  Coincidence and time-of-flight measurement techniques are employed to tag
fission neutrons emitted from a 252Cf source sealed on one side with a very
thin layer of Au. The source is positioned within a gaseous 4He scintillator
detector. Together with alpha particles, both light and heavy fission fragments
pass through the thin layer of Au and are detected. The fragments enable the
corresponding fission neutrons, which are detected in a NE-213
liquid-scintillator detector, to be tagged. The resulting continuous
polychromatic beam of tagged neutrons has an energy dependence that agrees
qualitatively with expectations. We anticipate that this technique will provide
a cost-effective means for the characterization of neutron-detector efficiency
in the energy range 1 - 6 MeV.
