Warrington, United Kingdom
Warrington, United Kingdom

Time filter

Source Type

Lica R.,CERN | Lica R.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Rotaru F.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Borge M.J.G.,CERN | And 44 more authors.
Physical Review C | Year: 2017

The β- decay of Mg34 was used to study the Al34 nucleus through γ spectroscopy at the Isotope Separator On-Line facility of CERN. Previous studies identified two β-decaying states in Al34 having spin-parity assignments Jπ=4- dominated by the normal configuration π(d5/2)-1 - ν(f7/2) and Jπ=1+ by the intruder configuration π(d5/2)-1 - ν(d3/2)-1(f7/2)2. Their unknown ordering and relative energy have been the subject of debate for the placement of Al34 inside or outside the N=20 "island of inversion." We report here that the 1+ intruder lies only 46.6 keV above the 4- ground state. In addition, a new half-life of T1/2=44.9(4)ms, that is twice as long as the previously measured 20(10) ms, has been determined for Mg34. Large-scale shell-model calculations with the recently developed sdpf-u-mix interaction are compared with the new data and used to interpret the mechanisms at play at the very border of the N=20 island of inversion. © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.


Lica R.,CERN | Lica R.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Mach H.,National Center for Nuclear Research | Fraile L.M.,Complutense University of Madrid | And 63 more authors.
Physical Review C | Year: 2016

The levels in Sn129 populated from the β- decay of In129 isomers were investigated at the ISOLDE facility of CERN using the newly commissioned ISOLDE Decay Station (IDS). The lowest 1/2+ state and the 3/2+ ground state in Sn129 are expected to have configurations dominated by the neutron s1/2 (l=0) and d3/2 (l=2) single-particle states, respectively. Consequently, these states should be connected by a somewhat slow l-forbidden M1 transition. Using fast-timing spectroscopy we have measured the half-life of the 1/2+ 315.3-keV state, T1/2= 19(10) ps, which corresponds to a moderately fast M1 transition. Shell-model calculations using the CD-Bonn effective interaction, with standard effective charges and g factors, predict a 4-ns half-life for this level. We can reconcile the shell-model calculations to the measured T1/2 value by the renormalization of the M1 effective operator for neutron holes. © 2016 authors. Published by the American Physical Society.

Loading STFC Daresbury collaborators
Loading STFC Daresbury collaborators