A test of track imaging by cold neutron using optical capillary gas proportional counter

We have preliminarily investigated the performance of the optical capillary gas proportional counter (CGPC) to obtain the absorption point of cold neutron at JRR-3 in JAERI. The CGPC with a gas mixture of 3He+8%CH4+2%TMA at 1.1 atm was operated at the gas gain of up to 10 000. A track image produced from a nuclear reaction between a cold neutron and 3He was a straight line. For the track image, the triton and the proton were identified. The identification indicates that the neutron absorption point can precisely determine from the track image.