Let's Make Robots!

Geiger counter v2

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GM_counter_schematic.JPG211.64 KB

This is my second Geiger counter version. The picture below shows the Geiger counter prototype:

The GM tube and the transformer modem are from Sparkfun. I have slightly modified the original schematic, taking the impulse from the cathode of the tube, not from the anode, and added a Schmitt trigger to get a clear TTL output signal for counting.

The Geiger tube has a mica window for alpha radiation.  I used americium-241 from a dismantled ionization smoke detector to test the Geiger counter. Americium-241 is a so called alpha emitter and has a half-life of 432 years. About one percent of the emitted radioactive energy of 241Am is gamma radiation.

I have attached a video as well to show some testing. I will use the Geiger counter for our weather balloon experiment to measure cosmic radiation.

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fritsl's picture

Amazing!