The use of C 6D 6 detectors for neutron induced capture cross-section measurements in the resonance region

Abstract

Hydrogen-free deuterated benzene C 6D 6 liquid scintillators are widely used for high resolution neutron capture cross-section measurements at time-of-flight facilities, using the total energy detection principle in combination with the Pulse Height Weighting Technique (PHWT). The quality of the data deduced from such measurements depends on the accuracy of the detector response that is used in the calculation of the weighting function and on the normalization procedure. In addition, for nuclei with small capture to scattering ratios, i.e. light and near neutron magic nuclei, a correction for the sensitivity of the capture detector to the scattered neutrons is required. The MCNP code was used to simulate both the γ-ray and neutron transport in a C 6D 6 detection system including its surroundings. The weighting functions and neutron sensitivity were then deduced from the simulations and validated by experiments. The simulations have also been used to identify the sources of uncertainties in performing capture cross-section measurements with C 6D 6 detectors.