Portable devices for monitoring radon and its progeny in air

We have developed two kinds of portable monitoring devices to measure the concentration and potential energy concentration of radon and its progeny in air. The thermoluminescence material CaSO4 (Tm) is used as the detection element. One of the devices is called passive radon monitor. The lowest detectable limit for radon in air is about 1.5 Bq/m3, as a sampling time being one week. Good reliability and ease to operate are its main advantages. The second kind of device is called a working level monitor which consists of a miniature remembrane pump and an integrating sampling probe. The lowest detectable limit is about 0.00043 WL (9x10-9J/m3) for a sampling time of 6 hours. It weighs only 0.35 kg, but maintenance is necessary sometimes. (author). 6 refs, 2 figs, 4 tabs