This tube is very hard to find. It’s made from alluminium and glass and is a β-selective Geiger counter. It’s counts only beta’s!

Tech. spec.:

·Radiation determine: (β-) beta soft/hard
·Voltage of start of counting: 750 – 860V ;
·Operating voltage (recommended): 830 – 940V;
·Length of flat part of counting curve (plateau): 80 V
·Slope of the counting curve: < 0.2 %/V;
·Natural background: < 40 counts/min;
·Maximum radiation: 2*10E7 counts/min
·Load resistance: 50-80 MOhm
·Allowable stray input capacitance: < 25 pF
·Working temperature range: -0…+50 C
·Anode material: Platinum (Pt)
·Cathode material: Aluminium (Al)
·Weight: ~20g.
·Dimensions: counter length 128mm, diameter 17mm