Coincidence Circuit of Medium Resolution

A reliable coincidence circuit of medium resolution with resolving time adjustable between 0.4 and 0.01 microsecond is described. The circuit uses a biased-diode pulse level selector in either channel, followed by a triggered blocking oscillator. Narrow and constant shape pulses so produced in the channels actuate a coincidence tube, output from which keys a rectangular pulse generator for turning on a power tube connected to a mechanical impulse recorder. Preliminary applications to the study of time fluctuations and delays in proportional counters and to proton time of flight measurements are described.