Investigating the excitation spectrum of [superscript 8]He from inelastic scattering with deuterons

Abstract

Rare isotopes are nuclei with very short half-lives and can have a large asymmetry of neutrons to protons. These isotopes can have unusual structures such as halos that can exhibit a phenomenon known as a Soft Dipole Resonance (SDR). One rare isotope of interest is 8-Helium (⁸He) which is the most neutron-rich bound nucleus currently known, with a neutron to proton ratio of 3. In previous investigations of ⁸He two excited states (2⁺ and 1⁺) were observed with drastically conflicting reportson their locations. The inconsistent reports on the 2⁺ state, in particular, have been postulated to be due to the excited state being mixed with a low-lying SDR state. Through an experiment conducted at the IRIS facility located at TRIUMF, Canada’s particle acceleration center, the excited spectrum of ⁸He has been investigated. The goal of this study is to get additional measurements on the excited states of ⁸He as well as explore the possibility of the 2⁺ state being mixed with a SDR. In this thesis,I will outline the experimental set up and the data analysis to determine the Q-value spectrum of ⁸He from the ⁸He(d,d′) ⁸He^∗ reaction.