Abstract: An alpha particle radiation probe which eliminates the need for any intermediate light coupling devices between the scintillation generating phosphor and scintillation detector while at the same time providing uniform response to alpha particles over a substantially larger area than has heretofore been possible on the order of 100 cm.sup.2 to 150 cm.sup.2. The structure is arranged to quickly replace a light blocking screen that has been damaged in use. Significant reductions in weight and cost are also achieved because of the simpler construction and the elimination of the light coupling devices heretofore used. The apparatus eliminates the need for a second small aperture probe detector for localizing radiation hot spots by providing aperture reducing means quickly attachable to and detachable from the scanning window to reduce its aperture and provide the hot spots detection function simply and inexpensively.

Abstract: The invention substantially eliminates measurement errors in radiation field strength due to circuit propagation time delays and slow drift conditions, Geiger-Mueller tube turn-on time and response curve variations, and the need to manually calibrate the measurement apparatus in high radiation fields to compensate for time errors. The exponential probability function has the property that the expected value for the arithmetic mean of any right hand segment of the curve is always the same provided that the axis is adjusted so that the starting point of the selected segment is zero. The curve is trimmed dynamically each time a new rate is calculated. An individual count of strike events is kept for N separate but consecutive time units, and the counts for the later occurring events are lumped together as the Main Event. After the data collection period ends, a total accumulated time and accumulated count are constructed. This construction begins by examining the Main Event data.

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.