Breakout From The Hot Cno Cycle Via The Ne-18(Alpha,P)Na-21 Reaction. Ii. Extended Energy Range E-C.M.Similar To 1.7-2.9 Mev

We have extended the experiment reported in Bradfield-Smith [Phys. Rev. C 59, 3402 (1999)] concerning the Ne-18(alpha,p)Na-21 reaction, which is of importance to nuclear astrophysics. This study covered an energy region similar to1.7-2.9 MeV in the center of mass frame of the Ne-18+alpha system. A change in the detector geometry resulted in an increase in the detection efficiency and significantly reduced the proton background that hindered the previous measurement. A direct measurement of the energy loss of the Ne-18 beam, as it passed through He gas, was undertaken to reduce a major source of uncertainty in the determination of the stellar reaction rate. Eight states have been identified in the compound nucleus, Mg-22. These resonances were used to calculate an enhanced stellar reaction rate which shows good agreement with theoretical predictions [Gorres, Wiescher, and Thielemann, Phys. Rev. C 51, 392 (1995)] at and above a temperature of 1.5 GK. The impact of this enhanced stellar reaction rate upon the nucleosynthesis that occurs during the peak phase of an x-ray burst has been investigated.