Before dosimeters can be used to measure gamma radiation, the self-contained fiber voltmeter and ion chamber (electrometer) must be charged to approximately 165 volts D.C. with the central charging pin being positive in respect to the barrel.

Most all available dosimeter charging units may be used to charge dosimeters. These chargers can use a variety of input power, such as batteries, A.C. line voltage, piezoelectric crystal voltage generators, friction voltage generators, etc. Charger electronic circuitry provides the proper adjustable output voltage and polarity required. It is only necessary to place the dosimeter's charging end upon the charger's charging pedestal with sufficient force to actuate the internal dosimeter switch and the charger switches. Manipulate the charger voltage controls while viewing the dosimeter's graduated scale (reticule) through the eyepiece end of the dosimeter and adjust the hairline fiber image to zero. Remove the dosimeter from the charger. More instructions on use of charger

The charged dosimeter is now ready, whether to be worn on the person, or placed in an area to be monitored for radiation exposure

At any time during or after radiation exposure, the dosimeter may be read to determine the total quantity of radiation to which it has been exposed since charging to zero

To take a reading on the dosimeter, it is merely necessary to look at an illuminated light colored surface, or a source of light through the eyepiece end of the instrument.

Because the dosimeter scale is linear, it is possible to determine the total amount of radiation exposure for any selected period of time by merely subtracting the reading taken at the start from that taken at the end of the selected period. Accordingly, it is not necessary to recharge the dosimeter after each reading, unless the instrument reads close to full scale.