# 2015 CAP Congress / Congrès de l'ACP 2015

13-19 June 2015
University of Alberta
America/Edmonton timezone
Welcome to the 2015 CAP Congress! / Bienvenue au congrès de l'ACP 2015!

## New decay modes of the high-spin isomer of $^{124}$Cs

16 Jun 2015, 15:00
15m
CCIS L1-140 (University of Alberta)

### CCIS L1-140

#### University of Alberta

Oral (Student, In Competition) / Orale (Étudiant(e), inscrit à la compétition) Nuclear Physics / Physique nucléaire (DNP-DPN)

### Description

As part of a broader program to study the evolution of collectivity in the even-even nuclei above tin, a series of $\beta$-decay measurements of the odd-odd Cs isotopes into the even-even Xe isotopes, specifically $^{122,124,126}$Xe, have been made utilizing the 8$\pi$ spectrometer at TRIUMF-ISAC. The 8$\pi$ spectrometer consisted of 20 Compton-suppressed high-purity germanium (HPGe) detectors and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) conversion electron detectors. The decay of $^{124}$Cs to $^{124}$Xe is the first measurement to be fully analyzed. A very high-statistics data set was collected and the $\gamma\gamma$ coincidence data were analyzed, greatly extending the $^{124}$Xe level scheme. Several weak $\it{E2}$ transitions into excited 0$^+$ states in $^{124}$Xe were observed. The $\it{B(E2)}$ transition strengths of such low-spin transitions are very important in determining collective properties, which are currently poorly characterized in the region of the neutron-deficient xenon isotopes. A new $\beta^+$/EC-decay branch from a high-spin isomeric state of $^{124}$Cs has been observed for the first time. Decay of the isomer ($J^\pi$ = (7)$^+$, $T_{1/2}$ = 6.3(2) s) is seen to populate high-spin states in the $^{124}$Xe daughter nucleus that are otherwise inaccessible through the $\beta$-decay of the 1$^+$ $^{124}$Cs ground state. Combining $\gamma\gamma$ as well as $\gamma$-electron coincidence data, several new transitions in the isomeric decay of the (7)$^+$ state have been observed. The characterization of the new $\beta$-decay branch and the isomeric decay of the high-spin state will be presented.