Examination of the role of theO14(α,p)F17reaction rate in type-I x-ray bursts
Journal Articles
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
The $^{14}$O($\alpha$,$p$)$^{17}$F reaction is one of the key reactions
involved in the breakout from the hot-CNO cycle to the rp-process in type I
x-ray bursts (XRBs). The resonant properties in the compound nucleus $^{18}$Ne
have been investigated through resonant elastic scattering of $^{17}$F+$p$. The
radioactive $^{17}$F beam was separated by the CNS Radioactive Ion Beam
separator (CRIB) and bombarded a thick H$_2$ gas target at 3.6 MeV/nucleon. The
recoiling light particles were measured by three ${\Delta}$E-E silicon
telescopes at laboratory angles of $\theta$$_{lab}$$\approx$3$^\circ$,
10$^\circ$ and 18$^\circ$, respectively. Five resonances at $E_{x}$=6.15, 6.28,
6.35, 6.85, and 7.05 MeV were observed in the excitation functions, and their
spin-parities have been determined based on an $R$-matrix analysis. In
particular, $J^{\pi}$=1$^-$ was firmly assigned to the 6.15-MeV state which
dominates the thermonuclear $^{14}$O($\alpha$,$p$)$^{17}$F rate below 2 GK. As
well, a possible new excited state in $^{18}$Ne was observed at
$E_{x}$=6.85$\pm$0.11 MeV with tentative $J$=0 assignment. This state could be
the analog state of the 6.880 MeV (0$^{-}$) level in the mirror nucleus
$^{18}$O, or a bandhead state (0$^+$) of the six-particle four-hole (6$p$-4$h$)
band. A new thermonuclear $^{14}$O($\alpha$,$p$)$^{17}$F rate has been
determined, and the astrophysical impact of multiple recent rates has been
examined using an XRB model. Contrary to previous expectations, we find only
modest impact on predicted nuclear energy generation rates from using reaction
rates differing by up to several orders of magnitude.
