Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method
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Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Western Cape
Abstract
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.
Description
>Magister Scientiae - MSc
Keywords
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)