  This paper reports a series of measurements that characterize the directional
dependence of the scintillation response of crystalline melt-grown and
solution-grown stilbene to incident DT and DD neutrons. These measurements give
the amplitude and pulse shape dependence on the proton recoil direction over
one hemisphere of the crystal, confirming and extending previous results in the
literature for melt-grown stilbene and providing the first measurements for
solution-grown stilbene. In similar measurements of liquid and plastic
detectors, no directional dependence was observed, confirming the hypothesis
that the anisotropy in stilbene and other organic crystal scintillators is a
result of internal effects due to the molecular or crystal structure and not an
external effect on the measurement system.
