DIY Geiger Counter

Ever since I was a child I’ve wanted a Geiger counter. Recently the perfect opportunity arose that I sought to take advantage of. There is a required creative project in my particle & nuclear physics course. In addition, I realized that I could give a presentation on radiation detection and building a Geiger counter in my physics communication course. What’s that old saying, “Kill two birds with one stone” (well technically three, but whatever). So after some thinking and planning I finally decided to build a Geiger counter.

Now I had some choices to make: to go the hardcore DIY route (building the circuit myself), or obtain a pre-fabricated Geiger counter circuit board. The idea of creating one from scratch and acquiring all of the parts from a local electronics store is enticing, however it would probably end up a functioning, big, ugly mess with wires and parts all over the place. So, I decided to take the path of least resistance that would result in a device that is much more portable and functional. I bought a kit that includes everything you need (besides the tools, Geiger-Müller tube, batteries, wires, and switches) from diygeigercounter. I ordered mostly everything else I needed, and then waited for the packages to arrive like it was Christmas eve.

Upon beginning the journey I realized that the soldering was going to be a serious undertaking for someone who hasn’t soldered more than two wires together before. The solder I had originally ordered was way too large to use. Once I obtained the correct size solder I was on my way. The soldering at first was all about getting used to it. After a dozen or so resistors I was starting to get the hang of it. A helping hands device was really convenient to have and a smart purchase. After a few rookie mistakes and more time than I’d like to mention, I finally completed what I consider to be a good first soldering job.

After popping on the LCD (sold separately from the kit), connecting the tube, and 9V battery, I started to hear clicks! I thought to myself, “Thank God”. I would’ve been pretty mad if I had just spent all that time and ended up with a complete dud. I then tested the Geiger counter with a thorium lantern mantle (obtained via Ebay) and got counts fluctuating around 1308 counts per min. “It’s working!”

Now all that was left was to find/make/buy a housing for it, and install a power switch. I ended up going with a Pelican micro case I found at Best Buy. It was fairly inexpensive and has the added benefits of being water-proof and crush-proof. I obtained a switch from Radioshack and connected it to the battery and the board. I’ll probably also eventually add switches for display on/off and click/off/tone mode. One thing I have noticed is that the case blocks most beta particles. This is due to it being the thick crush-proof plastic. There are three options: open the case when using, drill holes near the tube, drill a hole in the side for an external tube to be used in a wand-like apparatus. The latter is the most appealing to me as the case can still be waterproofed that way. After all was said and done, I was pretty happy with the outcome.

The tools used.

The tools used.

Electrical components minus the resistors I had already soldered.

Electrical components minus the resistors I had already soldered.

Double checking resistances.

Double checking resistances.

Soldering

Soldering

Finished soldering the resistors.

Finished soldering the resistors.

More soldering

More soldering

The finished circuit board.

The finished circuit board.

Testing with thorium lantern mantle.

Testing with thorium lantern mantle.

Inside the case before the switch was installed.

Inside the case before the switch was installed.

The final product.

The final product.

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