Gamma-ray spectroscopy in the decay of (83)Se to levels of (83)Br.
High-resolution γ ray spectroscopy experiments have been done to study the emissions from the radioactive decay of 22-min (83g)Se produced from neutron capture using samples of enriched (82)Se. Energy and intensity values have been obtained to roughly an order of magnitude greater precision than in previous studies. Based on energy sums, 2 new levels are proposed in the daughter (83)Br and one previously proposed level is shown to be doubtful. Some 25 new transitions appear to decay with the (83)Se halflife, about half of which can be accommodated among the previous or newly proposed levels. Several previous γ ray placements are shown to be inconsistent with the new determinations of the (83)Br energy levels, but cannot be accommodated anywhere else among the known levels. As a result of the missing γ ray placements, some of the β branchings in the decay to levels of (83)Br appear to be negative. Gamma rays from the 2.4-h decay of the daughter (83)Br to levels of (83)Kr have also been observed, along with decays of (81g)(,m)Se present as a small impurity in the enriched samples and also as a strong component in irradiated samples of natural Se.
Atlas of Nuclear Isomers
We present an atlas of nuclear isomers containing the experimental data for the isomers with a half-life ≥ 10 ns together with their various properties such as excitation-energy, half-life, decay mode(s), spin-parity, energies and multipolarities of emitted gamma transitions, etc. The ENSDF database complemented by the XUNDL database has been extensively used in extracting the relevant data. Recent literature from primary nuclear physics journals, and the NSR bibliographic database have been searched to ensure that the compiled data Table is as complete and current as possible. The data from NUBASE-12 have also been checked for completeness, but as far as possible original references have been cited. Many interesting systematic features of nuclear isomers emerge, some of them new; these are discussed and presented in various graphs and figures. The cutoff date for the extraction of data from the literature is August 15, 2015.
Nuclear orientation study of the decay of 169Lu
The level structure of 169Yb and the nature of the linking transitions have been studied by radioactive decay of 169Lu polarised at low temperatures in a gadolinium host. Anisotropies of 112 gamma rays in 169Yb have been measured. Unambiguous spin assignments have been made for a number of levels below 2 MeV and multipole mixing ratios of about 90 transitions have been deduced. In particular, it has been found that the 1070.8 keV 7/2+ to 7/2+ transition has delta =0.74-0.13+0.11 or 10.3-4.5+50.1 and from the experimental alpha K value an E0:E2 mixing ratio of mod q mod =5.8+or-0.8 or 3.55+or-0.16, respectively, has been obtained. The energy and structure of individual levels, reduced E2 and M1 transition probabilities and E2:M1 mixing ratios have been calculated using the quasiparticle-phonon model including a Coriolis interaction. In general, good agreement is obtained between the theoretical predictions and the experimental results.