D. O'Donnell

Low-lying excited states in the neutron-deficient isotopes Os-163 and Os-165

Excited states in the neutron-deficient isotopes 163Os and 165Os were identified using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. The 163Os and 165Os nuclei were populated via the 106Cd(60Ni,3n) and 92Mo(78Kr,2p3n) reactions at bombarding energies of 270 MeV and 357 MeV, respectively. Gamma-ray emissions from these nuclei have been established unambiguously using the recoil-decay tagging technique and a coincidence analysis has allowed level schemes to be established. These results suggest that the yrast states are based upon negative-parity configurations originating from the νf7/2 and νh9/2 orbitals.

Characterizing the atomic mass surface beyond the proton drip line via α-decay measurements of the πs1/2 ground state of 165Re and the πh11/2 isomer in 161Ta

The α-decay chains originating from the πs1/2 and πh11/2 states in 173Au have been investigated following fusion-evaporation reactions. Four generations of α radioactivities have been correlated with 173Aum leading to a measurement of the α decay of 161Tam. It has been found that the known α decay of 161Ta, which was previously associated with the decay of the ground state, is in fact the decay of an isomeric state. This work also reports on the first observation of prompt γ rays feeding the ground state of 173Au. This prompt γ radiation was used to aid the study of the α-decay chain originating from the πs1/2 state in 173Au. Three generations of α decays have been correlated with this state, leading to the observation of a previously unreported activity which is assigned as the decay of 165Reg. This work also reports the excitation energy of an α-decaying isomer in 161Ta and the Qα value of the decay of 161Tag.

Transition probability studies in 175Au

Transition probabilities have been measured between the low-lying yrast states in 175Au by employing the recoil distance Doppler-shift method combined with the selective recoil-decay tagging technique. Reduced transition probabilities and magnitudes of transition quadrupole moments have been extracted from measured lifetimes allowing dramatic changes in nuclear structure within a low excitation-energy range to probed. The transition quadrupole moment data are discussed in terms of available systematics as a function of atomic number and aligned angular momentum.

The influence of quasineutron configurations on 161Ta and nearby odd‐A nuclei

Several strongly coupled bands in the neutron‐deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h9/2) and ν(i13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd‐A nuclei populated with much lower reaction cross sections in this region at the proton drip line.

gamma-ray spectroscopy of Cl-38(17) using grazing reactions

Excited states of

Gamma-ray spectroscopy of

^{38}_{17}

^{38}_{17}

Cl

Cl using grazing reactions

_{21}

Spectroscopy of {sup 52,53}Sc

were populated in grazing reactions during the interaction of a beam of

Structure of neutron-rich Ar isotopes beyond N=28

^{36}_{16}