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Mattan, K.*; Ono, Toshio*; Kawamura, Seiko; Nakajima, Kenji; Nambu, Yusuke*; Sato, Taku*
Physical Review B, 105(13), p.134403_1 - 134403_8, 2022/04
Times Cited Count:3 Percentile:48.5(Materials Science, Multidisciplinary)Spin dynamics of the spin-1/2 kagome-lattice antiferromagnet CsCuSnF was studied using high-resolution, time-of-flight inelastic neutron scattering. The flat mode, a characteristic of the frustrated kagome antiferromagnet, and the low-energy dispersive mode, which is dominated by magnons, can be well described by the linear spin-wave theory. However, the theory fails to describe three weakly dispersive modes between 9 and 14 meV. These modes could be attributed to two-spinon bound states, which decay into free spinons away from the zone center and at a high temperature, giving rise to continuum scattering.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Kobayashi, Yukinori*; Sakanaka, Shogo*; Sato, Kotaro*; Kasuga, Toshio*; Kawata, Hiroshi*; Hajima, Ryoichi; Nakamura, Norio*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.66 - 69, 2009/08
Future synchrotron light source based on the Energy Recovery Linac (ERL) is expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation with a potential of the oscillating type for X-ray free electron laser. We are constructing the R&D machine which is called the compact ERL including the developments of an ultra-low emittance electron gun and superconducting cavities for both the injector and the main linacs under the collaboration between KEK, JAEA, ISSP, and other institutes. In this paper, we report recent progress of the construction for the compact ERL with a repair of a KEK east counter hall.
Tomita, Kenji; Tsuchiya, Kunihiko; Onuma, Yuichi; Inoue, Shuichi; Watanabe, Hiroyuki; Saito, Takashi; Kikuchi, Taiji; Hayashi, Kimio; Kitajima, Toshio
JAEA-Technology 2008-036, 61 Pages, 2008/06
The second in-situ irradiation experiment using a mock-up (ORIENT-II, JMTR capsule Number: 99M-54J) with a tritium breeder (LiTiO) pebble bed in the Japan Materials Testing Reactor (JMTR) was finished on Aug. 1, 2006. Consideration on the detaching procedure of the irradiated mock-up contaminated with tritium with pebble bed and a detaching test of this mock-up was carried out. The tritium removal properties were examined in the irradiated mock-up, the sweep gas tube, the protective tube and the junction box, for the decreasing of the tritium release to the area of detaching test. Melting/enclosed tests of sealing plug were also carried out for the prevention of tritium leakage from sweep gas lines of pebble bed. Then, the detaching test of the pebble bed was carried out. This report describes the results of tritium removal tests, examination of the detaching procedure, and the detaching test, as well as knowledge obtained from these tests and works.
Iimura, Koichi; Hosokawa, Jinsaku; Kanno, Masaru; Kitajima, Toshio; Nakagawa, Tetsuya; Sakamoto, Taichi; Hori, Naohiko; Kawamura, Hiroshi
JAEA-Technology 2008-035, 47 Pages, 2008/06
At Oarai Research and Development Center, Japan Atomic Energy Agency (JAEA) advances the plan of refurbishing Japan Materials Testing Reactor (JMTR) to start the operation in fiscal 2011. As part of effective use for JMTR, JAEA is planning to product Mo, which is a parent nuclide of Tc. Tc is most commonly used as a radiopharmaceutical in the field of nuclear medicine. Currently the supplying of Mo is only depend on imports from foreign countries, so JAEA is aiming at domestic production of a part of Mo in cooperation with the industrial circles. In this article, JAEA described the process, the choice and fabric of the irradiation facilities for Mo production, the technical study of commercializing equipment after irradiation, and the cost study for Mo production.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Hayashi, Kimio; Nakagawa, Tetsuya; Onose, Shoji; Ishida, Takuya; Kodaka, Hideo; Katsuyama, Kozo; Kitajima, Toshio; Takahashi, Kozo; Tsuchiya, Kunihiko; Nakamichi, Masaru; et al.
JAEA-Technology 2008-010, 68 Pages, 2008/03
In-pile functional tests of breeding blankets for fusion reactors have been planned by Japan Atomic Energy Agency (JAEA), using a test blanket module (TBM) which will be loaded in ITER. The present report describes a conceptual investigation and a basic design of the dismantling process for irradiation capsules which were used in irradiation experiments by the Japan Materials Testing Reactor (JMTR) of JAEA. In the present design, the irradiation capsule is cut by a band saw; the released tritium is recovered safely by a purge-gas system, and is consolidated into a radioactive waste form. Furthermore, adoption of the inner-box enclosing the dismantling apparatus has brought a prospect to be able to utilize an existing hot cell (beta- cell) equipped with usual wall material permeable to tritium, without extensive refurbishing of the cell. Thus, the present study has indicated the feasibility of the present dismantling process for the irradiated JMTR capsules containing tritium.
Sakanaka, Shogo*; Kobayashi, Yukinori*; Sato, Kotaro*; Kasuga, Toshio*; Kawata, Hiroshi*; Hajima, Ryoichi; Nakamura, Norio*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.225 - 227, 2008/00
Collaborative research efforts towards future ERL-based light sources are carried out. We present the R&D status of an electron gun and superconducting cavities, updated design study on the test facility (Compact ERL).
