A New TL Extremity Dosimetry System Optimised for Routine Personnel Monitoring

A new TL extremity dosimetry system optimised for routine personnel monitoring is presented. It was developed at GSF, based on several GSF patents, and consists of a flexible plastic strip type detector holder with permanent ID code containing the phosphor and a PC controlled standard TL reader. The holder is prepared for single use and designed as a finger ring of adjustable size. It is comfortable to wear even under surgical gloves, water and solvent proof, heat resistant up to autoclave temperatures and can be used with all common TL detectors, limited only by their size. Each phosphor is labelled with an automated readable permanent ID code using a newly developed technique for direct inscription of TL crystals, to allow an individual calibration before application. The software controlling the TL reader includes a computerised glow curve deconvolution (CGCD) algorithm for data analysis and a database system. The CGCD algorithm replaces all annealing procedures in additional furnaces and saves up to 65% processing time at the GSF personnel monitoring service, when using LiF:Mg,Ti (TLD-100) TL detectors. The modular system design gives the possibility of modifying all equipment parts, e.g. detector holder, phosphor or TL reader, for the combined use with components from TL systems commonly used at monitoring services. The extremity dosemeter is type tested by the Physikalisch Technische Bundesanstalt (PTB) and is in routine use at the official personnel monitoring service of GSF. (author)