Eur. Phys. J. A (2008) 35: 159-165
https://doi.org/10.1140/epja/i2007-10530-3

Regular Article - Experimental Physics

Studies of quadrupole collectivity in the γ -soft ¹⁰⁶Ru

¹ Department of Nuclear and Particle Physics, Uppsala University, P.O. Box 535, SE-751 21, Uppsala, Sweden
² Institute for Structure and Nuclear Astrophysics, University of Notre Dame, 46616, Notre Dame, IN, USA
³ Department of Chemistry, University of Oslo, P.O. Box 1033, N-03150, Blindern, Norway
⁴ Department of Physics, University of Jyväskylä, P.O. Box 35, FIN-40351, Jyväskylä, Finland
⁵ School of Physics and Space Research, University of Birmingham, B15 2TT, Birmingham, UK
⁶ Faculty of Physics, University of Warsaw, ul. Hoża 69, PL 00-681, Warsaw, Poland

^* e-mail: msvega@ssafara.net

Received: 28 November 2007
Accepted: 31 January 2008
Published online: 26 February 2008

Abstract

Various alternative models were used to describe the structure of ¹⁰⁶Ru . For example, the General Collective Model (GCM) predicts shape-coexistence for ¹⁰⁶Ru with a spherical and a triaxial minimum and strongly mixed structures, while in the IBA-2 calculations, where ¹⁰⁶Ru was considered as transitional from vibrational U(5) to γ -soft O(6) , no need was found to include the shape-coexisting configurations. In order to provide additional constraints on the model interpretations, we have applied the Advanced Time-Delayed (ATD) βγγ(t) method to measure the level lifetimes of the excited levels in ¹⁰⁶Ru . The new results include the half-lives of T _1/2 = 183(3) ps and 7.5(30)ps for the 2⁺ ₁ and 2⁺ ₂ states, respectively.