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 Zeff of these numerous tiles' samples (11.6-12.7) with TLD-200 (Zeff = 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.

Sub kGy photon irradiation alterations in graphite.

Present work concerns polymer pencil-lead graphite (PPLG) and the potential use of these in elucidating irradiation-driven structural alterations. The study provides detailed analysis of radiation-induced structural interaction changes and the associated luminescence that originates from the energy absorption. Thermally stimulated emission from the different occupied defect energy levels reflects the received radiation dose, different for the different diameter PPLGs. The PPLG samples have been exposed to photon irradiation, specifically x-ray doses ranging from 1 to 10 Gy, extended to 30-200 Gy through use of a60Co gamma-ray source. Trapping parameters such as order of kinetics, activation energy and frequency factor are estimated using Chen's peak-shape method for a fixed-dose of 30 Gy. X-ray diffractometry was used to characterize the crystal structure of the PPLG, the aim being to identify the degree of structural order, atomic spacing and lattice constants of the various irradiated PPLG samples. The mean atomic spacing and degree of structural order for the different diameter PPLG are found to be 0.3332 nm and 26.6° respectively. Photoluminescence spectra from PPLG arising from diode laser excitation at 532 nm consist of two adjacent peaks, 602 nm (absorption) and 1074 nm (emission), with mean energy band gap values within the range 1.113-1.133 eV.