Seminar Details

A Study of 67,68Ni (Z=28) using One- and Two Neutron Transfer Reactions

Piet Van Duppen, University of Leuven, Belgium
Wednesday, April 24, 4:10 PM - Nuclear Science Seminar
NSCL Lecture Hall

While 68Ni (Z = 28 and N = 40) exhibits properties of a doubly-closed shell nucleus [1], recent experiments point to enhanced collectivity in the Fe and Cr isotopes along N = 40 (see e.g. [2]). A possible reason for this enhanced collectivity is the reduction of the N=40 gap and the possible occupancy of the g9/2 and d5/2-s1/2 orbitals just above the N=40 respectively N=50 gap. In order to investigate the neutron single-particle orbitals around N=40 and to further characterize the excited states in 68Ni, one- and two neutron transfer reaction studies were performed at ISOLDE-CERN. Beams of 66Ni (T1/2 = 54.6 h) were post-accelerated to 3 MeV/u to study the 66Ni(d,p)67Ni and 66Ni(t,p)68Ni reactions in inverse kinematics. A highly segmented silicon detector array for proton detection combined with an efficient germanium detector array for gamma detection [3,4] were used to single-out and characterize ground and excited states. Negative (fp) and positive (gds) parity states were identified in 67Ni (Z=28, N=39) hinting to rather low-lying strength of the positive parity states. A comparison with the region around 90Zr (Z=40, N=50), often considered as the ‘mirror’ of 68Ni, shows a distinct difference in the position and population of the d-s positive parity states using one-proton transfer reaction on 88Sr populating states in 89Y(Z=39, N=50). From the two-neutron transfer reaction study, new information on the 0+ states in 68Ni, was extracted. Preliminary results will be presented and discussed. [1] O. Sorlin,- Phys. Rev. Lett. 88, 092501 (2002) [2] W. Rother,- Phys. Rev. Lett. 106, 022502 (2011) [3] V. Bildstein,- Eur. Phys. J. A 48, 85 (2012) [4] N. Warr,- Eur. Phys. J. A 49, 40 (2013)