M-2 Radiation Calculator (1960s)
The M-2 Radiation Calculator (copyright date 1962) was developed for the Radiological and Chemical Defense Service of the New York State Civil Defense Commission and manufactured by Wade Products Inc. of NYC. If the exposure rate (rads/hr) is known at a given time after a nuclear explosion, the calculator predicts the exposure rate at any other time. It also estimates the dose to personnel who are in the area at specified periods of time after the explosion. The back of the slide rule has the instructions (bottom photo). It is another variation of the slide rule developed a decade earlier by William Orr for the Connecticut State Office of Civil Defense.
Size: 5" diameter