Chamonix 09 Highlights

1. Chamonix 09 Highlights J. Wenninger BE-OP Chamonix 09 Highlights

2. Chamonix 2009 program – 9 sessions • What did we learn without beam in 2008– R. Saban • Safety – R. Trant • Repair of 34 – R. Schmidt • Strategy for consolidation to avoid incident and limit collateral damage – A. Siemko • Shutdown Modifications 2008/9 and Future shutdowns – S. Baird • What else can go wrong – J. Wenninger • What did we learn with beam in 2008? – M. Lamont • What we will do for beam preparation in 2009 – G. Arduini • What will we do with beam in 2009/10 – R. Bailey Chamonix 09 Highlights

3. Warning ! • This is not the official summary of Chamonix 2009. • >> Official summary is Tuesday 24th February. • This presentation is a summary of highlights that may be of interest to ‘users’ like you. Chamonix 09 Highlights

4. Contents • Sector 34 incident • Vacuum repair • Pressure relief improvements • Magnet repair • Magnet training to 7 TeV • Cryogenics • Machine protection • Scheduling & physics runs Chamonix 09 Highlights

5. Sector 34 Incident Presentations by P. Lebrun, A. Verweij Chamonix 09 Highlights

6. For your eyes only !THE Electrical arc between C24 and Q24 V lines M3 line M3 line = dipole busbar Chamonix 09 Highlights

7. Displacements QBQI.27R3 Bellows torn open QBBI.B31R3 Extension by 73 mm Chamonix 09 Highlights

8. Secondary arcs due to extensions QBBI.B31R3 M3 line QQBI.27R3 M3 line Chamonix 09 Highlights

9. No electrical contact between wedge and U-profile with the bus on at least 1 side of the joint No bonding at joint with the U-profile and the wedge Resistive joint model • Loss of clamping pressure on the joint, and between joint and Cu stabilizer. • Degradation of transverse contact betweensuperconductingcable and Cu stabilizer. • Interruption of longitudinal electricalcontinuity in Cu stabilizer. Chamonix 09 Highlights

10. Simulation of incident with 220 nW Chamonix 09 Highlights

11. Bus-bar voltage: simulation vs measurements Quench trigger threshold : 1 V Chamonix 09 Highlights

12. Energy balance

13. Future incident prevention • New quench detection system for all dipole joints. The threshold must be set 0.3 mV to cover entire range down to joint resistances of 25 nW (so far 1 V for entire busbar). Possible with ‘heavy’ filtering… • >> Electronics & cables in production.. • The new system would have prevented 19th Sept, and will be able to prevent incidents if there are ‘pre-cursors’ like on 19th Sept, but it will never protect against a bus-bar that ruptures suddenly. • Clamping joints : ideal, but no good solution so far (space constraints). • Pressure relief systems (see later) can only reduce the ‘collateral’ damage! Chamonix 09 Highlights

14. Status of other sectors – suspicious resistances (1) suspected cases from calorimetric measurements 1 confirmed cases by electrical measurement. Old SM18 test data analysis : no clear if it will yield useful data !

15. Vacuum Repair Presentations by V. Baglin Chamonix 09 Highlights

16. Vacuum All beam lines in the tunnel have been inspected. (MLI : Multi Layer Insulation) Chamonix 09 Highlights

17. Beam vacuum contamination Chamonix 09 Highlights

18. Soot cleaning in tunnel • Two separate cleaning heads for horizontal and for vertical parts of the beam screen. • Up to 50 passages in each direction with wet foam (alcohol). • Up to 15 passages with dry foam. Chamonix 09 Highlights

19. MLI removal • First step:pumping/venting of one half-cell (52 m) • Each cycle : 20 s pumping, 18 s plateau, 2 second vent. • Applied for 30 min (40 pumping/venting cycles), repeated 5-10 times • Second step:a nozzleblowsfiltered air, the MLI residuesleftbehind the beamscreen and the RF fingers are directedtowards the beam aperture wherethey are pumped. • Takes ~ 30 minutes per half-cell, repeated 5-10 times. Chamonix 09 Highlights

