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observation of radiation-induced defects in ZrN under electron irradiation in HVEMRahman, M. M.*; Yamamoto, Tomokazu*; Matsumura, Sho*; Takaki, Seiya; Takano, Masahide; Costantini, J. M.*; Yasuda, Kazuhiro*
Nuclear Instruments and Methods in Physics Research B, 549, p.165289_1 - 165289_8, 2024/04
Times Cited Count：6 Percentile：73.07(Instruments & Instrumentation)Nucleation-and-growth process of radiation-induced defects in zirconium nitride (ZrN) has been investigated 
under electron irradiation by using a high voltage transmission electron microscope (HVEM) under electron irradiation by using a high voltage transmission electron microscope (HVEM).
Kamiya, Junichiro; Takano, Kazuhiro*; Wada, Kaoru; Yanagibashi, Toru*
e-Journal of Surface Science and Nanotechnology (Internet), 21(3), p.144 - 153, 2023/06
no abstracts in English
Kobayashi, Fuminori; Kamiya, Junichiro; Moriya, Katsuhiro; Miyao, Tomoaki*; Kotoku, Hirofumi*; Takano, Kazuhiro*
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.726 - 730, 2023/01
The L3BT beamline at J-PARC LINAC has beam dumps connected via vacuum partition windows to separate the ultra-high vacuum beamline from the low vacuum beam dumps. Roots pumps are used to evacuate each beam dump. The roots pump controllers have been installed away from the pump in the accelerator tunnel to avoid radiation damages. The special controllers, which have no inverter circuit inside, have been used to reduce the electrical noise on the beam loss monitors nearby. However, in this case, several problems have occurred such as the instability of the pumping performance. To solve such problems, the roots pump controller with the inverter circuit must be used after reducing the electrical noise. In this report, some countermeasures to reduce the electrical noise from the inverters were investigated. The noise reduction circuit was successfully optimized to the level where the beam loss monitors work unaffected.
Kamiya, Junichiro; Takano, Kazuhiro*; Yuza, Hiromu*; Wada, Kaoru
e-Journal of Surface Science and Nanotechnology (Internet), 20(2), p.107 - 118, 2022/05
no abstracts in English
Takano, Kazuhiro; Kotoku, Hirofumi*; Kobayashi, Fuminori*; Miyao, Tomoaki*; Moriya, Katsuhiro; Kamiya, Junichiro
JAEA-Technology 2021-017, 35 Pages, 2021/11
JAEA-Technology-2021-017.pdf:5.32MB
In J-PARC LINAC, the vacuum system of L3BT, which is a beam transport line connecting LINAC and 3GeV synchrotron, uses a turbo molecular pump and roots pump for rough exhaust and an ion pump for main exhaust. In addition, beam dumps are connected to the end of the L3BT at 0 degree, 30 degree, 90 degree, and 100 degree positions via vacuum partition windows. The roots pumps are used as the exhaust system for each beam dump. The roots pump controllers have been installed away from the pump in the accelerator tunnel to avoid radiation damages. Besides, the special controllers, which have no inverter circuit inside, have been used to reduce the electrical noise on the beam loss monitors nearby. However, using the special controller without inverters, several problems have occurred such as the instability or wide variability of the pumping speed. To solve such problems, the roots pump controller with the inverter circuit must be used after reducing the electrical noise. In this report, some countermeasures to reduce the electrical noise from the inverters were investigated. The noise reduction circuit was successfully optimized to the level where the beam loss monitors works unaffected.
Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.
JAEA-Technology 2021-001, 144 Pages, 2021/08
JAEA-Technology-2021-001.pdf:12.98MB
Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.
Kamiya, Junichiro; Kotoku, Hirofumi*; Kurosawa, Shunta*; Takano, Kazuhiro; Yanagibashi, Toru*; Yamamoto, Kazami; Wada, Kaoru
Physical Review Accelerators and Beams (Internet), 24(8), p.083201_1 - 083201_23, 2021/08
Times Cited Count：1 Percentile：10.56(Physics, Nuclear)Through the operation of the vacuum system in J-PARC, it becomes evident that the high-power beam has more powerful effects on the vacuum system than expected. Those effects are the malfunction of vacuum equipment and the large pressure rise. The former is the failure of the turbomolecular pump (TMP) controller. The TMP itself is also damaged by a bearing crush due to a touch-down. We have developed a TMP controller that can connect with long cables of more than 200 m lengths to install the controller in a control room where there is no radiation influence. The TMP with high-strength bearing has been also developed. The latter is an extreme pressure rise with increasing the beam power. It is indicated that the pressure rise mechanism is a result of ion-stimulated gas desorption. It is finally confirmed that the dynamic pressure during the high-power beam is effectually suppressed by additionally installing the NEG pumps.
