A personal discriminating monitor for tritiated water vapor

A personal monitor for tritiated vapor in air based on scintillation is bei ng developed by the Polytechnic of Milan and JRC of Ispra. A thin hygroscop ic salt layer has been laid on the flat surface of a solid scintillator mou nted inside the monitor. A small pump continuously supplies the monitor wit h filtered air samples taken from the room. The tritium oxide (HTO) in the air flow is reversibly trapped on the hygroscopic surface. A fraction of th e beta particles emitted by tritium produces scintillation light in the sol id scintillator which is detected by a miniaturized photomultiplier tube. T he monitor can reveal HTO air contamination as low as 8 x 10(5) Bq m(-3) - which is one-tenth of the limit for workers - in a short time (150 s). Seve ral tests have been performed to check instrument response linearity and de lay, the sensitivity to tritium and gamma-rays and the influence of other p arameters such as air flow rate, relative humidity, vibrations and shocks. (C) 2000 Elsevier Science B.V. All rights reserved.