Keyword: solenoid
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MOPO029 Physics design and dynamic simulation of a C-band photocathode electron gun for UEM electron, gun, emittance, cathode 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      issue date ※ 18 January 2019  
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MOPO129 Recent Results from the Study of Emittance Evolution at MICE emittance, detector, 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      issue date ※ 18 January 2019  
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TUPO065 Improvement of Cavity Performance by Nitrogen Doping at KEK cavity, ECR, SRF, accelerating-gradient 480
 
  • T. Okada, Y. Hori, E. Kako, T. Konomi, H. Sakai, K. Umemori, Y. Yamamoto
    Sokendai, Ibaraki, Japan
  • T. Dohmae, Y. Hori, E. Kako, T. Konomi, T. Saeki, T. Saeki, H. Sakai, K. Umemori, Y. Yamamoto
    KEK, Ibaraki, Japan
  • J. Kamiya
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Kurosawa, K. Takeishi
    JAEA, Ibaraki-ken, Japan
 
  Nitrogen doping experiments in single-cell and 3-cell niobium cavities were carried out at KEK. After annealing at 800 deg C for 3 hours, pure nitrogen gas with a pressure of 3 Pa for 20 minutes and 3 minutes were introduced for doping in a furnace in J-PARC, respectively. Removing surface in 5 um and 20 um by electropolishing were performed prior to the vertical tests, respectively. Increases of a quality factor at 2K and reduction of the BCS resistance with respect to an accelerating gradient were observed in both cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO065  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO066 Lower Critical Field Measurement of Thin Film Superconductor controls, experiment, SRF, embedded 484
 
  • H. Ito
    Sokendai, Ibaraki, Japan
  • C.Z. Antoine
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Four
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  • H. Hayano, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • R. Ito, T. Nagata
    ULVAC, Inc, Chiba, Japan
  • Y. Iwashita, R. Katayama, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
 
  Funding: The work is supported by Japan Society for the Promotion of Science Grant-in-Aid for Young Scientist (A) No.17H04839.
Superconducting thin film is the promising technology to increase the performance of SRF cavities. The lower critical field Hc1, which is one of the important physical parameters characterizing a superconducting material, will be enhanced by coating Nb with thin film superconductor such as NbN. To investigate the Hc1, we developed the Hc1 measurement system using the third harmonic response of applied AC magnetic field. The measurement system consists of helium cryostat with two of GM refrigerators, sample Cu stage, solenoid coil Cu mount, solenoid coil, temperature sensors, and liquid helium level meter. AC magnetic field is produced by a coil which is driven by function generator and power amplifier at around 1 kHz. In order to control the temperature of the sample, we installed heaters and thermal anchors which could be moved by the motor. By this temperature control the sample state can be easily transferred from Meissner state to mixed state. So that the measurement is repeated for various applied magnetic field, and the transition curve can be made. In this report, measurement result of the bulk Nb sample and NbN-SiO2 multilayer thin film sample will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO066  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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TUPO078 Extension of Busch’s Theorem to Particle Beams emittance, 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      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, emittance 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      issue date ※ 18 January 2019  
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TUPO090 Electron-beam Matching to Solenoid Magnetic Field in a Klystron klystron, gun, electron, cathode 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      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 electron, linac, acceleration, detector 566
 
  • A. Sledneva, V. Aleksandrov, V.V. Kobets
    JINR, Dubna, Moscow Region, Russia
 
  In the Joint Institute for Nuclear Research a Test Stand with an electron beam generated by the linear accelerator LINAC-200 with the energy up to 200 MeV is being constructed to investigate properties of accelerating and semiconducting structures for advanced detectors, a radiation resistance of detectors based on gallium arsenide semiconductor, to study a free electron laser and to do other applied for work. The technical characteristics of the LINAC-200 accelerator make it possible to create an advanced system of test beams for scientific and methodological studies of detectors on its basis. Four accelerating stations with maximum beam energy up to 200 MeV are put into operation. The work is being carried out for experiments with electron test beams with energy up to 800 MeV. This work presents the calculation results of the magnetic field of the focusing solenoidal system and electron beam dynamics in accelerating stations. In addition, the results on the formation of the electron beam with optimal parameters to be captured in further accelerating sections.  
poster 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      issue date ※ 18 January 2019  
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TUPO119 A Diagnostics Box for the Linear Accelerator of Institute for Research in Fundamental Science (IPM) linac, diagnostics, electron, dipole 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      issue date ※ 18 January 2019  
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