Synthesis and thermoluminescence characteristics of gamma and proton irradiated nanocrystalline MgB4O7: Dy, Na

This paper investigates the use of nanocrystalline MgB4O7: Dy, Na thermoluminescent (TL) dosimeter synthesized by the combustion method for the assessment of proton beam and gamma radiation doses, primarily on the shape of the TL glow curves. TEM and XRD studies revealed that the particles were tubular in shape and approximately 50 nm in size. The heating rate which affects the thermal quenching as well as the annealing temperature of the material was optimized. Samples in pellet form were irradiated by 150 MeV proton beams (1-450 Gy) and also with gamma rays (0.1-1000 Gy) for comparison. Trapping parameters of proton beam and gamma-irradiated materials were also obtained after deconvolution of the glow curves. In case of gamma-irradiation the nanophosphor showed an intense TL glow peak at 400 K and a small peak at 512 K, however in case of proton irradiation the nanophosphor showed a peak at 477 K and a small shoulder at around 450 K. The dose response curve of the nanophosphor for proton irradiation was found to be linear up to 350 Gy with a slight supralinearity for higher doses whereas the nanophosphor's gamma dose response was found to be linear up to 1000 Gy with a slight saturation towards the end dose. Photoluminescence excitation and emission spectra of the sample were also studied. Fading and reusability studies of the nanophosphor further confirmed the phosphor's suitability for radiation dosimetry. (c) 2012 Elsevier B.V. All rights reserved.