Response of thermoluminescence dosemeters to beta radiation and skin dose assessment

Abstract

The response of a TL dosemeter to beta radiation is heavily influenced by the absorption of the radiation in the dosemeter thickness. As a consequence, the assessment of skin dose depends either on the execution of a calibration with a beta field of the same characteristics as that to be monitored or on the knowledge of depth-dose distribution in the dosemeter. Depth-dose distributions have been experimentally estimated for optically transparent dosemeters in a number of irradiation geometries and with sources of different configuration and energy. General algorithms based on the point-source function of Loevinger have been developed, by which the response of TL dosemeters can be evaluated and skin dose correction factors derived. TLD responses to beta radiation calculated by the present method are in sound agreement with other author's measurements. The dependence of beta ray absorption on the configuration of source and the source-to-detector distance has been picked up. Variations of source-to-detector distance as large as 30% of the maximum beta range account for differences up to 40% in the skin dose correction factors for a 200 mg cm-2 thick dosemeter. The proposed scheme results in a useful tool in skin beta dosimetry using multiple TLDs behind different absorbers. In practical applications thick dosemeters may be used properly only in well-known radiation fields. Conversely, the described method allows an acceptable estimate of the skin dose error.

Beta energy dependence of the Ag-doped phosphate glass detector response

“…Ideally it thus would be important to measure a β dose with a detector 2 whose response is independent of the energy. Contento et al (1984) suggest in this case doing a calibration with a β field of the same characteristics as measured in the monitored area.…”

An improved HarshawTLD™ extremity dosimeter – DXTRAD beta ring

“…This makes it difficult to estimate the dose where the radiation field is unknown. Therefore, many products and designs of extremity dosimeters are aimed to overcome this difficulty (Contento et al, 1984;Dutt et al, 1986;Tawil et al, 1993;Perry et al, 1996;Bilski et al, 1996;Yuen et al, 1999;Christensen et al, 2001;Luo et al, 2002). The dosimeter described in this paper is an improved beta extremity ring that demonstrates good performance in many aspects while retaining wearability and protection from intrusion of biological and radiological contaminants.…”

Radiological impact assessment for workers on treatment of radioactive spent resin from heavy water reactors

“…14 C is more generated in heavy water reactor than pressurised water reactor because the concentration of 17 O and thermal neutron flux is higher. The 14 C nuclide contained in the spent resin is a long-lived nuclide with a half-life of 5 730 years with biological effects via a carbon metabolism reaction from internal exposure by respiration and ingestion [7][8][9]. Since these beta-emitting nuclides affect the human body over a long period of time, the safety evaluation of radiation workers is essential.…”