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This study examines the thermoluminescent emission of quartz whose existence can be registered with 1 mGy test-doses. Samples originated from three crystals were sensitized using the combined effect of gamma radiation and heat-treatments. The glow curves were registered under five optical setups to collect emissions from ultraviolet to yellow-orange bands. The emissions were scrutinized using a computerized deconvolution method. After sensitization, the activation energies of trapping states increased, and the violet/blue emissions exceeded the near-ultraviolet emission in the whole glow curve. The possibility to remove and restore the sensitization effect and the existence of strong emissions above 350 °C indicates that the rise in TL sensitivity occurs when competition between active and deep traps is annihilated. The narrow distribution of activation energies and the subtle changes in band emissions suggest that TL production in quartz consist of localized transitions involving different energetic levels of the same traps and recombination centers.

Optically Stimulated Luminescence (OSL) is the luminescence emitted from a previously irradiated with ionizing radiation material by exposure to light. The aim of this paper is to evaluate the Blue Stimulation Luminescence (BSL) and Infra-Red Stimulation Luminescence (IRSL) for CaF2:Ce produced by the Solution Combustion Synthesis (SCS) method. The results showed that the OSL response of CaF2:Ce is strongly influenced by post-combustion thermal sintering temperature and dopant concentration. OSL response to dose are of the same order of magnitude of Al2O3:C, indicating the possibility of use of this material for radiation dosimetry.

Nanocrystalline powder samples of barium sulfate doped with Europium (BaSO4:Eu2+) were prepared, at a dopant concentration of 0.02 mol%, by the combustion solid-state technique in air atmospheres. Thermoluminescence (TL) response and dosimetric studies have been carried out for this phosphor in order to characterize it as a radiation dosimeter. The results showed that the TL glow curve of BaSO4:Eu2+present an intense TL peak at 200 °C accompanied by a small shoulder peak at 270 °C. The TL low detection limit for BaSO4:Eu (0.02 mol%) was found to be 17.8 μ G y for the gamma radiation emitted by 137Cs . The comparative study with the LiF:Mg, Ti (TLD-100) and calcium fluoride doped with thulium CaF2:Tm dosimeters showed that the TL response of the BaSO4:Eu(0.02 mol%) synthesized by the combustion solid-state technique is highly sensitive: it is 5.8 times higher than the response of the CaF2:Tm pellets and 9.4 times higher than the response of TLD-100. The high sensitivity of BaSO4:Eu and its linear dose response indicate that it can be used as sensor for gamma ionizing radiations.

The response of thin diodes (SFH206k) as dosimeters has been investigated employing the beam of an electron accelerator within the dose rate range of 2–8 kGy/s and accumulated doses up to 100 kGy. These devices, operating in the short-circuit mode and under industrial irradiation conditions, deliver current signals nonlinearly dependent on the dose rate, whichever the dose history of the diodes, due to the high density of the generated electron-hole pairs herein achieved. Despite this nonlinearity, the dose rate response is stable and characterized by current signals with repeatability better than 2.0%, regardless of the accumulated dose. It is also found that the dose responses are quite linear with sensitivities slightly dependent on the accumulated dose at a constant dose rate. The decrease in the charge sensitivity, taking as reference that obtained before any radiation damage, reaches only 9% (k = 2) at 100 kGy, which is much smaller than the values reported in the literature. From this low aging and the repeatability of both dose rate and dose responses, it seems that the photodiode under investigation is a low budget alternative, good enough for routine dosimetry, provided it has been previously calibrated in the same processing facility.

Calcium Fluoride is one of the oldest known thermoluminescent materials and is considered to be one of the most sensitive. This work presents the dosimetric properties results of CaF2:Tm produced by combustion synthesis. The X-ray diffraction confirmed that CaF2 was successfully produced. TL emission spectra, obtained using a Hammamatsu optical spectrometer, have the same lines of commercial CaF2:Tm, although transitions 3P0→3F4 (455 nm) and 1G4→3H6 (482 nm) are shown to be proportionally more intense. The deconvolution technique was employed and seven glow peaks were found similar to the commercial CaF2:Tm. A linear dose response curve was obtained for the range 0.1 mGy to 100 Gy, with the onset of a supralinear behavior at 50 Gy up to 100 Gy. The minimum measurable dose for gamma was around 100 μGy for a 6.0 mm diameter by 1.0 mm in thickness pellet. No significant fading was observed in 60 days of storage, within experimental uncertainties, showing that the main dosimetric peak is stable.

