D. Schoerling FCC Week Washington L. Bottura, J. van Nugteren, M. Karppinen 26/03/2015 1

FCC-hh magnets B / G (T) / (T/m) B peak (T) Bore (mm) Length (units x m) MB x 14.3 MQ450 (>350) x 6 MQX (<150) MQY MBX x2 x 12 MBR x3 x 10 2 See Talk of L.Bottura and E. Todesco for magnet specifications Inter-aperture distance ≈ 250 mm Yoke diameter ≤ 700 mm

3 R. Gupta, PAC, pp. 3239, 1999 Cos-  Block Common-coil Canted-Cos-  S. Caspi, FCC kick-off meeting, SC Magnet Development Toward 16 T Nb3Sn Dipoles L. Brouwer, IEEE Trans. Appl. Supercond., Vol. 25, No. 3, 2015 Eurcard-del-D7-3-1-fullfinal, Dipole model test with one supeconducting coil, results analyzed, Deliverable: D7.3.1 A.F. Lietzke, IEEE Trans. Appl. Supercond., Vol. 13, No.2, 2003 Design options MB

J C pays a lot at 4.2 K, less at 1.9 K. Margin is (very) expensive (at 4.2 K). HL-LHC FCC FCC ? 4 Strand improvement & margin

Magnet costs. MQE. Power consumption. Overall investment costs to be compared. Cooling with supercritical helium (temperatures between 1.9 K and 4.2 K possible). 5 LHC installed, best values at installed capacity LHC data courtesy of Philippe Lebrun I = 12kA -> Area constant, Sc/Non-Sc 1:1 I cable is calculated at 80% on the load line for other T Choice of temperature Carnot

Grading is essential for obtaining cost-efficient magnet designs (a factor ~3 of cost saving compared to a non- graded coil). Nb-Ti can be used to generate background field. No large cost dependence on the amount of used Nb-Ti. 6 See also talk of Jeroen van Nugteren for more scaling relations! Grading

7 Parameters of cables MB

Number of apertures(-)2 Aperture(mm)50 Inter-aperture spacing(mm)250 Operating current(kA)16.4 Operating temperature(K)1.9 Nominal field(T)16 b 2/3 Aperture b 2/3 Aperture Peak field(T)16.3 Margin along the load line(%)~20 Stored magnetic energy per unit length(MJ/m)3.2 Fx (per ½ coil)kN/m7600 Fy (per ½ coil)kN/m-3800 Inductance (magnet)(mH/m)22.8 Yoke ID(mm)- Yoke OD(mm)700 Weight per unit length(kg/m)2500 Area of SC(mm 2 )6650 Area of cable low-Jc Nb 3 Sn(mm 2 )7180 Area of cable high-Jc Nb 3 Sn(mm 2 )10900 Area of cable Nb-Ti(mm 2 )4000 Turns Low-J Nb 3 Sn per pole-19 Turns High J Nb 3 Sn per pole-41 Turns Nb-Ti per pole-15 MB – 1.9 K 8 1 m diameter “cryostat” envelope Mechanical concept: Bladder-Key

9 1 m diameter “cryostat” envelope Mechanical concept: Collared coils Number of apertures(-)2 Aperture(mm)50 Inter-aperture spacing(mm)250 Operating current(kA)17.2 Operating temperature(K)1.9 Nominal field(T)16 b 2/3 Aperture b 2/3 Aperture Peak field(T)16.4 Margin along the load line(%)~20 Stored magnetic energy per unit length(MJ/m)3.6 Fx (per ½ coil)kN/m8960 Fy (per ½ coil)kN/m-4310 Inductance (magnet)(mH/m)23.7 Yoke ID(mm)- Yoke OD(mm)700 Weight per unit length(kg/m)2500 Area of SC(mm 2 )7390 Area of cable low-Jc Nb 3 Sn(mm 2 )9070 Area of cable high-Jc Nb 3 Sn(mm 2 )9840 Area of cable Nb-Ti(mm 2 )4520 Turns Low-J Nb 3 Sn per pole-24 Turns High J Nb 3 Sn per pole-37 Turns Nb-Ti per pole-17 MB – cos- 1.9 K

