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In the present study, the precipitation method was used to synthesize microcrystalline Nd-doped CaSO 4 phosphor. Structural and morphological analysis of the phosphor samples were performed by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. In addition, luminescent properties of the samples were characterized by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The results of XRD analysis and SEM images showed that the prepared CaSO 4 :Nd powder samples have an orthorhombic crystal structure and almost spherical in size with an average between 3 and 17 μm. In the light of the luminescence analysis, the optimum preheat temperature required to evacuate the low temperature electron traps was determined as 170 °C. It was also presented that CaSO 4 :Nd samples have the potential to be used as a dosimetric material with a linear dose sensitivity between 1 and 20 Gy (as TL dosimeter), and 1 and 10 Gy (as an OSL dosimeter) when they are exposed to beta irradiation. In addition, the full width at the half maximum (FWHM) values of the main TL peaks presented no independence of HR. • Nd-doped CaSO 4 phosphors were synthesized by using the precipitation method. • Structural, morphological and luminescent properties of CaSO 4 :Nd were determined. • CaSO 4 :Nd is almost spherical in size with an average particle size in the range of 3–17 μm. • CaSO 4 :Nd samples have a linear dose sensitivity between 1 and 20 Gy (as TL dosimeter) for beta irradiation. [ABSTRACT FROM AUTHOR]

The effect of heating rate (HR) on thermoluminescence (TL) glow curves of 1%, 4%, and 10% Ce 3 + doped ZnB 2 O 4 phosphors was investigated in detail. The glow peaks are examined and, activation energy ( E ) and frequency factor ( s ) are determined by using various heating rate (VHR) method. In the obtained glow curves with nine different HRs between 2 and 10 °C/s, it was observed that the TL intensities of the first peaks of all three samples and the second peak of 10% Ce 3 + doped sample decrease with increasing HR. The decrease in TL intensity was investigated whether it may be due to the presence of thermal quenching or not. On the other hand, the second glow peaks of 1, 4% Ce 3 + doped ZnB 2 O 4 phosphors show an anomalous TL behavior, which the probability of the radiative processes increases due to recombination of free electrons, so the TL intensity increases with the HR. The graphs of full width at the half maximum (FWHM) versus HR were also plotted to evaluate the influence of HR on TL intensity. In this paper, we suggest that the non-localized Schön – Klasens model may give an explanation for the second peaks of 1, 4% Ce 3 + doped ZnB 2 O 4 phosphors showing an unexpected increase with the increasing HR. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.47–0.53 eV for peak 1 and 0.61–0.66 eV for peak 2. However, s values of Ce 3 + doped ZnB 2 O 4 phosphors were found slightly different according to the dopant amount and the equation used. Furthermore, different amount of Ce 3 + doped samples indicate the similar properties for the repeated cycles of 5 Gy in the same irradiation conditions. [ABSTRACT FROM AUTHOR]

The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB 2 O 4 phosphors (i.e. ZnB 2 O 4 :0.01La, ZnB 2 O 4 :0.02La, ZnB 2 O 4 :0.03La and ZnB 2 O 4 :0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB 2 O 4 :La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200 °C and a shoulder peak at around 315 °C with a constant heating rate of 5 °C/s. The kinetic parameters of ZnB 2 O 4 :La phosphors TL glow peaks (i.e. order of kinetics ( b ), activation energies ( E a ) and frequency factors ( s )) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of E a obtained with these methods for ZnB 2 O 4 :La phosphors are consistent with each other, but the s values differ considerably. [ABSTRACT FROM AUTHOR]

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]