CERN March 11-12, 2002 Superconducting Magnet Program

1S. Gourlay

Lawrence Berkeley National Laboratory

IR Quad R&D Program

LHC IR Upgrade

Stephen A. Gourlay

CERN March 11-12, 2002 Superconducting Magnet Program

2S. Gourlay

LHC IR Quad Program

Goals and Deliverables

(Keeping in mind that there is very little money early in the program)

• Provide a quad design that meets requirements for an LHC IR upgrade– Determine requirements and identify issues

• Develop a technology base for future applications– Emphasize “Research” over “Development”

• Establish a true collaboration that is a model for the future– Leverage from existing programs

• What can participants provide?

• Train the next generation of magnet scientists– Not only developing new technology, but building resources as well

CERN March 11-12, 2002 Superconducting Magnet Program

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LHC IR Quad Program

Design Issues

• Field quality– Conductor placement– Magnetization

• Fabrication– Insulation thickness– Reaction dynamics (long coils)– Rad-hard epoxy

• Operational– Quench protection

• Push Limits• New Ideas

– Heat load• Energy extraction• Optimal operating temperature

Program Components

• Conductor and Cable Development

• Design– Magnetic– Mechanical

• Models– Drawings– Parts– Assembly

• Technology Development– Challenge existing biases

• Jcu

• RRR

CERN March 11-12, 2002 Superconducting Magnet Program

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Design Choices

• Cos(2)– Relatively complex (but familiar)

• Coupled forces• Assembly

– Efficient use of superconductor for large bore magnets

• Racetrack and Block– Relatively simple

• Force geometry• 2-D ends (Racetrack)• 3-D ends (Block)• Rectangular cable

– No degradation– No keystoning “issues”

CERN March 11-12, 2002 Superconducting Magnet Program

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Geom. harm. (r0 = 22 mm)(10-4 units)

b6 b10 b14

0.2 -0.8 0.04

Parameter Unit Inner OuterGss T/m 260Bpk T 12.7 10.8Iss kA 7.7 7.9L mH/m 24.4A(oct) mm2 624Riron mm 90

Four -layer Cos(2

Param. Unit Inner OuterStr. Diam. mm 0.8 0.65Nstrands 18 23Cab. Width mm 7.71 7.71Mid-thick mm 1.43 1.15Keystone deg 1.63 0.89Insulation mm 0.1 0.1Nt

(oct) 37 36Cu/Sc 1.0 1.5Jcu

ss kA/mm2 1.7 1.7

(Jc:2.0/4.2 - No degradation)

CERN March 11-12, 2002 Superconducting Magnet Program

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Cos(2)

• Two-Layer (a la FNAL)

• Four-Layer– Advantages

• Narrow cable – easier to wind, lower degradation• Fully-keystoned cross section – radial alignment• Possible to eliminate wedges – simpler end design• No inter-layer joint for grading• Better magnetic efficiency – mid-plane gap?• Low operating current• Higher gradient – potential for more

– Disadvantages• Tooling for inner and outer layers• Higher inductance – quench protection

CERN March 11-12, 2002 Superconducting Magnet Program

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Cos(2)

• Four-Layer options– Add a spacer if necessary– Add mid-plane gap and decrease bore– Increase strand and cable width – reduce number of turns and decrease

inductance

• Two-Layer options– Large keystone angle - Reduce Cabling degradation– More efficient cross section

CERN March 11-12, 2002 Superconducting Magnet Program

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Block-type Coils

Some attractive features . . .

• Potentially better control over conductor placement– Nb3Sn coils not as precise as NbTi?

• Rectangular conductor– No degradation, higher stability

• Separation of high field and high stress points– So far, no observation of stress degradation up to almost 15 Tesla in

dipoles

• Simplification of support structures and assembly techniques

• Some designs can be oriented to maximize “effective” aperture

CERN March 11-12, 2002 Superconducting Magnet Program

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Block-type Coils

“Nested” Racetrack

CERN BlockDesign

Racetrack Design

CERN March 11-12, 2002 Superconducting Magnet Program

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Conductor and Cable Development

• Conductor– RRR control and optimization– Reaction studies

• Optimization• Pre-anneal

• Cable– Cores

• Keystoned core for large keystone angles and low degradation• AC loss• Stabilizer

– Mixed-strand• Lower cost, tunability

– Compaction studies

CERN March 11-12, 2002 Superconducting Magnet Program

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LBNL Program Proposal

2003

• Conceptual Design– Work on optimization of coil designs – Evaluate the mechanical structure and coil support

 

• Fabrication and Test– Mechanical structure tests.– Using existing two-layer Nb3Sn coils, assemble and test a four-coil quad

configuration as a preliminary evaluation of the assembly, support scheme and training behavior of rectangular geometries.

• Program Supported Studies

CERN March 11-12, 2002 Superconducting Magnet Program

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LBNL Program Proposal

2004 – 2006

• Continue a program that evaluates “flat-coil” options– (Rate of 2 models per year)

2007 – 2008

• Construct Cos(2) design

• Compare with other options 

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Moving Forward

• Who are the participants?

– BNL, FNAL, LBNL

and

– CERN– CEA/Saclay– U. Twente– KEK– INFN

• What can they provide from existing programs?

• In order to make progress early we need to combine effort and use resources from base programs.

• Calls for a new model

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Task Division

Task Lab A Lab B Lab CDesign A

Conductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Design BConductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Design CConductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Technology Studies

Institution

The “SSC” Way

CERN March 11-12, 2002 Superconducting Magnet Program

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Task Division

Task Lab A Lab B Lab CDesign A

Conductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Design BConductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Design CConductor and CableMagnetic DesignMechanical DesignAnalysisDrawingsParts FabAssemblyTest

Technology Studies

Institution

Cross-Integration

Division based on . . .

Resources

Program Contributions

ARP Support

Etc.