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I want to make a Geiger counter for urban exploring


Active Member
As the title says, I would like to build a Geiger counter for a place in in Georgia that I would like to explore.
Although people say there was a no longer a trace of radiation I would still like to see for myself.
Does anyone know of a good schematic I can use? My main objective is for the clicks to be audible, and if I wanted, to change from speaker to just an led as an indicator. I would like to run it off either 4 AA batteries or a 3.7 volt lithium. And if possible to adjust sensitivity, but if that’s too hard I can do without it.
I was thinking of using a 555 as the square wave generator for the tube let me know if that would be a good idea.
Thank you,


Active Member
And if you don't already have a Geiger tube, the price of those is going to curl your toes - not cheap.

There used to be a few cheapish ones out of Russia, but I think they may have dried up now.

Google 'Geiger Counter kit' to see what is out there.


Well-Known Member
Most Helpful Member
Tubes are available on ebay - eg.

Some types with quartz windows will detect alpha as well. That's difficult as alpha is blocked by almost any material.
One here:

An old unit you can repair of modify may be a good option, they have more facilities than simple kts and some level of calibration. Something like this?

Ignore all the small plastic "radiation detectors" being sold new, they are generally scams that pick up RF etc., not ionising radiation.

There are no places with "zero radiation" outside of specially screened facilities! The Earth itself is radioactive, some types of rock more than others.

This is my Geiger counter, I've had it near 50 years - it came out of one of the UK nuclear sites, sold off because the battery failed.



Well-Known Member
Most Helpful Member
you can make an ionization chamber with simple materials. they aren't as sensitive as G-M tubes, but they don't require argon or helium at partial pressure, and if made right an ionization chamber CAN detect alpha, beta, and gamma radiation by using metal screen at one end instead of sheet metal (closing off the end with sheet metal blocks beta and alpha particles). just google "ionization chamber diy" and you will see some very simple devices that work.

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