Study of graphite-mixed and boron-diffused TLDs for skin dose assessment

A personnel dosimeter for whole body skin dose assessment requires a detector-filter combination capable of estimating tissue dose at a depth between 5 and 10 mg cm-2 below the surface of the skin. In principle the ideal dosimeter comprises a tissue-equivalent detector of 5 mg cm-2 covered by a tissue-equivalent material of the same thickness. However, difficulties in handling very thin dosimeters combined with a low sensitivity have so far generally excluded the application of these dosimeters for routine monitoring. Practical TL-dosimeters with a thin effective dosimeter thickness can be achieved by (1) fixing a thin layer of thermoluminescent material onto a non-thermoluminescent base (2) changing the transparency to TL dosimeters by addition of graphite in the production process and (3) creating a new glow peak in a thin surface layer of existing LiF TLDs using a boron diffusion process. Dosimetric properties of graphite-mixed and boron-diffused TLDs have been reported earlier and this paper deals with results obtained from further investigations of the applicability of these dosimeters for skin dose assessment in routine personnel monitoring