This work presents the results on the Blue Stimulation Luminescence (BSL) and Infra-Red Stimulation Luminescence (IRSL) of CaF2:Tm produced by the Solution Combustion Synthesis (SCS) method. XRD confirmed the formation of calcium fluoride. BSL showed a dose independent signal due to excitation-emission of Tm bands which was not observed for IRSL. A linear dose response curves was obtained for both Blue-OSL and IR-OSL. IRSL was found approximately three times higher sensitivity than Blue-OSL. The minimum measurable dose (MMD) for BSL was found to be around 1.0 mGy. For IRSL a MMD of around 100 μGy was obtained. The results demonstrated that CaF2:Tm produced by SCS has a strong potential for OSL dosimetry.

The thermoluminescence (TL) and infrared stimulated luminescence (IRSL) responses of in-house produced CaF2:Tm dosimeters are investigated in this work, envisaging their application in electron beam (EB) radiation processing. The irradiations were performed at an industrial EB accelerator (1.5 MeV) covering a dose rate range of 2–8 kGy/s and dose up to 10 kGy. In general, the TL glow curves display four peaks, termed as peaks 2, 3, 4, and 5, corresponding to temperatures at ~150, 200, 240, and 300 °C, respectively. The intensity of the low-temperature peaks (2 and 3) grows with the dose, while the others remain constant (saturated). Nevertheless, an evident dose effect on the glow curves manifests in decreased peak3/peak2 ratio with increasing doses. The CW-IRSL curves exhibit similar patterns with an initial signal increase, followed by an exponential decay. Instead of the normal monotonic decays, these peak-shaped curves might be due to the charge capture competition between empty shallow traps and recombination centers. Both TL and IRSL intensities increase linearly with doses up to 6 kGy, and for higher doses, they become sub-linear with a saturation trend around 10 kGy. Another common feature of TL/IRSL response is its dose rate dependence, being more sensitive at higher dose rates. Despite being dose-rate dependent, the CaF2:Tm dosimeters might be suitable for EB processing dosimetry. However, for their use as routine dosimeters, relevant dosimetric characteristics, such as fading and response reproducibility, have to be investigated. Work in this direction is underway.

The aim of this paper is to characterize the IRSL response of rare earth doped CaF2 and co-doped with Al or Li, produced by the solution combustion synthesis (SCS). The results showed a high intensity of the infrared optically stimulated luminescence (IRSL) response for the samples of CaF2 doped with Tb and co-doped with Li. For the samples of CaF2 doped with Ce and co-doped with Li present better IRSL response than the samples co-doped with Al. It was also observed that the samples of CaF2:Ce,Li present a high fading with 50% reduction of the IRSL signal in a period of 60 min. In case of the CaF2:Tb,Li there is no significant fading during this period. For clinical dosimetry the fast fading of the dosimeter is not adequate. However, this feature can be exploited for other applications such as tamper-proof passive systems that detect and timestamp the movement of undeclared nuclear materials, by the estimation of the OSL response of materials with different fading rates.

The purpose of this paper is to evaluate the use of alanine-EPR as a transfer standard dosimetry system for low energy X radiation, such as that in RS-2400, which operates in the range from 25 to 150 kV and 2 to 45 mA. Two types of alanine dosimeters were investigated. One is a commercial alanine pellets from Aerial-Centre de Ressources Technologiques, France and one was prepared in our laboratory (LMRI-DEN/UFPE). The EPR spectra of the irradiated dosimeters were recorded in the Nuclear Energy Department of UFPE, using a Bruker EMX10 EPR spectrometer operating in the X-band. The alanine-EPR dosimetry system was calibrated in the range of 20–220 Gy in this X-ray field, against an ionization chamber calibrated at the relevant X-ray energy with traceability to PTB. The results showed that both alanine dosimeters presented a linear dose response the same sensitivity, when the EPR signal was normalized to alanine mass. The total uncertainty in the measured dose was estimated to be about 3%. The results indicate that it is possible to use the alanine-EPR dosimetry system for validation of a low-energy X ray irradiator, such as RS-2400.

Doped Calcium fluoride (CaF2) is a well known dosimetric material used for measurement of ionizing radiation. In the literature we can find several synthetic routes to prepare this materials, however the majority of the methods present disadvantages such as long time for preparation, use of hazardous materials or crystal growth infrastructure. In order to overcome these problems, in this paper we present a simple wet chemical process by which calcium fluoride doped with thulium was fabricated. The crystal structure and particle size of the synthesized material was characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The thermoluminesce response for samples irradiated with 60Co gamma radiation showed a linear response up to 10 kGy. Additionally, the TL emission spectra shows spectroscopic emission lines characteristic of Tm3+, where the relative intensity of each line depend on the fabrication parameters.

