4 Channel Geiger-Mueller Counter for Low-Dose Long-Term Measurements

The project has been born from the idea to revive an old Geiger-Mueller circuit built in the 80s by the author and to make use of some semiconductor radiation detectors.

Furthermore, the final solution shall be able to execute long-term measurements to detect weak radiation just above the background.

The VA-Z-118 Geiger-Mueller tube generates 320 +/-10% counts per minute at 1µSv/h, wheras the semiconductors provide very low counts of around 6/min (RD2014) and 3.8/min (RD2007) for the same dose rate.

A Pi Zero instead of a microcontroller was chosen just because of the laziness of the author to do the software development within one weekend by using Python 3.

The black & white OLED-Display (SH1106) can be easily controlled via the Python library versions of luma.oled and luma.core.

Features:
It is possible to skip with a single button through the different views:
1.) All 4 channels
2.) Single channel (0 – 3)

Learning:
Selecting the RPi.GPIO library to count in real time impulses on the GPIO input by using the callback mechanism on a none realtime OS is not really perfect and the author of that library clearly states that it is far better to go under those circumstances for a microcontroller.
Putting the callback in its own process helps, but nevertheless it would make sense to add a microcontroller in the next project step to handle the realtime work.

In part 2 a microcontroller (ARDUINO UNO) has been added: Part 2 of the 4 Channel Geiger Mueller Counter for Low-Dose Long Term Measurements