The "Ionometer" (ca. 1950s)

The Ionometer is an electroscope that indicates the cumulative exposure via a dial on the top of the unit. The bottom of the device is a rotating knob with two positions: "charge" and "measure." For what it’s worth, one definition of an ionometer is that it is a device used for measuring the intensity of ionizing radiation.

It is very similar in its function to a direct reading pocket dosimeter—in fact, it could easily have been included in the Dosimeter section of the collection. The major difference is that the Ionometer is more easily read. The scale is 0-0.2R (0 to 200 milliroentgen), the range typical of most pocket dosimeters.

It was produced by the Nassau Distributing Company of New York. The only information I have about this company is that it was involved in a lawsuit in 1952.

As can be seen in the accompanying photo, all the lettering has been done freehand, something that suggests that it was a prototype. This makes sense because it was sent to the Office of Civil Defense when the latter was looking for inexpensive radiation detectors/dosimeters for the public.

Size: ca. 4 1/2" long and x 1" in diameter

Donated by Jack Greene.