Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Isogawa, Hiroki*; Naoi, Motomasa*; Yamasaki, Seiji*; Ho, H. Q.; Katayama, Kazunari*; Matsuura, Hideaki*; Fujimoto, Nozomu*; Ishitsuka, Etsuo
JAEA-Technology 2022-015, 18 Pages, 2022/07
JAEA-Technology-2022-015.pdf:1.37MB
As a summer holiday practical training 2021, the impact of 10 years long-term shutdown on critical control rod position of the HTTR and the delayed neutron fraction (
) of the VHTRC-1 core were investigated using Monte-Carlo MVP code. As a result, a long-term shutdown of 10 years caused the critical control rods of the HTTR to withdraw about 4.0
0.8 cm compared to 3.9 cm in the experiment. The change in critical control rods position of the HTTR is due to the change of some fission products such as 
Pu, Am, 
Pm, Sm, 
Gd. Regarding the calculation of the VHTRC-1 core, the value is underestimate of about 10% in comparison with the experiment value.
Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Tasaki, Seiji*; Hino, Masahiro*; Matsubayashi, Masahito
Nuclear Instruments and Methods in Physics Research A, 634(1, Suppl.), p.S90 - S93, 2011/04
Times Cited Count：2 Percentile：19.86(Instruments & Instrumentation)In a neutron spin interferometer (NSI), incident neutrons are in states of up- and down-spin eigenstates and a phase difference between the eigenstates is observed after transmission through a magnetic sample. Since the phase difference is proportional to an integral of magnetic field along a trajectory of neutrons, NSI imaging provides projection images of a distribution of magnetic field in the sample. We tried to visualize magnetic field in permalloy film with and without stress as a demonstration of the NSI imaging. An experiment was carried out at C3-1-2-2, MINE2 port at the neutron guide hall of JRR-3M with wavelength of 0.88nm and wavelength resolution of 0.3% in FWHM. Permalloy film with thickness of 0.1 mm was used as a sample and was stressed by bending with angles of 45 and 180 
. As a result, images of decrease of a saturated magnetization and an increase of leak magnetic field with increasing the bending angle were obtained.
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Takeda, Masayasu; Maruyama, Ryuji*; Tasaki, Seiji*
Physica B; Condensed Matter, 356(1-4), p.174 - 177, 2005/02
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)Drabkin energy filter could be used as a fast chopper for pulsed neutrons by varying the resonant wavelength 
fast in such a way that resonant wavelength matches neutron wavelength at a small time region. The faster are varied, the smaller time window we could obtain. Neutron pulses could be sharpened much more effectively for a small wavelength band than in the wide-band pulse-shaping mode in which is varied in synchronization with the time-of-flight from the moderator. In our preliminary test of a chopper-mode with a prototype Drabkin energy filter, time-window of 0.21 ms was obtained while it was 1.08 ms with the filter driven stationary. Narrower time-window could have been obtained if we had more beam-time and it could be also narrowed with higher-resolution Drabkin filters.
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Takeda, Masayasu; Torikai, Naoya*; Tasaki, Seiji*; Matsuoka, Hideki*
Physica B; Condensed Matter, 356(1-4), p.229 - 233, 2005/02
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)The application of neutron reflectometry to study dynamic phenomena at surface and interfaces have been restricted so far. It was mainly due to the low intensity of neutron sources, but now high-intensity spallation neutron sources are under construction in Japan (J-PARC) and U.S. (SNS). We have a plan to install a spin-echo option on the J-PARC neutron reflectometer with horizontal sample geometry for studies on dynamics of surfaces and interfaces. This option is based on the resonance spin-echo method and aimed at dynamics upto hundreds of nanoseconds. In this contribution, the plan and status of development are introduced together with the principle and characteristics of this option.
Oku, Takayuki*; Sakai, Kenji*; Adachi, Tomohiro*; Ikeda, Kazuaki*; Shimizu, Hirohiko*; Maruyama, Ryuji*; Hino, Masahiro*; Tasaki, Seiji*; Kiyanagi, Yoshiaki*; Kamiyama, Takashi*; et al.
Physica B; Condensed Matter, 335(1-4), p.226 - 229, 2003/07
Times Cited Count：7 Percentile：39.38(Physics, Condensed Matter)no abstracts in English
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Tamura, Itaru; Tasaki, Seiji*
Proceedings of ICANS-XVI, Volume 1, p.407 - 415, 2003/06
Drabkin energy filters extract neutrons of required wavelength using spatial neutron spin resonance. If they are applied to pulsed neutrons, they could sharpen pulse width and cut tail neutrons without reducing band-width or peak-intensity. Shaping of J-PARC coupled-moderator pulse by a Drabkin energy filter was simulated. In the simulation, discrete field gradient to Bx is introduced and total field B is varied in accordance with the dominant wavelength at each moment at the filter position. The results suggest that about 90 % or more of tail neutrons from coupled moderator are cut and a fliter with fields of 200 periods could reduce pulse width up to that of decoupled moderator. Effects of fluctuations of width of each half period were studied and it was found that fluctuation within 1 % are tolerable for a flipper with field of 100 or 200 periods.
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Tasaki, Seiji*
JAERI-Research 2003-009, 29 Pages, 2003/03
JAERI-Research-2003-009.pdf:1.3MB
no abstracts in English
Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Takenaka, Nobuyuki*; Kageyama, Masashi*; Tasaki, Seiji*; Hino, Masahiro*; Kawabata, Yuji*; et al.
no journal, ,
no abstracts in English
Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Iikura, Hiroshi; Yasuda, Ryo; Sakai, Takuro; Matsubayashi, Masahito; Takenaka, Nobuyuki*; et al.
no journal, ,
no abstracts in English
Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Iikura, Hiroshi; Yasuda, Ryo; Sakai, Takuro; Matsubayashi, Masahito; Takenaka, Nobuyuki*; et al.
no journal, ,
no abstracts in English
Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Iikura, Hiroshi; Yasuda, Ryo; Sakai, Takuro; Matsubayashi, Masahito; Takenaka, Nobuyuki*; et al.
no journal, ,
no abstracts in English
