A tritium-in-air monitor with compensation and additional recording of α-, β-, and γ-backgrounds

The development of a computer-controlled tritium-in-air monitoring using flow-through air proportional counters as the detector is described. Combining automatic compensation for β- and γ-backgrounds with α-background discrimination, the monitor can detect tritium activity separately from other radioactive gases. The computer calculates and prints out not only tritium concentration in air but also dose equivalent rate by external γ-rays and/or activity concentrations of other radioactive gases than tritium in real time. Since the monitor has a wide range of 0.005-5000 Bq/cm³ (6 decades) and a short response time of several minutes, it can be used effectively to monitor tritium in air in fission and fusion reactor environments