Comparison of the dosimetric response of 4-elements OSL and TL passive personal dosimeters

Abstract

IntroductionThermoluminescent dosimeters (TLD) made from LiF:Mg,Ti (manufacturer: Thermo Fisher Scientific, USA, brand name: TLD-100) and optically stimulated luminescence detectors (OSLD) made from BeO (manufacturer: Dosimetrics GmbH, Germany, brand name: BeOSL) are used as passive personal detectors. Although differences exist between them, mainly in terms of handling, reading, material response and dose algorithms, both systems have to satisfy some specific requirements. The aim of this study is to verify that the 4-element version of both dosimeters match the IEC 62387 requirements for photon fields, and to compare them. Materials and methodsThe LiF-TLDs tested were those provided by the Spanish National Dosimetry Centre (CND), which makes use of an in-house dose calculation algorithm. The BeO-OSLDs were those distributed by Dosimetrics. The following features were evaluated for photon radiation: coefficient of variation, non-linearity, photon angular and energy dependence, reusability, dose build-up, fading, self-irradiation and response to natural radiation, as well as accuracy of energy estimation. For the BeO-OSLDs the consistency between consecutive re-readings was also determined. ResultsBoth systems satisfy the IEC 62387 requirements for the tests described above. One of the main advantages of the BeO-OSLDs over the LiF-TLDs is their lower energy dependency and higher reusability. They are also easier to manipulate, read and prepare. On the other hand, advantages of the LiF-TLD system over the BeO-OSLD system are the more accurate energy estimations provided by the CND dose algorithm, which are used to correct the higher energy dependency, and the glow curves provided by the TL readers. ConclusionThe LiF-TLDs and BeO-OSLDs tested satisfy the dosimetric requirements for their use as passive personal dosimeters in photon fields. For this reason, a study of the simplicity, reusability, amount of dosimeters read each month or automation in the handling and reading process can be helpful to decide the best option. The choice between one of them from a dosimetric point of view might also depend on the importance given to the different criteria here studied.