Tracerlab TGC-3A End Window GM Tube

Tracer TGC 3A GM Tube

Tracerlab's model TGC-3, like the TGC-1 and TGC-2, was a glass-walled end window GM tube designed for beta counting. The earliest reference I have found for it is 1950. The TGC-3 and TGC-3A tubes were exactly the same. The difference was that the TGC-3 came with a set of beryllium and copper absorbers (disks).

Size: 3.85” long and 1.5” inner diameter

Window thickness: 1.9 mg/cm² mica

Wall: Glass, > 300 mg/cm², stainless steel on inside

Anode: Tungsten central wire.

Operating voltage: 1100-1400 V

Plateau length: 300 volts

Fill gas: Argon

Fill gas pressure: 720 mm Hg

Dead time: ca. 200 us

Base: Four prong ceramic base

Kindly donated by Randy Liebermann.


  • Advertisement, Nucleonics July 1949, Inside front cover.
  • AEC Radiation Instrument Catalog, page date May 1, 1950.
  • Tracerlog No. 30 price list, November 1950.
  • Tracerlab Inc, Catalog E, March 1958.
  • Tracerlog No. 30 price list, November 1950.