Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method

• Main Author: Sowazi, Khanyisa
• Other Authors: Wiedeking, Mathis
• Language: en
• Published: University of the Western Cape 2019
• Subjects: Banana Spectra; Branching Ratio; Brink-axel hypothesis; Low Energy Enhancement; Multipolarity; Nuclear level density; Particle- coincidence; Particle ray tracing; Primary rays; Quasi-continuum; Quasi strength; Ratio Method; Gamma-ray strength function (GSF)
• Online Access: http://hdl.handle.net/11394/6725

>Magister Scientiae - MSc === An increasing number of measurements reveal the presence of a low-energy enhancement in the gamma-ray strength function (GSF). The GSF, which is the ability of nuclei to absorb or emit rays, provides insight into the statistical properties of atomic nuclei. For this project the GSF was studied for 74Ge which was populated in the reaction 74Ge(p,p')74Ge* at a beam energy of 18 MeV. The data were collected with the STARS-LIBERACE array at Lawrence Berkeley National Laboratory. Silicon detector telescopes were used for particle identi cation and rays in coincidence were detected with 5 clover-type high-purity germanium detectors. Through the analysis particle- - coincidence events were constructed. These events, together with well-known energy levels, were used to identify primary rays from the quasicontinuum. Primary rays from a broad excitation energy region, which decay to six 2+ states could be identi ed. These states and the associated primary rays are used to measure the GSF for 74Ge with the Ratio Method [1], which entails taking ratios of e ciency-corrected primary -ray intensities from the quasicontinuum. Results from the analysis of the data and focus on the existence of the low-energy enhancement in 74Ge will be discussed. The results are further discussed in the context of other work done on 74Ge using the ( , ') [2], (3He,3He') [3] and ( , ') [4] reactions.