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Cryomagnets , Interconnections, Superconducting Circuits:

Cryomagnets , Interconnections, Superconducting Circuits:. What to do in 2012/13 if you are not consolidating splices ? . Cryomagnets , Interconnections, Superconducting Circuits:. What to do in 2012/13 if you are not consolidating splices ? .

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Cryomagnets , Interconnections, Superconducting Circuits:

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  1. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Chamonix 2011 LHC Performance Workshop

  2. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • Context : The impact of these “special” interventions • In-situ work or cryomagnet replacement ? • Reasons for an intervention: • Vacuum related issues • Cryogenics related issues • Electr(omechan)ical integrity • Beam optics • DS Collimators • Miscellaneous • How many cryomagnets exchange? Spares? • The special interventions team and the work location • Conclusions Chamonix 2011 LHC Performance Workshop

  3. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Context : The impact of these “special” interventions • Limited space • Shared human resources • Limited time (Minimise the impact on the shutdown duration) • Interventions on the same circuits Chamonix 2011 LHC Performance Workshop

  4. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  In-situ work or cryomagnet replacement? (1/2) Sequence touches 4 half cells (216 m) • Many operations with > 6 different teams:IC, ELQA, VSC, Survey, BLM, QA,… and an heavily interleaved sequence • Actions on circuits sometimes not sectorised over 3 km (beam lines, cryo lines) • Also technical and schedule interferences Chamonix 2011 LHC Performance Workshop

  5. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  In-situ work or cryomagnet replacement? (2/2) All cryomagnets are not equivalent: By increasing difficulty: - Standard cryodipole - Standard SSS without jumper - Standard SSS with jumper - DS(6kA) cryodipole - DS(6kA) SSS without jumper - DS(6kA) SSS with jumper - Cryoassemblies connected to a DFBA - DSs @P6 are specific (No Q7, Jumper on Q10 instead of Q9 …) - LSS ? (Variable-No rule) For a “standard” cryodipole: Duration: 6 weeks from opening of IC to reclosure if non-stop work considering one extended day (12 hours) in one shift Workload: About 600 man hours per standard cryodipole replacement Welders, mechanics, electromechanics, ELQA, QA, leak tester Less if consecutive magnets Chamonix 2011 LHC Performance Workshop

  6. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Vacuum related issues (1/3) Leaks • Subsector is localized but not the exact leak origin • Time is required before opening & during the shutdown for leak detection/localisation • Present status : about 20 leaks / 11 are important / 1 is critical (A27L4) • Usually, repairable in-situ • New leaks could appear before the next long shutdown or be created by the warm-up • Typical sequence: • Leak detection / confirmation on each subsector during warm-up • Opening of the interconnections • Leak localisation (Requires circuit pressurisation: Safety & Coordination) • Leak repair • Repair validation • Conclusion: • Work on all leaks to improve the situation • Only one cryomagnet could have potentially to be exchanged (A27L4) Chamonix 2011 LHC Performance Workshop

  7. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Vacuum related issues (2/3) A non-conformity of the RF fingers during their fabrication can lead to a failure of the component during the warm -up • PIMs : • Buckled during warm-up : based on last warm-up after SSS displacement : ≈ 18 (RF ball test) • Heavily damaged : ≤ 10 • Preventive replacements : • + Arc extremities18/32 in baseline+ Not in the baseline: QQBI and QBQI close to a SSS with vacuum barrier (356 or 862) to decrease the risk of bucking in case of local warm-up Conclusion: About 45 PIMs are considered to be replaced Low risk of failure in case of local warm-up that could require venting to replace the failed PIM and a subsequent scrubbing run (≈ a week) Chamonix 2011 LHC Performance Workshop

  8. Cryomagnets, Interconnections, Superconducting Circuits: QBQI.10L5, NCR 831037, nested bellows V2 What to do in 2012/13 if you are not consolidating splices ?  Vacuum related issues (3/3) Nested bellows: About 55 small damages identified / 2 are heavier Inspection will be carried out (VSC) to confirm that they do not need to be changed. Useful only in case of cryogenics operation error. Can survive a few accidental cases  No replacement planned • Beam screens: • One with leaking cooling capillary (S81): 2 were bypassed for symmetry No need for intervention • Wrong type of beam screen (saw-teeth profile): 12 MBs/2 SSSs mainly in 34This could be an issue for cryogenics and electron cloud build-up • VSC follows that with ABP & CRG • No replacement planned so far but impact in terms of resources described later ; Would mean 14cryomagnets more to remove and surface work Chamonix 2011 LHC Performance Workshop

