The excitation energy of the low-lying isomeric state in 102Y

Abstract

A key part of understanding nuclear structure is understanding the mechanisms that drive deformation. Isotopes in the A = 100 region undergo a rapid shape change at N = 59, yet the reason for this is not well understood. Many nuclei in this region have isomeric states which require additional investigation in regards to their structure. An example of this is 102Y which has two β −-decaying states, a low-spin state and a high-spin state, however it is not known which of these states is the ground state; this is because they have similar half-lives of 300(10)- and 360(40) ms respectively and a small energy difference, thus making it difficult to distinguish between them. In this work, an experiment was conducted using the JYFLTRAP double Penning trap system at the University of Jyvaskyla, Finland, to separate the two states and measure their energy separation. Following an optimisation of ion transport within the post-trap setup, the nuclei of interest 102Y was produced via proton-induced fission of 238U and the Phase-Imaging Ion-Cyclotron-Resonance method used to measure the excitation energy of the isomeric state in 102Y. A statistical analysis of the data indicates an excitation energy of 12.3(16) keV for the isomeric state in 102Y with the high-spin state being the ground state. Analysis of a supplementary data set obtained at the Radioactive Isotope Beam Factory, RIKEN, Japan, allowed for the structure of 102Y to be studied by observing the γ-rays emitted following the β −-decay of 102Sr, with the aim of searching for a level at 12.3(16) keV. No such level has been found, however the level scheme of 102Y has been extended via the identification of 7 new tentative γ-ray transitions.

Date of Award	Jul 2022
Original language	English
Awarding Institution	University of Brighton
Supervisor	Alison Bruce (Supervisor) & Zsolt Podolyák (Supervisor)