Characteristics of a promising tritium process monitor detecting bremsstrahlung X-rays

Shu, Wataru; Matsuyama, Masao*; Suzuki, Takumi; Nishi, Masataka

The characteristics of a promising tritium process monitor using a NaI(Tl) scintillation detector for X-rays was examined with pure tritium in a concentration range of 10-10GBq/m. The measurement of tritium concentration was achieved by observing the bremsstrahlung X-rays generated by the interaction between the tritium beta particles and a gold film coated on the inside of beryllium window. A linear relationship between the counting rate of bremsstrahlung X-rays and the tritium concentration was observed for tritium concentration range of 10-10GBq/m, and the sensitivity of the monitor was determined to be about 0.5GBq/m per cpm in this concentration range. The characteristics were also investigated with a tritium mixture diluted with deuterium (atomic ration of tritium: 0.83%), and He release from a uranium bed during heating was traced with this monitor.