Preparation of composites of topaz embedded in glass matrix for applications in solid state thermoluminescence dosimetry

Natural colourless Brazilian topaz was combined with commercial silica glass to produce composites of topaz-glass for application in dosimetry. The preparation of the composites involved the following steps: (i) the glass and the natural topaz were milled; (ii) the glass and the microcrystals were mixed in specific proportions; (iii) pellets were prepared by uniaxial pressing and (iv) the pellets were sintered to produce the ceramics. Dosimetric performance was tested for γ-rays (137Cs and 60Co), X-rays (6 MV) and β-rays (90Sr/90Y) radiation fields. The topaz-glass composite presented a TL response in a large dose interval, reduced sensibility to visible light, slow fading of the TL glow curves, possibility of successive uses and a simple pre-irradiation annealing at 400 deg. C for 1 h