LINAC2018 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MO2A03	Technology Developments for ELI-NP Gamma Beam System	laser, gun, linac, LLRF	13
	L. Piersanti, D. Alesini, A. Battisti, M. Bellaveglia, S. Bini, F. Cardelli, R.D. Di Raddo, A. Falone, A. Gallo, V.L. Lollo, L. Pellegrino, S. Pioli, S. Tomassini, A. Variola INFN/LNF, Frascati (Roma), Italy N. Beaugerard SEIV, Mérignac, France K. Cassou, D. Douillet, K. Dupraz, T. Le Barillec, A. Martens, C.F. Ndiaye, Y. Peinaud, Z.F. Zomer LAL, Orsay, France L. Ficcadenti, A. Mostacci, L. Palumbo, V. Pettinacci INFN-Roma, Roma, Italy M. Migliorati INFN-Roma1, Rome, Italy D.T. Palmer, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy H. Rocipon ALSYOM, Argebteuil, France
	ELI-NP gamma beam system (GBS) is a linac based gamma-source in construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy, from 0.2 to 19.5 MeV, and with intensity and brilliance beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and an intense laser pulse at 100 Hz repetition rate. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation and laser recirculation at the interaction point. In this paper, the main technological developments carried out by the EuroGammaS consortium for the generation of the ELI-NP gamma beam will be described with a special emphasis on the electron linac technology, such as: RF-gun and C-band accelerating structures design fabrication and tests; low level RF (LLRF) and synchronization systems specifications and development. Finally, the laser recirculation apparatus design is briefly described and first results reported.
	Slides MO2A03 [9.121 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A03
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MO2A04	Compact SRF Linac for High Brilliance Inverse Compton Scattering Light Source	laser, brilliance, emittance, gun	19
	K.E. Deitrick, J.R. Delayen, G.A. Krafft, B. Terzić ODU, Norfolk, Virginia, USA J.R. Delayen, G.A. Krafft JLab, Newport News, Virginia, USA
	New designs for compact SRF linacs can produce micron-size electron beams. These can can be used for inverse Compton scattering light sources of exceptional flux and brilliance.
	Slides MO2A04 [1.717 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A04
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO005	Commissioning of the Normal Conducting Cavities for LEReC Project	cavity, booster, MMI, vacuum	44
	B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, A. Zaltsman BNL, Upton, Long Island, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is designed, and is currently under commissioning at BNL. The linac of LEReC consists of a DC photoemission gun, a 704 MHz superconducting radio frequency (SRF) booster cavity, a three-cell 2.1 GHz third harmonic cavity for RF curvature correction, a single-cell 704 MHz cavity for energy de-chirping and a 704 MHz deflecting cavity for diagnostic line. In this paper, we present the commissioning of three normal conducting cavities mentioned above.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO005
About •	paper received ※ 14 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO007	The Developing of the Beam Injection Section with Laser Source and S-Band Electron RF Gun for SuperKEKB Project	laser, gun, MMI, emittance	50
	X. Zhou, Y. Ogawa, M. Yoshida, R. Zhang KEK, Ibaraki, Japan
	For the beam injection at Linac Accelerator of the SuperKEKB project, the s-band RF gun needs to provide low-emittance high-charge electron bunches. An ultrashort high energy solid laser driving a cathode in a quasi-travelling side-coupled RF gun were developed. A Yb fiber and Nd:YAG hybrid laser amplify system is start with 114.24 MHz oscillator that synchronized from accelerator. Two beam lines with the 25Hz, ~20ps, and sub-mJ Ultraviolet pulses were generated to RF gun. Ir5Ce has long lifetime and quantum efficiency QE that was employed to cathode. The RF gun has two side coupled cavities on same axis can realize quasi-traveling wave, which is suitable for the high charge and low emittance beam generation. Now, great progress has been made to make the RF gun function well. For the Phase II commissioning, required charge and emittance were achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO007
About •	paper received ※ 05 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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MOPO008	The RF Gun Adopting the Dielectric Assist Accelerating Structure	cavity, cathode, emittance, gun	54
	S. Mori, D. Satoh, M. Yoshida KEK, Ibaraki, Japan
	We apply the dielectric assist accelerating (DAA) structure to the RF gun, which is a candidate for a high average current and high brightness electron source. The DAA structure consists of ultralow-loss dielectric cylinders and disks which are periodically arranged in a metallic enclosure. Due to the high quality factor and the high shunt impedance of the DAA cavity, the RF gun adopting the DAA cavity can be a high-duty electron beam source at room temperature. We provide design work for RF gun adopting the DAA structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO008
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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MOPO009	ELI-NP Gamma Beam System - Current Project Status	laser, linac, gun, experiment	59
	P.S. Tracz IFIN-HH, Bucharest - Magurele, Romania
	The Gamma Beam System at the ELI-NP under construction in Magurele/Bucharest Romania, aims at producing high brilliance gamma-rays based on the laser Compton back-scattering, up to 3.5 and 19.5 MeV out of two interaction chambers. The design of warm RF electron linac is optimized to meet the unique source specification i.e. high brilliance, small relative bandwidth, tunable energy, and high spectral density. Together with technological development in field of high energy/high quality lasers it will open new opportunities for nuclear physics research in fields like nuclear photonics, nuclear astrophysics, photo-fission, and production of exotic nuclei, applications in industry, medicine, and space science. S-band laser driven RF photo-gun and two accelerating structures constitute the injector. The beam is then accelerated by C-band linac up to 350MeV (low energy linac), and up to 720MeV (high energy linac). The GBS was designed and is being constructed by the EuroGammaS - a consortium of European academic and research institutions and industrial partners. This paper gives an overview of the facility, describes the main linac systems and summarizes the project status.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO009
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO010	JINR Photocathode Research: Status and Plans	cathode, laser, gun, scattering	62
	M.A. Nozdrin, N. Balalykin, J. Huran, V.F. Minashkin, G. Shirkov JINR, Dubna, Moscow Region, Russia E. Gacheva, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia J. Huran Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
	Photocathode research in the frame of the "transmission" photocathode conception (backside illuminated cathode based on a quartz/sapphire plate or a metal mesh which is a substrate for thin film made of a photomaterial) is being conducted in the Veksler and Baldin Laboratory of High Energy physics (LHEP) of the Joint Institute for Nuclear Research (JINR). Status of the 30-kev DC Photogun test bench and recent results of the extremely thin carbon film based cathodes research are described. Progress in the full-scale photoinjector prototype (max electron energy of 400 keV) is given. Startup of the photoinjector was performed, 70 keV electrons were extracted (650 pC).
	Poster MOPO010 [1.564 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO010
About •	paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO016	Narrow-Band Terahertz Generation from Beam Pipe with Helix Wires	radiation, wakefield, simulation, impedance	65
	D. Wang TUB, Beijing, People’s Republic of China
	We studied through analysis and numerical simulations the use of a relativistic electron bunch to drive a metallic beam pipe with helix wire inside, for the purpose of gen-erating narrow-band terahertz radiation. we have shown that the frequency is related to the radius of the pipe and that of the wire, thus one can generate a narrow-band radiation pulse with frequency tunable through this scheme with different pipes and wires. The total energy of a few milli-Joules. The pulse length tends to be on the order of hundreds of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp. wangdan2016@mail.tsinghua.edu.cn yanlx@mail.tsinghua.edu.cn
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO016
About •	paper received ※ 12 September 2018 paper accepted ※ 15 January 2019 issue date ※ 18 January 2019
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MOPO018	Development of an Improved Capture Section for the S-DALINAC Injector*	cavity, linac, simulation, gun	68
	S. Weih, M. Arnold, J. Enders, N. Pietralla TU Darmstadt, Darmstadt, Germany D.B. Bazyl, H. De Gersem, W.F.O. Müller TEMF, TU Darmstadt, Darmstadt, Germany
	For the injector of the superconducting Darmstadt electron linear accelerator S-DALINAC, the design of a new capture cavity was recently completed. This beta-reduced structure will optimize the capture of low-energy electron bunches from the gun section and therefore improve the longitudinal beam quality of the injector beam, as simulations have shown. The existing cryomodule of the injector has to be modified for the installation of the new cavity. These modifications include adaptions of the tuner frame as well as modifications of other surrounding parts. To improve the diagnostics in the low-energy section, an energy-spread measurement setup is currently also under development. In this contribution the cryomodule modifications as well as simulation results for the longitudinal beam dynamics are presented. *Work supported by DFG through GRK 2128 "AccelencE"
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO018
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO020	Beam Dynamics Studies and Instrumentation Tests for Bunch Length Measurements at CLEAR	experiment, gun, simulation, radiation	74
	L. Garolfi, M. Bergamaschi, R. Corsini, A. Curcio, S. Döbert, W. Farabolini, D. Gamba, I. Gorgisyan CERN, Geneva, Switzerland C. Bruni, P. Lepercq, H. Purwar, C. Vallerand LAL, Orsay, France W. Farabolini CEA/DSM/IRFU, France
	A new CERN Linear Electron Accelerator for Research (named CLEAR) has been installed as a general-purpose user facility to study novel accelerating techniques, high-gradient structures, instrumentation and irradiation experiments. CLEAR is a flexible accelerator that can provide high quality bunched electron beams with a wide range of beam parameters up to an energy of 220 MeV, offering several testing capabilities. Among all the potential applications, novel accelerating techniques, such as plasma acceleration and THz generation are considered. These applications require shorter bunches, down to the 100 fs level. This paper reports on beam dynamics studies and instrumentation tests to establish a bunch length of this order in CLEAR. The short bunches are generated using adiabatic bunching in the first accelerating structure. For bunch length diagnostic CLEAR is equipped with a streak camera and a transverse deflecting cavity. Alternatively a phase-scan of the last accelerating structure could be used as well to estimate the bunch length. The experimental results with respect to these different techniques are presented and compared with simulations.
	Slides MOPO020 [0.864 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO020
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO024	Development of High Power Coherent Terahertz Wave Sources at Lebra 125 MeV Linac in Nihon University	FEL, radiation, linac, undulator	78
	T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, Y. Sumitomo, Y. Takahashi, T. Tanaka LEBRA, Funabashi, Japan H. Ogawa, N. Sei AIST, Tsukuba, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number JP16K17539 and JP16H03912. Research and Development of a high performance electron linac for the generation of FEL, Parametric X-ray Radiation (PXR) and THz waves has been continued at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University as a joint research with KEK and National Institute of Advanced Industrial Science and Technology. The transport systems of the THz wave were installed in the vacuum chamber on the downstream side of the bending magnet of the PXR and FEL beam-line. The CER and the CSR are generated by the bending magnet each of the beam line. In addition, the CTR using thin metal foil is also generated. The average power of the CTR wave was measured approximately 1 mJ/macro-pulse (pulse width 4.5 µs) near the CTR wave beam source point in the frequency range of 0.1 - 2.5 THz. In addition, the energy of the CER as high as 0.2 mJ/macro-pulse were achieved with the experimental room. Furthermore, CER of the generated the FEL beam line can also be guided from the bending magnet on the downstream side of the undulator without disturbing the FEL oscillations. THz transport beam-lines and the characteristics of the THz waves are discussed in this report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO024
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO026	The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac	cavity, controls, coupling, radio-frequency	81
	M. Mohseni Kejani, F. Abbasi Davani Shahid Beheshti University, Tehran, Iran S. Ahmadiannamin ILSF, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran S. Zarei Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
	A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO027	Photocathode Laser Pulse Shaping for Improved Emittance	laser, cathode, gun, emittance	84
	M. Kotur, J. Andersson, J. Björklund Svensson, M. Brandin, F. Curbis, L. Isaksson, F. Lindau, R. Lindvall, E. Mansten, R. Svärd, S. Thorin, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden
	We present a setup for producing and characterizing picosecond ultraviolet laser pulses for use in the MAX IV photocathode electron gun preinjector. Frequency-tripled laser pulses from a commercial laser system are shaped directly in the ultraviolet domain using a Fourier-domain pulse shaper. The pulses were characterized using a transitent grating FROG. We discuss a proposed upgrade of the pulse shaper, as well as its limitations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO027
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO028	Survey and Alignment System of 100 MeV/100 kW Electron Linear Accelerator	quadrupole, target, survey, neutron	87
	O. Bezditko, I.I. Karnaukhov, A.Y. Zelinsky NSC/KIPT, Kharkov, Ukraine
	For successful operation and working of electron linear accelerator of "NEUTRON SOURCE" driver it is necessary that all the acceleration sections, the quadrupole triplets, the quadrupole lenses, the dipole magnets, the scanning magnets and the chicane should be installed in design position according design parameters. Accuracies of all electromagnetic elements installation are 150 mkm for all three rotation freedom. The whole process, fiducialization and developing of survey net, alignment is controlled by laser tracker Leica AT 401.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO028
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO029	Physics design and dynamic simulation of a C-band photocathode electron gun for UEM	gun, emittance, cathode, solenoid	90
	T. Chen, W. Li, Y.J. Pei, Zh. X. Tang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	For discovering structure at atomic scale and getting more details of chemical material and biological tissue, an ultrafast electron microscopy (UEM) has been developed and applied in plenty of subjects and studies. This paper described a C-band photocathode electron gun which will be working at 5712MHz to produce ultrashort electron beams with better dynamic parameters. The RF gun is using coaxial coupler to decrease the size of the gun and keep better symmetry of the field in the photocathode gun so that the beam emittance and energy spread can be reduce a lot. The photocathode rf gun will be a important part of the ultrafast electron microscopy (UEM). Using CST MWS and superfish code to simulate design the gun. After dynamic simulation, the beam parameters as the following: Energy is of 3MeV, Normal emittance of 0.12mm-mrad in boin direction, energy spread is of 5.8·10^-4, which are better enough for an UEM.
	Poster MOPO029 [3.599 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO029
About •	paper received ※ 11 September 2018 paper accepted ※ 22 September 2018 issue date ※ 18 January 2019
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MOPO034	Dielectric Waveguide-Based THz Radiator Study for SwissFEL	experiment, radiation, FEL, GUI	94
	L. Shi, S. Bettoni, M.M. Dehler, E. Ferrari, B. Hermann, R. Ischebeck, F. Marcellini, S. Reiche, V.G. Thominet PSI, Villigen PSI, Switzerland A.K. Mittelbach Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
	Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647 THz pulses have many unique properties in terms of radiation matter interaction. In particular their non-ionizing excitation of phonons in matter makes them a preferred pump for pump-probe studies at free electron lasers. In order to enrich the scientific potentials at SwissFEL (Swiss Free Electron Laser), which can provide ultrashort soft and hard X-ray pulses, we plan to build an economic THz radiator in the range of 1-20 THz by passing the spent electron beam through a dielectric lined tube after the electron beam has generated X-rays. These THz pulses will be transported to the photon user station. Since SwissFEL operates with 2 bunches, serving two beamlines, THz from the first bunch can be used at the user station of the second bunch to allow for pump arrival time before the probe. The core of such a THz generation setup is the dielectric lined tube and the relativistic electron beam. This paper reports on the numerical study of these tubes, in terms of mode structure, energy, pulse length etc, which are essential parameters for the pump-probe experiments. These tubes will be fabricated and tested in the near future in the electron beam line for the soft X-ray of SwissFEL.
	Slides MOPO034 [1.471 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO034
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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MOPO039	Status Update of the Fast Energy Corrector Cavity at FLASH	cavity, laser, coupling, free-electron-laser	112
	S. Pfeiffer, J. Branlard, L. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella DESY, Hamburg, Germany M. Fakhari CFEL, Hamburg, Germany
	Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453. Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.
	Poster MOPO039 [1.884 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039
About •	paper received ※ 13 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO040	Coherent Synchrotron Radiation Monitor for Microbunching Instability in XFEL	radiation, laser, bunching, FEL	115
	J.H. Ko, I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea H.-S. Kang, C. Kim, G. Kim PAL, Pohang, Kyungbuk, Republic of Korea
	The microbunching instability is an important issue in an X-ray Free Electron Laser (XFEL). The intensity of the FEL can be reduced significantly by the microbunching instability so that the laser heater is widely used to reduce it. In the X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL), to directly monitor the microbunching instability, a visible CCD camera was included into the coherent radiation monitor (CRM) which uses a pyroelectric detector. It enabled us to measure the microbunching instability more clearly and optimize the FEL lasing in the PAL-XFEL.
	Slides MOPO040 [1.125 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO040
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO042	Evolutionary Many-objective Optimization Algorithm for Large-bandwidth Free-Electron-Laser Generation	FEL, free-electron-laser, laser, linac	121
	J.W. Yan, H.X. Deng SINAP, Shanghai, People’s Republic of China
	Funding: National Natural Science Foundation of China , the National Key Research and Development Program of China, the Young Elite Scientist Sponsorship Program by CAST and Ten Thousand Talent Program. X-ray free-electron lasers (XFELs) are leading-edge instruments in a wide range of research fields. Besides pursuing narrow bandwidth FEL pulses, the large-bandwidth XFEL pulses are very useful in various spectroscopy experiments, multi-wavelength anomalous diffraction, and X-ray crystallography. Overcompression operation scheme can be utilized to generate electron beams with large energy chirp which is benefit for bandwidth broadening. Recently, an evolutionary many-objective (having four or more objectives) algorithm, NSGA-III, was used to optimize the electron beam parameters in the overcompression including energy chirp, energy spread, current profile, peak current, and projected emittance. In this paper, combining with the Xie’s semianalytical estimate formula, the NSGA-III is utilized to find an optimal working point of linac by optimizing the XFEL pulse properties directly. Start-to-end numerical simulations based on the Shanghai soft X-ray Free-Electron Laser user facility parameters demonstrate that a full bandwidth of 4.75% can be generated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO042
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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MOPO058	Industrial Electron Linear Accelerator R&D in CIAE	gun, radiation, linac, controls	124
	J.H. Yang, Y. Yang, G. Yu, Z.Q. Zeng CIAE, Beijing, People’s Republic of China Z.B. Zhu China Institute of Atomic Energy, Beijing, People’s Republic of China
	Electron linear accelerator(E-LINAC)is a vital accelerator type for accelerator applications, which widely applied in industry, agriculture and medical industry. The paper introduces R&D of industrial E-LINAC in China Institute of Atomic Energy (CIAE) , including electron gun, modulator, accelerating tube, assembling and testing. Based on these R&D results, the GT series for non-destructive testing(NDT) and FZ series for irradiation processing are developed successfully. At present these E-LINACs play important roles in pressure vessel inspection, food preservation, sterilization and material modification, promoting the E-LINACs application as well as economic development in China.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO058
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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MOPO060	Linacs for Industry, Cargo Inspection and Medicine Designed by Moscow University	controls, operation, klystron, radiation	130
	A.N. Ermakov, A.S. Alimov, A.N. Kamanin, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov SINP MSU, Moscow, Russia A.S. Alimov, A.N. Ermakov, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, A.S. Simonov LEA MSU, Moscow, Russia I.V. Shvedunov Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia
	Funding: Work supported in part by Ministry of Education and Science of Russia Grant # RFMEFI58217X0011 The report presents the results of development of applied linear electron accelerators with an energy of up to 10 MeV, performed by the Laboratory of Electron Accelerators MSU. We describe linear accelerators for mobile, stationary and train cargo inspection systems with interlaced energies and pulse repetition rate up to 2 kHz, accelerators for radiography, a sterilization accelerator with beam parameters that are adjustable over a wide range, and an accelerator for a radiotherapy complex.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO060
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO061	Beam Parameters Measurement of C-band 6 MeV Linear Electron Accelerator	gun, controls, factory, klystron	133
	D.S. Yurov, A.S. Alimov, A.N. Ermakov, V.V. Khankin, N.V. Shvedunov, V.I. Shvedunov SINP MSU, Moscow, Russia L. Ovchinnikova Laboratory of Electron Accelerators MSU, Ltd, Physics Department, Lomonosov Moscow State University, Moscow, Russia A.S. Simonov LEA MSU, Moscow, Russia
	The new linear electron accelerator with beam energy varied in the range of 2-6 MeV with dual-energy option has been designed by Laboratory of Electron Accelerators MSU Ltd. Linac is based on compact high gradient stand-ing wave C-band accelerating structure fed by multi-beam klystron and is used in the cargo inspection and cancer therapy complexes. In the report, we present the results of electron beam parameters measurements at special stand.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO061
About •	paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO062	Linear Electron Accelerator for Radiation Technologies with Beam Parameters Varied in a Wide Range	operation, radiation, controls, gun	136
	V.V. Khankin, A.S. Alimov, A.N. Ermakov, A.N. Kamanin, A. Kurilik, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov SINP MSU, Moscow, Russia A. Kurilik LEA MSU, Moscow, Russia I.V. Shvedunov, A.S. Simonov Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia
	We present the overview and beam parameters measurements results as well as the operational experience with the S-band pulsed linear electron accelerator with beam energy in the range of 5-10 MeV and maximum beam power of up to 15 kW. The possibility of adjusting the beam parameters in a wide range, provided by the design and control system of the accelerator, allows to use the accelerator in a wide variety of radiation technologies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO062
About •	paper received ※ 07 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO063	Development of Side-coupled X-band Medical Linear Accelerator for Radiotherapy	cavity, linac, gun, target	139