20. Vacuum summary • In-situ cleaning works well and everything will be cleaned. • There are however residues of sooth and MLI behind the beam screen and in the bellows (PIMS). Probably OK… Chamonix 09 Highlights

21. Pressure release systems Presentations by V. Parma (and others) Chamonix 09 Highlights

22. Simplified sub-sector schema Chamonix 09 Highlights

23. Present relief valves (on quadrupoles) • Designed for He flow of 2 kg/s • Estimate for incident is ~ 20 kg/s Chamonix 09 Highlights

24. MCI • The (new) “Maximum Conceivable Incident” (MCI) was identified as rupture of all enclosures connected to the magnets. • >> He flow of 40 kg/s • To mitigate against the collateral damage to the interconnects and the super-insulation under the MCI conditions (max pressure of 1.5 bar), additional relief valves (200mm diameter, ‘DN200’) must be installed on all dipole magnets. Add SSS valves. Add SSS valves +DN200. Please don’t forget the vacuum !! Chamonix 09 Highlights

25. SV SV SV SV SV Cold sectors, temporary relief system New Existing • Keep existing 2 DN90 relief devices • Mount relief springs on 5 DN100 vac. flanges • Mount relief springs on 8 DN100 BPM flanges • Mount relief springs on 4 DN63 cryo.instr. flanges •  Cross section increase: x 10 Chamonix 09 Highlights

26. DN200 relief valves on dipoles • Warm sectors will be equipped in-situ with DN200 relief valves on each dipole. • It seems technical issues are solved (risk of ignition due to hot ‘schips’ etc). Chamonix 09 Highlights

27. Oxygen content at ceiling No significant deficiency In UJ4x Chamonix 09 Highlights

28. Safety • Following the incident the safety issues related to He are reanalyzed. • Issues: • Safety during powering tests. So far limit for presence of people (=experts) was limited to 1 kA (max is 13 kA for dipoles/quads). New ‘reasonable’ approach being defined… • Large release close to experimental caverns. Can it come from both sides? • Issue of the warm He ‘transfer line’, used to transfer He from one point to another: can be in service even if the sector is warm ! • … Chamonix 09 Highlights

29. Magnet Repair Presentations by L. Rossi Chamonix 09 Highlights

30. Status of dipoles on 19th September • DIPOLES : 46 ordered in addition to the 1232 for tunnel • However 6 were (are) not available: • 1 lost during production (MB1005, bad cable) • 1 under repair (MB-2001) because pole or inter-layer splice not conform. This s the first action as MAR (started in Ansaldo, since winding is not yet ready) • 3 out-of-service following the string-2 incident: need work to investigate and put in conformity. • 1 suspected short circuit (in the tunnel, after late review of test in SM18), MB1055. • Of the 40 MBs actually available • one needed more examination:MB2252 incident ROCLA; re-tested and used of OSQAR but waiting Performance Assent • 3 were waiting Performance Assent. Chamonix 09 Highlights

31. Magnets in D-zone • 15 SSS (MQ) • 1 not removed (Q19) • 14 removed • 8 cold mass revamped (old CM, partial de-cryostating for cleaning and careful inspection of supports and other components). • 6 new CMs • In this breakdown there is consideration about timing (SSS cryostating tales long time; variants problems). • 42 Dipoles (MBs) • 3 not removed (A209,B20,C20) • 39 removed • 9 Re-used (old CM, no de-cryostating – except one?). • 30 new CMs. • New cold masses are much faster to prepare than rescuing doubtful dipoles. Chamonix 09 Highlights

32. Magnet repair schedule • Magnets of sector 34 back in tunnel Mid-April. ‘Success oriented’ schedule. • Magnet rescue, repair and construction facility in former West Hall (B180), expected to be ready ~ summer 2009. • 30 magnets will be rescued and rebuild, timescale ~ Mid-2010. Chamonix 09 Highlights

33. Magnet Training to 7 TeV Presentations by A. Verweij Chamonix 09 Highlights

34. Dipole circuit quenches Nominal current ~11800 A 9310 A corresponds to 5.5 TeV (5 TeV + 10% margin) Chamonix 09 Highlights

