Gamma-ray spectroscopy of191,193Bi

Very neutron-deficient Bi-191,Bi-193 nuclei have been studied at the Department of Physics, University of Jyvaskyla, Finland (JYFL) employing the Jurosphere II Ge-detector array coupled to the gas-filled recoil separator RITU and different tagging techniques. For the first time in heavy odd-mass nuclei, a collective band (oblate) is identified above the 2p-1h (1/2(+)) proton intruder state in Bi-191. In both Bi-191,Bi-193, a band based on isomeric 13/2(+) state has been observed and oblate deformation for this state has been deduced. ispartof: Acta Physica Polonica B vol:32 issue:3 pages:1019-1023 ispartof: location:POLAND, ZAKOPANE status: published

First prompt in-beam gamma-ray spectroscopy of a superheavy element: the 256Rf

Using state-of-the-art γ-ray spectroscopic techniques, the first rotational band of a superheavy element, extending up to a spin of 20 ¯h, was discovered in the nucleus 256Rf. To perform such an experiment at the limits of the present instrumentation, several developments were needed. The most important of these developments was of an intense isotopically enriched 50Ti beam using the MIVOC method. The experimental set-up and subsequent analysis allowed the 256Rf ground-state band to be revealed. The rotational properties of the band are discussed and compared with neighboring transfermium nuclei through the study of their moments of inertia. These data suggest that there is no evidence of a…

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

High K bands in mid-supershell nuclei

The spectrum of prompt conversion electrons emitted by excited 254No nuclei has been measured, revealing discrete lines arising from transitions within the ground state band. A striking feature is a broad distribution that peaks near 100 keV and comprises high multiplicity electron cascades, probably originating from M1 transitions within rotational bands built on high K states. Evidence for the existence of isomeric states in 254No is presented. peerReviewed

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…