GEOMETRICAL ATTENUATION FACTORS FOR GAMMA RADIATION FROM CYLINDRICAL AND SPHERICAL SURFACE SOURCES

摘要

The analysis of many types of shielding problems involves the calculation of the radiation flux from a distributed surface source, with geometrical attenuation by divergence of the radiation, but unattenuated by shielding material between the source the detector. In some cases, the source of radiation closely approximates a true surface source, as in the case of bremsstrahlung radiation from a pipe of material of high atomic number containing a beta-active liquid metal of low atomic number. More frequently, an equivalent surface source distribution may be derived for a simple-geometry volume source distribution.nThis report formulates a method for deriving geometrical attenuation factors of distributed surface sources, and presents them in the form of curves for cylindrical and concave spherical geometries. The factors are plotted versus the ratio, d/R, of the detector-source sep¬aration to the radius of the source.