There are many useful things you can do with a Raspberry Pi Pico (opens in new tab), as our listing of the best Raspberry Pi Projects (opens in new tab) underlines. However, here’s one we admit we’d never thought of: detecting radiation. Physicist Matthias Rosezky, AKA Nuclear Phoenix (opens in new tab), whose work has also been covered by Hackaday (opens in new tab), has written up a detailed account of building a DIY gamma-ray spectrometer in IEEE Spectrum (opens in new tab).
The device acts a little like a Geiger counter but is more sensitive and can identify the exact combination of isotopes that makes the detector click. Rosezky described the Pico as the ‘natural choice’ for a microcontroller when creating this project. He purchased a small sodium iodine crystal from eBay for $40 and combined it with a silicon photomultiplier. All this was connected to a carrier board, into which the Pi Pico was inserted. A gamma ray produces an electron with proportional energy in the crystal, which excites the atoms as it moves through the structure. This causes photons – light – to be emitted, and by counting the photons, you can know the energy of the gamma ray.
Known as the Open Gamma Detector (opens in new tab), the aim behind the project is to keep the price down, as the devices can cost over $1,000 if purchased from a lab supplier. Measuring just 6cm x 6cm (2.3in square), the custom detector PCB makes up most of the device’s area, as the Pico itself slots into it.