Keyword: emittance
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MO2A04 Compact SRF Linac for High Brilliance Inverse Compton Scattering Light Source electron, laser, brilliance, 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 icon 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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MOPO007 The Developing of the Beam Injection Section with Laser Source and S-Band Electron RF Gun for SuperKEKB Project laser, gun, electron, MMI 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, electron, cathode, 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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MOPO027 Photocathode Laser Pulse Shaping for Improved Emittance laser, cathode, electron, gun 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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MOPO029 Physics design and dynamic simulation of a C-band photocathode electron gun for UEM electron, gun, 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 icon 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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MOPO096 Realistic Modeling of MEBT for the New LANSCE RFQ Injector DTL, quadrupole, rfq, simulation 211
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  The new RFQ-based proton injector at LANSCE requires a specialized medium-energy beam transfer (MEBT) after the RFQ at 750 keV due to a following long (~3 m) existing common transfer line that also transports H− beams to the DTL entrance. The horizontal space for MEBT elements is limited because two beam lines merge at 18-degree angle. The MEBT includes two compact quarter-wave RF bunchers and four short quadrupoles with steerers, all within the length of about 1 m. The beam size in the MEBT is large, comparable to the beam-pipe aperture, hence non-linear 3D fields at large radii and field-overlap effects become important. With CST Studio codes, we calculate buncher RF fields and quadrupole and steerer magnetic fields, and use them for particle-in-cell beam dynamics modeling of MEBT with realistic beam distributions from the RFQ. Our results indicate significant emittance growth in MEBT not predicted by the standard beam dynamics codes. Its origin is traced mainly to the quadrupole edge fields; the buncher RF fields also contribute noticeably. Proposed design modifications improve the MEBT performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO096  
About • paper received ※ 10 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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MOPO127 Recent Results from MICE on Multiple Coulomb Scattering and Energy Loss scattering, simulation, detector, radiation 267
 
  • J.Y. Tang
    IHEP, Beijing, People’s Republic of China
  • J.C. Nugent
    University of Glasgow, Glasgow, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, CHIPP and more
Multiple Coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, available simulation codes (GEANT4, for example) are known to overestimate the scattering of muons in low Z materials. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in the fall of 2015 with the absorber vessel filled with xenon and in the spring of 2016 using a lithium hydride absorber. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are all compared with the Bethe-Bloch formula and with the predictions of various models, including the default GEANT4 model.
Submitted by the MICE speakers Bureau. If accepted a member of the collaboration will be selected for the mission 		 
poster icon Poster MOPO127 [0.842 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO127  
About • paper received ※ 19 September 2018       paper accepted ※ 31 October 2018       issue date ※ 18 January 2019  
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MOPO129 Recent Results from the Study of Emittance Evolution at MICE detector, solenoid, experiment, lattice 270
 
  • W.B. Liu
    IHEP, Beijing, People’s Republic of China
  • V. Blackmore, C. Hunt
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, CHIPP and more
The Muon Ionization Cooling Experiment (MICE) has measured the evolution of emittance due to ionization energy loss. Muons were focused onto an absorber using a large aperture solenoid. Lithium-hydride and liquid hy- drogen-absorbers have been studied. Diagnostic devices were placed upstream and downstream of the focus, ena- bling the phase-space coordinates of individual muons to be reconstructed. By observing the properties of ensem- bles of muons, the change in beam emittance was meas- ured. Data taken during 2016 and 2017 are currently un- der study to evaluate the change in emittance due to the absorber for muon beams with various initial emittance, momenta, and settings of the magnetic lattice. The current status and the most recent results of these analyses will be presented.
Submitted by the MICE speakers Bureau. If accepted a member of the collaboration will be selected for the mission 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO129  
About • paper received ※ 30 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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TU2A01 First Acceleration of Heavy Ion Beams with a Superconducting Continuous Wave HIM/GSI CW-linac cavity, linac, heavy-ion, acceleration 297
 
