Elastic scattering of 1.17 and 1.33 MeV gamma rays by molybdenum, tantalum and lead

Elastic scattering cross-sections of lead, tantalum and molybdenum were determined with the help of a Ge(Li) detector for 1.17 and 1.33 MeV rays between 30deg and 115 deg. Theoretical evaluations of the cross-sections are based on a coherent addition of the well-known nuclear Thomson scattering amplitudes, the Rayleigh amplitudes calculated by Kissel and Pratt and the Delbrueck amplitudes given by Papatzacos and Mork. The fairly good agreement between experiment and theory reveals the importance of the real Delbrueck amplitudes. However, the experimental results in the 30-60deg range tend to lie slightly but systematically below the calculated cross-sections. (auth.)