An accurate logarithmic counting-rate meter covering a wide range

The paper describes an instrument whose output voltage is proportional to the logarithm of the rate at which the input pulses are received. This relationship can be made to hold, to a good approximation, over a range of pulse rates of from 1 to 105 pulses per second without range switching. The causes of inaccuracy and instability are examined, and it is shown that errors may be expected to be less than 10% of the pulse rate throughout the range of a five-decade instrument; the errors are correspondingly smaller in an instrument covering a smaller range. The paper shows how the instrument may be used in the investigation of some problems in nuclear physics.