Capture cross section measurements with a total energy BGO-detector

The total energy BGO-detector was applied to measure capture cross-sections by time of flight method for the neutron energy range 10-200 keV. The properties of the detector (time and energy resolution, sensitivity to the scattered neutrons, efficiency) are discussed. The possibility of the detector was demonstrated with a tantalum cross section measurement. The capture cross section was normalized against the B(n, α₁) reaction. The pulse height spectra of standard gamma-ray sources (energy range 0.1-3 MeV) were applied to calculate the weighting function. It was shown that one may use the spectra of captured γ-rays for isotopes with a well known cross section to determine the weighting function parameters. In addition the new equations for weighting function calculation were suggested.