  In the evaluation of novel scintillators, it is important to ensure that the
spectrum of the light emitted by the scintillator is well matched to the
response of the photomultiplier. In attempting to measure this spectrum using
radioactive sources, it is found that so few photons are emitted per
scintillation event that conventional spectroscopic techniques cannot easily be
used. A simple photon counting technique is presented, using two
photomultipliers operated in coincidence, the one viewing the scintillator
directly, while the other views it through a monochromator. This system allows
the spectrum to be measured without using specially cooled photomultipliers,
intense radioactive sources or particle beams.
