Rhm103production by inelastic gamma scattering in the giant dipole resonance region

Abstract

The cross section of the {sup 103}Rh({gamma},{gamma}{prime}){sup 103}Rh{sup {ital m}} reaction as a function of energy has been studied in the giant dipole resonance region. Natural rhodium was irradiated with bremsstrahlung of an electron beam on a platinum converter for electron energies of 14, 15, 17, 19, 20, and 30 MeV. Induced isomeric activities as a function of beam energy were measured with {gamma}-ray spectrometry using a high-purity Ge detector. The integral cross section obtained from the yield curve was found to be uniformly 22.6{plus minus}4.0 mb MeV for all of the beam energies. The experimental data have been compared with the predictions of a {gamma}-ray cascade model calculation where competing open nucleon emission channels were considered and a spin-dependent preequilibrium correction was applied in addition to the equilibrium transition probabilities. The calculation provided one pronounced peak in the cross section--at the ({gamma},{ital n}) threshold--with an integral of 24.3 mb MeV. Neither the experiments nor the calculation confirmed the existence of a comparable second peak observed in earlier experiments.