Preliminary Design of Nb 3 Sn Quadrupoles for FCC-hh M. Karppinen CERN TE-MSC

Outline Specs used for this initial study IR Quadrupole Strong IR Quad based on QXF IR Quad meeting the spec Main Quadrupole Next steps

“Specs” from L. Bottura (Aug -14) B / G (T) / (T/m) B peak (T) dB/dt (mT/s) Bore (mm) Length (units x m) FCC MB x 14.3 MQ x 6.6 QX Optics ? D x2 x 12 D x3 x 10 Booster in the FCC MB x 14.3 injector in the LHC MB x 14.3 injector in the SPS MB x 4.7 M. Karppinen CERN TE-MSC

Strong IR Quad based on QXF FCC will require large number of challenging magnets based on Nb 3 Sn-technology that will require industrial production CERN have long experience with industrially built accelerator magnets (design, part procurement, production methods & tools, acceptance tests) 11 T Dipole is the first Nb 3 Sn magnet that has been designed from the beginning to be compatible with accelerator quality requirements. The design concept and certain new features can be applied on Nb 3 Sn quadrupole HL-LHC IR-Quad QXF has been extensively optimized making it a good reference for comparing with the alternative design concept Demonstrator magnet based on QXF coil design could be made using primarily existing tooling and with modest investment on certain magnet components (collars, yoke lams, shells, end plates) Possible plan-B for HL-LHC in case the present base-line design fails meeting the performance criteria M. Karppinen CERN TE-MSC

HF Quadrupole Design Concept Industrial accelerator quality design: Collared coils, fine-blanked/precision punched SS collars Iron yoke, fine-blanked/precision punched SS collars Welded SS outer shell Well known assembly methods and tooling: Dipole-type collars, assembly in (existing) dipole collaring press H/V split yoke, assembly in (existing) dipole yoking press 11 T Dipole experience: Pole loading principle adapted to quadrupole coils Coil pre-compression applied in controlled and easily tunable fashion during collaring Welded outer shell with acceptable and achievable stress levels Very rigid and static mechanical structure with closed yoke gap M. Karppinen CERN TE-MSC

Collared QXF Magnet Conceptual design study based on QXF coils ø150 mm coil aperture kA (150 kA) poles are not part of the coil (not potted together) additional outer layer wedge & SS loading plate Dipole type collars (IR 115 mm, OR 160 mm) Horizontally split laminated yoke, OD 600 mm Welded stainless steel outer shell (15 mm) M. Karppinen CERN TE-MSC

18.8 kA & 150 T/m M. Karppinen CERN TE-MSC

Modified QXF Coil Filler wedge Loading Plate St. steel t = 2 mm Insulation t = 0.2 mm M. Karppinen CERN TE-MSC

Collared Coil 12° St.steel keys 10x12 mm R115 R160 Ti-alloy pole wedge Stress relieve notch Shim M. Karppinen CERN TE-MSC

Radial deformation after collaring => Horizontal split yoke 0.2 mm 0.05 mm M. Karppinen CERN TE-MSC

Yoke & Shell Al-gap controller R160.4 R300 Stainless steel Shell t = 15 mm Weld shrinkage 0.84 mm Taper mm Ø81.75 M. Karppinen CERN TE-MSC

Azimuthal Coil Stress Collaring Press After Collaring After Yoke Assembly 293 K After Cooldown 1.9 K 17.4 kA 140 T/m 18.8 kA 150 T/m MPa M. Karppinen CERN TE-MSC

Collar Stress (Von Mises) M. Karppinen CERN TE-MSC After collaring After yoke assembly At 293 K After cooldown at 1.9 K At 1.9 K, 150 T/m

Yoke & Gap-controller After Yoke Assembly 293 K After Cooldown 1.9 K 18.8 kA 150 T/m Gap-controller defines the yoke gap during yoke assembly Yoke gap is closed after cooldown and remains firmly closed up to 150 T/m Azim. Shell Stress after Yoke assembly MPa M. Karppinen CERN TE-MSC

Summary of QXF based IR Quad Coil stress between 0 and 150 MPa at all times. Coil stress distribution can be customized to counter-balance the magnetic forces. Very rigid collars provide the pre-stress in controllable way with only small elliptic deformation Tapered yoke mid-plane gap and gap-controller provide static and very rigid structure from CM assembly down to 1.9 K and 150 T/m 15 mm SS shell stress at acceptable levels at all stages using achievable welding shrinkage Rigid structure maintains very well the quadrupole symmetry. Assembly possible with existing tools and easily available components. Scale-up straight forward, once long coils available. M. Karppinen CERN TE-MSC

