EFFECT OF CURRENT RIPPLE OF POWER-SUPPLIES ON ELECTRON-BEAM IN SYNCHROTRON

The effect of current ripple of quadrupole magnet power supplies has been studied from measurements and calculations in an electron synchrotron situated Mitsubishi Electric Corporation. The effect has been unexplainable as a quasi-static tune shift. The effect can be simulated fairly well with beam tracking in which the injection beam size and momentum spread are taken into account. Measured and calculated results have shown that the allowed current ripple of quadrupole defocus magnet (QD) where nu(x) = 2.26 and nu(y) = 1.18, is about +/-0.6% in the synchrotron when 20% beam loss is permitted. A calculation has proven that compensation of chromaticities can reduce the effect when the momentum spread of the injection beam is large.