Operation of a capillary plate under high-pressure 3He for neutron detection

We evaluated the neutron-detection performance of a capillary plate under high-pressure 3He in terms of the gas gain and the distribution of pulse heights, with the aim of using the device as a neutron detector and a gas preamplification device. The capillary plate exhibited a gas gain of more than 1000 up to a gas pressure of 6 atm. with a 5% mixture of ethane, confirming an adequate gas gain as a neutron detector. It was also found that the pulse shape of the induced-signal pulses were correlated with the emission angle of the secondary particles, protons and tritons, thereby providing useful information for developing a system with position-sensitive readouts with a high spatial resolution and a low background.