Stability of Nal(Tl) detector for tritium monitor of BIXS use to hot environment

Kawamura, Yoshinori; Shu, Wataru*; Matsuyama, Masao*; Yamanishi, Toshihiko

Assuming the blanket sweep gas at the outlet of the blanket, tritium gas monitor by -ray induced X-ray spectroscopy has been modified, and has measured tritium at 120 C. The counting rate at 120 C was about 1/2 of that at the room temperature. In this work, the measurement system was a closed system. When two systems have same volume and same pressure, the number of molecules in higher temperature system is smaller. This is one of the causes of small counting rate. The deterioration of the scintillator after heating was not observed.