-tests with the newly constructed sc CH-DTL cavity, even heavier ions up to Uranium 28+ could be potentially accelerated with the already reached higher RF-voltage. Also the possibility for an up to 10 MeV/u increased output energy, using the same 13 independent cavities, is under consideration. All these options require an advanced beam dynamics layout, as well as a versatile procedure for transverse and longitudinal beam matching along the entire linac. The proposed algorithms are discussed and the obtained simulation results are presented.
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TUPVA088	Observing Suppression of Syncrotron Oscillation Amplitudes	synchrotron, betatron, dipole, cavity	2284
	K. Jimbo Kyoto University, Kyoto, Japan
	We proposed a method to reduce loosing particles in acceleration stage of synchrotrons. A slowly varying horizontal electrostatic field may be useful to de-excite synchrotron oscillations. Then we have to somehow observe the damping of amplitudes of synchrotron oscillations to confirm the effect. We assume that the synchrotron component of rationalized Hamiltonian in acceleration stage is kept constant. Our experimental results did not contradict with this assumption. Taking advantage of this assumption, we can easily confirm the damping of synchrotron oscillation amplitudes experimentally through the increase of synchrotron frequencies. jimbo@iae.kyoto-u.ac.jp
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TUPVA092	An Upgrade Scenario of RF System to Achieve 1.6 MW Beam Acceleration in J-PARC RCS	cavity, power-supply, resonance, impedance	2297
	M. Yamamoto, M. Nomura, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	The J-PARC RCS has successfully accelerated 1 MW equivalent proton beam. However, the beam commissioning results and the particle tracking simulation suggest that the RCS has possibility to accelerate up to 1.6 MW beam. Since the power supply of the rf system almost reaches the limit under the condition of 1 MW beam, we consider the possible upgrade scenario of the rf system to accelerate 1.6 MW beam.
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TUPVA097	First Trial of the Muon Acceleration for J-Parc Muon g-2/edm Experiment	rfq, linac, diagnostics, target	2311
	R. Kitamura University of Tokyo, Tokyo, Japan S. Bae, B. Kim SNU, Seoul, Republic of Korea Y. Fukao, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura KEK, Tsukuba, Japan K. Hasegawa, Y. Kondo JAEA/J-PARC, Tokai-mura, Japan H. Iinuma Ibaraki University, Hitachi, Ibaraki, Japan K. Ishida RIKEN Nishina Center, Wako, Japan G.P. Razuvaev BINP SB RAS, Novosibirsk, Russia N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number 16H03987 and 16J07784. J-PARC E34 experiment aims to measure the muon g-2 and EDM precisely with the unique approach. The muon acceleration is the one of the most critical technique to achieve the goal of the sensitivity. The world's first muon LINAC is planed toward the muon acceleration to 212 MeV in J-PARC. The first trial of the muon acceleration is planed in the early 2017 with the J-PARC prototype RFQ ahead of the construction of the actual muon LINAC. The slow muon source is required for the RFQ test, since the input energy of the RFQ is 5.6 keV. The slow muon produced by the deceleration using the thin aluminum foil was observed. The demonstration of the muon extraction with 7 keV by the electrostatic accelerator called SOA lens was also done. The low-energy muon beam profile monitor (muon BPM) for the measurement of the beam intensity and profile in order to estimate the beam emittance was tested using the surface muon beam. The simulation for the beam emittance measurement has been developed. In this paper, the latest preparation status for the RFQ and the prospects for the muon acceleration test in J-PARC will be presented.
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TUPVA100	High Power Conditioning and First Beam Acceleration of the CSNS DTL-1	DTL, cavity, vacuum, linac	2320
	Y. Wang, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu CSNS, Guangdong Province, People's Republic of China Q. Chen, M.X. Fan, K.Y. Gong, H.C. Liu IHEP, Beijing, People's Republic of China
	The CSNS DTLs are divided into 4 cavities. The DTL-1 was transferred and installed in the CSNS Linac tunnel in August of 2015. The RF high power conditioning of DTL-1 started in December 2015 and ended in February 2016. At the end, we finished DTL-1 high power conditioning mission with peak power 1.5MW (1.1 times design value), 1.625% duty factor (650us, 25Hz). And the first beam has been successfully accelerated to the design value 21.6MeV with nearly 100% transmission efficiency. In this paper, the details of conditioning process were presented and one severe RF discharge breakdown was described specifically, which occurred during high power conditioning.
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TUPVA112	Acceleration of Polarized Proton and Deuteron Beams in Nuclotron at JINR	resonance, proton, polarization, betatron	2349
	Y. Filatov, A.V. Butenko, A.D. Kovalenko, V.A. Mikhaylov JINR, Dubna, Moscow Region, Russia Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	The superconducting synchrotron Nuclotron allows one to accelerate proton and deuteron beams up to 13.5 GeV/c. The beam depolarization occurs at the crossing of spin resonances. For deuterons, the vertical polarization is preserved almost to the maximum momentum. Tens of spin resonances are crossing during the proton acceleration. The proton polarization will be preserved by a solenoidal 5% snake up to 3.4 GeV/c at the field ramp rate of 1 T/s. It is planned to use a partial 50% snake to eliminate the resonant depolarization of the proton beam in the total momentum range of the accelerator. The results of simulations and experimental data are presented.
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TUPVA113	The Feature of Magnetic Field Formation of Multi-Purpose Isochronous Cyclotron DC280	cyclotron, ion, extraction, ion-source	2352
	I.A. Ivanenko, B. Gikal, G.G. Gulbekyan JINR, Dubna, Moscow Region, Russia V.P. Kukhtin, E.A. Lamzin, S.E. Sytchevsky NIIEFA, St. Petersburg, Russia
	At the present time the activities on creation of the new heavy-ion isochronous cyclotron DC280 are carried out at Joint Institute for Nuclear Research. The isochronous cyclotron DC-280 will produce accelerated beam of ions A/Z= 4 - 7 with a smooth variation of the beam energy W= 4 ' 8 MeV/n. The variation of energy is provided by the wide range of the magnetic field levels from 0.64T till 1.32T and usage of the 11 radial and 4 pairs of harmonic correcting coils. In the work the results of calculations and final measurements of the magnetic field are presented. The magnetic field of cyclotron DC-280 is formed in a good conformity with results of computer modeling.
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WEYB1	Towards a Fully Integrated Accelerator on a Chip: Dielectric Laser Acceleration (DLA) From the Source to Relativistic Electrons	laser, electron, emittance, simulation	2520
	K.P. Wootton, R.J. England, S.G. Tantawi SLAC, Menlo Park, California, USA R.W. Aßmann, I. Hartl, W. Kuropka, F. Mayet, A. Rühl DESY, Hamburg, Germany D.S. Black, R.L. Byer, H. Deng, S. Fan, J.S. Harris, T.W. Hughes, N. Sapra, O. Solgaard, J. Vuckovic Stanford University, Stanford, California, USA B.M. Cowan Tech-X, Boulder, Colorado, USA T. Egenolf, U. Niedermayer TEMF, TU Darmstadt, Darmstadt, Germany P. Hommelhoff, A. Li, N. Schönenberger University of Erlangen-Nuremberg, Erlangen, Germany J. Illmer, J.C. McNeur, A.K. Mittelbach, A.D. Tafel Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany R. Ischebeck, L. Rivkin PSI, Villigen PSI, Switzerland F.X. Kärtner MIT, Cambridge, Massachusetts, USA F.X. Kärtner CFEL, Hamburg, Germany W. Kuropka, F. Mayet University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany Y.J. Lee, M. Qi Purdue University, West Lafayette, Indiana, USA P. Musumeci UCLA, Los Angeles, California, USA L. Rivkin EPFL, Lausanne, Switzerland
	Funding: This work was supported by the U.S. Department of Energy, Office of Science, under Contract no. DE-AC02-76SF00515, and by the Gordon and Betty Moore Foundation under grant GBMF4744 (Accelerator on a Chip). Dielectric laser acceleration of electrons has recently been demonstrated with significantly higher accelerating gradients than other structure-based linear accelerators. Towards the development of an integrated 1 MeV electron accelerator based on dielectric laser accelerator technologies, development in several relevant technologies is needed. In this work, recent developments on electron sources, bunching, accelerating, focussing, deflecting and laser coupling structures are reported. With an eye to the near future, components required for a 1 MeV kinetic energy tabletop accelerator producing sub-femtosecond electron bunches are outlined.
	Slides WEYB1 [12.774 MB]
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WEPAB123	A Phase Matching, Adiabatic Accelerator	electron, laser, plasma, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB123
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WEPAB125	Crossbar H-Mode Drift-Tube Linac Design With Alternative Phase Focusing for Muon Linac	cavity, linac, emittance, dipole	2868
	M. Otani, K. Futatsukawa KEK, Tsukuba, Japan K. Hasegawa, Y. Kondo JAEA/J-PARC, Tokai-mura, Japan R. Kitamura University of Tokyo, Tokyo, Japan S.S. Kurennoy LANL, Los Alamos, New Mexico, USA
	Funding: This work was supported by JSPS KAKENHI Grant Number 15H03666. A crossbar H-mode (CH) drift-tube linac (DTL) is one of alternatives for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. In this poster, dynamics and cavity designs with computer calculations will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB125
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WEPAB132	Research Program and Recent Results at the Argonne Wakefield Accelerator Facility (AWA)	wakefield, experiment, electron, emittance	2885
	M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, Q. Gao, G. Ha, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.Q. Qiu, J.H. Shao, Y.R. Wang, C. Whiteford, E.E. Wisniewski, L.M. Zheng ANL, Argonne, Illinois, USA S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA Q. Gao, L.M. Zheng TUB, Beijing, People's Republic of China G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea N.R. Neveu IIT, Chicago, Illinois, USA Y.R. Wang IMP/CAS, Lanzhou, People's Republic of China
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357 We give an overview of the research program at the Argonne Wakefield Accelerator Facility (AWA), including some highlights of recent experiments. The AWA facility is dedicated to the study of beam physics and the development of technology for future particle accelerators. Two independent electron linacs are used to study wakefield acceleration: 70 MeV high charge electron bunches of up to 100 nC are used to drive wakefields, which can be probed by bunches originating from the same linac or from the 15 MeV linac. Recent Two-Beam-Acceleration (TBA) experiments operating at 11.7 GHz reached accelerating gradients of up to 150 MV/m. No indication of witness beam quality degradation was observed, and bunch charge was preserved during the acceleration process. Two identical TBA setups were used in series in order to demonstrate staging capabilities. Dielectric loaded structures operating at 26 GHz are also used in TBA experiments. Another main thrust of the research program consists of exploring and developing techniques to manipulate the phase space of electron bunches. These efforts include bunch shaping and the exchange of emittances in the transverse and the longitudinal phase spaces
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB132
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WEPVA001	Electron Injector for Multi-Stage Laser-Driven Plasma Accelerators	electron, laser, plasma, simulation	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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WEPVA002	Simulations of DLA Grating Structures in the Frequency Domain	laser, simulation, electron, cavity	3247
	T. Egenolf, O. Boine-Frankenheim, U. Niedermayer TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim GSI, Darmstadt, Germany
	Dielectric laser accelerators (DLA) driven by ultrashort laser pulses can reach orders of magnitude larger gradients than contemporary RF electron accelerators. A new implemented field solver based on the finite element method in the frequency domain allows the calculation of the structure constant, i.e. the ratio of energy gain to laser peak amplitude. We present the maximization of this ratio as a parameter study looking at a single grating period only. Based on this optimized shape the entire design of a beta-matched grating is completed in an iterative process. The period length of a beta-matched grating increases due to the increasing velocity of the electron when a subrelativistic beam is accelerated. The determination of the optimal length of each grating period thus requires the knowledge of the energy gain within all so far crossed periods. Furthermore, we outline to reverse the excitation in the presented solver for beam coupling impedance calculations and an estimation of the beam loading intensity limit.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA002
