d. schoerling fcc week washington l. bottura, j. van nugteren, m. karppinen 26/03/2015 1

1

LTS high-field magnet design options for FCC-hh

D. Schoerling

FCC Week Washington

L. Bottura, J. van Nugteren, M. Karppinen

26/03/2015

2

FCC-hh magnets

B / G(T) / (T/m)

Bpeak

(T)Bore(mm)

Length(units x m)

MB 16 16.4 50 4500 x 14.3

MQ 450 (>350) 12.5 50 800 x 6

MQX 225 12.4 100 (<150)

MQY 300 13 70

MBX 12 12.5 60 4x2 x 12

MBR 10 10.5 60 4x3 x 10

See Talk of L.Bottura and E. Todesco for magnet specifications

Inter-aperture distance ≈ 250 mmYoke 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

4

• JC pays a lot at 4.2 K, less at 1.9 K.

• Margin is (very) expensive (at 4.2 K).

HL-

LHC HL-

LHCF

CC

FC

C ?

0.8 0.9 1 1.1 1.2 1.3 1.4 1.50.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

4.2 K

1.9 K

JC improvement factor (-)

FCC

Uni

ts o

f Mag

net C

ost (

-)

-0.1 0.1 0.30.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

4.2 K1.9 K

Margin (-)

FCC

Uni

ts o

f Mag

net C

ost (

-)

Strand improvement & margin

5

• 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).

1.7 2.2 2.7 3.2 3.7 4.2 4.70

0.51

1.52

2.53

Temperature in K

FCC

Units

of M

agne

t cos

ts

(-)

1.7 2.2 2.7 3.2 3.7 4.2 4.70

200

400

600

800

1000

Temperature in K

COP

in W

/W

LHC installed, best values at installed capacity

LHC data courtesy of Philippe Lebrun

1.7 2.2 2.7 3.2 3.7 4.2 4.70

2

4

6

8

10

Temperature in K

MQ

E (m

J)

Icable @1.9K = 12kA -> Area constant, Sc/Non-Sc 1:1Icable is calculated at 80% on the load line for other T

Choice of temperature

Carnot

6

• 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.

See also talk of Jeroen van Nugteren for more scaling relations!

Grading

3 3.5 4 4.5 5 5.5 60.94

0.96

0.98

1

1.02

1.04

1.06

1.08

1.1

1.12

Field contribution of Nb-Ti Layer (T)

FCC

Units

of M

agne

t Cos

ts (-

)

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IL OL 1 OL 2

Strand, reacted

SC Material Nb3Sn Nb3Sn Nb-Ti

Strand diameter (mm) 1.33 0.92 0.92Filament diameter (mm)Cu/Non-Cu - 1.2 3.4 3.4

Jc (1.9 K, 15 T) (A/mm2) 3000 3000 -

Jc (1.9 K, 10 T) (A/mm2) - - 1350

Jcu @ Inom (A/mm2) ~650 ~650 ~650

Degradation % 10 10 10RRR >150 >150 >150

CableNumber of strands - 34 50 50Mid-Thickness (mm) 2.38 1.65 1.65Thin Edge (only cos-theta) (mm) 2.4 1.7 1.7Thick Edge (only cos-theta) (mm) 2.2 1.5 1.5Width (mm) 24 24 24Keystone angle (only cos-theta) deg 0.4 0.4 0.4Core thickness (mm) - - -Core material St. Steel Cu TBD Cu TBD

InsulationInsulation thickness (mm) 0.15 0.15 0.15Insulation material S2-Mica S2-Mica Polyimide

Prelim. Study: Indico 375934

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) 16b2 @ 2/3 Aperture 10-4 40.5b3 @ 2/3 Aperture 10-4 2.8

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/m 7600

Fy (per ½ coil) kN/m -3800Inductance (magnet) (mH/m) 22.8

Yoke ID (mm) -

Yoke OD (mm) 700

Weight per unit length (kg/m) 2500

Area of SC (mm2) 6650Area of cable low-Jc Nb3Sn (mm2) 7180Area of cable high-Jc Nb3Sn (mm2) 10900

