Tritium inventory measurement by beta scintillation detection

A new design for a beta scintillation detector (BSD) has been developed for measurement of tritium partial pressure and total-tritium concentration in HDT-He process samples. The tritium beta energy deposited in the CaF/sub 2/[Eu] scintillation crystal produces light that is measured by a photodiode and electrometer producing an output voltage linearly proportional to the partial pressure of tritium. Mole percentage of tritium in unknown and standard samples is calculated from the ratio of BSD tritium partial pressure to the total sample pressure measured by a capacitance diaphragm gauge. Daily calibration to determine a new sensitivity S[V/Torr-T/sub 2/] using a single standard HDT-He mixture produces analyses with errors typically less than 1.3 percent of value as determined by analysis of other standard mixtures over a one year period. This error of tritium measurement is monitored with a measurement control program at Los Alamos to assure accuracy for all tritium inventory samples measured by this method.