The Potential Use of Car Windscreens for Post-Accident Dose Reconstruction in the Periphery of Nuclear Installations

Exploring the thermoluminescence characteristics of smartphone screen safety glasses for retrospective dosimetry applications

In clinical settings, standard dosimeters might miss radiation mishaps. Retrospective dosimeters could help to track personnel (such as patients and other staff who don't wear dosimeters) exceeding safe limits and assess long-term exposure trends. This study has investigated key thermoluminescence (TL) dosimetric characteristics, including the glow curve structure, dose-response, energy dependence, sensitivity and fading of various safety glasses that are used as screen protectors of smartphones subjected to photon irradiation. Among the studied glasses, the HD Anti-Peep safety glass for iPhone has been found to exhibit a linear dose-response with a regression coefficient of 99% within the dose range of 2-10 Gy. Moreover, all the safety glasses showed independence with respect to photon energy of 6 MV and 10 MV. The TL glow curves of the samples showed a broad glow peak between 125 °C and 325 °C at 10 Gy. The TL kinetic parameters of the safety glasses were also studied by analyzing the glow curves using the peak shape and initial rise method. The geometric factor (μg) is found to be within the range of 0.43-0.53, which indicates the suitability of applying Chen's general-order formula to calculate the kinetic parameters such as activation energy, frequency factor and trap lifetime. The activation energy (E) and frequency factor (s) are found in the range of 0.31-0.54 eV and 4.55 × 103 to 2.12 × 106 s-1 respectively obtained via the peak shape method. The relatively long trap lifetime and observed thermoluminescence features indicate that the HD Anti-Peep safety glass offers a better option to estimate dose retrospectively to ensure the safety of human health.

Zinc-Doped Magnesium Borate Glass: A Potential Thermoluminescence Dosimeter for Extended Range of Dosimetric Applications

In this study, we report the dosimetric properties of zinc-doped magnesium borate (MgB4O7:Zn) glass, which was originally synthesized. MgB4O7:Zn glass was successfully synthesized through the melt-quenching technique. The amorphous nature of the synthesized samples was observed through X-ray diffraction (XRD) analysis and further confirmed through field emission scanning electron microscopy (FESEM) analysis. The glass-forming ability and thermal stability were estimated to be 0.61 and 1.62, respectively. The TL dosimetric characteristics, i.e., dose response, reproducibility, TL sensitivity, minimum detectable dose and signal stability, are reported. The synthesized sample demonstrated a simple glow curve with a single well-defined dosimetric peak at 240 °C with an optimal heating rate of 7 °C s−1. The synthesized glass demonstrated a linear dose response from 3 Gy to 5 kGy. The promising dosimetric characteristics demonstrate the potential of the synthesized glass to be recommended as a TL dosimeter for a wide range of applications.

The effectiveness of ornamental building materials (tiles) for retrospective thermoluminescence dosimetry

Like many other decorative building materials, tiles are one of the most precious ornamental ingredients for making a lucrative building image. It not only offers beauty and luxury but also added value by protecting/monitoring ionizing radiation. In this study, the utmost regular use of seven varieties of tile samples has been considered for retrospective thermoluminescence dosimetry. To observe the potentials of tiles for retrospective dosimetry, the major thermoluminescence properties (such as dose-response, energy dependence, self-sensitivity, relative sensitivity, glow curves, repeatability, fading, and also effective atomic number) has been investigated following the annealing - irradiation - readout cycles. Making an allowance for the various TL parameters, White Horse (Mirror Polish) tiles demonstrate suitability to be used as emergency TL dosimeter in 0.5-100 Gy dose array. Comparing the values of Z_eff of these numerous tiles' samples (11.6-12.7) with TLD-200 (Z_eff = 16.3), it is to be noted that tiles can be used as a suitable material for environmental radiation dosimetry. The thermoluminescent characteristics of tiles in the dose limit from 0.5 Gy to 100 Gy are reported here for the first time.

