Date of Award

Spring 2012

Degree Type

Thesis

Degree Name

Master of Science (MSc)

Department

Physics and Astronomy

Supervisor

Alan A. Chen

Co-Supervisor

Donald Sprung

Language

English

Committee Member

Reza Nejat

Abstract

The astrophysical ³⁰P(p,γ)³¹S reaction rate is a key quantity used in both classical nova and type I X-ray burst models that predict isotopic abundances produced during nucleosynthesis in the outburst. Currently, uncertainties in ³¹S structure parameters lead to a variation in the reaction rate by a factor of 20 at nova temperatures causing predicted isotopic abundance ratios in the Si-Ar mass region to vary by factors of up to 4. The ³⁰P(p,γ)³¹S reaction rate can be determined indirectly by measuring transfer reactions populating excited states in ³¹S. Nuclear structure information for ³¹S resonant states above the proton threshold of 6131 keV and within the Gamow window that contribute most significantly to the reaction rate can be used to re-evaluate the rate for nova and type I X-ray burst temperatures and reduce current uncertainties. We have performed an experiment in order to study the level structure of ³¹S via the ³²S(d,t)³¹S single-nucleon transfer reaction using the MP tandem accelerator and Q3D magnetic spectrograph at MLL in Munich, Germany. Excited states of ³¹S in the 6-7 MeV region were observed and spin-parity constraints have been suggested. In this work we describe the experimental setup, data analysis and results for both experiments and provide recommendations for further investigation of the ³⁰P(p,γ)³¹S astrophysical reaction rate.

Recommended Citation

Irvine, Dan T., "A Study of the Astrophysically Important States of 31S via the 32S(d,t)31S Reaction" (2012). Open Access Dissertations and Theses. Paper 6848.
http://digitalcommons.mcmaster.ca/opendissertations/6848

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