The power supply for a medical synchrotron Beam Chopper System

In this paper the power supply for the Beam Chopper System of a medical synchrotron is presented. The four, series connected beam chopper magnets, which are placed on the extraction line, are used for blanking the beam both during routine operation and for emergency. To let the beam pass the magnets need to be energized with a current, proportional to the beam energy, whose maximum value is 650 A. Rise and fall time shall be less than 260 mus, while the flat-top can be maintained for an arbitrary long time. The power supply is composed of an high voltage part, which is in charge of the rising and falling current ramp, and of a low voltage part, which is in turn responsible for the current flat top. The paper presents details about the design and experimental results measured on the actual device.