Electret personnel dosemeter

An electret is a piece of dielectric on which charge has been stored quasi-permanently. A Teflon electret of diameter 50 mm and thickness 1 mm mounted in a bakelite chamber of volume 27 ml forms a simple dosemeter. It is further enclosed in a PVC bag with a clip so as to form an electret personnel dosemeter. The dosemeter is linear over a range of 0 to 0.018 Gy (1.8 rad) with a minimum resolvable dose of 0.09 mGy (9 mrad). It is found to be energy independent for photons down to 29 keV. The maximum directional error is about 15% down to 79 keV and is about 20% down to 29 keV of photon energy. (author)