Alpha-particles from boron 12: the astrophysical significance

Citation

Cook, Charles William (1957) Alpha-particles from boron 12: the astrophysical significance. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-07012004-103706

Abstract

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Alpha particle emission associated with the [beta]-decay of B12 has been detected and the energy spectrum investigated. These studies show that 1.3 [plus or minus] 0.4 percent of all decays of B12 lead to the second excited state of C12 and 0.13 [plus or minus] 0.04 percent of the decays lead to what is most probably a broad state of higher excitation in C12. The most probable-spin and parity assignments for the second excited state appear to be [...], and analysis of the alpha-spectrum yields [...]kev, corresponding to an excitation energy in [...] Mev. A new determination of the disintegration energy of Be8 yields [...] kev and hence [...] kev. It is concluded from the general principle of reversibility of nuclear reactions, that the second excited state of C12 as predicted by Hoyle is of a suitable character to act as a stellar thermal resonance in the Salpeter process, [...]; [...] under conditions expected in red giant stars. The high-energy spectrum is consistent with a broad level peaking at an excitation energy 10.1 [plus or minus] 0.2 Mev in C12 and having a width at half maximum of [...]. The most probable spinand parity assignments for this level are [...] although [...] cannot definitely be excluded; for [...], the width is approximately the Wigner limit.

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