| Paper |
Title |
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| WEAZ05 |
Very Fast Beam Losses at HERA, and what has been done about it
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beam-losses, luminosity, quadrupole, interaction-region |
215 |
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- K. Wittenburg, M. Werner
DESY, Hamburg
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During the Luminosity upgrade of HERA in 2000/2001 more than 50 new magnets were installed close to the interaction region to provide a stronger focussing of the two beams. Some of these magnets are located at very large values of the betatron function and therefore act with a large gain on the beam. Sudden changes in the power supply currents had led to very fast beam losses, creating quenches and increased radiation levels. This talk will discuss the improvements made to the HERA machine protection system to make sure that the beam is dumped in time in case of these events.
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| WEAZ06 |
Transfer line damage during high intensity proton beam extraction from the SPS in 2004
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extraction, simulation, vacuum, septum |
228 |
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- B. Goddard, V. Kain, V. Mertens, J. A. Uythoven, J. Wenninger
CERN, Geneva
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During extraction of a high intensity beam from the SPS in 2004 an incident occurred in which the vacuum chamber of a transfer line quadrupole magnet was badly damaged. The beam was a 450 GeV full LHC injection batch of 3.4·1013 p+ in 288 bunches, and was extracted with the wrong trajectory. The incident causes have been identified, with details reconstructed from the logged data and the damage to the vacuum chamber. The remedial measures which were taken are explained, and further recommendations made concerning the interlocking system performance and tests, as well as the operational procedures which must be adopted when commissioning with high intensities. The specific issues of how the incident happened, why the existing protection system was not sufficient and what can/has been done about it are addressed.
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