Abstract: A mobile or transportable refrigerated container temperature monitoring system which includes digital monitoring and printout devices which provide accuracy and reliability, and means for periodically checking the monitoring means for operability and logging the results. An analog to digital converter is utilzed to convert analog temperature data obtained from thermistor sensors to digital form to provide digital data readout and to drive a digitally responsive printer. Sensing and control devices are provided to prevent printer jamming and compensate for widely varying temperature conditions. Automatically activated testing devices are provided which test and record the functionality of the thermistor temperature sensors by periodically applying a predetermined heat input to the thermistor temperature sensors and recording the responses including responses indicating errors, insuring reliability of the outputted recorded temperature data and pinpointing any improperly functioning sensors.

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.