2.49 MeV陽子入射による$^7$Li(p, n)$^7$Be反応を用いたRANS-IIの中性子生成特性に関する予備実験

RANS-II, which aims to be the prototype of a compact neutron system for diagnostics of infrastructure, has recently completed in the construction and proton beam of 2.49 MeV successfully was accelerated and injected onto a Li target for neutron production. As the performance of the RANS-II neutron production target is one of most important keys from the neutronics point of view, we firstly set an experimental program to investigate the neutron characteristics with the RANS-II conditions based on the $^7$Li(n, p)$^7$Be reaction.
To measure neutrons below 1 MeV due to the maximum, we have examined two methods; a long counter with $^3$He which has a thick cylinder moderator for high energetic neutrons surrounded by low energy neutron absorber of B$_4$C, and the foil activation using the $^{115}$In(n, n’)$^{115m}$In reaction which has a low threshold energy of 336 keV. These reaction rates were calculated by the particle transport calculation code, PHITS, and compared with measurements.
It was found that there are considerably large discrepancies between experiments and calculations, systematically, and analyses are undertaken taking accounts of possible uncertainties in terms of numbers of proton, detector to source geometry, geometrical model relevant to the transport calculations, and so one. Discussions on nuclear data associated with the p-Li neutron production, such as detection cross sections are to be given.