https://doi.org/10.1140/epja/i2018-12482-9
Regular Article - Experimental Physics
Lifetimes of excited states in triaxially deformed 107Tc and 109,111,113Rh
1
Department of Physics, University of Oslo, Oslo, Norway
2
Irfu, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
3
Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DRF - CNRS/IN2P3, Bvd Henri Becquerel, 14076, Caen, France
4
Institut für Kernphysik, Universität zu Köln, Köln, Germany
5
Institute of Nuclear Sciences “Vinca”, University of Belgrade, Belgrade, Serbia
6
CSNSM, IN2P3, Orsay, France
7
Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
8
Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Padova, Italy
9
INFN Sezione di Padova, Padova, Italy
* e-mail: andreas.gorgen@fys.uio.no
Received:
23
December
2017
Accepted:
15
February
2018
Published online:
28
March
2018
Lifetimes of excited states in 107Tc, 109Rh, 111Rh, and 113Rh were measured at GANIL using the Recoil-Distance Doppler Shift method. The neutron-rich nuclei were produced in fission reactions in inverse kinematics with a 238U beam impinging on a 9Be target. Fission fragments were identified event-by-event in the ray-tracing spectrometer VAMOS++ and correlated with prompt rays observed around the target position with the EXOGAM Ge detector array. Several lifetimes were obtained for states in the positive-parity yrast bands in the four nuclei and compared to triaxial particle-rotor calculations. The results clarify the configuration for the strongest positive-parity band in 107Tc and suggest a gradual increase of triaxial deformation with atomic number Z, reaching almost maximum triaxiality for the neutron-rich Rh nuclei.
© SIF, Springer-Verlag GmbH Germany, part of Springer Nature, 2018