Operational Comparison of Bubble Dosimetry with Albedo Thermoluminescent Dosimetry for a Selected Group of 238Pu Workers

Abstract

Personnel neutron dosimetry continues to be a difficult science due to the lack of availability of robust passive dosimeters that exhibit tissue equivalent, or near tissue equivalent response. The dosimeter most used for neutron dosimetry in the United States remains the albedo thermoluminescent dosimeter (TLD). Track-etch and bubble dosimeters generally have a more favorable energy response than albedo dosimeters but are more difficult and expensive to use. This paper is an operational study that compares the use ofalbedo TLDs with bubble dosimeters to determine whether bubble dosimeters do provide a useful daily tool to achieve as low as reasonably achievable (ALARA) goals that can yield measurements close to the dose-of-record from TLD. A group of workers working on the radioisotope thermoelectric generators (RTGs) for the National Aeronautics Space Administration (NASA) Cassini space mission wore both bubble dosimeters and albedo dosimeters over a period from 1993 through 1996. The bubble dosimeters were issued and read on a daily basis and the data were used as an ALARA tool. The personnel albedo dosimeter was processed on a monthly basis and used as the dose-of-record. The results of this study indicated that cumulative bubble dosimetry results agreed with whole-body albedo dosimetry results within about 37%. However, it was observed that there is a significant variability ofthe results on an individual basis both month-to-month and from one individual to another.