This project is unfinished.
Cosmic radiation is a constant stream of high energy particles from deep space, when they arrive on Earth they collide with atmosphere's atoms. Due to theirs high-speed (near light speed), during those collisions a lot of particles are made, one of them are muons that can be observed with Geiger tubes.
Earth has its own background radioactivity level and this would add to the measured muons, but there is a trick. Muons have high energy, so they will pass through Geiger tube (this will be detected) and won't be stopped, if near there is another Geiger tube they will pass through it as well (and it will be detected too). Radioactive particles from earth won't do that, they don't have enough energy.
This device has a grid of Geiger tubes and analyzes if a particle went through many of them, if yes, it's probably a muon, if no, it's background radiation. To help minimize background radiation, lead shielding will be placed around Geiger tubes.
There are similar projects around Internet, but they all have analog interface, this one is aiming to have digital processing, so that it will be possible to present results in more readable form, or to analyze them further on PC.
On the center of above image is visible a grid of 4x4 Geiger tubes. On the left and right sie are four stacked PCBs that are connected to GM Tubes. Those PCBs on the left contain A/D converters and are connected to FPGA board visible on top left side of the image. Those on the right side are used as connector between GM tubes, and high voltage generator, that is visible on top right side. In front of the image, on the left is visible a PCB of a display.
Parts for 3D printing and model of the whole device were designed in OpenSCAD. Above renderer was done in Blender.
To decrease manufacturing costs, the same PCB is used as:
- A/D converter.
- Connector between GM tube and high voltage generator.
- User interface.
Render above show top side of fully assembled PCB, however in real device, depends on PCB usage, only some components will be placed (e.g. no need for GM tube holder in PCB used as a display) [more info].
- DC/DC converter from this Geiger-Muller counter was used as a source of high voltage.
- Geiger tube model is STS-5 (СTC-5)
PCB was designed in KiCAD.
- FPGA (Cyclone IV) firmware will be written in verilog using QuartusLite as IDE.
- Setting up development environment on Windows
- The device uses high voltage and can lead to unpleasant shock, injury or death. Don't touch the PCB or tubes when power is on.