  • W.A. Barth, K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  
  First acceleration of heavy ion beams with a superconducting continuous wave HIM/GSI CW-Linac After successful RF-testing of a new superconducting Linac RF-cavity at GSI Helmholtzzentrum für Schwerionenforschung and a short commissioning and ramp up time of some days, this 15-gaps Crossbar H-cavity accelerated first time heavy ion beams with full transmission up to the design beam energy. The design acceleration gain of 3.5 MV inside a length of less than 70 cm has been verified with heavy ion beam of up to 1.5 particle mkA. The measured beam parameters show a nice beam quality. The machine commissioning with beam is a milestone of the R&D work of Helmholtz Institute Mainz and GSI in collaboration with Goethe University Frankfurt in development of the superconducting heavy ion continuous wave linear accelerator CW-Linac.  
slides icon Slides TU2A01 [3.385 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU2A01  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TU2A03 Layout of the New FAIR Post-stripper DTL for Intense Heavy Ion Beams DTL, quadrupole, operation, cavity 303
 
  • S. Mickat, X. Du, P. Gerhard, L. Groening, M. Heilmann, M. Kaiser, A. Rubin, V. Srinivasan, W. Sturm
    GSI, Darmstadt, Germany
  
  The new post-stripper DTL at GSI shall accelerate uranium beams with space charge induced tune depressions of up to 37% to 11.4 MeV/u. Emittance dilution must be kept below few percent. However, the layout must also allow for delivery of lightest ions to just 3.0 MeV/u. This broad-banded range of requirements imposes huge challenges on the layout and fabrication especially of the cavities and drift tube magnets.  
slides icon Slides TU2A03 [4.777 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU2A03  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TU1P01 Extreme High Brightness Electron Beam Generation in a Space Charge Regime cavity, electron, 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 icon 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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TUPO005 Initial Beam Commissioning of LEAF at IMP rfq, MMI, ECR, acceleration 332
 
  • Y. Yang, W.P. Dou, X. Fang, Y.H. Guo, H. Jia, L. Jing, X.J. Liu, L. Lu, W. Lu, W. Ma, L.T. Sun, L.P. Sun, W. Wei, H.W. Zhao, Y.H. Zhai
    IMP/CAS, Lanzhou, People’s Republic of China
  
  A Low Energy intense-highly-charged ion Accelerator Facility (LEAF), which mainly includes an ECR ion source, LEBT and an 81.25 MHz RFQ, was designed to produce and accelerate heavy ions, from helium to uranium with A/Q between 2 and 7, to the energy of 0.5 MeV/u. The typical beam intensity is designed up to 2 emA CW for the uranium beam. The facility has been successfully commissioned with He+ (A/Q=4) and N2+ (A/Q=7) beams and accelerated the beams in the CW regime to the designed energy of 0.5 MeV/u. Beam properties and transmission efficiencies were measured, indicating a good consistency with simulated data. After having briefly recalled the project scope and parameters, this paper describes the beam commissioning strategy and detailed commissioning results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO005  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO011 Upgrade of Heavy Ion Injector I-3 at ITEP acceleration, heavy-ion, laser, bunching 346
 
  • N.N. Alexeev, P.N. Alekseev, V. Andreev, T. Kulevoy, A.D. Milyachenko, V.I. Nikolaev, Yu.A. Satov, A. Shumshurov, A. Zarubin
    ITEP, Moscow, Russia
  
  Heavy ion injector I-3 represents two-gap 2.5 MHz resonator with accelerating voltage 2x2 MV. It‘s used with laser ion source for acceleration of heavy ions in wide range of charge to mass ratio. As a result of modernization, injector structure will be supplemented by the second two-gap resonator, rf voltage will be increased to 3x4 MV and accelerated beam structure has to be improved by increasing accelerating frequency to 5 MHz. Design features of upgraded linac and peculiarity of beam dynamics for different types of ions are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO011  
About • paper received ※ 03 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO016 High Frequency RFQ Design and LEBT Matching for the CERN TwinEBIS Ion Source rfq, gun, space-charge, simulation 358
 
