Accelerator Engineering and Physics for Heavy-Ion Synchrotron (1^st Part) ―Power Supply for Magnets: A Battle against Common-Mode Noise―

Abstract

Power supplies of thyristor–rectifier type for electric strings of magnets of HIMAC synchrotrons are characterized by high stability and nice reproducibility in addition to low noise. Excellent power supplies result in stable acceleration without beam feedback due to high performance of 2 ppm for dc without such an active filter as a series dropper and 0.3 ppm for ac with an active filter of reactor-transformer type. A special electrical configuration of both power supplies and electric strings of magnets is based on separation of normal mode and common mode, both of which were found in existing machines of other laboratories in Japan. In this way a static filter for common mode in addition to that for normal-mode is very effective in suppressing noise for both dc and ac.