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Meigo, Shinichiro; Shigyo, Nobuhiro*; Iga, Kiminori*; Iwamoto, Yosuke*; Kitsuki, Hirohiko*; Ishibashi, Kenji*; Maehata, Keisuke*; Arima, Hidehiko*; Nakamoto, Tatsushi*; Numajiri, Masaharu*
AIP Conference Proceedings 769, p.1513 - 1516, 2005/05
For validation of calculation codes that are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found the NMTC/JAM generally shows in good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20 to 80 MeV, whereas the NMTC/JAM gives 50 % of the experimental data for the heavy nuclide target such as lead and tungsten target.
Maekawa, Fujio; Meigo, Shinichiro; Kasugai, Yoshimi; Takada, Hiroshi; Ino, Takashi*; Sato, Setsuo*; Jerde, E.*; Glasgow, D.*; Niita, Koji*; Nakashima, Hiroshi; et al.
Nuclear Science and Engineering, 150(1), p.99 - 108, 2005/05
Times Cited Count：6 Percentile：40.47(Nuclear Science & Technology)A neutronic benchmark experiment on a simulated spallation neutron target assembly with 1.94, 12 and 24 GeV proton beams conducted by using the AGS accelerator at BNL/US was analyzed to investigate validity of neutronics calculations on proton accelerator driven spallation neutron sources. Monte Carlo particle transport calculation codes NMTC/JAM, MCNPX and MCNP-4A with associated cross section data in JENDL and LA-150 were used for the analysis. As a result, although the overall energy range was encompassed from GeV to meV, i.e., more than 12 orders of magnitude, calculated fast and thermal neutron fluxes agreed approximately within 
40 % with the experiments. Accordingly, it was concluded that neutronics calculations with these codes and cross section data were adequate for estimating nuclear properties in spallation neutron sources.
Tamura, Masaya; Maekawa, Fujio; Harada, Masahide; Haga, Katsuhiro; Konno, Chikara
JAERI-Tech 2005-020, 58 Pages, 2005/03
JAERI-Tech-2005-020.pdf:18.82MB
no abstracts in English
Kai, Tetsuya; Harada, Masahide; Maekawa, Fujio; Teshigawara, Makoto; Konno, Chikara; Ikeda, Yujiro
Journal of Nuclear Science and Technology, 41(Suppl.4), p.172 - 175, 2004/03
In J-PARC neutron source, intense protons (3 GeV,1 MW) pass through a proton-beam window and bombard a Hg target in a target-moderator-reflector-assembly (TMRA). The SS316 target chamber is the most highly activated. Decouplers (Ag-In-Cd (AIC) alloy) are also highly activated. Some neutron extraction holes of Be and AL-coated iron reflector are lined with AIC alloy. A SS316 shield is located outer the TMRA. All these components are cooled by H
O or DO. We estimated the induced-radioactivity of the TMRA components and the cooling water using NMTC/JAM, MCNP4 and DCHAIN-SP. As results, the remote maintenance and massive shields were indispensable. For example, a 30 cm thick Fe cask for the reflector assembly was necessary to attenuate the radiation less than 1 mSv/h. The cask required a 130-ton crane. The AL-coated Fe of the reflector was adopted instead of SS316 resulting in eliminating the high activity of Ni in SS316 and reduction of the cask weight. Based on these results, shielding wall designs and maintenance scenarios of the highly activated components are developed.
Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Niita, Koji*; Takada, Hiroshi; Meigo, Shinichiro; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 3, p.1041 - 1049, 2003/07
A radioactivity calculation code system DCHAIN-SP was validated in view of the following points: (1) Activation cross section data library for the energy region below 20 MeV. (2) NMTC/JAM code for calculation of the nuclide yield induced by the high energy particles above 20 MeV. (3) DCHAIN-SP code system which treats overall nuclide yield by the high energy particles. 42 of activation cross sections and 22 tritium production cross sections were revised so that the DCHAIN-SP calculation could improve its accuracy within 30% for typical materials irradiated by 14-MeV neutrons. The NMTC/JAM code was improved to implement the GEM model for better estimation of light fragment production. Accuracy of the nuclide yield for proton induced reactions in 10 MeV - 10 GeV still remains in the level of a factor of 2 to 3. The DCHAIN-SP code system was employed for the analysis of time evolution of the radioactivity produced in the samples on a thick mercury target bombarded with 2.83 and 24 GeV protons. It is found that the code system agrees with the measured data by a factor of 2 to 3.
Meigo, Shinichiro; Harada, Masahide; Takada, Hiroshi
Proceedings of ICANS-XVI, Volume 3, p.1059 - 1067, 2003/07
In the neutronics design for the J-PARC facilities, transport codes of NMTC/JAM, MCNPX and MARS are used. In order to confirm the predict ability for these codes, it is important to compare with the experiment result. For the validation of the source term of neutron, the calculations are compared with the experimental spectrum of neutrons produced from thick target. Although slightly disagreement exists, NMTC/JAM, MCNPX and MARS are in good agreement with the experiment within by a factor of 2.
Meigo, Shinichiro; Harada, Masahide; Teraoku, Takuji*; Maekawa, Fujio
Proceedings of ICANS-XVI, Volume 3, p.1175 - 1180, 2003/07
It is important to monitor the proton beam for the high intensity pulse spallation target. Especially for the beam halo, which may irradiate the bulk surrounding the target, it is important to be observed to prevent causing heat spot in the shielding bulk. At JSNS, a proton beam monitors are located at front of the target. These monitors are assembled with the proton beam window. Since this scheme increases the radiation on the monitor due to the beam loss at the windows, it may arise heat deposition on the monitor. Therefore, heat deposition is calculated with NMTC/JAM. It is found that the heat deposition for normal operation is less than 0.1 W/cc.
Niita, Koji*; Takada, Hiroshi; Meigo, Shinichiro; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research B, 184(3), p.406 - 420, 2001/11
Times Cited Count：79 Percentile：97.72(Instruments & Instrumentation)no abstracts in English
Niita, Koji*; Meigo, Shinichiro; Takada, Hiroshi; Ikeda, Yujiro
JAERI-Data/Code 2001-007, 128 Pages, 2001/03
JAERI-Data-Code-2001-007.pdf:5.07MB
no abstracts in English
Kasugai, Yoshimi; Takada, Hiroshi; Nakashima, Hiroshi; Sakata, Hideaki*; Maekawa, Fujio; Ikeda, Yujiro; Kawai, Masayoshi*; Ino, Takashi*; Jerde, E.*; Glasgow, D.*; et al.
JAERI-Conf 2001-002, p.955 - 963, 2001/03
no abstracts in English
Maekawa, Fujio; Niita, Koji*; Meigo, Shinichiro; Kasugai, Yoshimi; Ikeda, Yujiro; Takada, Hiroshi; Ino, Takashi*; Sato, Setsuo*; ASTE Collaboration Team
JAERI-Conf 2001-002, p.983 - 991, 2001/03
no abstracts in English
Maekawa, Fujio; Teshigawara, Makoto; Konno, Chikara; Ikeda, Yujiro; Watanabe, Noboru
JAERI-Conf 2001-002, p.907 - 916, 2001/03
no abstracts in English
Takada, Hiroshi; Meigo, Shinichiro; Niita, Koji*
Advanced Monte Carlo for Radiation Physics, Particle Transport Simulation and Applications, p.949 - 954, 2001/00
no abstracts in English
