An Affordable Optically Stimulated Luminescent Dosimeter Reader
W.G. West; K.J. Kearfott; and A.F. Kalchik (The University of Michigan, Department of Nuclear Engineering and Radiological Sciences)
Optically stimulated luminescence (OSL) dosimetry using aluminum oxide doped with carbon (Al2O3:C) has become a widely-used and effective medium for personnel dosimetry applications. The OSL phenomenon involves the illumination of an irradiated sample of an appropriate material to produce a stimulated emission of light whose intensity is indicative of the radiation dose. While similar in underlying theoretical considerations to thermoluminescent dosimetry (TLD) processes, this dosimetry modality requires considerably different experimental apparatus to perform successfully. Commercially-available OSL readers exist, but may be too expensive for many labs desiring to begin research into this field. Furthermore, these readers have been developed primarily for geological dating applications and thus offer limited flexibility for researchers who may want to experiment with a variety of excitation light sources, light detection systems, or other aspects of an experimental setup. Faced with these considerations, researchers at the University of Michigan Radiological Health Engineering Laboratory have designed and constructed a lower-cost OSL reader with increased flexibility for pursuing laboratory research into OSL theory and application. Various methods were used to reduce costs and increase flexibility, including the use of off-the-shelf optical components; selection of newer higher-power light emitting diodes (LEDs) versus more elaborate light sources such as lasers or broad-spectrum bulbs with monochromators; and design features that allow simple and rapid changing of key system components. This reader design allows the use of more wavelengths of excitation light than current commercial readers, as well as the ability to swap out filters and other components in the midst of an experiment. In spite of these advantages, the total cost of the unit (approximately $6000) is an order of magnitude lower than commercial alternatives.