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.

IM-9/PD Pocket Dosimeter
IM-9/PD Pocket Dosimeter

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.