	Y.S. Lee, Y.W. Choi, G.J. Kim, I.S. Kim, J.I. Kim, S. Kim, J.H. Lee KERI, Changwon, Republic of Korea J.H. Hwang, Y.N. Kang, A.R. Kim, J.N. Kim, T.G. Oh, Y.A. Oh, Y. J. Seol, J.S. Shin The Catholic University of Korea, Seoul, Republic of Korea
	Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging devices such as CT or MRI, so that it is possible to precisely focus high dose radiation on tumor tissues while minimizing the normal tissue damage. In order to place the diagnostic and treatment devices simultaneously in a confined space, constraints related to interference and volume between the subsystems must be considered. To meet these requirements, the size and weight of the LINAC system need to be reduced, which can be achieved by applying X-band technology. For the purpose of use in IMRT based on image guided radiotherapy, we developed a 9.3 GHz X-band medical LINAC using side-coupled structure. The LINAC is designed to have the accelerating field strength of 16.8 MV/m, and the beam current transmission efficiency of 26 % at the end of accelerating cell when the supplied RF power is at 1.7 MW. Therefore, it can accelerate the electron beam up to 6.2 MeV with having about 90 mA beam current. We plan to carry out the performance test using beam diagnostics system and X-ray measurement system, and the details of design and experimental results of LINAC will be described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO063
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO069	Nuclear and Mechanical Basic Design of Target for Mo-99 Production Using High Power Electron Linac	target, photon, neutron, linac	148
	A. Taghibi Khotbeh-Sara, F. Rahmani KNTU, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran H. Khalafi AEOI, Tehran, Iran M. Mohseni Kejani Shahid Beheshti University, Tehran, Iran
	Today providing enough supplies of 99mTc / 99Mo as a high usage radioisotope in diagnostic nuclear medicine for the world demand is a big challenge. One of the proofed ways to access reliable source of this radioisotopes is production using e-LINAC [1]. In this investigation it was tried to find the simple and the optimized design of 99Mo production target based on photoneutron reaction using e-LINAC. Based on the Monte-Carlo calculation for radiation transport and finite element thermal analysis, 9 thin plates of enriched 100Mo was suggested. Equal distance between plates was considered for cooling to prevent target melting. The main target includes only 100Mo in one-stage approach method to increase production rate in compare with two-stage approach [2]. Applying 2.5 m/s for inlet velocity of cooling water provides suitable cooling process with maximum temperature of target about 900 ˚C.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO069
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO070	Construction of the Side-coupled Standing-wave e-Linac	cavity, simulation, linac, coupling	151
	S. Zarei Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran F. Abbasi Shahid Beheshti University, Tehran, Iran M. Bahrami, M. Lamehi IPM, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran
	Due to Iran’s growing need for accelerators in various applications, NSTRI electron linear accelerator project has been defined for medical and inspection applications. This accelerator is a 6 MeV side-coupled standing-wave that operate is π /2 mode in the frequency of 2998.5 MHz. In this paper the construction and measurement results of the tube of this accelerator are presented. The prototype tube was constructed from aluminum and was clamped with bolts. By using a network analyzer, electric and magnetic probes and a side-coupled cavity tuning method and a bead-pull measurement technique, RF measurements were carried out. The resonant frequency and quality factor have been achieved 2998.5 MHz and 7940 respectively . low-energy accelerator, construction of linac, standing-wave linac
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO070
About •	paper received ※ 12 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019
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MOPO073	Coherent Edge Radiation Sources in Linac-Based Infrared Free-Electron Laser Facilities	FEL, radiation, undulator, cavity	154
	N. Sei, H. Ogawa AIST, Tsukuba, Ibaraki, Japan K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, T. Tanaka LEBRA, Funabashi, Japan H. Ohgaki, H. Zen Kyoto University, Kyoto, Japan
	Funding: This study was financially supported by JSPS KAKENHI Grant Number JP16H03912. National Institute of Advanced Industrial Science and Technology has been studied far-infrared coherent radiation at Linac-based infrared free-electron laser (FEL) facilities in col-laboration with Nihon University and Kyoto University. To obtain high FEL gain at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University and at Kyoto Uni-versity Free Electron Laser (KU-FEL), the electron-bunch length is compressed to less than 1 ps in their undulator sections. Short electron bunches are suitable for generating intense coher-ent radiation, and we have already developed some terahertz-wave sources based on the coher-ent synchrotron radiation and the coherent transition radiation [1-3]. However, it was difficult to observe them with sufficient intensity without disturbing the infrared FEL oscillations. Then, we now develop coherent edge radiation emitted from downstream bending magnets in the un-dulator sections. It can be extracted from the undulator sections without disturbing the FEL os-cillations. In this presentation, the observed coherent radiation at LEBRA and KU-FEL will be reported on. [1] N. Sei et al., J. Phys. D: Appl. Phys. 46, (2013) 045104. [2] N. Sei et al., Nucl. Instr. and Meth. A, 832, (2016) 208. [3] N. Sei et al., Jpn. J. Appl. Phys.: 56, (2017) 032401.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO073
About •	paper received ※ 29 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO076	Study on Generation of Variable Polarized Coherent THz Radiation Using a Crossed Undulator	undulator, radiation, polarization, controls	157
	H. Saito, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, K. Takahashi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A variable polarized THz radiation source using a crossed undulator system has been developed at Tohoku University. In this scheme, two coherent undulator radiations from an extremely short electron bunch are used to control the polarization. They are linearly polarized radiations orthogonal to each other. Polarization of superimposed radiation is controlled by adjusting a relative phase between them. A compact planar undulator with seven periods has been designed for an experiment at our facility. The radiation frequency is 2.06 THz for electron beam energy of 22 MeV. The opening angle of the crossed undulator radiation was estimated to be 34 mrad (FWHM). Since the polarization state of the crossed undulator depends on observation angle, its angular dependence was evaluated. It was found that ideal polarization control is realized only in the angle range of 2.5 mrad, which is quite smaller than that of the radiation itself.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO076
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO118	Optimized Design for a Compact Linac with Collinear Absorbing Loads at the Hust FEL-THz	cavity, linac, FEL, radiation	242
	J. Jiang, G. Feng, T. Hu, Y. Lu, X.D. Tu, Y.Q. Xiong HUST, Wuhan, People’s Republic of China Y.J. Pei USTC/NSRL, Hefei, Anhui, People’s Republic of China
	To meet the requirement of miniaturization for high power THz radiation in the field of commercial and civil use, RF Linacs have been applied widely as beam injectors, and the Linac with collinear absorbing loads reveals the potential to achieve a tradeoff between performance and compactness. Under overall consideration of systematic conflicts, optimization choices for such Linacs involving power absorbing ability, accelerating efficiency, as well as beamline length were described in this context. Meanwhile, cold testing has been conducted to verify design parameters for the collinear absorbing loads. Furthermore, elaborated calculation of thermal power loss and integrated helical water channel cooling has been performed for the 14MeV Linac with collinear absorbing loads installed on the HUST FEL-THz, and online experiments demonstrated that both the accelerating efficiency and the water cooling performance fulfilled operation demands.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO118
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO121	Large-Scale Optical Synchronization System of the European XFEL	laser, FEL, timing, experiment	253
	J.M. Müller, M. Felber, T. Kozak, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack DESY, Hamburg, Germany
	At the European XFEL, a facility-wide optical synchronization system providing a femtosecond-stable timing reference at more than 40 end-stations had been developed and installed. The system is based on an ultra-stable, low-noise laser oscillator, whose signals are distributed via actively length-stabilized optical fibers to the different locations across the accelerator and experimental areas. There, it is used to locally re-synchronize radio frequency signals, to precisely measure the arrival time of the electron beam for fast beam-based feedbacks, and to phase-lock optical laser systems for electron bunch generation, beam diagnostics and user pump-probe experiments with femtosecond temporal resolution. In this paper, we present the system’s architecture and discuss design choices to realize an extensible, large-scale synchronization infrastructure for accelerators that meets reliability, maintainability as well as the performance requirements. Furthermore, the latest performance result of an all-optically synchronized laser oscillator is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO121
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO122	European XFEL Cooling and Ventilation Systems	FEL, undulator, photon, controls	257
	J.-P. Jensen DESY, Hamburg, Germany
	The European Free Electron Laser XFEL is operating since 2016. The technical systems for cooling and Ventilation CV were design, built and commissioned by the DESY work package WP34. The CV systems will be described and presented. The water cooling system consists of 3 cooling systems: 30/45 °C LCW for klystron and magnet cooling, 20/30 °C LCW for tunnel rack cooling and 8/14 °C for air conditioning and dehumidification of the air. The ventilation of the tunnels is connected to a series ventilation system from the experimental hall in direction to the injector. The series ventilation of the tunnels saves costs for air treatment with cooling, heating and dehumidification. The tunnel walls are a good heat storage that increases the air temperature stability by a factor of ten. The advantages of this concept will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO122
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TU1A03	Status and Issues (Microphonics, LFD, MPS) with TRIUMF ARIEL e-Linac Commissioning	cavity, linac, TRIUMF, MMI	286
	S.R. Koscielniak, M. Alcorta, F. Ames, E. Chapman, K. Fong, B. Humphries, O.K. Kester, D. Kishi, R.E. Laxdal, Y. Ma, T. Planche, M. Rowe, S.D. Rädel, V.A. Verzilov, Z.Y. Yao TRIUMF, Vancouver, Canada
	The ARIEL electron linac (e-linac) is designed to generate cw beams of up to 30 MeV and 10 mA for delivery to a photo-convertor. Bremsstrahlung induced fission of a production target yields neutron-rich rare isotope beams to be supplied to the ISAC experimental facilities. The beam power will eventually reach 300 kW, and a machine protection system (MPS) with 10 μs rapidity is essential. The e-linac, which adopts 1.3 GHz, 2K SRF technology, is composed of a 10 MeV single-cavity injector cryomodule (EINJ) and a 20 MeV two-cavity accelerator cryomodule (EACA). The latter has vector-sum control of two cavities driven from a single klystron. Beam commissioning of these systems is ongoing since 2016. The magnetic optics and MPS commissioning to 10 MeV is reported herein. Beam has been accelerated up to 25 MeV, and thread-ed to the high energy dump (EHD). A campaign to investigate microphonics driving terms, LN2 disturb-ances, and a ponderomotive instability in the EACA, is underway.
	Slides TU1A03 [9.683 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A03
About •	paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TU1P01	Extreme High Brightness Electron Beam Generation in a Space Charge Regime	cavity, emittance, space-charge, bunching	314
	A. Bacci Istituto Nazionale di Fisica Nucleare, Milano, Italy L. Faillace, M. Rossetti Conti Universita’ degli Studi di Milano & INFN, Milano, Italy
	The generation of ultra-short, low emittance and low energy spread electron bunches is nowadays a critical requirement for accelerators in plasma wave or for femto-second light sources. A new longitudinal compression scheme, based on velocity and ballistic bunching tech-niques in presence of space charge forces, allows to enter in a peculiar regime, so-called laminar bunching (LB). In this regime, the bunch is longitudinally compressed, at the expense of its transverse size, and the over-bunching is forbidden by the laminarity: going to the minimal longi-tudinal dimension the bunch is adiabatically frozen and transversally refocused. Furthermore this technique heats slightly the uncorrelated energy spread resulting in elec-tron distributions that, in case of bending paths, does not require Laser Heater devices.
	Slides TU1P01 [1.720 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1P01
About •	paper received ※ 12 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019
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TUPO001	About the Limits for the Accelerated Beam Current in the LUE-200 Linac of the IREN Facility	klystron, linac, neutron, acceleration	320
	A.P. Sumbaev JINR, Dubna, Moscow Region, Russia A.M. Barnyakov, A.E. Levichev BINP SB RAS, Novosibirsk, Russia
	The beam current loading of the accelerating fields is discussed for the linear accelerator LUE-200 of IREN facility. LUE-200 electron Linac consits of two disk loaded travelling wave accelerating structure with the operating frequency of 2856 MHz and power compression SLED-type system. The limits by the accelerated beam current are defined for different pulse durations of the beam current and RF power. The calculated results are discussed and compared with the measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO001
About •	paper received ※ 12 September 2018 paper accepted ※ 22 January 2019 issue date ※ 18 January 2019
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TUPO002	Electron Gun for 100 MeV / 100 kW Linear Accelerator of Electrons as the Driver of Nuclear Subcritical Assembly Neutron Source	gun, cathode, neutron, controls	323
	M. Moisieienko, O. Bezditko, A. Mytsykov, A.Y. Zelinsky NSC/KIPT, Kharkov, Ukraine
	100 MeV / 100 kW linear electron accelerator of The "neutron source" nuclear subcritical assembly uses the 120 KW triode electron gun as the primary source of electrons. The gun is designed, manufactured and tested at IHEP, Beijing, China. At present, the gun is installed, tested. The maximum impulse current of the gun equal to 2 A. Under design operation, the impulse current of the gun equal to 0.55 A.The report describes the construction of a 120 kV triode electron gun, the results of testing and test operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO002
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO036	Vertical Test Results of Plasma In-situ Cleaning on Low Beta HWR Cavity	plasma, cavity, experiment, SRF	408
	A.D. Wu, H. Guo, Y. He, C.F. Hu, S.C. Huang, C.L. Li, Y.M. Li, X. Liu, F. Pan, Y.K. Song, P.R. Xiong, L. Yang, W.M. Yue, C. Zhang, S.H. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Field emission occurred in SRF cavity is the major limitation to operate at high gradient with stability. The plasma in-situ cleaning for the low beta HWR cavity was carried out to remove the hydrocarbons contaminants on the inner cavity surface. And the vertical test results indicated that the field emission effect was relieved with the increasing of the quench point and emission set-on point. Thus, oxygen active plasma processing can be an effective method to solve the field emission issues for the low beta HWR cavity.
	Slides TUPO036 [1.281 MB]
	Poster TUPO036 [0.672 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO036
About •	paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUPO051	Design Considerations of a Balloon-shaped SSR Superconducting Cavity	cavity, simulation, distributed, superconducting-cavity	448
	H.J. Cha, S.W. Jang, E.-S. Kim, K.R. Kim, S. H. Park, J.Y. Yoon Korea University Sejong Campus, Sejong, Republic of Korea
	A single spoke resonator (SSR, β = 0.51 and f = 325 MHz) is being developed at Korea University. It is well-known that a traditional spoke cavity having flat or round end walls has broad multipacting ranges in acceleration gradient, sometimes including operation region. In general, quite long conditioning time is consumed to overcome such multipacting barriers. In this study, we introduce a balloon-shaped SSR superconducting cavity for the multipacting mitigation due to structural simplicity. The electromagnetic modeling of the SSR was made based on the RF parameter optimization. The simulation results show much narrower multipacting bandwidth, compared to those for the traditional spoke cavity. Mechanical analyses with stiffening structure at maximum allowable working pressures indicate acceptable stresses at the SSR cavity wall. In addition, the resonant frequency shifts due to fabrication and processing for cold tests are predicted and power coupling and tuning mechanism are also investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO051
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO054	Fundamental Studies of Impurity Doping in 1.3 GHz and Higher Frequency SRF Cavities	cavity, niobium, SRF, radio-frequency	458
	J.T. Maniscalco, P.N. Koufalis, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	As the demand for more powerful, more efficient, and smaller superconducting RF accelerators continues to increase, both impurity doping and high-frequency cavities (> 1.3 GHz) have become hot topics for fundamental research because of their potential to significantly decrease surface losses and cost respectively. In this report, we present recent experimental and theoretical results on undoped and nitrogen-doped high-frequency cavities and on alternative doping agents in traditional 1.3 GHz cavities, with a focus on understanding the fundamental science of impurity doping.
	Slides TUPO054 [1.956 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO054
About •	paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO064	Pre-study of CEPC SRF Cavity	cavity, SRF, cryomodule, collider	476
	P. Sha Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People’s Republic of China J. Dai, C. Dong, H.F.S. Feisi, S. Jin, Z.Q. Li, B.Q. Liu, Z.H. Mi, J.Y. Zhai, X.Y. Zhang, H.J. Zheng IHEP, Beijing, People’s Republic of China J.K. Hao, F. Wang PKU, Beijing, People’s Republic of China
	Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400) and National Natural Science Foundation of China (Grant NO.:11505197). CEPC will use 650 MHz cavities for the collider and 1.3 GHz cavities for the Booster. Each booster cryomod-ule contains eight 1.3 GHz 9-cell cavities, which is simi-lar as LCLS-II, E-XFEL and ILC. Each collider cryo-module contains six 650 MHz 2-cell cavities, which is totally new. Therefore, the pre-study mainly focuses on the 650 MHz 2-cell cavity. N-doping and vertical tests of 650 MHz 1-cell and 2-cell cavities have been carried out at IHEP, which have achieved good results. A test cryomodule, which consists of two 650 MHz 2-cell cavities, has also begun as the first step to the full-scale cryomodule.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO064
About •	paper received ※ 31 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO078	Extension of Busch’s Theorem to Particle Beams	emittance, solenoid, experiment, cathode	516
	L. Groening, C. Xiao GSI, Darmstadt, Germany M. Chung UNIST, Ulsan, Republic of Korea
	In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with longitudinal magnetic field. The theorem relates particle angular momentum to the amount of field lines being enclosed by the particle cyclotron motion. Recently it has been extended to accelerated particle beams [Phys. Rev. Accel. Beams 21 014201 (2018)]. This contribution sketches this extension and applies the extended theorem to successfully performed emittance manipulations with electron and ion beams.
	Slides TUPO078 [0.999 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO078
About •	paper received ※ 24 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO090	Electron-beam Matching to Solenoid Magnetic Field in a Klystron	klystron, gun, solenoid, injection	534
	S.J. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea J.H. Hwang, S.-G. Shin POSTECH, Pohang, Kyungbuk, Republic of Korea S.Y. Hyun, D.H. Yu Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea
	Funding: The work was supported by the National R&D Program (grant number: 2016R1A6B2A01016828) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, Korea. High-power klystrons for particle accelerators employ high-perveance electron guns which are usually focused by Solenoid magnets. The electron beam should be optically matched to the downstream magnetic field to prevent the beam from scalloping. The task usually requires a series of computer simulations with many design parameters, and therefore requires extensive(sometimes exhaustive) efforts if not aided by a priori experiences. In order to alleviate the difficulties we have developed a matching procedure which is systematic and reliable. In this article we describe the procedure with an example design of a 400-kV 500-A electron beam with radius 8 - 11 mm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO090
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO092	Beam Dynamics and Collimation Following MAGIX at MESA*	target, simulation, scattering, radiation	540
	B. Ledroit, K. Aulenbacher IKP, Mainz, Germany
	Funding: * Supported by the DFG through GRK 2128 The Mainz Energy-recovering Superconducting Accelerator (MESA) will be an electron accelerator allowing operation in energy-recovery linac (ERL) mode, where beam energy is recovered by decelerating the beam in linac cryomodules and transferring kinetic energy to the RF. The ERL mode provides the opportunity to operate experiments at peak energy with thin targets, combining high luminosities typical for storage rings and high beam brightness typical for linacs. The MESA Internal Gas Target Experiment (MAGIX) aims to operate jet targets at high luminosities with different gases up to Xenon. As scattering effects in the beam rise with the atomic number, investigations on the impact of the target on beam dynamics and beam losses are required for machine safety. The goal of this work is to understand target induced halo, track halo particles through downstream sections and protect the machine with a suitable collimation system and shielding from direct and indirect damage through beam losses and radiation. The present status of the investigations is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO092
About •	paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO097	Design of C-band Electron Linear Accelerator for a Complex of Radiation Therapy	gun, target, radiation, controls	550
	L. Ovchinnikova, V.I. Shvedunov SINP MSU, Moscow, Russia L. Ovchinnikova, V.I. Shvedunov LEA MSU, Moscow, Russia
	Funding: This material is based upon work supported by the Ministry of Education and Science of the Russian Federation, under Grant Agreement No. 14.582.21.0011, Grant Agreement Unique ID RFMEFI58217X0011. The report presents the design of the linear electron accelerator for a complex of radiation therapy. The three-electrode electron gun and C-band accelerating structure are optimised to produce a therapeutic electron beam with an energy of 6 MeV and a dose rate of 10 Gy/min and a beam with an energy of 2.5 MeV to obtain a portal image. The beam size at the bremsstrahlung target in both modes does not exceed 2 mm. The total length of the accelerating system with the electron gun does not exceed 330 mm. The accelerating structure is fed by RF power from a multibeam klystron at a frequency of 5,712 MHz with a maximum pulsed power of 3.5 MW.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO097
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO098	Proof-of-Principle Tests for Slit-scan-based Slice Emittance Measurements at PITZ	emittance, FEL, laser, space-charge	553
	R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, C. Saisa-ard, F. Stephan, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Transverse slice emittance is one of the most important properties of high-brightness electron beams for freeelectron lasers (FELs). The photo injector test facility at DESY in Zeuthen (PITZ) develops high-brightness electron sources for modern FELs. With a 23 MeV, 1 nC beam at PITZ the experimental slice emittance characterization with the quadrupole scan technique is complicated by strong space charge effects. Combining the slit scan technique with a transverse deflecting cavity (TDS) allows for timeresolved emittance measurements of such a space-chargedominated beam. The first proof-of-principle results of slice emittance measurements at PITZ based on the ’TDS + slit scan’-technique are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO098
