Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.
Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03
We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.
Otani, Masashi*; Futatsukawa, Kenta*; Miyao, Tomoaki*; Liu, Y.*; Hirano, Koichiro; Kondo, Yasuhiro; Miura, Akihiko; Oguri, Hidetomo
Journal of Physics; Conference Series, 1350, p.012078_1 - 012078_5, 2019/12
The Japan Proton Accelerator Research Complex (J-PARC) linac is operated with design peak current of 50 mA from 2018. For operation with such a high beam current, itis important to understand transverse and longitudinal beam properties especially in low-velocity region. A medium energy beam transport (MEBT1) line between the 3-MeV radio-frequency quadrupole linac (RFQ) and the 50-MeV drift-tube linac (DTL) is a 3-m-long transport line to match the beam to the DTL and produce a macro pulse configuration for a 3-GeV rapid-cycling synchrotron (RCS). In this paper, recent measurements and beam tuning results in MEBT1 will be presented.
Hayashi, Naoki; Hatakeyama, Shuichiro; Miura, Akihiko; Yoshimoto, Masahiro; Futatsukawa, Kenta*; Miyao, Tomoaki*
Proceedings of 7th International Beam Instrumentation Conference (IBIC 2018) (Internet), p.219 - 223, 2019/01
J-PARC is a multi-purpose facility. Accelerator stability is the one of important issues for users of this facility. To realize stable operation, we must collect data on interlocked events and analyze these data to determine the reasons for the occurrence of such events. In J-PARC Linac, data of interlocked events have been recorded using several some beam loss monitors and current monitors, and these data have been are analyzed and classified. In J-PARC RCS, new instrumentation is being introduced to obtain beam position. We discuss the present status and future plans related to this subject.
Otani, Masashi*; Futatsukawa, Kenta*; Hirano, Koichiro; Kondo, Yasuhiro; Miura, Akihiko; Oguri, Hidetomo; Liu, Y.*
Nuclear Instruments and Methods in Physics Research A, 908, p.313 - 317, 2018/11
It is extremely important to diagnose beams in accelerators to improve accelerator operation. In the low velocity section of a proton or heavy ion linac, the diagnostic method for longitudinal beam properties is less established compared to that for transverse properties. We have developed a new diagnostic method for the longitudinal bunch size by utilizing an RF deflector. We evaluated the uncertainty in bunch size measurement through simulation, and it was obtained as 0.5. In addition, we measured longitudinal beam emittance through bunch size measurements at several RF amplitudes of an upstream buncher. The measured emittance was 0.130.01 degMeV, which was consistent with the simulation result.
Moriya, Katsuhiro; Kawane, Yusuke*; Miura, Akihiko; Futatsukawa, Kenta*; Miyao, Tomoaki*
Journal of Physics; Conference Series, 1067, p.072009_1 - 072009_3, 2018/09
no abstracts in English
Hayashi, Naoki; Kikuzawa, Nobuhiro; Miura, Akihiko; Futatsukawa, Kenta*; Miyao, Tomoaki*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.540 - 544, 2017/12
The J-PARC linac operation is stable, however, the numbers of interlocked events due to single beam loss monitor (BLMP) is increasing. Recently, the counts is comparable to the number of RFQ trip, and a measure has been required for improvement of the operation efficiency. Thus, every event data has been analyzed and classified into three categories. It is found that there are characteristic signal or pattern of BLMP for every categories. Although the linac BLMP detector is standard, its setting parameters are differ from those of other two synchrotrons in the J-PARC. To optimize time resolution, the input impedance of its pre-amplifier is selected to be 50 and interlock is defined in raw signal height and width not integral signal of BLMP. Some new parameters has been tried to reduce unnecessary interlock.
Moriya, Katsuhiro; Okabe, Kota; Liu, Y.*; Miura, Akihiko; Futatsukawa, Kenta*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1081 - 1083, 2017/12
no abstracts in English
Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Kubo, Koji*; Sato, Kenichiro*; Wakai, Takashi; Shimomura, Kenta
Nihon Kikai Gakkai M&M 2017 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), p.591 - 595, 2017/10
no abstracts in English
Kondo, Yasuhiro; Asano, Hiroyuki*; Chishiro, Etsuji; Hirano, Koichiro; Ishiyama, Tatsuya; Ito, Takashi; Kawane, Yusuke; Kikuzawa, Nobuhiro; Meigo, Shinichiro; Miura, Akihiko; et al.
Proceedings of 28th International Linear Accelerator Conference (LINAC 2016) (Internet), p.298 - 300, 2017/05
We have constructed a linac for development of various accelerator components at J-PARC. The ion source is same as the J-PARC linac's, and the RFQ is a used one in the J-PARC linac. The beam energy is 3 MeV and nominal beam current is 30 mA. The accelerator has been already commissioned, and the first development program, laser-charge-exchange experiment for the transmutation experimental facility, has been started. In this paper, present status of this 3-MeV linac is presented.