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WEPVA003	Designing a Dielectric Laser Accelerator on a Chip	laser, electron, bunching, synchrotron	3250
	U. Niedermayer, O. Boine-Frankenheim, T. Egenolf TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work is funded by the Gordon and Betty Moore Foundation (Grant GBMF4744 to Stanford) and the German Federal Ministry of Science and Education (Grant FKZ:05K16RDB). Dielectric Laser Acceleration (DLA) achieves gradients of more than 1GeV/m, which are among the highest in non-plasma accelerators. The long-term goal of the ACHIP collaboration* is to provide relativistic (>1 MeV) electrons by means of a laser driven microchip accelerator. Examples of slightly resonant dielectric structures showing gradients in the range of 70% of the incident laser field (1 GV/m) for electrons with β=0.32 and 200% for β=0.91 are presented. We demonstrate the bunching and acceleration of low energy electrons in dedicated ballistic buncher and velocity matched grating structures. However, the design gradient of 500 MeV/m leads to rapid defocusing. Therefore we present a scheme to bunch the beam in stages, which does not only reduce the energy spread, but also the transverse defocusing. The designs are made with a dedicated homemade 6D particle tracking code. * https://achip.stanford.edu
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA003
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WEPVA004	Simulation of an Electromagnetic Field Excitation by a THz-pulse and Acceleration of an Electron Bunch in a Dielectric-loaded AXSIS Linac	linac, electron, injection, simulation	3253
	K. Galaydych, R.W. Aßmann, U. Dorda, B. Marchetti, G. Vashchenko, I. Zagorodnov DESY, Hamburg, Germany
	Funding: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 609920 The Attosecond X-ray Science: Imaging and Spectroscopy (AXSIS) experiment at DESY will use a dielectric loaded waveguide to accelerate electron bunches up to 15 MeV. Such a linac will be powered by a narrowband multicycle THz-pulse with a central frequency of 300 GHz. In this paper we focus on the reflection of the excited field at a pinhole, on the optimization of the bunch injection time and on the bunch dynamics in the acceleration process. The linac excitation by the THz-pulse and the bunch acceleration in the excited field are investigated using CST and ECHO simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA004
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WEPVA005	Simulation of a Many Period Dielectric Grating-based Electron Accelerator	laser, electron, simulation, emittance	3256
	W. Kuropka, R.W. Aßmann, U. Dorda, F. Mayet DESY, Hamburg, Germany W. Kuropka, F. Mayet University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Funding: GBMF - Gordon and Betty Moore Foundation Dielectric laser driven particle accelerators have become a research area of major interest due to the high acceleration gradients achievable. Those are mainly attributed to the high damage thresholds of dielectrics at optical frequencies. Simulations of these structures are usually computed with Particle-In-Cell (PIC) codes. Their accuracy and self consistency comes with a major drawback of high computation costs. Computation of structures consistent of hundreds to thousands of periods are only viable with High Performance Computing clusters. In this proceeding a compromise of CST* PIC simulations combined with a transfer function model is presented to simulate relativistic electron accelerators for particle energies up to the GeV regime or higher. In addition a simplified example accelerator design is investigated and the required electron bunch parameters from a sub-relativistic source are computed. *CST - Computer Simulation Technology, available from www. cst.com.
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WEPVA006	A Concept for Phase-Synchronous Acceleration of Microbunch Trains in DLA Structures at SINBAD	laser, electron, simulation, linac	3260
	F. Mayet, R.W. Aßmann, J. Bödewadt, R. Brinkmann, U. Dorda, W. Kuropka, C. Lechner, B. Marchetti, J. Zhu DESY, Hamburg, Germany W. Kuropka, F. Mayet University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany J. Zhu University of Hamburg, Hamburg, Germany
	Funding: GBMF - Gordon and Betty Moore Foundation The concept of dielectric laser accelerators (DLA) has gained increasing attention in accelerator research, because of the high achievable acceleration gradients (~GeV/m). This is due to the high damage threshold of dielectrics at optical frequencies. In the context of the Accelerator on a Chip International Program (ACHIP) we plan to inject electron bunches into a laser-illuminated dielectric grating structure. At a laser wavelength of 2 micro-meter the accelerating bucket is <1.5 fs. This requires both ultra-short bunches and highly stable laser to electron phase. We propose a scheme with intrinsic laser to electron synchronization and describe a possible implementation at the SINBAD facility (DESY). Prior to injection, the electron bunch is conditioned by interaction with an external laser field in an undulator. This generates a sinusoidal energy modulation that is transformed into periodic microbunches in a subsequent chicane. The phase synchronization is achieved by driving both the modulation process and the DLA with the same laser pulse. This allows scanning the electron bunch to laser phase and will show the dependence of the acceleration process on this delay.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA006
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WEPVA011	Development of a Laser Driven Dielectric Accelerator for Radiobiology Research	electron, laser, experiment, simulation	3272
	K. Koyama, M. Yoshida KEK, Ibaraki, Japan Z. Chen, H. Okamoto The University of Tokyo, Tokyo, Japan M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
	Funding: This work was supported by KAKENHI, (Grant-in-Aid for Scientific Research) Grant Number 15H03595 and partly supported by NIMS Nanofabrication Platform in Nanotechnology Platform Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. A laser-driven dielectric accelerator below 1 MeV is under development for applying a sub-micron size electron-beam to radiobiological research. Simulations of the electric field and electron trajectories in the proximity of the dielectric structure (transmission grating) were performed in order to fix parameters of the demonstration experiment. Serious deflection of electron beam towards the grating limited the injection phase as well as the height from the structure. The energy gain of 50-keV electron was estimated to be 1 keV in 30-micron length at the optimum condition. Transmission gratings for the experiment were fabricated by using facilities of the NIMS Nanofabrication Platform. In addition to the acceleration experiment using the simple grating, a resonator type accelerator structure was designed for exciting the acceleration field by a moderately small laser.
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WEPVA012	Laser Proton Accelerator with Improved Repeatability at Peking University	laser, target, proton, plasma	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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WEPVA016	Dielectric Laser Accelerator Investigation, Setup Substrate Manufacturing and Investigation of Effects of Laser Induced Electromigration RF Cavity Breakdown Influences	laser, electron, vacuum, controls	3286
	M. Hamberg, M. Jacewicz, J. Ögren Uppsala University, Uppsala, Sweden M. Karlsson, E. Vargas Catalan Uppsala University, Department of Engineering Sciences, Uppsala, Sweden M. Kuittinen, I. Vartiainen UEF, Joensuu, Finland
	Funding: I thank Stockholm Uppsala centre for FEL research for funding. Dielectric laser acceleration (DLA) where the high electric fields in lasers are used to accelerate electrons next to nanofabricated dielectric structures has recently been proven in proof of concept studies. In this paper I describe investigations setup and substrate manufacturing. Additionally we describe using the setup for evaluating RF structure breakdown due to laser induced electromigration occurences.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA016
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WEPVA018	Drive-Witness Acceleration Scheme Based on Corrugated Dielectric mm-Scale Capillary	wakefield, laser, electron, experiment	3292
	K. Lekomtsev, S.T. Boogert, P. Karataev, A. Lyapin JAI, Egham, Surrey, United Kingdom A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan A.A. Tishchenko MEPhI, Moscow, Russia
	Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179. In this paper, we investigate a corrugated mm-scale capillary as a compact accelerating structure in a drive-witness acceleration scheme, and suggest a methodology to measure acceleration of a witness bunch. Two typical measurements and the energy gain in a witness bunch as a function of the distance between bunches are discussed. A corrugated capillary is considered as an accelerator/decelerator with an adjustable wakefield pattern depending on a transverse beam position.
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WEPVA019	Group Velocity Matching in Dielectric-Lined Waveguides and its Role in Electron-THz Interaction	electron, simulation, accelerating-gradient, interface	3296
	A.L. Healy, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom D.M. Graham The University of Manchester, The Photon Science Institute, Manchester, United Kingdom S.P. Jamison STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Terahertz(THz)-driven dielectric-lined waveguides have applications in electron manipulation, particularly acceleration, as the use of dielectric allows for phase velocities below the speed of light. However matching a single frequency to the correct velocity does not maximise electron-THz interaction; waveguide dispersion typically results in an unmatched group velocity and so the pulse envelope of a short THz pulse changes along the length of the structure. This reduces field amplitude and therefore accelerating gradient as the envelope propagates at a different velocity to the electron. Presented here is an analysis of the effect of waveguide dispersion on THz-electron interaction and its influence on structure dimensions and choice of THz pulse generation. This effect on net acceleration is demonstrated via an example of a structure excited by a single-cycle THz pulse, with a comparison of multi-cycle, lower intensity THz pulses on net acceleration.
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WEPVA022	RECENT TWO-BEAM ACCELERATION ACTIVITIES AT ARGONNE WAKEFIELD ACCELERATOR FACILITY	experiment, accelerating-gradient, wakefield, impedance	3305
	J.H. Shao, S.P. Antipov, M.E. Conde, W. Gai, Q. Gao, G. Ha, W. Liu, N.R. Neveu, J.G. Power, Y.R. Wang, E.E. Wisniewski, L.M. Zheng ANL, Argonne, Illinois, USA C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA J. Shi, D. Wang TUB, Beijing, People's Republic of China
	The Two-Beam Acceleration (TBA) is a modified approach to the structure-based wakefield acceleration which may meet the luminosity, efficiency, and cost requirement of a future linear collider. Recently, various TBA experiments have been carried out at the Argonne Wakefield Accelerator Facility (AWA). With X-band metallic power extractors and accelerators, a 70 MeV/m average accelerating gradient has been demonstrated in two stages while a 150 MeV/m gradient as well as 300 MW extracted power have been achieved in a single stage. In addition, low cost K-band dielectric power extractor and accelerator have also been developed. The preliminary results show power extraction of 55 MW and an average accelerating gradient of 28 MeV/m.
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WEPVA054	Study of The New Return Yoke for The Upgraded Superconducting Cyclotron of INFN-LNS	extraction, ion, cyclotron, experiment	3381
	A. Calanna, L. Allegra, L. Calabretta, G. Costa, G. D'Agostino, G. Gallo, D. Rifuggiato, A.D. Russo INFN/LNS, Catania, Italy G. D'Agostino Universita Degli Studi Di Catania, Catania, Italy
	The LNS Superconducting Cyclotron (CS) has been working for 20 years making available a wide range of ions and energies. Its operational diagram is peculiar and many experiment are performed each year. In the near future a major upgrade is planned. This will allow to overcome the major limitation of the CS, which is the beam power limited at 100 W. In the new version of the CS, the extracted beam power will be increased up to a factor 100. This improvement will be reached adding a new extraction line dedicated to a specific set of light ions and energies extracted by stripping. The new design could affect the beam dynamics strongly. Indeed, the iron yoke penetrations don't respect the three folds symmetry of our cyclotron. This inhomogeneity produces unwanted field harmonics, which have to be reduced as much as possible to avoid beam precession or second order effects. Here the study accomplished to minimize the perturbation of the non-three fold field symmetry using the current sheet approximation (CSA) is presented, along with the state-of-art configuration of the updated cyclotron
