GM from Harvard University (late 1940s)

This "home-built" GM detector was constructed at Harvard University, possibly in the late 1940s.

When used, it was located at a station just inside the door to the cyclotron building where the cyclotron's designer, Robert R. Wilson, conducted his pioneering work in the field of proton therapy.

The GM has an "OUT" jack in the lower left corner for an audio output, but it seems to have been used rarely, if ever.

In the upper right-hand corner is a neon lamp (broken) that would flash and provide a visual indication of the count rate

Detector: Side wall GM in external probe. There is only a tiny fragment of a blue label on the tube (which appears to be the Amperex Model 90NB).

Ranges: 0-0.2 mR/hr 0-2 mR/hr 0-20 mR/hr

Size: 6” x 9” x 5”

Donated by Harvard University courtesy of Dr. Joseph Ring.

Reference

Joeseph Ring. Personal communication.