Author: Tanaka, O. A.
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MOPGW038 Collimator’s Impact Into the Transverse Emittance Growth at KEK Compact ERL 174
 
  • O. A. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, Y. Tanimoto
    KEK, Ibaraki, Japan
 
  In high-intensity particle accelerators, unwanted trans-verse and longitudinal wakefields arise when the high-charge particle beam passes through the narrow chambers or locations with small transverse apertures, such as collimator jaws. Transverse wakefields impose a transverse kicks to the beam, changing its shape, and leading to the growth of the transverse emittance. Longitudinal wakes cause the beam energy losses, heating of the narrow chambers etc. In the present study we investigated the collimator’s impact to the beam. Thus, we evaluated the collimator’s wakefields through the CST simulations. We estimated the corresponding transverse kicks and longitudinal wakes. In the summary simulation results were cross-checked with correspondent analytical expressions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW038  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPGW036 1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance 1482
 
  • T. Obina, D.A. Arakawa, M. Egi, T. Furuya, K. Haga, K. Harada, T. Honda, Y. Honda, T. Honma, E. Kako, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, T. Konomi, H. Matsumura, T. Miura, T. Miyajima, S. Nagahashi, H. Nakai, N. Nakamura, K. Nakanishi, K.N. Nigorikawa, T. Nogami, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, M. Shimada, M. Tadano, T. Takahashi, R. Takai, O. A. Tanaka, Y. Tanimoto, T. Uchiyama, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • R. Hajima, R. Nagai, M. Sawamura
    QST, Tokai, Japan
  • N. Nishimori
    National Institutes for Quantum and Radiological Science and Technology (QST), Sayo-cho, Japan
 
  A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %.
* S. Sakanaka, et.al., Nucl. Instr. and Meth. A 877 (2017)197, https://doi.org/10.1016/j.nima.2017.08.051
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW036  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPMP012 New Industrial Application Beamline for the cERL in KEK 3475
 
  • Y. Morikawa, K. Haga, M. Hagiwara, K. Harada, N. Higashi, T. Honda, Y. Honda, M. Hosumi, Y. Kamiya, R. Kato, H. Kawata, Y. Kobayashi, H. Matsumura, C. Mitsuda, T. Miura, T. Miyajima, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, M. Tadano, R. Takai, H. Takaki, O. A. Tanaka, Y. Tanimoto, A. Toyoda, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
 
  The new beam line for the industrial applications is constructed at the cERL (compact Energy Recovery LINAC) in KEK. In these applications, only north straight sections of cERL consisting of injector and main LINAC will be used. The test for the radio isotope production and electron beam irradiation for the materials are firstly planned with very small beam current without energy recovery.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP012  
About • paper received ※ 11 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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