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THPAB014	An Adaptive Mesh-Based Method for the Efficient Simulation of LSC-Driven Microbunching Gain in FEL Applications	electron, FEL, bunching, simulation	3720
	Ph. Amstutz University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany M. Vogt DESY, Hamburg, Germany
	Electron beams with high peak current as they are required for the operation of free-electron lasers (FELs) are often generated by means of a series of magnetic bunch compressors. In conjunction with a collective coherent force, e.g. longitudinal space-charge (LSC), bunch compressors can possibly cause a wavelength dependent amplification of initial density inhomogeneities, potentially to an extent detrimental to the operation of the FEL. A common model, consisting of LSC, acceleration (kicks), and magnetic chicanes (drift-type maps), is governed by a time-discrete Vlasov-Poisson system. Such systems have been successfully simulated using mesh based representations of the phase space density (PSD) and the method of characteristics for the update step. However, for the irregular and exotic PSDs, prevalent in FEL applications, a homogeneous high resolution discretization on a naive rectangular mesh can be prohibitively wasteful. Here we present an approach based on adaptive tree refinement that addresses the complexity of the PSDs and allows for the efficient simulation of LSC-driven micro-bunching in FELs.
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THPAB024	Emittance Growth at Charge-Exchanging Multi-Turn Injection in KURRI FFAG	injection, emittance, scattering, simulation	3747
	T. Uesugi, Y. Ishi, Y. Kuriyama, Y. Mori Kyoto University, Research Reactor Institute, Osaka, Japan
	In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor institute (KURRI), rapid beam loss of factor 100 is observed right after the injection. In the synchrotron, charge-exchanging multi-turn injection is adopted with a stripping foil located on the closed orbit of the injection energy. No bump orbit system is used and the injected beams escape from the foil according to the closed-orbit shift by acceleration. The particles hit the foil many times and that is why the emittance grows up during the injection. In this paper, simulation studies are done to estimate the emittance growth and beam losses. The scattering effect at the foil is modeled by GEANT4.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB024
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THPAB025	Simulation Studies of Transverse Beam Instabilities and Measures Beyond 1 MW Beam Power in the 3-GeV RCS of J-PARC	impedance, simulation, injection, extraction	3750
	P.K. Saha, H. Hotchi, Y. Shobuda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The transverse impedance of the extraction kicker magnets is a significant beam instability source in the 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex). The systematic simulation studies for beam instability by including the space charge effect has been done by using the ORBIT code. The simulation results are well reproduced in the corresponding measurements. The designed 1 MW beam power has recently been accomplished by keeping sextuple magnets off in order to stabilize the beam by utilizing the large lattice chromaticity throughout the entire acceleration period. The RCS simultaneously delivers extracted beam to the MLF (Material and Life Science Experimental Facility) and the MR (Main Ring). In order to ensure 1 MW beam power at the MLF even when RCS beam sharing to the MR is twice increased as well as when a second target station is constructed at the MLF, a beam power of 1.5 MW has to be realized in the RCS. However, the simulation shows that beyond 1 MW the beam is unstable even if no chromaticity is corrected. A reduction of the kicker impedance by at least a half is required in order to achieve 1.5 MW beam power in the RCS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB025
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THPAB034	Generation of Short Intense Heavy-Ion Pulses in HIAF	ion, injection, heavy-ion, cavity	3774
	D.Y. Yin, H. Du, L.J. Mao, G.D. Shen, J.W. Xia, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	The HIAF is a new accelerator complex under design at IMP to provide intense primary and radioactive ion beams for nuclear physics, atomic physics, high energy density physics and other applications. As a key part of HIAF, the Booster Ring (BRing) is designed to accumulate and accelerate heavy ion beams provided by iLinac up to high intensity and energy. The high quality, well focused, strongly bunched intense Uranium beam (U³⁴⁺) with high energy and high intensity of 10¹¹ will open a new area for the HED physics research in laboratory. Based on the beam parameters of 238U³⁴⁺ proposed by the BRing, the two critical issues of producing short bunch with high beam intensity are studied. One is efficiency of adiabatic capture which can be a necessary prerequisite to ensure the beam intensity, and the other one is bunch compression in longitudinal which is an effective way of producing short pulse duration bunch. In this article, the analytical calculations and tracking simulations are described, the capture efficiency and possible bunch length under the action of planning RF system are presented
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THPIK059	Experimental Study on PM-AM Method in Pulse Compression System	LLRF, klystron, experiment, cavity	4230
	P. Wang, H.B. Chen, C. Cheng, M.M. Peng, J. Shi, X.W. Wu, J. Yang, H. Zha TUB, Beijing, People's Republic of China
	We experimentally demonstrate the PM-AM method (Phase Modulation to Amplitude Modulation) at the S-band high power test stand, which consists of two S-band klystrons, a SLED type pulse compressor and two high power stainless steel RF loads, in Tsinghua University. A LLRF (low level RF) system has been developed to modulate the phases of the two klystrons in real time such that pulse compressor could generate a flat output pulse. Experimental results presents that the efficiency of the pulse compression system is 45% and the power gain is 2.9.
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THPIK110	RF Cavity Design for a Low Cost 1 MeV Proton Source	cavity, proton, simulation, impedance	4355
	D. Soriano Guillén, R. Seviour University of Huddersfield, Huddersfield, United Kingdom S. Hunt Alceli Accelerator Technology Ltd., Huddersfield, United Kingdom
	In this paper we present the design for a low-cost RF cavity capable of accelerating protons from 100 keV to 1 MeV. The system is designed to meet the specifications from the proposed Alceli LTD medical proton therapy linac, to deliver a 1 nA proton beam current with a 1 kHz repetition rate. We present a design of an RF normal conducting (NC) re-entrant Cu cavity operating at 40 MHz consisting of a coupled two cavity system, both driven by a single Marx generator. The choice of such a low operating frequency for the cavity system enables us to use a relatively low-cost cost Marx Generator as the RF source. Marx generators work in a similar fashion to a Cockcroft-Walton accelerator (without the expensive components), creating a high-voltage pulse by charging a number of capacitors relatively slowly in parallel, then rapidly discharging in series, via spark gaps. Marx generators can deliver 2.5 GW, 1 ns pulses, with rise times of 200 ps, and (relatively) low jitter.
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THPVA017	Integer Spin Resonance Crossing With Preserving Beam Polarization on VEPP-4M	polarization, resonance, solenoid, experiment	4451
	A.K. Barladyan, A.Yu. Barnyakov, S.A. Glukhov, S.E. Karnaev, E.B. Levichev, S.A. Nikitin, I.B. Nikolaev, I.N. Okunev, P.A. Piminov, A.G. Shamov, A.N. Zhuravlev BINP SB RAS, Novosibirsk, Russia
	The method to preserve the electron beam polarization on the VEPP-4M storage ring during acceleration with crossing the integer spin resonance energy E=1763 MeV is described. It is based on the use of the non-compensated longitudinal magnetic field of the KEDR detector. This method has been successfully applied for the needs of the R measurement experiment.
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THPVA072	Travelling Laser Focus System for the Particles Acceleration	laser, radiation, emittance, photon	4613
	A.A. Mikhailichenko Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We describe the result of the wake-fields calculation in a device for acceleration of particles in the micro-structures illuminated by the swept laser bust. Calculations carried with help of FlexPDE code.
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THPVA082	Multi-Energy Trial Operation of the HIT Medical Synchrotron: Accelerator Model and Data Supply	ion, synchrotron, extraction, controls	4644
	M. Galonska, E. Feldmeier, Th. Haberer, A. Peters, C. Schömers HIT, Heidelberg, Germany
	At the Heidelberg ion beam therapy center (HIT) cancer patients are treated with the raster-scanning dose delivery method of heavy ion pencil beams. The beams are provided by a synchrotron which allows for a variation of the ion penetration depth by changing the ion beam energy for each synchrotron cycle. In order to change the beam energy within one synchrotron cycle the accelerator model and data supply model within the control system have been extended extensively. In this first data supply model beam re-acceleration or deceleration between two arbitrary extraction energies is defined. The model defines an additional transition phase, i.e. current/set value patterns between extraction and the re-acceleration yet giving the possibility of setting the beam properties suitable for further acceleration/deceleration. This includes the dipoles, correctors, quadrupoles, sextupoles, KO-Exciter (spill break), and RF. This allowed for the survey and optimisation of the beam properties including possible beam losses of the re-accelerated, transversally blown up beam for arbitrary energy levels.
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THPVA083	First Tests of a Re-accelerated Beam at Heidelberg Ion-Beam Therapy Centre (HIT)	synchrotron, extraction, ion, operation	4647
	C. Schömers, E. Feldmeier, M. Galonska, Th. Haberer, J.T. Horn, A. Peters HIT, Heidelberg, Germany
	In the active raster scanning method performed at HIT since 2009, tumors are irradiated slice-by-slice by changing the extraction energy. The synchrotron provides a library of 255 different extraction-energy levels per ion type, according to the aimed penetration depth. So far, a new synchrotron cycle is started for each iso-energy-slice resulting in a non-optimal duty cycle. In order to reduce treatment time and to increase the number of patients treated per day, synchrotron cycles with several extraction flattops on different energy levels are planned. After completing one iso-energy-slice, remaining particles will be reaccelerated to the adjacent level. As a first test a new data supply model generating patterns for power supplies and RF devices with two different extraction flattops has been implemented recently. The properties of the reaccelerated beam are now under detailed examination. The reaccelerated beam was successfully extracted and guided to the experimental area. Ionization chambers along the beam line clearly show two spills on two different extraction flattops. The desired change of beam energy has been verified by range measurements in a water column.
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THPVA133	HEATHER - HElium Ion Accelerator for RadioTHERapy	ion, proton, resonance, injection	4768
	J. Taylor, T.R. Edgecock University of Huddersfield, Huddersfield, United Kingdom S. Green University Birmingham, Birmingham, United Kingdom C. Johnstone Fermilab, Batavia, Illinois, USA
	A non-scaling fixed field alternating gradient (nsFFAG) accelerator is being designed for helium ion therapy. This facility will consist of 2 superconducting rings, treating with helium ions (He²⁺ ) and image with hydrogen ions (H + 2 ). Currently only carbon ions are used to treat cancer, yet there is an increasing interest in the use of lighter ions for therapy. Lighter ions have reduced dose tail beyond the tumour compared to carbon, caused by low Z secondary particles produced via inelastic nuclear reactions. An FFAG approach for helium therapy has never been previously considered. Having demonstrated isochronous acceleration from 0.5 MeV to 900 MeV, we now demonstrate the survival of a realistic beam across both stages.
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Paper