Thermoluminescence Dosimetric Attributes of Yb3+ Doped BaO-ZnO-LiF-B2 O3 Glass Material After Er3+ Co-doping

Motivated by our previous study on Sm³⁺ ions as thermoluminescence (TL) sensitizers to the BaO-ZnO-LiF-B₂ O₃ -Yb₂ O₃ glass system, in current study we examine the effect of Er³⁺ ion co-doping on the TL characteristics of this glass system. The 4f-4f electronic transitions of the Er³⁺ and Yb³⁺ ions were confirmed via the optical absorption spectrum. Notably, the use of Yb³⁺ -Er³⁺ ions failed to improve the TL intensity, sensitivity, and trap density. However, they enabled the glass system to function as an activator-quencher system. The linearity range and effective atomic number remained unaffected after co-doping. In addition, the problem of anomalous fading caused a remnant signal of just 58% after a week of storage of the Yb³⁺ mono-doped glass. This was resolved by the optimum co-doping of Er³⁺ ions to achieve an 89% signal. The co-doping of Er³⁺ ions to the BaO-ZnO-LiF-B₂ O₃ -Yb₂ O₃ glass system regulated its thermal stability and therefore supplemented its potential for radiation monitoring in food processing and retrospective dosimetry.

The potential of decorative building materials (marble) for retrospective thermoluminescence dosimetry

Among the various types of decorative materials used in Bangladeshi dwellings, the marble/marble stone is one of the most common ones that used largely for enhancing the beauty and/or aristocracy of the dwelling environment. In this study, the most commonly used, six types of marble stones, have been analyzed for retrospective accident dosimetry. With the interest of characterizing several key thermoluminescence properties to examine their potentiality for dosimetry, annealing - irradiation - readout steps have been done chronologically which comprises the analysis of glow curves, relative sensitivity, dose dependence, repeatability and fading. Considering the various TL parameters, marble 'Carrara' imported from Italy present relatively better capability for reconstruction of radiation dose in the dose range of 10-50 Gy. From fading result, it is clear that for reconstruction of absorbed dose up to four weeks of post exposure, the marble 'Carrara' is found to be the most reliable media among the studied marble types. The Z_eff values for the various marble samples are found to be in the range of 13.65-19.12, comparing favorably in replace of TLD-200 (Z_eff = 16.3) which can be used for low-level environmental radiation dosimetry. Present work constitutes the first study to investigate the potentials of marble stone for reconstruction of absorbed dose in the range of 10-50 Gy dose.

Photonic crystal fibre as a potential medium for radiotherapy dosimetry

Present study concerns the key thermoluminescence (TL) properties of photonic crystal fibres (PCFs), seeking development of alternatively structured TL materials that are able to offer a advantages over existing passive dosimeters. In terms of their internal structure and light guiding properties the PCFs, collapsed and structured, differ significantly from that of conventional optical fibres. To investigate the dosimetric parameters of the PCFs use was made of a linear accelerator producing a 6 MV photon beam, delivering doses ranging from 0.5 Gy to 8 Gy. The parameters studied included TL response, linearity index, glow curves, relative sensitivity and TL signal fading, the results being compared against those obtained using TLD-100 chips. At 4 Gy photon dose the Ge-doped collapsed PCFs were found to provide a response 27 × that of structured PCF, also giving a TL yield similar to that of standard TLD-100 chips. Over post-irradiation periods of 15 and 30 days collapsed PCF TL signal fading were 8% and 17% respectively, with corresponding values of 37% and 64% for the structured PCF. Trapping parameters including the order of kinetics (b), activation energy (E) and frequency factor (s^-1) were assessed with Chen's peak shape method. Lifetime of trapping centre was found to be (2.36 E+03) s and (9.03 E +01) s regarding the collapsed and structured PCF respectively with 6 Gy of photon beam. For the Ge-doped collapsed PCF, the high TL yield, sensitivity and low fading provide the basis of a highly promising system of TLD for radiotherapy applications.

Studies of thermoluminescence kinetic parameters of polymer pencil lead graphite under photon exposures

This study analysed thermoluminescence (TL) glow curves of the polymer pencil lead graphite (PPLG) due to its potential applications in radiation dosimetry. The TL glow curves provide information on the physical parameters of the defects participating in luminescence process. The glow curves for different diameters PPLG samples were obtained with varying temperature from 50 to 300 °C, at a fixed heating rate of 10 °Cs^-1. A number of methods (initial rise, peak shape and curve fitting) were used to fit the TL glow peaks of the PPLG samples obtained under photon dose of 200 Gy. From the fitted TL signals, the trap parameters such as the order of kinetics, the activation energy, the frequency factor, etc. for the individual peaks were numerically determined. The lifetimes of TL process were calculated assuming the first-order kinetics. The results are compared among the different methods adopted in this study. Implications about the possible results in glow curve deconvolution are discussed.