Abstract
22Ne(α,n)25Mg is one of the main neutron sources of the s process. 22Ne is produced by the 14N(α, γ)18F(β+)18O(α, γ)22Ne reaction chain in the helium burning, thus, the production rate of 22Ne is dominated by 14N(α,γ)18F and 18O(α,γ)22Ne. At the astrophysical relevant temperatures, the 18O(α,γ)22Ne reaction rates are determined by several low-energy resonances. In this work, the 18O(α,γ)22Ne reaction was measured at the 400 kV accelerator of Jinping Underground Nuclear Astrophysics experiment (JUNA). The γ-ray yields of the resonances between 470 to 770 keV were obtained.
Highlights
About half of the heavy elements above Fe in our universe are synthesised by the slow neutron capture process (s-process) drove by the neutron from the 13C(α, n)16O and 22Ne(α, n)25Mg reactions [1, 2]. 22Ne(α, n)25Mg is considered to be the main neutron source of the s-process during convective core helium burning and convective shell carbon burning in massive stars [2], in which the 22Ne is produced through the 14N(α,γ)18F(β+υ)18O(α,γ)22Ne reaction chain in the early phase of core helium burning
Dababneh et al [5] investigated the 470 keV resonance by a coincidence method for the first time, in which the 470 keV resonance strength was derived by a presumptive branching ratio
The 18O(α,γ)22Ne reaction needs to be further measured in an underground laboratory with low background to reduce the uncertainties of the low-energy resonance strengths and improve the precision of the reaction rates, which is of great significance to the nucleosynthesis study of s process
Summary
About half of the heavy elements above Fe in our universe are synthesised by the slow neutron capture process (s-process) drove by the neutron from the 13C(α, n)16O and 22Ne(α, n)25Mg reactions [1, 2]. 22Ne(α, n)25Mg is considered to be the main neutron source of the s-process during convective core helium burning and convective shell carbon burning in massive stars [2], in which the 22Ne is produced through the 14N(α,γ)18F(β+υ)18O(α,γ)22Ne reaction chain in the early phase of core helium burning. The 14N(α,γ)18F and 18O(α,γ)22Ne reaction rates are the key parameters in the calculation of 22Ne abundance and the subsequent 22Ne(α, n)25Mg neutron production rate, which need to be determined precisely. Vogelaar et al [4] measured the precise resonance energies, the primary γ-ray branching ratios, and the resonance strengths of the 662, 750, and 770 keV resonances. Dababneh et al [5] investigated the 470 keV resonance by a coincidence method for the first time, in which the 470 keV resonance strength was derived by a presumptive branching ratio. The 18O(α,γ)22Ne reaction needs to be further measured in an underground laboratory with low background to reduce the uncertainties of the low-energy resonance strengths and improve the precision of the reaction rates, which is of great significance to the nucleosynthesis study of s process
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call