Abstract: This invention describes apparatus for and a method of measuring radiation field strength which uses a pulse enabled detector (e.g. G-M tube) and is based on the equation R=K/t, where R is the radiation field strength, t is the time till first strike, and K is a proportionality constant for the given apparatus. The G-M detector is enabled by pulsing the bias voltage across the detector up into its active region and then measuring the elapsed time interval to the incident of first strike. Since the reciprocal of this time is proportional to the radiation field strength, all information necessary to determine the field strength has been obtained. A constant wait time is employed after each strike to assure that the G-M tube full recovery time has expired, and the G-M tube is then enabled and the process repeated. Because of the random nature of radiation phenomena the confidence level that any given measurement is an accurate representation of the true average field strength is low.

Abstract: In a sampled radiation detector including a pulsed Geiger-Mueller detector ube the response to gamma radiation is linearized by providing an additional "reward" pulse after the second of two adjacent pulses of a pulse train generated from Geiger-Mueller pulses outputted from the detector tube during at least two consecutive sampling time periods and wherein the pulse train is thereafter time averaged to provide a measurement signal which is a linear function of the radiation field strength.