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In this study, the thermoluminescence (TL) characteristics of undoped and various Ce3+-doped Zn(BO2)2 powder samples excited by beta irradiation are reported for the first time. Zn(BO2)2:Ce3+ powder samples were prepared by the nitric acid method (NAM) using the starting oxides [zinc oxide (ZnO), boric acid (H3BO3) and doped element oxide (CeO2)]. The formations of the obtained samples were confirmed by an X-ray diffraction study. Dose responses of Ce3+-doped Zn(BO2)2 samples were investigated after the beta irradiation in the dose range from 143 mGy to 60 Gy. All TL measurements were made on using an automated Risø TL/OSL DA-20 reader. TL emission was detected through a filter pack (Schott BG-39 and Corning 7-59) transmitting between 330 and 480 nm. TL glow curves were obtained using a constant heating rate of 5°C s-1 from room temperature (RT) to 450°C in an N2 atmosphere. The dose response and minimum detectable dose (MDD) values of the samples were determined. The dose responses of all the samples tested exhibited a superlinear behaviour. MDD value of 4 % Ce3+-doped Zn(BO2)2 sample, which shows a high temperature peak at about 230°C, was determined as 96 mGy. MDD values for 1, 2, 3, 5 and 10 % Ce3+-doped Zn(BO2)2 samples were also determined as 682, 501, 635, 320 and 824 mGy, respectively. The trap parameters of undoped and 4 % Ce3+-doped Zn(BO2)2 samples were estimated by the computerised glow curve deconvolution method. [ABSTRACT FROM AUTHOR]

In this article, we have investigated the effects of pre-irradiation heat treatments on the thermoluminescence (TL) glow peaks of natural fluorite (CaF2) collected from the central Anatolia region of Turkey. A typical TL glow curve of phosphor consists of four clear glow peaks with maximum intensities occurring at temperatures around 100 °C, 120 °C, 190 °C and 290 °C for a sample irradiated to a dose of 48 Gy and readout at a heating rate of 1 °C/s. It was observed that the intensities of all the TL glow peaks are strongly sensitive to annealing temperatures and durations. Annealing at 450 °C for 15 min was found to be the best for reproducibility of experimental results. The dose-responses of individual TL peaks of this material were also examined after annealing at 450 °C for 15 min by β-irradiation to doses between 0.04 Gy and ≈10.4 kGy. It was observed that the total area and peak heights of all glow peaks showed similar trends with increasing radiation dose; first, they increased linearly up to ≈50 Gy and then saturation effects began above this dose value. The effect of heating rate on the TL glow peaks of the mineral was also studied and it was observed that the intensities of glow peaks are differently affected with variation in heating rate. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the thermoluminescence (TL) properties of natural CaF2 were investigated after β-irradiation at room temperature (RT). The additive dose (AD), T m(E a)–T stop, repeated initial rise (RIR), and computerized glow curve deconvolution (CGCD) methods were used to analyze the thermoluminescence (TL) glow peaks in natural CaF2 after β-irradiation between 0.015Gy and ≈2kGy dose level. These methods were used to determine the number of peaks and kinetic parameters (kinetic orders b, activation energy E a, and attempt-to-escape frequency s) associated with the thermoluminescence (TL) glow peaks of natural CaF2. The E a–T stop and CGCD methods indicate that the glow curve of this material is the superposition of at least six glow peaks, which were dealt with as P1–P6, in the temperature range between room temperature (RT) and 400°C. Dose variation experiments revealed that TL glow curve of natural CaF2 has both first and general-order glow peaks. The dose responses and fading process, which are very useful in radiation dosimetry, of individual TL peaks of this material were also examined. In addition, the influence of heating rates on the response of dosimetric glow peaks of natural CaF2 was studied. It was observed that the total area of glow peak and peak intensities of all glow peaks are continuously decreasing with increasing heating rate. [Copyright &y& Elsevier]

In this study, the thermoluminesce (TL) properties of natural onyx were determined after β-irradiation ( 9 0 Sr/ 90 Y) at room temperature. The effect of the additive dose and variable heating rate for TL glow peaks of the sample were investigated. Computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters related to the TL glow peaks in natural onyx from Turkey. It was also determined kinetic parameters of onyx by means of the variable heating rate (VHR) method. The sample was exposed to β-irradiation between 2.4 Gy and 2.457 kGy. The CGCD methods showed that the glow curve of sample is the superposition of at least six first order components which were ascribed as P1-P6. The dose responses of some peaks have similar patterns and they follow linearity. The effect of heating rates on the response of dosimetric glow peaks of sample was studied. The maximum TL peak intensities of glow curve are decreasing with increasing heating rate and maximum TL peak intensities at 1 °C/s drops to 20% of the initial value when the sample is read at 6 °C/s. [ABSTRACT FROM AUTHOR]

Abstract: The additive dose (AD), T m(E a)–T stop, repeated initial rise (RIR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods were used to analyze the thermoluminescence (TL) glow peaks in natural zircon after β-irradiation between the dose level 0.015Gy and ≈10kGy. The CGCD and E a–T stop methods indicate that the glow curve of this material is the superposition of at least seven glow peaks, which were referred to as P1–P7, in the temperature range between room temperature (RT) and 400°C. The dose responses and fading process of individual TL peaks of this material were also examined. The dose response behaviors of all peaks are different from each other and they are saturated at different dose levels. Peaks 1 and 2 completely disappeared after 1 month storage in the dark room at RT. On the other hand, the intensity of peaks 3+4 was approximately reduced to 80% of its original value whereas the other peaks (P5–P7) were not sufficiently affected during this period. [Copyright &y& Elsevier]