Nuclear astrophysics with RIBs at Oak Ridge National Laboratory

摘要

The Daresbury Recoil Separator (DRS) and Silicon Detector Array (SIDAR) have been installed at Oak Ridge National Laboratory (ORNL) to perform measurements of reaction cross sections of astrophysical interest using radioactive ions beams (RIBs). For example radioactive (sup 17)F beams will be used to determine the (sup 14)O((alpha),p)(sup 17)F and (sup 17)F(p,(gamma)) (sup 18)Ne stellar reaction rates--both of which are important reactions in the Hot-CNO cycle. The first reactions studied will be (sup 1)H((sup 17)F,p)(sup 17) F and (sup 1)H((sup 17)F,(alpha))(sup 14)O. These experiments will require (sup 17)F beams with intensities of 10(sup 4)--10(sup 6) ions per second in conjunction with the SIDAR. The (sup 1)H((sup 17)F,p)(sup 17)F reaction will be used to probe resonances in (sup 18)Ne which contribute to the (sup 17)F(p, (gamma))(sup 18)Ne stellar reaction rate, while (sup 1)H((sup 17)F,(alpha))(sup 14)O will be used to determine the stellar reaction rate of the inverse reaction (sup 14)O((alpha),p)(sup 17)F. In preparation for these experiments, measurements have been made of the (sup 1)H((sup 17)O,p)(sup 17)O and (sup 1) H((sup 17)O,(alpha))(sup 14)N reaction cross sections. When higher beam currents of (sup 17)F become available, a direct measurement of the (sup 1) H((sup 17)F, (sup 18)Ne) resonance strength will be made using the DRS. To test the performance of the DRS for measuring capture reaction cross sections, the well-known (sup 1)H((sup 12)C, (sup 13)N) cross section has been measured at an energy similar to those proposed for radioactive beam experiments. Results from these stable beam experiments are discussed.