0000000000951945
AUTHOR
J. Wisniewski
Excited levels in the multishaped 117Pd nucleus studied via β decay of 117Rh
Monoisotopic samples of exotic, neutron-rich 117Rh nuclei, produced in the proton-induced fission of 238U and separated using the IGISOL mass separator coupled to the JYFLTRAP Penning trap, were used to perform β and γ coincidence spectroscopy of 117Pd. The spin parity of the ground state of 117Pd was determined to be 1/2+ and the 19.1 ms isomer at 203.2 keV was assigned a spin-parity 7/2−. The 117Rh β−-decay scheme was considerably extended, and various sequences of the levels were interpreted as resulting from the prolate, oblate, and triaxial nuclear shapes. Some of the β− decays were considered as the allowed Gamow-Teller transitions. The experimental distribution of Gamow-Teller streng…
Shape coexistence in the odd-odd nucleus 98Y : the role of the g9/2 neutron extruder
Excited states in 98Y, populated in neutron-induced fission of 235U and in spontaneous fission of 248Cm and 252Cf, have been studied by means of γ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in 98Y: a deformed one with T1/2 = 180(7) ns and a rotational band on top of it, and a spherical one with T1/2 = 0.45(15)μs, analogous to the 8+ isomer in 96Y, corresponding to the (νg7/2,πg9/2)8+ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in 98Y. This result and the studies of excited le…
Excited states in 87Br populated in β decay of 87Se
Excited levels in 87Br, populated in β decay of 87Se, have been studied by means of γ-ray spectroscopy using an array of broad energy Ge detectors. 87Se nuclei were produced by irradiating a natural Th target with 25-MeV protons. Fission products were extracted from the target chamber using the IGISOL technique, then separated on a dipole magnet and Penning trap (JYFLTRAP) setup. The scheme of excited levels of 87Br has been significantly extended. 114 new transitions and 51 new levels were established. β feedings and log(ft) values of levels were determined. The upper limit for β feeding to the ground state of 87Br was determined to be 23(5)%. Ground state spin and parity 5/2− was confirme…