  9. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Cryogenics related issues (1/3) Consolidation of SAM Helium level gauges Level gauge reading was not stable Existing capillary replaced by a larger metal hose Details in ECR: LHC-LQN-EC-0001 It is planned to consolidate the 2 remaining ones (Q6R2, Q6L8) during the long shutdown Repair of leaking Y-lines It is planned to consolidate the 2 known cases (S78:17-19R7 & S81:19-22R8) during the long shutdown Chamonix 2011 LHC Performance Workshop

  10. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Cryogenics related issues (2/3) Installation of Pressure Relief Devices To be installed on cryodipoles (DN200) during next shutdown in 23, 45 (part), 78 & 81: ≈ 600 units and on 2 SAM (DN160) Chamonix 2011 LHC Performance Workshop

  11. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Cryogenics related issues (3/3) Triplets braid 3 weeks of work per triplet (not full time) To be done in second part of the shutdown (ALARA) Priority 1 are included in the baseline (HL exp) Priority 2 will be done if time is available Cryo-Instrumentation Access will be given to allow cryo-team to intervene Chamonix 2011 LHC Performance Workshop

  12. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • Electr(omenchan)ical integrity (1/4) Details in ECR: LHC-LE-EC-0003 Consolidation of the Connection Cryostats • Risk of short to ground on main BB due to supports displacement • Addition of extra insulation to go up to ultimate energy • The proposed plan is : • Measure and if necessary consolidate the CC 11L8 • Consolidate the CC in 11L3 (If DSColl. not installed) & 11L1 • Measure / inspect all the CCs to check no displacement Chamonix 2011 LHC Performance Workshop

  13. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • Electr(omenchan)ical integrity (2/4) Circuit issues (Open, high R) • Investigation will be carried out • Some tests could be required before warm-up • Repair procedure to be defined • New issues could occur • Special splices: • 600 A: in 78 : sampled inspections • 6kA:(see presentation by F Bertinelli, LHC Splices Task Force)Opening for inspection of line N boxes not fully documented (sampling) and/or 8L and/or possible outliers found during splice mapping for inspection and possible consolidation • 13 kA (DFBA): access and one specific case Chamonix 2011 LHC Performance Workshop

  14. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • Electr(omenchan)ical integrity (3/4) Cryomagnets issues: High internal splice resistance From Zinur Charifoulline Dipoles Quads No change of the splice resistance even after this extensive fatigue test in SM18 To be analysed in the LHC machine in details Why should a magnet with a high internal splice resistance be replaced ? To be disconnected for DS Coll installation • Not for cryogenics reason (OK for extra heat load) • Not for electrical reason • For mechanical reason Scheme from C Scheuerlein # to exchange (proposal) + 8 dipoles (4A&4B) in S12&23) & 1 SSS (in S34) + Test programme  Reduction by 50 % of inner resistance Note small value ! Chamonix 2011 LHC Performance Workshop

  15. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • Electr(omenchan)ical integrity (4/4) Cryomagnets issues Has also a high inner splice resistance # to exchange (proposal) + 5 dipoles Chamonix 2011 LHC Performance Workshop

  16. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Beam optics • Wrong SSS types (S34):[LHC-LQA-EC-0004 M Modena] • 2 circuits are degraded (one is missing) (Q23,27,28,32 R3): [2 with jumpers] • MQS: Q23,27 • MO: Q28,32 • Q5L8 : Warm corrector installed (78) • To be replaced by a new Q5 L8 Priority to be given to RQS circuit (ABP input) # to exchange : Proposed baseline : 2 (Q23R3, Q27R3) Chamonix 2011 LHC Performance Workshop

  17. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  DS Collimators (See previous presentation by V Parma) • 32 cryo-assemblies to be: • Disconnected • Brought to surface • Reworked • Reinterconnected Involves surface work # to “exchange” : Baseline : 32 Chamonix 2011 LHC Performance Workshop

  18. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Miscellaneous • BPM cables checks and repairs • RP samples : See ECR LHC-LI-EC-0001 for details • Recover and measure some of them ; • New ones to be installed ? • New issues appearing before long shutdownDetected during operation (Higher L, E, time…) • Non-conformities generated during the long shutdown Chamonix 2011 LHC Performance Workshop

