Bonn 2010 – scientific programme
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T: Fachverband Teilchenphysik
T 80: Beschleunigerphysik III
T 80.1: Talk
Wednesday, March 17, 2010, 14:00–14:15, HG ÜR 4
Tune resonance phenomena in the SPS and machine protection via fast position interlocking — •Tobias Bär1,2,3, Jörg Wenninger1, Thierry Bogey1, and Berta Araujo Meleiro1 — 1CERN, Genf, Schweiz — 2Universität Hamburg, Deutschland — 3DESY, Hamburg, Deutschland
The 6911m long Super Proton Synchrotron (SPS) at CERN with a peak energy of 450GeV is at the top of the LHC preaccelerator-complex. Apart from the LHC, the SPS is with the Tevatron the accelerator with the largest stored beam energy of up to 2.5MJ. The SPS has a known vulnerability to fast equipment failures that led to an uncontrolled loss of a high intensity beam in 2008, which resulted in major damage of a main dipole. The beam loss was caused by a fast tune decrease towards an integer resonance. Simulations and distinct experimental studies provide clear understanding of the beam dynamics at different SPS tune resonances. Diverging closed orbit oscillations, dispersion explosion and increased beta-beating are the driving effects that lead to a complete beam loss in as little as 10 turns (230μs) after reaching the stop band of the resonance. Dedicated experiments of fast failures of the main power converters reveal that the current interlock systems with a delay of 7-12ms are much too slow for an adequate machine protection. To counteract the vulnerability of the SPS, current research focuses on a new fast position interlock system which is planned to become operational in the first quarter of 2010.