  • V. Bencini, J.-B. Lallement, A.M. Lombardi, H. Pahl, J. Pitters, F.J.C. Wenander
    CERN, Geneva, Switzerland
  • M. Breitenfeldt
    AVO-ADAM, Meyrin, Switzerland
  • A.I. Pikin
    BNL, Upton, Long Island, New York, USA
  
  An Electron Beam Ion Source (EBIS) is being developed at CERN for production of highly charged ions, for instance fully stripped 12C. The focus has so far been on the electron gun design, aiming for a high current compression, which results in a rapid ionisation process and thereby high repetition rate. Initial commissioning tests of such an electron gun, the so-called MEDeGUN, have already been performed and we are now in the process of designing a multi-purpose ion extraction and diagnostics line. The Low Energy Beam Transport (LEBT) line will transport the ions into the downstream Radio Frequency Quadrupole (RFQ) with a nominal energy of 15 keV/u. The 750 MHz RFQ is designed to accelerate ions from 15 keV/u up to the final energy of 2.5 MeV/u. After the RFQ design was finalized and its acceptance calculated, the beam matching to the RFQ was studied, finding a set of parameters for the LEBT that maximize the transmission through the RFQ. Details of the RFQ design, of the LEBT matching procedure and its final results are illustrated in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO016  
About • paper received ※ 11 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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TUPO078 Extension of Busch’s Theorem to Particle Beams solenoid, experiment, cathode, electron 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 icon 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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TUPO079 Numerical and Experimental Study of H− Beam Dynamics in J-PARC LEBT rfq, MMI, linac, solenoid 519
 
  • T. Shibata, K. Ikegami, Y. Liu, K. Ohkoshi, M. Otani
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • A. Miura, H. Oguri, K. Shinto
    JAEA/J-PARC, Tokai-mura, Japan
  • F. Naito, K. Nanmo, A. Takagi
    KEK, Tokai, Ibaraki, Japan
  
  Negative hydrogen ion (H−) beam dynamics in J-PARC Low Energy Beam Transport (LEBT) has been investigated by numerical modeling which calculates particle transport with effect of space charge and collision processes. Understandings of H− beam transport in LEBT is important for high transmission rate from Ion Source (IS) to Radio Frequency Quadrupole (RFQ) in J-PARC in higher beam current in future. In 2017, 45 mA beam current of H− has been extracted from IS in J-PARC user operation which has been increased from 30 mA in last 2 years. The beam current is planned to be increased to 50 mA in the next upgrade. As the beam current increase, IS/LEBT commissioning becomes more difficult because of the higher space charge (SC). Especially in J-PARC, vacuum pressure is around 10-5 Pa by 15 mmf orifice located in the center of LEBT. The orifice prevents residual gas injection from IS to LEBT/RFQ and thus produces stronger SC effect. In the presentation, numerical results are compared with actual results from J-PARC Linac beam commissioning. A comparison of the results shows that location of the 15 mmf orifice results in two peaks of RFQ transmission rate against SOL currents.  
slides icon Slides TUPO079 [0.968 MB]  
poster icon Poster TUPO079 [1.699 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO079  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO083 Beam Dynamics for the FAIR p-Linac Ladder RFQ rfq, linac, simulation, ion-source 522
 
  • M. Syha, U. Ratzinger, M. Schuett
    IAP, Frankfurt am Main, Germany
  
  After the successful measurements with a 0.8 m prototype a 3.3 m Ladder-RFQ is under construction at IAP, Goethe University Frankfurt. It is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-Linac at FAIR. Along the acceleration section modulation parameter, aperture and synchronous phase all course (quasi-)linear, which differentiates this design approach from other designs developed at IAP. The ratio of transversal vane curvature radius to mid-cell radial aperture as well as the vane radius itself are constant, which favors a flat voltage distribution along the RFQ. This was verified by implantation of the modulated vane geometry into MWS-CST RF field simulations. The development of adequate beam dynamics was done in close collaboration with the IAP resonator design team. The Los Alamos RFQGen-code was used for the RFQ design and the beam dynamics simulations.  
poster icon Poster TUPO083 [0.932 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO083  
About • paper received ※ 12 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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TUPO085 Modelling of Beam Parameters of RF Linac for GBS-ELI-NP linac, simulation, quadrupole, gun 528
 
