Geiger Counter (Radioactivity Meter)

How can I measure radioactivity?

Within my penchant for measuring and controlling everythingI've been thinking for some time about adding to my list of sensors a Beta and Gamma emissions (what we usually refer to as a radiation meter), a Geiger-Muller counter or Geiger meter.

When the Chernobyl incident occurred in the Soviet Union (specifically, in what is now Ukraine), I was 20 years old and was already part of what we could then call the "maker community". I was a radio amateur, an electronics and computer enthusiast, and the truth is that I was very impressed by the incident, especially because made me realise that we didn't know anything about what was really going on..

Why do I want a Geiger counter? Quite simply, because I know that sooner or later an accident will happen or we will suffer an attack and our governments will hide the information from us (look for information on the accident that occurred in Madrid, in Moncloa, in the middle of the University City, and you will see what I am talking about). And, even if they do not hide it from us, I want to be informed first hand and know what is going on around us.

Also, on occasion when there have been references to radiation in the news, it has been good for me to have my own Geiger counter and to be able to measure radiation, when it has been convenient for me.

For example, when they said that the fish we were eating was contaminatedThe report said that he was affected by the Fukushima radiationThe fish we brought home can be analysed, which gave us extra peace of mind (and I know that there are people who analyse fish daily with meters similar to this one).

Well, the fact is that I have recently decided to build it and it is already working.

Make a Geiger counter from scratch?

I spent a long time thinking about how to do it. A Geiger counter really is very simplebasically consists of a detection tubea high voltage source (the tube operates at about 450 volts, approximately) and a circuit impulse counter generated in the tube depending on the amount of radioactive particles in the environment.

One possibility was to build a high voltage generator on the one hand (easy enough, a few capacitors and diodes) and a counter (a simple Arduino). It would lack the tubeI will now talk about, and some way of visualising the results (an LED, LCD or OLED display, a computer connection or something similar).

Building a Geiger counter kit?

Looking for information about it, I found that it was not worth designing it and doing it from scratch. I found a kit on eBay that, for about €30The new system provided virtually everything (apart from the tube).

I decided to order this kit and in a couple of weeks I had it at home, coming from Lithuania.

I could save myself the trouble of designing it and spend that time on improving the meter, by equipping it with Wifi and connecting it to the internet.for example.

Geiger counter assembly

The assembly of the kit was quite simply The 50 or so SMD components are already soldered to the board and only a few normal components need to be soldered on. Even a beginner could do it without any problems, with a little bit of care.

The STS-5 Beta and Gamma Radiation Detection Tube

The heart of the Geiger counter is the ionising radiation detection tube Beta and Gamma STS-5.

There are many different tubes with different sensitivities and able to detect different types of radiation (alpha, beta, gamma, x-rays, etc.).

Although it is highly sensitive laboratory equipmentcontrary to what we might think, its price is not high.

We have at our disposal a large number of surplus pipes, from the former Soviet Unionfrom the Cold War era, which are easy to find on the internet and whose prices generally range from 15€ y 30€.

In my case I went for one STS-5 tube, from Ukraine. For 15€.I had my new tube at home in just over two weeks, including shipping.

3D printed box

Finally, to complete my new Geiger-Muller detector, and to give it a nice finish, I needed to a box to put it in.

Fortunately, I found in Thingiverse a custom box for the kit I had ordered, so that in a couple of hours my 3D printer had "spat out" a more-than-apparent box (to which I made a yellow vinyl front with my cutting plotter to give it a more professional finish).

Send radioactivity data to the internet

One last detail remained, but, for me, the most important: connecting the Geiger counter to the internet and capture the data it generates, create graphs, alarms, etc..

The kit and its firmware already include a serial port able to extract this data, so the next step will be to complete the detector with an ESP8266 (which I want to put inside the same box) and which, connected to my wifi network, will be responsible for sending the data to the rest of the systems in my house. But this will be the subject of a new blog post...

Edit: You can find this new article on how to send radioactivity data to the internet in real time on this page