Subscale quadrupole (SQ) series

1
Subscale quadrupole (SQ) series

• Paolo Ferracin
• LARP DoE Review
• FNAL
• June 12-14, 2006

2
Outline

• Motivations and goals
• Magnet design
• SQ02 SQ02b
• Overview
• Design features and axial load
• Test results
• Conclusions and next steps

3
Motivations and goals (SQ01)

• Test of support structure
• Racetrack coil design (LBNL SM Program)
• Assembly with keys and bladders
• Aluminum shell
• Realistic Lorentz forces
• Early feed-back for TQS magnets
• Assembly procedure
• Component alignment
• Stress uniformity
• Goals achieved with SQ01
• Design and fabrication Dec. 03 July 04
• Successful test in Aug. 04

SQ
TQS
4
Motivations and goals (SQ02)Conductor test

• Provide a means of evaluating conductor and cable
  under operating conditions similar to the TQ

Istrand Bpeak Stresses
TQ 460 A 11.3 T 100-150 MPa
SQ 490 A 11.1 T 100-150 MPa
5
Motivations and goals (SQ02)Training studies

• Validate numerical models related to magnet
  performance
• Perform training and quench initiation studies
• 3D FE model of the magnet geometry
• Axial forces
• Investigate dependence of magnet performance on
  axial loading

Fz total Acoil ?z
TQ 350 kN 4300 mm2 81 MPa
SQ 340 kN 3900 mm2 87 MPa
6
Motivations and goals (SQ02)Technology
development

• New coil parts
• Different assembly procedures
• Quench propagation study
• Cable characterization and comparison with
  modeling
• Field quality measurements
• Coil alignment with shell-type structure
• Coil fabrication tolerances
• Strain gauge RD
• Data analysis with different data acquisition
  systems

7
Outline

• Motivations and goals
• Magnet design
• SQ02 SQ02b
• Overview
• Design features and axial load
• Test results
• Conclusions and next steps

8
Magnet designSuperconducting coil

• Cable
• 0.7 mm strand
• 20 strands, 7.9 X 1.3 mm
• Insulation 0.1 mm fiberglass
• Racetrack coils
• Double-layer
• Iron / bronze island (pole)
• 20 turns per layer
• Horseshoe / end shoe containment structure
• Aluminum bore
• Clear aperture 110 mm
• Coil aperture 130 mm

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Magnet design Support structure

• Stainless steel pads
• Iron yokes
• Aluminum shell
• Thickness 22 mm
• Outer diameter 500 mm
• 4 bladders and 8 keys for assembly and pre-load
• Axial support
• 4 aluminum rods
• Diameter 25 mm
• Stainless steel end plate
• Thickness 50 mm
• Pre-load applied with hydraulic cylinder
• Strain gauges on shell and rods

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Outline

• Motivations and goals
• Magnet design
• SQ02 SQ02b
• Overview
• Design features and axial load
• Test results
• Conclusions and next steps

11
SQ02 overview

• Progress to date
• June Aug. 05
• Fabrication of 4 new coils
• Sept. 05
• Assembly (Initial axial load)
• Oct. 05
• Test at LBNL (SQ02)
• Dec. 05
• Re-load (Higher axial load)
• Mar. 06
• Test at FNAL (SQ02b)
• Next step
• End of FY06
• Re-load (Lower axial load)
• Test (SQ02c)

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SQ02 Design features

• Test of TQ conductor and cable
• Four new coils
• SC17-SC16-SC18-SC19
• Training studies
• Tests with different axial load
• 3D FE models
• Coils instrumentation
• 1 spot heater
• 4 strain gauges
• 10 voltage taps
• Technology development
• New horseshoe design and bronze island
• Improved assembly procedure (axial load first)

13
SQ02Short sample limits

• Calculated short sample (extracted strand meas.)
• Iss (4.3 K) 9.9 kA
• Bpeak (4.3 K) 11.1 T
• Iss (4.5 K) 9.8 kA
• Iss (1.8 K) 10.8 kA
• Peak field in the end region
• 2 T difference between ends and straight
  section

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SQ02Axial load

• Measured axial rod tension
• After assembly
• 70 MPa (150 kN)
• After cool-down
• 120 MPa (260 kN)
• Computed gap coil-island
• Friction model (µ 0.2)
• Separation allowed
• 80 mm gap at short sample

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SQ02 test resultsConductor and magnet performance

• First thermal cycle
• 1st quench
• 5.9 kA (60 Iss)
• 90 in 13 quenches
• Highest quench
• 9.4 kA (95 Iss)
• Second thermal cycle
• 1st quench
• 9.4 kA (95 Iss)
• Highest quench
• 9.6 kA (97 Iss)
• Bmax 10.7 T
• Gmax 81 T/m

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SQ02 test resultsQuench locations

• All quenches in the innermost turn
• Training quenches
• Trend from end segments to central segments
• Short sample quenches
• End segment (coil 18)

• Training quench location
• ? Short sample quench location
• ? Voltage tap

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SQ02 FE model Frictional energy dissipation
Fy
Fz

• Friction factor ? µ (0.2)
• Sliding distance ? ? m
• Contact frictional stress ? ? N/m2
• Frictional energy dissipation per unit area ? ? ?
  J/m2

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Frictional energy dissipation J/m2 6000 A ?
7000 A
19
Frictional energy dissipation J/m2 7000 A ?
8000 A
20
Frictional energy dissipation J/m2 8000 A ?
9000 A
21
Frictional energy dissipation J/m2 9000 A ?
10000 A
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SQ02bAxial load

• Measured axial rod tension
• After assembly
• 130 MPa (290 kN)
• Similar force as TQS01
• After cool-down
• 190 MPa (410 kN)
• Computed gap coil-island
• Friction model (µ 0.2)
• Separation allowed
• 40 mm gap at short sample
• 50 reduction with respect to SQ02

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SQ02b test resultsConductor and magnet
performance

• 4.5 K
• 1st quench
• 9.1 kA (93 Iss)
• Highest quench
• 9.5 kA (97 Iss)
• Similar as second thermal cycle at LBNL
• 1.8 K
• 1st quench
• 9.8 kA (90 Iss)
• Highest quench
• 10.6 kA (98 Iss)

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Outline

• Motivations and goals
• Magnet design
• SQ02 SQ02b
• Overview
• Design features and axial load
• Test results
• Conclusions and next steps

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Conclusions

• SQ series has been a successful RD program
• Cable and conductor evaluation
• TQ01 conductor achieved 97-98 of calculated Iss
  (both at 4.3 K and 1.8 K) without significant
  degradation due to stress
• Training studies
• Analysis of quench initiation and location
  through instrumentation consistent with numerical
  predictions
• Study of the effect of axial load on magnet
  performance
• Work in progress
• Technology development
• Improved assembly procedure (implemented in TQS)
  and new coil parts (same pole material as TQ)

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Next steps (SQ02)

• Retest with lower axial load (SQ02c)
• Comparison between SQ02b and SQ02c magnet
  performance
• Analysis of the effect of axial load on trained
  magnets
• Significant increase in computed end gaps

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Next steps (SQ03)

• Cable and conductor evaluation
• Fabrication of 4 new coils with RRP conductor
  (TQ02)
• Training studies
• Feed-back on mechanical analysis
• Analysis of effect of axial load on magnet
  performance
• Comparison with SQ02 (virgin magnet)
• Technology development
• New material for the island