Search for Shape Coexistence Signatures in ¹⁰⁰Ru using Thermal Neutron Capture Reaction

Recent studies within the Zr (Z=40) - Sn (Z=50) region have shown several nuclei to possess shape coexistence which occurs when states existing in a narrow energy gap within the same nucleus possess distinct shapes. In the Ru (Z=44) isotopes, strong evidence has emerged for shape coexistence within ¹⁰²Ru and ¹⁰⁴Ru from Coulomb excitation [1,2], and it was suggested in ⁹⁸Ru and ¹⁰⁰Ru as well [3]. In order to explore shape coexistence in ¹⁰⁰Ru, and also probe possible vibrational motion, key mixing ratios and the observation of low-energy, and hence often very weak intensity, transitions between non-yrast states are required. This study of ¹⁰⁰Ru presented in this work aims to extract precise mixing ratios, unobserved weak g-ray transitions and transition probabilities to resolve its structural behaviour. We used the thermal neutron capture reaction, ⁹⁹Ru(n,g)¹⁰⁰Ru, carried out at the Institut Laue-Langevin in Grenoble, France [4]. The g-ray transitions depopulating the excited states in ¹⁰⁰Ru were detected by the FIPPS array consisting of two sets of eight clover-type hyper-pure Germanium detectors. A total of 106 combined angle pairs permitted precise g-g angular correlations analysis. Preliminary results from the current analysis will be presented with emphasis on the mixing ratios of the g-ray transitions.