1. S. Caspi, LBNL HQ Magnet Program Shlomo Caspi LBNL LARP DOE Review FNAL June 1-2, 2011 BNL Jesse Schmalze Mike Anarella Peter Wanderer Arup Gosh FNAL Rodger Bossert Dariusz Bocian Guram Chlachidze Giorgio Ambrosio Emanuela Barzi Sasha Zlobin LBNL Helene Felice Paolo Ferracin Dan Dietderich Ray Hafalia Dan Cheng John Joseph Juan Lizarazo Maxim Martchevskii Xiaorong Wang GianLuca Sabbi

2. S. Caspi, LBNL Outline The HQ program and Target Magnet Design Test Results Improvements and plans LARP DOE review, FNAL June 1-2, 2011 2

3. S. Caspi, LBNL HQ Program & Targets Program Part of the US LHC Accelerator Research Program (LARP) Develop Nb 3 Sn quadrupole magnet for the LHC luminosity upgradeDevelop Nb 3 Sn quadrupole magnet for the LHC luminosity upgrade. Magnet Goals Extend Nb 3 Sn magnet technology:Extend Nb 3 Sn magnet technology: – TQ, 1 m long, 90 mm bore, 13T (1.9K) -> without field quality – LQ, 4 m long, 90 mm bore, 13T (1.9K) -> without field quality with field quality – HQ, 1 m long, 120 mm bore, 15T (1.9K) -> with field quality HQ program target:HQ program target: –160 (T/m) at 4.4K HQ01d reached 170 T/m –160 (T/m) at 4.4K (HQ01d reached 170 T/m, 11.8T) –175 (T/m) at 1.9K –Establish engineering phase space – training, ramp-rate, memory A collaboration between BNL/FNAL/LBNL (CERN testing) 3 LARP DOE review, FNAL June 1-2, 2011

4. S. Caspi, LBNL A collaboration program Cable design and fabricationLBNL Magnetic design & analysisFNAL, LBNL Mechanical design & analysis LBNL Coil parts design and procurementFNAL Instrumentation & quench protectionLBNL Winding and curing tooling designLBNL, FNAL Reaction and potting tooling designBNL Coil winding and curingLBNL Coil reaction and pottingBNL, LBNL Coil handling and shipping toolingBNL Structures (baseline, revised, mirror) LBNL, BNL, FNAL Assembly (baseline, revised, mirror) LBNL, BNL, FNAL Magnet testLBNL, CERN, FNAL Accelerator IntegrationBNL, LBNL, FNAL

5. S. Caspi, LBNL 5 HQ - Coil LARP DOE review, FNAL June 1-2, 2011

6. S. Caspi, LBNL HQ – Alignment Keys Alignment keys for field quality 6 LARP DOE review, FNAL June 1-2, 2011

7. S. Caspi, LBNL HQ – Aluminum Collars 1.Assemble and align the coils, 2.Displace the yoke to reduce saturation effects 7 LARP DOE review, FNAL June 1-2, 2011

8. S. Caspi, LBNL HQ – Iron Pads Iron pads complete the coil subassembly 8 LARP DOE review, FNAL June 1-2, 2011

9. S. Caspi, LBNL Merging two subassemblies Coil subassembly is placed within the structure subassembly 9 LARP DOE review, FNAL June 1-2, 2011

10. S. Caspi, LBNL Final Assembly and Pre-stress Four “Masters” are used to align and pre-stress the two subassemblies during the key and bladder operation 10 LARP DOE review, FNAL June 1-2, 2011

11. S. Caspi, LBNL LARP – HQ Magnet 11 0.8 mm strand 15 mm wide cable 120 mm bore Short sample: 4.4 K/1.9 K -195/214 T/m Short sample: 4.4 K/1.9 K – 13.7/14.9 T LARP DOE review, FNAL June 1-2, 2011

12. S. Caspi, LBNL Room temperature before loading 12 LARP DOE review, FNAL June 1-2, 2011

13. S. Caspi, LBNL Gap opening between load key and pad master Bladder operation * Large scale factor to simulate displacements 13 LARP DOE review, FNAL June 1-2, 2011

14. S. Caspi, LBNL Shimming of the load key with 600  m stainless steel shims * Large scale factor to simulate displacements Key insertion 14 LARP DOE review, FNAL June 1-2, 2011

15. S. Caspi, LBNL  R of 270  m * Large scale factor to simulate displacements Cool-down 15 LARP DOE review, FNAL June 1-2, 2011

