88-Mev Gamma-Ray Cross Sections

Abstract

Total cross sections for 88-Mev gamma-rays have been measured in 6 elements by absorption methods to a statistical accuracy of about 1.5 percent. The results expressed in ${\mathrm{cm}}^{2}$/gram are 0.0107, 0.0252, 0.0471, 0.0665, 0.0909, and 0.0973 for the elements Be, Al, Cu, Sn, Pb, and U, respectively. Values appear generally lower than predictions of existing theory by a factor proportional to ${Z}^{2}$.Ratios of pair formation cross sections in different elements have been obtained in a few cases; these data can be used together with the total cross section to obtain non-pair cross sections (presumably Compton scattering). The cross section so obtained at 88 Mev agrees within the experimental accuracy of about 15 percent with the Klein-Nishina prediction for Compton scattering.