The γ-ray strength functions and level densities of 73,74 Ge have been extracted up to the neutron separation energy S n from particle-γ coincidence data using the Oslo method. Moreover, the γ-ray strength function of 74 Ge above S n has been determined from photo-neutron measurements; hence these two experiments cover the range of E γ ≈ 1-13 MeV for 74 Ge. The obtained data show that both 73,74 Ge display an increase in strength at low γ energies. The experimental γ-ray strength functions are compared with M1 strength functions deduced from average B(M1) values calculated within the shell model for a large number of transitions. The observed low-energy enhancements in 73,74 Ge are adopted in the calculations of the 72,73 Ge(n,γ) cross sections, where there are no direct experimental data. Calculated reaction rates for more neutron-rich germanium isotopes are shown to be strongly dependent on the presence of the low-energy enhancement.

The nuclear level densities of [194][195][196] Pt and 197,198 Au below the neutron separation energy have been measured using transfer and scattering reactions. All the level density distributions follow the constant-temperature description. Each group of isotopes is characterized by the same temperature above the energy threshold corresponding to the breaking of the first Cooper pair. A constant entropy excess S = 1. Pt and 197 Au, respectively, giving information on the available single-particle level space for the last unpaired valence neutron. The breaking of nucleon Cooper pairs is revealed by sequential peaks in the microcanonical caloric curve.

The γ-ray strength function (γ SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows measurements of these properties across a wide range of previously inaccessible nuclei. Proton-γ coincidence events from the d(86 Kr, pγ) 87 Kr reaction were measured at iThemba LABS and the γ SF and NLD in 87 Kr was obtained. The low-energy region of the γ SF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The γ SF and NLD are used as input parameters to Hauser-Feshbach calculations to constrain (n, γ) cross sections of nuclei using the TALYS reaction code. These results are compared to 86 Kr(n, γ) data from direct measurements.

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Photoneutron cross sections were measured for 58 Ni, 60 Ni, 61 Ni, and 64 Ni at energies between the one-neutron and two-neutron thresholds using quasi-monochromatic γ-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. The new photoneutron data are used to extract the γ-ray strength function above the neutron threshold complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including 63 Ni, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained γ-ray strength functions from the Hartree-Fock-Bogolyubov plus quasiparticle-random phase approximation based on the Gogny D1M interaction for both E1 and M 1 components and supplemented with the M 1 upbend.