Portable Integrating Radiation Monitor (ca. 1960s)

Portable Integrating Radiation Monitor (ca. 1960s)

This is a portable integrating ionization chamber designed to measure the dose equivalent rates in the pulsed fields around accelerators. It was developed at Brookhaven National Laboratory, probably in the 1960s, and was retired from service during the early 1980s. For obvious reasons it was known as the "jug" but the official designation was the IH-35.

The chamber wall is made of polyethylene and more or less tissue equivalent. Since it also operated in the integrating mode, it could be calibrated in terms of a dose equivalent rate (a quality factor of ten was assumed). The "jug" was an ideal and reliable instrument for use in the complex radiation fields at Brookhaven's AGS and Cosmotron facilities—these fields primarily consisted of neutrons, muons, gamma rays coming out perpendicular to the accelerator's target.

Ranges: 0-50, 0-500, 0-5,000 mrem/hr

Size: 12" high and 7" in diameter

The instructions, taped on the chamber wall, describe a somewhat involved process of zeroing and cycling the meter. After this had been accomplished, the reading could be obtained by pushing and releasing the small button on the handle.

Portable Integrating Radiation Monitor (ca. 1960s)

Donated by Brookhaven National Laboratory courtesy of Steve Musolino.


  • Steve Musolino, personal communication
  • Carl Distenfeld, personal communication