Thermoluminescence Studies On Hpht Diamond Crystals Exposed To Beta-Irradiation

A study of the thermoluminescent response of commercial synthetic high pressure high temperature (HPHT) type-Ib diamond crystals is reported. In previous works, it was found that the thermoluminescence (TL) glow curves of HPHT diamonds are non-reproducible. In this work, we compare the TL of samples irradiated with beta-radiation (5.4Gy min(-1)) before and after a stabilization procedure (SP) which includes a high gamma-dose irradiation (500 kGy) and a thermal treatment (TT) at 1073K for 1 h in N-2 atmosphere. McKeevers method and Kitis general kinetics order were used, identifying four peaks around 389, 465, 507, and 567K before the SP which shifted to lower temperatures around 373, 455, 489, 527K after the SP and the rise of a new TL peak around 620K. Before the SP both the TL and afterglow (AG) signals presented irregular dosimetric behavior, especially the low temperature TL peaks (373 and 455K). The uncertainty associated to TL reproducibility was of 12%. After the SP cycle, the TL and AG showed an enhancement in their linear dosimetric response between 0.09 and 1Gy, reaching saturation around 2Gy. The TL reproducibility was significantly improved with deviations around 3%, and a better behavior of TL fading was observed. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim