Effect of electrode shielding on beamlet-beamlet interaction in multiaperture sources

Extension of previous work on beamlet-beamlet interaction is made in two phases. The effect of beam space-charge truncation due to electrode shielding is considered. For a typical geometry multiaperture source, the ion divergence is thus reduced by a factor of 30, assuming all the beamlets interact with each other, and by a factor of 5, assuming only nearest-neighbor beamlets interact. To account accurately for electrode shielding, a direct solution to the Poisson-Vlasov equation was made for a similar physical situation. For a typical circumstance it shows an additional decrease of a factor of 5 for both the global and nearest-neighbor calculation. These results indicate that beamlet-beamlet interaction is small for typical ion sources.