XRF

Measuring the metal composition of a coin using X-ray Fluorescence can be useful in identifying counterfeits. This note presents data testing a portable XRF machine on coins in various plastic holders, including a slab. Using the machine’s built-in interpretation shows that very thin plastic films lead to good results, but anything thicker than about 0.1mm produces questionable results and a 1.66mm slab wall is likely to be incorrect.