  • P.S. Tracz
    IFIN-HH, Bucharest - Magurele, Romania
  
  The Gamma Beam System at the ELI-NP (Extreme Light Infrastructure - Nuclear Physics) currently being constructed in Magurele/Bucharest, Romania will be a high-brilliance advanced source of gamma rays based on laser Compton back-scattering. For a successful operation of the GBS a high brightness low emittance electron beam is of crucial importance. The warm RF linac is designed in two stages - one with the beam up to 300 MeV, and another one about 720 MeV. The S-band photo-injector is combined with a C-band linac. The beam is transported by transfer lines to the interaction points. In this paper we report the results of computer simulations of the electron beam transport in the low energy linac and transfer line up to the low energy interaction point (IP1). The simulation model makes it possible to predict the beam parameters to be recuperated in case of failure of any magnetic or accelerating elements as well as it enables to determine the optimal parameters of replaced components. It will be used for the development of the Gamma Beam System in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO085  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO093 Excitation of Millimeter Wavelength Cavity Structure cavity, gun, cathode, simulation 543
 
  • M.V. Arsentyeva
    NSU, Novosibirsk, Russia
  • A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov
    BINP SB RAS, Novosibirsk, Russia
  
  Excitation of millimeter wavelength cavity structure In this work excitation of W-band structure is studied. The structure consists of cylindrical cavities with the operating frequency of about 96 GHz. We plan to excite the structure by short bunches from the photocathode RF gun. In order to choose structure geometry and beam duration, we performed estimations and simulations; induced voltage was also estimated. Taking into account feasible parameters of the photocathode RF gun such as beam size and emittance, we studied exciting beam transverse dynamics to define its other characteristics (energy and charge). To lead the beam from the whole structure, focusing is needed. After estimation of required magnetic field, we considered possibility of focusing with help of permanent magnets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO093  
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 electron, 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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TUPO106 Mathematical Principle and Numerical Reconstruction in Real Space Measurement with a Rotating BPM pick-up, diagnostics, beam-diagnostic, instrumentation 560
 
  • P. Jiang, Y. He, Z.J. Wang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  It is difficult to measure beam profiles and monitor the beam during beam supply for high intensity high power accelerators. Based on the button pick-ups, the mathematical principle of a rotating BPM is proposed. SVD method is used to reconstruct the beam in x-y real space, and the basic parameters used in beam reconstruction are argued. The beam distribution in x-y real space is reconstructed well and compared to the reference beam. The beam reconstruction is sensitive to the electrode radius. The meshing and the grid numbers in the solution window have an import effect on the beam reconstruction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO106  
About • paper received ※ 12 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TUPO115 Beam Parameters Measurement and Correction in CSNS Linac linac, MMI, DTL, injection 576
 
  • Z.P. Li, Y. Li
    IHEP, Beijing, People’s Republic of China
  • J. Peng
    CSNS, Guangdong Province, People’s Republic of China
  
  All the beam parameters of China Spallation Neutron Source (CSNS) linac had achieved the acceptance goals in January 2018 after a 2-year commissioning. Parameters of the H− beam were carefully studied and corrected. Beam energy was measured and the energy dispersion are reduced. Transverse emittance are obtained by different tools and methods. Linear optics measurements and corrections were carried out under varied beam energies and peak intensities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO115  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO116 Particle Dynamics Optimization in DTL cavity, focusing, quadrupole, DTL 579
 
  • I. Skudnova
    Saint Petersburg State University, Saint Petersburg, Russia
  
  The research concerns ion dynamics in linear accelerators with drift tubes (DTL). Permanent quadrupole magnets are placed inside some of the drift tubes. Frequency of the field is 432 MHz. Electromagnetic fields and particle dynamics in the cavity are calculated using Comsol Multiphysics software. The input energy of the beam is 6 MeV, output 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). The considered parameters are drift tubes radii, cavity diameter, gradient of the magnetic field from quadrupoles inside drift tubes and focusing lattice. Effectiveness is estimated by the emittance growth.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO116  
About • paper received ※ 14 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO127 Activities at the Linac4 Test Stand rfq, linac, electron, 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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WE2A01 First Acceleration at FRIB rfq, MMI, cryomodule, linac 615
 