About •	paper received ※ 04 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO109	Electron Cloud Estimates for the Jefferson Lab EIC	sextupole, simulation, proton, dipole	563
	K.E. Deitrick, V.S. Morozov, T. Satogata JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In this work, we present preliminary estimates for electron cloud build-up and saturation for the ion ring of the Jefferson Laboratory Electron-Ion Collider (JLEIC) currently under development. Using the baseline ion ring design, we study the impact of various operational parameters on the behavior of the electron cloud for a 100 GeV proton beam, including estimated tune shifts.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO109
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO112	Calculation of Electron Beam Dynamics in Four Accelerating Stations for JINR Linear Electron Accelerator LINAC-200	linac, solenoid, detector, acceleration	566
	A. Sledneva, V. Aleksandrov, V.V. Kobets JINR, Dubna, Moscow Region, Russia
	In the Joint Institute for Nuclear Research a Test Stand with an electron beam generated by the linear accelerator LINAC-200 with the energy up to 200 MeV is being constructed to investigate properties of accelerating and semiconducting structures for advanced detectors, a radiation resistance of detectors based on gallium arsenide semiconductor, to study a free electron laser and to do other applied for work. The technical characteristics of the LINAC-200 accelerator make it possible to create an advanced system of test beams for scientific and methodological studies of detectors on its basis. Four accelerating stations with maximum beam energy up to 200 MeV are put into operation. The work is being carried out for experiments with electron test beams with energy up to 800 MeV. This work presents the calculation results of the magnetic field of the focusing solenoidal system and electron beam dynamics in accelerating stations. In addition, the results on the formation of the electron beam with optimal parameters to be captured in further accelerating sections.
	Poster TUPO112 [1.176 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO112
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUPO119	A Diagnostics Box for the Linear Accelerator of Institute for Research in Fundamental Science (IPM)	linac, diagnostics, dipole, solenoid	581
	S. Sanaye Hajari, M. Bahrami, H. Behnamian, S. Kasaei, H. Shaker IPM, Tehran, Iran S. Ahmadiannamin ILSF, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran
	The IPM linac is an 8 MeV (up gradable to 11 MeV) electron linear accelerator under development at Institute for Research in Fundamental Sciences, Tehran, Iran. The design and construction of the linac is nearly finished and it is in the commissioning stage. The commissioning is planned in several phase of different energy ranging from 50 keV to 8 MeV. At each phase appropriate diagnostics is required in order to investigate the linac performance. A diagnostics box including a scintillator view screen, a dipole magnet, and a focusing solenoid is designed to diagnose the beam longitudinal and transverse parameters in wide range of energy. These parameters are the beam transverse profile, size, position, emittance and the energy spectrum.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO119
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUPO120	The Study of the Length and Shape of Beam in a High Power Electron Accelerator	radiation, extraction, industrial-accelerators, simulation	584
	M. Salehi, F. Abbasi Davani, B.G. Ghasemi Shahid Beheshti University, Tehran, Iran F. Ghasemi, A.P. Poursaleh NSTRI, Tehran, Iran
	The output beam of a high-power linear accelerator, used for industrial purposes, is irradiated on products and scanning them. In order to improve the dosimetry of radiation which products received and to prevent loss of the attacked- beams to the edge of products, the exact evaluation of scanning length is necessary . One of the other challenges of the scanning beam is the lack of uniformity in dosimetry of received radiation . The scanning beam does not collide in parallel to the products, which is also a challenge to accelerator efficiency. To improve dosimetry of received radiation, the use of trajectory correction magnets is suggested. These magnets correct the beams that do not scan in parallel. Also, using the Monte Carlo code, the dosing rate of received radiation to products is simulated and compared in two non-uniform and uniform modes (corrected by trajectory correction magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO120
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO127	Activities at the Linac4 Test Stand	emittance, rfq, linac, extraction	587
	J.-B. Lallement, V. Bencini, S.B. Bertolo, F.D.L. Di Lorenzo, J. Lettry, A.M. Lombardi, C.M. Mastrostefano, D. Noll, M. O’Neil CERN, Geneva, Switzerland
	Linac4, the new CERN H⁻ injector to the Proton Synchrotron Booster, has been commissioned and has delivered a beam intensity and quality calculated to be sufficient to produce the standard beams for LHC and the high intensity beams for ISOLDE when connected. The beam current is nevertheless half of what is foreseen and the problem has been identified at the low energy end, between the extraction and the matching to the RFQ. The Linac4 test stand is being used to address this issue by testing different extraction geometries and different plasma generators. A fast method to access the current in the RFQ acceptance has been put in place. This paper reports the results of the measurements obtained so far.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO127
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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WE1A03	Latest Results of CW 100 mA Electron RF Gun for Novosibirsk ERL Based FEL	cavity, gun, cathode, radiation	598
	V. Volkov, V.S. Arbuzov, E. Kenzhebulatov, E.I. Kolobanov, A.A. Kondakov, E.V. Kozyrev, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, A.A. Murasev, V.K. Ovchar, V.M. Petrov, A.M. Pilan, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, S.S. Serednyakov, O.A. Shevchenko, S.V. Tararyshkin, A.G. Tribendis, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia
	Continuous wave (CW) 100 mA electron rf gun for injecting high-quality 300-400 keV electron beam to the Energy Recovery Linac (ERL) driving the Novosibirsk Free Electron Laser (FEL) was developed, built, and commissioned in a diagnostics beam line. The rf gun consists of normal conducting 90 MHz rf cavity with a gridded thermionic cathode unit. Tests of the rf gun confirmed its design performance in strict accordance with numerical simulations. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the rf gun are presented. The commissioning experience is discussed. The latest beam results are reported.
	Slides WE1A03 [2.829 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A03
About •	paper received ※ 14 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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WE1A05	SwissFEL Linac Commissioning Status, Current Performance and Future Plans	linac, FEL, experiment, operation	605
	P. Craievich PSI, Villigen PSI, Switzerland
	SwissFEL, the hard x-ray free-electron laser facility at PSI, is in an advanced commissioning phase. The commissioning of the 5.8 GeV Linac started in 2016 and the first FEL pilot-experiments were performed at a reduced beam energy in the end of 2017. In 2018, it is foreseen to progressively increase the electron beam energy and photon energy up to the maximum design values, interleaved by several FEL pilot experiments. This paper gives an overview of the commissioning progress including the achieved machine performance and first operational experience.
	Slides WE1A05 [10.370 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A05
About •	paper received ※ 18 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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WE1A06	Pulse-to-pulse Beam Modulation for 4 Storage Rings with 64 Pulsed Magnets	power-supply, controls, positron, linac	609
	Y. Enomoto, K. Furukawa, T. Kamitani, F. Miyahara, T. Natsui, M. Satoh, K. Yokoyama, M. Yoshida KEK, Ibaraki, Japan H.S. Saotome Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	The KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is planned to inject electron and positron beams with energies from 2.5 GeV to 7 GeV pulse-by-pulse at 50 Hz into the dual ring SuperKEKB collider and two light source storage rings. As the beam quality requirement from SuperKEKB is demanding, the beam orbit and optics conditions have to be maintained precisely. To that end 64 newly designed pulsed magnets were installed. Quadrupole magnets with the inductance of 1 mH are driven by power supplies with pulses up to 330 A and 0.5 ms, which recover the energy stored in coils up to 65%. Orbit corrector magnets with the inductance of 3 mH are driven with bipolar pulsed power supplies up to 10 A. Those power supplies are controlled under the event-based synchronized controls and monitored pulse-by-pulse, and are confirmed to have the stability over weeks within 0.1%. The details of the design and the operational performance will be reported.
	Slides WE1A06 [6.694 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A06
About •	paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TH1A01	First Ever Ionization Cooling Demonstration in MICE	emittance, experiment, detector, scattering	632
	J.Y. Tang IHEP, Beijing, People’s Republic of China
	Funding: STFC, DOE, NSF, INFN, CHIPP and more The Muon Ionization Cooling Experiment (MICE) at RAL has studied the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. This invited talk presents and discusses these results, and projects the future of ionization cooling. Abstract submitted by the speakers bureau of the MICE Collaboration. If accepted, a member of the collaboration will be selected to present the contribution
	Slides TH1A01 [6.524 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A01
About •	paper received ※ 19 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019
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TH1A03	High Brightness Electron Beams from Plasma-based Acceleration	plasma, acceleration, FEL, simulation	637
	A. Marocchino, A. Biagioni, E. Brentegani, E. Chiadroni, M. Ferrario, F. Filippi, A. Giribono, R. Pompili, A.R. Rossi INFN/LNF, Frascati (Roma), Italy A. Bacci Istituto Nazionale di Fisica Nucleare, Milano, Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Petrillo Universita’ degli Studi di Milano, Milano, Italy
	Funding: INFN-CNAF and CINECA for high performance computing resources. European Union Horizon 2020 programme N. 53782. Plasma Wakefield acceleration is a promising new acceleration techniques that profit by a charged bunch, e.g. an electron bunch, to break the neutrality of a plasma channel to produce a wake where a trailing bunch is eventually accelerated. The quest to achieve extreme gradient conserving high brightness has prompted to a variety of new approaches and techniques. Most of the proposed schemes are however limited to the only plasma channel, assuming in the vast majority of cases, ideal scenarios (e.g. ideal bi-gaussian bunches and uniform density plasma channels). Realistic start-to-end simulations, from the photo-cathode to FEL via a high gradient, emittance and energy spread preserving plasma section, are mandatory for paving the way towards plasma-based user facilities.
	Slides TH1A03 [25.814 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A03
About •	paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TH1A04	The Proton Driven Advanced Wake Field Acceleration Experiment (AWAKE) at CERN	plasma, proton, wakefield, acceleration	642
	S. Döbert CERN, Geneva, Switzerland
	The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wake field generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world’s first proton driven plasma wake field acceleration experiment. The experiment uses the 400 GeV proton beam from the SPS which travels through a 10 m long Rb-vapour plasma cell where it gets self-modulated and generates the plasma wake fields. Eventually an electron beam is injected externally to probe the wake-fields. AWAKE will has completed several experimental campaigns starting in 2016. Results from the initial characterization of the plasma cell and measurements of the seeded self-modulation of the proton beam will be presented. Experiments to accelerate externally injected electrons using the proton driven plasma wake fields will start in 2018 and first results will be reported.
	Slides TH1A04 [4.787 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A04
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO004	Pulsed Operation of CEBAF for JLEIC Injection	cavity, injection, linac, beam-loading	682
	J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. JLab Electron Ion Collider (JLEIC) is planning to use the recently upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The JLEIC electron injection requires 3-4µs long bunch trains with a 20-400ms spacing in between, resulting in uneven beam loading for the CW CEBAF. With the high beam current in JLEIC collider rings, the low duty factor of injection also requires to a very high pulsed beam current from CEBAF, exacerbating the transient beam loading issue. In this paper, we will present CEBAFs detailed pulsed operation scheme for JLEIC injection, as well as some experimental results at CEBAF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004
About •	paper received ※ 20 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO010	Novel Straight Merger for Energy Recovery Linacs	cavity, dipole, experiment, simulation	702
	K.E. Deitrick, A. Hutton JLab, Newport News, Virginia, USA A.C. Bartnik, C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S.A. Overstreet ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO016	Investigation of 2D PBG Waveguides for THz Driven Acceleration	GUI, acceleration, impedance, photon	714
	A. Vint, R. Letizia Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Letizia Lancaster University, Lancaster, United Kingdom
	Funding: Work supported by the STFC PhD Studentship Novel accelerating techniques that overcome the limitations of conventional RF technology are receiving significant interest. Moving from RF to the THz frequency range, higher gradient of acceleration of high energy beams can be achieved in miniaturised structures. Moreover, with respect to the optical frequency range, the THz regime allows for larger structures and better beam quality to be obtained. In this paper, we investigate the use of a 2D photonic bandgap (PBG) waveguide for THz driven electron acceleration. In accelerator applications, the properties of PBG waveguides can be exploited to damp higher order modes and offer low-loss dielectric confinement at high frequency. In particular, 2D PBG waveguides offer a good compromise between manufacturability, total photonic bandgap confinement, and ease of parallel illumination. The structure here proposed is optimised for maximum bandgap and single mode operation. Dispersion characteristics of the accelerating mode are studied to achieve the best compromise between high accelerating field and effective accelerating bandwidth, given a ~10% bandwidth of the THz driving pulse.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO016
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO017	Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment	kicker, injection, site, experiment	717
	M.R. Rehman Sokendai, Ibaraki, Japan K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa KEK, Ibaraki, Japan H. Iinuma Ibaraki University, Hitachi, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216. A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase. *H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO018	Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises	controls, linac, cavity, collider	721
	V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase SLAC, Menlo Park, California, USA A. Grudiev CERN, Geneva, Switzerland H. Zha TUB, Beijing, People’s Republic of China
	Accelerating structures are usually manufactured by precision turning of individual cells combined with precision milling for complex parts such as rf power couplers. These multiple parts are staked and brazed into a complete structure. We consider an alternative approach: precision milling of multiple cells and couplers into metal blocks that comprise halves or quadrants of the complete structure. We successfully produced a 12~GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype using this method. A previous prototype was designed as an open structure with a gap between cell irises. Here we describe a different approach, an accelerating structure which is brazed through irises. It is based on a multi-cell traveling wave structure designed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises structure was built at SLAC for high power tests at CERN. Here we describe the details of this process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO018
About •	paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO020	Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator	SRF, GUI, resonance, acceleration	725
	Y.T. Yuan HUST, Wuhan, People’s Republic of China K. Fan Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China Y. Jiang Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
	Funding: the National Natural Science Foundation of China The cyclotron auto-resonance accelerator (CARA) is a novel concept of accelerating continuous gyrating charged-particle beams to moderately or highly relativistic energies, which can be used as the high power microwave source and applied in environment improvement area, particularly in the flue gas pollution remediation. In CARA, the continuous-wave (CW) electron beam follows a gyrating trajectory while undergoing the interaction with the rotating TE-mode rf field and tapered static magnetic field. In the process of gyrating acceleration, the phase synchronization with the rf field is automatically maintained, so to speak, with auto-resonance. Simulation models are constructed to study the effect of rf field and static magnetic field on electron beam in CARA, where the beam energy, trajectory and velocity component are analysed. The simulation results match reasonably well with theoretical predication, which sets up a solid foundation for future designs of CARA.
	Poster THPO020 [1.448 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO020
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO021	Research on X Ray Characteristics Produced by Highenergy Picosecond Electron Beam Shooting	target, photon, linac, radiation	729
	X.D. Zhang, X.P. Ouyang, B. Sun, X.J. Tan, X.F. Weng NINT, Xi’an, People’s Republic of China
	Funding: Supported by National Natural Science Foundation of China(11375142) The X ray sources based on electron linac can produce X-rays with high energy, concentrated directions, and strong penetrating power, which have been widely applied in various fields. An electronic linear accelerator which has been built at present can provide an electron beam with energy of 120 MeV and pulse width of picosecond. The electron beam shooting at the metal targets can produce ultra-fast pulsed X-rays in the order of picosecond. In this paper, the pulse X ray characteristics are studied through simulating electron beam shooting at four metal targets with different thickness of Au, Ta, U, W and Pb by MCNPX program. The calculation shows that the X-rays can reach about 1010p/pulse and the pulse width can reach about picosecond level, when the pulsed electron beams with energy of 120 MeV ,charge of 0.5nC and pulse width of picosecond shooting at Ta targets. The yield and time width of pulsed X-rays are related to the diameter and thickness of the target.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO021
About •	paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO069	The Electromagnetic Optimization of TE-sample Host Cavity at IMP	cavity, SRF, niobium, linac	852
	S.C. Huang, Y. He, T. Tan, S.X. Zhang IMP/CAS, Lanzhou, People’s Republic of China
	As a part of the research and development work of thin-film materials for superconducting radio frequency(SRF) application in future accelerators at IMP, a 3.9GHz TE sample host cavity is being developed for the purpose of characterizing the RF Property and the loss mechanism of thin-film materials, which operates in the TE011 mode and accommodates disk sample with 110mm diameter, theoretically, the maximum magnetic field on sample surface will go up to 100mT, the resolution of surface resistance on sample will below nOhm by using thermometry technique( T-Mapping). In this paper, the electromagnetic optimization result of TE-sample host cavity will be presented, and the design consideration of hook tip style coupler and T-mapping system are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO069
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO079	RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations	cavity, diagnostics, emittance, operation	866
	V.V. Paramonov RAS/INR, Moscow, Russia K. Flöttmann DESY, Hamburg, Germany
	For diagnostic of longitudinal distribution of electrons in unique REGAE bunches is applied a specially developed deflecting structure with minimized level of aberrations in the field distribution and improved RF efficiency. Short deflecting cavity was constructed and installed now in REGAE beam line. The cavity is tested at operational level of RF power. The main distinctive features of the cavity are mentioned and obtained results are reported.
	Slides THPO079 [1.803 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO082	Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement	cavity, simulation, FEL, coupling	872
	J. Bai, Q.S. Chen, K. Fan HUST, Wuhan, People’s Republic of China
	Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.
	Poster THPO082 [0.484 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO084	BPM Time of Flight Measurements for Setting-up the RF Cavities of the CERN Linac4	linac, cavity, DTL, simulation	879
	M. Bozzolan CERN, Geneva, Switzerland
	The newly constructed H⁻ LINAC4 at CERN has recently completed its first extended reliability run. It is equipped with Beam Position Monitors (BPMs) based on shorted-stripline pick-up electrodes to measure both position and Time of Flight (ToF). The ToF, in turn used to calculate the kinetic energy of the beam, is determined through signal phase shift measurements between pairs of BPMs. ToF measurements are performed by scanning of the phase of the RF injected into the cavities to find the nominal RF settings for optimal beam acceleration. This paper focuses on the technical aspects of the ToF measurement as well as on the results obtained during beam commissioning and their comparison with beam dynamics simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO084
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO086	Beam Loss and Average Beam Current Measurements Using a CWCT	proton, instrumentation, electronics, diagnostics	882
	F. Stulle, H. Bayle, J.F. Bergoz, T. Delaviere, L. Dupuy BERGOZ Instrumentation, Saint Genis Pouilly, France P. Forck, M. Witthaus GSI, Darmstadt, Germany D. Vandeplassche SCK•CEN, Mol, Belgium J.X. Wu IMP/CAS, Lanzhou, People’s Republic of China
	The CWCT is a novel instrument adapted to an accurate average current determination of bunched CW beams or macro pulses. By combining a high-droop current transformer with novel electronics for signal analysis, an output signal bandwidth of DC to about 500kHz and a current resolution down to the micro-ampere level are achieved. Beam current fluctuations are followed within microseconds, permitting fast detection of beam loss. These characteristics render the CWCT an ideal instrument for HPPAs, for example ADS linacs, and other proton or ion accelerators. We present the CWCT principle and the CWCT performance achieved in beam experiments at UNILAC, GSI.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO086
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO091	90 kW Solid-state RF Amplifier with a TE011-mode Cavity Power-combiner at 476 MHz	cavity, controls, FEL, power-supply	889
	Y. Otake, T. Asaka, T. Inagaki RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Aizawa, K. Nagatsuka, T. Okuyama, K. Sato, H. Yamada Nihon Koshuha Co. Ltd, Yokohama, Japan
	Solid-state RF amplifiers, which have long lifetimes and small failures, are the recent trend of reliable and stable high-power rf sources for particle accelerators. Hence, we designed a 90kW solid-state amplifier with an extreme low-loss TE011 mode cavity (Q0=100, 000) power-combiner operated at 476 MHz and a 6 us pulse width. Developing this amplifier is for replacement of an IOT rf amplifier, at the X-ray free-electron laser, SACLA. In SACLA, highly RF phase and amplitude stabilities of less than 0.02 deg. and 10^-4 in rms are necessary to stable lasing within a 10 % intensity fluctuation. The amplifier comprises a drive amplifier, a reentrant cavity rf power divider, 100 final amplifiers with a 1 kW output each and a TE011 mode cavity combiner. Water-cooling within 10 mK and a DC power supply with a noise of less than -100 dBV at 10 Hz for the amplifier is necessary to realize the previously mentioned stabilities. Based on the test results of the amplifier, the above-mentioned specifications with the extreme low-loss are promising. The amplifier also allows us to operate in pulsed and CW rfs for linacs and ring accelerators. We report the performance of the 90kW amplifier.
	Slides THPO091 [1.750 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO091
About •	paper received ※ 06 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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Paper