16. S. Caspi, LBNL  R of 78  m * Large scale factor to simulate displacements With Lorentz forces at 219 T/m 16 LARP DOE review, FNAL June 1-2, 2011

17. S. Caspi, LBNL Coils Assembly and Alignment 17 Alignment Keys Collars Coil & heater LARP DOE review, FNAL June 1-2, 2011

18. S. Caspi, LBNL ANSYS 3D Analysis 1.Axial pre-load 2.Azimuthal pre-load 3.Cool-down 4.Excitation 1.Low pre-stress during assembly 2.Cool-down and high pre-stress 3.No stress overshoot 4.Reusable structural components 18 LARP DOE review, FNAL June 1-2, 2011

19. S. Caspi, LBNL HQ - Azimuthal Stress -212 -188 -164 -140 -116 -92 -68 -44 -20 MPa Average cold stress in HQ is 140 MPa but local stress expected to exceeds 200 MPa TQS performed above 90%, 150 MPa average stress and over 200 MPa local stress R=120 mmR=90 mm 19 LARP DOE review, FNAL June 1-2, 2011

20. S. Caspi, LBNL HQ Progress JulySelection of 120 mm quadrupole aperture for Phase 1 2008JulySelection of 120 mm quadrupole aperture for Phase 1 Sept.Cable and coil cross-section geometry finalized Apr.HQ01a test coils 1,2,3,4 2010Apr.HQ01a test coils 1,2,3,4 71%-79%,141-157T/m (unusual ramp rate performance) June HQ01b test coils 1,4,5,6 77%,153 T/m (electrical breakdown) JulyLARP DOE Review: … Need to understand certain performance limitation Oct. HQ01c test coils 1,5,7,8 70%-138T/m (unusual ramp rate performance) 2011 Apr.HQ01d test coils 5,7,8,9 86%, 170 T/m (mechanical limit) MayHQM01 mirror test coils 12 MayHQM01 mirror test coils 12 Status:13 coils completed, 4 HQ tests completed, 1 mirror test 20 LARP DOE review, FNAL June 1-2, 2011

21. S. Caspi, LBNL Test Results LARP DOE review, FNAL June 1-2, 2011 21

22. S. Caspi, LBNL HQ01 Training (4.4K) 22 HQ01a 13683A (157T/m, 79% of ss) coils 1,2,3,4 coils 1,2,3,4 HQ01b 13308A (153T/m, 77% of ss) coils 1,4,5,6 coils 1,4,5,6 HQ01c 11953A (138T/m, 70% of ss) coils 1,5,7,8 coils 1,5,7,8 HQ01d 14983A (170T/m, 86% of ss) coils 5,7,8,9 coils 5,7,8,9 LARP DOE review, FNAL June 1-2, 2011

23. S. Caspi, LBNL Coil azimuthal stress during excitation LARP DOE review, FNAL June 1-2, 2011 23 Unloading during excitation (linear with I^2) Additional pre-stress is required

24. S. Caspi, LBNL Lesson learned – TQ pre-stress 150 MPa is not a hard limit for magnet performance. Impact of pre-stress on current plateau LARP DOE review, FNAL June 1-2, 2011 24

25. S. Caspi, LBNL HQ01d magnetic measurement nNormal (b n )Skew (a n ) 30.21-3.17 4-0.63-4.16 50.930.33 65.61-0.17 70.96-0.57 80.440.02 9-0.120.30 101.884.23 Harmonics at 120 T/m (average up-down ramp) Measuring coil radius and length= 21.55 mm, 100 mm long Measuring coil radius and length = 21.55 mm, 100 mm long Data shown at a reference radius = 40 mm, 2/3 bore LARP DOE review, FNAL June 1-2, 2011 25

26. S. Caspi, LBNL LARP DOE review, FNAL June 1-2, 2011 26 Protection heater studies delay time Stainless steel protection heater strip on the outer layer Increasing the insulation thickness between protection heaters (PH) and coils.= longer delay times optimize energy distribution to coils

27. S. Caspi, LBNL Performance Assessment Observed limitations and deficiencies 27 LARP DOE review, FNAL June 1-2, 2011

28. S. Caspi, LBNL Ramp-rate dependence Inverted ramp rate behavior “holding quenches” LARP DOE review, FNAL June 1-2, 2011 28