  • G. Pozdeyev
    FRIB, East Lansing, Michigan, USA
  
  FRIB is now moving to commissioning interleaved with installation. The ECR, low energy transport and RFQ have been commissioned with beam By the time of the conference the 4K cryogenic system and first three beta 0.041 QWR cryomodules will be commissioned with first cold acceleration. The talk would focus on the hardware and beam performance.  
slides icon Slides WE2A01 [11.425 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A01  
About • paper received ※ 17 September 2018       paper accepted ※ 09 October 2018       issue date ※ 18 January 2019  
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WE2A04 Commissioning of New SARAF RFQ and Design of New Linac rfq, linac, proton, operation 626
 
  • A. Perry, D. Berkovits, H. Dafna, B. Kaizer, J. Luner, J. Rodnizki, A. Shor, I. Silverman, L. Weissman
    Soreq NRC, Yavne, Israel
  • A. Bechtold, P. Niewieczerzal
    NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
  • R.D. Duperrier, G. Ferrand, B. Gastineau, M. Jacquemet, C. Madec, N. Pichoff, D. Uriot
    CEA/IRFU, Gif-sur-Yvette, France
  • S. Ladegaillerie, Th. Plaisant
    IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France
  
  Status of the CEA desing of the future Saraf linac (title to be revised)  
slides icon Slides WE2A04 [7.096 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A04  
About • paper received ※ 17 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TH1A01 First Ever Ionization Cooling Demonstration in MICE experiment, detector, scattering, electron 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 icon 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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TH1P01 Commissioning of CERN LINAC4 linac, MMI, injection, proton 658
 
  • A.M. Lombardi
    CERN, Geneva, Switzerland
  
  This talk reviews the commissioning effort of CERN’s new H− linear accelerator, Linac4, which is presently undergoing a beam quality and reliability run. Linac4 will be connected to the LHC proton injector chain during the next long LHC shutdown (LS2) and will then replace the 50MeV proton Linac2.  
slides icon Slides TH1P01 [4.591 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1P01  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO001 Design Study on CEPC Positron Damping Ring System damping, injection, linac, positron 672
 
  • D. Wang, Y.L. Chi, J. Gao, D.J. Gong, C. Meng, G. Pei, J.R. Zhang
    IHEP, Beijing, People’s Republic of China
  
  The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of linac and hence reduce the beam loss in the booster. Before damping ring, an energy spread compression structure is designed to match the RF acceptance of damping ring. A longitudinal bunch length control is also necessary to meet the energy spread requirement in the linac by a bunch compressor system after the damping ring. Both designs for damping ring and energy/bunch compressors are discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO001  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO005 High Aspect Ratio Beam Generation with the Phase-space Rotation Technique for Linear Colliders gun, collider, simulation, linear-collider 685
 
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • J.G. Power
    ANL, Argonne, Illinois, USA
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • M. Washio
    RISE, Tokyo, Japan
  • H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  Funding: This work is partly supported by Grant-in-Aid for Scientific Research (B) and US-Japan Science and Technology Cooperation Program in High Energy Physics.
Linear colliders is the only way to realize e+ e− collision at higher energy beyond the limit of ring colliders by the huge synchrotron radiation energy loss. In the linear collider, the beam current should be much smaller comparing to the ring collider to save the required electricity. A way to realize an enough luminosity with the small beam current and less energy spread by Beamstrahlung, is collision in flat beam. This high aspect ratio beam can be made by phase-space rotation technique instead of the conventional way with DR (Damping Ring). We present a simulation of this technique and pilot experiments at KEK-STF and ANL WFA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO005  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO009 Evaluation of 60pC Beam Performance at cERL Injector for ERL Based EUV-FEL cavity, optics, electromagnetic-fields, space-charge 699
 
