Cascadeγdecay study of108Agfollowing thermal and resonance neutron capture in107Ag

Abstract

With the aim to obtain information on the E1 and M1 photon strength functions at g-ray energies below the neutron separation energy, we studied two-step g cascades following the capture of thermal neutrons in 107 Ag. For this purpose, we undertook an experiment with the dedicated facility for two-step g cascades at the Rez ˇ research reactor. The obtained data were discussed in conjunction with previous results from resonance neutron capture measurements with the same isotope, obtained at the GELINA facility of the Institute for Reference Materials and Measurements. The cascade g decay of the 108 Ag compound nucleus has been simulated with the aid of the Monte Carlo algorithm DICEBOX assuming several models for photon strength functions. To interpret the results of the experiments, the outcome from these simulations was confronted with the observed cascade-related quantities. The results indicate that the E1 photon strength function below the neutron binding energy is suppressed with respect to the conventional Brink-Axel model and that the M1 and/or possibly E2 photon strengths may play an important role in the decay of compound nucleus at excitations below '3 MeV.