Photon energy response of an aluminum oxide TLD environmental dosimeter

Because of aluminum oxide´s significant advantage in sensitivity over LiF, minimal fading characteristics, and ease of processing, aluminum oxide thermoluminescent dosimeters (TLDs) are being phased in at Los Alamos for environmental monitoring of photon radiation. The new environmental dosimeter design consists of a polyethylene holder, about 0.5 cm thick, loaded with a stack of four aluminum oxide TLD chips, each 1 mm thick and 5 mm in diameter. As part of the initial evaluation of the new design, the photon energy response of the dosimeter was calculated over the range from 10 keV to 1 MeV. Specific goals of the analysis included the determination of individual chip response in the stack, assessment of the response variation due to TLD material (i.e., LiF versus Al₂O₃), and the effect of copper filtration in flattening the response