  • T. Hotei
    Sokendai, Ibaraki, Japan
  • R. Kato, T. Miyajima
    KEK, Ibaraki, Japan
  
  In order to compensate for the emittance which is increased by space charge in the low energy region, it is important to transport the beam as designed. Until now, we did not consider couplers in injector superdonducting cavities in optics design. But in this study, to improve optics matching and emittance compensation conditions for space charge dominated beam in cERL at KEK, we introduced a new 3D cavity model. We first investigated the influence of the couplers on electromagnetic field distribution. As a result, it was found that an asymmetric focusing force is generated by the influence of the couplers. It also became clear that the influence of the coupler kick on the optics significantly devastated the emittance compensation condition from the calculating including space charge. Furthermore, it was found that by optimizing the optics in consideration of the coupler kick, it is possible to improve the beam control accuracy and reduce the emittance in beam commissioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO009  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO032 CSNS Linac Beam Commissioning Tools and Experience MMI, linac, DTL, software 750
 
  • Y. Li, Z.P. Li, S. Wang
    IHEP, Beijing, People’s Republic of China
  • J. Peng
    CSNS, Guangdong Province, People’s Republic of China
  
  The China Spallation Neutron Source (CSNS) successfully accelerated the H− beam to 80 MeV in January 2018, marking a key progress in the beam commissioning. One of the keys to success is the development and use of software tools. XAL, a Java-based software infrastructure originally developed by SNS was applied for CSNS beam commissioning. We have developed and transplanted many applications based on XAL. Some of the applications for the Linac are described ,and some experiences are shared.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO032  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO036 Error Study of CPHS DTL after Assembly DTL, rfq, alignment, linac 763
 
  • P.F. Ma, C.T. Du, X. Guan, Q.K. Guo, Y. Lei, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • B.C. Wang
    NINT, Shannxi, People’s Republic of China
  
  The Compact Pulsed Hadron Source (CPHS) at Tsinghua University is one multi-purpose pulsed neutron source. The injector of the CPHS is a linac, which mainly consists of a source, a low-energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The error study of the DTL for CPHS is presented in this paper. The error study can provide the field tolerances in the DTL cavity and the alignment tolerance between the RFQ and DTL.  
poster icon Poster THPO036 [2.645 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO036  
About • paper received ※ 06 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO039 The Status of CSNS Front End rfq, ion-source, MMI, operation 771
 
  • H. Li, X. Cao, W. Chen, T. Huang, S. Liu, K. Xue
    CSNS, Guangdong Province, People’s Republic of China
  • S. Fu, Y.J. Lv, H.F. Ouyang, Y.C. Xiao
    IHEP, Beijing, People’s Republic of China
  
  CSNS front end is currently under running, which consists of a H− penning ion source(IS), a low energy beam transport(LEBT), a radio frequency quadrupole (RFQ) and a medium energy beam transport(MEBT). CSNS ion source is a type of Penning surface plasma source, similar to ISIS ion source. Cesium is used to enhance the H− ion production efficiency. The ion source is running with duty factor of 1.25%(25Hz and 500us). Normally, 40mA H− beam from ion source with 50keV can be delivered into LEBT. Three solenoids and two direction magnets are employed to transport and match the beam from the ion source into the RFQ. The pre-chopper is installed at the end of LEBT. The chopper mainly works at 3.8-4.2 kV and 1 MHz rate, which is about the RF frequency of the ring at injection. The rise time is less than 10ns，which fulfills the requirement of ring injection. For the RFQ, it is a 324MHz 4-vane type with a output energy of 3.0MeV and the length of 3.62m. The input cavity power is about 400kW. During commissioning, 16mA H− beam can be obtained at the exit of RFQ, and the RFQ transmission rate is up to 94%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO039  
About • paper received ※ 03 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO047 SPIRAL2 Injector Commissioning rfq, linac, cavity, diagnostics 790
 
