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

Combined in-beam electron and gamma-ray spectroscopy of 184,186Hg\u2028

By exploiting the SAGE spectrometer a simultaneous measurement of conversion electrons and gamma rays emitted in the de-excitation of excited levels in the neutron-deficient nuclei (184,186)Hg was performed. The light Hg isotopes under investigation were produced using the 4n channels of the fusion-evaporation reactions of (40)Ar and (148,150)Sm. The measured K- and L-conversion electron ratios confirmed the stretched E2 nature of several transitions of the yrast bands in (184,186)Hg. Additional information on the E0 component of the 2(2)(+) -> 2(1)(+) transition in (186)Hg was obtained.

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…

In-beam study of No-253 using the SAGE spectrometer

Evolving collective structures in the transitional nuclei 162W and 164W

Excited states in the neutron-deficient nuclides 162 74 W88 and 164 74 W90 were investigated by using the γ -ray spectrometer Jurogam. A change in structure is apparent from the first rotational alignments in 162W and 164W, whose rotationally aligned bands are interpreted as ν(h9/2) 2 and ν(i13/2) 2 configurations, respectively. The level schemes have been extended using recoil (-decay) correlations with the observation of excited collective structures. Configuration assignments have been made on the basis of comparisons of the deduced aligned angular momentum, as a function of rotational frequency, with the predictions of the cranked shell model. peerReviewed

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

Reinvestigation of the excited states in the proton emitter Lu-151: Particle-hole excitations across the N = Z=64 subshell

In-beam gamma-ray and electron spectroscopy of Md-249,Md-251

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…

Study of shape coexistence in the very neutron deficient nucleus Hg-176

In-beam γ-ray and γ–γ coincidence measurements have been made for the very neutron deficient nucleus 176Hg using the recoil-decay tagging (RDT) technique. The irregular yrast sequence observed to I=10ℏ indicates that the prolate intruder band, seen in heavier Hg isotopes near the neutron midshell, is crossing the nearly spherical ground-state band of 176Hg above I=6ℏ. peerReviewed

Delayed or absent pi(h(11/2))(2) alignment in Xe-111

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