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Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kajimoto, Ryoichi; Takahashi, Nobuaki*; Nakamura, Mitsutaka; Soyama, Kazuhiko; Osakabe, Toyotaka
EPJ Web of Conferences, 83, p.03011_1 - 03011_5, 2015/01
Times Cited Count：3 Percentile：72.17(Physics, Multidisciplinary)We report the design of the beam-transport system (especially the vertical geometry) for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.
Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; Sakamoto, Yukio*; Nakashima, Hiroshi; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.337 - 340, 2014/04
The Neutrinos at the Main Injector (NuMI) at Fermilab produces intense neutrino beam to investigate the phenomena of the neutrino mixing and oscillation. The Hadron Absorber, consists of thick blocks of aluminum, iron and concrete, is placed at the end of decay volume as a dump for primary proton and secondary particles generated in NuMI. In order to estimate the shielding effect, the reaction rate measurements with activation detector were carried out on the back surface of the absorber. The induced activities in the detectors were measured by analyzing their 
-ray spectra using HPGe detectors. Two kind of peak was showed on two-dimensional distributions of obtained reaction rates at right angle to the beam direction. One was strong peaks at the both horizontal side. And, another smaller was at the top. It was concluded that these peaks were the results of particles streaming through the gaps in the Hadron Absorber shielding.
Matsumura, Hiroshi*; Kinoshita, Norikazu*; Iwase, Hiroshi*; Toyoda, Akihiro*; Kasugai, Yoshimi; Matsuda, Norihiro; Sakamoto, Yukio; Nakashima, Hiroshi; Yashima, Hiroshi*; Mokhov, N.*; et al.
Journal of the Korean Physical Society, 59(2), p.2059 - 2062, 2011/08
Times Cited Count：1 Percentile：11.35(Physics, Multidisciplinary)In an antiproton production (Pbar) target station of the Fermi National Accelerator Laboratory (FNAL), the secondary particles produced by bombarding a target with 120-GeV protons are shielded by a thick iron shield. In order to obtain experimental data on high-energy proton accelerator facilities, we indirectly measured 
100-MeV neutrons at the outside of the iron shield. The measurement was performed by using the Au activation method coupled with a low-background -ray counting system. As an indicator for the neutron flux, we determined the production rates of 8 spallation nuclides (
Au, 
Pt, 
Ir, 
Os, 
Hf, 
Lu, 
Lu, and 
Yb) in the Au activation detector. The measured production rates were compared with the theoretical production rates calculated using PHITS. We proved that the Au activation method can serve as a powerful tool for indirect measurements of 100-MeV neutrons that play a vital role in neutron transport.
Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Takahashi, Nobuaki; Aizawa, Kazuya; Suzuya, Kentaro; Shibata, Kaoru; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB028_1 - SB028_6, 2011/05
Times Cited Count：125 Percentile：95.7(Physics, Multidisciplinary)AMATERAS is a cold-neutron disk-chopper spectrometer in MLF, J-PARC. The construction of main part of the spectrometer has been completed in spring of 2009. Soon after that, we have started the commissioning work on AMATERAS. The performance of AMATERAS has been examined by test experiments in the course of commissioning. In parallel to these works, we have started the user program on AMATERAS from December 2009 and we are getting scientific results from our spectrometer. In this presentation, we will report the current status of AMATERAS including the results of performance tests and some of examples of scientific outputs.
Kajimoto, Ryoichi; Nakajima, Kenji; Nakamura, Mitsutaka; Osakabe, Toyotaka; Sato, Taku*; Arai, Masatoshi
Journal of Neutron Research, 16(3-4), p.81 - 86, 2008/09
Cold Neutron Double-Chopper Spectrometer (CNDCS) is under construction for the spallation neutron source at Materials and Life Science Facility (MLF), Japan Proton Accelerator Research Complex (J-PARC). It is dedicated for research of inelastic phenomena with low energy transfer utilizing an incident energy of 
meV. It has a 30 m moderator-sample distance (
) and a supermirror-coated neutron guide tube between the moderator and the sample. The guide tube is curved to eliminate unwanted fast neutron and ray emitted immediately after a proton hits the target. In the present paper, we present the performance of the curved guide of CNDCS obtained by Monte Carlo simulation using McStas. We will report energy dependence of gain in intensity and beam distributions for several kinds of supermirrors, in comparison to the case utilizing a 
chopper and a straight guide.
