Improvement of yield and emittance of ions from an EBIS/T with rf-modulated electron beam

By rf-modulating the current of an electron beam ion source and trap (EBIS/ T) the ion distribution is significantly influenced by the simultaneously m odulated radial trapping potential. It has been observed that highly charge d ions are preferentially accumulated near the axis, showing a substantial reduction of their emittance. Furthermore, by using the appropriate cyclotr on frequency adjusted according to the shift caused by the space charge of the electron beam it is possible to remove ions with specific mass to charg e ratio from the trap. Rf-heating of low charged argon ions during stepwise ionization is enhancing the yield of highly charged argon ions.