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Maruta, Tomofumi; Ikegami, Masanori*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.420 - 423, 2013/08
no abstracts in English
Kawase, Masato; Yoshimoto, Masahiro; Yamazaki, Yoshio; Takeda, Osamu
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.734 - 737, 2013/08
no abstracts in English
Ikegami, Masanori*; Fang, Z.*; Futatsukawa, Kenta*; Miyao, Tomoaki*; Liu, Y.*; Maruta, Tomofumi; Sako, Hiroyuki; Miura, Akihiko; Tamura, Jun; Wei, G.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.64 - 67, 2013/08
ion source for the J-PARCYamazaki, Saishun; Ueno, Akira; Namekawa, Yuya*; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Koizumi, Isao; Oguri, Hidetomo
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.260 - 264, 2013/08
A cesium (Cs) seeded RF-driven H ion source using an internal-antenna developed at the SNS (Spallation Neutron Source) is under development for the J-PARC (Japan Proton Accelerator Research Complex). The axial magnetic field optimization by using an axial magnetic field compensation (AMFC) coil significantly enhances the H ion beam by typically 10%. An H ion beam with a flat top duty factor of 2.5% (1 ms 
25 Hz) of 77 mA, whose about 90% (corresponding to about 70 mA) of emittance of each direction is within 1.5 
mm
mrad, is successfully extracted. During a demonstration operation over 100-hours, an H ion beam over 66 mA was successfully produced with a relatively low RF power of about 40 kW by seeding Cs for 4-minutes a day.
Chishiro, Etsuji; Kawamura, Masato*; Hori, Toshihiko; Sato, Fumiaki; Shinozaki, Shinichi
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1224 - 1226, 2013/08
no abstracts in English
Fukui, Yuji*; Kawamura, Masato*; Kobayashi, Tetsuya*; Fang, Z.*; Futatsukawa, Kenta*; Sato, Fumiaki; Shinozaki, Shinichi; Suzuki, Hiroyuki; Chishiro, Etsuji; Hori, Toshihiko; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.762 - 764, 2013/08
no abstracts in English
Kawamura, Masato*; Chishiro, Etsuji; Hori, Toshihiko; Shinozaki, Shinichi; Sato, Fumiaki; Fukui, Yuji*; Futatsukawa, Kenta*; Yamazaki, Masayoshi*; Sagawa, Ryu*; Yukitake, Mitsuteru*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1243 - 1247, 2013/08
no abstracts in English
Ao, Hiroyuki; Asano, Hiroyuki; Tamura, Jun; Ouchi, Nobuo; Takata, Koji*; Naito, Fujio*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1124 - 1126, 2013/08
In the case of the RF window operated with the standing-wave cavity coupled to waveguides using coupling apertures, the reflection of the RF window affects the total coupling factor (voltage standing wave ratio, VSWR) consisted of the RF window and the cavity. Hence, the reflection (VSWR) of the RF window should be minimized not to change the cavity VSWR optimized separately, and to prevent standing waves between the RF window and the cavity. For minimizing the VSWR of the pillbox-type RF window, this report proposes that the dielectric constant of the ceramic is measured directly using the resonant frequency in the fabrication process of the RF window. In this work, three RF windows are fabricated additionally using the same type ceramic (NTK HA95), the small VSWR 
could be achieved using this procedure. This result also shows that the dielectric constant increases linearly with increasing the density.
Miyao, Tomoaki*; Igarashi, Zenei*; Miura, Akihiko; Mayama, Minoru*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.571 - 573, 2013/08
no abstracts in English
ray sourceNagai, Ryoji; Hajima, Ryoichi
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.980 - 982, 2013/08
Non-destructive measurement systems of nuclear material are under development in our group. The measurement systems are based on monochromatic -ray generated from laser Compton scattering (LCS) based on energy-recovery linac accelerator technologies. The accuracy improvement of the non-destructive measurement systems and the exploration of the precise excitation state in an atomic nucleus are attained by further developing a pure monochromatic LCS--ray source. The energy spread of a mode-locked short pulse laser restricts the monochromaticity of the LCS--ray source. Therefore, an ultra-narrow band width laser should be used for instead of the short pulse laser. We propose an asymmetric confocal Fabry-Perot optical resonator as a supercavity of the pure monochromatic LCS--ray source. We present R&D status and basic characteristic for such optical resonator.
