One proton, two proton, and alpha emission from 14o+alpha resonance interactions

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2009-05-15

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Abstract

In this dissertation, proton, two proton, and emission from the 14O + a interactions were studied with the modified thick target inverse kinematics approach. The radioactive beam was obtained by using resonances in the 14N(p, n)14O reaction. The 14O was > 99% pure. By using a beam analysis system, the contaminant-tobeam ratio was suppressed further to the 10?4 level. This makes the 14O beam at TAMU one of the best available. For the 14O(a, 2p) interaction, it was found that the resonance excited states in 18Ne are populated, and most of them decay sequentially to the ground state of 16O, i.e. 18Ne* ! 17F* + p ! 16O + p + p. Two proton events corresponding to the excited state of 18Ne*(8.45MeV), were found to have strong 2p correlation, which is the fingerprint of 2He-decay. Several models were used to explain this decay process, and evidence suggests that this state decays by 2He-emission. By measuring the Time-Of-Flight for protons through the thick target, the location of 14O(, p) reactions occurring at different places in the helium gas target were identified. With this information, we were able to measure a spectrum of protons corresponding to the population of 17F particle stable states in the 14O(a, p)17F reaction. This method provides a new way to measure astrophysically important reactions which involve radioactive nuclei and a particles. By analyzing elastic scattering of 14O and 14C on 4He, a-cluster states in 18Ne* and 18O* were found. Some a-cluster states in 18Ne* were found for the first time.

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