IM-179 Miniature Ratemeter

The IM-179/PD was “a miniature gamma ratemeter for placement in aircrew survival kits” that employed a Neher-White pressurized ion chamber filled with argon.. It only used two push button controls: read and test.  The meter and dial are luminescent (Ra-226 radioluminescent paint) . The instructions on the case are self-explanatory.

Range: 0.02 to 200 R/hr on a single non-linear scale

Size: 2.5” x  4.25” x  1.25”

Weight: ca. 9 oz.

Batteries: the commercial version of this instrument uses one 5.2 volt and one 1.34 volt

Manufacturers: Victoreen Instrument Company, Nuclear Corporation of America, Jordan Electronics, Heat Pipe Corporation of America


Jordan (and Victoreen) sold a commercial version of this instrument known as the "Minirad."  One obvious difference was that the Minirad didn't come with a color-coded scale. The Minirad came in three versions: the Model M-50 (0.005-50 R/hr), Model M-100 (0.01-100 R/hr) and the Model -200 (0.02-200 R/hr).


Defense Atomic Support Agency, List of Military and Civil Defense Radiac Devices. DASA 1243 revised, 1966.

Defense Nuclear Agency List of Military and Civil Defense Radiac Devices HQDNA (AR) 3M Revised, August 1987.

Radiac Instruments                   Museum Directory

Last updated: 05/10/11
Copyright 1999, Oak Ridge Associated Universities