Application of a Continuous Channel Electron Multiplier for Measuring Gaseous Tritium at Low Pressures

Abstract

Some fundamental studies on the application of a continuous channel electron multiplier (channeltron) for monitoring gaseous tritium present in an evacuated vessel at low pressures below 10^-4 Torr were carried out. The results showed that at the tritium pressures lower than 10^-6 Torr the tritium counting rate measured by the channeltron increased linearly, in practice, with increasing tritium pressure, as was expected by assuming that the interactions between β-particle emitted from tritium and the vessel wall and gaseous molecules during the migration of β-particle to the channeltron can be ignored. However, in the range of pressures over 10^-5 Torr the measured tritium counting rate was found to be getting smaller than the expected with increase in tritium pressure. This is presumably due to the absorption and scattering of β-particles by gaseous tritium.