Title

Other Keywords

Page

MOZB1

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

laser, target, plasma, electron

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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MOPAB075

Measurement of Electron Bunch Length via a Tunable-Gap Undulator

radiation, electron, undulator, laser

295

X.L. Su, Y.-C. Du, W.-H. Huang, L. Niu, C.-X. Tang, Q.L. Tian, D. Wang, L.X. Yan
TUB, Beijing, People's Republic of China
Y.F. Liang
Tsinghua University, Beijing, People's Republic of China

A THz undulator with widely tunable gap is constructed and installed at Tsinghua University beamline, which is applied for narrow-band THz radiation and measurements of electron bunch longitudinal structure. This is a planar electromagnetic device with 8 regular periods, each 10 cm long. The field range B=0.15- 0.99 T peak field on axis while changing the gap from 75mm to 23mm. In the experiments, we scanned the undulator gap to measure the radiation intensity at different resonant frequency, thus we can get the bunch length even form factor of the bunch. The demonstrated experimental results show that the bunch of 220pC compressed by chicane in Tsinghua beamline is about 120fs (rms), which agree well with the simulations. The resolution of bunch length measurement with this method can be attoseconds by optimized undulator. Furthermore, the form factor of electron bunch train can also be measured.

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MOPIK004

Demonstration of an All-Optically Driven Sub-keV THz Gun

electron, gun, laser, operation

503

W.R. Huang, K.-H. Hong, F.X. Kärtner, E.A. Nanni, KR. Ravi
MIT, Cambridge, Massachusetts, USA
A-L. Calendron, H. Cankaya, A. Fallahi, F.X. Kärtner, X. Wu
CFEL, Hamburg, Germany
D. Zhang
DESY, Hamburg, Germany

Funding: European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920
Intense ultrashort THz and optical pulses with single-cycle pulse duration became possible after the recent advances in ultrafast technologies. Using such ultrashort pulses for electron acceleration offers advantages in terms of higher thresholds for material breakdown which opens up a promising path towards increased acceleration gradients. In addition, using optically generated THz pulses enable inherently synchronized acceleration schemes, since accelerating field and particle injecting field are excited by a single seed laser. In this contribution, we present the first experimental demonstration of laser-driven THz acceleration of electrons initially at rest. It is shown that strong-field, single-cycle THz fields accelerate electrons with peak energies of up to 0.8 keV in an ultracompact THz gun with bunch charge of 40 fC. The achieved energy spreads are as low as 5.8%.

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MOPIK005

Compact Electron Injectors Using Laser Driven THz Cavities

cavity, electron, gun, laser

506

M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis, A. Yahaghi
CFEL, Hamburg, Germany
R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, G. Vashchenko, T. Vinatier, D. Zhang, C. Zhou
DESY, Hamburg, Germany

We present ultra-small electron injectors based on cascaded cavities excited by short multi-cycle THz signals. The designed structure is a 3.5 cell normal conducting cavity operating at 300 GHz. This cavity is able to generate pC electron bunches and accelerate them up to 250 keV using less than 1 mJ THz energy. Unlike conventional RF guns, the designed cavity operates in a transient state which, in combination with the high frequency of the driving field, makes it possible to apply accelerating gradients as high as 500 MV/m. Such high accelerating gradients are promising for the generation of high brightness electron beams with transverse emittances in the nm-rad range. The designed cavity can be used as the injector for a compact accelerator of low charge bunches.

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MOPIK007

THz Driven Electron Acceleration with a Multilayer Structure

electron, laser, gun, dipole

512

D. Zhang, M. Fakhari, W. Qiao, C. Zhou
DESY, Hamburg, Germany
F. Ahr, A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, F.X. Kärtner, F. Lemery, N.H. Matlis, X. Wu
CFEL, Hamburg, Germany
W.R. Huang, F.X. Kärtner
MIT, Cambridge, Massachusetts, USA
C. Zhou
University of Hamburg, Hamburg, Germany

We present first results in THz-based electron acceleration using a novel multilayer structure which we dub a Butterfly LINAC. THz-based accelerators are mm-scale devices that bridge the gap between micron-scale, ultra-compact devices such as laser-plasma accelerators (LPAs) and dielectric laser accelerators (DLAs) and meter-scale conventional accelerators. These intermediate-scale devices are promising because they combine many of the benefits of LPAs and DLAs, such as intrinsic synchronization and high acceleration gradients with the benefits of conventional accelerators such as high charge capacity, tunability as well as the robustness, stability and simple fabrication of static, macroscopic acceleration structures. The Butterfly LINAC allows optimization of electron acceleration using transversely-coupled single-cycle THz pulses by phase-matching electrons with the driving field. Proof-of-concept experiments will be described demonstrating 10 keV energy gain of a 55 keV source, in good agreement with simulation. Scalability of this device to the MeV level and applicability towards free electron lasers and ultrafast electron diffractometers will also be discussed.

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MOPIK017

Simultaneous Generation of Drive and Witness Beam for Collinear Wakefield Acceleration

wakefield, emittance, controls, quadrupole

535

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
Generating the drive and witness bunch for collinear wakefield acceleration (CWFA) requires precise control of the longitudinal bunch shape for each bunch as well as the controlling their separation. The emittance exchange (EEX) beamline and a transverse mask can be used to achieve all of these requirements. First, this EEX-based method can independently control the longitudinal bunch shape of each bunches so that the drive bunch is shaped to generate a high transformer ratio while witness bunch is shaped to suppress its energy spread. Second, the timing jitter between the drive and witness bunch poses a serious limitation to the CWFA scheme but the EEX-based method eliminates this since both bunches are generated at the same time and share the exactly same beamline so there are no relative errors. In this paper, we confirm the feasibility of this EEX-based method for simultaneous generation with simulation for CWFA in a dielectric structure.

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MOPIK018

Micro-Scale Electron Beam Generation Using Pyroelectric Crystals

electron, laser, injection, diagnostics

538

R.B. Yoder, Z. Kabilova
Goucher College, Baltimore, Maryland, USA

Novel laser-powered acceleration structures currently under development, which have dimensions comparable to optical wavelengths and can be constructed on a silicon wafer, require injection of a sub-micron-scale electron bunch to achieve high-quality, monoenergetic output beams. A potential injection mechanism for such micro-scale beams relies on field emission from a nanotip array, followed by acceleration to near-relativistic energies. We demonstrate field emission of electrons from a lithium niobate crystal during heating and cooling, and describe the production of electrons within a hollow channel along the axis of a lithium niobate crystal. Measurements of emitted beam properties are compared with direct measurements of crystal fields under comparable conditions and modeled mathematically.

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MOPIK021

Generation of Transversely Segmented Beam Using a Nano-Patterned Photocathode

cathode, laser, simulation, gun

545

A. Lueangaramwong, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
G. Andonian
RadiaBeam, Santa Monica, California, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: Work supported by US Department of Energy (DOE) contract DE-SC0009656 with Radiabeam Technologies and by NSF grant PHY-1535401 with Northern Illinois University.
Plasmonic photocathodes – nano-patterned photocathodes with periodicity comparable to the excitation laser – have demonstrated enhanced quantum efficiency. In the present paper we present numerical simulations of the beam dynamics associated to the emission process from this type of cathodes and to the subsequent acceleration to relativistic energies by combining WARP and IMPACT-T programs. We especially consider the possibility to transversely image the cathode surface at high energy and enable the generation of transversely segment beams.

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MOPIK068

Beam Dynamics Design Parameters for KONUS Lattices

lattice, linac, cavity, emittance

683

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

The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept has been successfully applied on several linacs, some of them in routine operation since decades. However, the KONUS lattice parameters optimization is often done in a results-oriented approach, depending on the designers' experience. This paper focuses on the description of the longitudinal beam motion along one KONUS lattice period. A test lattice is used for demonstrating the potential of KONUS lattices with respect to stable, periodic beam motion with emittance growth rates similar to those of conventional designs. The main objective of this ongoing work is to derive more general rules for the parametrization of KONUS lattices.

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MOPIK115

A Design for 10 GeV, High Peak-Current, Tightly Focused Electron Beams at FACET-II

emittance, linac, electron, simulation

807

G.R. White
SLAC, Menlo Park, California, USA

Funding: This work was sponsored by the Department of Energy under Contract Number: DE-AC02-76SF00515
FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The design consists of a 135-MeV high-brightness photo-injector constructed in an off-axis injection line in Sector 10 of the SLAC Linac, two new 4-bend chicane bunch compressors installed in Sectors 11 and 14, with a third compression stage provided by the existing FACET W Chicane in Sector 20. We develop a design to deliver peak currents more than 160 kA to the Sector 20 interaction region at 10 GeV, with 10 'm-rad emittances at 2 nC bunch charge and 1.4 % rms energy spread. The Sector 20 bunch compressor is re-designed for maximum peak current throughput and minimal emittance degradation via CSR, and the FACET-II compression scheme is optimized. We present 6D start-end beam tracking simulations using Lucretia including ISR, CSR, wakefields and space charge effects.

