Lifetimes of excited states in triaxially deformed 107Tc and 109,111,113Rh

T. W. Hagen; A. Görgen; W. Korten; L. Grente; M. -D. Salsac; F. Farget; T. Braunroth; B. Bruyneel; I. Celikovic; E. Clément; G. de France; O. Delaune; A. Dewald; A. Dijon; M. Hackstein; B. Jacquot; J. Litzinger; J. Ljungvall; C. Louchart; C. Michelagnoli; D. R. Napoli; F. Recchia; W. Rother; E. Sahin; S. Siem; B. Sulignano; Ch. Theisen; J. J. Valiente-Dobon

doi:10.1140/epja/i2018-12482-9

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A (2018) 54: 50
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

T. W. Hagen¹, A. Görgen¹^*, W. Korten², L. Grente², M. -D. Salsac², F. Farget³, T. Braunroth⁴, B. Bruyneel², I. Celikovic³^,5, E. Clément³, G. de France³, O. Delaune³, A. Dewald⁴, A. Dijon³, M. Hackstein⁴, B. Jacquot³, J. Litzinger⁴, J. Ljungvall⁶, C. Louchart², C. Michelagnoli⁷, D. R. Napoli⁷, F. Recchia⁸^,9, W. Rother⁴, E. Sahin¹^,7, S. Siem¹, B. Sulignano², Ch. Theisen² and J. J. Valiente-Dobon⁷

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

Abstract

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.