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LHC status and commissioning plans

LHC status and commissioning plans. LHC in 4 slides Lest we forget Progress to date Present schedules Consequent plan for 2008. LHC dipoles (1232 of them) operating at 1.9K. 7TeV 8.33T 11850A 7MJ. And plenty more magnets besides …. Several thousand magnets.

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LHC status and commissioning plans

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  1. LHC status and commissioning plans

  2. LHC in 4 slides Lest we forget Progress to date Present schedules Consequent plan for 2008

  3. LHC dipoles (1232 of them) operating at 1.9K • 7TeV • 8.33T • 11850A • 7MJ R.Bailey, DESY, December 2007

  4. And plenty more magnets besides … Several thousand magnets • Thousands of Interconnects • Electrical • Fluids • Vacuum R.Bailey, DESY, December 2007

  5. And plenty of power circuits … Several hundred Power Circuits R.Bailey, DESY, December 2007

  6. Lest we forget – QRL • Installation started in sector 7-8 in July 2003 • Geometry, weld quality, procedures, leaks, support tables … • Installation finished November 2006 (sector 78 by CERN) R.Bailey, DESY, December 2007

  7. Lest we forget – Main magnets • First magnet installed March 2005 • Peak of ~1000 dipoles stored, allowed magnet sorting • Last dipole lowered April 26th 2007 • Cryostating 425 FTE . years • Cold tests 640 FTE . years • Transport 30’000 km underground at 2 km/h! R.Bailey, DESY, December 2007

  8. Lest we forget – Triplets – Heat exchanger problem • During the pressure test of Sector 7-8 (25 November 2006) the corrugated heat exchanger tube in the inner triplet failed by buckling at 9 bar (external) differential pressure. • The inner triplet was isolated and the pressure test of the whole octant was successfully carried out to the maximum pressure of 27.5 bar, thus allowing it to be later cooled down. • Reduced-height of corrugations and annealing of copper near the brazed joint at the tube extremities accounted for the insufficient resistance to buckling. • New tubes were produced with higher wall thickness, no change in corrugation height at ends, and e-beam welded collars to increase distance to the brazed joint. • Installation of these tubes was made in situ. R.Bailey, DESY, December 2007

  9. Lest we forget – Triplets – Supports problem Q1 supports at IP 5L On Tuesday March 27 2007 there was a serious failure in a high-pressure test at CERN of a Fermilab-built “inner-triplet” series of three quadrupole magnets R.Bailey, DESY, December 2007

  10. Lest we forget – Triplets – Supports solution • Requirements for repair • Must be implemented in situ • Does not displace the fixed points of the assembly • React loads with sufficient stiffness to limit deflection at 150 kN design load • Acts at any temperature between 300K and 2K • To be implemented in Q1 and Q3 • Solution adopted • Affixed at Q1 non-IP end and at Q3 IP end • Transfer load at all temperatures • Limits support deflections • Compound design with Invar rod and aluminium alloy tube • Attached with brackets to cold mass and cryostat outer vessel • Status • All triplets repaired by September • Problem solved R.Bailey, DESY, December 2007

  11. 18kV for the dipole circuits 400V for the others UPS for all converters above 4 kA PC UA, UJ, RR DCCT Water Short Circuit tunnel, UJ Commissioning of the power converters 1720/1720 installed Commissioning campaign on short circuit From mid 2006 to late 2007 100% commissioned R.Bailey, DESY, December 2007

  12. Machine commissioning without beam is by sector 8 distinct sectors for cryogenic and powering Picture today Order was originally determined by installation sequence 78 81 45 34 56 67 23 12 R.Bailey, DESY, December 2007

  13. Shielded bellows on the cold interconnects (PiMs) R.Bailey, DESY, December 2007

  14. Plug in Module in equivalent cold position R.Bailey, DESY, December 2007

  15. Polycarbonate shell Diameter 34mm exterior 30mm interior Total weight ~15 g (ball 8g) RF characteristics 40MHz resonantcircuit Generates 20V between copper electrodes Battery powered Over 2hr lifetime Capacitive coupling to BPM electrodes 1V ⇒~5mV -45db Coupling BPM trigger threshold at ~3mV RF mole R.Bailey, DESY, December 2007

