On the Applicability of Camera Lens Protectors in Emergency Luminescence Dosimetry

In this work, the optically stimulated luminescence (OSL) properties of camera lens protectors and their potential use in emergency dosimetry were investigated. Camera lens protectors can be attached to mobile phones, which are commonly carried by individuals and may be useful in estimating an emergency dose. The presented results confirm the great potential of this type of glass material for dose determination. The glass protectors exhibit advantageous properties, such as linear dose dependence in the range of at least 0.6–10 Gy, minimum detectable dose at the level of tens of mGy, and good measurement repeatability for samples of the same type. Significant fading during the first day after exposure is an undesirable feature of tested glass. Nevertheless, the application of the correction for fading shows promising results in the dose recovery process.

Thermoluminescence Characteristics of Terbium Doped Zinc Borates

In this work, structural and thermoluminescence (TL) characteristics for ZnB2O4:xTb3+ (x = 0.01, 0.02, 0.03, 0.04, 0.05, and 0.10 mole) phosphors were investigated. The phosphors were prepared via synthesis of nitric acid. The X-ray diffraction (XRD) studies show that the synthesized samples can be indexed to nearly single-phase cubic ZnB2O4. The TL characteristics following 90Sr beta irradiation (40 mCi) were studied. TL intensity is found to depend on Tb concentration. The optimal concentration of the doped Tb3+ is 0.03 mol in TL measurements. TL dose responses of the phosphors to beta doses of 0.143, 0.715, 1.43, 15, 30 and 60 Gy showed fairly linear behavior. The minimum detectable dose (MDD) value for ZnB2O4:0.04Tb3+ was found to be 87 mGy. The kinetic parameters of the ZnB2O4:0.03Tb3+ sample were estimated by the glow curve deconvolution, the initial rise, the curve fitting, and the peak shape methods. The results indicate that these phosphors are thought to be promising candidates as TL materials. The results provide valuable knowledge of the characteristics of Tb-doped ZnB2O4 for use in dosimetry research.

Thermoluminescence response of electron and photon irradiated Zinc Borate Silica (ZBS) host glass system

Introduction: Glass phosphors are broadly used to determine patient doses in radiation diagnostic and radiotherapy because of their good features, the dose ranges of interest are approximately0.1 -100 mGy for clinical x-ray diagnostics, and 1-5Gy for radiotherapy. Materials and Methods: Borate silica glass samples were prepared using melt quenching technique, XRD analysis confirms that the glass system is amorphous (non- crystalline). TL properties of glass were investigated such as optimum concentration, heating rate, and annealing procedure. The optimum glass samples of 45ZnO-45B 2O3-10SiO2 are used as glass radiation dosimeter. The samples were irradiated using 6MeV and 6MV photon beams in adose range (0.5-4) Gy. Results and Discussion: There is single and wide thermoluminescence glow curve that offering with maximum intensity at about 165 oC. Linear dose-response behavior has been observed in this dose range for both irradiation electron and photon beam. Sensitivity and minimum detectable dose have been found. The sensitivity of 6MeV is 1.7 greater than the sensitivity of 6MV photon energy. Conclusions: The results point out that this glass has the potential to be used as an electron and photon radiation dosimeter.

Thermoluminescence and dosimetric characteristics study of quartz samples from Seyhan Dam Lake Terraces

In the present study, soil samples of Seyhan Dam Lake Terraces were collected and then pure quartz samples were separated using various separation methods. The quartz samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDX) methods. Thermoluminescence (TL) measurements were carried out using lexsyg smart TL – optically stimulated luminescence (OSL) reader with a constant heating rate of 1 °C/s from room temperature to 450 °C. Beta dose response of the samples were investigated in the dose range from 1 to 10 Gy and the linear dose response range was determined as 1–5 Gy. Computerized glow curve deconvolution (CGCD), peak shape, and isothermal decay (ID) methods were used to determine activation energy (E), order of kinetics (b), and frequency factor (s) of the samples. Furthermore, in this study, minimum detectable dose values of the quartz samples were also determined.

Synthesis and Thermoluminescence of a Spinel-Type Oxide Exposed to Beta-Particle Irradiation

ABSTRACTCurrently, the research team is systematically studying the oxide compounds present in the ternary system In2O3-TiO2-MgO in order to analyze its thermoluminescent (TL) response. The oxide Mg1.5InTi0.5O4 present in this system was synthesized by a solid state reaction at 1350 °C in air. The X-ray powder diffraction pattern showed a spinel-type structure for this compound. In this work, this spinel, as well as its TL properties when exposed to beta particles, are being reported for the first time. The glow curve is simple and wide with a TL maximum located at 203 °C at 21.33 Gy. The peak shows a shift to lower temperatures and it increases its intensity, as the irradiation dose increases. The lineal behavior was observed between 10.66 to 341 Gy, and no saturation signs were observed. The relative sensitivity variation was 2.7% and standard deviation after ten consecutive irradiation - TL readout cycles was 1 %. The minimum detectable dose was 5.65 Gy for this spinel-type oxide [3]. These results suggest the possible application of Mg1.5InTi0.5O4 in dosimetry.

Thermally assisted OSL: A potent tool for improvement in minimum detectable dose and extension of dose range of Al2O3:C

The influence of electron-phonon interaction on the shape of the optically stimulated luminescence decay curve of Al2O3:C has been studied using thermally assisted optically stimulated luminescence (TA-OSL). The minimum detectable dose (MDD) of a phosphor depends on the standard deviation of the background signal which affects the signal-to-noise ratio. The standard deviation of the background signal reduces at lower stimulation light intensity while the readout time increases. Further, measurement at higher temperature enhances the OSL signal with faster decay due to the temperature dependence of photo-ionization cross-section. To achieve the same decay constant and more signal, the temperature of measurement was raised. As a result of lowering the stimulation in-tensity at higher temperature (85°C) the overall MDD of α-Al2O3:C was found to improve by 1.8 times. For extension of dose linearity in higher range, deeper traps were studied by simultaneous application of CW-OSL and thermal stimulation up to 400°C, using a linear heating rate of 4K/s. By using this method, two well defined peaks at 121°C and 232°C were observed. These TA-OSL peaks have been correlated with two deeper defects which can be thermally bleached at 650°C and 900°C respectively. These deeper defects are stable up to 500°C, so they can store absorbed dose information even if the sample is inadvertently exposed to light or heat. The dose vs. TA-OSL response from deep traps of α-Al2O3:C was found to be linear up to 10 kGy, thus extending its application for high dose dosimetry.