How can I measure radioactivity?
Within my fondness for measuring and controlling everything, I have been thinking for a long time about adding to my list of sensors a Beta and Gamma emission detector (what we usually call a radioactivity meter), a Geiger-Muller counter.
And why do I want a Geiger counter? Well, very simple, because I know that sooner or later an accident will occur or we will suffer an attack and our governments will hide the information from us (look for information about the accident that happened in Madrid, in Moncloa, in the heart of University City, and you will see what I speak to you). And, although they do not hide it from us, I want to be informed first hand and know what is happening in our environment.
Well, the fact is that recently I have encouraged myself with its construction 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 is really very simple, basically it consists of a detection tube, a high voltage source (the tube works at about 450 volts, approximately) and a circuit that is responsible for counting the impulses that are generated in the tube depending on the amount of radioactive particles in the environment.
One possibility was to build a high-voltage generator on one side (fairly easy, a few capacitors and diodes) and a counter (a simple Arduino). The tube, which I will now talk about, and some way of visualizing the results (an LED, LCD or OLED display, a connection to a computer or something similar) would be missing.
Build a Geiger counter kit?
Looking for information about it, I found that it was not worth doing it from scratch. I found a kit on eBay that, for around € 30, provided almost everything (with the tube missing).
I decided to order this kit and in a couple of weeks I already had it at home, from Lithuania.
The Beta and Gamma STS-5 detection tube
The heart of the Geiger counter is the Beta and Gamma STS-5 ionizing radiation detection tube. There are many different tubes with different sensitivities and capable of detecting different types of radiation (alpha, beta, gamma, x-ray, etc.). Although it is highly sensitive laboratory material, contrary to what we might think, its price is not high.
We have at our disposal a large number of surplus tubes, from the former Soviet Union, from the Cold War era, which are easy to find on the internet and whose prices usually range between € 15 and € 30.
In my case I decided on an STS-5 tube, from Ukraine. For € 15, including shipping, in just over two weeks I had my new tube at home.
3D printed box
Finally, and to complete my new Geiger-Muller detector, and give it a good finish, there was a box missing to put it in. Fortunately, I found in Thingiverse a box made to measure for the kit I had ordered, so in a couple of hours my 3D printer had "spat out" one more than apparent box (which I am going to do on my cutting plotter a front vinyl to give it a more professional finish).
Send radioactivity data to the internet
One last detail remains, but the most important: connect it to the network and capture the data it generates, create graphs, launch alarms, etc. The kit and its firmware already include a serial port capable of taking 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 will take care, connected to my Wi-Fi network, to send 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 in this page