日本原子力研究所Fuaion Neutronics Source(FNS)におけるD-T中性子スカイシャイン実験

概要

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The D-T neutron skyshine experiments have been carried out at the Fusion Xeutronics Source(FNS)of JAERT with the neutron yield of - 1.7 × 10^11 n/s. The concrete thick ness of the roof and the wall of a FNS target room are 1.15 and 2 in, respectively. The FNS skyshine port with a size of 0.9 × 0.9 m^2 was open during the experimental period. The radiation dose rale outside the target room was measured as far as about 550 m away from the D-T target point with a spherical rem-counter. The highest neutron dose was about 0.5μSv hr at a distance of 30 m from the D-T target point and the dose rate was attenuated to 0.002μSv hr a distance of 550 m. The measured neutron dose distribution was analyzed with Monte Carlo code MCNP-4B and a simple line source model. The MCNP calculation overestimates the neutron dose in the dislance range larger than 250 m. The neutron spectra were evaluated with a He detector with different thickness of polyethylene neutron moderators. Secondary gamma-rays were measured with high purify Ge detectors and Nal scintillation delectors.
社団法人プラズマ・核融合学会の論文
2003-03-25