Russian military NOS Geiger Tube SBM20 for ionizing radiation detection. Can detect beta and gamma radiation. Full analog of STS-5. The tube has good sensitivity for natural background. SBM-20 is one of the best GM tubes you can find in the market today.
Dimension of the tube is 108mm app. x 11mm app.
Typical GM Tube connection example schematic:
- Ionizing Radiation Detection
- Dosimeter / Geiger Counter