Radiac Computer- Indicator CP-95A/PD

This is quote from the manaul:
Radiac Computer-Indicator CP-95A/PD is designed as a portable radiac computer-indicator, for computing & indicating the total amount of X and gamma radiation to which Radiac Detector DT-60()/PD has been exposed (and thus revealing the X and gamma radiation to which the wearer of the DT-60()/PD had been exposed). The CP-95A/PD operates in conjunction with Radiac Detector DT-60()/PD (not supplied) which contains a specially compounded silver-actuated phosphor glass. When the total radiation dosage of a DT-60()/PD is to be measured, the DT-60()/D is placed in Radiac Computer-Indicator C-95A/PD and exposed to a source of ultraviolet light. The ultraviolet light causes the silver-activated glass to emit an orange luminescence, the intensity of which is proportional to the total amount of radiation the glass has received. The intensity of the orange luminescence is measured by a photomultiplier tube which is fitted with a filter to prohibit the passage of blue and green light. The photomultiplier tube employs the principle of secondary emission to amplify the initial electron emission caused by the filtered orange illumination of the light-sensitive cathode. The output of the photomultiplier tube is applied to an indicating circuit to indicate the total amount of radiation to which the wearer of the DT60()/PD has been exposed.