LOW-ENERGY BETA-SPECTROSCOPY USING PIN DIODES TO MONITOR TRITIUM SURFACE CONTAMINATION

We show that tritium betas emitted from a surface can be counted using a pin photodiode as a solid state charged particle detector. Furtherm ore, we show that the range of tritium betas through air is sufficient to allow measurement of tritium on samples in air by this method. The se two findings make possible a new method to survey tritium surface c ontamination which has advantages over existing methods. We have built and tested several prototype instruments which use this method to mea sure tritium surface contamination, including a compact portable unit. The design of these instruments and results from tests and calibratio ns are described. Potential applications of this new method to monitor tritium are discussed.