The SI-22G is a highly sensitive hard beta and gamma radiation detector tube, made in USSR during the 80’s for the Soviet Military Needs by the Soviet Institute for Scientific Radiation Technology Research.
Notes on sensitivity:
This is a highly sensitive tube, thanks to its cathode material and relatively large size. It is perfect for monitoring equipment and DIY dosimeters, superior to the SBM-20 in this sense. The following chart shows the average of the background readings over a period of 24 hours and each point in the chart was computed using another average of 60 independent, consecutive measurements. The dosimeter used to take the measurements has 1 minute resolution.
Background readings: 70CPM for a background radiation level of 0.12uSv/h
Working Voltage: 360 – 440V
Initial Voltage: 285 – 335V
Recommended Operating Voltage: 400V
Plateau Length: 100V
Plateau Slope: 0.125% / 1V
Inherent counter background (cps): 1.16 Pulses/s
Cobalt-60 Pulse Gamma Sensitivity: 540 pulse/mkR
Inter-electrode (internal) Capacitance: 10pF
Load Resistance: 9 – 13 MOhms
Working Temperature Range: -50 to +70С