The 110 °C TL glow peak of quartz has been used in dating and retrospective dosimetry due to the pre-dose effect and the sensitivity changes caused by heating. One of the main difficulties related to TL dating is the sureness that the geological signal was completely zeroed by firing. In this study, the sensitivity change of the 110 °C peak and the EPR signal intensity of the E 1 ′ center were combined to account for the burning status of archaeological pebbles. For this, a quartz pebble was sawn into many pieces and each piece was heat-treated at different temperatures from 200 to 800 °C. Powdered aliquots were γ-irradiated and stored into an ice-bath before the TL readout. Peak-maximum temperature, TL intensity and activation energy of the 110 °C peak were determined by glow curve deconvolution methods. The thermal activation characteristic obtained in this study showed a peak maximum at 500 °C and a sensitization ratio higher than 200. The heating temperature also affected the intensity of the E 1 ′ center. The usefulness of the burning pattern was tested by measuring the TL and EPR signals of several archaeological pebbles, initially classified as “burnt”, “unburnt” or “unidentified”, and also from two specimens burnt in a campfire. The main achievement of this study was the possibility to infer the temperature in which a pebble was heated in the past independent of visual signs.

This study evaluates the dose received by veterinarians and assistants involved in portable digital veterinary radiology procedures and checks the dose reduction obtained with the use of individual protection equipment. For this evaluation measurements were made using thermoluminescent dosimeters TLD-100, positioned at different parts of the body: hands, thorax, thyroids, gonads, left and right eye corners and at the center of the eyes. The dose was evaluated through 65 procedures performed with 55 animals. The results showed that in the case of assistants the received dose is significantly larger than that of the veterinarian. The most likely reason of this effect is that they are closer to the primary beam and thus are exposed to higher level of primary radiation first of all in regions of eyes and thyroids. The doses received by various body parts of the assistant are close to the annual limit recommended by International Commission on Radiological Protection.

The purpose of this paper is to characterize the tiles placed on the walls of the Franciscan convent of "Santo Antônio" (Recife-PE) and to obtain information about the several expansions and structural reforms performed on the convent by dating the bricks. For this purpose, a portable energy dispersive x-ray fluorescence (EDXRF) was used to characterize the tiles. The dating of the bricks was performed using the Thermoluminescence (TL) technique. The results of the EDXRF analysis show that the dominant component of the white pigment is lead [2PbCO(3)·Pb(OH)(2)], used since the ancient times until the 20th century, while the dominant element of the blue pigment is cobalt (CoO·Al(2)O(3)), that has been used from 1807 until nowadays. The TL dating of bricks indicate that there were walls with different periods of construction, being one built around 1765, with a deviation of 28 years, whereas other was built later, around 1874, with a deviation of 15 years. These results provide new data towards understanding how and when the Recife Franciscan convent of "Santo Antônio" was designed and built, contributing to other research works presently underway on site.

The aim of this paper is to evaluate the thermoluminescent (TL) response of a larimar, a variety of pectolite (NaCa 2 Si 3 O 8 [OH]). It is a blue pectolite only found on the terrestrial crust of the province of Barahona, in the south-western region of the Dominican Republic. The larimar rock used in this study, presented a light-blue color with brown areas. X-ray powder diffractometry (XRD), showed that the light-blue portion of the rock is composed essentially by pectolite and the brown portion is composed by a mixture of minerals. Aliquots of 5 mg of light-blue portions were irradiated with gamma rays with doses from 10 to 10 4 Gy and the TL glow curves were obtained from 50 to 400 °C. The glow curve showed a broad peak around 150 °C and a peak near 280 °C. Different pre-heat condition were used to remove the broad peak. The TL emission of the main peak appeared in the region of 580 nm. The TL response of the main peak showed a linear behavior up to 2500 Gy and a sub-linear behavior above this dose value. Studies of the 30 day fading effects in TL signal using a pre-heating temperature around 180 °C during 15 min were carried out and fading near 25% was observed.

In this paper, we describe the results obtained for the evaluation of a multi-guard ring (MGR) structure diode as diagnostic X-ray dosimeter. This device was developed in the framework of R&D programs for the future CMS experiment at the Large Hadron Collider (LHC) with high radiation hardness to fulfill the requirements from this accelerator environment. In order to use the MGR diode as a dosimeter, it was connected in the photovoltaic mode to the input of an integrating electrometer and positioned at the center of an X-ray beam, beside a previously calibrated ionization chamber. The dependence of the diode response on the X-ray beam doses was evaluated for 35–90 kV X-ray generator bias supply, with doses in the range of 50 μGy–5 mGy. The good linearity of the dose–response curve obtained showed the MGR diode dosimeter to be a reliable alternative method for diagnostic X-ray dosimetry.