It is the first test to which
all delivered modules are subjected. The bare module is air gap coupled to
a PMT---EMI 9822QB. The cosmic
rays traversing the crystal produce signals whose charges are integrated
during the fast gate (100 ns) and the long (total) gate: 1000 ns. The ratio of
the charge collected during the fast gate to that measured in the long gate
gives the F/T of that particular crystal. The F/T is an important measurement
of the quality of the CsI ingot from which the module was cut. The length of
the fast gate is also the nominal length of the delayed pion gate (DPG)
during which pion beta and 
events are registered.
For good energy resolution in the calorimeter, the F/T for each module must be
or better.