<sup>30</sup>P(p,γ)<sup>31</sup>S reaction rate in novae: lifetimes of <sup>31</sup>S states
ORAL
Abstract
In classical novae, the 30P(p,γ)31S reaction acts as a nucleosynthesis bottleneck in the flow of material to heavier masses. The thermonuclear rate of the 30P(p,γ)31S reaction is dominated by proton capture into narrow resonances just above the proton-emission threshold in 31S. To constrain the resonance strengths, we carried out lifetime measurements of the 31S resonances using the Doppler Shift Attenuation Method. The experiment was performed using the Doppler Shift Lifetimes (DSL) facility at the TRIUMF-ISAC-II facility. The 31S states were populated by the 3He(32S,α)31S reaction. The deexcitation γ rays were detected by Clover detectors in coincidence with the α particles detected by a Si telescope. We applied a Bayesian parameter estimation method and obtained the lifetimes for the two lowest 31S excited states. The upper limits of the lifetimes for five higher-lying states were obtained for the first time. The γ rays originating from a key 3/2+ resonance were observed but with limited statistics. To further improve the sensitivity, an upgrade of the DSL facility is currently underway.
*This work was supported by the U.S. National Science Foundation under Grants Nos. PHY-1102511 and PHY-1565546, and the U.S. Department of Energy, Office of Science, under Award No. DE-SC0016052.
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Presenters
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Lijie Sun
- National Superconducting Cyclotron Labor
- Michigan State University