Measurements of space charge compensation of ion beams

Abstract

Slow ‘residual gas ions’ (RGI) are repelled from the space charge of an ion beam which is passing through the residual gas in a beam transport system. To measure the energy distribution of these ions an electrostatic analyzer combined with a position sensitive channel plate detector has been used. Measurements have been performed with beams of Ar + ions in the energy range between 15 and 45 keV with beam currents ranging from 0.01 up to 1.6 mA under different experimental conditions (residual gas pressure, beam diameter, potentials of electrodes along the beamline, pulsed beams). The mean energy of the residual gas ions varies between 0 and 70 eV.