Title

Other Keywords

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MO2A03

Technology Developments for ELI-NP Gamma Beam System

laser, gun, linac, LLRF

13

L. Piersanti, D. Alesini, A. Battisti, M. Bellaveglia, S. Bini, F. Cardelli, R.D. Di Raddo, A. Falone, A. Gallo, V.L. Lollo, L. Pellegrino, S. Pioli, S. Tomassini, A. Variola
INFN/LNF, Frascati (Roma), Italy
N. Beaugerard
SEIV, Mérignac, France
K. Cassou, D. Douillet, K. Dupraz, T. Le Barillec, A. Martens, C.F. Ndiaye, Y. Peinaud, Z.F. Zomer
LAL, Orsay, France
L. Ficcadenti, A. Mostacci, L. Palumbo, V. Pettinacci
INFN-Roma, Roma, Italy
M. Migliorati
INFN-Roma1, Rome, Italy
D.T. Palmer, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
H. Rocipon
ALSYOM, Argebteuil, France

ELI-NP gamma beam system (GBS) is a linac based gamma-source in construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy, from 0.2 to 19.5 MeV, and with intensity and brilliance beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and an intense laser pulse at 100 Hz repetition rate. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation and laser recirculation at the interaction point. In this paper, the main technological developments carried out by the EuroGammaS consortium for the generation of the ELI-NP gamma beam will be described with a special emphasis on the electron linac technology, such as: RF-gun and C-band accelerating structures design fabrication and tests; low level RF (LLRF) and synchronization systems specifications and development. Finally, the laser recirculation apparatus design is briefly described and first results reported.

Slides MO2A03 [9.121 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A03

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MO2A04

Compact SRF Linac for High Brilliance Inverse Compton Scattering Light Source

laser, brilliance, emittance, gun

19

K.E. Deitrick, J.R. Delayen, G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
J.R. Delayen, G.A. Krafft
JLab, Newport News, Virginia, USA

New designs for compact SRF linacs can produce micron-size electron beams. These can can be used for inverse Compton scattering light sources of exceptional flux and brilliance.

