MONITORING OF ENVIRONMENTAL RADIATION-LEVELS USING TL PHOTON-COUNTING SYSTEM WITH CASO4-DY PHOSPHOR

With CaSO4:Dy (0.5 mol %) encapsulated in glass capillaries, each containing 15 mg of the TL phosphor, it is possible to measure gamma radiation exposures up to a lower limit of 2.6 × 10-8 C/kg employing the thermoluminescent photon counting technique. Bare glass capillaries, without any additional energy compensating filter, having enhanced response due to the contribution from low energy components of the background gamma radiation, can be usefully employed to monitor environmental gamma radiation levels and even day-to-day variations in the background. The energy weighted correction factor for CaSO4:Dy is derived from the background gamma spectrum measurements with a 3″ × 3″ NaI(T1) scintillator. At two locations of Trombay, the radiation level was measured to be 2.86 × 10-9 C kg·h. © 1979.