A MEASUREMENT OF THE C-14(N, GAMMA)C-15 CROSS-SECTION AT A STELLAR TEMPERATURE OF KT = 23.3 KEV

The capture cross section of C-14 has been determined by a fast cyclic activation technique. The measurements were carried out at the Karlsruhe 3.75 MV pulsed Van de Graaff accelerator using the Li-7(p, n) reaction close to the reaction threshold to generate neutrons with a distribution resembling a Maxwell spectrum of kT = 25 keV. The activation sample consisted of 605 +/- 15 mg carbon powder enriched in C-14 by 89%. The C-14 capture cross section was measured relative to the Au-197 standard cross section. The activity produced by neutron captures in the C-14 sample was counted with a high-resolution HPGe detector via the characteristic 5297.79 keV C-15 gamma-ray line. The C-14 capture cross section at kT = 23.3 keV was found to be (1.72 +/- 0.43) mu-barn.