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LHC Status Lyndon R. Evans LHC 2003 / 4th International Symposium on LHC: Physics and detectors FNAL, 1-3 May 2003. Civil Engineering at Point 1. Civil Engineering at Point 5. Civil Engineering. All excavation finished. Caverns will be delivered on schedule:
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LHC Status Lyndon R. Evans LHC 2003 / 4th International Symposium on LHC: Physics and detectors FNAL, 1-3 May 2003
Civil Engineering • All excavation finished. • Caverns will be delivered on schedule: • ATLAS 15th April 2003 CMS 1st July 2004 • LHC machine – all CE finished by summer 2003.
Dipole Production • Dipole production is ramping up according to plan. • CERN-provided components are being stockpiled at a numberof sites. • Cable production is now at nominal rate after the commissioning of the new cabling machine.
Main Quadrupoles • Saclay-CERN collaboration. • Two quadrupoles tested, excellent results. • Quadrupole #11 finished. • One complete cold mass delivered, second in pressure test, #3 and #4 under construction. • Main bottleneck is delivery of correctors, in particular MSCB.
Insertion Magnets • US and Japanese insertion quadrupoles are now well into production and give excellent results. • Integration into the inner triplet assemblies at FNAL. Some delays in CERN-supplied correctors. • The first beam separation dipole has arrived from BNL.
Electrons, from synchrotron radiation or ionisation, can be accelerated in the potential well of the bunches, creating secondaries on impact with the beam screen. For 25 nsec bunch separation, this can result in an exponential build-up and is a source of heat input into the cryogenic system. Electron bombardment has a “scrubbing” effect, reducing the SEY and increasing the threshold. This has clearly been observed in the SPS. Electron Cloud Effect
Simulations (Zimmermann et al.) now predict many features that can be verified experimentally. In the warm regions, the chamber will be coated with a new getter materail, TiZrV (Benvenuti) that activates at much lower temperature (200° C) than conventional getters. Once activated, the SEY is low enough to avoid e-cloud build-up. Electron Cloud Effect
Cryogenics • AL 18 kW plants at points 4 and I8 commissioned and accepted. Linde plants at points 6 and 8 ready for commissioning. • IHI/Linde 1.8 K compressors in production (four units). AL prototype under final acceptance. • QRL (distribution line) on schedule to start installation 16th June. • Cryogenic feedboxes for magnet test stations, delivery of 3rd and 4th units mid-April.
Conclusion • The experimental areas and infrastructures will be deliveredon time. • The LHC machine construction is on schedule for start-up with beam in April 2007.