A random event counter and dead time compensation circuitry for use therein

A random event counter includes circuitry for the compensation of the dead time losses associated with the detector. As the event count rate rises, the transfer function (e.g., the closed loop voltage gain) of an operational amplifier responding to an event count rate signal is modified to compensate for dead time losses experienced at high count rates, so that a meter having a linear scale can be used to display the event count rate. Preferably, an analogue switch controlled by the event count rate signal automatically sets the voltage gain of the operational amplifier at a level corresponding to the desired amount of dead time compensation required to provide an accurate measurement of actual events. The dead time compensation circuitry finds practical application with well-known analogue rate meter circuits of the charge pump type using a Geiger-Mueller tube as the detector. (author)