Kamiya, Junichiro; Takano, Kazuhiro; Yuza, Hiromu*; Wada, Kaoru
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.3471 - 3474, 2021/08
The NEG coating, which has been developed in CERN, is a revolutionary technique that can make a beam pipe act as a vacuum pump by coating the getter materials with the ability to adsorb/absorb gas molecules on the beam pipe surface. The NEG materials are alloys of titanium, zirconium, and vanadium. Titanium is one of the getter materials. In high-power beam accelerators, titanium has been used as the beam pipe chamber material due to its low radioactivation characteristics. The ordinal titanium surface has no getter function because it is covered with titanium-oxide film. The new technique, which removes the titanium-oxide surface by the sputtering and makes the titanium vacuum chamber itself the vacuum pump like NEG coated chamber, has been developed. After sputtering the inner surface of the titanium chamber, we obtained clear evidence that shows the chamber acts as a vacuum pump. We have also tried to make a titanium chamber with a getter function only by baking. Dependence of the getter characteristics on the baking temperature will also be reported.
Rodriguez, G.*; Varaine, F.*; Costes, L.*; Venard, C.*; Serre, F.*; Chanteclair, F.*; Chenaud, M.-S.*; Dechelette, F.*; Hourcade, E.*; Plancq, D.*; et al.
EPJ Nuclear Sciences & Technologies (Internet), 7, p.15_1 - 15_8, 2021/00
France (CEA and FRAMATOME) and Japan (JAEA, MHI and MFBR) have carried out studies to establish a common technical view regarding sodium-cooled fast reactor concept. Japan and France performed a common work to examine ways to develop a feasible common design concept, which could be built both in France and/or in Japan. This paper is providing a review of this joint synthesis on Sodium Fast Reactor design concept.
Kusaka, Katsuhiro; Ohara, Takashi; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Kurihara, Kazuo; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; Ebata, Kazuhiro*; et al.
Physica B; Condensed Matter, 385-386(Part 2), p.1062 - 1065, 2006/11
Times Cited Count：12 Percentile：47.78(Physics, Condensed Matter)The TOF neutron biological diffractometer in J-PARC proposed by Ibaraki prefectural government is designed to cover the sample crystals which have their cell edges up to 135
, and to realize the efficiency which is more than 50 times larger than the present high performance diffractometers, BIX-3 and BIX-4 in JRR-3 reactor in JAERI. To achieve this performance, the diffractometer will be installed on a coupled moderator which has more intense peak and integrated intensity but wider pulse shape than a decoupled moderator. It is expected that some neighbor Bragg spots will overlap partially each other along the time-axis. It is necessary to de-convolute the overlapped spots in order to obtain a data set which has a quality good enough to identify hydrogen atoms in biological macromolecules. The original simulation programs of TOF diffraction data with designed parameters of the diffractometer were developed to obtain information of spot-overlapping and then to find the best procedure to de-convolute the overlapped spots. The strategy of de-convoluting overlapped Bragg spots will be reported based on the results of the simulations.
Shibata, Keiichi; Fukahori, Tokio; Takano, Hideki; ; Watanabe, Yukinobu*; Kobayashi, Katsuhei*; ; Oyamatsu, Kazuhiro*
Nihon Genshiryoku Gakkai-Shi, 39(10), p.863 - 865, 1997/00
no abstracts in English
Tanaka, Ichiro*; Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro*; Hosoya, Takaaki; Tomoyori, Katsuaki*; Niimura, Nobuo*; Ozeki, Tomoji*; Aizawa, Kazuya; Arai, Masatoshi; et al.
no journal, ,
IBARAKI Biological Crystal Diffractometer is a new single-crystal neutron diffractometer for biological and chemical crystallography, and is now being constructed at J-PARC by Ibaraki Prefectural Government in Japan. This diffractometer is designed for the protein crystals with the cell dimension up to 135 . The measurement efficiency is more than 50 times larger than the present neutron diffractometer, BIX-3/BIX-4 in JRR-3 reactor at JAEA. To achieve this performance, we have selected a coupled moderator, and worked out the optimisation of the neutron guide tube. For the detector, a new wavelength-shifting-fiber type scintillation area detector system with high spatial (0.5-1.0 mm) and time (1ms-) resolution are in development.
