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The nuclear structure in regions of the Segre chart which are of astrophysical importance is reviewed. The main emphasis is put on those nuclei that are relevant for stellar nucleosynthesis in fusion processes, and in slow neutron capture, both located close to stability, rapid neutron capture close to the neutron dripline and rapid proton capture near the proton dripline. The basic features of modern nuclear structure, their importance and future potential for astrophysics and their level of predictibility are critically discussed. Recent experimental and theoretical results for shell evolution far off the stability line and consequences for weak interaction processes, proton and neutron capture are reviewed.

A broad range of physics phenomena can be addressed by high-resolution in-beam γ-ray spectroscopy experiments with radioactive beams offered within the Rare ISotopes INvestigation at GSI (RISING) project. It combines the EUROBALL Ge-Cluster detectors, the MINIBALL Ge detectors, the HECTOR-BaF detectors, and the fragment separator FRS. The secondary beams produced at relativistic energies are used for Coulomb excitation or secondary fragmentation experiments to study projectile like nuclei far off the stability line by measuring de-excitation photons. The physics studied comprises the evolution of shell structure towards the drip lines and its signatures as inferred from excitation energies, mirror symmetry and electromagnetic transition strengths. The first results of the "fast beam campaign" are discussed in comparison to various shell model calculations including the structure of light Sn isotopes based on Coulomb excitation of 108Sn, the discussion of the N = 32,34 sub-shell closure based on neutron-rich 56,58Cr isotopes, and the shell structure in light proton-rich Ca isotopes from the fragmentation of a 37Ca radioactive beam.

Time Differential Perturbed Angular Correlation of gamma-rays (TDPAC) experiments were performed for the first time in the decay of Cu-68m (6(-), 721 keV, 3.75 min) produced at the ISOLDE facility at CERN. Due to the short half-life of the source isotope, the measurements were carried out online. The intermediate state (2(+), 84.1 keV, 7.84 ns) offers the unique opportunity to study the electromagnetic fields acting at a copper probe in condensed matter via hyperfine interactions. The present work allowed determination of the nuclear moments for this state. The electric quadrupole moment vertical bar Q(2(+), 84.1 keV)vertical bar = 0.110(3) b was obtained from an experiment performed in Cu2O and the magnetic dipole moment vertical bar mu vertical bar = 2.857(6) mu(N) from measurements in cobalt and nickel foils. The results are discussed in the framework of shell model calculations and the additivity rule for nuclear moments with respect to the robustness of the N = 40 sub-shell. Copyright (C) EPLA, 2016

Shell-model calculations for the N = 50 nucleus 86Kr are presented and compared to results of recent in-beam experiments. Two model spaces are considered: a pure proton configuration space containing the 0f5/2, 1p=3/2, 1p½, 0g=9/2 orbitals and a model space including additionally the particle-hole excitation generated by one neutron lifted from the 0g9/2 orbital across the shell gap to the 1d=5/2 orbital. The predictions of the shell-model using various sets of residual interactions and based on pure proton excitations are comparable with the experimental findings for the states of positive parity below 4 MeV and for the negative-parity states with spins up to 7−. The inclusion of neutron-core excitations causes an improved agreement between experimental und calculated level energies for the positive-parity yrast states with spins 7h, 9h and 10h. The interpretation of neutron-core excited high-spin states is supported by the comparison of the level structure of 8636Kr50 to the experimental levels of the valence-mirror nucleus 6428Ni36.

The present status of the shell model structure at .t' = Z = 50 is giken. On the basis of recent and previous experimental work a shell model description of known nuclei is given resulting in predictions for single particle energies for the doubly magic '"Sn core. Various approaches for the residual (two-body) interaction (empirical, realistic. schematic) were used (and combined), to test their influence on the extrapolated single particle energies. A comparison with the lighter .V = Z doubly magic nuclei "0. and 40Ca and "Ni reveals consistent results for Coulomb shifts, spin-orbit splitting and proton-neutron symmetry. There are first indications for dripline effects breaking the isospin symmetry. The results are used to discuss future experiments and their relevance for the determination of the '"OSn shell model parameters.

