Скачать или смотреть Geiger Counter with AVR and SI-8B Pancake Probe

I used a Russian-built SI-8B (aka СИ8Б) pancake tube and built a geiger counter with it using a switched inductor buck-boost converter. The probe itself is amazing, although not cheap (around $100 on Ebay) -- but definitely worth the price in my opinion. In the video I show the main parts, the schematic and compare it to the Gamma Scout in terms of sensitivity. The schematic in the video is wrong (the HV part is connected to the drain of the N-FET, not to the 12V -- thanks to fatalerror8000 for pointing this out). Also, the part names in the schematic are messed up. Both mistakes are corrected in the PDF schematic at http://johannes-bauer.com/electronics...

UPDATE: As StrixNoctis noted the datasheet of the SI-8B indicates a maximum working current of 18.2µA. So the resistor that is in series with the tube should be increased from 10 MOhm to 30 MOhm to be in the safe working area of the tube.

Note that instead of the 2SK2480 you can use pretty much any fast N-MOSFET (as can be found abundantly when scavenging parts off a SMPS or TV) and instead of the BY299 you can use any fast recovery time schottky diode that withstands more than 500V. The BC548 and BC558 can be replaced by any general purpose NPN/PNP transistor.

Music by www.LukHash.com
Video License: CC BY-SA 3.0