Isotope Handling Calculator Mk. III (ca. 1960s, 1970s)

The Isotope Handling Calculator Mk. III, was distributed by Amersham. It is an updated version of the Isotope Handling Calculator developed by the Isotope Division AERE Harwell England. Like the first version (No. 1) of the calculator, which was described in the August 1953 issue of Nucleonics, the Mk. III is made of 1/8" plastic. 

Isotope Handling Calculator Mk. III (ca. 1960s, 1970s)

Its purpose was to facilitate certain calculations involving the following radionuclides: Na-24, Co-60, Ra-226, Cs-137, Ir-192, I-131 and Au-198. The original version of the calculator dealt with Ta-182, but not Cs-137. The calculator relates the radionuclide source activity (uCi, mCi, or Ci) to the gamma exposure rate (R/hr) at a specified distance. It also indicates the safe handling time per day (based on 100 mR/day), and the reduction in the exposure rate due to a specified thickness (cm or inches) of lead shielding. The instructions are indicated on the back side of the calculator (not shown). 

Size: 8.5" diameter


  • R. West. Isotope Handling Calculator. Nucleonics August 1953, page 50-40.
  • U.K.A.E.A. An Isotope Handling Calculator (MK III) For gamma-ray sources with lead shielding. Report RCC-R165 (kindly provided by Ron A Knapp).