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Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*
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Hara, Kaoru*; Fujii, Nobuya*; Sato, Hirotaka*; Narita, Yuki*; Kamiyama, Takashi*; Katabuchi, Tatsuya*; Iwamoto, Nobuyuki; Nakamura, Shoji; Toh, Yosuke
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Fukaya, Yuki
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Honda, Mitsunori; Goto, Takuya*; Sakanaka, Yoshihide*; Okamoto, Yoshihiro; Suzuki, Shinichi; Yaita, Tsuyoshi
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Oi, Motoki; Hosokawa, Hidemitsu*; Nishikawa, Masaaki*; Fukuda, Shimpei; Teshigawara, Makoto; Meigo, Shinichiro; Takada, Hiroshi
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At J-PARC, a neutron production target is installed in the helium vessel, and 3-GeV proton beams are delivered from a 3-GeV synchrotron to the target through a beamline with high vacuum environment. A proton beam window (PBW) is installed to isolate the helium vessel from the proton beamline. Since the PBW is degraded by radiation damage, it is scheduled to be replaced every 2 or 3 years under the 1-MW operation. In the summer outage in 2017, the PBW #2 was replaced to #3. A shielding cask was used for transferring the activated PBW, while hands-on works were done to remove the cooling water pipes at the top of the shielding plug of PBW. Since the cooling water contains 510 Bq/cc of tritium, it was drained from the pipes and the pipes were dried before removing PBW. The hands-on work was carried out in a green-house with a local exhaust device to prevent scattering of radioactive materials. In this presentation, we report the replacement work of the PBW including safety measures.
Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*
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Kajimoto, Ryoichi; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Murai, Naoki
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Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Shibata, Kaoru; Kawakita, Yukinobu; Matsuura, Masato*; Endo, Hitoshi*; Seto, Hideki*; Ito, Shinichi*; Nakajima, Kenji; et al.
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Oikawa, Kenichi; Harjo, S.; Kiyanagi, Yoshiaki*; Kawasaki, Takuro; Morito, Shigekazu*; Ito, Masakazu*; Oba, Takuya*; Pham, A.*; Shinohara, Takenao; Kai, Tetsuya
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Shibata, Kaoru; Kawakita, Yukinobu; Nakagawa, Hiroshi; Yamada, Takeshi*; Tominaga, Taiki*; Matsuura, Masato*
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A time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), DNA was built and started operation in 2012 at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). It offers a high-energy resolution of about 1.6 micro eV and very wide energy scan range: -400 E/[micro eV] +600 with signal-to-noise ration of 100,000. Those factors gave big advantage to enlarge application fields to dynamical behaviors of atoms and spins in bio-molecules, soft-materials and strongly-correlated electron system in nanosecond timescale or in micro-eV energy region.
Harada, Masahide; Kawakami, Kazuhiro*; Aizawa, Kazuya; Soyama, Kazuhiko; Ishikado, Motoyuki*; Hiramatsu, Hideyuki*; Hashimoto, Norimichi*; Hosoya, Tomonori*; Ichimura, Katsuhiro*
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Sakai, Kenji; Oi, Motoki; Takada, Hiroshi; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*
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Sakai, Kenji; Oku, Takayuki; Harada, Masahide; Kai, Tetsuya; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kira, Hiroshi*; Shimizu, Hirohiko*; Hirota, Katsuya*; Okudaira, Takuya*; et al.
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Inamura, Yasuhiro; Ito, Takayoshi*; Yasu, Yoshiji*; Oshita, Hidetoshi*
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Utsusemi is the software to analyze and visualize data measured by the neutron scattering experiments at MLF in J-PARC. Users in MLF require to see the analyzed data while measuring to decide next experimental schedules. We, therefore, had started to develop the software to obtain the information, analysis and visualization of measured data in real time since last year. We report the current status for these developments.
Okamoto, Yoshihiro; Nagai, Takayuki; Kobayashi, Hidekazu; Shiwaku, Hideaki; Ayame, Yasuo
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The synchrotron radiation based XAFS technique, in which atomic element selectivity and adaptation to a diluted component can be achieved, has been used widely for research work on the nuclear waste vitrification technology. We have used the XAFS technique for many kinds of simulated glass samples. The use of XAFS technique is very effective since many kinds of elements are contained in the nuclear waste glass. In addition, imaging XAFS technique was introduced, since some elements such as platinum group metals in the glass are not distributed uniformly. In this presentation, we summarize some results obtained from the XAFS and imaging XAFS analyses we have performed for advancement of the vitrification technology.
Haga, Katsuhiro; Wakui, Takashi; Wakai, Eiichi; Naoe, Takashi; Kogawa, Hiroyuki; Takada, Hiroshi
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The maximum beam power for user operation of the present neutron target vessel is limited to 700 kW due to the allowable thermal stress. However, to allow the rated 1-MW operation, the next neutron target vessel changed the target structure and the water channel arrangement to reduce the thermal stress for achieving 1MW beam power. In the new target vessel design, the mercury vessel and water shroud were separated in the front half part of the target vessel where the heat generation density is high, and the water channel arrangement was optimized to reduce the thermal stress caused by the difference of thermal expansion between those two vessels. The fabrication design was changed to reduce the total parts number to be the minimum, and the number of welding lines was drastically reduced by fabricating each part from the block of stainless steel with wire electrode discharge machining. The welding deformation and the residual stress were also reduced by applying electron beam welding to part of the welds. Furthermore, the radiation tests and ultra-sonic tests were applied in the fabrication processes to check the soundness of welds. As for the cavitation damage caused by the pressure wave, the damage depth of the specimen cut out from the used neutron target vessel which was operated at the beam power of 150 kW to 200 kW was measured, and damage data to improve the damage evaluation under the non-bubble condition was obtained.
Wakai, Eiichi; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Guan, W.; Hanano, Kohei*; Kinoshita, Hidetaka; Narui, Norio*; Haga, Katsuhiro; Teshigawara, Makoto; et al.
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Kubota, Masato; Sakurai, Takeaki*; Miyadera, Tetsuhiko*; Nakao, Hironori*; Sugita, Takeshi*; Yoshida, Yuji*
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Nakatani, Takeshi
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The MLF advanced computational apparatus introduced in this year is available to manage the enormous data produced by the new measurement method developed in MLF, which are the Multi-Ei measurement, stroboscopic measurement, etc. The apparatus is consist of the high performance network switches in MLF and the J-PARC Research Building (JRB), the wide band network between MLF and JRB and the 200TB2 large capacity storages in JRB. The backbone network between the buildings is double 40 Gbps optical fibers according to the increase of MLF beam power. The storages are paralleled to be able to read and write the data from each instrument without delay. Additionally, because the network switches and the connection among them are redundant, it is robust that the network will be automatically switched on the incident situations which are equipment failure or communication path fault.
Hiroi, Kosuke; Su, Y. H.; Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Segawa, Mariko; Hayashida, Hirotoshi*; Matsumoto, Yoshihiro*; Parker, J. D.*; Kiyanagi, Yoshiaki*
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no abstracts in English