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MOPIK117

On the Computation of Phase and Energy Gain for a Thin-Lens RF Gap Using a General Field Profile

simulation, linac, factory, cavity

810

C.K. Allen
ORNL, Oak Ridge, Tennessee, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC05-00OR22725.
The thin-lens representation for an RF accelerating gap has been well developed and is documented by Lapostolle [5], Weiss [6], Wangler [14], and others [9], [10]. These models assume that the axial electric field is both centered and symmetric so it has a cosine expansion. Presented here is a model that considers general axial fields. Both the cosine and sine transit time factors are required plus their Hilbert transforms. The combination yields a complex Hamiltonian rotating in the complex plane with the synchronous phase. The phase and energy gains are computed in the pre-gap and post-gap regions then aligned with asymptotic values of wave number. Derivations are outlined, examples are shown, and simulations presented.

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MOPVA012

The Dedicated Accelerator R&D Facility Sinbad at DESY

linac, electron, laser, experiment

869

U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu
DESY, Hamburg, Germany
A. Fallahi, F.X. Kärtner, N.H. Matlis
CFEL, Hamburg, Germany

We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.

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MOPVA013

Application of Non-Isochronous Beam Dynamics in ERLs for Improving Energy Spread and Beam Stability

linac, electron, operation, recirculation

873

F. Hug
IKP, Mainz, Germany

Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128
Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a non-isochronous recirculation scheme the recirculation paths provide a non-zero longitudinal dispersion while the accelerating field is operated at a certain phase off-crest with respect to the maximum. In few turn linacs like ERLs and in microtrons non-isochronous beam dynamics can be used to reduce the energy spread by cancelling out any rf-jitters coming from the linac cavities. To do so the longitudinal phase advance needs to be tuned to a half-integer number of oscillations in longitudinal phase space. Then the total energy spread after main linac acceleration conserves the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. Such concept provides an inherent beam stability and has been introduced many years ago [*] and proven to work successfully in a few-turn recirculator already [**]. We will present beam dynamics calculations for the application of nonisochronous beam dynamics in single- and multi-turn energy recovery linacs at different longitudinal working points.
[*] H. Herminghaus, NIM. A 314 (1992) 209.
[**] F. Hug et al., Proc. of LINAC '12 (2012) 531.

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MOPVA014

Injector Linac Stability Requirements for High Precision Experiments at MESA

experiment, linac, electron, operation

876

F. Hug, R.G. Heine
IKP, Mainz, Germany

Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128
MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [*,**]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals.
[*] H. Herminghaus, NIM. A 314 (1992) 209.
[**] F. Hug et al., Proc. of LINAC '12 (2012) 531.

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MOPVA145

Improvements on CNAO Accelerator for Ocular Treatments

extraction, proton, injection, synchrotron

1194

L. Falbo, E. Bressi, C. Priano
CNAO Foundation, Milan, Italy

Ocular melanoma has been successfully treated worldwide since many years using proton beams. CNAO is the only Italian hadrontherapy facility able to treat tumours with both proton and carbon ion high-energy scanning beams accelerated by a synchrotron; the machine was commissioned in 2011 and more than 1000 patients have been treated so far. With respect to the othercases, , ocular melanoma treatment needed important changes both under the medical physics and machine physics points of view. The main goal of this work is to describe the changes in the machine set up to increase the proton current by a factor of 5, this task representing a sort of recommissioning of the synchrotron.

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MOPVA146

Optimization of Carbon Treatments at CNAO

dipole, extraction, feedback, ion

1197

L. Falbo, E. Bressi, C. Priano
CNAO Foundation, Milan, Italy

CNAO facility is treating patients with carbon ion beams since 2012. Often carbon ions are used to treat tumors with great volumes that causes long time irradiations: this represents a complaint for the patient, a limit in the number of treatable patients per day and an increase in the cost of the treatment itself. An effort has been done in the last year to increase the particle intensity in order to reduce the irradiation time for the carbon treatments: this article illustrates the changes in the machine done to achieve this goal.

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TUOBB3

HORIZON 2020 EuPRAXIA Design Study

plasma, laser, electron, 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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TUZB1

Final Results From the Clic Test Facility (CTF3)

linac, operation, emittance, beam-loading

1269

R. Corsini
CERN, Geneva, Switzerland

The unique CLIC TEST Facility (CTF3) has been built more than a decade ago to demonstrate the feasibility of the CLIC two beam acceleration scheme. The emphasis was one the high current drive beam generation using a fully loaded highly efficient linac and a complex combination scheme to increase beam current and bunch repetition frequency. This drive beam has been used for deceleration experiments and two beam acceleration. A wealth of relevant results for accelerator physics even beyond CLIC has been obtained and will be presented. The rf to beam efficiency of the linac exceeds 95%, after combination the 28 A drive beam with 12 GHz bunch repetition rate has been used to extract more than 50% of its energy producing 1.3 GW of 12 GHz power as well as performing two beam acceleration at 12 GHz with gradients up to 150 MV/m.

Slides TUZB1 [23.702 MB]

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TUOCB3

CBETA - Cornell University Brookhaven National Laboratory Electron Energy Recovery Test Accelerator

electron, linac, permanent-magnet, gun

1285

D. Trbojevic, S. Bellavia, J.S. Berg, M. Blaskiewicz, S.J. Brooks, K.A. Brown, W. Fischer, F.X. Karl, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
BNL, Upton, Long Island, New York, USA
N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, B.M. Dunham, R.G. Eichhorn, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, B.K. Heltsley, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Douglas
JLab, Newport News, Virginia, USA
D. Jusic, J.R. Patterson
Cornell University, Ithaca, New York, USA

Funding: New York State Energy Research and Development Authority (NYSERDA)
Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first SRF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the the linac to form an Electron Energy Recovery (ERL) system. Electron beam from the 6 MeV injector is injected into the 36 MeV superconducting linac, and accelerated by four successive passes: from 42 MeV up to 150 MeV using the same NS-FFAG structure made of permanent magnets. After the maximum energy of 150 MeV is reached, the electron beam is brought back to the linac with opposite Radio Frequency (RF) phase. Energy is recovered and reduced to the initial value of 6 MeV with 4 additional passes. There are many novelties: a single NS-FFAG structure, made of permanent magnets, brings electrons with four different energies back to the linac. A new adiabatic NS-FFAG arc-to-straight section merges 4 separated orbits into a single orbit in the straight section.

Slides TUOCB3 [41.888 MB]

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TUPAB038

Electron Acceleration With a Ultrafast Gun Driven by Single-Cycle Terahertz Pulses

electron, gun, timing, laser

1406

C. Zhou, F. Ahr, A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis, W. Qiao, X. Wu, D. Zhang
CFEL, Hamburg, Germany
R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, G. Vashchenko, T. Vinatier
DESY, Hamburg, Germany

Funding: This work was supported by the European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920.
We present results on an improved THz-driven electron gun using transversely-incident single-cycle THz pulses using a horn-coupler. Intrinsic synchronization between the electrons and the driving field was achieved by using a single laser system to create electrons by UV photoemission and to create THz radiation by difference frequency generation in a tilted-pulse front geometry. Details of the optical setups for the UV and THz pulses will be described as well as preliminary results showing evidence of electron acceleration.

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TUPAB040

Status Update of the SINBAD-ARES Linac Under Construction at DESY

linac, electron, diagnostics, laser

1412

B. Marchetti, R.W. Aßmann, S. Baark, U. Dorda, C. Engling, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, M. Körfer, B. Krause, G. Kube, J. Kuhlmann, S. Lederer, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, A. Petrov, S. Pfeiffer, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, S. Vilcins, M. Werner, Ch. Wiebers, L. Winkelmann, K. Wittenburg, J. Zhu
DESY, Hamburg, Germany

ARES (Accelerator Research Experiment at Sinbad) is a linear accelerator for the production of low charge (from few pC to sub-pC) electron bunches with 100 MeV energy, fs and sub-fs duration and excellent arrival time stability. This experiment is currently under construction at DESY Hamburg and it is foreseen to start operation by the beginning of 2018 with the commissioning of the RF-gun. After an initial beam characterization phase, ARES will provide high temporal resolution probes for testing novel acceleration techniques, such as Laser driven plasma Wake-Field Acceleration (LWFA), Dielectric Laser Acceleration (DLA) and THz driven acceleration. In this work we present an overview of the present design of the linac with a special focus on 3D integration and planned installation phases of the beamline.

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TUPIK009

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

plasma, laser, electron, injection

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

plasma, laser, electron, wakefield

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

plasma, laser, electron, emittance

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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TUPIK018

Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ

plasma, wakefield, 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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TUPIK022

Innovative Single-Shot Diagnostics for Electrons From Laser Wakefield Acceleration at FLAME

laser, electron, target, emittance

1727

F.G. Bisesto, M.P. Anania, E. Chiadroni, A. Curcio, M. Ferrario, R. Pompili
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of electrons to GeV energy in few centimeters. Here we present all the plasma related activities currently underway at SPARC_LAB exploiting the high power laser FLAME. In particular, we will give an overview of the single shot diagnostics employed: Electro Optic Sampling (EOS) for temporal measurement and optical transition radiation (OTR) for an innovative one shot emittance measurements. In detail, the EOS technique has been employed to measure for the first time the longitudinal profile of electric field of fast electrons escaping from a solid target, driving the ions and protons acceleration, and to study the impact of using different target shapes. Moreover, a novel scheme for one shot emittance measurements based on OTR, developed and tested at SPARC_LAB LINAC, used in an experiment on electrons from laser wakefield acceleration still undergoing, will be shown.

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TUPIK023

Gas-filled Capillaries for Plasma-Based Accelerators

plasma, 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

plasma, simulation, injection, 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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TUPVA061

Beam Dynamics Study for the HIM&GSI Heavy Ion SC CW-LINAC

cavity, linac, ion, simulation

2217

S. Yaramyshev, W.A. Barth, M. Heilmann
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia
M. Basten, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

A sc cw-linac with variable output energy from 3.7 to 7.5 MeV/u for ions with mass to charge ratio of A/Z<6 is recently under development at HIM and GSI. Following the results of the latest RF-tests with the newly constructed sc CH-DTL cavity, even heavier ions up to Uranium 28+ could be potentially accelerated with the already reached higher RF-voltage. Also the possibility for an up to 10 MeV/u increased output energy, using the same 13 independent cavities, is under consideration. All these options require an advanced beam dynamics layout, as well as a versatile procedure for transverse and longitudinal beam matching along the entire linac. The proposed algorithms are discussed and the obtained simulation results are presented.