29. S. Caspi, LBNL Observed limitations and deficiencies: HQ01b (coil 6 layer to layer and end-shoe) HQ01a LARP DOE review, FNAL June 1-2, 2011 HQ01a (coil 2 to protection heaters) Insulation fragmentation after reaction Broken strands during reaction 29

30. S. Caspi, LBNL 30 Impulse Tests on HQ Coils Voltage Impulse test on a damaged coil showing arcing activity 10  s Test on coil showing no arcing activity LARP DOE review, FNAL June 1-2, 2011

31. S. Caspi, LBNL Excessive Coil Compaction Jesse Schmalzle HQ13 Coil springing out of reaction tooling LQ 16 Coil remains in reaction tooling HQ coils tend to spring out from their reaction tooling Even with one turn less HQ coil #13 still tends to spring out LARP DOE review, FNAL June 1-2, 2011 31

32. S. Caspi, LBNL Performance Assessment Observed limitations: Voltage breakdown (HQ01a,b tests) Insulation damage (HQ01a,b tests) Broken strands (coil #10) Spring-back after reaction Unusual ramp rate performance (HQ01c tests) Low plateau magnet performance (HQ01c test) A common cause – Coils under excessive compaction during curing and reaction 32 LARP DOE review, FNAL June 1-2, 2011

33. S. Caspi, LBNL Reducing Coil Compaction LARP DOE review, FNAL June 1-2, 2011 33

34. S. Caspi, LBNL Near term Reducing coil compaction - Near term Coil #12 - last turn below mid-plane, larger cavity (mirror test) 34 LARP DOE review, FNAL June 1-2, 2011 Coil #13 – removed one turn, same cavity (next mirror test)

35. S. Caspi, LBNL Mirror Test Study individual coil items: Cable, Core, Epoxy, Insulation New structure, similar to TQ

36. S. Caspi, LBNL HQM01 Coil #12 - ramp rate dependence Loss pre-stress with cool-down non-linear with current square First HQ mirror test Issues remain: pre-stress, ramp rates 4.6 K LARP DOE review, FNAL June 1-2, 2011 36 Cable with core Core not removed in splice Inverted rate below 150 A/s Significant improvement in ramp rate dependence

37. S. Caspi, LBNL Next step Reducing coil compaction - Next step 37 LARP DOE review, FNAL June 1-2, 2011 Keep existing cross-section and HQ tooling Reduce strand diameter from 0.800 mm to 0.778 mm Reduce cable size (will be discuss by Arup) Allow expansion during reaction 4.5% thickness, 2.3% width Despite the performance of coil 12 (perhaps not directly related to compaction) we still believe that the over compaction of the coil is important and needs to be solved Make room for coil expansion during reaction Additional R&D items: radiation resistance epoxy, cyanide- ester insulation, core cable, RRP 217, alternative structure

38. S. Caspi, LBNL Next Coil - HQ14 Parameters HQ14 Previous HQ Cable parameters Width14.8 (2.3 % reduction) mm (2.3 % reduction)15.15 Mid-thickness 1.375 (4.5% reduction) mm (4.5% reduction)1.44 35 strands – 0.778 mm 35 strands - 0.800 mm Insulation 100microns Type sleeve (S) or tape (E) sleeve Island gap size 4343 mm/m for 1 pass mm/m for 2 pass 2.7 closed 1.0 closed Interlayer insulation 20mils10 design LARP DOE review, FNAL June 1-2, 2011 38

39. S. Caspi, LBNL Next Magnet Test – HQ01e LARP DOE review, FNAL June 1-2, 2011 39 Increase magnet pre-stress by 10-20 MPa Improve pre-stress coils uniformity using different shim sizes Investigate current plateau and impact on field uniformity

40. S. Caspi, LBNL HQ Summary A 120 mm bore, Nb 3 Sn quadrupole is underway construction and testing - established engineering phase space4 tests (HQ01a/b/c/d) - established engineering phase space 160 (T/m) target exceeded, 170 (T/m),160 (T/m) target exceeded, reached 170 (T/m), 86% SS (4.4K) Coil compaction cause of performance limitation: –Excessive strain puts coils at risk but some can perform Future plans:Future plans: –Pre-load and field quality studies using “selected” coils –Mirror test using special coils –Quench protection tests using both HQ and the mirror –Reduce strand diameter and cable size –New series of coils with less compaction –Test optimized models at 1.9K (CERN) 40 LARP DOE review, FNAL June 1-2, 2011