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External gamma dose responses from residual radioactive materials in soil

Conference · · Transactions of the American Nuclear Society; (USA)
OSTI ID:5233908

External gamma dose responses from radioactive soils have previously been calculated as air-absorbed doses in a point receptor above the ground. Such responses, however, are not accurate measures for estimating the effective dose equivalent (H{sub E}) for assessing radiological risks to humans, as defined by the International Commission on Radiological Protection (ICRP). The ambient dose equivalent H*(10), as defined by the International Commission on Radiation Units and Measurements (ICRU), is considered to provide a more accurate and yet conservative estimate of H{sub E}. The quantity H*(10) is the dose equivalent obtained at a 10-mm depth of the ICRU spherical phantom with a 30-cm radius, which accounts for attenuation and scattering of radiation in the tissue phantom. According to the ICRP, the ratio between H*(10) and the air-absorbed dose varies from 0.01 to 1.73 for source photon energies from 0.01 to 10 MeV. Such large differences in the two dose quantities are expected to result in substantial deviations in the doses calculated using the two different dose concepts. The primary objective of this study was to calculate dose responses for radioactive soils based on the newer concept of ambient dose equivalent H*(10). This involved improving the past calculations, including the use of more up-to-date photon cross sections for soil and a Monte Carlo calculational procedure specially tailored to provide accurate results for this specific application.

OSTI ID:
5233908
Report Number(s):
CONF-890604--
Journal Information:
Transactions of the American Nuclear Society; (USA), Journal Name: Transactions of the American Nuclear Society; (USA) Vol. 59; ISSN TANSA; ISSN 0003-018X
Country of Publication:
United States
Language:
English