IR Quad Demonstrator magnet Use QXF coils: First end spacer on IL/OL with slot, wind & cure with existing tooling After binder curing add filler wedge and reaction pole React with existing QXF reaction tool Add loading plates and impregnation pole Vacuum impregnate with existing QXF tooling Introduce pole wedges, ground insulation, and collaring shoe Collar assembly in existing collaring press with new press tool Yoke and outer shell assembly in 180 yoking press with new end plates Protection heaters can be identical to QXF Instrumentation can be identical to QXF 2 years can be considered realistic time-scale including part procurement and manufacturing time with appropriate human resources M. Karppinen CERN TE-MSC

QX “Specs” B / G (T) / (T/m) B peak (T) dB/dt (mT/s) Bore (mm) Length (units x m) FCC MB x 14.3 MQ x 6.6 QX Optics ? D x2 x 12 D x3 x 10 Booster in the FCC MB x 14.3 injector in the LHC MB x 14.3 injector in the SPS MB x 4.7 M. Karppinen CERN TE-MSC

QX Cable OST RRP-108/127 M. Karppinen CERN TE-MSC

QX Coil X-section Aperture Ø90 mm 36 turns (IL 16, OL 20) No grading I-L insulation 0.7 mm Mid-plane insul. 0.2 mm FQ r30mm (200 T/m): b6 = 0.8 units b10 = 0.18 unit L diff = 4.26 mH/m E mag = 401 kJ/m Field errors with iron saturation at 200 T/m M. Karppinen CERN TE-MSC

QX K G(13.4 kA) = 200 T/m Bp(13.4 kA) = 10 T wp(13.4 kA) = 77 % wp(13.4 kA, 4.3K) = 83 % T marg = 5.4 K Bc = 13 T M. Karppinen CERN TE-MSC

QX Magnet X-Section Yoke OD 275 mm ID mm M. Karppinen CERN TE-MSC

FCC IR Quadrupole Parameters M. Karppinen CERN TE-MSC

QX Mechanical Structure Coil features Removable Ti-alloy poles (not glued in) Additional outer layer wedge & stainless steel loading plate. Wedges made of ODS alloy. S2-glass-Mica cable insulation Dipole type collars (IR 75.4 mm, OR mm) Horizontally split laminated yoke, OD 550 mm Al-gap controller Welded stainless steel outer shell (15 mm) M. Karppinen CERN TE-MSC

QX Collared Coil Ti-alloy pole wedge Coil assembly 12° Stress relieve notch Shim R74.4 R103.5 M. Karppinen CERN TE-MSC

QX Yoke & Shell Al-gap controller R103.9 R275 Stainless steel Shell t = 15 mm Weld shrinkage 0.84 mm Taper mm Ø81.75 M. Karppinen CERN TE-MSC

QX Azimuthal Coil Stress MPa Collaring Press After Collaring After Yoke Assembly 293 K After Cooldown 1.9 K 13.4 kA 200 T/m 15 kA 223 T/m M. Karppinen CERN TE-MSC

QX Summary Magnetic design based on 13.7 mm Nb3Sn cable meets the present specification with comfortable margin The mechanical design, further development of the 11 T Dipole pole-loading concept, provides very stable support structure for the coils The design is adapted for industrial production based on existing production methods and tools M. Karppinen CERN TE-MSC

MQ “Specs” B / G (T) / (T/m) B peak (T) dB/dt (mT/s) Bore (mm) Length (units x m) FCC MB x 14.3 MQ x 6.6 QX Optics ? D x2 x 12 D x3 x 10 Booster in the FCC MB x 14.3 injector in the LHC MB x 14.3 injector in the SPS MB x 4.7 M. Karppinen CERN TE-MSC

MQ Cable OST RRP-108/127 M. Karppinen CERN TE-MSC

MQ Coil X-section Aperture Ø40 mm 18 turns (IL 7, OL 11) No grading I-L insulation 0.7 mm FQ r10mm (383 T/m): B6 = units B10 = 0.00 unit B14 = 0.07 units L diff = 1.96 mH/m E mag = 251 kJ/m Field errors with iron saturation at 383 T/m M. Karppinen CERN TE-MSC

MQ K G(16 kA) = 383 T/m Bp(16 kA) = 8.6 T wp(16 kA) = 75 % T marg = 5.9 K Bc = 11.6 T M. Karppinen CERN TE-MSC

MQ Magnet X-Section Yoke OD mm ID 550 mm Beam separation 250 mm Magnetically very similar down to 180 mm separation Mechanical concept based on dipole collars M. Karppinen CERN TE-MSC

FCC Main Quadrupole Parameters M. Karppinen CERN TE-MSC

Next steps.. Engineering design of IR Quad Demonstrator based on QXF coils (DAI raised) Demonstrator magnet construction & test MQ mechanical design Design iteration based on “more serious” specs Final design Model magnet program Prototype magnets Series production M. Karppinen CERN TE-MSC