ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 1 Nb 3 Sn IR Quadrupoles for HL-LHC GianLuca Sabbi for the LARP – HiLumi LHC Collaboration 2012 Applied Superconductivity Conference

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 2 M. Anerella, J. Cozzolino, J. Escallier, A.K. Ghosh, J. Muratore, S. Peggs, J. Schmalzle, P. Wanderer H. Bajas, M. Bajko, L. Bottura, G. DeRijk, O. Dunkel, P. Ferracin, J. Feuvrier, L. Fiscarelli, C. Giloux, J. Perez, L. Rossi, S. Russenschuck, E. Todesco G. Ambrosio, N. Andreev, E. Barzi, R. Bossert, J. DiMarco, G. Chlachidze, F. Nobrega, I. Novitski, V. Kashikhin, J. Kerby, M. Lamm, P. Limon, D. Orris, E. Prebys, M. Tartaglia, D. Turrioni, G. Velev, M. Whitson, R. Yamada, M. Yu, A. Zlobin S. Caspi, D.W. Cheng, D.R. Dietderich, H. Felice, A. Godeke, S. Gourlay A.R. Hafalia, R. Hannaford, J.M. Joseph, A.F. Lietzke, J. Lizarazo, M. Marchevsky, G. Sabbi, A. Salehi; T. Salmi, R. Scanlan, X. Wang Contributions

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 3 1.Program motivation and goals 2.Overview of LARP magnet R&D 3.Main achievements to date 4.Outstanding technical issues 5.Prototype design and development plans Presentation Outline Related presentations at ASC 2012: G. Ambrosio et al., “Test results and analysis of Long Nb 3 Sn Quadrupole Series by LARP” H. Bajas et al., “Cold Test Results of the LARP HQ01e Nb 3 Sn quadrupole magnet at 1.9 K” D. Cheng et al., “Evaluation of insulating coatings for wind-and-react coil fabrication” G. Chlachidze et al., “Test of optimized LARP Nb 3 Sn quadrupole coil using magnetic mirror structure” A. Ghosh “Perspective on Nb 3 Sn Conductor for the LHC Upgrade Magnets” A. Godeke et al., “Review of Conductor Performance for the LARP High-Gradient Quadrupole Magnets” E. Todesco et al., “Design studies of NbTi and Nb 3 Sn Low-β Quadrupoles for the High Luminosity LHC” X. Wang et al., “A system for high-field accelerator magnet field quality measurements”

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 4 High Luminosity LHC Physics goals: Improve measurements of new phenomena seen at the LHC Detect/search low rate phenomena inaccessible at nominal LHC Increase mass range for discovery Required accelerator upgrades include new IR magnets: Directly increase luminosity through stronger focusing  decrease  * Provide design options for overall system optimization/integration  collimation, optics, vacuum, cryogenics Be compatible with high luminosity operation  Radiation lifetime, thermal margins Figure of merit is integrated luminosity, with a target of 3000 fb -1

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 5 LARP Magnet Program Goal: Develop Nb 3 Sn quadrupoles for the LHC luminosity upgrade Potential to operate at higher field and larger temperature margin R&D phases: : technology development: conductor, coil, structure : length scale-up from 1 to 4 meters : incorporation of accelerator quality features Program achievements to date: TQ models (90 mm aperture, 1 m length) reached 240 T/m gradient LQ models (90 mm aperture, 4 m length) reached 220 T/m gradient HQ models (120 mm aperture, 1 m length) reached 184 T/m gradient Current activities: Completion of LQ program to extend TQ results to long models Optimization of HQ, fabrication of LHQ coils and test in mirror Design and planning of the MQXF IR Quadrupole development

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 6 Overview of LARP Magnets SQ SM TQS LR LQS HQ TQC

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 7 Sub-scale Quadrupoles (SQ) Four “SM” racetrack coils 130 mm bore, length 30 cm Achieved 97% of SSL at 4.5K & 1.9K -Validated conductor for TQ01 models -First shell-based quadrupole structure -Verification/optimization of FEA models -Quench propagation/protection studies C C

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 8 Long Racetracks (LR) SG1SG2SG3SG4SG5SG6 Scale up of “SM” coil and structure: 30 cm to 4 m Coil R&D: first successful length scale-up Structure R&D: friction effects, magnet assembly Achieved 11.5 T, 96% of short sample limit LRS01b: segmented shell LRS01a: single shell P. Ferracin, J. Muratore et al., IEEE Trans. Appl. Supercond. Vol: 18 (2), 2008, pp

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 9 Technology Quadrupoles (TQ) Double-layer, shell-type coil 90 mm aperture, 1 m length Two support structures: - TQS (shell based) - TQC (collar based) Target gradient 200 T/m TQCTQS Three coil series using different wire design MJR 54/61; RRP 54/61; RRP 108/127 More than 30 coils fabricated Distributed coil production line 15 magnet tests in different configurations Two models assembled and tested at CERN

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 10 TQ Highlights Quench performance Maximum gradient 240 T/m 20% above target No retraining Stress limits TQS03a: 120 MPa at pole, 93% SSL TQS03b: 160 MPa at pole, 91% SSL TQS03c: 200 MPa at pole, 88% SSL Peak stresses are considerably higher Considerably widens design window Cycling test 1000 cycles No change in mechanical parameters No change in quench levels

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 11 Long Quadrupole (LQ) S1 (2) D1 (1) S2 (4) S3 (2) S4 (2) D2 (4) D3 (1) TQ length scale-up from 1 m to 4 m Three series of coils All models reached 200 T/m target Recent results and next steps in: G. Ambrosio et al. 4LA-01 (Thursday AM)

