  A wide variety of detection applications exploit the timing correlations that
result from the slowing and eventual capture of neutrons. These include
capture-gated neutron spectrometry, multiple neutron counting for fissile
material detection and identification, and antineutrino detection. There are
several distinct processes that result in correlated signals in these
applications. Depending on the application, one class of correlated events can
be a background that is difficult to distinguish from the class that is of
interest. Furthermore, the correlation timing distribution depends on the
neutron capture agent and detector geometry. Here, we explain the important
characteristics of the neutron capture timing distribution, making reference to
simulations and data from a number of detectors currently in use or under
development. We point out several features that may assist in background
discrimination, and that must be carefully accounted for if accurate detection
efficiencies are to be quoted.