Area of cable Nb-Ti (mm2) 4000Turns Low-J Nb3Sn per pole - 19Turns High J Nb3Sn per pole - 41

Turns Nb-Ti per pole - 15

MB – block @ 1.9 K

8

1 m diameter “cryostat” envelopeMechanical concept: Bladder-Key

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1 m diameter “cryostat” envelopeMechanical concept: Collared coils


Aperture (mm) 50




Nominal field (T) 16b2 @ 2/3 Aperture 10-4 48.7b3 @ 2/3 Aperture 10-4 8.1

Peak field (T) 16.4

Margin along the load line (%) ~20

Stored magnetic energy per unit length (MJ/m) 3.6


Fy (per ½ coil) kN/m -4310

Inductance (magnet) (mH/m) 23.7

Yoke ID (mm) -

Yoke OD (mm) 700


Area of SC (mm2) 7390Area of cable low-Jc Nb3Sn (mm2) 9070Area of cable high-Jc Nb3Sn (mm2) 9840

Area of cable Nb-Ti (mm2) 4520Turns Low-J Nb3Sn per pole - 24Turns High J Nb3Sn per pole - 37

Turns Nb-Ti per pole - 17

MB – cos- @ 1.9 K

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Nb3Sn: IL

Nb3Sn: OL1

Nb-Ti: OL2

Nb-Ti: OL2

Nb3Sn: IL

Nb3Sn: OL1

MB

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Discussion MB

Design (-) Block Cos-Operating current (kA) 16.4 17.2Operating temperature (K) 1.9 1.9Nominal field (T) 16 16b2 @ 2/3 Aperture 10-4 40.5 48.7Fx (per ½ coil) kN/m 7600 8960Fy (per ½ coil) kN/m -3800 -4310Inductance (magnet) (mH/m) 22.8 23.7

• 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 (JCu limited).

• Optimization of field quality.• Sagitta (~2.5 mm).

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Discussion MB

13

MQ V3 MQ V4Strand, reactedStrand diameter (mm) 0.711 1.015Filament diameter (mm) 46 46Cu/Non-Cu - 1.028 1.25

Jc (4.2 K, 12 T) (A/mm2) 3450 3450Degradation % 5 5

CableNumber of strands - 42 30Trasp. Angle (deg) 14.5 145Mid-Thickness (mm) 1.298 1.833Thin Edge (mm) 1.241 1.772Thick Edge (mm) 1.354 1.895Width (mm) 15.887 16.423Inner edge compaction - 0.874 0.873Outer edge compatcion - 0.953 0.933Width compaction - 1.034 1.049Keystone angle deg 0.41 0.43Core thickness (mm) 25 25Core material St. Steel St. Steel

InsulationInsulation thickness (mm) 0.14 0.14Insulation material S2-Mica S2-Mica

Parameters of cables MQ

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Aperture (mm) 50




Nominal gradient (T/m) 376

b6 @ 2/3 Aperture 10-4 0.1

b10 @ 2/3 Aperture 10-4 3.9

Peak field (T) 10.5

Margin along the load line (%) 20

Stored magnetic energy/unit length (MJ/m) 0.55




Yoke ID (mm) 169

Yoke OD (mm) 660


Area of SC (mm2) 1400

Area of cable Nb3Sn (mm2) 2850

Area of cable Nb-Ti (mm2) 0

Turns per pole, inner layer - 9

Turns per pole, outer layer - 13Design by M. Karppinen

MQ – V3 @ 1.9 K

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Aperture (mm) 50





b6 @ 2/3 Aperture 10-4 0.0

b10 @ 2/3 Aperture 10-4 2.6

Peak field (T) 10.5






Yoke ID (mm) 184

Yoke OD (mm) 620






Turns per pole, outer layer - 10Design by M. Karppinen

MQ – V4 @ 1.9 K

MQX V2Strand, reactedStrand diameter (mm) 1.015Filament diameter (mm) 43Cu/Non-Cu - 1.25Jc (4.2 K, 12 T) (A/mm2) 3450Degradation % 5RRR - >80

