Surely you have seen many times, especially in movies, series or documentaries, the famous Giger counter, for measuring ionizing radiationWell, you should know that you can create one yourself using Arduino. A very interesting science project with which you will learn about these devices and you will also be able to make measurements in your area.
So, here we go…
What is a Geiger counter?
For those who don't know yet, a Geiger counter, also known as Geiger-Müller tube, is an instrument designed to detect and measure ionizing radioactivityIt is a fundamental tool in fields such as nuclear physics, nuclear medicine and radiation protection. Its main function is to count ionizing particles, such as alpha, beta and gamma rays, which are emitted by radioactive materials, hence its name: "counter".
Operation
The operation of the Geiger counter is based on a simple but effective principle: the ionization of a gas. To do this, it is made up of the following fundamental parts:
- Geiger-Muller tube: The heart of the meter is a cylindrical metal tube with a central electrode made of fine wire. The space between the cylinder and the wire is filled with a noble gas, such as argon, at low pressure.
- High voltage generator: A high voltage is applied between the cylinder and the wire, creating a strong electric field. When an ionizing particle enters the tube, it collides with gas molecules, knocking off electrons and creating positive ions. The released electrons are accelerated by the electric field and collide with other gas molecules, creating more ions in a process called an avalanche. This electron avalanche produces a brief pulse of electric current that can be detected and amplified by an electronic circuit.
- Counter: The electronic circuit counts these pulses and displays the result on a display, indicating the number of particles detected in a given time interval. That is, each electrical pulse generated by an avalanche represents the detection of an ionizing particle. The electronic circuit counts these pulses and displays them on a display, providing a measure of radioactive activity.
It is important to highlight some additional details, keep in mind that radioactive particles have enough energy to remove electrons from gas atoms, that is, generating positive ions and free electrons. When the released electrons are accelerated by the electric field towards the anode (central wire), during the avalanche, a reaction is generated that continues, which would show a sustained measurement. To avoid this and to make precise measurements at every instant, an extinction process is carried out, preventing the electric charge from becoming continuous. One of the most common practices for this extinction is to add a small amount of halogen gas to absorb the electrons and ions, thus recovering the state of the tube for the next measurement.
Options available to create the Geiger counter with Arduino
Once you know what a Geiger counter is and understand how it works, the next step is to find out how you can Build your own device to measure ionizing radiation your environment easily, cheaply and accurately.
En Amazon has one of these tubes already created, in an Arduino compatible module, which makes things much easier. Also, buying these sensors or tubes separately is not easy and they are expensive, you can find some second-hand ones from the Soviet era on the net, but the best thing is to buy this one:
Also exist interesting kits to assemble, with everything you need, which can be very helpful, and for which you can create your own case using 3D printing so that it has a more compact format and is similar to the commercial ones:
And, if you are a DIY handyman and want solder the components from scratch, you can get this other one:
We will also discuss how to set it up and program it later…