In-beam spectroscopic investigations of 109Sn have been performed using the reactions 55Mn(58Ni, 3pn) and 106Cd(α, n) with E58Ni = 240 MeV and Eα = 23 MeV, respectively. An extended level scheme of 109Sn is presented showing high-spin states up to Ex ≈ 8 MeV with Jπ = (41/2+). The problem of the 109Sn ground state has been solved identifying a 12.8 keV transition deexciting the 7/2+ state to the 5/2+ g.s. A half-life of T½ = 7(1) ns has been measured for the 17/2+ state at Ex = 2114 keV. The experimental data are compared with the predictions of shell-model calculations.

The ?-decay of the neutron deficient nuclei 103In and 100,102Cd has been studied following the reactions 58Ni + 50Cr and 58Ni + 46,48Ti at 250 MeV and 230 MeV bombarding energy of the 58Ni beam, respectively. Evaporation neutrons and charged particles were measured in coincidence with prompt and delayed ?-rays with the multidetector array OSIRIS. To investigate the decay of the I? = 8+ isomers of 100,102Cd a recoil catcher setup inside OSIRIS was used. Six new ?-ray transitions of 100Cd and four of 102Cd with intensities of 1-10% of the main ?-ray cascades were found. Two new states of 100Cd were established and firm spin-parity assignments were made to all states below the isomer. These new states were identified as the 4+ and the 6+ members of the proton ?g9/2?2 multiplet. The experimental states of 103In and of 100,102Cd are compared to shell model predictions in the ?(p1/2, g9/2) v(d5/2, g7/2, s1/2, d3/2, h11/2) configuration space.

The level scheme of 208Pb is now nearly complete up to 5 MeV excitation energy from measurements of 209Bi(t, αγ)208Pb, 207Pb(d, pγ)208Pb, and γ-spectroscopy with inelastic scattering of 64Ni and 82Se. Also a complete set of M1- and E2-matrix elements is available from experiments or calculations, that allows us to evaluate γ-branching ratios quantitatively. This information together with the spectroscopic factors is sufficient to derive wave functions for many states strictly from the experimental data. The Ansatz for the wave functions is, that they are orthonormal superpositions of the lowest one-particle one-hole states. Redundant data are often well reproduced. Matrix elements of the residual interaction are calculated from the wave functions; they are compared with realistic Kuo-Brown matrix elements and the surface-delta interaction.

Neutron deficient nuclei with mass numbers A approximate to 90 and 40 less than or equal to Z less than or equal to 44 have been studied making use of the Osiris and Nordball spectrometers. The high spin states of these nuclei and their electromagnetic decay properties are compared to shell model calculations based on the core Sr-88 and using different parametrizations of the residual interaction. The dependence of the mean square deviations of experimental and theoretical level energies, branching ratios, and transition probabilities on the neutron numbers N = 46-50 and the validity of seniority as a good quantum number are discussed.

The mass of 40Ti has been determined by using the isobaric multiplet mass equation method. The experimental data of the 40Ti β-decay were used to determine the level of the isospin analogue state of 40Sc. The ground-state mass excess and the QEC value for 40Ti were determined to be -9060±12 keV and 11 466 ± 13 keV, respectively.

