Estimation of tritium depth profile in zirconium by β-ray-induced x-ray spectrometry

The usefulness of the recently developed β-ray-induced x-ray spectrometry (BIXS) for nondestructive measurements of tritium captured in matrix was investigated using zirconium as a model sample. Two distinct spectra from characteristic and bremsstrahlung x-rays were clearly observed for the Zr sample exposed to tritium gas at room temperature. The former x-rays showed a sharp intense peak, while the latter x-rays formed a broad continuous spectrum. The intensity of both peaks decreased sharply with vacuum heating. At the same time, the top of the bremsstrahlung x-ray peak shifted to the higher energy side. These results indicate that the absorbed tritium diffused into the bulk by heating in vacuo. The changes were analyzed by computer simulation. The computer simulation could reproduce the observed spectra quite well. BIXS is therefore thought to be a highly promising technique for nondestructive determination of tritium inventories and depth profiles in materials. (author)