RCL Slide Rule (1950s)
This slide rule was distributed by Radiation Counter Laboratories, Inc. (RCL) of Chicago, Illinois.
It's had several functions. Given the half life of a nuclide and an elapsed time, it calculates the fraction of the original activity that remains. For a specified count rate and dead time, it determines what fraction the observed count rate is of the actual count rate. For a specified number of counts and count time, it calculates the standard deviation of the count rate. It converts density (e.g., g/cm3) and linear thickness (e.g., cm) to an aerial density (e.g., g/cm2) and vice versa. Finally, it will estimate beta particle energies for a specified range (mg/cm2).
Size: 3.25" x 9.5" (cardboard)
Reference
RCL. Use of the RCL Slide Rule. Instruction Sheet. Copyright date 1949.