Measurement of response on d-T neutrons of two-stage system for neutron emission profile measurement using a neutron beam at FNS

FNS中性子ビームを用いた中性子分布計測のための2段計測システムのd-T中性子応答特性計測

篠原 孝司; 石井 啓一*; 落合 謙太郎; 馬場 護*; 笹尾 眞實子*; 北島 純男*

Shinohara, Koji; Ishii, Keiichi*; Ochiai, Kentaro; Baba, Mamoru*; Sasao, Mamiko*; Kitajima, Sumio*

A neutron flux array is one of the important plasma diagnostics to obtain the information on fast ion population. The d-T neutrons produced by deuteron-triton reaction bring us the information on 1 MeV tritons in deuterium plasmas in present-day tokamaks. However, the number of d-T neutrons is small, so that higher detection efficiency is required for a neutron detector. Here, we propose a multi-stage neutron detection system, in which several sets of a scintillator and photo-multiplier tube (PMT) are placed in a line-of-sight. In order to evaluate the performance of the multi-stage detection system, we have carried out experiments on a two-stage detection system using a d-T neutron beam at FNS (Fusion Neutronics Source) of JAEA (Japan Atomic Energy Agency). The results have shown the concept of the multi-stage detection system works as expected. In the best setup, the test two-stage system reached about 1.8 times the efficiency of a single scintillator and photomultiplier tube system.