Energy stabilization of a 4-MeV electrostatic accelerator using controlled corona discharge

Beam energy is stabilized by detecting beam displacements, due to potential changes at the high voltage terminal, on a horizontal slit situated at the exit of the electrostatic analyser. Differential currents, due to off-centring of the ion beam on this slit, are amplified and used to control the magnitude of corona discharge loading via the corona triode. Thus beam movements alter the loading on the generator and so regulate its output voltage. This system controls the energy of the particles emerging from the exit of the electrostatic analyser to an accuracy of one part in 103 over long periods.