RCL Model 10301 GM Tube (1958)

This Radiation Counter Laboratories Model 10301 came with Certificate of Inspection dated 5-6-58. 

Unfortunately, I have no literature regarding this particular tube. However, an RCL catalog states "The RCL Series 103 Detectors are sensitive to beta and low energy gamma radioactivity. Constructed from thin-wall glass or metal tubing, they are suitable for a wide variety of general purpose radioactive detection requirements… Series 103 detectors are virtually insensitive to count rate variation due to temperature change, are non-photosensitive, and exhibit no hysteresis."

Size: 5 3/4" long and 3/4" in diameter

Operating voltage: 950-1100 volts

Cathode: Silver coating on inside of glass wall

Wall thickness: Probably 30 mg/cm²

Donated by the University of Kansas courtesy of Michael Lemon.

Reference

Radiation Counter Laboratories catalog, Radiation Detectors, no date.