The reaction rate for the destruction of fluorine in AGB stars

Thermonuclear rate for theF19(α,p)Ugalde1, Azuma2, Couture3 et al. 2008Phys. Rev. CSelf Cite294331View full textAdd to dashboardCite

“…The differential cross section of the 19 F(α, p) 22 Ne reaction was determined relative to the differential cross section for elastic scattering measured at 160 • . It has been shown by Huang-sheng et al [22] and by Cseh et al [23] that below E lab = 2.5 MeV the elastic scattering of 4 He on 19 F follows the Rutherford law,…”

“…This study included the direct measurement of the 19 F(α, p) 22 Ne reaction by detecting both p 0 and p 1 protons (see Refs. [19,20]) as well as the additional measurement of the p 1 channel via the detection of the γ -ray transition [21] from the first excited state (2 + ) to the ground state (0 + ) of 22 Ne (see Fig. 1).…”

“…The 19 F transmission targets were prepared by evaporating 10 µg/cm 2 of CaF 2 on 40-µg/cm 2 natural carbon substrates, mounted on aluminum frames. The target was placed with the evaporated material facing the beam on a ladder attached to a rotating rod at the center of the scattering chamber.…”

“…This second possibility does not produce fluorine. The alternative 18 O(p, α) 15 N(α, γ ) 19 F capture reaction is the main fluorine production link in this scenario. The abundance of 15 N depends sensitively on the hydrogen abundance in the intershell region.…”

The thermonuclear rate for the 19F(a,p)22Ne reaction at stellar temperatures

“…α + 0.0 (MeV) 23 Na FIG. 1: Energy level scheme for the 19 F(α,p) 22 Ne reaction. The entrance channel (α+ 19 F) has a threshold of 10.47 MeV with respect to the ground state of 23 Na.…”