Coulomb excitation of 73Ga

The 𝐵⁡(𝐸⁢2;𝐼𝑖→𝐼𝑓) values for transitions in 71
31⁢Ga40 and 73
31⁢Ga42 were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of
71,73
Ga
at the REX-ISOLDE on-line isotope mass separator facility. The emitted 𝛾 rays were detected by the MINIBALL 𝛾-detector array, and 𝐵⁡(𝐸⁢2;𝐼𝑖→𝐼𝑓) values were obtained from the yields normalized to the known strength of the 2+→0+ transition in the
120
Sn
target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the 𝐸2 collectivity toward lower excitation energy when adding neutrons beyond 𝑁=40. This supports conclusions from previous studies of the gallium isotopes, which indicated a structural change in this isotopic chain between 𝑁=40 and 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2− spin and parity for the ground state, the extracted results revealed evidence for a 1/2−,3/2− doublet near the ground state in 73
31⁢Ga42 differing by at most 0.8 keV in energy.

Authors: J. Diriken, I. Stefanescu, D. Balabanski, N. Blasi, A. Blazhev, N. Bree, J. Cederkäll, T.E. Cocolios, T. Davinson, J. Eberth, A. Ekström, D.V. Fedorov, V.N. Fedosseev, L.M. Fraile, S. Franchoo, G. Georgiev, K. Gladnishki, M. Huyse, O.V. Ivanov, V.S. Ivanov, J. Iwanicki, J. Jolie, T. Konstantinopoulos, Th. Kröll, R. Krücken, U. Köster, A. Lagoyannis, G. Lo Bianco, P. Maierbeck, B.A. Marsh, P. Napiorkowski, N. Patronis, D. Pauwels, P. Reiter, M. Seliverstov, G. Sletten, J. Van de Walle, P. Van Duppen, D. Voulot, W.B. Walters, N. Warr, F. Wenander, K. Wrzosek

Doi: 10.1103/PhysRevC.82.064309

Issue number:

Journal: Phys. Rev. C

Page number: 064309

Published on: 2010-12-13

Year: