You're right, I stand corrected. This page [0] has an image of a small scintillator plus photomultiplier, but probably too thick for a phone. [0]https://scan-

You're right, I stand corrected. This page [0] has an image of a small scintillator plus photomultiplier, but probably too thick for a phone. [0]https://scan-electronics.com/en/dosimeters/radiacode-101 https://scan-electronics.com/en/dosimeters/radiacode-101