  • R. Ferdinand, M. Di Giacomo, H. Franberg, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle, F. Varenne
    GANIL, Caen, France
  • D. Uriot
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  
  The SPIRAL2 injector is composed of two ion sources (p/d and heavy ions up to A/Q=3) followed by a 730 keV/u RFQ. Beam commissioning has started in 2014 in parallel with the superconducting linac and HEBT installations. The RFQ beam commissioning started soon after the first RF conditioning done in October 2015. This paper describes the RFQ beam measurements done on the diagnostic plate for the reference particles (H+, 4He2+ and recently 18O6+) and the difficulties encountered for the RFQ commissioning at the A/Q=3 field level.  
slides icon Slides THPO047 [7.846 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO047  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO048 Low Power Measurement of a 1300-MHz RFQ Cold Model rfq, linac, experiment, acceleration 794
 
  • Y. Kondo, T. Morishita, J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Otani
    KEK, Ibaraki, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Number 17K18784.
A muon linac development for a new muon g-2/EDM experiment is now going on at J-PARC. Muons from the muon beam line (H-line) of the J-PARC muon facility are once stopped in a silica aerojel target and room temperature muoniums are evaporated from the aerogel. They are dissociated with the lasers to be the ultra slow muons, then accelerated up to 212 MeV using a linear accelerator. The low energy part of this muon linac consists of a 324-MHz RFQ and an IH DTL. The frequency is increased to 1296 MHz at the following CCL section. We propose to replace the low energy section to a 1300-MHz RFQ to simplify the configuration of the muon linac. The 1300-MHz RFQ will be extremely small compared to conventional RFQs, therefore we made a cold model to proof the feasibility of this scheme. In this paper, the result of low-power measurement of the 1300-MHz RFQ cold model is described. 		 
slides icon Slides THPO048 [2.160 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO048  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO054 Recent Progress of a CW 4-rod RFQ for the SSC-LINAC rfq, linac, MMI, controls 814
 
  • Z.S. Li, Y. Cong, H. Du, Y. He, L. Jing, Q.Y. Kong, X.N. Li, J. Meng, G.D. Shen, K.D. Wang, Z.J. Wang, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, W.J. Xie, Z. Xu, J.C. Yang, Y.Q. Yang, X. Yin, Y.J. Yuan, Y. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  • Y.R. Lu
    PKU, Beijing, People’s Republic of China
  
  The SSC-LINAC is under design and construction as a linear injector for the Separated-Sector Cyclotron (SSC) of the Heavy Ion Research Facility at Lanzhou (HIRFL). The continuous-wave (CW) 4-rod radio-frequency quad-rupole (RFQ) of the SSC-LINAC has important progress in past years. In the autumn of 2016, the cavity has been operated with 35 kW on CW mode in automatic RF con-trolled mode during RF power commissioning, which is needed to accelerate 238U34+ beams. The beam transmis-sion efficiency, transverse emittance and energy spread has been obtained in beam commissioning. In this paper, the results of experiments will be presented and discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO054  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO057 Redesign of CERN Linac3 RFQ for Lead 29+ rfq, linac, cavity, simulation 818
 
  • S. Benedetti, G. Bellodi, J.-B. Lallement, A.M. Lombardi
    CERN, Geneva, Switzerland
  
  CERN Linac3 is at the start of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates 208Pb29+, though in recent years runs were performed with 40Ar11+ and 129Xe22+, in view of the increasing interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for 208Pb25+, the lower beam rigidity of the heavy ions currently in use and planned for the future permits a redesign of the RFQ optics aimed at increasing its transverse acceptance, and thus the transmitted beam current. A study of this has been performed, and the methodology adopted and the results are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO057  
About • paper received ※ 11 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, operation, electron 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 icon 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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THPO083 Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro cavity, diagnostics, vacuum, impedance 875
 
