Assessment of Occupational Exposure Dose to Radiation Workers in Secondary Standard Dosimetry Laboratory of Mongolia

Abstract

The most accurate calculation strategies available should be used for the estimation ofradiation doses in the potential accident associated with radioactive sources in laboratories. Theobjective of this study was to estimate skin dose, eye dose and personal dose equivalent to radiationworkers in the Secondary Standards Dosimetry Laboratory (SSDL) in Mongolia which nationwideprovides calibration services for dosimetry instrument and ensures that radiation measurementsare consistent with International System of Units (SI). Using a computer code for skin contaminationdosimetry, VARSKIN, in case of unexpected accidental exposure scenarios, we compared theresults of computer code with the measurements of thermoluminescent dosimeter (TLD). Amongthe most frequently used radionuclides in the laboratory practices, 137Cs radiation source wasselected and analysis of data obtained from TLD was also described in this study. We studied apoint and cylindrical source geometry assuming varying thicknesses of absorbing layers. The computercode was successfully used to calculate directional dose equivalent Hʹ (0.07) in terms of controlof skin dose and area monitoring, personal dose equivalent Hp(10) in terms of effective doseand individual monitoring. Results indicated a good comparison between the calculation resultsand measurement data. The deviations between calculated and measured doses were found to bewithin the range of 2.6% for different time interval measurements. For the skin depth of 0.07 mm,dose rates were 7~12 times higher than the depth of 3 mm and 10 mm for eye and equivalent dose,respectively.