The use of beryllium oxide thermoluminescence dosemeters for measuring gamma exposure rates

Beryllium Oxide (BeO) is shown to be the best thermoluminescence dosemeter (TLD) for measuring gamma exposure rates in graphite moderated reactors. It has an almost negligible response to thermal neutrons and the correction for the unwanted fast neutron response is small. The experimental procedure is described and is based on TL from a glowpeak at 3000C rather than that at 1900C, which is usually used. The variation of response of BeO as a function of photon energy has been measured for TLDs built up in graphite, a medium to which they are well matched dosimetrically, and within aluminium and steel. The rsults are compared with calculated cavity effects which are shown to be insufficient to describe the measured energy dependence. TL effects in the material appear to dominate. (Auth.)