HT/HTO MPC detector response under field conditions

A unique rapid tritium-in-air monitor was developed at the Lawrence Livermore Laboratory which will detect tritium in air in proportion to Maximum Permissible Concentration (MPC) values for both HT and HTO. This paper dwells on the actual operating experience of the detector in the tritium scrubber room at the Rotating Target Neutron Source Facility at Lawrence Livermore National Laboratory where there is a possibility of HTO and HT in various concentrations and at various multiples of MPC. To test the instrument response to potential mixtures, the scrubber system lines were tapped and the air monitored by the HT/HTO tritium detector and by a double ion chamber detector system (two ion chambers separated by a molecular sieve). The overall response of the MPC detector is shown in reference to the ion chamber system. The MPC detector was found to rapidly distinguish between HT and HTO for multiples of tritium-in-air MPC from 10 to 106. In addition, it was found to be rugged and reliable