Organ dose coefficients for Asian-scaled computational phantoms resulting from external exposures at the Techa River due to ground contamination

Date(s) - 07/03/2014
10:00 am

Bryan Schwarz, MS student

Estimates of organ dose from external exposures in the Techa River Dosimetry System are based upon air kerma rates at the river shoreline and residential areas (calculated from modeled concentrations of radionuclides from 1950-1951 and measured and/or interpolated values since 1952) and values of external dose conversion factors reported in EPA Federal Guidance Report No. 12 (FGR 12) from the Oak Ridge National Laboratory. In FGR 12, adult hermaphrodite stylized phantoms were used to provide organ dose coefficients for uniform concentrations, semi-infinite or infinite sources of monoenergetic photons and electrons in both the air and the ground. These dose coefficients are then spectrum weighted to yield organ dose coefficients for specific radionuclides.The objective of this research is to update the organ dose coefficients used in the Techa River Dosimetry System dose reconstruction efforts with Techa River specific organ dose coefficients. New gender and age specific adult and pediatric phantoms from the UF/NCI family of hybrid phantoms are being utilized in this study. The phantoms have been matched to standing height, sitting height, and total body weight given in IAEA Technical Document 1005 on the Asian Reference Man. Chest circumferences are scaled to anthropometric data listed in that same document. Soil concentrations and densities specific to the Upper and Middle/Lower Techa River are employed in Monte Carlo simulations to generate organ dose coefficients. FGR 12 soil is also utilized in the Monte Carlo simulations as reference soil to allow for quantitative comparisons to values given in FGR 12.