γ-rays from the capture in Ta and Au of neutrons from 1 to 4 MeV

Abstract

The γ-ray spectra emitted in the capture of neutrons of energies from 1 to 4 MeV in Ta and Au were measured. In both elements the shape of the spectrum was found to vary only slightly with neutron energy. Using statistical nuclear theory γ-ray spectra were calculated and compared with measurements. Good agreement with experiment was obtained for Au at all neutron energies employing a γ-ray strength function which depends only on the photon energy. In Au the strength function has a peak at 5.5 MeV with a magnitude of about 2% of the integrated γ-ray strength predicted by the E1 sum rule. In Ta the peak in the strength function is much weaker and it was not possible to separate it from the low-energy tail of the giant resonance.