Nakajima, Kenji; Nakamura, Mitsutaka; Kajimoto, Ryoichi; Osakabe, Toyotaka; Kakurai, Kazuhisa; Matsuda, Masaaki; Metoki, Naoto; Wakimoto, Shuichi; Sato, Taku*; Ito, Shinichi*; et al.
Journal of Neutron Research, 15(1), p.13 - 21, 2007/03
no abstracts in English
Mori, Michiaki; Kando, Masaki; Daito, Izuru; Kotaki, Hideyuki; Hayashi, Yukio; Ogura, Koichi; Sagisaka, Akito; Esirkepov, T. Z.; Nakajima, Kazuhisa; Daido, Hiroyuki; et al.
International Journal of Modern Physics B, 21(3&4), p.407 - 414, 2007/02
Times Cited Count：0 Percentile：0.01(Physics, Applied)The quasi-monoenergetic electron beam produced by intense laser-plasma interaction was observed at plasma densities from 
to 
. The terawatt laser beam was focused by using an off-axis parabolic mirror with f=648 mm. We observed quasi-monoenergetic electron beams in the forward direction. The peak energy of quasi-monoenergetic component of the electron beam was increased from 9 MeV to 
20 MeV with a energy spread of 20
increasing the plasma density from to . However, the quasi-monoenergetic component of the electron beam disappeared at a plasma density of 
, and non-equilibrium (non Maxwellian) spectrum of the electron beam was observed. The table-top laser driven fs quasi-monoenergetic electron beam which is applicable to variety of fields has been demonstrated.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Osakabe, Toyotaka; Sato, Taku*; Nakajima, Kenji; Arai, Masatoshi
Physica B; Condensed Matter, 385-386(2), p.1236 - 1239, 2006/11
Times Cited Count：9 Percentile：41.55(Physics, Condensed Matter)Performance of a neutron guide has been studied for the Cold Neutron Double-Chopper Spectrometer (CNDCS) proposed for the spallation neutron source at J-PARC. This spectrometer is dedicated to inelastic neutron scattering studies in vast research fields in an energy range of 
80 meV. In order to detect weak inelastic signals, increasing neutron flux on sample with suppressing background at detector is very important. Installing a neutron guide is a well-known solution to these problems, because it can deliver much more neutrons to sample, and it can also cut off unwanted fast neutrons when installed in a curved layout. The performance of a neutron guide is much affected by its geometry. We have studied efficiency of the beam transport by a supermirror-coated guide designed for the CNDCS with conventional geometries such as straight, curved and tapered, as well as with advanced geometries such as ballistic, parabolic and elliptical. Energy dependence of gain in intensity, and beam distributions in space and angle obtained by Monte Carlo simulation will be discussed.
Nakata, Toshiya; Komazaki, Shinichi*; Nakajima, Motoki*; Kono, Yutaka*; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Koyama, Akira*
Nihon Kinzoku Gakkai-Shi, 70(8), p.642 - 645, 2006/08
Times Cited Count：4 Percentile：34.16(Metallurgy & Metallurgical Engineering)no abstracts in English
Mori, Michiaki; Kando, Masaki; Daito, Izuru; Kotaki, Hideyuki; Hayashi, Yukio; Yamazaki, Atsushi; Ogura, Koichi; Sagisaka, Akito; Koga, J. K.; Nakajima, Kazuhisa; et al.
Physics Letters A, 356(2), p.146 - 151, 2006/07
Times Cited Count：46 Percentile：83.76(Physics, Multidisciplinary)The regimes of quasi-mono-energetic electron beam generation were experimentally studied inthe sub-relativistic intensity laser plasma interaction. The observed electron acceleration regime is unfolded with two-dimensional-particle-in-cell simulations of laser-wakefield generation in the self-modulation regime.
