Jordan Model CG 50 Ion Chamber (ca. 1955-1960)
This ion chamber was manufactured by Jordan Electronics (a division of the Victoreen Instrument Company) of Alhambra, California.
It was only capable of responding to gamma rays, hence the G in the model designation. The Model CGB-50, not in the ORAU collection, had a thin window and was capable of detecting betas as well as gammas.
The CG-50 employs a Neher-White design with a floating grid. The resulting output (current) is a logarithmic function of gamma intensity. A nice advantage of this approach is that no guard ring or high meg resister is required! The electrometer tube is hermetically sealed inside the chamber.
Fill gas: Argon (200 psi)
Active volume: ca. 820 cc
Sensitivity: ca. 15 microamps per decade from 0.01 mR/hr to 10,000R/hr
Size: ca. 11" tall and 4" in diameter
Kindly donated by Chuck Abraham.
AEC Radiation Measuring Instruments, RIB-8 (supplement 2) July 1, 1954. Page BIC-19A,B.