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Two complementary real-photon scattering experiments were conducted on the proton-magic 64Ni nucleus to study the dipole response up to its neutron-separation energy of 𝑆𝑛=9.7MeV. By combining both measurements, 87 𝐸⁢1 and 23 𝑀⁢1 transitions were identified above 4.3 MeV. The results of the observed 𝑀⁢1 transitions were compared to shell-model calculations using two different model spaces. It was found that the inclusion of excitations across the 𝑍=28 shell gap in the calculations has a large impact. Furthermore, average cross sections for decays to the ground state (elastic transitions) as well as to lower-lying excited states (inelastic decays) were determined. The corresponding 𝐸⁢1 channel was compared to calculations within the relativistic equation of motion (REOM) framework. Whereas the calculations of highest possible complexity reproduce the fragmentation and overall behavior of the 𝐸⁢1 average elastic cross section well, the predicted absolute cross sections are approximately twice as high as the experimental upper limits even though the latter also include an estimate of the inelastic-decay channel. 

Natural copper is commonly used as cooling and shielding medium in detector arrangements designed to search for neutrinoless double-β decay. Neutron-induced background reactions on copper could potentially produce signals that are indistinguishable from the signals of interest. The present work focuses on radiative neutron capture experiments on Cu63,65 in the 0.4 to 7.5 MeV neutron energy range. The new data provide evaluations and model calculations with benchmark data needed to extend their applicability in predicting background rates in neutrinoless double-β decay experiments. 

Measurements of the Tm169(n,2n)Tm168 cross section have been performed via the activation technique at 13 energies between 8.5 and 15.0 MeV. The purpose of this comprehensive data set is to provide an alternative diagnostic tool for obtaining subtle information on the neutron energy distribution produced in inertial confinement deuterium-tritium fusion experiments at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. The Tm169(n,2n)Tm168 reaction not only provides the primary 14-MeV neutron fluence, but also the important down-scattered neutron fluence, the latter providing information on the density achieved in the deuterium-tritium plasma during a laser shot.