Lifetimes of low-lying states in 123,123Cs and 120,122XE are measured using the recoil-distance Doppler-shift method. The investigated nuclei were produced by the 107Ag+18O and 109Ag+18O reactions. The negative-parity states in 121,123Cs are described in the framework of the core-quasiparticle coupling model with gamma -soft (the extended Wilets-Jean model) and rigid (the Davydov-Filippov model) cores. The comparison of experimental and theoretical reduced E2 transition probabilities between the yrast negative-parity states in 121,123Cs seems to indicate that the corresponding cores cannot be fully gamma -soft as in the completely gamma -unstable model of Wilets and Jean (1956). This does not necessarily mean that the cores are as rigid as the Davydov-Filippov model assumes, but rather indicates a localization of the nucleus in the prolate ( gamma

The gamma-decay of excited states in the neutron deficient isotopes Tc-87 and Tc-88 has been observed for the first time. The fusion-evaporation reactions Ni-58(S-32, p2n)Tc-87 and Ni-58(S-32, pn)Tc-88 at 110 MeV, Ca-40(Cr-50, p2n)Tc-87 and Ca-40(Cr-50, pn)Tc-88 at 170 MeV and Ni-58(Ar-36, alpha-pn)Tc-88 at 145 MeV beam energy were used. Unambiguous identification of these nuclei which are populated with less than 1 mb cross section was achieved with coincidences between the gamma-radiation and the evaporation residues detected in a recoil mass separator. From gamma-gamma-coincidence data, a decay scheme of 11 transitions was constructed for Tc-88, the ground state of which is suggested to have I-pi = 7- or 8+. Two transitions identified in Tc-87 follow the pattern of a g9/2 one-quasiparticle band. (Less)

This work is supported by the Science and Technology Facilities Council (STFC), UK, US Department of Energy, Office of Nuclear Physics, under Contract No. DEAC02-06CH11357 and DE-FG02-94ER40834, NSF grant PHY-1404442.

The RISING setup at the GSI-FRS facility was used to investigate the isomer and beta decays in N~Z~50 Cd, Ag and Pd isotopes. A preliminary analysis of the data has revealed new results on the Tz=1, 94Pd, 96Ag and 98Cd isotopes. In 94Pd a new high-spin isomer was observed, whilst in 96Ag 3 new isomeric states were identified, including core-excited states. In 98Cd a new high-energy isomeric γ-ray transition is observed, thus enabling us to confirm the previous spin assignment for the core-excited 12+ isomer.

We report on g-factor measurements of the 19/2+ T1/2=4.5(3) μs isomer in 127Sn and the 10+ T1/2=2.69(23) μs isomer in 128Sn. These isomers were produced and spin-aligned in relativistic heavy-ion fragmentation at GSI and were selected and separated by the GSI fragment separator (FRS). The γ-rays of the isomeric decay were detected by the RISING γ-ray spectrometer. The method of time-differential perturbed angular distributions was utilized. The measured g-factors, g(19/2+; 127Sn)=− 0.17(2) and g(10+; 128Sn)=− 0.20(4), are compared with shell model calculations. The measured g-factors confirm the predominantly νh11/2− 2 and ν(s1/2− 1h11/2−2) character of the 10+ and 19/2− isomers in 128Sn and 127Sn, respectively. The results demonstrate the feasibility of the method for similar measurements in exotic neutron-rich nuclei.

In 98Cd a new high-energy isomeric γ-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the 98Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100Sn are discussed.

High-spin states in 70,72Se have been extended up to spin 14+ and 28+, respectively. The yrast bands in both nuclei exhibit a very regular rotational pattern up to the highest spins observed, with no indication of band crossings above hw approximately=0.5 MeV. According to deformed shell modeling calculations the regular yrast structures can be associated with aligned configurations involving g9/2 quasiparticles.

Calculates analytically the energy gained by an electron during one transit of an idealized one dimensional magnetic mirror field B in the presence of a given microwave electric field. The heating rate is defined as this energy gain over the transit time. It depends on the initial energy and the position of the turning point of the electron. The heating rate for relativistic electrons not crossing the resonance surfaces can be comparable to that of 'resonant electrons'. A comparison of the heating rate and energy loss rates from multiple collisions and radiation suggests an equilibrium at energies of 102-103 keV, depending on the mirror ratio, microwave field strength and frequency, and the density of the cold electron group responsible for the collisional energy losses. The fraction of electrons heated to this equilibrium energy is calculated.