Microscopic nuclear models and light element standard cross-sections

For the 4He compound system we used the Argonne V18 NN and the Urbana IX NNN potentials and allowed for the physical 3H + p, 3He + n and 2H + d channels, together with a very large number of distortion channels, which have no asymptotic part but which are necessary to give the RRGM scattering wave function enough freedom in the interaction region. The 7Li compound system has already been studied using an effective NN force that is tailored to bind deuteron, triton and the alpha particle with pure S waves. This potential allowed the reproduction of the 6Li + n threshold relative to that of the α + triton, but not the higher ones. Only 4He-3H and 6Li-n channels yielded low lying poles in good agreement with known results. Adding more channels in order to come close to the calculations resulted in R matrix poles accumulating just above all thresholds. The same behaviour occurred for the 11B compound system. When the cross-section for the 6Li(n,t)4He reaction became available from the R matrix analysis as individual partial waves, we carried out calculations for various effective NN potentials. These calculations showed qualitative agreement for the 7Li system and explained interference patterns found in an R matrix analysis. New structures were proposed for the 11B system at energies above the standards region