Less than 10 meV MTE from Cu
S. Karkare, et al.
The brightness of electron beams is limited by the smallest possible mean transverse energy (MTE) of
electrons emitted from the photocathode. There are various factors that limit MTE and CBB is working to minimize each of these factors. Upon doing this, we obtained a record low MTE of 6 meV from the (100) surface of Cu. Before now, there was no instrumentation to even measure MTE this low, so we developed the technology to do this. We have not stopped, and there are various ongoing efforts within the Center for Bright Beams to obtain such small MTE along with large charge densities to increase the brightness of electron beams by two orders of magnitude.