An independent measurement of the C(, )O cross section with the Karlsruhe 4 BaF detector

An independent approach for the measurement of the C-12(alpha, gamma)O-16 cross section at low energies has been performed at Forschungszentrum Karlsruhe using the 4 pi BaF2 detector and the pulsed 3.7 MV Van de Graaff accelerator. Covering the full solid angle, the Karlsruhe 4 pi BaF2 detector combines high gamma-ray efficiency with a 42-fold segmentation. This allows one to measure the total C-12(alpha,gamma)O-16 cross section and the angular distribution simultaneously. The Van de Graaff accelerator was operated in pulsed mode in order to discriminate neutron background from the C-13(alpha,n)O-16 reaction. With a pulse width below 2 ns and beam currents of up to 6 mu A, the cross section could be measured at center of mass energies between 1.0 and 1.51 MeV yielding angular distributions with up to 12 angles.