  19. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  • How many cryomagnets to exchange? Spares? • For MBs, spares should be available. • If reversed BS to be changed, this will have to be done in SMI2 • For SSSs, 3 should be available before the start of the shutdown (2012)A balance between time saved and procurement of new cryostat components needs to be done • Work at the surface will be required to rework the extremities of removed cryomagnets Chamonix 2011 LHC Performance Workshop

  20. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  The special interventions team *Based on 12 months between opening of the first IC and closure of the last one • Surface work (SMI2, 180) to be considered in addition. • Change of cryomagnets with reversed BS would strongly impact [+ 5.5 FTE] Ratio of experienced staff  Chamonix 2011 LHC Performance Workshop

  21. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  The work location 5 4 6 SSS Cryo-dipole High inner splice Highest leak Electrical integrity issue Reversed beam screen(s) 3 7 DS Coll. Beam optics SAM (He, DN160) Y-lines repair CC Consolidation / Inspection DN 200 installation Triplet braid Circuit and splices issues Spread all around : work on leaks, PIMs, 2 8 1 Chamonix 2011 LHC Performance Workshop

  22. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Conclusions • The list of interventions on superconducting magnets and circuits (other than main splices consolidation) has been presented. • Work is foreseen all along the LHC • A team to carry out these interventions in the allocated time has been presented; the ratio of experienced staff (<1/3) seems low • The assumed baseline does not include the exchange of cryomagnets with a reversed beam screen; adding this would have a major impact (resources, time?) • Extra preparatory work is required to gain knowledge on inner splices with high resistance • A value of 30% for new issues & NC seems more realistic Chamonix 2011 LHC Performance Workshop

  23. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Thank you for your attention And to many persons for their infos, slides, inputs, … ? Chamonix 2011 LHC Performance Workshop

  24. Cryomagnets, Interconnections, Superconducting Circuits: What to do in 2012/13 if you are not consolidating splices ?  Spare slides Splices test programme • Actions to get data to make an educated decision: • Replace “only” magnets that will not withstand the LHC lifetime with margin • Detailed modeling of all the dipole inner splices and of the EM forces • Determine correlation between electrical resistance and mechanical strength (model and test on dedicated samples) and see if it is a relevant criterion[Will also define the correlation between cryolab and FRESCA resistance measurements] • Perform extra tests on cold masses (removed from tunnel ?) and/or on representative samples (No of cycles  LHC lifetime equivalent) to validate acceptable resistance level (Approach used for the 6 kA pray-hand splices) Chamonix 2011 LHC Performance Workshop

  25. High internal splices resistances (1/5) LHC machine and spare status The cryodipole specification is < 7 nOhm for dipoles All were measured precisely several times (nQPS) From Zinur Charifoulline Dipoles: 40 (13A,27B) > 7.5 nOhm 18 (7A, 11B) > 10 nOhm (≈ 5 ) 3 (1A,2B) > 20 nOhm (> 10 ) Quads: 4(5) are > 10 nOhm 1 [Q7R3] is > 20 nOhm Spare dipole CM: Max: 21A, 23B (44 in total) ≈ 8.1 nOhm Tested : 12A, 11B (23 tested) ≈ 9.6 nOhm Chamonix 2011 LHC Performance Workshop

  26. High internal splices resistances (2/5) Experience so far 3 cases : 2 from the machine and 1 from the spares stock 2334:(S12): R ≈ 100 nOhmInterpole splice D1 2303:(S67): R ≈ 50 nOhmInterpole splice D2 2420:(Spare): R ≈ 25 nOhmInteraperture splice Pictures from H Prin (MSC-LMF) Ref: LHC Project Note 430 : Dipole Magnet Splice Resistance from SM18 data Almost no soldering in splices Chamonix 2011 LHC Performance Workshop

  27. High internal splices resistances (3/5) Degradation : Experience so far • 2303:(S67): R ≈ 50 nOhmInterpole splice D2 • Extensively tested in SM18 in 2009: • 1000 cycles from 50A to 9 kA (5 TeV eq.) @ 50A/s • 10 hours @ 9kA • 6 provoked quenches @ 9 kA • Thermal cycle to RT • Training up to 11850A • 500 cycles from 5kA to 11.85 kA (Nom) • 10 hours @ 11.85kA • 5 provoked quenches @ 11.85 kA • Training up to 12.85 kA (Ultimate) in 2 natural quenches Test report EDMS No1008959 : Splice Resistance measurements in SM18 : 2303 (TE-MSC-TF) No change of the splice resistance even after this extensive fatigue test in SM18 To be analysed in the LHC machine in details Chamonix 2011 LHC Performance Workshop

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