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• NaBaBO 3 :Ce3+ phosphor is synthesized by a combustion method. • Thermoluminescence properties were conducted. • Activation energies were calculated using IR, Booth-Bohun-Parfianovitch, VHR and CGCD methods. NaBaBO 3 samples incorporated with various concentration of Ce3+ were prepared by combustion method. The influences of rare earth doping in synthesized samples were analyzed by X-ray diffraction (XRD). Optimum doping concentration of NaBaBO 3 :Ce3+ is 0.5 %. Thermoluminescence (TL) kinetic analysis using T m -T stop , initial rise (IR), variable heating rate (VHR) and glow curve deconvolution (GCD) methods were performed on the glow curves of NaBaBO 3 :Ce3+ phosphor material. The T m -T stop analysis revealed that the whole glow curve measured without preheat of the prepared sample is composed of at least six overlapping glow peaks. The number of the glow peaks required to provide best fit to the glow curves of the sample are also estimated using GCD method and one found six glow peaks at all doses (FOM ≤ 1.84 %), which are similar to those from T m -T stop analysis. The dose response of NaBaBO 3 :Ce3+ phosphor sample exposed to beta irradiation is linear up to 10 Gy. The results from experiments indicates that main dosimetric peak of NaBaBO 3 :Ce3+ follows first order kinetic model, which was also supported by dose response plot. The Z effective value of this phosphor is calculated to be 46.66. Present findings confirm that NaBaBO 3 :Ce3+ phosphor sample is a promising candidate for applications in environmental dosimetry as one depicts good TL dose response with adequate sensitivity and linearity. [ABSTRACT FROM AUTHOR]

Abstract NaBaBO 3 host material was synthesized using the combustion method. In order to optimize the performance of the material, effects of sintering temperatures varying from 600° to 1000 °C were investigated. The sintering temperature and dwell time were found to have pronounced effects on the pure NaBaBO 3 material. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to confirm the phase formation and examine the surface morphology of the prepared powder material, respectively. TL behavior of NaBaBO 3 was studied at various beta doses. It is seen that the sample exhibits well resolved TL glow peak at a peak temperature about 175 °C and corresponding TL intensity increases with the increasing beta dose. However, TL glow peak slightly shifts to lower temperature with the increasing beta dose level. This is the first TL report of a phosphor with a NaBaBO 3 host. The TL kinetic parameters were estimated by the peak shape (PS) method and CGCD software. TL glow curves of NaBaBO 3 consist of several traps and exhibited second order kinetics. A possible TL mechanism was also discussed using the energy level model. The obtained results can provide valuable knowledge related to the investigation of the intrinsic nature characteristics of NaBaBO 3 in research fields pertaining to dosimetry. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of different heating rates (HRs) on low and high temperature thermoluminescence (TL) glow-peaks, reusability properties, and the kinetic parameters (activation energy ( E ), frequency factor ( s ) and order of kinetics ( b )) of 1%, 4% and 10% La-doped ZnB 2 O 4 phosphors. All La-doped ZnB 2 O 4 phosphors have two characteristic TL peaks at around 80–85 °C and 150–160 °C. The experimental results show that the TL glow-peak temperatures (T M ) shift to higher temperatures for all doped materials as the HRs increase because of the temperature lag effect. The maximum peak intensity ( I M ) decreases for the first peak of 1% doped, remains roughly constant for second peak of 1% and both peaks of 4% doped, and increases for both peaks of 10% La-doped ZnB 2 O 4 samples as the HRs increases. Differences between the intensities of various amounts of La-doped phosphors were explained with anomalous HR phenomenon except the first peak of 1% La-doped ZnB 2 O 4 which was clarified by thermal quenching effect. In this study, the temperature dependence of the recombination rate of released carriers during the heating process by increasing the doping concentration of La might explain the peaks of the glow curves, which shows an unexpected behavior with the increasing HR values. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.62 – 1.03 eV for 1%, 0.65 – 1.15 eV for 4%, and 0.69 – 1.01 eV for 10% La-doped phosphors. However, s values were found slightly different related to the dopant amount. Furthermore, different dopant amounts indicate the similar and reasonable properties for the repeated cycles of 5 Gy with the same readout conditions. [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]