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TUPVA088

Observing Suppression of Syncrotron Oscillation Amplitudes

synchrotron, betatron, dipole, cavity

2284

K. Jimbo
Kyoto University, Kyoto, Japan

We proposed a method to reduce loosing particles in acceleration stage of synchrotrons. A slowly varying horizontal electrostatic field may be useful to de-excite synchrotron oscillations. Then we have to somehow observe the damping of amplitudes of synchrotron oscillations to confirm the effect. We assume that the synchrotron component of rationalized Hamiltonian in acceleration stage is kept constant. Our experimental results did not contradict with this assumption. Taking advantage of this assumption, we can easily confirm the damping of synchrotron oscillation amplitudes experimentally through the increase of synchrotron frequencies.
jimbo@iae.kyoto-u.ac.jp

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TUPVA092

An Upgrade Scenario of RF System to Achieve 1.6 MW Beam Acceleration in J-PARC RCS

cavity, power-supply, resonance, impedance

2297

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

The J-PARC RCS has successfully accelerated 1 MW equivalent proton beam. However, the beam commissioning results and the particle tracking simulation suggest that the RCS has possibility to accelerate up to 1.6 MW beam. Since the power supply of the rf system almost reaches the limit under the condition of 1 MW beam, we consider the possible upgrade scenario of the rf system to accelerate 1.6 MW beam.

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TUPVA097

First Trial of the Muon Acceleration for J-Parc Muon g-2/edm Experiment

rfq, linac, diagnostics, target

2311

R. Kitamura
University of Tokyo, Tokyo, Japan
S. Bae, B. Kim
SNU, Seoul, Republic of Korea
Y. Fukao, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
H. Iinuma
Ibaraki University, Hitachi, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
G.P. Razuvaev
BINP SB RAS, Novosibirsk, Russia
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 16H03987 and 16J07784.
J-PARC E34 experiment aims to measure the muon g-2 and EDM precisely with the unique approach. The muon acceleration is the one of the most critical technique to achieve the goal of the sensitivity. The world's first muon LINAC is planed toward the muon acceleration to 212 MeV in J-PARC. The first trial of the muon acceleration is planed in the early 2017 with the J-PARC prototype RFQ ahead of the construction of the actual muon LINAC. The slow muon source is required for the RFQ test, since the input energy of the RFQ is 5.6 keV. The slow muon produced by the deceleration using the thin aluminum foil was observed. The demonstration of the muon extraction with 7 keV by the electrostatic accelerator called SOA lens was also done. The low-energy muon beam profile monitor (muon BPM) for the measurement of the beam intensity and profile in order to estimate the beam emittance was tested using the surface muon beam. The simulation for the beam emittance measurement has been developed. In this paper, the latest preparation status for the RFQ and the prospects for the muon acceleration test in J-PARC will be presented.

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TUPVA100

High Power Conditioning and First Beam Acceleration of the CSNS DTL-1

DTL, cavity, vacuum, linac

2320

Y. Wang, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu
CSNS, Guangdong Province, People's Republic of China
Q. Chen, M.X. Fan, K.Y. Gong, H.C. Liu
IHEP, Beijing, People's Republic of China

The CSNS DTLs are divided into 4 cavities. The DTL-1 was transferred and installed in the CSNS Linac tunnel in August of 2015. The RF high power conditioning of DTL-1 started in December 2015 and ended in February 2016. At the end, we finished DTL-1 high power conditioning mission with peak power 1.5MW (1.1 times design value), 1.625% duty factor (650us, 25Hz). And the first beam has been successfully accelerated to the design value 21.6MeV with nearly 100% transmission efficiency. In this paper, the details of conditioning process were presented and one severe RF discharge breakdown was described specifically, which occurred during high power conditioning.

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TUPVA112

Acceleration of Polarized Proton and Deuteron Beams in Nuclotron at JINR

resonance, proton, polarization, betatron

2349

Y. Filatov, A.V. Butenko, A.D. Kovalenko, V.A. Mikhaylov
JINR, Dubna, Moscow Region, Russia
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

The superconducting synchrotron Nuclotron allows one to accelerate proton and deuteron beams up to 13.5 GeV/c. The beam depolarization occurs at the crossing of spin resonances. For deuterons, the vertical polarization is preserved almost to the maximum momentum. Tens of spin resonances are crossing during the proton acceleration. The proton polarization will be preserved by a solenoidal 5% snake up to 3.4 GeV/c at the field ramp rate of 1 T/s. It is planned to use a partial 50% snake to eliminate the resonant depolarization of the proton beam in the total momentum range of the accelerator. The results of simulations and experimental data are presented.

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TUPVA113

The Feature of Magnetic Field Formation of Multi-Purpose Isochronous Cyclotron DC280

cyclotron, ion, extraction, ion-source

2352

I.A. Ivanenko, B. Gikal, G.G. Gulbekyan
JINR, Dubna, Moscow Region, Russia
V.P. Kukhtin, E.A. Lamzin, S.E. Sytchevsky
NIIEFA, St. Petersburg, Russia

At the present time the activities on creation of the new heavy-ion isochronous cyclotron DC280 are carried out at Joint Institute for Nuclear Research. The isochronous cyclotron DC-280 will produce accelerated beam of ions A/Z= 4 - 7 with a smooth variation of the beam energy W= 4 ' 8 MeV/n. The variation of energy is provided by the wide range of the magnetic field levels from 0.64T till 1.32T and usage of the 11 radial and 4 pairs of harmonic correcting coils. In the work the results of calculations and final measurements of the magnetic field are presented. The magnetic field of cyclotron DC-280 is formed in a good conformity with results of computer modeling.

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WEYB1

Towards a Fully Integrated Accelerator on a Chip: Dielectric Laser Acceleration (DLA) From the Source to Relativistic Electrons

laser, electron, emittance, simulation

2520

K.P. Wootton, R.J. England, S.G. Tantawi
SLAC, Menlo Park, California, USA
R.W. Aßmann, I. Hartl, W. Kuropka, F. Mayet, A. Rühl
DESY, Hamburg, Germany
D.S. Black, R.L. Byer, H. Deng, S. Fan, J.S. Harris, T.W. Hughes, N. Sapra, O. Solgaard, J. Vuckovic
Stanford University, Stanford, California, USA
B.M. Cowan
Tech-X, Boulder, Colorado, USA
T. Egenolf, U. Niedermayer
TEMF, TU Darmstadt, Darmstadt, Germany
P. Hommelhoff, A. Li, N. Schönenberger
University of Erlangen-Nuremberg, Erlangen, Germany
J. Illmer, J.C. McNeur, A.K. Mittelbach, A.D. Tafel
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
R. Ischebeck, L. Rivkin
PSI, Villigen PSI, Switzerland
F.X. Kärtner
MIT, Cambridge, Massachusetts, USA
F.X. Kärtner
CFEL, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
Y.J. Lee, M. Qi
Purdue University, West Lafayette, Indiana, USA
P. Musumeci
UCLA, Los Angeles, California, USA
L. Rivkin
EPFL, Lausanne, Switzerland

Funding: This work was supported by the U.S. Department of Energy, Office of Science, under Contract no. DE-AC02-76SF00515, and by the Gordon and Betty Moore Foundation under grant GBMF4744 (Accelerator on a Chip).
Dielectric laser acceleration of electrons has recently been demonstrated with significantly higher accelerating gradients than other structure-based linear accelerators. Towards the development of an integrated 1 MeV electron accelerator based on dielectric laser accelerator technologies, development in several relevant technologies is needed. In this work, recent developments on electron sources, bunching, accelerating, focussing, deflecting and laser coupling structures are reported. With an eye to the near future, components required for a 1 MeV kinetic energy tabletop accelerator producing sub-femtosecond electron bunches are outlined.

Slides WEYB1 [12.774 MB]

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WEPAB123

A Phase Matching, Adiabatic Accelerator

electron, laser, plasma, 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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WEPAB125

Crossbar H-Mode Drift-Tube Linac Design With Alternative Phase Focusing for Muon Linac

cavity, linac, emittance, dipole

2868

M. Otani, K. Futatsukawa
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
S.S. Kurennoy
LANL, Los Alamos, New Mexico, USA

Funding: This work was supported by JSPS KAKENHI Grant Number 15H03666.
A crossbar H-mode (CH) drift-tube linac (DTL) is one of alternatives for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. In this poster, dynamics and cavity designs with computer calculations will be presented.

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WEPAB132

Research Program and Recent Results at the Argonne Wakefield Accelerator Facility (AWA)

wakefield, experiment, electron, emittance

2885

M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, Q. Gao, G. Ha, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.Q. Qiu, J.H. Shao, Y.R. Wang, C. Whiteford, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
Q. Gao, L.M. Zheng
TUB, Beijing, People's Republic of China
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
N.R. Neveu
IIT, Chicago, Illinois, USA
Y.R. Wang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357
We give an overview of the research program at the Argonne Wakefield Accelerator Facility (AWA), including some highlights of recent experiments. The AWA facility is dedicated to the study of beam physics and the development of technology for future particle accelerators. Two independent electron linacs are used to study wakefield acceleration: 70 MeV high charge electron bunches of up to 100 nC are used to drive wakefields, which can be probed by bunches originating from the same linac or from the 15 MeV linac. Recent Two-Beam-Acceleration (TBA) experiments operating at 11.7 GHz reached accelerating gradients of up to 150 MV/m. No indication of witness beam quality degradation was observed, and bunch charge was preserved during the acceleration process. Two identical TBA setups were used in series in order to demonstrate staging capabilities. Dielectric loaded structures operating at 26 GHz are also used in TBA experiments. Another main thrust of the research program consists of exploring and developing techniques to manipulate the phase space of electron bunches. These efforts include bunch shaping and the exchange of emittances in the transverse and the longitudinal phase spaces

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WEPVA001

Electron Injector for Multi-Stage Laser-Driven Plasma Accelerators

electron, laser, plasma, simulation

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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WEPVA002

Simulations of DLA Grating Structures in the Frequency Domain

laser, simulation, electron, cavity

3247

T. Egenolf, O. Boine-Frankenheim, U. Niedermayer
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim
GSI, Darmstadt, Germany

Dielectric laser accelerators (DLA) driven by ultrashort laser pulses can reach orders of magnitude larger gradients than contemporary RF electron accelerators. A new implemented field solver based on the finite element method in the frequency domain allows the calculation of the structure constant, i.e. the ratio of energy gain to laser peak amplitude. We present the maximization of this ratio as a parameter study looking at a single grating period only. Based on this optimized shape the entire design of a beta-matched grating is completed in an iterative process. The period length of a beta-matched grating increases due to the increasing velocity of the electron when a subrelativistic beam is accelerated. The determination of the optimal length of each grating period thus requires the knowledge of the energy gain within all so far crossed periods. Furthermore, we outline to reverse the excitation in the presented solver for beam coupling impedance calculations and an estimation of the beam loading intensity limit.

