A Fast Single Channel Pulse Height Analyzer for Precision Timing with Scintillation Counters

For fast precision time measurements with scintillation detectors zero, crossing synchronisation and fast energy selection on the current pulses from the detector seem in many cases to be the best choice. A fast S.C.A. has been developed giving both a zero crossing and a leading edge output for timing purposes. Input pulses are analyzed from 4 to 400 mA. The total time slewing of the zero crossing output is about 150 ps over the whole range of input amplitudes. Particular care has been devoted to the logic of the instrument, assuming always correct time information being carried by the output pulses. Measurements, performed with scintillation detectors, gave a best resolution of 190 ps using on both channels the zero crossing output and narrow energy selection. Good results have been obtained also with very wide energy selection.