Thermoluminescence dosimeter (TLD) studies of Ca10 K(PO4 )7 :Dy phosphor for applications in radiation dosimetry.

This study reports the thermoluminescence (TL) aspects of Ca10 K(PO4 )7 :Dy phosphor synthesized using a wet chemical method for the first time. The X-ray diffraction (XRD) results confirm the formation of the desired crystalline phase. Surface morphological studies reveal the formation of polyhedrons and agglomerations having an average diameter of 200 nm, while energy dispersive X-ray spectroscopy (EDS) data show the presence and composition of the elements in appropriate amounts. The effect of Dy doping concentration has been studied on the TL properties with exposure to gamma radiations from the Co-60 source. The best TL response has been observed for 5 mol% Dy doping concentration. The glow curve is simple and consists of a single peak at 130°C. The effect of the heating rate has been studied on the TL glow curve, and the heating rate of 5°C/s shows the best TL response. The various TL properties such as annealing conditions, dose-response, TL linearity, fading, and reusability of the prepared phosphor have been studied to check its suitability as a good TL dosimeter (TLD). TL characterization of the phosphor reports that the TL response is linear from 5- to 2000 Gy. The results show that this phosphor can be a good TLD for the dosimetry of gamma radiations from Co-60.

Thermoluminescence studies of zinc borate (ZnB2 O4 ) phosphor doped with rare earths for dosimetric aspects.

A series of ZnB2 O4 phosphors doped with different concentrations of Eu and Dy (0.05 0.1, 0.2, 0.5, 1.0 mol%) and co-doped with Ce (1, 2, 5, 7, 10 mol%) respectively was prepared via the solid-state reaction technique and the thermoluminescence (TL) behaviour of gamma ray-irradiated samples was studied. The synthesized samples were irradiated with γ-rays for the dose range 0.03-1.20 kGy. The TL intensity variations with dose, dopant concentration, and the effect of co-doping were studied. The TL response curves for ZnB2 O4 :Eu3+ and ZnB2 O4 :Dy3+ , ZnB2 O4 :Eu3 ,Ce3+ and ZnB2 O4 :Dy3+ ,Ce3+ phosphor were observed. It was revealed that ZnB2 O4 :Eu3+ showed a linear TL behaviour for the dose 0.03-1.20 kGy and ZnB2 O4 :Dy3+ showed linearity for the gamma dose range 0.03-0.10 kGy. Furthermore, fading for all the samples was observed to be less than 10% for a storage period of 30 days. In addition to this, the trapping parameters, especially activation energies were evaluated using the Ilich method and the initial rise method. The activation energy values obtained from both methods were in complete agreement with each other.

Response of TLD-600/TLD-700 and CR-39 to neutrons for medical dosimetry.

In this study, thermoluminescence detectors (TLD)-600 and TLD-700 were used under different conditions to study neutron dosimetry for its application in medical dosimetry as albedo dosimeters. 6 LiF has a high cross-section for neutrons and is more sensitive to neutrons than to gamma radiation. Conversely, TLD-700 showed a better response to gamma radiation. Therefore, to obtain the response for neutrons, the responses for TLD-600 and TLD-700 were subtracted. A cadmium sheet was used to absorb incident thermal neutrons so that detector measured only backscattered neutrons from the albedo dosimeter. A Perspex sheet was used as a moderator to thermalize the fast neutron source Am-Be used in the experiment. CR-39 was used to detect fast neutrons and act as an albedo dosimeter when covered with a 10 B disc. Both TLD and CR-39 dosimeters were successful in detecting scattered neutrons in radiotherapy rooms.

Recent developments in phosphate materials for their thermoluminescence dosimeter (TLD) applications.

The use of phosphate-based thermoluminescence dosimeter (TLD) materials in current scenarios is presented here, particularly for the field of low dosimetry. TLD materials are currently researched for their use in for example environmental dosimetry, personal dosimetry, and medical dosimetry. There are several TLD materials available such as: sulphates, borates, fluorides, and sulphides, including some metal oxides and perovskites, which are the most used and have been widely explored. In the present scenario, new interest is being focused on the need for thermoluminescent materials for application in material science and radiation dosimetry for low-dose dosimetry. These doped TLDs are prepared using different techniques including solid-state reaction methods, combustion methods, wet chemical methods, and sol gel methods. Therefore, among the above stated TLDs, phosphates have opened a new door in radiation dosimetry, particularly in low-dose dosimetry over the last few years. This paper mainly deals with a review of various phosphate-based TLD materials and recent advancements in phosphates for TL dosimetry.

Luminescence study of LiMgBO3 :Dy for γ-ray and carbon ion beam exposure.

LiMgBO3 :Dy3+ , a low Zeff material was prepared using the solution combustion method and its luminescence properties were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermoluminescence (TL), photoluminescence (PL), Fourier transform infrared spectroscopy, and electron paramagnetic resonance (EPR) techniques. Reitvield refinement was also performed for the structural studies. The PL emission spectra for LiMgBO3 :Dy3+ consisted of two peaks at 478 due to the 4 F9/2 →6 H15/2 magnetic dipole transition and at 572 nm due to the hypersensitive 4 F9/2 →6 H13/2 electric dipole transition of Dy3+ , respectively. A TL study was carried out for both the γ-ray-irradiated sample and the C5+ irradiated samples and was found to show high sensitivity for both. Moreover the γ-ray-irradiated LiMgBO3 :Dy3+ sample showed linearity in the dose range 10 Gy to 1 kGy and C5+ -irradiated samples show linearity in the fluence range 2 × 1010 to 1 × 1011 ions/cm2 . In the present study, the initial rise method, various heating rate method, the whole glow curve method, glow curve convolution deconvolution function, and Chen's peak shape method were used to calculate kinetic parameters to understand the TL glow curve mechanism in detail. Finally, an EPR study was performed to examine the radicals responsible for the TL process.

Versatility of thermoluminescence materials and radiation dosimetry - A review.

Thermoluminescence (TL) materials exhibit a wide range of applications in different areas such as personal dosimetry, environmental dosimetry, medical research etc. Doping of different rare earth impurities in different hosts is responsible for changing the properties of materials useful for various applications in different fields. These materials can be irradiated by different types of beams such as γ-rays, X-rays, electrons, neutrons etc. Various radiation regimes, as well as their dose-response range, play an important role in thermoluminescence dosimetry. Several TL materials, such as glass, microcrystalline, nanostructured inorganic materials and recently developed materials, are reviewed and described in this article.