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WEPVA003

Designing a Dielectric Laser Accelerator on a Chip

laser, electron, bunching, synchrotron

3250

U. Niedermayer, O. Boine-Frankenheim, T. Egenolf
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work is funded by the Gordon and Betty Moore Foundation (Grant GBMF4744 to Stanford) and the German Federal Ministry of Science and Education (Grant FKZ:05K16RDB).
Dielectric Laser Acceleration (DLA) achieves gradients of more than 1GeV/m, which are among the highest in non-plasma accelerators. The long-term goal of the ACHIP collaboration* is to provide relativistic (>1 MeV) electrons by means of a laser driven microchip accelerator. Examples of slightly resonant dielectric structures showing gradients in the range of 70% of the incident laser field (1 GV/m) for electrons with β=0.32 and 200% for β=0.91 are presented. We demonstrate the bunching and acceleration of low energy electrons in dedicated ballistic buncher and velocity matched grating structures. However, the design gradient of 500 MeV/m leads to rapid defocusing. Therefore we present a scheme to bunch the beam in stages, which does not only reduce the energy spread, but also the transverse defocusing. The designs are made with a dedicated homemade 6D particle tracking code.
* https://achip.stanford.edu

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WEPVA004

Simulation of an Electromagnetic Field Excitation by a THz-pulse and Acceleration of an Electron Bunch in a Dielectric-loaded AXSIS Linac

linac, electron, injection, simulation

3253

K. Galaydych, R.W. Aßmann, U. Dorda, B. Marchetti, G. Vashchenko, I. Zagorodnov
DESY, Hamburg, Germany

Funding: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 609920
The Attosecond X-ray Science: Imaging and Spectroscopy (AXSIS) experiment at DESY will use a dielectric loaded waveguide to accelerate electron bunches up to 15 MeV. Such a linac will be powered by a narrowband multicycle THz-pulse with a central frequency of 300 GHz. In this paper we focus on the reflection of the excited field at a pinhole, on the optimization of the bunch injection time and on the bunch dynamics in the acceleration process. The linac excitation by the THz-pulse and the bunch acceleration in the excited field are investigated using CST and ECHO simulations.

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WEPVA005

Simulation of a Many Period Dielectric Grating-based Electron Accelerator

laser, electron, simulation, emittance

3256

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

Funding: GBMF - Gordon and Betty Moore Foundation
Dielectric laser driven particle accelerators have become a research area of major interest due to the high acceleration gradients achievable. Those are mainly attributed to the high damage thresholds of dielectrics at optical frequencies. Simulations of these structures are usually computed with Particle-In-Cell (PIC) codes. Their accuracy and self consistency comes with a major drawback of high computation costs. Computation of structures consistent of hundreds to thousands of periods are only viable with High Performance Computing clusters. In this proceeding a compromise of CST* PIC simulations combined with a transfer function model is presented to simulate relativistic electron accelerators for particle energies up to the GeV regime or higher. In addition a simplified example accelerator design is investigated and the required electron bunch parameters from a sub-relativistic source are computed.
*CST - Computer Simulation Technology, available from www.
cst.com.

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WEPVA006

A Concept for Phase-Synchronous Acceleration of Microbunch Trains in DLA Structures at SINBAD

laser, electron, simulation, linac

3260

F. Mayet, R.W. Aßmann, J. Bödewadt, R. Brinkmann, U. Dorda, W. Kuropka, C. Lechner, B. Marchetti, J. Zhu
DESY, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
J. Zhu
University of Hamburg, Hamburg, Germany

Funding: GBMF - Gordon and Betty Moore Foundation
The concept of dielectric laser accelerators (DLA) has gained increasing attention in accelerator research, because of the high achievable acceleration gradients (~GeV/m). This is due to the high damage threshold of dielectrics at optical frequencies. In the context of the Accelerator on a Chip International Program (ACHIP) we plan to inject electron bunches into a laser-illuminated dielectric grating structure. At a laser wavelength of 2 micro-meter the accelerating bucket is <1.5 fs. This requires both ultra-short bunches and highly stable laser to electron phase. We propose a scheme with intrinsic laser to electron synchronization and describe a possible implementation at the SINBAD facility (DESY). Prior to injection, the electron bunch is conditioned by interaction with an external laser field in an undulator. This generates a sinusoidal energy modulation that is transformed into periodic microbunches in a subsequent chicane. The phase synchronization is achieved by driving both the modulation process and the DLA with the same laser pulse. This allows scanning the electron bunch to laser phase and will show the dependence of the acceleration process on this delay.

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WEPVA011

Development of a Laser Driven Dielectric Accelerator for Radiobiology Research

electron, laser, experiment, simulation

3272

K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Z. Chen, H. Okamoto
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was supported by KAKENHI, (Grant-in-Aid for Scientific Research) Grant Number 15H03595 and partly supported by NIMS Nanofabrication Platform in Nanotechnology Platform Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
A laser-driven dielectric accelerator below 1 MeV is under development for applying a sub-micron size electron-beam to radiobiological research. Simulations of the electric field and electron trajectories in the proximity of the dielectric structure (transmission grating) were performed in order to fix parameters of the demonstration experiment. Serious deflection of electron beam towards the grating limited the injection phase as well as the height from the structure. The energy gain of 50-keV electron was estimated to be 1 keV in 30-micron length at the optimum condition. Transmission gratings for the experiment were fabricated by using facilities of the NIMS Nanofabrication Platform. In addition to the acceleration experiment using the simple grating, a resonator type accelerator structure was designed for exciting the acceleration field by a moderately small laser.

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WEPVA012

Laser Proton Accelerator with Improved Repeatability at Peking University

laser, target, proton, plasma

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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WEPVA016

Dielectric Laser Accelerator Investigation, Setup Substrate Manufacturing and Investigation of Effects of Laser Induced Electromigration RF Cavity Breakdown Influences

laser, electron, vacuum, controls

3286

M. Hamberg, M. Jacewicz, J. Ögren
Uppsala University, Uppsala, Sweden
M. Karlsson, E. Vargas Catalan
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
M. Kuittinen, I. Vartiainen
UEF, Joensuu, Finland

Funding: I thank Stockholm Uppsala centre for FEL research for funding.
Dielectric laser acceleration (DLA) where the high electric fields in lasers are used to accelerate electrons next to nanofabricated dielectric structures has recently been proven in proof of concept studies. In this paper I describe investigations setup and substrate manufacturing. Additionally we describe using the setup for evaluating RF structure breakdown due to laser induced electromigration occurences.

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WEPVA018

Drive-Witness Acceleration Scheme Based on Corrugated Dielectric mm-Scale Capillary

wakefield, laser, electron, experiment

3292

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

Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179.
In this paper, we investigate a corrugated mm-scale capillary as a compact accelerating structure in a drive-witness acceleration scheme, and suggest a methodology to measure acceleration of a witness bunch. Two typical measurements and the energy gain in a witness bunch as a function of the distance between bunches are discussed. A corrugated capillary is considered as an accelerator/decelerator with an adjustable wakefield pattern depending on a transverse beam position.

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WEPVA019

Group Velocity Matching in Dielectric-Lined Waveguides and its Role in Electron-THz Interaction

electron, simulation, accelerating-gradient, interface

3296

A.L. Healy, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
D.M. Graham
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
S.P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Terahertz(THz)-driven dielectric-lined waveguides have applications in electron manipulation, particularly acceleration, as the use of dielectric allows for phase velocities below the speed of light. However matching a single frequency to the correct velocity does not maximise electron-THz interaction; waveguide dispersion typically results in an unmatched group velocity and so the pulse envelope of a short THz pulse changes along the length of the structure. This reduces field amplitude and therefore accelerating gradient as the envelope propagates at a different velocity to the electron. Presented here is an analysis of the effect of waveguide dispersion on THz-electron interaction and its influence on structure dimensions and choice of THz pulse generation. This effect on net acceleration is demonstrated via an example of a structure excited by a single-cycle THz pulse, with a comparison of multi-cycle, lower intensity THz pulses on net acceleration.

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WEPVA022

RECENT TWO-BEAM ACCELERATION ACTIVITIES AT ARGONNE WAKEFIELD ACCELERATOR FACILITY

experiment, accelerating-gradient, wakefield, impedance

3305

J.H. Shao, S.P. Antipov, M.E. Conde, W. Gai, Q. Gao, G. Ha, W. Liu, N.R. Neveu, J.G. Power, Y.R. Wang, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
J. Shi, D. Wang
TUB, Beijing, People's Republic of China

The Two-Beam Acceleration (TBA) is a modified approach to the structure-based wakefield acceleration which may meet the luminosity, efficiency, and cost requirement of a future linear collider. Recently, various TBA experiments have been carried out at the Argonne Wakefield Accelerator Facility (AWA). With X-band metallic power extractors and accelerators, a 70 MeV/m average accelerating gradient has been demonstrated in two stages while a 150 MeV/m gradient as well as 300 MW extracted power have been achieved in a single stage. In addition, low cost K-band dielectric power extractor and accelerator have also been developed. The preliminary results show power extraction of 55 MW and an average accelerating gradient of 28 MeV/m.

