Activity monitoring of a gaseous tritium source by beta induced X-ray spectrometry

For monitoring and control of gaseous tritium sources in fuel circulation systems of fusion reactors beta induced X-ray spectrometry (BIXS) seems to be an applicable method. The characteristics of a BIXS monitoring setup built at TLK were examined. A low-noise silicon drift detector (SDD) was used together with two thin beryllium windows evaporated with gold films of 100 nm for efficient X-ray production. The measured X-ray intensity was proportional to the tritium partial pressure and the average detection efficiency was evaluated as 32.6 × 10−8 cps/Bq. A tritium memory effect was revealed. From the results it was concluded that such a monitoring system would be a useful complement for tritium analytics devices if well designed in terms of memory effect suppression.