An estimate of the propagated uncertainty for a dosemeter algorithm used for personnel monitoring

Abstract

The Y-12 National Security Complex utilises thermoluminescent dosemeters (TLDs) to monitor personnel for external radiation doses. The TLD consist of four elements positioned behind various filters, and dosemeters are processed on site and input into an algorithm to determine worker dose. When processing dosemeters and determining the dose equivalent to the worker, a number of steps are involved, including TLD reader calibration, TLD element calibration, corrections for fade and background, and inherent sensitivities of the dosemeter algorithm. In order to better understand the total uncertainty in calculated doses, a series of calculations were performed using certain assumptions and measurement data. Individual contributions to the uncertainty were propagated through the process, including final dose calculations for a number of representative source types. Although the uncertainty in a worker's calculated dose is not formally reported, these calculations can be used to verify the adequacy of a facility's dosimetry process.