Miura, Kenta*; Umenyi, A. V.*; Hanaizumi, Osamu*; Sato, Takahiro; Ishii, Yasuyuki; Okubo, Takeru; Yamazaki, Akiyoshi; Koka, Masashi; Yokoyama, Akihito; Kada, Wataru; et al.
no journal, ,
no abstracts in English
Chiba, Kazuhiro*; Takano, Nao*; Yamamoto, Mitsuru*; Teranishi, Mika*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Hidema, Jun*
no journal, ,
no abstracts in English
Miura, Kenta*; Kikuchi, Shusuke*; Kiryu, Hiromu*; Inada, Kazuki*; Ozawa, Yusuke*; Hanaizumi, Osamu*; Yamamoto, Shunya; Sugimoto, Masaki; Yoshikawa, Masahito; Kawaguchi, Kazuhiro; et al.
no journal, ,
no abstracts in English
Kamiya, Junichiro; Wada, Kaoru; Takano, Kazuhiro
no journal, ,
The molecules, which diffuse from inside the material bulk, are thought to be the major outgassing source after the desorption of surface gas molecules becomes sufficiently small. The method for reducing the gas released from the bulk is a high-temperature heat treatment under a high vacuum, called vacuum firing. The conditions for vacuum firing are 900
C for 2 hours for stainless steel at CERN, 850C for 10 hours for titanium at J-PARC, and so on. These conditions are comprehensively determined in consideration of the amount of reduction in hydrogen concentration in the bulk, the diffusion distance, the mechanical strength, and the effect of sensitization in the case of stainless steel. We report that the build-up test revealed that there was a significant difference in the emission gas characteristics of the vacuum chamber with and without vacuum firing.
Kamiya, Junichiro; Takano, Kazuhiro; Wada, Kaoru; Yuza, Hiromu*
no journal, ,
Titanium is one of the getter materials. In high-power beam accelerators, titanium has been used as the beam pipe chamber material due to its low radioactivation characteristics. The ordinal titanium surface has no getter function because it is covered with titanium-oxide film. The new technique, which removes the titanium-oxide surface by the sputtering and makes the titanium vacuum chamber itself the vacuum pump like NEG coated chamber, has been developed. After sputtering the inner surface of the titanium chamber, we obtained clear evidence that shows the chamber acts as a vacuum pump. We have also tried to make a titanium chamber with a getter function only by baking. Dependence of the getter characteristics on the baking temperature has been obtained.
Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro; Hosoya, Takaaki; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.
no journal, ,
no abstracts in English
Ishigaki, Toru; Harjo, S.; Yonemura, Masao*; Kamiyama, Takashi*; Mori, Kazuhiro*; Mochiku, Takashi*; Aizawa, Kazuya; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*
no journal, ,
no abstracts in English
Ishigaki, Toru; Hoshikawa, Akinori; Yonemura, Masao*; Kamiyama, Takashi*; Harjo, S.; Aizawa, Kazuya; Sakuma, Takashi*; Tomota, Yo*; Morii, Yukio; Arai, Masatoshi; et al.
no journal, ,
Ibaraki prefecture, the local goverment of the area for J-PARC site, was decided to build a versatile neutron diffractometer (IBARAKI Materials Design Diffractometer) to promote a industrial application for neutron beam in J-PARC. This diffractometer is planned to be a high throughput diffractometer so that materials engineers and scientists can use it like the chemical analytical instruments in their materials development process. It covers in d range 0.18 
d () 5 with 
= 0.16% at high resolution bank, and covers 5 d () 800 with gradually changing resolution at three detector bank (90 degree, low angle and small angle). Typical measuring time to obtain a "Rietveld-quality" data is several minutes with the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutron but have not been familiar with neutron diffraction. The construction of this instrument was already begun and will be compleated in the beggining of 2008, as one of day-one instruments for J-PARC.
