A super-EBIT may be defined by its ability to ionize even hydrogenlike
uranium, requiring an electron energy well above 140 keV. The first s
uper-EBIT has been put into operation at Livermore, operating with ele
ctron energies up to 200 keV, the second one is in progress in Tokyo,
aiming at 300 keV. A distinctive advantage may be obtained by raising
the electron energy from 200-300 to 500 keV, thus reducing the radiati
ve recombination of hydrogenlike heavy ions such as U91+ and increasin
g their relative abundance by an order of magnitude. (C) 1996 American
Institute of Physics.