SBM20 Tube Hard Beta and Gamma Radiation GM Detector

Military  SBM-20  ( СТС-5 ;STS-5) Hard Beta and Gamma GM Detector (TESTED)
Made in USSR 
Lot of  1  piece.

SPECIFICATIONS:
Working Voltage                                    360 - 440V
Initial Voltage                                        280 - 330V
Plateau Length                                      80V
Plateau  Slope                                        0.125% / 1V
Inherent counter background (cps)       0.45 Pulses/s
Pulse Sensitivity                                     24 Pulses/s
Interelectrode Capacitance                    7pF
Load Resistance                                     5 - 10 MOhms
Working Temperature Range                 -40   +50 С
Length                                                    110mm
Diameter                                                 9mm