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Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio
JAEA-Data/Code 2015-033, 28 Pages, 2016/03
JAEA-Data-Code-2015-033.pdf:1.78MB
The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within 
30%.
Hanada, Masaya; Kashiwagi, Mieko; Inoue, Takashi; Watanabe, Kazuhiro; Imai, Tsuyoshi
Review of Scientific Instruments, 75(5), p.1813 - 1815, 2004/05
Times Cited Count：30 Percentile：76.86(Instruments & Instrumentation)A proof-of-principle test on plasma neutralizer, that is capable of enhancing a system efficiency of neutral beam injector for future fusion reactors, has been carried out. A 2 m long and 0.6 m diamater neutralizer with multicusp magnet line was used, improving the confinement of primary electrons flowed from both ends of the neutralizer by a pair of magnets. This improvement produced relatively high density Ar plasma of 10
- 10
cm
at low operating pressure of 0.002 Pa - 0.03 Pa. In the neutralization experiment, 200 keV H
ion beams were neturalized with the plasms and gas. Compared with the gas neutralization, the maximaum neutralization efficiency by the plasma was 6% higher than that by the gas. Further, an optimum Ar gas line density for maximizing the neutralization efficiency was 30% lower than that by the gas. These results are in good agreements with results analyzed from the cross-section data for neturalization. Thus, it was experimentally verified that the neutralization effiency can be enhanced at relatively low line density by using the plasma.
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
Kudo, Hiroshi*; ; ; Takeshita, Hidefumi; Aoki, Yasushi; Yamamoto, Shunya; Naramoto, Hiroshi
Nuclear Instruments and Methods in Physics Research B, 90, p.533 - 536, 1994/00
no abstracts in English
