Q-Gas Counter (ca. 1949)

Q Gas Counter

The “Q-gas” counter, a windowless gas flow counter that normally operated in the Geiger mode, was manufactured by the Nuclear Instrument and Chemical Corporation of Chicago, Illinois. The original name of the company, Instrument Development Laboratories, was used from 1946 to 1948. From 1948 until 1954, it was known as the Nuclear Instrument and Chemical Corporation. In 1954, the name changed to Nuclear Chicago.

Because it was windowless, the "Q-gas" counter was particularly effective for counting low energy betas, e.g., C-14 and S-35.

“Q-gas,” a mix of 98.7% helium and 1.3% butane, was used if the unit was to be operated in the Geiger mode. If it was necessary to operate it as a proportional counter, methane could be used instead.

Samples were counted in 1.25” planchets. 

Size: 6” x 5” x 10”

Weight: 10 pounds

Operating voltage: ca. 1450 volts

Donated by Ron Kathren.


  • Nucleonics December 1948, p 68.
  • Atomic Energy Commission Radiation Instrument Catalog, page BG-5B1A, date July 1, 1950.