Browsing by Subject "TLD"
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Item External detection and measurement of inhaled radionuclides using thermoluminescent dosimeters(Texas A&M University, 2007-04-25) Prause, Christopher AlvinMany radiation detection programs use bio-assays, whole-body counters, or air sampling to estimate internal doses. This study examines the possibility of using a common external thermoluminescent dosimeter (TLD) badge as a device for detecting inhaled radionuclides through radiation those radionuclides emit which escape the body. The three common radionuclides chosen for modeling due to their varying decay modes and use or production in the nuclear industry were Cs-137, U-238, and Sr-90. These three radionuclides were modeled for biological and radiological removal in the dynamic systems modeling program of STELLA II and modeled for TLD dose per organ in the geometry and radiation simulation program of MCNP. The results show that none of the nuclides in the study can be detected at air concentrations below regulatory limits for acute inhalation exposures. To achieve a detectable dose from an 8-hour work exposure, with a 90-day wait until the TLD is read, the airborne concentrations for the inhalation classes that produced the most dose per Bq would be 37.9 kBq/m3, 146 MBq/m3, and 1.67 MBq/m3 for Cs-137, U-238, and Sr-90, respectively.Item Response comparison of an optically stimulated luminescent dosimeter, a direct-ion storage dosimeter, and a thermoluminescence dosimeter(2009-05-15) Hernandez, Pete JevonThis study was undertaken to compare the response of three dosimeters to different environments. Comanche Peak Nuclear Power Plant wants to replace the current badge of record. The RaDos DIS-1 direct-ion storage dosimeter (DIS-1) and the Landauer InLight optically stimulated luminescence dosimeter (OSL) are the two candidates for replacement of the Panasonic UD-802 thermoluminescence dosimeter (TLD). The dosimeters were compared in five categories: dose linearity, dose-rate linearity, fade response, humidity response, and the angular dependence of the dosimeters. The major results include verified linear relationship evidence for dose and doserate and a better fade response for both the DIS-1 and OSL. The TLDs faded by 9.2% over a month and the DIS-1 and OSL faded by 4.2% and 1%, respectively. Following a dose of 557.5 mrem, the dosimeters were exposed to different relative humidites. The dose to the DIS-1 and OSL did not change drastically while the TLDs dose readout was reduced by 10%. Finally, the angular dependence of the dosimeters was compared and the worst responses were 66% at 90? in the horizontal orientation for the OSL and 1.7% at 90? in the horizontal orientation for the DIS-1. Based on the results of these tests the OSL seems like a more viable candidate for the new badge or record.