Investigation of a BeO-based optically stimulated luminescence dosemeter

Abstract

The optical sensitivity of BeO-based luminophors has been well-known for many years. The optical stimulation of BeO with blue light is most effective. Then the dosemeters emit luminescent light in the ultraviolet-range around 325 nm. Matched on these facts a simple optically stimulated luminescence (OSL) treatment has been developed. Intense blue light-emitting diodes are used for cw-stimulation. A Hamamatsu solar blind photomultiplier detects the OSL-light. Good separation of both spectral ranges by optical filters is very important. The dosemeter has a linear dose response between approximately 20 muGy and >10 Gy. It was suggested, that a modification of stimulation conditions would allow measurements down to 1 muGy. Fading, photon energy dependence and reproducibility of OSL-signal correspond well with requirements to clinical and personal dosemeters. In addition, basic questions of the OSL-process in BeO have been investigated. A relevant point of interest was the dependency of the OSL-signal on stimulation power.

Measurement of radiation dose with BeO dosimeters using optically stimulated luminescence technique in radiotherapy applications

“…Ceramic beryllium oxide (BeO) has been investigated as a OSL material; however, studies have drawn attention that it can be also used as a TL dosimeter (Sommer and Henniger, 2006;Sommer et al, 2008). BeO is sensitive to ionizing radiation, and has an effective atomic number (Z eff ¼7.2) similar to water (Z eff $ 7.51).…”

“…The fading of OSL signal in BeO is approximately 6% when compared 30 min after radiation, and is o1% when stored at 50°C for the next 6 months (Sommer and Henniger, 2006). Shallow trap centers that are associated with unstable signals can be emptied with a short preheating period before signal reading.…”

“…Shallow trap centers that are associated with unstable signals can be emptied with a short preheating period before signal reading. Sommer and Henniger (2006) have suggested 5 min at 50°C; Bulur and Göksu (1998) have used 125°C for heating.…”

TL, OSL and ESR studies on beryllium oxide

“…These BeO luminescent chips are produced by sintering at high temperatures ( $ 1500 1C) in commercial laboratories. Recent investigations [1][2][3] of OSL characteristics of sintered BeO discs have clearly shown that in the optically stimulated luminescence (OSL) mode BeO has higher sensitivity than in the TL mode and its dose-response is linear from mGy level up to a few Gy. Thus, the OSL method offers a wide range of applications in radiation dosimetry.…”

“…Thus, the OSL method offers a wide range of applications in radiation dosimetry. Among the various types of BeO ceramics, Thermalox TM 995 (Brush Wellman Inc., USA) was identified [1][2][3][4][5] as one of the most popular forms of BeO for TL and OSL studies. BeO (Thermalox 995) shows three TL peaks at 75, 220 and 340 1C for glow curve recorded up to 400 1C (heating rate 5 K s À 1 ), 220 1C peak being the main dosimetry peak [1].…”