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Detailed fine-structure $\alpha$ -decay studies of 188,190Bi were performed using the complete-fusion reactions of 50,52Cr ions with a 142Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil- $\alpha$ , recoil- $\alpha$ - $\gamma$ /X-ray and excitation function measurements. Improved data on the $\alpha$ -decay of 188,190Bi were obtained and a number of new low-lying excited states in the daughters 184,186Tl were observed. An intruder, presumably 10- state was identified in 184Tl, extending the systematics of such states in the odd-odd Tl nuclei beyond the neutron mid-shell at N = 104. Some technical aspects of experiment at recoil separators are also discussed.

The JYFL gas-filled recoil separator RITU, combined with Ge detector arrays and a SACRED magnetic solenoid spectrometer, has been successfully employed in recoil-decay-tagging (RDT) experiments in order to probe structures of very neutron-deficient heavy nuclei. The present contribution focuses on the light Pb region where the new data extend the systematics of shape-coexisting yrast states towards the proton dripline. Similarities between band structures and their relation to possible multi-particle multi-hole intruder excitations will be discussed.

First and preliminary results of an experiment aimed at measuring g -factors of isomeric states in neutron-rich nuclei in the vicinity of 68 Ni are reported. Isomers near the predicted N =40 sub-shell closure in 69 Cu, 67 Ni and 66 Co have been populated in the fragmentation of a 76 Ge, 61.4 MeV/u beam onto a 145 mg/cm 2 9 Be target at GANIL. Here we report the results for the 357(2) ns, I π =13/2 + isomer in 69 Cu for which a preliminary gyromagnetic ratio of | g |=0.195(9) was derived. The Larmor precession of the spin-oriented isomeric ensemble was measured by recording γ –ion correlations in a 20 μs time window. This pioneering experiment has indicated interesting nuclear structure information and shows promising possibilities for future studies of this kind.

In this overview, some latest results from gamma-ray spectroscopic studies of high spin states of isobaric multiplets will be presented. An experimental programme is underway to examine exited states of isobaric multiplets of total isospin T=1/2 and T=1 and the comparison of energies of excited states can be interpreted in terms of Coulomb effects. Through a systematic study of these Coulomb effects, and through examination of the calculated Coulomb energies from full pf-shell model calculations, it is now becoming clear that measurement of Coulomb energies can yield very detailed information on the evolution of nuclear structure phenomena as a function of energy and angular momentum. In this contribution, latest results of studies of isobaric analogue states at high spin in the A=50, 51 and 53 systems will be presented.

We report results from a pioneering experiment to measure the g factors of isomeric states of neutron-rich nuclei around 68Ni, far from the valley of β stability.For the first time, the time-dependent perturbed angular distribution method was applied in combination with the heavy-ion-γ correlation technique to study g factors of spin-aligned isomers produced in a projectile fragmentation reaction and mass-separated. Some technical aspects are discussed and illustrated with preliminary results.

New microsecond isomers in the neutron-deficient isotopes 189g, 190Bi have been identified after in-flight separation by the velocity filter SHIP. The evaporation residues were identified on the basis of delayed recoil-γ/X-ray, recoil-γ/X-ray-α and excitation function measurements. The systematics of the [ π1i 13/2]13/2+ excited states in the odd-mass Bi nuclei is discussed.

Two excited J(pi)=0(+) states in Pb-186 populated in the a-decay of Po-190 have been identified through alpha -particle/conversion electron coincidences in an experiment at the velocity filter SHIP ...

New neutron-deficient isotopes 188,189Po have been produced in the complete fusion reaction of 52Cr ions with a 142Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of α-γ and α-conversion electron coincidence measurements and of α-α position and time correlations. In 189Po a ground state to ground state α decay with Eα1= 7540(20) keV, T1/2= 5(1) ms and two fine structure α-decays at Eα2= 7264(15) keV and Eα3= 7316(15) keV have been observed. In 188Po (T1/2= 400+200 −150μs) a ground state to ground state α decay at Eα= 7915(25) keV and a fine structure α decay at Eα= 7350(40) keV have been found. Improved data on the α-decay of 189Bi were obtained.

