A model for distinguishing between static and dynamic exposure of personal thermoluminescence dosimeters

To distinguish between static and dynamic (normal) exposure of personal TL dosimeters, a model of radiation deposition and of TL light transport in the TLD dosimeter is proposed. The RADOS dosimeter badge using MCP-N (LiF:Mg,Cu,P) TL detectors with standard filters replaced by special Pb and Cu filters with a pattern of holes or inserts was modelled. The photon radiation transport in the dosimeter and energy deposition in the TL detector were simulated by the Penelope Monte Carlo transport code. The model of TL light transport within the TL pellet takes into account the distribution of energy deposition in the TL detector, light self-absorption in the detector and reflection of TL light of the heating planchet. The shape and hole pattern of the filters were optimized with respect to best distinction between static and dynamic exposures. The results of calculations were verified experimentally by exposing RADOS badges with modified filters to beams of low energy X-rays directed at various angles.