BRL RADIAC Calculator No. 2 (late 1950s, 1960s)
The RADIAC Calculator No. 2 was produced by Blundell Rules Limited of Weymouth England. Since the company moved to Weymouth in 1956, and changed their name in 1964, it probably dates from 1960 plus or minus a few years. It works as follows: if the exposure rate (roentgens/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 design is based on the Radiation Dosage Calculator developed by William Orr at the University of Connecticut for the Connecticut State Office of Civil Defense. The U.S. Army employs a military version of this calculator: the ABC-M1A1.
Size: 5" diameter