CableNumber of strands - 42Trasp. Angle (deg) 14.5Mid-Thickness (mm) 1.859Thin Edge (mm) 1.778Thick Edge (mm) 1.939Width (mm) 22.696Inner edge compaction - 0.863Outer edge compatcion - 0.955Width compaction - 1.034Keystone angle deg 0.41Core thickness (mm) 25Core material St. Steel

InsulationInsulation thickness (mm) 0.14Insulation material S2-Mica

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Parameters of cables MQX

17


Aperture (mm) 100

Inter-aperture spacing (mm) -




b6 @ 30 mm 10-4 0.2

b10 @ 30 mm 10-4 -0.2

Peak field (T) 12.4



Fx (per ½ coil) kN/m -

Fy (per ½ coil) kN/m -


Yoke ID (mm) 288

Yoke OD (mm) 700



Area of cable (mm2) 4100


Turns per pole, outer layer - 17

Design based on HL-LHC IR-Quad QXF, see M. Karppinen, Indico 373031 & 375934 & CERN-ACC-2014-0244 for mechanical concept

MQX V2 @ 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 Nb3Sn quadrupoles.

• Mechanical concept as for MQXF demonstrator but smaller aperture.

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Discussion MQ & MQX

IRQStrandStrand diameter (mm) 0.85Filament diameter (mm)Cu/Non-Cu - 1.2Jc (1.9 K, 15 T) (A/mm2) 2000Degradation % 5RRR - >150

CableNumber of strands - 40Trasp. Angle (deg) -Mid-Thickness (mm) 1.525Thin Edge (mm) 1.438Thick Edge (mm) 1.612Width (mm) 18.15Inner edge compaction - -Outer edge compatcion - -Width compaction - -Keystone angle deg 0.55Core thickness (mm) 25Core material St. Steel

InsulationInsulation thickness (mm) 0.15Insulation material S2

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MQXF – Demonstrator (IRQ)

http://indico.cern.ch/event/275710/contribution/21/material/slides/3.pdf




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MQXF – Demonstrator (IRQ)Number of apertures (-) 1

Aperture (mm) 150

Inter-aperture spacing (mm) -




b6 @ 50 mm 10-4 0.32

b10 @ 50 mm 10-4 -0.40

Peak field (T) 12.1



Fx (per ½ coil) kN/m -

Fy (per ½ coil) kN/m -


Yoke ID (mm) 330

Yoke OD (mm) 600






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 16-17 October 2013CERN

M. Karppinen, CERN-ACC-2014-0244

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MQXF - Collared coilsMagnet in press Cold-mass after cool down

Filler wedge

Loading PlateSt. steel t = 2 mm

Insulationt = 0.2 mm

Stress relieve notch

St.steel keys10x12 mm

Press

22

M. Karppinen, CERN-ACC-2014-0244

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.

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ConclusionsDipoles:• 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 (JCu 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

25See talk of L. Bottura

A plan for discussion

26

Objectives• Develop basic concepts and materials for the magnet

technology required to achieve the LTS FCC-hh performance targets

Task Description

Margin and training Develop 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 transfer Characterize 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 tools Progress on integrated design tools (EM design, mechanics, magnet protection)

Magnet technology R&D – 1/2

27

Task Description

Cable splices Develop technology for splices among cables (Nb3Sn to Nb3Sn and Nb3Sn to NbTi)

Coil grading Develop robust technology for the grading of Nb3Sn magnet winding (coil assembly methods, including interlayer splices)

Cost studies Analyze the cost of magnet manufacturing, examine low cost designs, and manufacturing procedure for cost reduction

Coil winding Develop winding techniques with additives, winding tooling, automated winding

Coil insulation Develop improved insulation schemes (fibers, resins) compatible with HT cycles, higher voltage withstand, radiation hardness

Heat treatment Understand and allow for dimensional changes during heat treatment, and related dimensional tolerances

Magnet structure

Develop existing concepts (collars, bladder-and-key) and novel concepts for the magnet support

Magnet technology R&D – 2/2Objectives

• Develop existing and novel techniques and materials as necessary for a cost-optimized LTS FCC-hh ng

d. schoerling fcc week washington l. bottura, j. van nugteren, m. karppinen 26/03/2015 1

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