Spectroscopy of Hf-161 from low to high spin

High-spin states of Th-218

Spectroscopy of 70Kr and isospin symmetry in the T = 1 f pg shell nuclei

International audience; The recoil-β tagging technique has been used in conjunction with the 40 Ca(32 S ,2n) reaction at a beam energy of 88 MeV to identify transitions associated with the decay of the 2 + and, tentatively, 4 + states in the nucleus 70 Kr. These data are used, along with previously published data, to examine the triplet energy differences (TED) for the mass 70 isobars. The experimental TED values are compared with shell model calculations, performed with the JUN45 interaction in the fpg model space, that include a J = 0 isospin nonconserving (INC) interaction with an isotensor strength of 100 keV. The agreement is found to be very good up to spin 4 and supports the expectat…

Fine structure in the a decay of Lu-156 and Ta-158

Evidence for octupole collectivity in $$^{172}{\mathrm {Pt}}$$172Pt

Multiple chiral bands in Nd-137

alpha-spectroscopy studies of the new nuclides Pt-165 and Hg-170

First identification of rotational band structures in Re-166(75)91

Excited states in the odd-odd, highly neutron-deficient nucleus 166Re have been investigated via the 92Mo(78Kr, 3p1n) 166Re reaction. Prompt γ rays were detected by the JUROGAM II γ -ray spectrometer, and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and implanted into the Gamma Recoil Electron Alpha Tagging spectrometer located at the RITU focal plane. The tagging and coincidence techniques were applied to identify the γ -ray transitions in 166Re, revealing two collective, strongly coupled rotational structures, for the first time. The more strongly populated band structure is assigned to the πh11/2[514]9/2− ⊗ ν…

Excited states in Ra-217 populated in the alpha decay of Th-221

Single-particle and collective excitations in the transitional nucleus 166Os

The mean lifetimes of the lowest energy 2+, 8+ and 9− states in 166Os have been measured using the recoil distance Doppler-shift method in conjunction with a selective recoil-decay tagging technique. These measurements extend studies into the most neutron-deficient mass region accessible to current experimental methods. The B(E2; 2+ → 0+) = 7(2) W.u. extracted from these measurements is markedly lower than those observed in the heavier even-mass Os isotopes. The 8+ and 9− states yield reduced transition probabilities that are consistent with single-particle transitions. While these values may indicate a departure from collective structure, the level scheme and the underlying nuclear configu…

α -decay spectroscopy of the N=130 isotones Ra 218 and Th 220: Mitigation of α -particle energy summing with implanted nuclei

An analysis technique has been developed in order to mitigate energy summing due to sequential short-lived α decays from nuclei implanted into a silicon detector. Using this technique, α-decay spectroscopy of the N=130 isotones Ra218 (Z=88) and Th220 (Z=90) has been performed. The energies of the α particles emitted in the Ra218→Rn214 and Th220→Ra216 ground-state-to-ground-state decays have been measured to be 8381(4) keV and 8818(13) keV, respectively. The half-lives of the ground states of Ra218 and Th220 have been measured to be 25.99(10) μs and 10.4(4) μs, respectively. The half-lives of the ground states of the α-decay daughters, Rn214 and Ra216, have been measured to be 259(3) ns and …

alpha-decay spectroscopy of the N=130 isotones Ra-218 and Th-220: Mitigation of alpha-particle energy summing with implanted nuclei

Fine structure in the alpha decay of high-spin isomers in Lu-155 and Hf-156

Proton emission from an oblate nucleus Lu-151

Production cross section and decay study of Es-243 and Md-249

In the study of the odd-Z, even-N nuclei Es-243 and Md-249, performed at the University of Jyvaskyla, the fusion-evaporation reactions Au-197(Ca-48, 2n)Es-243 and Tl-203(Ca-48, 2n) Md-249 have been used for the first time. Fusion-evaporation residues were selected and detected using a gas-filled separator coupled with its focal-plane spectrometer. For Es-243, the recoil decay correlation analysis yielded a half-life of 24 +/- 3 s and a maximum production cross section of 37 +/- 10 nb. In the same way, a half-life of 26 +/- 1 s, an alpha-branching ratio of 75 +/- 5%, and a maximum production cross section of 300 +/- 80 nb were determined for Md-249. The decay properties of Es-245, the daught…

De-excitation of the strongly coupled band in Au-177 and implications for core intruder configurations in the light Hg isotopes