35. Magnet distribution / sector Chamonix 09 Highlights

36. Dipole training during HWC Chamonix 09 Highlights

37. Quenches to 7 TeV • The expected number of RB circuit quenches needed to reach 6, 6.5, and 7 TeV is about 10, 80, and 900 respectively. 900 is a rough estimate since it is based on a large extrapolation of the S56 training curve. • Assuming training in all 8 sectors in parallel, with 3 quenches per day would then require about 60 days to reach 7 TeV, and about the same number of heater firings as the entire SM-18 test campaign. • The issue: every quench also presents a very small but non-zero risk for the magnet… Some debate among experts. • There will be no training before 2011. Chamonix 09 Highlights

38. Cryogenics Presentations by S. Claudet Chamonix 09 Highlights

39. First beams around LHC All sectors at nominal temperature First cool-down of LHC sectors Cool-down time ~ 4-6 weeks/sector Short in connection cryostats and repairs Open Days Christmas and water maintenance shut-down UX85 Ph1 work Chamonix 09 Highlights

40. Electrical Transformers 19 Sept’08 LHC cryogenics towards beam Target for global (8 sectors) “Cryo OK for Powering” Beams !!! ‘Cryo Maintain’ is a cryo status signal required to power the magnets. Indicates Cryo is ready ! UX85 Ph1 works Chamonix 09 Highlights

41. 19 Sept’08 LHC cryogenics : after beam A bit frustrating !!! So far it is a tricky to have the cryogenics up at 100% for more than a week >> 2009 challenge !! Target for 4 sectors tested with calorimetry Switch EL network Chamonix 09 Highlights

42. He inventory • LHC runs with ~ 120 tons of He. • Losses of 20-30 tons are considered ‘normal’ (by cryo group) Chamonix 09 Highlights

43. Machine Protection Issues Presentations by V. Kain, B. Goddard, B. Holzer Chamonix 09 Highlights

44. Energy Scales 450 GeV ‘156 b’ physics 450-900 kJ Safe Beam Limit - 1012 p 72 kJ Pilot b 360 J Nominal b 8.3 kJ Nominal beam 23.3 MJ Stored Energy (J) 5 TeV Safe Beam Limit - 1.7x1010 p 13.6 kJ 100 1k 10k 100k 1M 10M 100M 1T ‘156 b’ physics 5-10 MJ Pilot b 4 kJ Nominal b 92 kJ Nominal beam 258 MJ Stored Energy (J) 2 MJ ! 100 1k 10k 100k 1M 10M 100M 1T Chamonix 09 Highlights

45. MPS Issues • Already with 156 bunch operation we will exceed Tevatron, HERA & SPS in terms of stored beam energy: such a beam can slice open a magnet and trigger another sector-34 like incident. • Many persons are worried about the complexity of the LHC MPS/interlock system (‘will never work’-like comments from Tevatron and HERA…): but we MUST make it work – or we will never be safe. • We learned a lot from Tevatron, HERA and SPS ‘mistakes’ (i.e. cracks in the MPS) and avoided them from the start… • In Chamonix we finally got green light to perform the MPS tests with beam (low intensity) that are essential to asses the MPS performance (reaction times). • Non-negligible time – not counted in the schedules… Chamonix 09 Highlights

46. Scheduling Presentations by K. Foraz, M. Batz, discussion session. Chamonix 09 Highlights

47. Shutdown 08-09 Sectors 12, 34, 56, 67 warmed up • Intermediate cool-down & QRL warm-up (Stand Alone) • Activities • Arc • LSS • Flushing & ELQA at warm • Cool-down • Powering tests • Cold check-out OP group is trying to schedule injection tests for August – similar to 2008 EN/MEF/LPC – J.Coupard & K.Foraz

48. Today’s cheapest EDF Prices Today’s operation

49. Power consumption Additional cost for running in winter ~ 12 MCHF Chamonix 09 Highlights

50. Schedule options… Chamonix 09 Highlights