In this thesis, the first-order and higher-order interferences on the total (Coulomb+nuclear),
Coulomb and nuclear breakup cross sections in the 15C+208Pb, 11Be+208Pb breakup reactions
are first studied at 68 MeV/u incident energy. It is shown that the first-order
interference reduces by more than 60% the total breakup cross sections, by less than 3%
the Coulomb breakup cross sections and by more than 85% the nuclear breakup cross sections,
for both reactions. On the other hand, the high-order interference is found to reduce
by less than 9% the total breakup cross section, less than 1% the Coulomb breakup cross
section and less than 7% the nuclear breakup cross section for the 15C+208Pb reaction.
For the 11Be+208Pb reaction however, the high-order interference reduces by less than 7%
the total breakup cross section, by less than 1% the Coulomb breakup cross section and by
less than 4% the nuclear breakup cross section. It is finally shown that even at first-order,
the incoherent sum of the nuclear breakup cross sections is more important than the incoherent
sum of the Coulomb breakup cross sections for the two reactions. The role of the
diagonal and off-diagonal continuum-continuum couplings on total, Coulomb and nuclear
breakup cross sections is also investigated for the 8B+58Ni, 8B+208Pb and 19C+208Pb at
29.3, 170.3 MeV and 1273 MeV incident energies respectively. Qualitatively, we found
that, the diagonal continuum-continuum couplings are responsible for the large reduction
of the differential total and nuclear breakup cross sections at backward angles. At forward
angles, this reduction is due to the off-diagonal continuum-continuum couplings. In the
absence of these couplings, the nuclear breakup is the more dominant process, while when they are included, the Coulomb breakup becomes dominant. This shows that, the nuclear
breakup is more affected by the continuum-continuum couplings than its Coulomb
counterpart. Quantitatively, we found that, the off-diagonal countinuum-countinuum
couplings reduce by 13.39%, 12.71% and 11.11% the total breakup cross sections for the
8B+58Ni, 8B+208Pb and 19C+208Pb reactions, respectively. / Physics / D. Phil. (Physics)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:unisa/oai:uir.unisa.ac.za:10500/20711 |
| Date | 06 1900 |
| Creators | Mukeru, Bahati |
| Contributors | Lekala, M. L., Denikin, A. S. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 1 online resource (xiv, 130 leaves) : illustrations |
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