Deep underground laboratory measurement of ${}^{13}$C($\alpha$,$n$)${}^{16}$O in the Gamow windows of the $s$- and $i$-processes

Abstract

The ${}^{13}$C($\alpha$,$n$)${}^{16}$O reaction is the main neutron source for the slow-neutron-capture (s-) process in Asymptotic Giant Branch stars and for the intermediate (i-) process. Direct measurements at astrophysical energies in above-ground laboratories are hindered by the extremely small cross sections and vast cosmic-ray induced background. We performed the first consistent direct measurement in the range of $E_{c.m.}=$0.24 MeV to 1.9 MeV using the accelerators at the China Jinping Underground Laboratory (CJPL) and Sichuan University. Our measurement covers almost the entire i-process Gamow window in which the large uncertainty of the previous experiments has been reduced from 60\% down to 15\%, eliminates the large systematic uncertainty in the extrapolation arising from the inconsistency of existing data sets, and provides a more reliable reaction rate for the studies of the s- and i-processes along with the first direct determination of the alpha strength for the near-threshold state.

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• Concurrent application of ANC and THM to assess the ${}^{13}\mathrm{C}(\alpha ,n{)}^{16}\mathrm{O}$ absolute cross section at astrophysical energies and possible consequences for neutron production in low-mass AGB stars
• New $\alpha$ ANC measurement of the 1/2${}^{+}$ state in ${}^{17}$O at 6.356 MeV, that dominates the ${}^{13}$C($\alpha$,n)${}^{16}$O reaction rate at temperatures relevant for the s-process
• Spectroscopic factors, overlaps, and isospin symmetry from an $R$-matrix point of view

Cited by in corpus (8)

• The s Process and Beyond
• Improved $S$-factor of the ${}^{12}$C(p,$\gamma$)${}^{13}$N reaction at $E=$320-620~keV and the 422~keV resonance
• Underground laboratory JUNA shedding light on stellar nucleosynthesis
• Detectors and Shieldings: Past and Future at LUNA
• Status and future directions for direct cross-section measurements of the 13C(a,n)16O reaction for astrophysics
• A prototype neutron-detector array for future deep-underground s-process studies
• Impact of the latest 22Ne+α reaction rates on nucleosynthesis in massive stars and galactic chemical evolution
• Stellar ${\beta }^{-}$-decay rate of ${}^{63}$Ni and its impact on the $s$-process nucleosynthesis in massive stars