Slides MO2A04 [1.717 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A04

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO005

Commissioning of the Normal Conducting Cavities for LEReC Project

cavity, booster, MMI, vacuum

44

B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, A. Zaltsman
BNL, Upton, Long Island, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is designed, and is currently under commissioning at BNL. The linac of LEReC consists of a DC photoemission gun, a 704 MHz superconducting radio frequency (SRF) booster cavity, a three-cell 2.1 GHz third harmonic cavity for RF curvature correction, a single-cell 704 MHz cavity for energy de-chirping and a 704 MHz deflecting cavity for diagnostic line. In this paper, we present the commissioning of three normal conducting cavities mentioned above.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO005

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paper received ※ 14 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO007

The Developing of the Beam Injection Section with Laser Source and S-Band Electron RF Gun for SuperKEKB Project

laser, gun, MMI, emittance

50

X. Zhou, Y. Ogawa, M. Yoshida, R. Zhang
KEK, Ibaraki, Japan

For the beam injection at Linac Accelerator of the SuperKEKB project, the s-band RF gun needs to provide low-emittance high-charge electron bunches. An ultrashort high energy solid laser driving a cathode in a quasi-travelling side-coupled RF gun were developed. A Yb fiber and Nd:YAG hybrid laser amplify system is start with 114.24 MHz oscillator that synchronized from accelerator. Two beam lines with the 25Hz, ~20ps, and sub-mJ Ultraviolet pulses were generated to RF gun. Ir5Ce has long lifetime and quantum efficiency QE that was employed to cathode. The RF gun has two side coupled cavities on same axis can realize quasi-traveling wave, which is suitable for the high charge and low emittance beam generation. Now, great progress has been made to make the RF gun function well. For the Phase II commissioning, required charge and emittance were achieved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO007

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paper received ※ 05 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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MOPO008

The RF Gun Adopting the Dielectric Assist Accelerating Structure

cavity, cathode, emittance, gun

54

S. Mori, D. Satoh, M. Yoshida
KEK, Ibaraki, Japan

We apply the dielectric assist accelerating (DAA) structure to the RF gun, which is a candidate for a high average current and high brightness electron source. The DAA structure consists of ultralow-loss dielectric cylinders and disks which are periodically arranged in a metallic enclosure. Due to the high quality factor and the high shunt impedance of the DAA cavity, the RF gun adopting the DAA cavity can be a high-duty electron beam source at room temperature. We provide design work for RF gun adopting the DAA structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO008

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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MOPO009

ELI-NP Gamma Beam System - Current Project Status

laser, linac, gun, experiment

59

P.S. Tracz
IFIN-HH, Bucharest - Magurele, Romania

The Gamma Beam System at the ELI-NP under construction in Magurele/Bucharest Romania, aims at producing high brilliance gamma-rays based on the laser Compton back-scattering, up to 3.5 and 19.5 MeV out of two interaction chambers. The design of warm RF electron linac is optimized to meet the unique source specification i.e. high brilliance, small relative bandwidth, tunable energy, and high spectral density. Together with technological development in field of high energy/high quality lasers it will open new opportunities for nuclear physics research in fields like nuclear photonics, nuclear astrophysics, photo-fission, and production of exotic nuclei, applications in industry, medicine, and space science. S-band laser driven RF photo-gun and two accelerating structures constitute the injector. The beam is then accelerated by C-band linac up to 350MeV (low energy linac), and up to 720MeV (high energy linac). The GBS was designed and is being constructed by the EuroGammaS - a consortium of European academic and research institutions and industrial partners. This paper gives an overview of the facility, describes the main linac systems and summarizes the project status.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO009

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO010

JINR Photocathode Research: Status and Plans

cathode, laser, gun, scattering

62

M.A. Nozdrin, N. Balalykin, J. Huran, V.F. Minashkin, G. Shirkov
JINR, Dubna, Moscow Region, Russia
E. Gacheva, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
J. Huran
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic

Photocathode research in the frame of the "transmission" photocathode conception (backside illuminated cathode based on a quartz/sapphire plate or a metal mesh which is a substrate for thin film made of a photomaterial) is being conducted in the Veksler and Baldin Laboratory of High Energy physics (LHEP) of the Joint Institute for Nuclear Research (JINR). Status of the 30-kev DC Photogun test bench and recent results of the extremely thin carbon film based cathodes research are described. Progress in the full-scale photoinjector prototype (max electron energy of 400 keV) is given. Startup of the photoinjector was performed, 70 keV electrons were extracted (650 pC).

Poster MOPO010 [1.564 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO010

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO016

Narrow-Band Terahertz Generation from Beam Pipe with Helix Wires

radiation, wakefield, simulation, impedance

65

D. Wang
TUB, Beijing, People’s Republic of China

We studied through analysis and numerical simulations the use of a relativistic electron bunch to drive a metallic beam pipe with helix wire inside, for the purpose of gen-erating narrow-band terahertz radiation. we have shown that the frequency is related to the radius of the pipe and that of the wire, thus one can generate a narrow-band radiation pulse with frequency tunable through this scheme with different pipes and wires. The total energy of a few milli-Joules. The pulse length tends to be on the order of hundreds of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp.
*wangdan2016@mail.tsinghua.edu.cn
*yanlx@mail.tsinghua.edu.cn

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO016

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paper received ※ 12 September 2018 paper accepted ※ 15 January 2019 issue date ※ 18 January 2019

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MOPO018

Development of an Improved Capture Section for the S-DALINAC Injector*

cavity, linac, simulation, gun

68

S. Weih, M. Arnold, J. Enders, N. Pietralla
TU Darmstadt, Darmstadt, Germany
D.B. Bazyl, H. De Gersem, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany

For the injector of the superconducting Darmstadt electron linear accelerator S-DALINAC, the design of a new capture cavity was recently completed. This beta-reduced structure will optimize the capture of low-energy electron bunches from the gun section and therefore improve the longitudinal beam quality of the injector beam, as simulations have shown. The existing cryomodule of the injector has to be modified for the installation of the new cavity. These modifications include adaptions of the tuner frame as well as modifications of other surrounding parts. To improve the diagnostics in the low-energy section, an energy-spread measurement setup is currently also under development. In this contribution the cryomodule modifications as well as simulation results for the longitudinal beam dynamics are presented.
*Work supported by DFG through GRK 2128 "AccelencE"

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO018

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO020

Beam Dynamics Studies and Instrumentation Tests for Bunch Length Measurements at CLEAR

experiment, gun, simulation, radiation

74

L. Garolfi, M. Bergamaschi, R. Corsini, A. Curcio, S. Döbert, W. Farabolini, D. Gamba, I. Gorgisyan
CERN, Geneva, Switzerland
C. Bruni, P. Lepercq, H. Purwar, C. Vallerand
LAL, Orsay, France
W. Farabolini
CEA/DSM/IRFU, France

A new CERN Linear Electron Accelerator for Research (named CLEAR) has been installed as a general-purpose user facility to study novel accelerating techniques, high-gradient structures, instrumentation and irradiation experiments. CLEAR is a flexible accelerator that can provide high quality bunched electron beams with a wide range of beam parameters up to an energy of 220 MeV, offering several testing capabilities. Among all the potential applications, novel accelerating techniques, such as plasma acceleration and THz generation are considered. These applications require shorter bunches, down to the 100 fs level. This paper reports on beam dynamics studies and instrumentation tests to establish a bunch length of this order in CLEAR. The short bunches are generated using adiabatic bunching in the first accelerating structure. For bunch length diagnostic CLEAR is equipped with a streak camera and a transverse deflecting cavity. Alternatively a phase-scan of the last accelerating structure could be used as well to estimate the bunch length. The experimental results with respect to these different techniques are presented and compared with simulations.

Slides MOPO020 [0.864 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO020

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO024

Development of High Power Coherent Terahertz Wave Sources at Lebra 125 MeV Linac in Nihon University

FEL, radiation, linac, undulator

78

T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, Y. Sumitomo, Y. Takahashi, T. Tanaka
LEBRA, Funabashi, Japan
H. Ogawa, N. Sei
AIST, Tsukuba, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number JP16K17539 and JP16H03912.
Research and Development of a high performance electron linac for the generation of FEL, Parametric X-ray Radiation (PXR) and THz waves has been continued at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University as a joint research with KEK and National Institute of Advanced Industrial Science and Technology. The transport systems of the THz wave were installed in the vacuum chamber on the downstream side of the bending magnet of the PXR and FEL beam-line. The CER and the CSR are generated by the bending magnet each of the beam line. In addition, the CTR using thin metal foil is also generated. The average power of the CTR wave was measured approximately 1 mJ/macro-pulse (pulse width 4.5 µs) near the CTR wave beam source point in the frequency range of 0.1 - 2.5 THz. In addition, the energy of the CER as high as 0.2 mJ/macro-pulse were achieved with the experimental room. Furthermore, CER of the generated the FEL beam line can also be guided from the bending magnet on the downstream side of the undulator without disturbing the FEL oscillations. THz transport beam-lines and the characteristics of the THz waves are discussed in this report.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO024

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO026

The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac

cavity, controls, coupling, radio-frequency

81

M. Mohseni Kejani, F. Abbasi Davani
Shahid Beheshti University, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO027

Photocathode Laser Pulse Shaping for Improved Emittance

laser, cathode, gun, emittance

84

M. Kotur, J. Andersson, J. Björklund Svensson, M. Brandin, F. Curbis, L. Isaksson, F. Lindau, R. Lindvall, E. Mansten, R. Svärd, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

We present a setup for producing and characterizing picosecond ultraviolet laser pulses for use in the MAX IV photocathode electron gun preinjector. Frequency-tripled laser pulses from a commercial laser system are shaped directly in the ultraviolet domain using a Fourier-domain pulse shaper. The pulses were characterized using a transitent grating FROG. We discuss a proposed upgrade of the pulse shaper, as well as its limitations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO027

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO028

Survey and Alignment System of 100 MeV/100 kW Electron Linear Accelerator

quadrupole, target, survey, neutron

87

O. Bezditko, I.I. Karnaukhov, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine

For successful operation and working of electron linear accelerator of "NEUTRON SOURCE" driver it is necessary that all the acceleration sections, the quadrupole triplets, the quadrupole lenses, the dipole magnets, the scanning magnets and the chicane should be installed in design position according design parameters. Accuracies of all electromagnetic elements installation are 150 mkm for all three rotation freedom. The whole process, fiducialization and developing of survey net, alignment is controlled by laser tracker Leica AT 401.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO028

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO029

Physics design and dynamic simulation of a C-band photocathode electron gun for UEM

gun, emittance, cathode, solenoid

90

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

For discovering structure at atomic scale and getting more details of chemical material and biological tissue, an ultrafast electron microscopy (UEM) has been developed and applied in plenty of subjects and studies. This paper described a C-band photocathode electron gun which will be working at 5712MHz to produce ultrashort electron beams with better dynamic parameters. The RF gun is using coaxial coupler to decrease the size of the gun and keep better symmetry of the field in the photocathode gun so that the beam emittance and energy spread can be reduce a lot. The photocathode rf gun will be a important part of the ultrafast electron microscopy (UEM). Using CST MWS and superfish code to simulate design the gun. After dynamic simulation, the beam parameters as the following: Energy is of 3MeV, Normal emittance of 0.12mm-mrad in boin direction, energy spread is of 5.8·10^-4, which are better enough for an UEM.

Poster MOPO029 [3.599 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO029

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paper received ※ 11 September 2018 paper accepted ※ 22 September 2018 issue date ※ 18 January 2019

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MOPO034

Dielectric Waveguide-Based THz Radiator Study for SwissFEL

experiment, radiation, FEL, GUI

94

L. Shi, S. Bettoni, M.M. Dehler, E. Ferrari, B. Hermann, R. Ischebeck, F. Marcellini, S. Reiche, V.G. Thominet
PSI, Villigen PSI, Switzerland
A.K. Mittelbach
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647
THz pulses have many unique properties in terms of radiation matter interaction. In particular their non-ionizing excitation of phonons in matter makes them a preferred pump for pump-probe studies at free electron lasers. In order to enrich the scientific potentials at SwissFEL (Swiss Free Electron Laser), which can provide ultrashort soft and hard X-ray pulses, we plan to build an economic THz radiator in the range of 1-20 THz by passing the spent electron beam through a dielectric lined tube after the electron beam has generated X-rays. These THz pulses will be transported to the photon user station. Since SwissFEL operates with 2 bunches, serving two beamlines, THz from the first bunch can be used at the user station of the second bunch to allow for pump arrival time before the probe. The core of such a THz generation setup is the dielectric lined tube and the relativistic electron beam. This paper reports on the numerical study of these tubes, in terms of mode structure, energy, pulse length etc, which are essential parameters for the pump-probe experiments. These tubes will be fabricated and tested in the near future in the electron beam line for the soft X-ray of SwissFEL.

Slides MOPO034 [1.471 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO034

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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MOPO039

Status Update of the Fast Energy Corrector Cavity at FLASH

cavity, laser, coupling, free-electron-laser

112

S. Pfeiffer, J. Branlard, L. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella
DESY, Hamburg, Germany
M. Fakhari
CFEL, Hamburg, Germany

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.

Poster MOPO039 [1.884 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039

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paper received ※ 13 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO040

Coherent Synchrotron Radiation Monitor for Microbunching Instability in XFEL

radiation, laser, bunching, FEL

115

J.H. Ko, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
H.-S. Kang, C. Kim, G. Kim
PAL, Pohang, Kyungbuk, Republic of Korea

The microbunching instability is an important issue in an X-ray Free Electron Laser (XFEL). The intensity of the FEL can be reduced significantly by the microbunching instability so that the laser heater is widely used to reduce it. In the X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL), to directly monitor the microbunching instability, a visible CCD camera was included into the coherent radiation monitor (CRM) which uses a pyroelectric detector. It enabled us to measure the microbunching instability more clearly and optimize the FEL lasing in the PAL-XFEL.

Slides MOPO040 [1.125 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO040

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO042

Evolutionary Many-objective Optimization Algorithm for Large-bandwidth Free-Electron-Laser Generation

FEL, free-electron-laser, laser, linac

121

J.W. Yan, H.X. Deng
SINAP, Shanghai, People’s Republic of China

Funding: National Natural Science Foundation of China , the National Key Research and Development Program of China, the Young Elite Scientist Sponsorship Program by CAST and Ten Thousand Talent Program.
X-ray free-electron lasers (XFELs) are leading-edge instruments in a wide range of research fields. Besides pursuing narrow bandwidth FEL pulses, the large-bandwidth XFEL pulses are very useful in various spectroscopy experiments, multi-wavelength anomalous diffraction, and X-ray crystallography. Overcompression operation scheme can be utilized to generate electron beams with large energy chirp which is benefit for bandwidth broadening. Recently, an evolutionary many-objective (having four or more objectives) algorithm, NSGA-III, was used to optimize the electron beam parameters in the overcompression including energy chirp, energy spread, current profile, peak current, and projected emittance. In this paper, combining with the Xie’s semianalytical estimate formula, the NSGA-III is utilized to find an optimal working point of linac by optimizing the XFEL pulse properties directly. Start-to-end numerical simulations based on the Shanghai soft X-ray Free-Electron Laser user facility parameters demonstrate that a full bandwidth of 4.75% can be generated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO042

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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MOPO058

Industrial Electron Linear Accelerator R&D in CIAE

gun, radiation, linac, controls

124

J.H. Yang, Y. Yang, G. Yu, Z.Q. Zeng
CIAE, Beijing, People’s Republic of China
Z.B. Zhu
China Institute of Atomic Energy, Beijing, People’s Republic of China

Electron linear accelerator(E-LINAC)is a vital accelerator type for accelerator applications, which widely applied in industry, agriculture and medical industry. The paper introduces R&D of industrial E-LINAC in China Institute of Atomic Energy (CIAE) , including electron gun, modulator, accelerating tube, assembling and testing. Based on these R&D results, the GT series for non-destructive testing(NDT) and FZ series for irradiation processing are developed successfully. At present these E-LINACs play important roles in pressure vessel inspection, food preservation, sterilization and material modification, promoting the E-LINACs application as well as economic development in China.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO058

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paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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MOPO060

Linacs for Industry, Cargo Inspection and Medicine Designed by Moscow University

controls, operation, klystron, radiation

130

A.N. Ermakov, A.S. Alimov, A.N. Kamanin, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov
SINP MSU, Moscow, Russia
A.S. Alimov, A.N. Ermakov, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, A.S. Simonov
LEA MSU, Moscow, Russia
I.V. Shvedunov
Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia

Funding: Work supported in part by Ministry of Education and Science of Russia Grant # RFMEFI58217X0011
The report presents the results of development of applied linear electron accelerators with an energy of up to 10 MeV, performed by the Laboratory of Electron Accelerators MSU. We describe linear accelerators for mobile, stationary and train cargo inspection systems with interlaced energies and pulse repetition rate up to 2 kHz, accelerators for radiography, a sterilization accelerator with beam parameters that are adjustable over a wide range, and an accelerator for a radiotherapy complex.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO060

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO061

Beam Parameters Measurement of C-band 6 MeV Linear Electron Accelerator

gun, controls, factory, klystron

133

D.S. Yurov, A.S. Alimov, A.N. Ermakov, V.V. Khankin, N.V. Shvedunov, V.I. Shvedunov
SINP MSU, Moscow, Russia
L. Ovchinnikova
Laboratory of Electron Accelerators MSU, Ltd, Physics Department, Lomonosov Moscow State University, Moscow, Russia
A.S. Simonov
LEA MSU, Moscow, Russia

The new linear electron accelerator with beam energy varied in the range of 2-6 MeV with dual-energy option has been designed by Laboratory of Electron Accelerators MSU Ltd. Linac is based on compact high gradient stand-ing wave C-band accelerating structure fed by multi-beam klystron and is used in the cargo inspection and cancer therapy complexes. In the report, we present the results of electron beam parameters measurements at special stand.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO061

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paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO062

Linear Electron Accelerator for Radiation Technologies with Beam Parameters Varied in a Wide Range

operation, radiation, controls, gun

136

V.V. Khankin, A.S. Alimov, A.N. Ermakov, A.N. Kamanin, A. Kurilik, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov
SINP MSU, Moscow, Russia
A. Kurilik
LEA MSU, Moscow, Russia
I.V. Shvedunov, A.S. Simonov
Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia

