Eur. Phys. J. A (2005) 26: 153-157
https://doi.org/10.1140/epja/i2005-10174-3

Original Article

Lifetime measurement in ⁷⁴Kr and ⁷⁶Kr

¹ DAPNIA/SPhN, CEA Saclay, F-91191, Gif-sur-Yvette Cedex, France
² Institut für Kernphysik, Universität zu Köln, D-50937, Köln, Germany
³ INFN-Laboratori Nazionali di Legnaro, I-35020, Legnaro (Padova), Italy
⁴ Dipartimento di Fisica, Università di Padova and INFN Sezione di Padova, I-35131, Padova, Italy

Received: 24 October 2005
Accepted: 18 November 2005
Published online: 1 December 2005

Abstract

Lifetimes of excited states in the ground-state bands of ⁷⁴Kr and ⁷⁶Kr were measured using the recoil-distance Doppler-shift and the differential decay curve methods. The states were populated in the ⁴⁰Ca(⁴⁰Ca, α2p) and ⁴⁰Ca(⁴⁰Ca, 4p) reactions. Gamma rays were detected with the GASP array which was coupled to the Cologne Plunger device. The results resolve discrepancies between earlier lifetime measurements and a recent Coulomb excitation experiment. Experimental transition rates are compared to theoretical calculations. The results support a strong mixing between prolate and oblate configurations for the low-spin states, and represent an important basis for the interpretation and understanding of the shape coexistence phenomenon in this mass region.