10 Nb 3 Sn: IL Nb 3 Sn: OL1 Nb-Ti: OL2 Nb 3 Sn: IL Nb 3 Sn: OL1 MB

11 Discussion MB Design(-)Block Cos-  Operating current(kA) Operating temperature(K)1.9 Nominal field(T)16 b 2/3 Aperture Fx (per ½ coil)kN/m Fy (per ½ coil)kN/m Inductance (magnet)(mH/m)

Magnets at 1.9 K at ~20% or 4.2 K at ~12% margin have reasonable cross-sections with f=1.5. Improvement of strand and/or reduction of margin required (main cost driver). Grading (~3 cables) is needed. Block and cos-  design need similar amount of conductor. Mechanical structure to be studied: Cos-  : Collars, Bladder-key concept for bi-aperture design. Block: Collars, Bladder-key concept for bi-aperture design. Magnet protection (J Cu limited). Optimization of field quality. Sagitta (~2.5 mm). 12 Discussion MB

13 Parameters of cables MQ

14 Number of apertures(-)2 Aperture(mm)50 Inter-aperture spacing(mm)250 Operating current(kA)19.5 Operating temperature(K)1.9 Nominal gradient(T/m)376 b 2/3 Aperture b 2/3 Aperture Peak field(T)10.5 Margin along the load line(%)20 Stored magnetic energy/unit length(MJ/m)0.55 Fx (per ½ coil)kN/m1240 Fy (per ½ coil)kN/m-1681 Inductance (magnet)(mH/m)2.8 Yoke ID(mm)169 Yoke OD(mm)660 Weight per unit length(kg/m)2500 Area of SC(mm 2 )1400 Area of cable Nb 3 Sn(mm 2 )2850 Area of cable Nb-Ti(mm 2 )0 Turns per pole, inner layer-9 Turns per pole, outer layer-13 Design by M. Karppinen MQ – 1.9 K

15 Number of apertures(-)2 Aperture(mm)50 Inter-aperture spacing(mm)250 Operating current(kA)26.1 Operating temperature(K)1.9 Nominal gradient(T/m)380 b 2/3 Aperture b 2/3 Aperture Peak field(T)10.5 Margin along the load line(%)20 Stored magnetic energy/unit length(MJ/m)0.59 Fx (per ½ coil)kN/m1496 Fy (per ½ coil)kN/m-2095 Inductance (magnet)(mH/m)1.2 Yoke ID(mm)184 Yoke OD(mm)620 Weight per unit length(kg/m)2000 Area of SC(mm 2 )1420 Area of cable Nb 3 Sn(mm 2 )3200 Area of cable Nb-Ti(mm 2 )0 Turns per pole, inner layer-7 Turns per pole, outer layer-10 Design by M. Karppinen MQ – 1.9 K

16 Parameters of cables MQX

17 Number of apertures(-)1 Aperture(mm)100 Inter-aperture spacing(mm)- Operating current(kA)26.2 Operating temperature(K)1.9 Nominal gradient(T/m)225 b 30 mm b 30 mm Peak field(T)12.4 Margin along the load line(%)20 Stored magnetic energy/unit length(MJ/m) 1.1 Fx (per ½ coil)kN/m- Fy (per ½ coil)kN/m- Inductance (magnet)(mH/m)4.3 Yoke ID(mm)288 Yoke OD(mm)700 Weight per unit length(kg/m)2100 Area of SC(mm 2 )1820 Area of cable(mm 2 )4100 Turns per pole, inner layer-14 Turns per pole, outer layer-17 Design based on HL-LHC IR-Quad QXF, see M. Karppinen, Indico & & CERN- ACC for mechanical concept MQX 1.9 K

Quadrupole design with grading may allow to increase the gradient (380 T/m to required 450 T/m) and provide some cost saving. MQXF coil design (150 mm aperture) could serve as proof of principle for collared FCC Nb 3 Sn quadrupoles. Mechanical concept as for MQXF demonstrator but smaller aperture. 18 Discussion MQ & MQX

