GE Radioisotope Decay Calculator (1970s)
The Radioisotope Decay Calculator was marketed by the General Electric Company. More specifically, the calculator identifies GE's Irradiation Processing operation in Pleasanton, California. An ID number, 1M 6/71, would appear to indicate that it was probably produced in the 1970s.
It only has one purpose, to determine the fraction of the source activity that remains after a specified period of time has elapsed. You simply line up the elapsed time with the nuclide half-life and read the result. To make it a little easier, a number of nuclides are indicated on the half-life scale. The back of the calculator converts time units (e.g., hours to days and days to years) and gives the half-lives for a large number of radionuclides.
Size: ca. 3" x 8.5"