  • G. Kourkafas, T. Kamps, A. Neumann
    HZB, Berlin, Germany
  • B. Keune
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  
  The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these ambitious goals necessitates a thorough determination of the bunch parameters after the first acceleration stages, namely the photoinjector and the succeeding booster module. For the measurement of primarily the bunch duration and subsequently the longitudinal phase space and transverse slice emittance, a single-cell 1.3-GHz TM110-like mode vertically deflecting cavity was manufactured by RI Research Instruments GmbH, following the respective design developed for the Cornell ERL injector. This article summarizes the design parameters, manufacturing procedure and testing of this pulsed RF resonator, together with the expected temporal measurement resolution for the nominal beam energies at the initial acceleration stages of BERLinPro.  
poster icon Poster THPO083 [1.396 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO083  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO116 Space-Charge Dominated Photoemission in High Gradient Photocathode RF Guns cathode, space-charge, laser, gun 941
 
  • Y. Chen, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • H. Chen, Y. C. Du, W.-H. Huang, C.-X. Tang, Q.L. Tian, L.X. Yan
    TUB, Beijing, People’s Republic of China
  • H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Dohlus
    DESY, Hamburg, Germany
  • S. A. Schmid
    Institut Theorie Elektromagnetischer Felder, TU Darmstadt, Darmstadt, Germany
  
  The cathode emission physics plays a crucial role in the overall beam dynamics in the gun. Interplays between intricate emission mechanisms in the cathode vicinity strongly influence the cathode quantum efficiency (QE) and the intrinsic emittance. The presence of strong space-charge effects in high gradient RF guns further complicates the emission process. A proper modeling of photoemission and a careful treatment of the space-charge contribution is thus of great necessity to understanding the formation of the beam slice emittance. In this article, emission measurements are carried out using the L-band cesium-telluride photocathode RF gun at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) and the S-band copper photocathode RF gun at Tsinghua University. Following the Dowell model a simple so-called space-charge iteration approach is developed and used to determine the QE through temporal and spatial-dependent electromagnetic fields. An impact of the space-charge cooling on the thermal emittance is presented. Measurement data are shown and discussed in comparisons to preliminary simulation results.  
slides icon Slides THPO116 [6.249 MB]  
poster icon Poster THPO116 [3.157 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO116  
About • paper received ※ 11 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO118 Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ quadrupole, simulation, coupling, gun 945
 
  • Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • Q.T. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.  
poster icon Poster THPO118 [1.521 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118  
About • paper received ※ 08 September 2018       paper accepted ※ 20 September 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, electron, 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.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO124  
About • 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 electron, plasma, experiment, simulation 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 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO132  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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FR1A01 Results From the 6D Diagnostics Test Bench at SNS simulation, experiment, quadrupole, diagnostics 966
 
  • B.L. Cathey
    ORNL RAD, Oak Ridge, Tennessee, USA
  • A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This work has been partially supported by NSF Accelerator Science grant 1535312.
This paper presents the method and results for measuring the full six-dimensional phase space of a low energy, high intensity hadron beam. This was done by combining four-dimensional emittance measurement techniques along with dispersion measurement and a beam shape monitor to provide the energy and arrival time components. The measurements were performed on the new Beam Test Facility (BTF) at the Spallation Neutron Source (SNS), a 2.5 MeV functional duplicate of the SNS accelerator front end. The results include a correlation the had not previously been observed. 		 
slides icon Slides FR1A01 [7.083 MB]  
poster icon Poster FR1A01 [1.742 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A01  
About • 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, electron, 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 icon Slides FR1A02 [6.054 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A02  
About • paper received ※ 11 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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FR1A03 Frontiers of Beam Diagnostics in Plasma Accelerators plasma, diagnostics, radiation, laser 977
 
  • A. Cianchi
    Università di Roma II Tor Vergata, Roma, Italy
  • D. Alesini, M.P. Anania, M. Bellaveglia, F.G. Bisesto, M. Castellano, E. Chiadroni, G. Costa, M. Ferrario, F. Filippi, A. Giribono, A. Marocchino, A. Mostacci, R. Pompili, V. Shpakov, C. Vaccarezza, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  
  Advanced diagnostics tools are crucial in the development of plasma-based accelerators. Accurate measurements of the beam quality at the exit of the plasma channel are mandatory for the optimization of the plasma accelerator. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to the peculiarity of the emerging beams.  
slides icon Slides FR1A03 [3.494 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A03  
About • paper received ※ 06 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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