A Sampling System for Atmospheric HT and HTO

A system is briefly described, which is designed for the sampling of tritium gas (HT and T2) and tritiated water vapor in the air at levels far below MPC and down to present-day atmospheric background levels. The tritium gas is extracted from the air by catalytic combustion on Pd at ambient temperature. The resultant water is absorbed on molecular sieve carrying the Pd. The system is well suited for field work. Present-day world-wide HT levels are about 2.3 pCi/kg air, and the HTO levels about the same in the troposphere.