Takahashi, Yoshihiro*; Oki, Takahiro*; Nagasawa, Takaharu*; Nakajima, Yasuhito*; Kawanabe, Ryu*; Onishi, Kazunori*; Hirao, Toshio; Onoda, Shinobu; Mishima, Kenta; Kawano, Katsuyasu*; et al.
Nuclear Instruments and Methods in Physics Research B, 260(1), p.309 - 313, 2007/07
Times Cited Count:4 Percentile:35.71(Instruments & Instrumentation)no abstracts in English
Terada, Atsuhiko; Hino, Ryutaro; Hirayama, Toshio; Nakajima, Norihiro; Sugiyama, Hitoshi*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 6 Pages, 2007/04
The Japan Atomic Energy Agency has been conducting study on thermochemical IS process for water splitting hydrogen production. Based on the test results and know-how obtained through the bench-scale test, a pilot test plant, which has a hydrogen production performance of 30 Nm/h, is being designed conceptually as the next step of the IS process development. In design of the IS pilot plant, it is important to make chemical reactors compact with high performance from the viewpoint of plant cost reduction. A new hydraulic analytical code has been developed for optimizing mixing performance of multi-phase flow involving chemical reactions especially in the Bunsen reactor. Preliminary analytical results obtained with above mentioned code, especially flow patterns induced by swirling flow agreed well with that measured by water experiments, which showed vortex breakdown pattern in a simplified Bunsen reactor.
Nakajima, Norihiro; Araya, Fumimasa; Hirayama, Toshio
Genshiryoku eye, 52(10), p.22 - 34, 2006/10
no abstracts in English
Suzuki, Yoshio; Aoyagi, Tetsuo; Tani, Masayuki; Nakajima, Norihiro; Hirayama, Toshio
Genshiryoku eye, 52(10), p.35 - 39, 2006/10
no abstracts in English
Makihara, Akiko*; Asai, Hiroaki*; Tsuchiya, Yoshihisa*; Amano, Yukio*; Midorikawa, Masahiko*; Shindo, Hiroyuki*; Kuboyama, Satoshi*; Onoda, Shinobu; Hirao, Toshio; Nakajima, Yasuhito*; et al.
Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.95 - 98, 2006/10
no abstracts in English
Ikeshima, Yoshiaki; Ishida, Takuya*; Tsuchiya, Kunihiko; Tomita, Kenji; Ebisawa, Hiroyuki; Magome, Hirokatsu; Nakamichi, Masaru*; Kitajima, Toshio; Kawamura, Hiroshi
JAERI-Tech 2005-005, 37 Pages, 2005/02
no abstracts in English
Hazama, Osamu; Nakajima, Norihiro; Hirayama, Toshio; Post, P.*; Wolf, K.*
IWACOM, P. 161, 2004/11
The numerical methods and computational hardware of today allow for studies on multi-disciplinary simulations. We have been developing an "integrated numerical simulation system" to solve coupled simulation problems under meta-computing environments. The system aims to construct a competent coupler for carrying out multi-disciplinary simulations by allowing concurrent execution of arbitrary simulation codes on different computers in parallel. The effectiveness of this system infrastructure is illustrated through its applications to fluid-structure interactive problems.
Nakajima, Norihiro; Kimura, Hideo; Higuchi, Kenji; Aoyagi, Tetsuo; Suzuki, Yoshio; Hirayama, Toshio; Yagawa, Genki
Dai-23-Kai Nihon Shimyureshon Gakkai Taikai Happyo Rombunshu, p.117 - 120, 2004/06
The pablic acceptance of nuclear power plants operations requests information of status for the safety and ease. Previous technology in computational scinece is generarlly carried out the analysis as an uniform structure, although the plants are assembled by thousand of parts. The proposed approach is to develope assembled structural analysis and fluid/heat analyis in assembled structures under the natural and actual environmnet such as daily operation, small quakeing which does not induce shut down procedure, and so on.
Ono, Toshio*; Tanaka, Hidekazu*; Kolomiyets, O.*; Mitamura, Hiroyuki*; Goto, Tsuneaki*; Nakajima, Kenji; Osawa, Akira; Koike, Yoshihiro; Kakurai, Kazuhisa; Klenke, J.*; et al.
Journal of Physics; Condensed Matter, 16(11), p.S773 - S778, 2004/03
Times Cited Count:64 Percentile:89.38(Physics, Condensed Matter)no abstracts in English
Ito, Haruhiko; Homma, Kenzo; Itabashi, Yukio; Tabata, Toshio; Akashi, Kazutomo; Inaba, Yukio; Kumahara, Hajime; Takahashi, Kunihiro; Kitajima, Toshio; Yokouchi, Iichiro
JAERI-Review 2003-024, 76 Pages, 2003/10
no abstracts in English
Kanno, Masaru; Kitajima, Toshio; Homma, Kenzo
KAERI/GP-195/2002, p.71 - 75, 2002/00
Recent irradiation studies aiming at clarifying the detailed mechanisms of irradiation damages to the reactor materials require to maintain the specimens at constant temperature regardless of the reactor power level,in order to avoid artificial effects of temperature transient due to reactor power change. In order to deal with this problem, JMTR has adopted feed-foward control to the gas pressure based on the reactor power signal, and developed new temperature control technique in combination with feedback control of heater power.
Kurihara, Ryoichi; Ajima, Toshio*; Ueda, Shuzo; Seki, Yasushi
Journal of Nuclear Science and Technology, 38(7), p.571 - 576, 2001/07
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)no abstracts in English