Elastic Scattering of 1.6-Mev Gamma Rays from H, Li, C, and Al Nuclei

The elastic scattering of 1.6-Mev gamma rays from H, Li, C, and Al has been measured at an angle of 124^∘{}. The ratios of the measured differential cross sections to the classical Thomson differential cross sections are 0.94±{}0.16 for H, 0.92±{}0.10 for Li, 1.06±{}0.10 for C, and 1.15±{}0.10 for Al. These results agree with the field-theory prediction that in the low photon-energy limit the cross section must approach the classical Thomson cross section.