Analysis and development of optical methods to re-use optical stimulated luminescent dosimeters

Abstract

Optically Stimulated Luminescence (OSL) is a worldwide used technique in ionizing radiation dosimetry applications, such as personal and environmental monitoring. At the CDTN-CNEN facilities is produced a ceramic detector of α-Al2O3:C, which is used in the routine environmental monitoring and for research purposes. In order to reuse these detectors, it was developed, at Luminescent Dosimetry Laboratory an optical bleaching device, which can operate with green and blue LED illumination modes. The present work describes the use of such device to bleach the optically accessible traps, taking the detectors to its background signal levels. Reference dosimeters α-Al2O3:C commercial and magnesium tetraborate were used also for comparison. As a general procedure, before any irradiation, the used detectors were optically bleached by 36 hours. For the best efficiency of bleaching, after irradiation, the ceramic and commercial aluminum oxide detectors were optically bleached under blue LED light for 3 and 6 hours, respectively. For tetraborate detectors, the required time of optical bleaching was 2 hours, under blue LED illumination.