Spectra of two-step gamma cascades following the thermal 162Dy(n,gamma)163Dy reaction have been measured. Distinct peaklike structures observed at the midpoints of these spectra are interpreted as a manifestation of the low-energy isovector M1 vibrational mode of excited 163Dy nuclei.

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With the aim to obtain information on the E1 and M 1 photon strength functions at ␥-ray energies below the neutron separation energy, we studied two-step ␥ cascades following the capture of thermal neutrons in 107 Ag. For this purpose, we undertook an experiment with the dedicated facility for two-step ␥ cascades at the Ř ež 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 ␥ 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 M 1 and/or possibly E2 photon strengths may play an important role in the decay of compound nucleus at excitations below Ϸ3 MeV.

Spectra of two-step y-ray cascades following the thermal-neutron capture in the ' Dy target were measured. Based on a rigorous modeling procedure, the experimental results are compared with their various theoretical predictions. A satisfactory agreement is reached for the F1 strength function described by the Brink-Axel model and the M1 strength function containing a resonance component at Fy=3 MeV. A possible interpretation of this component in terms of the M1 scissors resonance is discussed. PACS number(s): 25.40.Lw, 27.70.+q, 24.60.Dr