Power supply system for a compact 1.2 GEV booster synchrotron

Low cost power supply system for compact fun energy booster synchrotron was designed, developed and successfully commissioned at Duke University. 500kW second hand thyristor controlled power supply has been completely rebuilt to provide high accuracy ramping of current in the range between 150A and 700A in a 1.3 sec repetition cycle. Reproducibility of current at injection and extraction energy of better than 0.2% was achieved. Conflict of requirements of a fast ramp operation and a magnet protection in the case of emergency shutdown was resolved by means of additional thyristor switches. All him power supplies involved in ramp have been matched with main power supply for the time response and voltage range. Vertical injection to and extraction from the booster requires a strong Y-bump. Combination of low voltage DC power supply and pulse boosting circuit has eliminated the need of expensive power supply for peak power about 4 kW. Challenges of design, main parameters of the booster power supply system and discussion of operation experience are presented in this paper.