ScholarWorks@성균관대학교

초록

Recent sensitivity studies have shown that nucleosynthesis in Core-collapse supernovae (CCSNe) is significantly influenced by the N-13(alpha, p)O-16 reaction rate. However, the reaction rate at stellar temperatures (up to 4 GK) remains poorly constrained, primarily due to the limited knowledge of the decay properties of relevant F-17 resonances above the a threshold at 5.819 MeV. To improve these constraints, we performed the F-19(p, t)F-17 transfer reaction experiment aimed at refining the N-13(alpha, p)O-16 rate. The experiment was performed at the tandem accelerator facility of the Japan Atomic Energy Agency using 30.5-MeV proton beams incident on CaF2 targets backed with gold. Recoiling tritons from the F-19(p, t)F-17 reaction were detected with segmented silicon detector arrays. The triton energy spectra revealed several low-lying F-17 states, and angular distributions were analyzed using finite-range Distorted Wave Born Approximation (DWBA) calculations with multiple optical-model parameter sets. Proton and alpha decay channels associated with specific F-17 resonances were clearly identified, which will allow us to determine the branching ratios. The optimized optical potentials and measured decay yields will provide direct experimental constraints on the alpha- and proton-partial widths (Gamma(a), Gamma(p)) of F-17 levels in the Gamow window (E-x = 6-9.5MeV). The resulting resonance parameters will enable a more reliable determination of the N-13(alpha, p)O-16 reaction rate, thereby reducing its current uncertainty in CCSNe nucleosynthesis models.

키워드