Dose Measurements of gamma Radiation Streaming Through Concrete Ducts with and Without Lead Liners and Through Corrugated Steel Ducts

摘要

Dosimeter measurements were taken in a 3-foot-square, two-legged concrete duct, with and without the presence of lead sheets covering the basic scattering areas in the corner, to determine the effectiveness of lead sheeting in reducing gamma radiation. For Co60 radiation, the lead sheets reduced the dose rate in the second leg of the duct down to 46% of the dose rate measured in the second leg of the duct without lead sheets, and for Cs137 radiation the reduction was down to 36%. Calculations were made to determine the effectiveness of the sheets in different size ducts, and comparisons were made with other methods for reducing radiation. Measured attenuation factors for a circular, thin-walled, corrugated steel duct were compared to values calculated by a simple computer program for a square, thick-walled steel duct. It appears that the computer code can be used to approximate attenuation factors for a corrugated steel duct. (Author)