Now that's a toy you don't stumble across very often! Not sure what I'd do with it, but others may have a use: https://www.radiacode.com/
Radiacode – Portable Radiation Detector, Dosimeter & Spectrometer

Radiacode is a fast, portable radiation detector, dosimeter, and spectrometer with real-time analysis. 20× faster than Geiger counters, it identifies isotopes, tests food for contamination, and supports research and safety.

@cstross I think aranet makes one too

https://aranet.com/en/home/products/aranet4_aranet_radiation

It connects to home assistant which is great.

Aranet

@domo @cstross Not being familiar with detectors I'm curious how their sensors compare.