A 50 cm diameter, 1.7 cm thick disc of NaI(Tl)
scintillator has been mounted to permit edge
viewing by four photomultipliers. Energetic
heavy ions passing through the scintillator at
different positions cause a variation in the
division of light among the photomultipliers.
We have achieved a performance close to the
expected limit for 670 MeV/n路 路neon. Calculations
of expected response using an optical
model agree well with the measurements
