Beam dynamics, extreme beams, sources and beam related technologies
Beam Dynamics, beam simulations, beam transport
Paper Title Page
TU1P01 Extreme High Brightness Electron Beam Generation in a Space Charge Regime 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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TU1P03
 Observation of Resonant Coherent Diffraction Radiation from a Multi-bunch Electron Beam Passing Through an Optical Cavity  
 
  • Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, T. Uchiyama, N. Yamamoto
    KEK, Ibaraki, Japan
  • T. Hotei
    Sokendai, Ibaraki, Japan
  
  Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991.
Energy Recovery Linac can realize a linac-type beam at a high current. An ERL test accelerator, cERL, has been constructed in KEK. Utilizing these features of the ERL beam, low emittance, short bunch, and high repetition rate, we have been developing a unique terahertz radiation source of resonant coherent diffraction radiation. An optical resonant cavity consists of two concave mirrors with a beam hole at the center was installed in the return-loop of cERL. When the multi-bunch electron beam passes through the cavity, it radiates coherent diffraction radiation in the cavity. If the round-trip time of the cavity precisely matches the beam repetition, the radiation of the bunches are stacked coherently and stimulates the energy conversion process from the beam to the radiation. Measuring the terahertz radiation power while scanning the cavity length, we observed a sharp resonance peak showing the realization of the stimulated emission. The cavity was carefully designed to tune the carrier-envelope-offset to be zero. It allows to excite wide-band longitudinal modes simultaneously, and realize a mode-locked terahertz pulse. 		 
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TUPO078 Extension of Busch’s Theorem to Particle Beams 516
TUOP09   use link to see paper's listing under its alternate paper code  
 
  • 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 519
TUOP10   use link to see paper's listing under its alternate paper code  
 
  • 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 522
SPWR033   use link to see paper's listing under its alternate paper code  
 
  • 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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TUPO084 Beam Dynamics Simulations for the New Superconducting CW Heavy Ion LINAC at GSI 525
SPWR034   use link to see paper's listing under its alternate paper code  
 
  • M. Schwarz, M. Basten, M. Busch, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  
  Funding: Work supported by BMBF contr. No. 05P15RFRBA, EU Framework Programme H2020 662186 (MYRTE) and HIC for FAIR
For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI/HIM and IAP is currently in progress. It aims for developing a supercon-ducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The LINAC design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with unchanged minimum energy spread. Testing of the first CH-cavity in 2016 demonstrated a promising maximum accelerating gradient of Ea = 9.6 MV/m; the worldwide first beam test with this sc multi-gap CH-cavity in 2017 was a milestone in the R&D work of GSI/HIM and IAP. In the light of experience gained in this research so far, the beam dynamics layout for the entire LINAC has recently been updated and optimized. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO084  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO085 Modelling of Beam Parameters of RF Linac for GBS-ELI-NP 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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TUPO088 Measurement of Diagnostics Response by RF Parameters for Hard X-ray Line in PAL-XFEL* 531
 
  • H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: *This work is supported by MSIP, Korea.
PAL-XFEL is a hard x-ray (HX) and soft x-ray (SX) FEL machine to generate 2.5 - 15 keV FEL in the HX line and 0.28 - 1.2 keV FEL in the SX line. The HX line consists of an e-gun, a laser heater, S-band accelerators, an X-band linearizer, three bunch compressors (BC), and a dog-leg line. PAL-XFEL maintains the stable operation and FEL delivery with more than 98% availability due to machine stabilities including RF modules. In order to investigate the stable operation, we measure the diagnostics response for bunch charge monitors, energy beam position monitors, bunch length monitors, and a FEL intensity with a photon beam position monitor by RF parameters - RF amplitude and phase for an e-gun, accelerators, and a linearizer. In this paper, we present mainly corresponding RF parameters for e-beam and FEL jitters by this measurement and matrix analysis. 		 
poster icon Poster TUPO088 [0.281 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO088  
About • paper received ※ 11 September 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 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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TUPO091 Beam Break Up Instability Analysis for Cavities, Linacs and Energy Recovery Linacs 537
 
  • V. Volkov, V.M. Petrov
    BINP SB RAS, Novosibirsk, Russia
  
  This analyze argue that BBU instability both in separate cavities and in Linacs or ERLs is going due to the consequence of fundamental property of dipole modes. ’Head-tail’ bunch instability has also the same nature. New BBU instability testing methods are described and analytically proved in the article.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO091  
About • paper received ※ 14 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO092 Beam Dynamics and Collimation Following MAGIX at MESA* 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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TUPO093 Excitation of Millimeter Wavelength Cavity Structure 543
SPWR030   use link to see paper's listing under its alternate paper code  
 
  • 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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TUPO095 Beam Loading with the First Rebuncher of Spiral2, First Measurements 546
 