Tamura, Jun; Miura, Akihiko; Morishita, Takatoshi; Okabe, Kota; Yoshimoto, Masahiro; Ao, Hiroyuki*; Futatsukawa, Kenta*; Maruta, Tomofumi*; Miyao, Tomoaki*; Nemoto, Yasuo*
Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2308 - 2310, 2017/05
In the Japan Proton Accelerator Research Complex (J-PARC), H particles generated by collisions of accelerated H beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H particles, the new analysis line for the H particles was installed in the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). In the analysis line, the accelerated H ions travel in chicane orbit by the four dipole magnets. In the beam commissioning, we directly detected the H particles by using a carbon plated installed to a wire scanner monitor and indirectly detected the H particles by using a scintillation detector. We also confirmed that the signals change with vacuum condition in the SDTL section.
Hayashi, Naoki; Kato, Yuko; Miura, Akihiko; Futatsukawa, Kenta*; Miyao, Tomoaki*
Proceedings of 5th International Beam Instrumentation Conference (IBIC 2016) (Internet), p.368 - 371, 2017/03
It is important to understand why the beam loss occurs during user operation. It is understandable that the beam loss results from RF cavities failure. However, it would be still useful to study the beam loss detailed mechanism and to know which beam loss monitor (BLM) experiences the highest loss or is most sensitive. This may lead a reduction in the number of interlocked events and a more stable accelerator operation. The J-PARC Linac BLM has a simple data recorder that comprises multiple oscilloscopes. Although its functionality is limited, it can record events when an interlock is triggered. Of particular interest here are the events associated with only the BLM Machine Protection System (MPS). These may reveal hidden problems with the accelerator.
Hirano, Koichiro; Asano, Hiroyuki; Ishiyama, Tatsuya; Ito, Takashi; Okoshi, Kiyonori; Oguri, Hidetomo; Kondo, Yasuhiro; Kawane, Yusuke; Kikuzawa, Nobuhiro; Sato, Yoshikatsu; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.310 - 313, 2016/11
We have used a beam scraper with the incident angle of 65deg to reduce the beam power deposition density in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC linac. The 65 scraper was irradiated by the H beam up to particle number of 1.47E22. We observed a lot of surface projections with several hundred micrometers high in the beam irradiation damage on the scraper by using the laser microscope. In order to study the limits of scrapers, we constructed a new 3 MeV linac at J-PARC. We will conduct the scraper irradiation test at the end of this year.
Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11
The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.
Futatsukawa, Kenta*; Kawane, Yusuke; Tamura, Jun; Nemoto, Yasuo; Hayashi, Naoki; Fukuoka, Shota*; Mayama, Minoru*; Miura, Akihiko; Miyao, Tomoaki*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1246 - 1250, 2015/09
no abstracts in English
Maruta, Tomofumi*; Liu, Y.*; Futatsukawa, Kenta*; Miyao, Tomoaki*; Miura, Akihiko; Ikegami, Masanori*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.432 - 436, 2015/09
no abstracts in English
Hirano, Koichiro; Kondo, Yasuhiro; Kawane, Yusuke; Shinozaki, Shinichi; Miura, Akihiko; Morishita, Takatoshi; Sawabe, Yuki; Sugimura, Takashi*; Naito, Fujio*; Fang, Z.*; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.944 - 947, 2015/09
Two RF-deflecting cavities as a chopper and a beam scraper have been used in the MEBT1 between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC Linac. We replaced with a newly fabricated RF chopper to decrease beam loss for the operation with 50 mA. We installed two new scrapers to absorb the higher power of the deflected beam by the RF chopper. This paper describes the RF chopper system and beam irradiation test results of the scraper.
Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08
Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the C reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet was measured to be (stat) (syst)keV from the direct transition. Excitation energies of the and states were measured to be , keV and , keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of hypernuclei.
Kada, Wataru*; Kambayashi, Yuya*; Miura, Kenta*; Saruya, Ryota*; Kubota, Atsushi*; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Hanaizumi, Osamu*
Key Engineering Materials, 643, p.15 - 19, 2015/05
Yamamoto, Masato*; Onizawa, Kunio; Yoshimoto, Kentaro*; Ogawa, Takuya*; Mabuchi, Yasuhiro*; Valo, M.*; Lambrecht, M.*; Viehrig, H.-W.*; Miura, Naoki*; Soneda, Naoki*
Small Specimen Test Techniques; 6th Volume (ASTM STP 1576), p.53 - 69, 2015/05
In order to ensure the robustness of the Master Curve technique, round-robin tests were performed using 0.16 inch-thick Mini-CT specimens by different investigators to see if consistent values can be obtained. All the specimens used were machined and pre-cracked by one fabricator from unique Japanese RPV material. Seven institutes participated in this exercise, and obtained valid values according to the ASTM E1921 standard. The scatter of values obtained was well within the uncertainty range defined in the standard, indicating the robustness of the Mini-CT specimen test technique. Throughout this activity, we could obtain 182 for a single material. We investigated the statistics of this large database, and found that there is no remarkable difference not only in the values but also in the fracture toughness distribution between the Mini-CT specimen and the standard size 1T-C(T) specimen results.
Kada, Wataru*; Miura, Kenta*; Kato, Hijiri*; Saruya, Ryota*; Kubota, Atsushi*; Sato, Takahiro; Koka, Masashi; Ishii, Yasuyuki; Kamiya, Tomihiro; Nishikawa, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research B, 348, p.218 - 222, 2015/04