Author: Obina, T.
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MOPO082 Commissioning Status of the Linac for the iBNCT Project 174
  • M. Sato, Z. Fang, M.K. Fukuda, Y. Fukui, K. Futatsukawa, Y. Honda, K. Ikegami, H. Kobayashi, C. Kubota, T. Kurihara, T. Miura, T. Miyajima, F. Naito, K. Nanmo, T. Obina, T. Shibata, T. Sugimura, A. Takagi, E. Takasaki
    KEK, Ibaraki, Japan
  • K. Hasegawa
    JAEA, Ibaraki-ken, Japan
  • H. Kumada, Y. Matsumoto, Su. Tanaka
    Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
  • N. Nagura, T. Ohba
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  • T. Onishi
    Tsukuba University, Ibaraki, Japan
  • T. Ouchi, H. Sakurayama
    ATOX, Ibaraki, Japan
  Boron neutron capture therapy (BNCT) is one of the particle-beam therapies which use secondary products from a neutron capture on boron medicaments implanted into cancer cells. This has been originally studied with neutrons from nuclear reactors, meanwhile, many activities have been recently projected with accelerator-based neutron generation. In the iBNCT (Ibaraki BNCT) project, the accelerator is consisted with a radio frequency quadrupole (RFQ) and an Alvarez type drift-tube linac (DTL). Protons extracted from an ion source are accelerated up to 3 MeV and 8 MeV, respectively, and bombarded onto a beryllium target to generate neutrons. The design of the linac is based on the J-PARC one, but the most significant difference is the higher duty factor to have a sufficient epithermal neutron flux for BNCT. We have started the commissioning from the end of 2016, and the beam current of 1.3 mA with a repetition of 50 Hz has been achieved with an acceptable stability. Further beam commissioning and reinforcement of the vacuum and cooling water system will be performed toward higher beam current. In this contribution, the current status and future prospects of the linac will be presented.  
DOI • reference for this paper ※  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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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.
slides icon Slides TU1P03 [1.740 MB]  
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