Nuclear astrophysics with RIBs at oak ridge national laboratory

摘要

SThe Daresbury Recoil separator (DRS) and Silicon Detertor Array (SIDAR) have been installed at Oak Ridge National Laboratory (ORNL) to perform measurements of reaction cross sections of astrophysical interest using radioactive ion beams (RIBs). For example radioactive ~(17)F beams will be used to determine the ~(14)O( alpah , p)~(17)F and ~(17)F(p, gamma )~(18)Ne stellar reaction rates-both of which are important reactions in the Hot-CNO cycle. The first reactions studied will be ~H(~(17)F, p)~(17)F and ~1H(~(17)F, alpah )~(14)O. These experiments will require ~(17)F beams with intensities of 10~4-10~6 ions per second in conjunction with the SIDAR. The ~1H(~(17)F, p)~(17)F reaction will be used to probe resonances in ~(18)Ne which contribute to the ~(17)F(p, gamma )~(18)Ne stellear reaction rate, while ~1H(~(17) alpah )~(14)O will be used to determine the stellar reaction rate of the inverse reaction ~(14)O( alpah , p)~(17)F. In preparation for these experiments, measurements have been mae fo the ~1H(~(17)O, p)~(17)O and ~1H(~(17)O, alpah )~(14)N reaction cross sections. when higher beam currents of ~(17)F become available, a direct measurement of the ~1H(~(17)F,~(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 ~1H(~(12)C,~(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.