Attenuation of Gamma Radiation Through Two-Legged Rectangular Ducts and Shelter Entranceways. An Analytical Approach

Abstract

To improve existing knowledge on gamma and neutron shielding properties of shelters. ABSTRACTAn analytical approach is developed to permit determination of gamma radiation attenuation as it passes through two-legged rectangular ducts and shelter entranceways.The approach used employs the albedo concept for wall scattering and includes correction terms necessary to account for the "corner lip effect." With appropriate simplifying assumptions, moderately simple engineering formulas are obtained. Actual use of the formulas requires better knowledge of differential angular albedo than is presently available; however, by assuming isotropic distribution of the albedo function, a very good comparison of experimental information with results calculated by this technique is obtained.

Further Analysis of Gamma Ray Attenuation in Two-Legged Rectangular Ducts

“…(1 -P 2 ) a 6 -2 2 a 8 P +-aL 1 = 725,000 roentgens-cm (The fact that this figure is, astonishingly, larger than the value of Du, the reading in open air, is due to the hypothetical nature of the concc.pt that the radiation scattered from an area of the side wall near the opening is considered to be concentrated Into a single point. )…”

Methods for Calculating Effects of Ducts, Access Ways, and Holes in Radiation Shields

“…A method of calculating gamma-ray transmission through two-legged rectangular ducts was formulated by LeDoux and Chilton, 16 and the same general technique was used by Song 13 for neutron transmission. Equations were derived for calculating radiation streaming down two-legged concrete ducts using as transport mechanisms: (1) a singlereflection albedo for surfaces that can be "seen" by both the source and the detector, and (2) scattering by material in the corner lip of the duct.…”