A Digital Ratemeter Controlled by the Input Data Rate

Many radiation counter applications require the rapid response speed of a digital ratemeterl & 2, but if large changes in count rate are encountered, a conventional digital ratemeter must be set for a short counting period, producing an excessive number of individual measurements. An instrument is described which avoids this difficulty by automatically adjusting its time base as the count rate changes, the counting period always being such that a preset statistical accuracy is achieved. Further, data readout is inhibited if a measurement does not differ by a statistically significant amount from the last measurement allowed to transfer to the readout line, or if a sudden increase in rate occurs while a measurement is being taken. For applications in which a single digital ratemeter scans the output lines of a number of detectors, a preset time base limit is provided to prevent time being lost in making measurements of very low count rates or where a counter has failed. Among the display modes is a prediction mode which indicates the rate with increasing accuracy as the count is accumulated. The display utilizes scientific notation, which is very economical of display components and output lines, resulting in an instrument which has fewer parts than a scaler-timer of conventional design.