ELASTIC-SCATTERING OF EU-152 GAMMA-RAYS BY TUNGSTEN

Differential cross sections for the elastic scattering of 344, 444, 779, 964, 1086, 1112 and 1408 keV gamma rays by tungsten have been measured for six scattering angles ranging from 7 degree to 45 degree and are compared with theoretical cross sections for Rayleigh plus nuclear-Thompson plus, for the 1408 keV case, Delbruck scattering. For small momentum transfers the experimental results are in best agreement with cross sections computed using the Hartree-Fock form factor Rayleigh amplitudes, but at large momentum transfers the experimental results lie below these theoretical cross sections and also those computed using both the ″exact″ Rayleigh amplitudes of Kissel and Pratt and the Dirac point-Coulomb form factor amplitudes. Inclusion of the Papatzacos and Mork Delbruck amplitudes at 1408 keV reduces the difference between experimental and theoretical cross sections for scattering angles less than 25 degree , but worsens the situation for larger angles.