High-Statistics Study of theβ+/EC-Decay of110In

A Diaz Varela,G Hackman,S Triambak,C S Sumithrarachchi ,K G Leach ,G A Demand ,J.C Banjay,P Finlay,K.L Green,A B Garnsworthy ,John L Wood ,C E Svensson ,J N Orce ,D S Cross ,P E Garrett ,A A Phillips ,W D Kulp ,E T Rand ,G C Ball ,J Wong,S W Yates

doi:10.1051/epjconf/20146602029

Abstract

A study of the 110In β+/EC decay was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) facility to probe the nuclear structure of 110Cd. The data were collected in scaled-down γ-ray singles, γ − γ coincidence, and γ-electron coincidence mode. The data were sorted and a random-background subtracted γ − γ matrix was created containing a total of 850 million events. We expanded the level scheme of 110Cd significantly by identifying 75 levels under 3.8 MeV, including 12 new ones, and increased the number of previously observed transitions from these levels to 273. The γ-ray branching intensities have been extracted through an analysis of the coincidence intensities. The branching ratios were combined with a reanalysis of lifetimes measurements obtained in an (n, n'γ) reaction with monoenergetic neutrons for the calculation of B(E2) values and these results have lead to the proposal of a γ-soft rotor, or O(6) nucleus, rather than a vibrational, or U(5) pattern for the nature of the low-lying, low-spin levels in 110Cd.

Highlights

The collective Bohr model and the interacting boson model (IBM) have both been used to describe the stable even-even Cd isotopes as examples of spherical vibrational nuclei for decades
Taking into account mixing between the spherical vibrational states and the more-deformed intruder states based on 2p-4h proton excitations, IBM-2 calculations have been successful in reproducing the lowlying level schemes for 110-114 Cd [6]
We have initiated a program of highstatistics β-decay measurements with the 8π spectrometer at the TRIUMF-Isotope Separator and Accelerator (ISAC) radioactive-beam facility

Summary

Introduction

The collective Bohr model and the interacting boson model (IBM) have both been used to describe the stable even-even Cd isotopes as examples of spherical vibrational nuclei for decades. [4] have identified multi-phonon states in the 110 Cd decay scheme indicating vibrational motion. Taking into account mixing between the spherical vibrational states and the more-deformed intruder states based on 2p-4h proton excitations, IBM-2 calculations have been successful in reproducing the lowlying level schemes for 110-114 Cd [6].

Results

Conclusion