  • M. Lechartier, R. Ferdinand, J.F. Leyge
    GANIL, Caen, France
  
  In the SPI2 project the middle energy line (LME) is equiped with a radio frequency qupole and three Rebunchers. The subject of this article is to measure and characterise the effect of the beam loading on the first Rebuncher cavity.  
poster icon Poster TUPO095 [1.146 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO095  
About • paper received ※ 20 September 2018       paper accepted ※ 15 January 2019       issue date ※ 18 January 2019  
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TUPO097 Design of C-band Electron Linear Accelerator for a Complex of Radiation Therapy 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 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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TUPO101 Design of Practical HSC Type Injector for Cancer Therapy 557
 
  • C.C. Xing, T. He, C.X. Li, J. Li, L. Lu, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The Hybrid single cavity(HSC), which is designed for 20 mA beam acceleration, is a new HSC Type Injector for Cancer Therapy. Its designed particle, resonant frequency, injection and final energies are designed from beam-optics considerations of the entire system to be C6+, 100MHz, 20keV/u and 0.6MeV/u. In order to achieve these requirements, keeping the Maximum surface electric field to less than 1.9-times the Kilpatrick limit, the RFQ becomes about 1.2 m long and the DTL is about 2.5 m long. The total efficiency of transmission is more than 80%.  
poster icon Poster TUPO101 [0.345 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO101  
About • paper received ※ 12 September 2018       paper accepted ※ 20 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 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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TUPO109 Electron Cloud Estimates for the Jefferson Lab EIC 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-200 566
SPWR032   use link to see paper's listing under its alternate paper code  
 
  • 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 icon 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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TUPO113 Beam Dynamics Studies Through Dielectric THz Accelerating Structures 569
 
  • R. Apsimon, G. Burt, A.L. Healy, S.P. Jamison
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • R.B. Appleby, E.J.H. Smith
    UMAN, Manchester, United Kingdom
  • A. Latina
    CERN, Geneva, Switzerland
  
  As conventional RF accelerating schemes approach the physical limit of accelerating gradient, the accelerator community is increasingly looking at novel accelerating techniques to overcome these limitations. Moving from the RF to the THz frequency range, higher acceleration gradients of high energy beams can be achieved in compact structures. Beam dynamics studies are crucial as part of the design of novel accelerating structures to maximise the output beam current as well as the accelerating gradient. In this paper we present beam dynamics simulations through dielectric lined waveguide structures using novel techniques to simulate broadband signals for particle tracking studies in RF-Track. The beam parameters through the structure are optimised and we study the dynamics of general broadband accelerating structures.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO113  
About • paper received ※ 13 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO114 Beam Dynamics Studies for the CSNS DTL Due to a Quadrupole Fault 573
 
  • J. Peng, M.T. Li, Y.D. Liu, X.H. Lu, X.B. Luo
    CSNS, Guangdong Province, People’s Republic of China
  • Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan
    IHEP, Beijing, People’s Republic of China
  
  The China Spallation Neutron Source(CSNS) accelera-tor systems is designed to deliver a 1.6GeV, 100kW pro-ton beam to a solid metal target for neutron scattering research. It consists of a 50keV H− Ion Source, a 3MeV Radio Frequency Quadrupole (RFQ), an 80MeV Drift Tube Linac (DTL), and a 1.6GeV Rapid-cycling Synchro-tron (RCS). The DTL consists of four tanks. In 2017, three of four tanks have been commissioned successfully, and beam has been accelerated to 61MeV with nearly 100% transmission. However, in July 2017, one quadrupole contained in the drift tube was found fault, the beam transmission decreased to 80%. A new lattice has been designed and the 100% transmission has recovered. In January 2018, the last tank of the DTL has been commissioned and accelerated the H− beam to the design energy of 80MeV for the first time. The commissioning progress and the measurement results before and after lattice adjustment will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO114  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO115 Beam Parameters Measurement and Correction in CSNS Linac 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 579
SPWR031   use link to see paper's listing under its alternate paper code  
 
  • 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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TUPO119 A Diagnostics Box for the Linear Accelerator of Institute for Research in Fundamental Science (IPM) 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 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 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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TH1A05 Jitter Study for the APS Linac Photo-injector Beam 647
 
  • D. Hui, M. Borland, J.M. Byrd, Y. Sun
    ANL, Argonne, Illinois, USA
  
  Funding: *Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS Linac photo-injector can deliver high brightness electron beams to the Linac Extension Area (LEA) for beam experiments such as TESSA (Tapering Enhanced Stimulated Superradiant Amplification). Beam jitter in the device-under-test (DUT) area of the LEA can adversely affect the quality of data for such experiments. In this paper, a start-to-end simulation of jitter is studied. Sources of jitter include photo-cathode drive-laser arrival time, laser energy, and RF phases and voltages of the photo-cathode gun and accelerating cavities. It is found that at the DUT the relative mean energy jitter is the most significant concern, and that improvements in the Linac RF voltage stability can help to reduce it. RMS energy spread are more sensitive to the laser timing and charge jitter. The laser timing jitter itself can be compressed by the magnetic chicane by a factor of 5.6. 		 
slides icon Slides TH1A05 [4.377 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1A05  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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