Design study of the SPS beam dumping system

An internal beam dumping system is needed for the SPS, in order to prevent uncontrolled loss of the beam in the accelerator. Several possible dumping schemes have been studied and compared in Ref. (1), and the method using fast kicker magnets has been chosen. The beam dumping system will use a pair of kicker magnets, which deflect the beam verti-cally onto the absorber blocks, and the beam will be dumped in one SPS revolution. It has been shown$^{(1)}$ that dumping a ow emittance beam of 10$^{13}$ ppp at 400 GeV/c leads to severe thermal problems in the absorber blocks. In particular, dumping the beam with fast kickers induces in the absorber blocks instantaneous temperature rises. These depend on the proton density distributions in the beam and the material used for the block and can be at least as high as l000$^{°}$C in case of aluminium. Although the values of these temperature spikes cannot be calculated with good accuracy, they are certainly higher than permitted for a reliable absorber block design. It is not possible to blow up the beam before the dumping process starts in order to reduce these spikes,as this is not compatible with a fast emergency beam dumping system. It is therefore necessary to spread the beam over the front surface of the absorber block during the 23 µs long dumping process.