We present the overview and beam parameters measurements results as well as the operational experience with the S-band pulsed linear electron accelerator with beam energy in the range of 5-10 MeV and maximum beam power of up to 15 kW. The possibility of adjusting the beam parameters in a wide range, provided by the design and control system of the accelerator, allows to use the accelerator in a wide variety of radiation technologies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO062

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paper received ※ 07 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO063

Development of Side-coupled X-band Medical Linear Accelerator for Radiotherapy

cavity, linac, gun, target

139

Y.S. Lee, Y.W. Choi, G.J. Kim, I.S. Kim, J.I. Kim, S. Kim, J.H. Lee
KERI, Changwon, Republic of Korea
J.H. Hwang, Y.N. Kang, A.R. Kim, J.N. Kim, T.G. Oh, Y.A. Oh, Y. J. Seol, J.S. Shin
The Catholic University of Korea, Seoul, Republic of Korea

Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging devices such as CT or MRI, so that it is possible to precisely focus high dose radiation on tumor tissues while minimizing the normal tissue damage. In order to place the diagnostic and treatment devices simultaneously in a confined space, constraints related to interference and volume between the subsystems must be considered. To meet these requirements, the size and weight of the LINAC system need to be reduced, which can be achieved by applying X-band technology. For the purpose of use in IMRT based on image guided radiotherapy, we developed a 9.3 GHz X-band medical LINAC using side-coupled structure. The LINAC is designed to have the accelerating field strength of 16.8 MV/m, and the beam current transmission efficiency of 26 % at the end of accelerating cell when the supplied RF power is at 1.7 MW. Therefore, it can accelerate the electron beam up to 6.2 MeV with having about 90 mA beam current. We plan to carry out the performance test using beam diagnostics system and X-ray measurement system, and the details of design and experimental results of LINAC will be described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO063

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO069

Nuclear and Mechanical Basic Design of Target for Mo-99 Production Using High Power Electron Linac

target, photon, neutron, linac

148

A. Taghibi Khotbeh-Sara, F. Rahmani
KNTU, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
H. Khalafi
AEOI, Tehran, Iran
M. Mohseni Kejani
Shahid Beheshti University, Tehran, Iran

Today providing enough supplies of 99mTc / 99Mo as a high usage radioisotope in diagnostic nuclear medicine for the world demand is a big challenge. One of the proofed ways to access reliable source of this radioisotopes is production using e-LINAC [1]. In this investigation it was tried to find the simple and the optimized design of 99Mo production target based on photoneutron reaction using e-LINAC. Based on the Monte-Carlo calculation for radiation transport and finite element thermal analysis, 9 thin plates of enriched 100Mo was suggested. Equal distance between plates was considered for cooling to prevent target melting. The main target includes only 100Mo in one-stage approach method to increase production rate in compare with two-stage approach [2]. Applying 2.5 m/s for inlet velocity of cooling water provides suitable cooling process with maximum temperature of target about 900 ˚C.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO069

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO070

Construction of the Side-coupled Standing-wave e-Linac

cavity, simulation, linac, coupling

151

S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
F. Abbasi
Shahid Beheshti University, Tehran, Iran
M. Bahrami, M. Lamehi
IPM, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

Due to Iran’s growing need for accelerators in various applications, NSTRI electron linear accelerator project has been defined for medical and inspection applications. This accelerator is a 6 MeV side-coupled standing-wave that operate is π /2 mode in the frequency of 2998.5 MHz. In this paper the construction and measurement results of the tube of this accelerator are presented. The prototype tube was constructed from aluminum and was clamped with bolts. By using a network analyzer, electric and magnetic probes and a side-coupled cavity tuning method and a bead-pull measurement technique, RF measurements were carried out. The resonant frequency and quality factor have been achieved 2998.5 MHz and 7940 respectively .
low-energy accelerator, construction of linac, standing-wave linac

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO070

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paper received ※ 12 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019

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MOPO073

Coherent Edge Radiation Sources in Linac-Based Infrared Free-Electron Laser Facilities

FEL, radiation, undulator, cavity

154

N. Sei, H. Ogawa
AIST, Tsukuba, Ibaraki, Japan
K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, T. Tanaka
LEBRA, Funabashi, Japan
H. Ohgaki, H. Zen
Kyoto University, Kyoto, Japan

Funding: This study was financially supported by JSPS KAKENHI Grant Number JP16H03912.
National Institute of Advanced Industrial Science and Technology has been studied far-infrared coherent radiation at Linac-based infrared free-electron laser (FEL) facilities in col-laboration with Nihon University and Kyoto University. To obtain high FEL gain at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University and at Kyoto Uni-versity Free Electron Laser (KU-FEL), the electron-bunch length is compressed to less than 1 ps in their undulator sections. Short electron bunches are suitable for generating intense coher-ent radiation, and we have already developed some terahertz-wave sources based on the coher-ent synchrotron radiation and the coherent transition radiation [1-3]. However, it was difficult to observe them with sufficient intensity without disturbing the infrared FEL oscillations. Then, we now develop coherent edge radiation emitted from downstream bending magnets in the un-dulator sections. It can be extracted from the undulator sections without disturbing the FEL os-cillations. In this presentation, the observed coherent radiation at LEBRA and KU-FEL will be reported on.
[1] N. Sei et al., J. Phys. D: Appl. Phys. 46, (2013) 045104.
[2] N. Sei et al., Nucl. Instr. and Meth. A, 832, (2016) 208.
[3] N. Sei et al., Jpn. J. Appl. Phys.: 56, (2017) 032401.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO073

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paper received ※ 29 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO076

Study on Generation of Variable Polarized Coherent THz Radiation Using a Crossed Undulator

undulator, radiation, polarization, controls

157

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

A variable polarized THz radiation source using a crossed undulator system has been developed at Tohoku University. In this scheme, two coherent undulator radiations from an extremely short electron bunch are used to control the polarization. They are linearly polarized radiations orthogonal to each other. Polarization of superimposed radiation is controlled by adjusting a relative phase between them. A compact planar undulator with seven periods has been designed for an experiment at our facility. The radiation frequency is 2.06 THz for electron beam energy of 22 MeV. The opening angle of the crossed undulator radiation was estimated to be 34 mrad (FWHM). Since the polarization state of the crossed undulator depends on observation angle, its angular dependence was evaluated. It was found that ideal polarization control is realized only in the angle range of 2.5 mrad, which is quite smaller than that of the radiation itself.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO076

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO118

Optimized Design for a Compact Linac with Collinear Absorbing Loads at the Hust FEL-THz

cavity, linac, FEL, radiation

242

J. Jiang, G. Feng, T. Hu, Y. Lu, X.D. Tu, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People’s Republic of China

To meet the requirement of miniaturization for high power THz radiation in the field of commercial and civil use, RF Linacs have been applied widely as beam injectors, and the Linac with collinear absorbing loads reveals the potential to achieve a tradeoff between performance and compactness. Under overall consideration of systematic conflicts, optimization choices for such Linacs involving power absorbing ability, accelerating efficiency, as well as beamline length were described in this context. Meanwhile, cold testing has been conducted to verify design parameters for the collinear absorbing loads. Furthermore, elaborated calculation of thermal power loss and integrated helical water channel cooling has been performed for the 14MeV Linac with collinear absorbing loads installed on the HUST FEL-THz, and online experiments demonstrated that both the accelerating efficiency and the water cooling performance fulfilled operation demands.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO118

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO121

Large-Scale Optical Synchronization System of the European XFEL

laser, FEL, timing, experiment

253

J.M. Müller, M. Felber, T. Kozak, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
DESY, Hamburg, Germany

At the European XFEL, a facility-wide optical synchronization system providing a femtosecond-stable timing reference at more than 40 end-stations had been developed and installed. The system is based on an ultra-stable, low-noise laser oscillator, whose signals are distributed via actively length-stabilized optical fibers to the different locations across the accelerator and experimental areas. There, it is used to locally re-synchronize radio frequency signals, to precisely measure the arrival time of the electron beam for fast beam-based feedbacks, and to phase-lock optical laser systems for electron bunch generation, beam diagnostics and user pump-probe experiments with femtosecond temporal resolution. In this paper, we present the system’s architecture and discuss design choices to realize an extensible, large-scale synchronization infrastructure for accelerators that meets reliability, maintainability as well as the performance requirements. Furthermore, the latest performance result of an all-optically synchronized laser oscillator is shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO121

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO122

European XFEL Cooling and Ventilation Systems

FEL, undulator, photon, controls

257

J.-P. Jensen
DESY, Hamburg, Germany

The European Free Electron Laser XFEL is operating since 2016. The technical systems for cooling and Ventilation CV were design, built and commissioned by the DESY work package WP34. The CV systems will be described and presented. The water cooling system consists of 3 cooling systems: 30/45 °C LCW for klystron and magnet cooling, 20/30 °C LCW for tunnel rack cooling and 8/14 °C for air conditioning and dehumidification of the air. The ventilation of the tunnels is connected to a series ventilation system from the experimental hall in direction to the injector. The series ventilation of the tunnels saves costs for air treatment with cooling, heating and dehumidification. The tunnel walls are a good heat storage that increases the air temperature stability by a factor of ten. The advantages of this concept will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO122

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TU1A03

Status and Issues (Microphonics, LFD, MPS) with TRIUMF ARIEL e-Linac Commissioning

cavity, linac, TRIUMF, MMI

286

S.R. Koscielniak, M. Alcorta, F. Ames, E. Chapman, K. Fong, B. Humphries, O.K. Kester, D. Kishi, R.E. Laxdal, Y. Ma, T. Planche, M. Rowe, S.D. Rädel, V.A. Verzilov, Z.Y. Yao
TRIUMF, Vancouver, Canada

The ARIEL electron linac (e-linac) is designed to generate cw beams of up to 30 MeV and 10 mA for delivery to a photo-convertor. Bremsstrahlung induced fission of a production target yields neutron-rich rare isotope beams to be supplied to the ISAC experimental facilities. The beam power will eventually reach 300 kW, and a machine protection system (MPS) with 10 μs rapidity is essential. The e-linac, which adopts 1.3 GHz, 2K SRF technology, is composed of a 10 MeV single-cavity injector cryomodule (EINJ) and a 20 MeV two-cavity accelerator cryomodule (EACA). The latter has vector-sum control of two cavities driven from a single klystron. Beam commissioning of these systems is ongoing since 2016. The magnetic optics and MPS commissioning to 10 MeV is reported herein. Beam has been accelerated up to 25 MeV, and thread-ed to the high energy dump (EHD). A campaign to investigate microphonics driving terms, LN2 disturb-ances, and a ponderomotive instability in the EACA, is underway.

Slides TU1A03 [9.683 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A03

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paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TU1P01

Extreme High Brightness Electron Beam Generation in a Space Charge Regime

cavity, emittance, space-charge, bunching

314

A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
L. Faillace, M. Rossetti Conti
Universita’ degli Studi di Milano & INFN, Milano, Italy

The generation of ultra-short, low emittance and low energy spread electron bunches is nowadays a critical requirement for accelerators in plasma wave or for femto-second light sources. A new longitudinal compression scheme, based on velocity and ballistic bunching tech-niques in presence of space charge forces, allows to enter in a peculiar regime, so-called laminar bunching (LB). In this regime, the bunch is longitudinally compressed, at the expense of its transverse size, and the over-bunching is forbidden by the laminarity: going to the minimal longi-tudinal dimension the bunch is adiabatically frozen and transversally refocused. Furthermore this technique heats slightly the uncorrelated energy spread resulting in elec-tron distributions that, in case of bending paths, does not require Laser Heater devices.

Slides TU1P01 [1.720 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1P01

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paper received ※ 12 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019

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TUPO001

About the Limits for the Accelerated Beam Current in the LUE-200 Linac of the IREN Facility

klystron, linac, neutron, acceleration

320

A.P. Sumbaev
JINR, Dubna, Moscow Region, Russia
A.M. Barnyakov, A.E. Levichev
BINP SB RAS, Novosibirsk, Russia

The beam current loading of the accelerating fields is discussed for the linear accelerator LUE-200 of IREN facility. LUE-200 electron Linac consits of two disk loaded travelling wave accelerating structure with the operating frequency of 2856 MHz and power compression SLED-type system. The limits by the accelerated beam current are defined for different pulse durations of the beam current and RF power. The calculated results are discussed and compared with the measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO001

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paper received ※ 12 September 2018 paper accepted ※ 22 January 2019 issue date ※ 18 January 2019

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TUPO002

Electron Gun for 100 MeV / 100 kW Linear Accelerator of Electrons as the Driver of Nuclear Subcritical Assembly Neutron Source

gun, cathode, neutron, controls

323

M. Moisieienko, O. Bezditko, A. Mytsykov, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine

100 MeV / 100 kW linear electron accelerator of The "neutron source" nuclear subcritical assembly uses the 120 KW triode electron gun as the primary source of electrons. The gun is designed, manufactured and tested at IHEP, Beijing, China. At present, the gun is installed, tested. The maximum impulse current of the gun equal to 2 A. Under design operation, the impulse current of the gun equal to 0.55 A.The report describes the construction of a 120 kV triode electron gun, the results of testing and test operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO002

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TUPO036

Vertical Test Results of Plasma In-situ Cleaning on Low Beta HWR Cavity

plasma, cavity, experiment, SRF

408

A.D. Wu, H. Guo, Y. He, C.F. Hu, S.C. Huang, C.L. Li, Y.M. Li, X. Liu, F. Pan, Y.K. Song, P.R. Xiong, L. Yang, W.M. Yue, C. Zhang, S.H. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Field emission occurred in SRF cavity is the major limitation to operate at high gradient with stability. The plasma in-situ cleaning for the low beta HWR cavity was carried out to remove the hydrocarbons contaminants on the inner cavity surface. And the vertical test results indicated that the field emission effect was relieved with the increasing of the quench point and emission set-on point. Thus, oxygen active plasma processing can be an effective method to solve the field emission issues for the low beta HWR cavity.

Slides TUPO036 [1.281 MB]

Poster TUPO036 [0.672 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO036

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paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUPO051

Design Considerations of a Balloon-shaped SSR Superconducting Cavity

cavity, simulation, distributed, superconducting-cavity

448

H.J. Cha, S.W. Jang, E.-S. Kim, K.R. Kim, S. H. Park, J.Y. Yoon
Korea University Sejong Campus, Sejong, Republic of Korea

A single spoke resonator (SSR, β = 0.51 and f = 325 MHz) is being developed at Korea University. It is well-known that a traditional spoke cavity having flat or round end walls has broad multipacting ranges in acceleration gradient, sometimes including operation region. In general, quite long conditioning time is consumed to overcome such multipacting barriers. In this study, we introduce a balloon-shaped SSR superconducting cavity for the multipacting mitigation due to structural simplicity. The electromagnetic modeling of the SSR was made based on the RF parameter optimization. The simulation results show much narrower multipacting bandwidth, compared to those for the traditional spoke cavity. Mechanical analyses with stiffening structure at maximum allowable working pressures indicate acceptable stresses at the SSR cavity wall. In addition, the resonant frequency shifts due to fabrication and processing for cold tests are predicted and power coupling and tuning mechanism are also investigated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO051

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUPO054

Fundamental Studies of Impurity Doping in 1.3 GHz and Higher Frequency SRF Cavities

cavity, niobium, SRF, radio-frequency

458

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

As the demand for more powerful, more efficient, and smaller superconducting RF accelerators continues to increase, both impurity doping and high-frequency cavities (> 1.3 GHz) have become hot topics for fundamental research because of their potential to significantly decrease surface losses and cost respectively. In this report, we present recent experimental and theoretical results on undoped and nitrogen-doped high-frequency cavities and on alternative doping agents in traditional 1.3 GHz cavities, with a focus on understanding the fundamental science of impurity doping.

