Yrast decays in K43

High-spin states in K43 were studied using the Be9(36S,pn)43K reaction. Threefold (p12) coincidence data and -ray intensity ratios were used to establish a decay scheme and identify negative- and positive-parity yrast decay chains. The 15/2- yrast state is relatively poorly aligned prior to decay. Energies of positive-parity levels predicted by Johnstone are in good agreement with experiment

Astrophysically important 19Ne states studied with the 2H(18F, α+15 O)n reaction

The nuclear structure of 19Ne near the proton threshold is of interest for understanding the rates of proton-induced reactions on 18F in novae. Analogues for several states in the mirror nucleus 19F have not yet been identified in 19Ne indicating the level structure of 19Ne in this region is incomplete. The 18F(d,n)19Ne and 18F(d, p)19F reactions have been measured simultaneously at Ec.m. = 14.9 MeV. The experiments were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL) by bombarding a 720-μg/cm2 CD2 target with a radioactive 18F beam. The 19Ne states of interest near the proton threshold decay by breakup into a and 15O particles. These decay products were detected in coincidence with position-sensitive E-ΔE silicon telescopes. The α and 15N particles from the break up of the mirror nucleus 19F were also measured with these detectors. Particle identification, coincidence, and Q-value requirements enable us to distinguish the reaction of interest from other reactions. The reconstruction of relative energy of the detected particles reveals the excited states of 19Ne and 19F which are populated. The neutron (proton) angular distributions for states in 19Ne (19F) were extracted using momentum conservation. The observed states in 19Ne and 19F will be presented

S-wave scattering lengths for the Be 7 +p system from an R-matrix analysis

The astrophysical S factor for the radiative proton capture reaction on Be7 (S17) at low energies is affected by the s-wave scattering lengths. We report the measurement of elastic and inelastic scattering cross sections for the Be7+p system in the center-of-mass energy range 0.474-2.740 MeV and center-of-mass angular range 70-150. A radioactive Be7 beam produced at Oak Ridge National Laboratory's (ORNL) Holifield Radioactive Ion Beam Facility was accelerated and bombarded a thin polypropylene (CH2)n target. Scattered ions were detected in the segmented Silicon Detector Array. Using an R-matrix analysis of ORNL and Louvain-la-Neuve cross-section data, the s-wave scattering lengths for channel spins 1 and 2 were determined to be 17.34-1.33+1.11 and -3.18-0.50+0.55 fm, respectively. The uncertainty in the s-wave scattering lengths reported in this work is smaller by a factor of 5-8 compared to the previous measurement, which may reduce the overall uncertainty in S17 at zero energy. The level structure of B8 is discussed based upon the results from this work. Evidence for the existence of 0+ and 2+ levels in B8 at 1.9 and 2.21 MeV, respectively, is observed