0000000000589792
AUTHOR
D. T. Scholes
Identification of excited states in doubly odd63140Eu77by recoil-isomer tagging
The 36Ar + 107Ag fusion-evapn. reaction was used to search for isomeric states in the N = 77 isotope 140Eu near the proton-drip line. The recoiling nuclei were implanted into a Si detector, at the focal plane of a gas-filled separator, where prompt and delayed g-ray transitions were correlated across isomeric states using recoil-isomer tagging. The feeding and decay of a new 299(3) ns isomeric state was established. This measurement represents the first observation of excited high-spin states in 140Eu. The behavior of the new states above the isomer is discussed in terms of theor. calcns. based upon the cranked-shell model and upon the exptl. systematics of other N = 77 isotones. Within thi…
Decay of aπh11/2⊗νh11/2microsecond isomer in61136Pm75
An experiment has been performed to populate several extremely neutron-deficient nuclei around the mass-140 region of the nuclear chart, using a beam of {sup 54}Fe on a {sup 92}Mo target at an energy of 315 MeV. Analysis of these data using recoil-isomer tagging has established that the yrast {pi}h{sub 11/2} x {nu}h{sub 11/2},J{sup {pi}}=(8{sup +}), bandhead state in {sup 136}Pm is isomeric with a half-life of 1.5(1) {mu}s. This isomeric state decays via a 43-keV, probable-E1 transition to a J{sup {pi}}=(7{sup -}) state. Consideration of the theoretical Nilsson orbitals near the Fermi surface suggests that the J{sup {pi}}=(8{sup +}) state has a {nu}h{sub 11/2}[505](11/2){sup -} x {pi}h{sub …
Mass-140 isomers near the proton dripline
An experiment has been performed in Jyvaskyla, Finland, using Jurogam in conjunction with RITU and GREAT. This experiment populated several extremely neutron-deficient nuclei around the mass-140 region of the nuclei chart, using the 92Mo(54Fe, α2n) reaction at 245 MeV. Analysis of these data has revealed several previously unobserved isomeric states, in several nuclei. One of these has been assigned to 143Dy with a half-life of 1.2 ± 0.3 µs. The energies of the prompt γ rays in the band built upon the isomer are in agreement with those previously observed.