CERN, Geneva
Uni HH, Hamburg
The 7 km long CERN Super Proton Synchrotron (SPS) is, apart from the LHC, the accelerator with the largest stored beam energy worldwide of up to 3 MJ. In 2008, an equipment failure led to a fast tune shift towards an integer resonance and an uncontrolled loss of a high intensity beam, which resulted in major damage of the accelerator. Distinct experimental studies and simulations provide clear understanding of the beam dynamics and the beam loss pattern at different SPS tune resonances. Diverging closed orbit oscillations, a resonant dispersion and increased beta beating are the driving effects that lead to a complete beam loss in as little as 3 turns (69μs). At the moment, the commissioning of a new turn-by-turn position interlock system which will counteract the vulnerability of the SPS is ongoing.
