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BNL - FNAL - LBNL - SLAC
Quadrupole Models TQ and HQ LHC IR Upgrades
Workshop October 3-4, 2005 Gian Luca Sabbi
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LARP Magnet Program Goals
Overall goal Provide options for future
upgrades of the LHC Interaction Regions
FY09 Milestone Demonstrate viability of
Nb3Sn technology for Quad-first option
1. Capability to deliver predictable,
reproducible performance TQ (Technology
Quads) D 90 mm, L 1 m, Gnom gt 200 T/m 2.
Capability to scale-up the magnet length
LQ (Long Quads) D 90 mm, L 4 m, Gnom gt 200
T/m 3. Capability to reach high gradients in
large apertures HQ (High Gradient Quads) D
90 mm, L 1 m, Gnom gt 250 T/m
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Model Magnet Parameters Aperture

• Optimal aperture for the LHC IR upgrade may be
  larger than 90 mm
• Difficult to finalize choice until several more
  years
• A 90 mm aperture was chosen for the quadrupole
  models, because

• A) It is directly applicable to the LHC IR
  upgrade
• IR upgrade scenarios using 90 mm quads have
  been developed
• B) It is sufficient to investigate the critical
  magnet RD issues
• Conductor/cable designs and performance
• Magnetic design peak fields in the coil up to
  15 Tesla
• Mechanical design conductor stress up to
  150-200 MPa
• C) Larger apertures would lead to more costly,
  less effective RD
• Cross-section area increases linearly with
  aperture
• Conductor requirements for 4-m long and high
  gradient models
• Several models for each type are needed, with
  practice spare coils
• Larger aperture also impacts cost for tooling,
  structures, testing etc.

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Model Parameters Gradient, Length
Gradient/coil field

• Quadrupole magnets are generally characterized
  in terms of gradient
• For magnet RD the coil peak field is a better
  performance indicator
• Goal of high gradient models is to demonstrate
  15 Tesla coil field
• Results can help determine the maximum
  performance characteristic
• Quad aperture/gradient will be scaled following
  IR optimization
• Benefits of moderate aperture choice apply to
  high field model RD

Scale-up to long Nb3Sn magnets is a major RD
issue

• fabrication of long lengths of conductor/cable
  with uniform properties
• stress control during coil reaction handling of
  reacted coils
• support structures, magnet assembly

A 4 meter length is considered adequate for
technology proof Magnetic parameters will be the
same for LQ as for TQ
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Technology Quads (TQ)

• Objective contribute to developing the
  technology base for LQ HQ
• evaluate conductor and cable performance
  stability, stress limits
• develop and select coil fabrication procedures
• select the mechanical design concept and support
  structure
• demonstrate predictable and reproducible
  performance
• Implementation two series, same coil design,
  different structures
• TQS models shell-based structure
• TQC models collar-based structure
• Magnet parameters
• 1 m length, 90 mm aperture, 11-13 T coil peak
  field
• Nominal gradient 200 T/m maximum gradient
  215-265 T/m

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Conductor Coil Design

• Conductor
• Strand diameter 0.7 mm
• Cable 27 strands
• 1.0 degrees keystone
• Width 10.05 mm
• Mid-thickness1.26 mm
• Insulation S-2 glass sleeve
• Coil
• double-layer shell
• one (inner layer) wedge/octant

TQ1a/2a coil cross-section
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TQS01 Shell-based Structure

• Concept
• Aluminum shell over yoke and pads
• Assembly based on bladders and keys
• Advantages
• Can deliver very high pre-stress
• Large pre-stress increase at cool-down
• Easy assembly/disassembly/reassembly
• RD issues
• Coil alignment, field quality
• Long vs. segmented shells

TQS01 test expected to take place in
February-March 2006
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TQC01 Collar-based Structure

• Concept
• Support by thick SS collars
• Assembly w/external press
• Advantages
• Proven coil positioning
• Proven length scale-up
• RD issues
• Deliver required pre-stress
• Pre-stress overshoot
• Flexibility for RD

TQS01 test expected to take place in April-May
2006
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High-Gradient Quads (HQ)
Goal achieve 15 T coil field (300 T/m in the
90 mm aperture)
3-layer G260-290 T/m
4-layer G280-310 T/m
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HQ Design Issues
Conductor - strand (optimal design, critical
current at high field) - cable (limits on
maximum width keystone angle) Magnetic -
number of layers (cable design, winding
issues) - use of wedges, conductor grading, end
field optimization Mechanical - collar-based
vs. shell-based structure - structure and coil
alignment - end axial support Integration -
coordination with model magnet, supporting
RD - coordination with IR magnets study -
fabrication, cost and schedule considerations -
target parameters, design features, RD plan
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IR Quad Design Space