Coherent Scattering of 1.17-Mev and 1.33-Mev Gamma Rays through Small Angles

The dependence of the differential cross section for the coherent scattering of 1.17-Mev and 1.33-Mev gamma rays on atomic number was investigated. An empirical procedure, which makes an absolute determination of the cross sections unnecessary, was used to estimate the Compton scattering cross sections. The latter were subtracted from the measured cross sections in order to obtain the relative coherent scattering cross sections, which were found to vary as Zⁿ. Our average value for n is 3.07±{}0.18.The angular distribution of the total (coherent and Compton) scattering cross section was also investigated in the case of copper and lead between 2.43^∘{} and 5.79^∘{}. Our results are compared with the existing theoretical predictions and with the results of the earlier experiments, wherever the latter are available.