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Thermoluminescence and phototransferred thermoluminescence measurements of protective glass from smartphones are described. Samples of Gorilla Glass were examined from nine different manufacturers and 40 different phone models. Additionally, 12 glasses believed to be original equipment manufacturer replacements, as well as three glass samples from U.S. finishers, were also studied. Altogether, 99 different Gorilla Glass samples were examined. The radiation-induced thermoluminescence signal produced glow curve shapes specific to the Gorilla Glass generations and could be used to distinguish between them. A background thermoluminescence (and phototransferred thermoluminescence) signal was found in all unirradiated samples. Its intensity and shape were found to be dependent on the Gorilla Glass generation, phone manufacturer, and phone model. The background signal was demonstrated to be produced by ultraviolet light exposure; the shape of the background signal was able to be reproduced by the combined exposure to a broad-spectrum solar simulator and a 302 nm ultraviolet light source. The background signal intensity was found to vary with the location from which it was taken on the glass. It was also found to be dependent on the depth within the Gorilla Glass due to absorption of the ultraviolet light as it traversed the medium. Removal of the glasses' surface layers was found to be an inadequate method for removing the background signal. In some samples, the background signal intensity was large enough to significantly contribute to the total thermoluminescence (and phototransferred thermoluminescence) signal; therefore, a matrix deconvolution method was introduced to separate the background signal and radiation-induced signal. This method was found to enable dose reconstruction using the radiation-induced signal alone. [ABSTRACT FROM AUTHOR]

A measurement technique is introduced which involves linearly modulating the power of the stimulation light while measuring the photoconductivity in Al[sub 2]O[sub 3]:C. This produces peaks in the measured photoconductivity instead of the typical exponential decay seen when using a constant power stimulation light. The technique, called linearly modulated photoconductivity (LM-PC), is the conductivity equivalent of linearly modulated optically stimulated luminescence (LM-OSL). Two peaks are seen in the LM-PC measurements that correspond to the same charge residing in the 450 and 600 K thermally stimulated conductivity peaks, respectively. Simultaneous measurements on both the LM-PC and LM-OSL reveal that the second peak in the LM-PC is not present in the LM-OSL. Deconvolutions are performed on the LM-OSL to determine the underlying components that make up the detected OSL emissions. [ABSTRACT FROM AUTHOR]

The laboratory of Microbiology at SCK•CEN, in collaboration with different universities, participates in several ESA programmes with bacterial experiments that are carried out in the International Space Station (ISS). The main objective of these programmes is to study the effects of space flight conditions such as microgravity and cosmic radiation on the general behaviour of model bacteria. To measure the radiation doses received by the bacteria, different detectors accompanied the microbiological experiments. The results obtained during two space flight missions are discussed. This dosimetry experiment was a collaboration between different institutes so that the doses could be estimated by different techniques. For measurement of the high linear energy transfer (LET) doses (>10 keV µm-1), two types of etched track detectors were used. The low LET part of the spectrum was measured by three types of thermoluminescent detectors (7LiF:Mg,Ti; 7LiF:Mg,Cu,P; Al2O3:C) and by the optically stimulated luminescence technique using Al2O3:C detectors. [ABSTRACT FROM AUTHOR]

This paper presents two different approaches of quantifying the optically stimulated luminescence (OSL) response of Al2O3:C to high-energy heavy charged particles (HCPs). The OSL efficiency of Al2O3:C exposed to different HCPs is defined as the sensitivity of the material to HCPs normalised by the sensitivity to gamma. In this paper, we investigate the possibility of introducing a 'mean efficiency' ηmean, which when used in conjunction with the total gamma dose Dγ measured for a mixed radiation exposure allows for the determination of the absorbed dose without the need to determine the individual contributions of different types of radiation to the OSL signal. We tested the hypothesis that information regarding the 'mean efficiency' ηmean is contained in the shape of the OSL decay curve, using several approaches in the analysis of the OSL data. This analysis was applied to various mixed field irradiations performed at the HIMAC facility, Chiba, Japan. The results of this analysis are discussed. [ABSTRACT FROM AUTHOR]

Three different methods for characterising the dose deposition profile of a 90Sr/90Y radioactive source are described: GAFChromic film dosimetry, Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL). For the film measurements, GAFChromic film samples were stacked at different depths between polyethylene terephthalate (PET) foils. For TL, the thickness of a TLD-500 dosemeter was gradually reduced by polishing and the TL from chips of different thickness was used in conjunction with a mathematical model based on the exponential attenuation of dose inside the crystal to determine the decay constant for the dose-depth profile. Finally, an OSL reader with confocal stimulation / detection capabilities was used to map the two-dimensional dose distribution in TLD-500 dosemeters as a function of depth. The shapes of the dose deposition profiles obtained from all the investigated methods are in good agreement. [ABSTRACT FROM AUTHOR]

Low temperature radioluminescence spectra of LiF, variously co-doped with Mg, Cu and P, show highly unusual temperature dependencies which resemble thermoluminescence data. The signals include intense peaks and a relatively weak continuous background. One peak occurs below 30 K, together with a major peak near 125 K. The signals are highly sensitive to the dopants and slightly sensitive to X-ray dose rate. The role of donor acceptor pairs and the perturbations from intrinsic defects formed by ionisation can be used to describe all the observations. The 290 nm emission band is linked to H center annealing. [ABSTRACT FROM AUTHOR]