制動X線計測法による高濃度トリチウムのIn-Situ測定(??) ベリリウム製窓の特性

概要

論文の詳細を見る
Improvements of the bremsstrahlung counting method proposed for in-situ measurements of high level tritium were performed from the viewpoint of increase in sensitivity. The major point of the improvements was made in regard to window material which acts as a generator and extractor of the bremsstrahlung X-rays. It was expected from computer simulation that a thin beryllium foil would be the most favorable window material for the present purposes. On the basis of the simulation, characteristics of the 0.25 mm thick beryllium foil was experimentally investigated by using tritium gas diluted with deuterium gas. The bremsstrahlung counting rate was proportional to the concentration of tritium above 1x10-5 Ci/cm3, and also sensitivity increased above 500 times in comparison with a case of former glass tube. On the other hand, it was seen that the counting rate was affected by the total pressure of the gas containing tritium. Namely, above about 50 Torr, the counting rate decreased gradually with the total pressure. Such behavior was interpreted in terms of the self absorption of β-rays in the gas phase. It was revealed that the change in the counting rate can be fully reproduced by a exponential function taking into account the self-absorption.
富山大学の論文