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Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched 76Ge and 76Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the 76Ge(n,n'γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β decay of 76Ge. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV γ ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of ~0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported γ rays from levels in 76Ge can be found in the 2039-keV region. [ABSTRACT FROM AUTHOR]

Isospin (T) symmetry assumes charge symmetry and charge independence are explicit in nuclear structure. Whereas charge independence implies the nn, np and pp interactions are the same, charge symmetry states that the nn and pp interactions are equal. The latt_er approximate symmetry is experimentally verified by the comparison of the excited levels lying at about the same energy in light mirror nuclei. Both of these symmetries are broken by the electromagnetic interaction. The neutron facility at the University of Kentucky provides a unique opportunity to examine charge independence, and in particular, charge symmetry from the reduced electromagnetic transition probabilities and neutron scattering cross sections. Here, we use the isospin formalism by Bernstein, Brown and Madsen, which relates the proton and neutron matrix elements, M p and M n respectively, for equivalent excited states in T=1 mirror nuclei (Tz = +/-1). The nucleus 18O has been studied using the (n,n′) reaction in order to measure the neutron cross sections of the 2+1, T=1 state. Using the previously determined proton matrix elements for the Tz = -1 mirror nucleus (18Ne), along with the determination of the neutron matrix element in 18O from neutron scattering, allows an experimental test of charge symmetry in the A=18 mirror system. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

In recent 160Gd(p,t) reaction studies the existence of more than ten 0+ states in 158Gd below 3.0 MeV was revealed. We have examined 158Gd with the (n,n′γ) reaction at neutron energies up to 3.5 MeV to confirm the identification of these states and to determine their lifetimes through DSAM measurements. Gamma-ray excitation function and angular distribution measurements have been performed and γ - γ coincidences have been measured with the KEGS array of detectors. Moderately strong decays are observed from some of these 0+ states. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]