The decays of 25 57 Mn32 and 25 58 Mn33 have been studied with the 8π Spectrometer following the reaction 48Ca(13C,pxn)60 − x Mn at a beam energy of 40 MeV. The level schemes of these two nuclei have been extended, and the multipolarities of the observed transitions have been determined.

In-beam γ-ray spectroscopy measurements provide important information on coexisting normal and intruder configurations in lead nuclei. However, in these experiments the yrast states are preferentially populated so that in many cases nothing is known about non-yrast states that are essential for obtaining a fuller understanding. Complementary experiments designed to study fine structure in the a decays of polonium nuclei have led to the discovery of low-spin non-yrast states in the daughter lead nuclei, while higher-spin states can be identified through the γ decays of isomeric states. The α-decay studies have the additional benefit of allowing information on configuration mixing in the polonium parents to be deduced from the measured hindrance factors.

High-spin states in the odd–odd N=Z nucleus 5025Mn have been investigated. A sequence of states up to Jπ=6+ has been assigned as the T=1 analogue of the yrast band in 5024Cr for the first time. The differences in energy between levels in these bands are interpreted in terms of rotational alignments and the effect they have on the Coulomb energy of the nucleus. Comparisons with shell model calculations show that the Coulomb energy difference between the T=1 analogue structures is an important indicator of the competition between isovector pairing modes in N=Z nuclei and their isobars.

Gamma decays from excited states in the ${T}_{z}=\ensuremath{-}\frac{1}{2}$ nucleus ${}^{51}$Fe have been observed for the first time. The differences in excitation energies as compared with those of the mirror partner, ${}^{51}$Mn, have been interpreted in terms of Coulomb effects and the resulting Coulomb energy differences (CED) can be understood intuitively in terms of particle-alignment effects. A new CED effect has been observed, in which different CED trends have been measured for each signature of the rotational structures that characterize these mid-${f}_{7/2}$ shell nuclei. Large-scale $\mathrm{fp}$-shell model calculations have been used to compute the trends of the CED as a function of spin. The result of comparing these calculations with the data demonstrates an ability to reproduce the fine details of the Coulomb effects with a precision far greater than has been previously achieved.

Two new rotational bands have been observed in the Dy-152 nucleus following experiments performed using the EUROGAM gamma-ray spectrometer. Several transitions have been observed that link these new bands into the known single-particle states. Using the Doppler shift attenuation method, the quadrupole moment of the previously-known rotational sequence has been measured. The value of Q(band) = 3.85+/-0.06 e b confirms the deformed nature of this cascade. The structures of the three bands are discussed in terms of the occupation of both paired and unpaired orbitals, and are found to be in good agreement with theoretical calculations. The observation of two new bands further extends the concept of shape coexistence in the Dy-152 nucleus.

The decay scheme of the N=Z odd-odd nucleus, 62Ga has been deduced for the first time using the reactions 40Ca(24Mg,pn)62Ga and 40Ca(28Si,αpn)62Ga at beam energies of 65 MeV and 88 MeV respectively. Transitions from excited states in 62Ga were identified using the PEX apparatus at the Niels Bohr Institute Tandem Accelerator Laboratory. Gamma ray angular correlation data collected using the AYEBALL array at the Argonne National Laboratory are consistent with a cascade of stretched E2 transitions which decay from a spin 1+ bandhead via a pure magnetic dipole decay, directly linking a proposed T=0 structure with the T=1, Jπ=0+ ground state.

gamma-spectroscopy methods have been used to search for microsecond isomers among the fragmentation products of a 1 GeV/nucleon Pb-208 beam. In particular the population of the known K-pi = 35/2(-) isomer in W-179 has been investigated and several new isomeric decays have been found for neutron rich nuclei in the A approximate to 180-200 mass region. The ground state band of the neutron rich N = 116 system of W-190 has been identified for the first time and we discuss its structure in comparison to neighboring systems.