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WEPVA054

Study of The New Return Yoke for The Upgraded Superconducting Cyclotron of INFN-LNS

extraction, ion, cyclotron, experiment

3381

A. Calanna, L. Allegra, L. Calabretta, G. Costa, G. D'Agostino, G. Gallo, D. Rifuggiato, A.D. Russo
INFN/LNS, Catania, Italy
G. D'Agostino
Universita Degli Studi Di Catania, Catania, Italy

The LNS Superconducting Cyclotron (CS) has been working for 20 years making available a wide range of ions and energies. Its operational diagram is peculiar and many experiment are performed each year. In the near future a major upgrade is planned. This will allow to overcome the major limitation of the CS, which is the beam power limited at 100 W. In the new version of the CS, the extracted beam power will be increased up to a factor 100. This improvement will be reached adding a new extraction line dedicated to a specific set of light ions and energies extracted by stripping. The new design could affect the beam dynamics strongly. Indeed, the iron yoke penetrations don't respect the three folds symmetry of our cyclotron. This inhomogeneity produces unwanted field harmonics, which have to be reduced as much as possible to avoid beam precession or second order effects. Here the study accomplished to minimize the perturbation of the non-three fold field symmetry using the current sheet approximation (CSA) is presented, along with the state-of-art configuration of the updated cyclotron

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THPAB014

An Adaptive Mesh-Based Method for the Efficient Simulation of LSC-Driven Microbunching Gain in FEL Applications

electron, FEL, bunching, simulation

3720

Ph. Amstutz
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
M. Vogt
DESY, Hamburg, Germany

Electron beams with high peak current as they are required for the operation of free-electron lasers (FELs) are often generated by means of a series of magnetic bunch compressors. In conjunction with a collective coherent force, e.g. longitudinal space-charge (LSC), bunch compressors can possibly cause a wavelength dependent amplification of initial density inhomogeneities, potentially to an extent detrimental to the operation of the FEL. A common model, consisting of LSC, acceleration (kicks), and magnetic chicanes (drift-type maps), is governed by a time-discrete Vlasov-Poisson system. Such systems have been successfully simulated using mesh based representations of the phase space density (PSD) and the method of characteristics for the update step. However, for the irregular and exotic PSDs, prevalent in FEL applications, a homogeneous high resolution discretization on a naive rectangular mesh can be prohibitively wasteful. Here we present an approach based on adaptive tree refinement that addresses the complexity of the PSDs and allows for the efficient simulation of LSC-driven micro-bunching in FELs.

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THPAB024

Emittance Growth at Charge-Exchanging Multi-Turn Injection in KURRI FFAG

injection, emittance, scattering, simulation

3747

T. Uesugi, Y. Ishi, Y. Kuriyama, Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor institute (KURRI), rapid beam loss of factor 100 is observed right after the injection. In the synchrotron, charge-exchanging multi-turn injection is adopted with a stripping foil located on the closed orbit of the injection energy. No bump orbit system is used and the injected beams escape from the foil according to the closed-orbit shift by acceleration. The particles hit the foil many times and that is why the emittance grows up during the injection. In this paper, simulation studies are done to estimate the emittance growth and beam losses. The scattering effect at the foil is modeled by GEANT4.

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THPAB025

Simulation Studies of Transverse Beam Instabilities and Measures Beyond 1 MW Beam Power in the 3-GeV RCS of J-PARC

impedance, simulation, injection, extraction

3750

P.K. Saha, H. Hotchi, Y. Shobuda
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The transverse impedance of the extraction kicker magnets is a significant beam instability source in the 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex). The systematic simulation studies for beam instability by including the space charge effect has been done by using the ORBIT code. The simulation results are well reproduced in the corresponding measurements. The designed 1 MW beam power has recently been accomplished by keeping sextuple magnets off in order to stabilize the beam by utilizing the large lattice chromaticity throughout the entire acceleration period. The RCS simultaneously delivers extracted beam to the MLF (Material and Life Science Experimental Facility) and the MR (Main Ring). In order to ensure 1 MW beam power at the MLF even when RCS beam sharing to the MR is twice increased as well as when a second target station is constructed at the MLF, a beam power of 1.5 MW has to be realized in the RCS. However, the simulation shows that beyond 1 MW the beam is unstable even if no chromaticity is corrected. A reduction of the kicker impedance by at least a half is required in order to achieve 1.5 MW beam power in the RCS.

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THPAB034

Generation of Short Intense Heavy-Ion Pulses in HIAF

ion, injection, heavy-ion, cavity

3774

D.Y. Yin, H. Du, L.J. Mao, G.D. Shen, J.W. Xia, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

The HIAF is a new accelerator complex under design at IMP to provide intense primary and radioactive ion beams for nuclear physics, atomic physics, high energy density physics and other applications. As a key part of HIAF, the Booster Ring (BRing) is designed to accumulate and accelerate heavy ion beams provided by iLinac up to high intensity and energy. The high quality, well focused, strongly bunched intense Uranium beam (U³⁴⁺) with high energy and high intensity of 10¹¹ will open a new area for the HED physics research in laboratory. Based on the beam parameters of 238U³⁴⁺ proposed by the BRing, the two critical issues of producing short bunch with high beam intensity are studied. One is efficiency of adiabatic capture which can be a necessary prerequisite to ensure the beam intensity, and the other one is bunch compression in longitudinal which is an effective way of producing short pulse duration bunch. In this article, the analytical calculations and tracking simulations are described, the capture efficiency and possible bunch length under the action of planning RF system are presented

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THPIK059

Experimental Study on PM-AM Method in Pulse Compression System

LLRF, klystron, experiment, cavity

4230

P. Wang, H.B. Chen, C. Cheng, M.M. Peng, J. Shi, X.W. Wu, J. Yang, H. Zha
TUB, Beijing, People's Republic of China

We experimentally demonstrate the PM-AM method (Phase Modulation to Amplitude Modulation) at the S-band high power test stand, which consists of two S-band klystrons, a SLED type pulse compressor and two high power stainless steel RF loads, in Tsinghua University. A LLRF (low level RF) system has been developed to modulate the phases of the two klystrons in real time such that pulse compressor could generate a flat output pulse. Experimental results presents that the efficiency of the pulse compression system is 45% and the power gain is 2.9.

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THPIK110

RF Cavity Design for a Low Cost 1 MeV Proton Source

cavity, proton, simulation, impedance

4355

D. Soriano Guillén, R. Seviour
University of Huddersfield, Huddersfield, United Kingdom
S. Hunt
Alceli Accelerator Technology Ltd., Huddersfield, United Kingdom

In this paper we present the design for a low-cost RF cavity capable of accelerating protons from 100 keV to 1 MeV. The system is designed to meet the specifications from the proposed Alceli LTD medical proton therapy linac, to deliver a 1 nA proton beam current with a 1 kHz repetition rate. We present a design of an RF normal conducting (NC) re-entrant Cu cavity operating at 40 MHz consisting of a coupled two cavity system, both driven by a single Marx generator. The choice of such a low operating frequency for the cavity system enables us to use a relatively low-cost cost Marx Generator as the RF source. Marx generators work in a similar fashion to a Cockcroft-Walton accelerator (without the expensive components), creating a high-voltage pulse by charging a number of capacitors relatively slowly in parallel, then rapidly discharging in series, via spark gaps. Marx generators can deliver 2.5 GW, 1 ns pulses, with rise times of 200 ps, and (relatively) low jitter.

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THPVA017

Integer Spin Resonance Crossing With Preserving Beam Polarization on VEPP-4M

polarization, resonance, solenoid, experiment

4451

A.K. Barladyan, A.Yu. Barnyakov, S.A. Glukhov, S.E. Karnaev, E.B. Levichev, S.A. Nikitin, I.B. Nikolaev, I.N. Okunev, P.A. Piminov, A.G. Shamov, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia

The method to preserve the electron beam polarization on the VEPP-4M storage ring during acceleration with crossing the integer spin resonance energy E=1763 MeV is described. It is based on the use of the non-compensated longitudinal magnetic field of the KEDR detector. This method has been successfully applied for the needs of the R measurement experiment.

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THPVA072

Travelling Laser Focus System for the Particles Acceleration

laser, radiation, emittance, photon

4613

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

We describe the result of the wake-fields calculation in a device for acceleration of particles in the micro-structures illuminated by the swept laser bust. Calculations carried with help of FlexPDE code.

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THPVA082

Multi-Energy Trial Operation of the HIT Medical Synchrotron: Accelerator Model and Data Supply

ion, synchrotron, extraction, controls

4644

M. Galonska, E. Feldmeier, Th. Haberer, A. Peters, C. Schömers
HIT, Heidelberg, Germany

At the Heidelberg ion beam therapy center (HIT) cancer patients are treated with the raster-scanning dose delivery method of heavy ion pencil beams. The beams are provided by a synchrotron which allows for a variation of the ion penetration depth by changing the ion beam energy for each synchrotron cycle. In order to change the beam energy within one synchrotron cycle the accelerator model and data supply model within the control system have been extended extensively. In this first data supply model beam re-acceleration or deceleration between two arbitrary extraction energies is defined. The model defines an additional transition phase, i.e. current/set value patterns between extraction and the re-acceleration yet giving the possibility of setting the beam properties suitable for further acceleration/deceleration. This includes the dipoles, correctors, quadrupoles, sextupoles, KO-Exciter (spill break), and RF. This allowed for the survey and optimisation of the beam properties including possible beam losses of the re-accelerated, transversally blown up beam for arbitrary energy levels.

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THPVA083

First Tests of a Re-accelerated Beam at Heidelberg Ion-Beam Therapy Centre (HIT)

synchrotron, extraction, ion, operation

4647

C. Schömers, E. Feldmeier, M. Galonska, Th. Haberer, J.T. Horn, A. Peters
HIT, Heidelberg, Germany

In the active raster scanning method performed at HIT since 2009, tumors are irradiated slice-by-slice by changing the extraction energy. The synchrotron provides a library of 255 different extraction-energy levels per ion type, according to the aimed penetration depth. So far, a new synchrotron cycle is started for each iso-energy-slice resulting in a non-optimal duty cycle. In order to reduce treatment time and to increase the number of patients treated per day, synchrotron cycles with several extraction flattops on different energy levels are planned. After completing one iso-energy-slice, remaining particles will be reaccelerated to the adjacent level. As a first test a new data supply model generating patterns for power supplies and RF devices with two different extraction flattops has been implemented recently. The properties of the reaccelerated beam are now under detailed examination. The reaccelerated beam was successfully extracted and guided to the experimental area. Ionization chambers along the beam line clearly show two spills on two different extraction flattops. The desired change of beam energy has been verified by range measurements in a water column.

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THPVA133

HEATHER - HElium Ion Accelerator for RadioTHERapy

ion, proton, resonance, injection

4768

J. Taylor, T.R. Edgecock
University of Huddersfield, Huddersfield, United Kingdom
S. Green
University Birmingham, Birmingham, United Kingdom
C. Johnstone
Fermilab, Batavia, Illinois, USA

A non-scaling fixed field alternating gradient (nsFFAG) accelerator is being designed for helium ion therapy. This facility will consist of 2 superconducting rings, treating with helium ions (He²⁺ ) and image with hydrogen ions (H + 2 ). Currently only carbon ions are used to treat cancer, yet there is an increasing interest in the use of lighter ions for therapy. Lighter ions have reduced dose tail beyond the tumour compared to carbon, caused by low Z secondary particles produced via inelastic nuclear reactions. An FFAG approach for helium therapy has never been previously considered. Having demonstrated isochronous acceleration from 0.5 MeV to 900 MeV, we now demonstrate the survival of a realistic beam across both stages.

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