CD V-750 Model 6 Dosimeter Charger R&D Prototype
The primary purpose of the Model CD V-750 was to charge civil defense dosimeters (CD V-138, 730, 740, and 742). By charge, we mean adjust the dosimeter so that the quartz fiber, visible through the eyepiece as a fine line running vertically across the scale, is set at zero. What most people think of when they think of a dosimeter charger (which is not that often), is a 4" x 4" x 2" box with a knob and charging contact on the top and a flashlight battery inside (e.g., Models 1-5 of the CD V-750). There are other types however.
Several civil defense instruments were identified in Radiological Instruments: An Essential Resource for National Preparedness (September 1986) as being under development during the 1980s. One of these was “a piezoelectric charger for dosimeters developed at Oak Ridge National Laboratory (ORNL).” Later, this device became the CD V-750 Model 6.
The charger shown here is an R & D prototype of the Model 6 that was produced in the 1970s. Details of its construction can be found in US Patent Number 4,494,002 Pistol-Shaped Dosimeter Charger.
By squeezing the trigger, a stress is created on a piezoelectric crystal. This stress produces the potential that is used to charge the dosimeter. The beauty of it is that it requires no batteries!
Donated by one of its developers, Frank Manning.