21 LOW NOISE PREAMPLIFIERS, LINEAR AMPLIFIERS, DISCRIMINATORS, GATE GENERATORS, TIMERS, LINEAR GATES, POWER SUPPLIES,BIASED AMPLIFIERS, PULSE STRETCHERS, BASE LINE RESTORERS, CROSS OVER PICK-OFFS, PULSE STRETCHER MULTIPLEORS, SCINTILLATION DETECTOR PREAMPLIFIERS, DUAL SUMMER AND INVERTORS, AND COINCIDENCE INSTRUMENTS