IM-9/PD Pocket Dosimeter

The IM-9/PD is a military direct reading pocket dosimeter that measures gamma ray exposures in the 0 – 200 mR range.   For some reason, there were more versions produced of the IM-9 than of any other military dosimeter. The following photograph shows some of these: from the top down, the models IM-9, IM-9A, IM-9B, IM-9C, IM-9D, IM-9E, and the IM-9F.  As can be seen, there were minor variations in size  -  which chargers can be used with a dosimeter can depend on the diameter of the dosimeter barrel.

The model IM-9 used a removable dust cap to cover the charging contact at the opposite end of the dosimeter from the eyepiece.  The other models didn't need the dust cap because they used a hermetically sealed diaphragm. Despite this, the only model with a dust cap in the photograph is the IM-9E.

Standard Models:  1957    IM-9, 9A, 9B, 9C and 9D.

                                1966        IM-9C, 9E, 9F and 9G

                                1975    IM-9E, 9F, 9G, and 9H

                                1987    IM-9E, 9F, 9G, and 9H  

Size: 3 5/8” long and  7/16” diameter (IM-9) or 3.5” long and 0.5” diameter (other models)

Weight: 2 oz. (IM-9) or 0.5 oz. (other models)

Ionization Chamber Volume:  ca. 3 cc

Manufacturers: 

Landsverk (IM-9 contract date 1947; IM-9F contract date ca. 1959-61)

Kelly-Koett (IM-9 and 9A contract dates 1948, IM-l 9B contract date 1950) 

Victoreen (IM-9C contract date 1951; IM-9E contract date 1957)

Arnold O. Beckman (IM-9D contract date 1951/53).

Bendix

References

Directory of Radiac Equipment NAVSHIPS 94200.5, no date, ca. 1961-62.

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

Naval Electronic Systems Command, List of Radiacs in the Navy Program P-9670-1, February 1975.

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

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