Frank Blank

Doctoral Dissertation Announcement

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Candidate: Ravin S. T. Kodikara

Degree of: Doctor of Philosophy

Department: Physics

Title: Proton Capture Reactions and Network Calculations on 46Ti, 64Zn, 114Sn and 116Sn Relevant to the rp-Process

Committee:
Dr. Michael Famiano, Chair
Dr. Dean Halderson
Dr. Paul Pancella
Dr. Pnina Ari-Gur

Date: Thursday, November 11, 2010 3:30 p.m. to 5:30 p.m.
2202 Everett Tower

Abstract:
The rp-process makes an important contribution to the stellar nucleosynthesis by producing many of the light proton rich nuclei. Successive proton captures on seed nuclei followed by occasional β-decays and electron captures are the key features of this mechanism. For a detailed rp-process analysis, proton capture cross sections and reaction rates are essential. However, the lack of experimental data forces the researcher to largely depend on statistical model predictions.
This dissertation research is an attempt to investigate the proton captures of four particular nuclides: 46Ti, 64Zn, 114Sn and 116Sn. At Western Michigan University Van de Graaff accelerator facility, target nuclides were irradiated using a proton beam with energy ranging from 1MeV to 3.7MeV. The resulting gamma radiation was detected by HPGe detectors at a dedicated counting station.
Proton capture cross sections and astrophysical S-factors were measured and a good agreement between the experimental S-factor results and the NON-SMOKER predictions was observed, especially in the higher proton energies. With respect to reaction rates, NON-SMOKER predictions were much closer to the experimental results, while MOST code predictions were slightly higher than the actual reaction rates.
Furthermore, a reaction network model code (GAMBLER) was used to simulate the stellar rp-process and photodisintegration reaction. Abundance distributions of 47Ti, 47V, 65Zn, 65Ga, 115Sn, 115Sb, 117Sn and 117Sb were calculated and compared with theoretical predictions. Comparison of experimental abundance results and theoretical predictions for above elements revealed sufficient correlation between them and proved the applicability of the network code in rp-process and photodisintegration simulations.