Development of a compact mercuric iodide radiation intensity counter

Constellation Technology Corporation has developed a pocket-sized radiation intensity counter (RIC) for monitoring ambient radiation levels, search ac tivities, and customs inspection. The RIC incorporates a sensitive 2.5 cm x 2.5 cm x 0.5 cm mercuric iodide (HgI2) detector operating at roam temperat ure. The instrument provides the user with a visual indication of the gamma -ray count-rate by means of a 7 segment bargraph scale arranged in a semi-l ogarithmic scale. An alarm alerts the user when the count fate exceeds a pr e-selected level. Power is supplied by two commonly available AA alkaline b atteries. Total power consumption <2 mW and the battery life is estimated t o be >3 months under continuous use. The design of the RIC is described in detail and results of testing sensitivity, positional response, power consu mption, and temperature stability are presented. (C) 1999 Elsevier Science B.V. All rights reserved.