19 MQXF – Demonstrator (IRQ) bution/21/material/slides/3.pdf

20 MQXF – Demonstrator (IRQ) Number of apertures(-)1 Aperture(mm)150 Inter-aperture spacing(mm)- Operating current(kA)18.8 Operating temperature(K)1.9 Nominal gradient(T/m)140 b 50 mm b 50 mm Peak field(T)12.1 Margin along the load line(%)18 Stored magnetic energy/unit length(MJ/m)1.32 Fx (per ½ coil)kN/m- Fy (per ½ coil)kN/m- Inductance (magnet)(mH/m)8.2 Yoke ID(mm)330 Yoke OD(mm)600 Weight per unit length(kg/m)2000 Area of SC(mm 2 )1815 Area of cable Nb 3 Sn(mm 2 )4540 Area of cable Nb-Ti(mm 2 )0 Turns per pole, inner layer-22 Turns per pole, outer layer-28

MQXF - Mechanical concept Bladder-key (single aperture). System chosen for HL-LHC. Small amount of magnets to be produced. Collared coils with punched SS collars. Industrial experience of collared coils. Infrastructure available. G. Ambrosio and P. Ferracin, QXF magnet design and plans, HiLumi-LHC/LARP Conductor and Cable Internal Review October 2013 CERN M. Karppinen, CERN-ACC

MQXF - Collared coils Magnet in pressCold-mass after cool down Filler wedge Loading Plate St. steel t = 2 mm Insulation t = 0.2 mm Stress relieve notch St.steel keys 10x12 mm Press 22 M. Karppinen, CERN-ACC

Discussion MQXF Demonstrator Coil stress between 0 and 150 MPa at all times. Stress and strain management of all components seems straight forward. Detailed mechanical optimization about to be started. Assembly possible with existing tools and easily available components. -> Demonstrator easily possible! Direct comparison between collar and bladder-key concept. Scale-up straight forward, once long coils are available. 23

24 Conclusions Dipoles: 16 T dipoles seem feasible with reasonable cross-sections. Improvement of strand and/or reduction of margin required. Grading (~3 cables) is needed. Block and cos-  design need similar amount of conductor. Mechanical structure to be studied. Magnet protection (J Cu limited). Quadrupoles: New mechanical concept proposed. Detailed analysis about to be started. Demonstrator easily possible based on MQXF. Quadrupole gradient to be increased by using grading. R&D programme required – See talk of L. Bottura/Appendix

Focus on the “piece de resistance” (improperly translated as “main course”) : LTS 16 T MB and conductor R&D 16 T dipole concepts 16 T dipole design Hi-Jc, Lo-cost conductor ( HiLo ) Demonstrator: HD, DMC Technology: SC, SMC/RMC 25 See talk of L. Bottura A plan for discussion

Objectives Develop basic concepts and materials for the magnet technology required to achieve the LTS FCC-hh performance targets TaskDescription Margin and trainingDevelop techniques and materials to reduce training and operating margin, covering conductor design, epoxy types, additives, bonding characteristics, glass charge homogeneity, impregnation technology. Understand and improve magnet training memory Quench detection & magnet protection Develop improved/alternatives for quench detection and magnet protection, including interlayer quench heaters, inner layer heaters, pulsed current protection schemes, calculate thermally induced stress to decide on the allowable hot-spot temperature Heat transferCharacterize and develop methods to increase heat removal from impregnated windings Radiation and protection Develop designs and materials that decrease the exposure to radiation loads, increase protection, reduce activation Design toolsProgress on integrated design tools (EM design, mechanics, magnet protection) 26 Magnet technology R&D – 1/2

TaskDescription Cable splicesDevelop technology for splices among cables (Nb 3 Sn to Nb 3 Sn and Nb 3 Sn to NbTi) Coil gradingDevelop robust technology for the grading of Nb 3 Sn magnet winding (coil assembly methods, including interlayer splices) Cost studiesAnalyze the cost of magnet manufacturing, examine low cost designs, and manufacturing procedure for cost reduction Coil windingDevelop winding techniques with additives, winding tooling, automated winding Coil insulationDevelop improved insulation schemes (fibers, resins) compatible with HT cycles, higher voltage withstand, radiation hardness Heat treatmentUnderstand and allow for dimensional changes during heat treatment, and related dimensional tolerances Magnet structureDevelop existing concepts (collars, bladder-and-key) and novel concepts for the magnet support 27 Magnet technology R&D – 2/2 Objectives Develop existing and novel techniques and materials as necessary for a cost-optimized LTS FCC-hh ng