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 12 High-Field Quadrupole (HQ) R&D goals: Explore “new territory” in energy and force levels (~3xTQ) Incorporate field quality and full alignment Main parameters: 120 mm aperture, 15 T peak field at 220 T/m (1.9K) Coil stresses approaching 200 MPa (if pre-loaded for SSL)

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 13 R&D issues – Strain during Coil Reaction Results from first HQ models indicated conductor damage in several coils Traced to excessive strain during the coil reaction phase:  No/insufficient gaps in pole segments to limit longitudinal strain  Design/tooling did not include space for azimuthal cable expansion G. Chlachidze et al., 4LA-03 (Thursday AM) HQ02: restored pole gaps and reduced cable size with smaller strand diameter First coil successfully tested in mirror structure: All process improvements incorporated in HQ03 and the Long HQ Coils Coil spring-back from tooling “Inverted” ramp-rate dependence in HQ01a-c

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 14 Large number of insulation failures in coils, coil to parts and coil to heaters Catastrophic failure in HQ01b test due to inter-layer short through end shoe Remediation steps: Redesigned end parts to improve fit, eliminate high pressure areas Application of insulating coatings to coil parts: Improved winding procedures and QA Redesigned quench heaters to minimize crossings above metallic parts Increased insulation between coil layers and between coil and heaters Enhanced electrical QA during coil and magnet fabrication (impulse testing) R&D issues – Electrical Integrity D. Cheng et al., 4MA-08 Thursday AM

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 15 In previous phases of the program, conductor has been adequate to meet the key R&D goals of the model magnets: RRP 54/61 for SQ, LR, and 1 st generation TQ/LQ/HQ/HQM models  Enabled the 2009 milestone of >200 T/m in TQ and LQ RRP 108/127 for TQS03, LQS03, HQ/HQM, and LHQ  Very good results in TQS03, but lower performance in HQ/HQM and LQ  Limitations observed in current density, stability (RRR), piece length Conductor improvements are required for a successful construction project Several developments are underway, but time window is limited  Increase and control J c, RRR, piece length in RRP 108/127  Develop/demonstrate possible alternatives (PIT, higher stack RRP)  Scale-up to larger billets for faster production an lower cost R&D Issues – Conductor and Cable A. Ghosh, paper 2SLE-06 (this session) A. Godeke et al., 4JA-07 (Thursday AM) See presentations by:

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 16 HQ Highlights – Field Quality Discussion of magnetic measurement system by X. Wang et al., 4JE-04 (Thursday PM) Geometric harmonics show good coil uniformity and structure alignment Persistent current effects are large but within limits set by design study Large dynamic effects indicate need to better control inter-strand resistance  Cored cables incorporated in second generation coils Eddy current harmonics for different ramp rates 12 kA, R.ref = mm Block positioning error ~29.6 µm. Analysis of geometric accuracy from random errors R c fit 0.2–3.6 µΩ (LHC target: ~20 µΩ)

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 17 HQ Highlights – Quench Performance Latest results from CERN test of HQ01e at 1.9K: H. Bajas, 4LA-02 (Thursday AM) Achieved 184 T/m at 1.9K (85% of SSL) – well above performance target  However, high rate of coil failures (excessive strain and insulation weakness) Flux jump effects appear less severe at 1.9K (5-10 times smaller amplitude) Quench protection studies: energy extraction delay, then removal of IL heaters

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 18 IR Quadrupole Design Specification - An aperture increase to 150 mm is expected to result in best overall performance - Requires another significant step in energy & force levels with respect to 120 mm Higher Field Larger Aperture (same/lower gradient) Thicker absorbers More Operating Margin (at same gradient / aperture) Longer Lifetime Lower radiation and heat loads Better Field Quality Stronger focusing Higher Gradient (same/lower aperture) Shorter magnets Higher T margin Better IR layout Stable operation Easier cooling More Design Margin (same gradient / aperture) Lower risk Faster development Less cost & time for small production Max. luminosity

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 19 Next Phase: IR Quadrupole Prototype Preliminary layout of HL-LHC final focus using 150 mm bore 140 T/m quadrupoles: Prototype design status: Increased cable size to facilitate coil stress management and quench protection  Cable R&D underway targeting 18.5 mm width, 1.50 mm mid-thickness, 0.65 deg. keystone angle (D. Dietderich)  Strand diameter from mm (HQ) to 0.85 mm to limit aspect ratio Electrical integrity: increase of cable insulation thickness from 0.1 to 0.15 mm Preliminary cross-sections were developed for evaluation Latest developments presented in: E. Todesco et al., 4LA-05 (Thursday AM) 6.77 m2 x 3.99 m6.77 m2 x 3.99 m R. De Maria et al, HiLumi meeting, 7/26/12

ASC 2012Nb 3 Sn IR Quadrupoles for HL-LHC – G. Sabbi 20 Summary A large knowledge base is available after 7 years of fully integrated effort involving three US Labs and CERN  Steady progress in understanding and addressing R&D issues that were perceived as potential show stoppers: conductor performance, mechanical support, degradation due to stress and cycling, length scale-up, coil/structure alignment, field quality, quench protection Remaining challenges include: control of dynamic effects, electrical integrity, process documentation and QA, incorporation of rad-hard epoxies, development and selection of production-class conductors Next few years will be critical and much work is still left to do  Integrating LARP effort with CERN, US core programs, EuCARD HL-LHC IR Quads are a key step for future high-field applications Acknowledgement: