Study of liquid methane purification monitor

Abstract

Measurements of high-energy neutrons above 50 MeV have been used neutron-hydrogen elastic scattering. Recently, the light signals of recoil protons from a liquid organic scintillator are most useful in this experiments. The higher neutron energy, the more enormous detector is necessary. It is difficult to gather uniform light in such liquid organic scintillator, and high-energy neutrons energy resolution becomes worse. Liquid methane has potential of detection of high-energy neutrons with high efficiency. A methane molecule contains one carbon nucleus and four hydrogen nuclei. Liquid methane works as a proton radiator because protons are emitted from the reaction by incident neutrons. Moreover methane has the nature of a noble gas, and can be used as a liquid ionization chamber. In order to construct a large volume liquid methane chamber and to get exact energy information, oxygen molecules, which capture drift electrons must be removed from methane. A liquid methane chamber was constructed with purification system and it was attempted to measure purity by using anode pulse signals of Am-241 alpha source.