For the UKRAA PicoMuon, a 16 GB or 32 GB microSD card is generally the best choice.
- Recommended: 16 GB or 32 GB microSDHC
- Speed: Class 10 (or U1) from a reputable brand such as SanDisk, Samsung, or Kingston
- File system: FAT32
- Avoid: Very large cards (64 GB and above) unless you have confirmed they work after reformatting, as these are usually supplied as exFAT and may not be recognised by all Pico-based software.
In practice, a 16 GB card is more than adequate. PicoMuon CSV event files are quite small. Even if you recorded every muon event continuously for months, you would still use only a fraction of the available space. A 32 GB card simply provides extra headroom.
Also remember that before switching the PicoMuon off or removing the card, you should use the “Unmount SD card” menu option to prevent data loss.