LHC Status / View From CERN

1. 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

2. 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)

3. 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

4. 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

5. 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

6. 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)

7. 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

8. 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

9. 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

10. 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

11. Cool down 2009

12. 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

13. Readiness of the sectors, late October Cool down

14. Revised target for 2009

15. First lead ions in LHC 23.-25. October Injection region screens Mike Lamont TI2/S23 – first trajectory TI2 S23 IT09

16. Trajectory difference before/after precycle IP2 IP3 Reproducibility looks very good IT09

17. Injection region aperture Model Measured BrennanGoddard IT09

18. Injection region trajectories through arc IR3 IR2 IT09

19. First beam to point 7 TI8 S78 In the aperture model IT09

20. Dispersion TI8/S78 Measured v. model TI8 S78 Normalized IT09

21. Kick response IP3 IP2 Problem? Beam Green – Measured Purple - model IT09

22. 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

23. Aperture IT09

24. Proton commissioning (as planned since 2005) (A) 2009 No beam Beam A B 2010 Beam No beam

25. 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

26. 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