Study of proton resonances in ¹⁸Ne via resonant elastic scattering of ¹⁷F + p and its astrophysical implication in the stellar reaction of ¹⁴O(α, p)¹⁷F

The stellar O-14(alpha, p) F-17 reaction is thought to be one of the most important breakout reactions from the Hot CNO cycles into the rp-process in Type I X-ray bursters. In the present work, the properties of proton resonances in Ne-18 have been investigated efficiently by utilizing a technique of proton resonant elastic scattering with a F-17 radioactive-ion (RI) beam and a thick proton target. A 4.22MeV/nucleon F-17 RI beam, which was produced via a projectile-fragmentation reaction and experiencing a series of energy degradation, was separated by a Radioactive Ion Beam Line in Lanzhou (RIBLL) and bombarded a (CH2)(n) target. Energy spectra of the recoiled protons were measured by two sets of Delta E-E silicon telescope at center-of-mass scattering angles of theta(c.m.) approximate to 175 degrees +/- 5 degrees, theta(c.m.) approximate to 152 degrees +/- 8 degrees, respectively. Several proton resonances in Ne-18 were observed, and their resonant parameters have been determined by an R-matrix analysis of the differential cross-sections. A doublet structure around 7.10MeV has been identified and thought to be one state at 7.05MeV (2(+)) and another one at 7.12MeV (4(+)). The presently calculated total reaction rates of O-14(alpha, p) F-17 are, at least, a factor of 1.2 similar to 1.9 larger than the previous ones in a temperature region of 1.7 similar to 3.0 GK mainly owing to the contribution from the 7.05MeV (2(+)) state. This result implies that this breakout reaction may play a more important role than previously expected.