A quantitative passive technique for assay of near-surface tritium in materials

The electrons emitted when tritium β decays can be used to determine the amount of near-surface tritium in materials. A tritium contaminated sample is placed near a channel electron multiplier (CEM) in a vacuum chamber. If information is available about the depth distribution of tritium in the material, energy analysis of the electrons emerging from the surface allows and absolutely calibrated, noninvasive assay of the amount of tritium near this surface. The assay apparatus is described, and the method for relating the CEM counting rate of a given sample to its tritium content is explained. Comparisons with experiment are presented