Mori, Michiaki; Kando, Masaki; Daito, Izuru; Kotaki, Hideyuki; Hayashi, Yukio; Ogura, Koichi; Sagisaka, Akito; Nakajima, Kazuhisa; Daido, Hiroyuki; Bulanov, S. V.; et al.
Proceedings of the International Workshop on Quark Nuclear Physics 2006, p.201 - 206, 2006/00
no abstracts in English
Kawano, Toshihiko*; Matsunobu, Hiroyuki*; Murata, Toru*; Zukeran, Atsushi*; Nakajima, Yutaka*; Kawai, Masayoshi*; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Osawa, Takaaki*; et al.
JAERI-Research 2003-026, 53 Pages, 2003/12
JAERI-Research-2003-026.pdf:2.48MB
New evaluations of neutron nuclear data for Uranium, Plutonium, and Thorium isotopes which are essential for applications to nuclear technology were carried out for the Japanese Evaluated Nuclear Data Library, JENDL-3.3. The objectives of the current release of JENDL were to fix several problems which have been reported for the previous version, to improve the accuracy of the data, and to evaluate covariances for the important nuclides. Quantities in JENDL-3.2 were extensively re-evaluated or replaced by more reliable values. The heavy nuclide data in JENDL-3.3 were validated with several benchmark tests, and it was reported that the current release gave a good prediction of criticalities.
Shibata, Keiichi; Kawano, Toshihiko*; Nakagawa, Tsuneo; Iwamoto, Osamu; Katakura, Junichi; Fukahori, Tokio; Chiba, Satoshi; Hasegawa, Akira; Murata, Toru*; Matsunobu, Hiroyuki*; et al.
Journal of Nuclear Science and Technology, 39(11), p.1125 - 1136, 2002/11
Times Cited Count：669 Percentile：96.97(Nuclear Science & Technology)Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for 
U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL-3.2.
Kawai, Masayoshi*; Nakagawa, Tsuneo; Watanabe, Takashi*; Nakajima, Yutaka*; Zukeran, Atsushi*; Matsunobu, Hiroyuki*; Sugi, Teruo*; Chiba, Satoshi
Journal of Nuclear Science and Technology, 38(4), p.261 - 269, 2001/04
no abstracts in English
Kawano, Toshihiko*; Matsunobu, Hiroyuki*; Murata, Toru*; Zukeran, Atsushi*; Nakajima, Yutaka*; Kawai, Masayoshi*; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Osawa, Takaaki*; et al.
Journal of Nuclear Science and Technology, 37(4), p.327 - 334, 2000/04
no abstracts in English
U,U,
U,
Pu,
Pu,and 
PuKawano, Toshihiko*; Matsunobu, Hiroyuki*; Murata, Toru*; Zukeran, Atsushi*; Nakajima, Yutaka*; Kawai, Masayoshi*; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Osawa, Takaaki*; et al.
JAERI-Research 2000-004, p.76 - 0, 2000/02
JAERI-Research-2000-004.pdf:2.39MB
no abstracts in English
*; Nakagawa, Tsuneo; *
JAERI-Data/Code 99-025, 46 Pages, 1999/04
JAERI-Data-Code-99-025.pdf:2.04MB
no abstracts in English
Tsuji, Hirokazu; ; Fujita, Mitsutane*; Kurihara, Yutaka*; Kano, Shigeki*; Tachi, Yoshiaki*; Shimura, Kazuki*; Nakajima, Ritsuko*; Iwata, Shuichi*
Journal of Nuclear Materials, 271-272, p.486 - 490, 1999/00
no abstracts in English
B, 
B, 
Mn, Pu and Pu neutron nuclear data in JENDL-3.2Shibata, Keiichi; *; Murata, Toru*
JAERI-Research 98-045, 48 Pages, 1998/08
JAERI-Research-98-045.pdf:1.64MB
no abstracts in English
Shimura, Kazuki*; Nakajima, Ritsuko*; Fujita, Mitsutane*; Kurihara, Yutaka*; Tsuji, Hirokazu; ; Tachi, Yoshiaki*; Kano Shigeki*; Iwata, Shuichi*
JAERI-Tech 97-047, 22 Pages, 1997/10
no abstracts in English
