4 ms·
Presumably because verifying the composition of the entire coin without destroying it is a very hard problem.
by sirsar 13y ago
Presumably because verifying the composition of the entire coin without destroying it is a very hard problem.
- mindslight 13y agoChoose the element based on physical properties that are easy to non-intrusively verify - maybe the most dense, non-radioactive, malleable.. Joking aside, I once worked on a device to detect double-photon fluorescing marker that's probably similar to what they're using, once again aimed at anti-counterfeiting of various things. It's pretty neat to hit a substance with IR and have it glow green, and I haven't seen anything similar since. I still wonder how rare/common substances with this effect actually are versus their marketing spiel.