PROCEEDINGS OF THE 6 th SRP INTERNATIONAL SYMPOSIUM, Southport 1999, pp. 455-458 CHARACTERISTICS OF TLD-100 DETECTORS USED IN PERSONNEL DOSIMETRY Radu A. Vasilache, Mariana Cismasu Institute of Public Health, 1-3 Dr. Leonte St., RO-76256 Bucharest-35, Romania ABSTRACT In 1994, within a Technical Co-operation Project with the International Atomic Energy Agency, the Institute of Public Health Bucharest received a Harshaw 6600 TLD System, with the aim to replace the film-badge by TLD cards for the individual radiation monitoring in radiation medicine in Romania. Before replacing the film badges with TL dosemeters, we performed a very thorough study on the characteristics of the TLD-100 detectors that were going to be used. The paper presents only two of the characteristics of the dosemeters: the angular dependence of the dosemeter response and the fading. A special attention has been given to the fading characteristics, and a number of experiments to determine if the fading could be compensated by exposing the unannealed detectors to UV radiation. INTRODUCTION Since 1965, the applications of thermoluminescence to radiation dosimetry have become widespread. TL dosemeters are now widely used in medical and health physics, due to a large number of advantages such as small dimensions, easy handling, etc. In Romania, the Personnel Dosimetry Laboratory of the Ministry of Health used film-badge dosemeters since 1965 for personnel monitoring. Before switching to TLDs, a thorough study of the characteristics of the TLD-100 detectors used for personnel dosimetry had to be made. The paper presents the results of two sets of experiments conceived to determine the angular dependence of these detectors and the fading characteristics of the detectors. METHOD AND MATERIALS All the experiments were performed with a batch of 200 TLD-100 dosemeter cards (supplied by Harshaw Chemical Co.), with LiF:Mg,Ti encapsulated in Teflon. The dosemeters had similar responses to radiation (the variation between the calibration coefficients of the TLD elements was less than 8%). The readings were performed with a Harshaw 6600 TLD Reader, with photomultiplier tube noise and reference light source readings checked after each 10 dosemeter readings. All readings and glow curves were stored in a computer system then analysed.