Seminar - Oliver Kirsebom: 'Gamma rays from novae'
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Gamma rays from novae
Novae are thermonuclear explosions that take place on the surface of white dwarf stars with a close companion star. With a handful detected in the Galaxy every year, they constitute a very common phenomenon and contribute to the enrichment of the interstellar medium. One of the isotopes thought to be produced in novae, Na-22, emits a characteristic gamma ray which, if observed, would provide a crucial test of our current understanding of novae. Precise calculation of the expected gamma-ray flux requires precise knowledge of the rates of the nuclear reactions that create and destroy Na-22. Unfortunately, one of the most important rates, namely, that of radiative proton capture on Na-22, is uncertain by a factor of 2-3. In an attempt to reduce this uncertainty, we have measured the lifetime of a certain resonance in the compound nucleus, Mg-23, that is known to dominate the rate. In my talk, I will describe the experiment and present preliminary results.