1. First application of Markov Chain Monte Carlo-based Bayesian data analysis to the Doppler-Shift Attenuation Method
- Author
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Sun, L. J., Fry, C., Davids, B., Esker, N., Wrede, C., Alcorta, M., Bhattacharjee, S., Bowry, M., Brown, B. A., Budner, T., Caballero-Folch, R., Evitts, L., Friedman, M., Garnsworthy, A. B., Glassman, B. E., Hackman, G., Henderson, J., Kirsebom, O. S., Kurkjian, A., Lighthall, J., Machule, P., Measures, J., Moukaddam, M., Park, J., Pearson, C., Pérez-Loureiro, D., Ruiz, C., Ruotsalainen, P., Smallcombe, J., Smith, J. K., Southall, D., Surbrook, J., Williams, M., and Weghorn, L. E.
- Subjects
Nuclear and High Energy Physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Nuclear Experiment (nucl-ex) ,Nuclear Experiment - Abstract
Motivated primarily by the large uncertainties in the thermonuclear rate of the $^{30}$P(p,γ)31S reaction that limit our understanding of classical novae, we carried out lifetime measurements of $^{31}$S excited states using the Doppler Shift Lifetimes (DSL2) facility at the TRIUMF Isotope Separator and Accelerator (ISAC-II) facility. The $^{31}$S excited states were populated by the $^{3}$He(32S,α)31S reaction. The deexcitation γ rays were detected by a clover-type high-purity germanium detector in coincidence with the α particles detected by a silicon detector telescope. We have applied modern Markov chain Monte Carlo-based Bayesian statistical techniques to perform lineshape analyses of Doppler-shift attenuation method γ-ray data for the first time. We have determined the lifetimes of the two lowest-lying $^{31}$S excited states. First experimental upper limits on the lifetimes of four higher-lying states have been obtained. The experimental results were compared to shell-model calculations using five universal sd-shell Hamiltonians. Evidence for γ rays originating from the astrophysically important Jπ=3/2+, 260-keV $^{30}$P(p,γ)31S resonance with an excitation energy of Ex=6390.2(7) keV in $^{31}$S has also been observed, although strong constraints on the lifetime will require better statistics.
- Published
- 2022