Slides TUPO054 [1.956 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO054

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paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO064

Pre-study of CEPC SRF Cavity

cavity, SRF, cryomodule, collider

476

P. Sha
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People’s Republic of China
J. Dai, C. Dong, H.F.S. Feisi, S. Jin, Z.Q. Li, B.Q. Liu, Z.H. Mi, J.Y. Zhai, X.Y. Zhang, H.J. Zheng
IHEP, Beijing, People’s Republic of China
J.K. Hao, F. Wang
PKU, Beijing, People’s Republic of China

Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400) and National Natural Science Foundation of China (Grant NO.:11505197).
CEPC will use 650 MHz cavities for the collider and 1.3 GHz cavities for the Booster. Each booster cryomod-ule contains eight 1.3 GHz 9-cell cavities, which is simi-lar as LCLS-II, E-XFEL and ILC. Each collider cryo-module contains six 650 MHz 2-cell cavities, which is totally new. Therefore, the pre-study mainly focuses on the 650 MHz 2-cell cavity. N-doping and vertical tests of 650 MHz 1-cell and 2-cell cavities have been carried out at IHEP, which have achieved good results. A test cryomodule, which consists of two 650 MHz 2-cell cavities, has also begun as the first step to the full-scale cryomodule.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO064

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paper received ※ 31 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO078

Extension of Busch’s Theorem to Particle Beams

emittance, solenoid, experiment, cathode

516

L. Groening, C. Xiao
GSI, Darmstadt, Germany
M. Chung
UNIST, Ulsan, Republic of Korea

In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with longitudinal magnetic field. The theorem relates particle angular momentum to the amount of field lines being enclosed by the particle cyclotron motion. Recently it has been extended to accelerated particle beams [Phys. Rev. Accel. Beams 21 014201 (2018)]. This contribution sketches this extension and applies the extended theorem to successfully performed emittance manipulations with electron and ion beams.

Slides TUPO078 [0.999 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO078

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paper received ※ 24 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO090

Electron-beam Matching to Solenoid Magnetic Field in a Klystron

klystron, gun, solenoid, injection

534

S.J. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Hwang, S.-G. Shin
POSTECH, Pohang, Kyungbuk, Republic of Korea
S.Y. Hyun, D.H. Yu
Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea

Funding: The work was supported by the National R&D Program (grant number: 2016R1A6B2A01016828) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, Korea.
High-power klystrons for particle accelerators employ high-perveance electron guns which are usually focused by Solenoid magnets. The electron beam should be optically matched to the downstream magnetic field to prevent the beam from scalloping. The task usually requires a series of computer simulations with many design parameters, and therefore requires extensive(sometimes exhaustive) efforts if not aided by a priori experiences. In order to alleviate the difficulties we have developed a matching procedure which is systematic and reliable. In this article we describe the procedure with an example design of a 400-kV 500-A electron beam with radius 8 - 11 mm.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO090

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO092

Beam Dynamics and Collimation Following MAGIX at MESA*

target, simulation, scattering, radiation

540

B. Ledroit, K. Aulenbacher
IKP, Mainz, Germany

Funding: * Supported by the DFG through GRK 2128
The Mainz Energy-recovering Superconducting Accelerator (MESA) will be an electron accelerator allowing operation in energy-recovery linac (ERL) mode, where beam energy is recovered by decelerating the beam in linac cryomodules and transferring kinetic energy to the RF. The ERL mode provides the opportunity to operate experiments at peak energy with thin targets, combining high luminosities typical for storage rings and high beam brightness typical for linacs. The MESA Internal Gas Target Experiment (MAGIX) aims to operate jet targets at high luminosities with different gases up to Xenon. As scattering effects in the beam rise with the atomic number, investigations on the impact of the target on beam dynamics and beam losses are required for machine safety. The goal of this work is to understand target induced halo, track halo particles through downstream sections and protect the machine with a suitable collimation system and shielding from direct and indirect damage through beam losses and radiation. The present status of the investigations is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO092

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO097

Design of C-band Electron Linear Accelerator for a Complex of Radiation Therapy

gun, target, radiation, controls

550

L. Ovchinnikova, V.I. Shvedunov
SINP MSU, Moscow, Russia
L. Ovchinnikova, V.I. Shvedunov
LEA MSU, Moscow, Russia

Funding: This material is based upon work supported by the Ministry of Education and Science of the Russian Federation, under Grant Agreement No. 14.582.21.0011, Grant Agreement Unique ID RFMEFI58217X0011.
The report presents the design of the linear electron accelerator for a complex of radiation therapy. The three-electrode electron gun and C-band accelerating structure are optimised to produce a therapeutic electron beam with an energy of 6 MeV and a dose rate of 10 Gy/min and a beam with an energy of 2.5 MeV to obtain a portal image. The beam size at the bremsstrahlung target in both modes does not exceed 2 mm. The total length of the accelerating system with the electron gun does not exceed 330 mm. The accelerating structure is fed by RF power from a multibeam klystron at a frequency of 5,712 MHz with a maximum pulsed power of 3.5 MW.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO097

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUPO098

Proof-of-Principle Tests for Slit-scan-based Slice Emittance Measurements at PITZ

emittance, FEL, laser, space-charge

553

R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, C. Saisa-ard, F. Stephan, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Transverse slice emittance is one of the most important properties of high-brightness electron beams for freeelectron lasers (FELs). The photo injector test facility at DESY in Zeuthen (PITZ) develops high-brightness electron sources for modern FELs. With a 23 MeV, 1 nC beam at PITZ the experimental slice emittance characterization with the quadrupole scan technique is complicated by strong space charge effects. Combining the slit scan technique with a transverse deflecting cavity (TDS) allows for timeresolved emittance measurements of such a space-chargedominated beam. The first proof-of-principle results of slice emittance measurements at PITZ based on the ’TDS + slit scan’-technique are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO098

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paper received ※ 04 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO109

Electron Cloud Estimates for the Jefferson Lab EIC

sextupole, simulation, proton, dipole

563

K.E. Deitrick, V.S. Morozov, T. Satogata
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In this work, we present preliminary estimates for electron cloud build-up and saturation for the ion ring of the Jefferson Laboratory Electron-Ion Collider (JLEIC) currently under development. Using the baseline ion ring design, we study the impact of various operational parameters on the behavior of the electron cloud for a 100 GeV proton beam, including estimated tune shifts.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO109

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUPO112

Calculation of Electron Beam Dynamics in Four Accelerating Stations for JINR Linear Electron Accelerator LINAC-200

linac, solenoid, detector, acceleration

566

A. Sledneva, V. Aleksandrov, V.V. Kobets
JINR, Dubna, Moscow Region, Russia

In the Joint Institute for Nuclear Research a Test Stand with an electron beam generated by the linear accelerator LINAC-200 with the energy up to 200 MeV is being constructed to investigate properties of accelerating and semiconducting structures for advanced detectors, a radiation resistance of detectors based on gallium arsenide semiconductor, to study a free electron laser and to do other applied for work. The technical characteristics of the LINAC-200 accelerator make it possible to create an advanced system of test beams for scientific and methodological studies of detectors on its basis. Four accelerating stations with maximum beam energy up to 200 MeV are put into operation. The work is being carried out for experiments with electron test beams with energy up to 800 MeV. This work presents the calculation results of the magnetic field of the focusing solenoidal system and electron beam dynamics in accelerating stations. In addition, the results on the formation of the electron beam with optimal parameters to be captured in further accelerating sections.

Poster TUPO112 [1.176 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO112

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUPO119

A Diagnostics Box for the Linear Accelerator of Institute for Research in Fundamental Science (IPM)

linac, diagnostics, dipole, solenoid

581

S. Sanaye Hajari, M. Bahrami, H. Behnamian, S. Kasaei, H. Shaker
IPM, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

The IPM linac is an 8 MeV (up gradable to 11 MeV) electron linear accelerator under development at Institute for Research in Fundamental Sciences, Tehran, Iran. The design and construction of the linac is nearly finished and it is in the commissioning stage. The commissioning is planned in several phase of different energy ranging from 50 keV to 8 MeV. At each phase appropriate diagnostics is required in order to investigate the linac performance. A diagnostics box including a scintillator view screen, a dipole magnet, and a focusing solenoid is designed to diagnose the beam longitudinal and transverse parameters in wide range of energy. These parameters are the beam transverse profile, size, position, emittance and the energy spectrum.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO119

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUPO120

The Study of the Length and Shape of Beam in a High Power Electron Accelerator

radiation, extraction, industrial-accelerators, simulation

584

M. Salehi, F. Abbasi Davani, B.G. Ghasemi
Shahid Beheshti University, Tehran, Iran
F. Ghasemi, A.P. Poursaleh
NSTRI, Tehran, Iran

The output beam of a high-power linear accelerator, used for industrial purposes, is irradiated on products and scanning them. In order to improve the dosimetry of radiation which products received and to prevent loss of the attacked- beams to the edge of products, the exact evaluation of scanning length is necessary . One of the other challenges of the scanning beam is the lack of uniformity in dosimetry of received radiation . The scanning beam does not collide in parallel to the products, which is also a challenge to accelerator efficiency. To improve dosimetry of received radiation, the use of trajectory correction magnets is suggested. These magnets correct the beams that do not scan in parallel. Also, using the Monte Carlo code, the dosing rate of received radiation to products is simulated and compared in two non-uniform and uniform modes (corrected by trajectory correction magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO120

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TUPO127

Activities at the Linac4 Test Stand

emittance, rfq, linac, extraction

587

J.-B. Lallement, V. Bencini, S.B. Bertolo, F.D.L. Di Lorenzo, J. Lettry, A.M. Lombardi, C.M. Mastrostefano, D. Noll, M. O’Neil
CERN, Geneva, Switzerland

Linac4, the new CERN H⁻ injector to the Proton Synchrotron Booster, has been commissioned and has delivered a beam intensity and quality calculated to be sufficient to produce the standard beams for LHC and the high intensity beams for ISOLDE when connected. The beam current is nevertheless half of what is foreseen and the problem has been identified at the low energy end, between the extraction and the matching to the RFQ. The Linac4 test stand is being used to address this issue by testing different extraction geometries and different plasma generators. A fast method to access the current in the RFQ acceptance has been put in place. This paper reports the results of the measurements obtained so far.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO127

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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WE1A03

Latest Results of CW 100 mA Electron RF Gun for Novosibirsk ERL Based FEL

cavity, gun, cathode, radiation

598

V. Volkov, V.S. Arbuzov, E. Kenzhebulatov, E.I. Kolobanov, A.A. Kondakov, E.V. Kozyrev, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, A.A. Murasev, V.K. Ovchar, V.M. Petrov, A.M. Pilan, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, S.S. Serednyakov, O.A. Shevchenko, S.V. Tararyshkin, A.G. Tribendis, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia

Continuous wave (CW) 100 mA electron rf gun for injecting high-quality 300-400 keV electron beam to the Energy Recovery Linac (ERL) driving the Novosibirsk Free Electron Laser (FEL) was developed, built, and commissioned in a diagnostics beam line. The rf gun consists of normal conducting 90 MHz rf cavity with a gridded thermionic cathode unit. Tests of the rf gun confirmed its design performance in strict accordance with numerical simulations. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the rf gun are presented. The commissioning experience is discussed. The latest beam results are reported.

Slides WE1A03 [2.829 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A03

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paper received ※ 14 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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WE1A05

SwissFEL Linac Commissioning Status, Current Performance and Future Plans

linac, FEL, experiment, operation

605

P. Craievich
PSI, Villigen PSI, Switzerland

SwissFEL, the hard x-ray free-electron laser facility at PSI, is in an advanced commissioning phase. The commissioning of the 5.8 GeV Linac started in 2016 and the first FEL pilot-experiments were performed at a reduced beam energy in the end of 2017. In 2018, it is foreseen to progressively increase the electron beam energy and photon energy up to the maximum design values, interleaved by several FEL pilot experiments. This paper gives an overview of the commissioning progress including the achieved machine performance and first operational experience.

Slides WE1A05 [10.370 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A05

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paper received ※ 18 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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WE1A06

Pulse-to-pulse Beam Modulation for 4 Storage Rings with 64 Pulsed Magnets

power-supply, controls, positron, linac

609

Y. Enomoto, K. Furukawa, T. Kamitani, F. Miyahara, T. Natsui, M. Satoh, K. Yokoyama, M. Yoshida
KEK, Ibaraki, Japan
H.S. Saotome
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

The KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is planned to inject electron and positron beams with energies from 2.5 GeV to 7 GeV pulse-by-pulse at 50 Hz into the dual ring SuperKEKB collider and two light source storage rings. As the beam quality requirement from SuperKEKB is demanding, the beam orbit and optics conditions have to be maintained precisely. To that end 64 newly designed pulsed magnets were installed. Quadrupole magnets with the inductance of 1 mH are driven by power supplies with pulses up to 330 A and 0.5 ms, which recover the energy stored in coils up to 65%. Orbit corrector magnets with the inductance of 3 mH are driven with bipolar pulsed power supplies up to 10 A. Those power supplies are controlled under the event-based synchronized controls and monitored pulse-by-pulse, and are confirmed to have the stability over weeks within 0.1%. The details of the design and the operational performance will be reported.

Slides WE1A06 [6.694 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A06

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TH1A01

First Ever Ionization Cooling Demonstration in MICE

emittance, experiment, detector, scattering

632

J.Y. Tang
IHEP, Beijing, People’s Republic of China

Funding: STFC, DOE, NSF, INFN, CHIPP and more
The Muon Ionization Cooling Experiment (MICE) at RAL has studied the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. This invited talk presents and discusses these results, and projects the future of ionization cooling.
Abstract submitted by the speakers bureau of the MICE Collaboration. If accepted, a member of the collaboration will be selected to present the contribution

Slides TH1A01 [6.524 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A01

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paper received ※ 19 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019

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TH1A03

High Brightness Electron Beams from Plasma-based Acceleration

plasma, acceleration, FEL, simulation

637

A. Marocchino, A. Biagioni, E. Brentegani, E. Chiadroni, M. Ferrario, F. Filippi, A. Giribono, R. Pompili, A.R. Rossi
INFN/LNF, Frascati (Roma), Italy
A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy

Funding: INFN-CNAF and CINECA for high performance computing resources. European Union Horizon 2020 programme N. 53782.
Plasma Wakefield acceleration is a promising new acceleration techniques that profit by a charged bunch, e.g. an electron bunch, to break the neutrality of a plasma channel to produce a wake where a trailing bunch is eventually accelerated. The quest to achieve extreme gradient conserving high brightness has prompted to a variety of new approaches and techniques. Most of the proposed schemes are however limited to the only plasma channel, assuming in the vast majority of cases, ideal scenarios (e.g. ideal bi-gaussian bunches and uniform density plasma channels). Realistic start-to-end simulations, from the photo-cathode to FEL via a high gradient, emittance and energy spread preserving plasma section, are mandatory for paving the way towards plasma-based user facilities.

Slides TH1A03 [25.814 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A03

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TH1A04

The Proton Driven Advanced Wake Field Acceleration Experiment (AWAKE) at CERN

plasma, proton, wakefield, acceleration

642

S. Döbert
CERN, Geneva, Switzerland

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wake field generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world’s first proton driven plasma wake field acceleration experiment. The experiment uses the 400 GeV proton beam from the SPS which travels through a 10 m long Rb-vapour plasma cell where it gets self-modulated and generates the plasma wake fields. Eventually an electron beam is injected externally to probe the wake-fields. AWAKE will has completed several experimental campaigns starting in 2016. Results from the initial characterization of the plasma cell and measurements of the seeded self-modulation of the proton beam will be presented. Experiments to accelerate externally injected electrons using the proton driven plasma wake fields will start in 2018 and first results will be reported.

