Neutron capture of Si-30

At the Karlsruhe and Tubingen 3.75 MV Van de Graaff accelerators the cross section of the reaction Si-30(n,gamma)Si-31(2.62h) was measured by the activation technique via the beta spectrum of the Si-31-decay. Natural silicon samples of 50 to 90 mum thickness were irradiated back to back with gold foils which served as capture standard. Neutrons were generated using the Li-7(p,n) and T(p, n) reactions. The capture cross section was measured at the neutron energies 25, 30, 52, 104, 149, 180, and 215 keV, respectively. The data have been interpreted with the help of DWBA calculations. We find that the measured cross sections are strongly determined by direct capture and that resonant contributions have been overestimated previously. (C) 2002 Elsevier Science B.V. All rights reserved.