  16. Commissioning of sector 45 (without triplet) Leak to insulating vacuum Stop for repair Water in the oil of Compressor station Almost ready for powering Leak to insulating vacuum Stop for repair R.Bailey, DESY, December 2007

  17. Beam tests October 2004 October 2007 R.Bailey, DESY, December 2007

  18. Performance goals • Nearly all the parameters are variable • Number of particles per bunch  • Number of bunches per beam kb • Relativistic factor (E/m0)  • Normalised emittance n • Beta function at the IP  * • Crossing angle factor F • Full crossing angle c • Bunch length z • Transverse beam size at the IP * “Thus, to achieve high luminosity, all one has to do is make (lots of) high population bunches of low emittance to collide at high frequency at locations where the beam optics provides as low values of the amplitude functions as possible.” PDG 2005, chapter 25 R.Bailey, DESY, December 2007

  19. Overall commissioning strategy for protons (estd. 2005) Stage A D B C No beam Beam • Pilot physics run • First collisions • 43 bunches, no crossing angle, no squeeze, moderate intensities • Push performance • Performance limit 1032 cm-2 s-1 (event pileup) • 75ns operation • Establish multi-bunch operation, moderate intensities • Relaxed machine parameters (squeeze and crossing angle) • Push squeeze and crossing angle • Performance limit 1033 cm-2 s-1 (event pileup) • 25ns operation I • Nominal crossing angle • Push squeeze • Increase intensity to 50% nominal • Performance limit 2 1033 cm-2 s-1 • 25ns operation II • Push towards nominal performance R.Bailey, DESY, December 2007

  20. LHCb during Stage A • Displace bunches in one ring (n on m) • 4 per SPS cycle in 43 bunch, 16 per SPS cycle in 156 bunch mode • Dedicated runs for LHCb (n on n) ? • Squeeze in point 8 (2m limit for ‘bad’ LHC dipole polarity) • All values for • nominal emittance • 7TeV R.Bailey, DESY, December 2007

  21. Stage B physics run • Relaxed crossing angle (250 rad) • Start un-squeezed • Then go to where we were in stage A • All values for • nominal emittance • 7TeV • 10m * in points 2 and 8 (will not be like this) Protons/beam ≈ few 1013 Stored energy/beam ≤ 100MJ R.Bailey, DESY, December 2007

  22. Stage C physics run • Nominal crossing angle (285 rad) • Start un-squeezed • Then go to where we were in stage B • All values for • nominal emittance • 7TeV • 10m * in points 2 and 8 (will not be like this) Protons/beam ≈ 1014 Stored energy/beam ≥ 100MJ R.Bailey, DESY, December 2007

  23. Stage A: routes through the commissioning phases Snapback Ramp Injection First turn Snapback Ramp Top energy checks Injection First turn Circulating beam Top energy checks Squeeze Circulating beam 450GeV initial Squeeze 450GeV initial 450GeV optics Ramp both beams Experiment magnets OFF 450GeV optics 450GeV Increase I Squeeze both beams Top energy Collisions 450GeV Increase I Dipoles OFF 450GeV 2 beams Beam 2 Pilot physics Beam 1 450GeV Collisions 2 beams R.Bailey, DESY, December 2007

  24. Beam commissioning to 7 TeV collisions R.Bailey, DESY, December 2007

  25. Stage A: First collisions • Approx 30 days of beam time to establish first collisions • Un-squeezed • Low intensity • Approx 2 months elapsed time • Given optimistic machine availability • Continued commissioning thereafter • Increased intensity • Squeeze R.Bailey, DESY, December 2007

  26. Staged commissioning plan for protons 2008 A No beam Beam 2009 B C No beam Beam R.Bailey, DESY, December 2007

  27. First beam Beam 2 Beam 1 R.Bailey, DESY, December 2007

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