A segmented Faraday cup for two-dimensional representation of the current distribution of an ion beam

A Faraday cup with 37 segments has been developed to measure the two-dimensional current distribution I=f(x,y) and the total beam current of an ion beam. With an overall cross-sectional area of about 3420 mm2, reproducible current measurements can be carried out down to some nanoamperes. The Faraday cup is used to measure ion beams in an energy range up to 25 keV and beam currents up to 10 mA. The current is determined on the basis of the voltage drop at selected metal film resistors. Initial results confirm good practical applicability in the analysis and adjustment of ion beams.