Thesis (PhD (Physics))--University of Stellenbosch, 2006. / This thesis is devoted to a study of the 93Nb( p r ,3He) and 59Co( p r ,3He) reactions at incident
energies of 100 MeV, 130 MeV and 160 MeV. Double differential cross sections and
analysing power distributions were measured from a threshold of ~30 MeV up to the
kinematic maximum and at scattering angles between 15º and 120º. The experimental data
were compared with theoretical calculations done by combining a statistical multistep theory
with a deuteron pickup mechanism in the final stage. The contribution of the first three steps
towards the total double differential cross section and analysing power was assessed.
The theory described the experimental double differential cross section and analysing power
data reasonably well over all incident and scattered energies and for both target nuclei. As
the incident energy was increased, the characteristics of the reaction mechanism also
remained consistent. Thus the results supported the underlying multistep-pickup theory. The
two target nuclei demonstrated similar responses, suggesting these two share the same basic
reaction mechanism.
The total double differential cross section for the reaction dropped with an increase in
incident energy. At a fixed emission energy, near the maximum allowed value, the slope of
the double differential cross section increased with an increase in incident energy, resulting in
the dominance of forward peaked reactions at higher incident energies.
The sensitivity of analysing power to the multistep part of the reaction was valuable to the
study. Forward-peaked contributions that were associated with single step direct reactions
resulted in large analysing power values at small scattering angles, and values dropped to
around zero at large angles. The analysing power also appeared to decrease to values
approximating zero as the incident energy was increased to 160 MeV. Furthermore, this
study also confirmed the dominance of higher step mechanisms at high excitation energies,
irrespective of incident energy. In general the results were in agreement with the predicted
properties of the assumed reaction mechanism at all incident and emission energies, which
inspires confidence that the theoretical interpretation is likely to be correct.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/1307 |
| Date | 12 1900 |
| Creators | Bezuidenhout, Jacques |
| Contributors | Cowley, A. A., University of Stellenbosch. Faculty of Science. Dept. of Physics. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 2166205 bytes, application/pdf |
| Rights | University of Stellenbosch |
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