test GM trubic СБМ-20 / testing SBM-20 Geiger tubes

Testuji sovětské Geiger-Müllerovy trubice СБМ-20 pomocí korálků z uranového skla a svého detektoru radioaktivity:
danyk.cz/gm_ind...
Testing soviet SBM-20 Geiger tubes using uranium glass beads and my radioactivity detector:
danyk.cz/gm_ind...

[@jeremyp7293]

Hello Danyk, I build a pocket radioactivity detector following the schematic on your website. I have few questions, the one I build draw 35mA at 1,7V and your only 4mA I'm using lithium ion with diodes to lower the voltage but I tried with a regular AA and it still draw a lot more current then the one you build. I was using it like that and then it stop working after like 2-3 hours of use.. I changed all the components even the board and I now I'm sure the tube died. I looked on internet for other schematics but I only decided to change the values on your design like C5 I replaced the 100n by a 4,7n and the anode resistor with a 10M but the current draw did not change. High voltage is there, I can measure 410V between before the anode resistor and B-. I read somewhere that C5 should not be higher than 10n to "avoid burning the quenching gas" After that I don't really want to buy another tube to destroy it like the first one so I added zener diode to get a higher voltage, at around 550V I can see sign of life from the tube but the led is dim and the clics are barely audible, after adding even more zener diodes at around 657V there is no change, the led is still dim when it flash. I can not get higher than 657V with my transformer maybe if I add a stage to the voltage multiplier but will it work ... My tube is a STS-5 and my transformer have no air gap, 2 winding of 15 turns 0.3mm and one winding of about 700 turns 0.1mm. What do you think could have happen ?

[@adamkonrad]

Ta deska je teda známka punku, ale konstrukce pěkná!

[@electronic7979]

Nice

[@nonothebot]

cool !

[@windigo000]

working on EZ under current without supervision i see 😁😎