Teste | Abstract: 142-1 | ||||
Abstract:Retrospective dosimetry is a process to estimate and quantify absorbed doses from radiation fields received by an individual or object in a past event, using physical, chemical, biological, or historical evidence. This field combines direct measurement techniques, such as analysis of bioindicators or materials exposed to radiation, as well as mathematical modeling and historical data, to reconstruct exposure accurately and metrologically reliably. Suitable dosimetric materials for this purpose must not only be readily available in the environment but also possess specific characteristics such as radiation sensitivity, homogeneity, and the ability to store exposed energy from before an accident until subsequent analysis. In the context of retrospective dosimetry, solid-state dosimetry techniques such as thermoluminescence (TL) and optically stimulated luminescence (OSL) have proven to be potentially powerful tools for reconstructing absorbed doses following accidental irradiation. Assessment protocols used in accident dosimetry are based on those developed for dating archaeological and geological samples. In this study, we employed the Single Aliquot Regenerative (SAR) protocol in conjunction with TL and OSL techniques. Motor vehicles are known to be parked at varying distances in fixed locations along traffic routes and nuclear installations. In case of accidents, automotive components can provide an accurate dose mapping (values of varying doses across the accident site). Based on this principle, this study considered automotive spark plugs as materials with significant dosimetric potential for application in retrospective dosimetry due to their luminescent properties. The objective of this work is to investigate the use of automotive ceramic components, specifically spark plugs, for application in retrospective dosimetry using the SAR protocol. Different aliquots of spark plugs from various manufacturers were used for this purpose. The absorbed dose to be reconstructed, along with all regenerative doses and TL and OSL readings, were performed using a RISØ TL/OSL DA-20 reader with an incorporated 90Sr/90Y irradiator. For method evaluation, accidental doses ranging from 300 to 1000 mGy were simulated using a blind irradiation test conducted by an operator not involved in the study. Sample preparation involved removing residual signals present in the samples using TL or OSL techniques, depending on the evaluation method to be employed. Following this step, 15 aliquots were evaluated to measure accident, residual, reference, and regenerative doses, from which glow curves were generated to calibrate and subsequently estimate the average accident dose. Results from SAR protocol utilization showed percentage variations of less than 5% for thermoluminescence technique and less than 1% for OSL technique within the studied range. Keywords: Retrospective dosimetry , Thermoluminescence, Optically stimulated luminescent, Single Rate Protocol (SAR), Ignition candles of cars |