Tamura, Jun; Ao, Hiroyuki; Asano, Hiroyuki; Ikegami, Masanori*; Maruta, Tomofumi; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Ouchi, Nobuo; Sawabe, Yuki*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.377 - 380, 2013/08
In the J-PARC linac, almost all the cavities and magnets have been precisely aligned because the accelerator tunnel has been deformed by the 2011 Tohoku Earthquake. In the beam transport line called MEBT2 and A0BT at the downstream of the drift tube linac, the beam duct has been roughly aligned after the precise alignment of the quadruple doublets. During the first beam operation after the earthquake, remarkable beam loss and residual radiation have been recognized at the MEBT2 and A0BT. As the result of the duct position measurement, the misalignement including over 10 mm shift from the beam axis was found. By conducting the beam duct realignment, the beam loss and the residual radiation were successfully decreased. In this paper, the procedure of the beam duct alignment and the beam loss due to the misalignment are described.
Ito, Takashi; Hirano, Koichiro; Nammo, Kesao*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1152 - 1156, 2013/08
After the recovery works from an earthquake, we started a high power conditioning of a DTL and an SDTL on November 2011 and restarted a beam acceleration on December 2011. The operation of the DTL and the SDTL was stable as with the operation before the earthquake without SDTL05B cavity. It was impossible to input an RF power into the SDTL05B in the about 300 kW to 400 kW range. Therefore the operating power was increased to 510 kW that is about 1.4 times those of before the earthquake. We have investigated the cause of this malfunction of SDTL05B, and a computer simulation showed that it is likely to be caused by a multipactor on the surface of the cavity wall. In this paper we present the result of the simulation, the various measurements and the countermeasure.
Nagai, Ryoji; Sawamura, Masaru; Nishimori, Nobuyuki; Hajima, Ryoichi
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.656 - 658, 2013/08
Technologies for the next generation light sources based on energy-recovery linac (ERL) are under development in our group. Photocathode related technology is a key technology for the ERL based light sources. Temporal shape control of the photocathode gun generated electron beam is indispensable to generate ultra-small emittance electron beam. A 1300 MHz deflecting cavity has been developed for a temporal shape measurement of an electron beam from a 250-kV DC photocathode electron gun. The cavity is a rectangle shaped TM120 mode with the unloaded quality factor 
= 17660. The deflecting angle is 
9.5 mrad for the electron bunch with 50 ps with 134.7 W input RF power.
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Koizumi, Isao; Takagi, Akira*; Namekawa, Yuya*; Yamazaki, Saishun; Ueno, Akira
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1081 - 1083, 2013/08
no abstracts in English
Ishiyama, Tatsuya; Ito, Yuichi; Kikuzawa, Nobuhiro; Suzuki, Takahiro; Oi, Motoki; Meigo, Shinichiro; Sakai, Kenji; Kato, Yuko
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.714 - 716, 2013/08
no abstracts in English
Yoshii, Akinobu; Kikuzawa, Nobuhiro
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.690 - 693, 2013/08
no abstracts in English
Matsuda, Makoto; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.362 - 366, 2013/08
no abstracts in English
Nishimori, Nobuyuki; Nagai, Ryoji; Matsuba, Shunya; Hajima, Ryoichi; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.255 - 259, 2013/08
no abstracts in English
Ishizaka, Tomohisa; Imai, Koji*; Yuri, Yosuke; Yuyama, Takahiro; Ishibori, Ikuo; Okumura, Susumu
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.594 - 596, 2013/08
no abstracts in English
Miura, Akihiko; Miyao, Tomoaki*; Ito, Takashi; Hirano, Koichiro; Nammo, Kesao*; Maruta, Tomofumi; Tamura, Jun; Ikegami, Masanori*; Naito, Fujio*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.653 - 655, 2013/08
The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.
