0000000000477983
AUTHOR
A. Khaplanov
Prompt and delayed spectroscopy of 199At
The neutron-deficient nucleus At199 has been studied through γ-ray and electron spectroscopy, using the recoil-decay tagging technique. Two experiments were conducted, using a gas-filled recoil separator with a focal-plane spectrometer alone and together with a germanium-detector array at the target position. The resulting level scheme for At199 includes a new isomer with a half-life of 0.80(5) μs and a spin and parity of (29/2+). The 13/2+ isomer, which de-excites via an M2 transition to the 9/2− ground state, was measured to have a half-life of 70(20) ns. Our earlier version of the level scheme for At197 has been updated as well. peerReviewed
Identification of excited states in 107,52Te55
Excited states in the extremely neutron-deficient nucleus 107Te have been identified from two separate experiments using the recoil-decay tagging technique. Two connected structures were observed on the basis of γγ-coincidence relations and tentatively assigned as built on the mixed-parentage νg7/2d5/2 and νh11/2 intruder configurations. The observed structures were compared with large-scale shell-model calculations and total Routhian surface calculations. Collective behavior was discovered to persist in the νh11/2 band of 107Te which highlights the shape-polarizing effect of a single valence neutron occupying the h11/2 intruder orbit as the N=50 shell closure is approached. peerReviewed
Evidence for enhanced collectivity in Te-I-Xe nuclei near the N = Z = 50 double shell closure
Gamma‐ray transitions have been identified for the first time in the extremely neutron‐deficient Tz = 1 nuclide 110Xe and the energies of the three lowest excited states in the ground‐state band have been deduced. A level scheme has also been constructed for the proton‐unbound, Tz = 3/2 nuclide 109I, exhibiting band structures built on g7/2 and h11/2 states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be built on a g7/2 orbital coupled to an octupole‐vibrational phonon of the 108Te core. The results were obtained in a recoil‐decay tagging experiment using the 58Ni(54Fe,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the hi…
Evidence for octupole collectivity in 172Pt
Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing…