Feasibility of β-ray induced X-ray Counting Method to In-situ Measurement of Tritium Contamination

To conduct in-situ and real-time measurements of contamination due to tritium adsorption/desorption on the surfaces and in sub-surface layers of materials, a new measuring method was established. The method is principally based on measurement of X-rays induced by β-rays from tritium. To assess the applicability of the present method, a graphite sample in which was implanted a given amount of tritium was used as a model. After tritium implantation, measurement was carried out using an ultra-low energy Ge detector under air or argon atmosphere. In the latter atmosphere, a sharp and strong characteristic X-ray peak attributed to K-transition of Ar appeared at 2.96 keV along with a broad bremsstrahlung X-ray spectrum, indicating X-rays more penetrating thanβ-rays to be effectively generated by substitution of argon and contamination to be easily evaluated by conventional X-ray detectors without special detectors forβ-ray counting. Accordingly, it was revealed that the present method is valuable for in-situ and real-time measurements of surface contamination due to tritium exposure owing to high durability and reliability, simple construction and ease of maintenance