Slides TH1A04 [4.787 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A04

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO004

Pulsed Operation of CEBAF for JLEIC Injection

cavity, injection, linac, beam-loading

682

J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
JLab Electron Ion Collider (JLEIC) is planning to use the recently upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The JLEIC electron injection requires 3-4µs long bunch trains with a 20-400ms spacing in between, resulting in uneven beam loading for the CW CEBAF. With the high beam current in JLEIC collider rings, the low duty factor of injection also requires to a very high pulsed beam current from CEBAF, exacerbating the transient beam loading issue. In this paper, we will present CEBAFs detailed pulsed operation scheme for JLEIC injection, as well as some experimental results at CEBAF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004

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paper received ※ 20 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO010

Novel Straight Merger for Energy Recovery Linacs

cavity, dipole, experiment, simulation

702

K.E. Deitrick, A. Hutton
JLab, Newport News, Virginia, USA
A.C. Bartnik, C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S.A. Overstreet
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO016

Investigation of 2D PBG Waveguides for THz Driven Acceleration

GUI, acceleration, impedance, photon

714

A. Vint, R. Letizia
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Letizia
Lancaster University, Lancaster, United Kingdom

Funding: Work supported by the STFC PhD Studentship
Novel accelerating techniques that overcome the limitations of conventional RF technology are receiving significant interest. Moving from RF to the THz frequency range, higher gradient of acceleration of high energy beams can be achieved in miniaturised structures. Moreover, with respect to the optical frequency range, the THz regime allows for larger structures and better beam quality to be obtained. In this paper, we investigate the use of a 2D photonic bandgap (PBG) waveguide for THz driven electron acceleration. In accelerator applications, the properties of PBG waveguides can be exploited to damp higher order modes and offer low-loss dielectric confinement at high frequency. In particular, 2D PBG waveguides offer a good compromise between manufacturability, total photonic bandgap confinement, and ease of parallel illumination. The structure here proposed is optimised for maximum bandgap and single mode operation. Dispersion characteristics of the accelerating mode are studied to achieve the best compromise between high accelerating field and effective accelerating bandwidth, given a ~10% bandwidth of the THz driving pulse.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO016

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO017

Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment

kicker, injection, site, experiment

717

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

Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216.
A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase.
*H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO018

Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises

controls, linac, cavity, collider

721

V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase
SLAC, Menlo Park, California, USA
A. Grudiev
CERN, Geneva, Switzerland
H. Zha
TUB, Beijing, People’s Republic of China

Accelerating structures are usually manufactured by precision turning of individual cells combined with precision milling for complex parts such as rf power couplers. These multiple parts are staked and brazed into a complete structure. We consider an alternative approach: precision milling of multiple cells and couplers into metal blocks that comprise halves or quadrants of the complete structure. We successfully produced a 12~GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype using this method. A previous prototype was designed as an open structure with a gap between cell irises. Here we describe a different approach, an accelerating structure which is brazed through irises. It is based on a multi-cell traveling wave structure designed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises structure was built at SLAC for high power tests at CERN. Here we describe the details of this process.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO018

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paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO020

Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator

SRF, GUI, resonance, acceleration

725

Y.T. Yuan
HUST, Wuhan, People’s Republic of China
K. Fan
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
Y. Jiang
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA

Funding: the National Natural Science Foundation of China
The cyclotron auto-resonance accelerator (CARA) is a novel concept of accelerating continuous gyrating charged-particle beams to moderately or highly relativistic energies, which can be used as the high power microwave source and applied in environment improvement area, particularly in the flue gas pollution remediation. In CARA, the continuous-wave (CW) electron beam follows a gyrating trajectory while undergoing the interaction with the rotating TE-mode rf field and tapered static magnetic field. In the process of gyrating acceleration, the phase synchronization with the rf field is automatically maintained, so to speak, with auto-resonance. Simulation models are constructed to study the effect of rf field and static magnetic field on electron beam in CARA, where the beam energy, trajectory and velocity component are analysed. The simulation results match reasonably well with theoretical predication, which sets up a solid foundation for future designs of CARA.

Poster THPO020 [1.448 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO020

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paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO021

Research on X Ray Characteristics Produced by Highenergy Picosecond Electron Beam Shooting

target, photon, linac, radiation

729

X.D. Zhang, X.P. Ouyang, B. Sun, X.J. Tan, X.F. Weng
NINT, Xi’an, People’s Republic of China

Funding: Supported by National Natural Science Foundation of China(11375142)
The X ray sources based on electron linac can produce X-rays with high energy, concentrated directions, and strong penetrating power, which have been widely applied in various fields. An electronic linear accelerator which has been built at present can provide an electron beam with energy of 120 MeV and pulse width of picosecond. The electron beam shooting at the metal targets can produce ultra-fast pulsed X-rays in the order of picosecond. In this paper, the pulse X ray characteristics are studied through simulating electron beam shooting at four metal targets with different thickness of Au, Ta, U, W and Pb by MCNPX program. The calculation shows that the X-rays can reach about 1010p/pulse and the pulse width can reach about picosecond level, when the pulsed electron beams with energy of 120 MeV ,charge of 0.5nC and pulse width of picosecond shooting at Ta targets. The yield and time width of pulsed X-rays are related to the diameter and thickness of the target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO021

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paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO069

The Electromagnetic Optimization of TE-sample Host Cavity at IMP

cavity, SRF, niobium, linac

852

S.C. Huang, Y. He, T. Tan, S.X. Zhang
IMP/CAS, Lanzhou, People’s Republic of China

As a part of the research and development work of thin-film materials for superconducting radio frequency(SRF) application in future accelerators at IMP, a 3.9GHz TE sample host cavity is being developed for the purpose of characterizing the RF Property and the loss mechanism of thin-film materials, which operates in the TE011 mode and accommodates disk sample with 110mm diameter, theoretically, the maximum magnetic field on sample surface will go up to 100mT, the resolution of surface resistance on sample will below nOhm by using thermometry technique( T-Mapping). In this paper, the electromagnetic optimization result of TE-sample host cavity will be presented, and the design consideration of hook tip style coupler and T-mapping system are also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO069

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO079

RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations

cavity, diagnostics, emittance, operation

866

V.V. Paramonov
RAS/INR, Moscow, Russia
K. Flöttmann
DESY, Hamburg, Germany

For diagnostic of longitudinal distribution of electrons in unique REGAE bunches is applied a specially developed deflecting structure with minimized level of aberrations in the field distribution and improved RF efficiency. Short deflecting cavity was constructed and installed now in REGAE beam line. The cavity is tested at operational level of RF power. The main distinctive features of the cavity are mentioned and obtained results are reported.

Slides THPO079 [1.803 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO082

Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement

cavity, simulation, FEL, coupling

872

J. Bai, Q.S. Chen, K. Fan
HUST, Wuhan, People’s Republic of China

Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.

Poster THPO082 [0.484 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO084

BPM Time of Flight Measurements for Setting-up the RF Cavities of the CERN Linac4

linac, cavity, DTL, simulation

879

M. Bozzolan
CERN, Geneva, Switzerland

The newly constructed H⁻ LINAC4 at CERN has recently completed its first extended reliability run. It is equipped with Beam Position Monitors (BPMs) based on shorted-stripline pick-up electrodes to measure both position and Time of Flight (ToF). The ToF, in turn used to calculate the kinetic energy of the beam, is determined through signal phase shift measurements between pairs of BPMs. ToF measurements are performed by scanning of the phase of the RF injected into the cavities to find the nominal RF settings for optimal beam acceleration. This paper focuses on the technical aspects of the ToF measurement as well as on the results obtained during beam commissioning and their comparison with beam dynamics simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO084

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO086

Beam Loss and Average Beam Current Measurements Using a CWCT

proton, instrumentation, electronics, diagnostics

882

F. Stulle, H. Bayle, J.F. Bergoz, T. Delaviere, L. Dupuy
BERGOZ Instrumentation, Saint Genis Pouilly, France
P. Forck, M. Witthaus
GSI, Darmstadt, Germany
D. Vandeplassche
SCK•CEN, Mol, Belgium
J.X. Wu
IMP/CAS, Lanzhou, People’s Republic of China

The CWCT is a novel instrument adapted to an accurate average current determination of bunched CW beams or macro pulses. By combining a high-droop current transformer with novel electronics for signal analysis, an output signal bandwidth of DC to about 500kHz and a current resolution down to the micro-ampere level are achieved. Beam current fluctuations are followed within microseconds, permitting fast detection of beam loss. These characteristics render the CWCT an ideal instrument for HPPAs, for example ADS linacs, and other proton or ion accelerators. We present the CWCT principle and the CWCT performance achieved in beam experiments at UNILAC, GSI.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO086

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO091

90 kW Solid-state RF Amplifier with a TE011-mode Cavity Power-combiner at 476 MHz

cavity, controls, FEL, power-supply

889

Y. Otake, T. Asaka, T. Inagaki
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Aizawa, K. Nagatsuka, T. Okuyama, K. Sato, H. Yamada
Nihon Koshuha Co. Ltd, Yokohama, Japan

Solid-state RF amplifiers, which have long lifetimes and small failures, are the recent trend of reliable and stable high-power rf sources for particle accelerators. Hence, we designed a 90kW solid-state amplifier with an extreme low-loss TE011 mode cavity (Q0=100, 000) power-combiner operated at 476 MHz and a 6 us pulse width. Developing this amplifier is for replacement of an IOT rf amplifier, at the X-ray free-electron laser, SACLA. In SACLA, highly RF phase and amplitude stabilities of less than 0.02 deg. and 10^-4 in rms are necessary to stable lasing within a 10 % intensity fluctuation. The amplifier comprises a drive amplifier, a reentrant cavity rf power divider, 100 final amplifiers with a 1 kW output each and a TE011 mode cavity combiner. Water-cooling within 10 mK and a DC power supply with a noise of less than -100 dBV at 10 Hz for the amplifier is necessary to realize the previously mentioned stabilities. Based on the test results of the amplifier, the above-mentioned specifications with the extreme low-loss are promising. The amplifier also allows us to operate in pulsed and CW rfs for linacs and ring accelerators. We report the performance of the 90kW amplifier.

Slides THPO091 [1.750 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO091

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paper received ※ 06 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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THPO097

Recent Results for Study of Ceramic and Copper Plating for Power Couplers

survey, target, controls, SRF

905

Y. Yamamoto, E. Kako, S. Michizono
KEK, Ibaraki, Japan
E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
Y. Okii
Nomura Plating Co, Ltd., Osaka, Japan

KEK has conducted a survey to select an optimum ceramic after withdrawal by a domestic manufacturing company two years ago. For this selection, there are four important items on the properties of ceramic; that is, relative permittivity, dielectric loss tangent, surface and volume resistance, and secondary electron emission coefficient. For measurements of these parameters, five kinds of ceramic samples supplied from three companies were measured using three kinds of measurement systems. For measurement of secondary electron emission, scanning electron microscope (SEM) with beam blanking system was used. On the other hand, residual resistivity ratio (RRR) for copper plating, which is the most important item for quality control, has also been carried out while changing plating thickness and acid temperature. In this report, the recent results for these studies will be presented in detailed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO097

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO100

Development of a 1.5 GHz High-power CW Magnetron for SRF Accelerator

simulation, cavity, SRF, coupling

908

L. Wenliang
College of Engineering and Applied Sciences for Nanjing University, Nanjing, People’s Republic of China
S. An, Y.J. Ke, S. Lingbin, Z. Pengjiao, L. Youchun, L. Zhao, B.Z. Zhou
PLAI, Nanjing, People’s Republic of China
J.Z. Li, L.P. Zhang, Hou, R. Rui
ADS, Jiangsu Province, People’s Republic of China

An 1.5 GHz, 13.5 kW CW high-power magnetron for a superconducting RF accelerator has been developed by Andesun Technology Group Co., Ltd. with Nanjing Sanle Electronic Information Industry Group Co., Ltd., in order to replace the klystron, that could reduce the power source cost to about one-third. The cavity, output power antenna and coupling door-nob have been optimized by using CST Studio. Testing results have shown that the resonance frequency and output power have met the requirements, and the efficiency of the magnetron is higher that 78.45%.

Poster THPO100 [0.574 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO100

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO102

Design Studies of Output Window for CEPC Klystron

klystron, multipactoring, simulation, operation

911

Z.J. Lu, Y.L. Chi, S. Fukuda, G. Pei, S. Pei, S.C. Wang, O. Xiao, U. N. Zaib, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
S. Fukuda
KEK, Ibaraki, Japan

A high power and high efficiency klystron of the 650MHz, 800kW CW klystron for the Circular Electron Positron Collider (CEPC) is designed and developed at IHEP. This paper presents the design and simulation for the high power coaxial window for it. Plan of the hot test (high power testing before installing to the klystron) are also described. Simulation software of CST, ANSYS and Multipac 2.1 are used for design of window microwave structure, thermal analysis and multipacting effects. We obtained the good simulation results successively; the coaxial window S-parameter analysis, has revealed a low reflection at the operating frequency of 650 MHz. The thermal simulation shows a good temperature distribution under the cw 800kW propagation; maximum temperature has been found to be 33 °C at ceramic with water cooling in the inner and outer conductor. The multipacting at the window is possible source of the failure and it is shown that multipacting has less chance to be happened on the surface of ceramic.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO102

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paper received ※ 12 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019

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THPO124

Design of Pulsed HV and RF Combined Gun System Using Gridded Thermionic-Cathode

gun, emittance, cavity, cathode

949

T. Asaka, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
Y. Otake
JASRI, Hyogo, Japan
T. Taniuchi
JASRI/SPring-8, Hyogo-ken, Japan

In recent state-of -arts accelerators like an X-ray free electron laser, the electron beam performance of a linear accelerator demands a low emittance of ~ 2mm mrad. To obtain the low-emittance, such a 500kV thermionic-gun at SACLA and a photocathode rf gun generating 0.5~1MeV electron beams had been developed. Although the photocathode rf gun is compact, it is necessary to prepare a highly stabilized, large and complicated laser system. The 500-kV thermionic-gun of SACLA injector has also to prepare a technically difficult and large high voltage system. Hence, we propose a low-emittance gun system with a low-voltage and grid-loaded 50kV thermionic gun and a 238MHz rf cavity to overcome the complicated difficulty, as extension of the established technology. This system quickly accelerates the electron up to 500keV to preserve the low emittance and to cancel a grid focusing effect by the space charge force of the beam. By using a particle tracking code, we obtained the optimum voltage parameters of the grid and the 238MHz rf for obtaining the above-mentioned low emittance. In this paper, we present a numerical feasibility study to realize the low-emittance gun system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO124

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO132

Study of the Electron Beam Transfer Line for the AWAKE RUN II Experiment at CERN

plasma, experiment, simulation, emittance

962

S.Y. Kim, M. Chung
UNIST, Ulsan, Republic of Korea
M. Dayyani
IPM, Tehran, Iran
S. Döbert
CERN, Geneva, Switzerland

Proton Beam-Driven Plasma Wakefield Accelerator (PBD-PWFA) has been actively investigated at CERN within the AWAKE experiments to study the electron beam acceleration using plasma wake fields of the order of GV/m. In the AWAKE RUN 1 experiment an electron beam with an energy of 19 MeV and a bunch length of 2.2 ps rms has been used for the first demonstration of electron beam acceleration in the plasma wake fields. It has been observed that the energy gain of the electron beam is up to 2 GeV, and electron capture efficiency is few percent. Higher capturing efficiency and emittance preservation could be achieved by making the electron beam short enough to be injected only into the acceleration and focusing phase of the plasma wake fields. The electron accelerator needs to be upgraded for AWAKE RUN 2 experiments to obtain a bunch length less than 100 fs which corresponds to a quarter of the plasma wavelength. Planned electron beam parameters for the AWAKE RUN 2 are a beam charge of 100 pC, and a beam energy larger than 50 MeV. In this paper, we show the electron beam parameters for RUN 2, and the parameters of the transfer line such as Twiss parameters, beam envelope, and emittance.
UNIST, Ulsan, 44919, Korea
Institute For Research in Fundamental Sciences, 19395-5531, Tehran, Iran
CERN, Geneva 1211, Switzerland

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO132

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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FR1A02

Bunch Length Measurements using Transverse Deflecting Systems

FEL, diagnostics, emittance, beam-diagnostic

972

M. Hüning
DESY, Hamburg, Germany

Shorter and shorter bunch lengths (some 10 fs) require sophisticated bunch length measurent devices. Free electron lasers - but not only - use transverse deflecting systems. Employing suitable diagnostic tools measurements are not limited to bunch lengths but can be extended to longitudinal profiles and phase-space distributions, and slice emittances. Not only do successfully operated systems aid the commissioning and operation of FELs but they allow control over more sophisticated phase-space manipulations. The design and construction of such systems, actually operated at different RF frequencies, includes cavity design and fabrication, powerful RF systems, low level RF control, beam lines, diagnostics, and data analysis.

Slides FR1A02 [6.054 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A02

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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FR1A06

Pulse-by-Pulse Beam Parameter Switching of High-Quality Beams for Multi-Beamline Operation at SACLA

FEL, controls, laser, optics

988

H. Maesaka, T. Fukui, T. Hara, Y. Otake
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
T. Hasegawa, O. Morimoto, Y. Tajiri, S. Tanaka, M. Yoshioka
SES, Hyogo-pref., Japan
N. Hosoda, S. Matsubara, T. Ohshima
JASRI/SPring-8, Hyogo-ken, Japan
C. Kondo, M. Yamaga
JASRI, Hyogo, Japan

The main linac of the X-ray free electron laser (XFEL), SACLA, provides electron beams to two XFEL beamlines and a beam transport line to the SPring-8 storage ring. In order to utilize these beamlines at the same time, a kicker magnet was installed into the switch yard and electron beams with a 60 Hz repetition rate can be distributed to these beamlines pulse-by-pulse. Since a beam energy and an optimum bunch length are usually different for each beamline, the operation condition of each acceleration unit, such as the rf phase, the trigger permission, etc., has to be changed pulse-by-pulse. Even in that case, the electron beam quality, such as 1 mm mrad normalized emittance, 10 fs bunch length, 10 kA peak current, etc., must not be deteriorated. At first, we developed a parameter control software that was able to manage two XFEL beamlines with an equal repetition rate. Different energy beams with sufficient quality for lasing were successfully distributed to the two XFEL beamlines and the XFEL performances of both beamlines were optimized simultaneously. The development status of a new parameter switching system with an arbitrary sequence of the destinations will also be reported.

Slides FR1A06 [6.179 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A06

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paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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