Is there any reason they couldn't chain a whole bunch together to kick up to higher energy levels? Say you need 50um per segment for the support framework and whatnot, you could pack 200 of them in a cm long instrument and kick up the power by 200keV?
The design shown in this paper is specific to an initial electron energy of 83keV. That means that chaining identical parts wouldn't work, but you could have an array of similar parts with slightly different properties at each "stage".
