
Detectors
126
method exists for experimentally determining the detector threshold and mea-
suring the detector eciency as a function of neutron energy. It consists of
using a gamma-ray source to establish reproducibly the discriminator setting
on the detector, n–p elastic scattering to measure the relative neutron detec-
tion eciencies over the complete range of interest, and the
2
H(d,
3
He)n reaction
to obtain several absolute neutron detection eciencies with which to normal-
ize the relative values. e results of the relative eciency measurements are
shown in Figures 4.9 and 4.10. Shown in Figure 4.10 are the theoretically calcu-
lated eciency ...