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LHC Status / View From CERN. Understanding the LHC Interconnects. (Roger Bailey). Status Hardware Commissioning:. nQPS installation Cool down Access matrix and phased powering Schedule. Sector tests. (Mike Lamont). Commissioning plans for 2009.
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LHC Status / View From CERN Understanding the LHC Interconnects (Roger Bailey) Status Hardware Commissioning: • nQPS installation • Cool down • Access matrix and phased powering • Schedule Sector tests (Mike Lamont) Commissioning plans for 2009 CM13 in Port Jefferson; 4. to 6. November 2009 Oliver Brüning/CERN AB-ABP 0
Machine wide investigations at cold Q4 2008 • Controlled calorimetric measurements at cold where possible • Measured heat loads indicated problem areas • Measure electrical resistance in suspect regions • Electrical resistance of joints between and inside magnets • Fix anything obviously very wrong (means warming up)
Investigations in sector 34 Q1 2009 Bad surprise after gamma-ray imaging of the joints Void is present in bus extremities because SnAg flowed out during soldering of the joint
Calorimetric & electrical measurement summary Made wherever possible in late 2008 Sectors 23 34 45 already not cold Sectors 12 56 67 78 81 measured Identified 3 suspicious cases (in magnets) Sector 12 – 15R1 – confirmed Sector 12 – 31R1 – not confirmed Sector 67 – 31R6 – confirmed S34
Decisions Q1 2009 Sector 34 repair Restart • Decided to warm up in 12 and 67 to replace faulty magnets • Decided to warm up sector 56 in parallel for other reasons • Warming up means • 3 weeks to get to 300K • Repair work • ELQA and other issues • 6 weeks to get back to 2K
Machine wide investigations Q2 2009 • Electrical measurements at warm on sectors 12 34 56 67 • Confirms new problem with the copper stabilizers • Non-invasive electrical measurements to show suspicious regions • Several bad regions found • Open and make precise local electrical measurements • Several bad stabilizers found (30µΩ to 50µΩ) and fixed • Measured other 4 sectors at 80K (noisy but gives limits)
Machine wide activities Q4 2008 and 2009 Sector 34 repair Restart • Electrical splice measurements everywhere at cold (measuring nΩ) Q4 2008 • Had to warm up sectors 12 56 67 • Electrical stabilizer measurements everywhere at warm or at 80K (measuring µΩ) Q1 Q2 2009 • Had to warm up sector 45 • Major new protection system based on electrical measurements Q1 – Q4 2009 (nQPS) • Pressure relief valves installed everywhere possible Q1 – Q3 2009 (dipoles have to be warm) • Reinforcement of floor anchors everywhere Q1 – Q3 2009
Measurement summary Q3 2009 • 5 sectors measured at cold for splices • 12 56 67 78 81 • Nothing above 40 nΩ remaining • 23 34 45 not measured • Data mining finds nothing > 25nΩ (in 99% of 23 34 45) • 5 sectors measured at warm for stabilizers • 12 34 45 56 67 • All above 50µΩ fixed • 23 78 81 measured at 80K • Nothing above 90µΩ remaining
Energy • Putting all this together • Splices • 5 TeV OK • Stabilizers • 3.5 TeV OK • Higher energies needs operational experience to see which model variant most closely matches reality • 90µΩ limit is very conservative • Start at 3.5 TeV • Operate • Move to 5 TeV when experience allows it
Quench Protection System upgrade (nQPS) • New QPS to provide • Protection against symmetric quenches (problem noticed in summer 08) • Local bus bar measurements capable of detecting bad splices • Will also provide • Precision measurements of the joint resistances at cold (sub-nΩ range) of every busbar segment • complete mapping of the splice resistances (the bonding between the superconducting cables) • The basic monitoring system for future determination of busbar resistances at warm (min. 80 K) • measure regularly the continuity of the copper stabilizers • Huge task • Has to be working before repowering (recommendation of external review) • On the critical path for restart • Requires extensive testing LHC Enhanced Quench Protection System Review
SD2: Conditions for working at height SD1: Conditions for working at height Access to ALICE subject to conditions Access to ATLAS subject to conditions SMI2: Conditions for working at height
Readiness of the sectors, late October Cool down
First lead ions in LHC 23.-25. October Injection region screens Mike Lamont TI2/S23 – first trajectory TI2 S23 IT09
Trajectory difference before/after precycle IP2 IP3 Reproducibility looks very good IT09
Injection region aperture Model Measured BrennanGoddard IT09
Injection region trajectories through arc IR3 IR2 IT09
First beam to point 7 TI8 S78 In the aperture model IT09
Dispersion TI8/S78 Measured v. model TI8 S78 Normalized IT09
Kick response IP3 IP2 Problem? Beam Green – Measured Purple - model IT09
Sunday – Walter starts early… Collimator scan H Non-closure of LHCb dipole and compensators with LHCb dipole at full field (rms ~ 1 mm) V Beam IT09
Aperture IT09
Proton commissioning (as planned since 2005) (A) 2009 No beam Beam A B 2010 Beam No beam
Targets with beam 2009 Do this with safe beams 1012 at 450 GeV → 2 1011 at 1.1 TeV, 3 1010 at 3.5TeV LIMIT 2 on 2 with 5 1010 per bunch at 1.1 TeV 2 on 2 with 1010 per bunch at 3.5TeV
Christmas break • Stop LHC with beam • ~17th December 2009, restart ~ 7th January 2010 • Cryogenics: • 2 days to set-up 3 K for Christmas • 3 days on return to re-establish 1.9 K • Coverage over stop - details to be finalized • All machines on standby except for • Essential maintenance work on LHC will be performed during the stop • Essential maintenance work on injectors will be performed during the stop