They mean bandwidth as in rate at which one can expose a mask using an
electron beam, because they’ve confused two different technologies. See my other reply.
P.S. Can you usefully chirp an FEL? I don’t know whether the electron sources that would be used for EUV FELs can be re-tuned quickly enough, nor whether the magnet arrangements are conducive to perturbing the wavelength. But relativistic electron beams are weird and maybe it works fine. Of course, I also have no idea why you would want to chirp your lithography light source.
