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.

• Received 28 July 1958

DOI:https://doi.org/10.1103/PhysRev.112.1267