The New Broadband Accelerating System for the SIS18 Upgrate at GSI

This paper describes a new complete RF accelerating system whose cavities are based on novel MA-materials (magnetic alloy materials). It describes cooling issues, the cavity, the power amplifier, the supply units and the lowlevel system. The RF system works at harmonic number h=2 (f=0.43to 2.8 MHz) and provides the necessary accelerating voltage for SIS18 injector operation with high intensity heavy ion beams in a fast operation mode with about three cycles per second. The acceleration system consists of three units which are able to operate independently from each other. That is important, since each ion for FAIR [1] has to cross the h=2-RF-system and in the case of a damage a reduced operation has to be ensured. Due to the lossy MA-ring-core-filling the cavities show a broadband behaviour and thus no cavity tuning during the acceleration ramp will be necessary. Due to the high saturation field strength of the magnetic alloy the overall length of all three cavity units can be very short (< 4m).