Beryllium oxide as optically stimulated luminescence dosimeter

In the last years a dosimetric system using optically stimulated luminescence (OSL) of beryllium oxide (BeO) was developed by the radiation physics group in Dresden. Blue light LED stimulation and reading of luminescence light with an enclosed photo sensor module are performed from opposite detector sides. A software controls stimulation, records the amplified and digitized photo sensor signal and generates an unified OSL signal. With the help of calibration these OSL signal can be used to specify dose. The linearity of dose response reaches from μGyμGy level up to a few Gy. At higher dose the OSL signal shows a saturation which can be correctly described by a saturation function up to 100 Gy. Fading of the signal is negligible. The material BeO has an excellent resistance to environmental influences. Due to the near tissue equivalence and the resulting low photon energy dependence the BeO detectors are predestinated for dosimetric use. Assembling several detectors to an area offers the ability to examine strongly inhomogeneous radiation fields. Measurements of the radial dose function of a brachytherapy seed and dose rate distributions in front of a Fe55 source are presented.