(a) SEM image of some zircon grains. (b) Panchromatic PMT intensity image (grayscale) of the same area. (c) Close-up panchromatic PMT image of a single zircon grain. These measurements were taken at 10 kV acceleration voltage and 1 nA current with a 100 µs dwell time. CL images took ~1.5 minutes to collect. Samples courtesy of Prof. Jens Jahren (University of Oslo).