Nb3Sn IR Quadrupole Program GianLuca Sabbi Second joint HiLumi LHC and LARP CM19 Meeting Frascati, November 14-16, 2012

Topics/Goals for HiLumi-CM19 Development of 150 mm aperture IR Quadrupole – QXF models Primary program focus, in preparation for construction project Discuss how to address the most urgent technical issues Refine model program: SQXF (1-2 m) and LQXF (3-4 m) Identify and resolve key interfaces with other Work Packages (Re)define and prioritize R&D plan in support of QXF Conductor development, cable and coil fabrication, support structures and assembly, field quality, quench protection, radiation resistance, powering, cooling, alignment… Expect 2-3 years before first QXF tests Several platforms available, the most relevant are LQ, HQ, LHQ Large investments to develop/optimize, ready to harvest results Limited resources: only higher priority items can be preserved

QXF Progress since CM18 Aperture selection was main focus of CM18 – a clear direction emerged Formal decision to adopt 150 mm was announced in early July DOE guidance and program response following the aperture selection: Formulate integrated plan US-CERN Agreed on general approach and key program elements Established CERN and US coordinators Assigned deliverables and developed preliminary schedules Reorganize LARP effort around the QXF development and coordinate with US core programs (GAD) for additional resources Current focus on cable development, conceptual design Significant redirection of LARP resources starting in 2013 Discussions are underway to define GAD contributions

QXF Focus Areas for HiLumi/CM19 Most critical issue: establish the cable design and fabrication process Initial reference parameters were provided already at CM18 Procured strand (CDP & LARP) and fabricated many short sections Complex optimization expected to require several more months Conceptual design: identify critical issues (mechanics, protection etc.) Interfaces with other WPs: WP2 → WP3: requirements dynamic effects, persistent currents Urgent – has direct impact on cable development WP3 → WP2: provide/discuss estimates for field errors WP3 ↔ WP6: powering and protection scheme WP3 ↔ WP10: energy deposition and shielding requirements

QXF Focus Areas (2/2) Organization of winding tests at different Labs to confirm cable choice Also an opportunity to establish process for end part design In parallel, perform design studies for various options, to be prepared to finalize the cross-section shortly after the cable (~March 2013) Next on critical path will be the design of coil parts and tooling Approach: identical parts, tooling, processes for all QXF models Requires coordination of design and integrated procurements For longer-term planning: Refine schedule and links between short and long models Role of SQXF/LQXF models vs. pre-series prototype (MQXF) Construction plans for Q1/Q3 (US) vs. Q2a/b (CERN): compare assumptions for infrastructure, effort/schedule, cost

R&D Status/Plans – Conductor Two main conductor designs have been used in LARP: RRP 54/61 for SQ, LR, and 1st generation TQ/LQ/HQ/HQM models RRP 108/127 for TQS03, LQS03, HQ/HQM, LHQ and QXF startup Several new developments are underway, but time window is limited A clear, realistic plan needs to be formulated and implemented Better developed (high & well controlled Jc/RRR; long pieces Larger filament size (magnetization effects, flux-jumps) Smaller magnetization effects and flux-jumps Less developed: control of properties, piece length Increase and control Jc, RRR, piece length in RRP 108/127 Demonstrate potential alternatives (PIT, higher stack RRP) Scale-up to larger billets for faster production an lower cost

R&D Status/Plans – LQ Platform 90 mm aperture, 4 m long, 200 T/m target gradient Achieved in LQS01, surpassed by 10% in LQS01b Reproduced best TQ (short) models built with the same conductor (RRP 54/61) Latest LQ model (LQS03) uses RRP 108/127 with a target of 240 T/m (same as TQS03 with 108/127) First test achieved 208 T/m with fast initial training Overall good result, but several open questions: Some results suggest a mechanical limitation Unreliable SG data prevents direct confirmation Low RRR may also be a contributing factor A second assembly/test may help clarify these issues Next in the plan: studies of quench protection limits

R&D Status – HQ Platform 120 mm aperture, 1.5 m long, 3x TQ/LQ forces, energy HQ01 series of tests is close to completion: 184 T/m at 1.9K! Above 90 mm, 240 T/m scaling Fine preload tuning together with full alignment Encouraging data on stress & protection limits Issues with coil design and fabrication process Several HQM (mirror) tests of single coils: Fast feedback on coil performance limits Reaches SSL, but training is slow HQ02 assembly expected in February Incorporates cored cables, coil design and process improvements However, new features are not uniformly implemented in all coils Cable and parts are available for a third series of coils (HQ03) HQ HQM

R&D Plans – HQ Platform HQ01e-3: magnetic measurements and quench protection studies HQ02: test second-generation HQ coils including provisions for coil expansion during reaction provisions for improved electrical integrity cored cables for suppression of eddy current effects HQM: test of special coils Rad-hard epoxies (Matrimid and Cyanate ester) New conductor designs (RRP 169, 217 and PIT wire) HQM mechanical optimization in view of LHQ, QXF mirrors HQ03 model with 4 identical coils of final design and process Realistic field quality & performance reference for HL-LHC Depending on program needs, HQ02-03 coils could also be used to validate new mechanical structures (BNL, longitudinal stacking)

R&D Status/Plans – LHQ Platform After review, LHQ scope was reduced from quadrupole to mirror test Goal: validate in long coils the design features optimized in HQ Cored cables to control eddy current effects 1-pass cable for core compatibility and more efficient process Braided insulation replacing fiberglass sleeve for long unit lengths Decreased azimuthal compaction and increased longitudinal gaps to control conductor strain during reaction Ti-doped conductor for increased strain tolerance Aluminum oxide coatings for coil parts insulation Optimized end parts to increase insulation, avoid sharp points Increased inter-layer insulation layer thickness to 0.5 mm Redesigned protection heaters, to avoid end spacer crossing Evaluation/validation of Rad hard epoxies in long coils

R&D Planning at HiLumi/CM19 The R&D studies outlined in the previous slides are important for QXF and HL-LHC Relatively small effort compared with the investment already made These studies were part of the LARP plan, in fact the LHQ program is significantly reduced from the one presented at the last review All results can be obtained in the next 2-3 years, before (in some cases, much before) they could be produced by the QXF platform However, LARP will not be able to support this R&D while developing the 150 mm models according to the current schedule Discussions are underway to use a combination of LARP and core programs to carry out these studies Goal for HiLumi/CM19 is to discuss possible optimizations, define priorities and potential contributions to use as input for planning

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 Next few years will be critical and much work is still left to do: Develop 150 mm aperture models and prototypes Address remaining R&D challenges: control of dynamic effects, electrical integrity, process documentation, QA, rad- hard epoxies, develop and select production-class conductors Need to integrate LARP effort with CERN, and core magnet development programs in US and EU Laboratories