Subscale quadrupole (SQ) series Paolo Ferracin LARP DoE Review FNAL June 12-14, 2006.

Subscale quadrupole (SQ) series

Paolo Ferracin

LARP DoE Review

FNAL

June 12-14, 2006

Paolo Ferracin06/13/2006

Outline

• Motivations and goals

• Magnet design

• SQ02 & SQ02b• Overview• Design features and axial load• Test results

• Conclusions and next steps


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


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


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


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 R&D

• Data analysis with different data acquisition systems


Outline


• Magnet design




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


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


Outline


• Magnet design




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)


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)


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


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 m gap at short sample


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


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


SQ02 FE model Frictional energy dissipation

• Friction factor µ (0.2)

• Sliding distance [m]

• Contact frictional stress [N/m2]

• Frictional energy dissipation per unit area [J/m2]

Fz

Fy


Frictional energy dissipation [J/m2] 6000 A 7000 A


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 m gap at short sample

• 50 % reduction with respect to SQ02


SQ02b test resultsConductor and magnet performance

• 4.5 K• 1st quench


• 9.5 kA (97 % Iss)• Similar as second

thermal cycle at LBNL

• 1.8 K• 1st quench


• 10.6 kA (98 % Iss)


Outline


• Magnet design




Conclusions

• SQ series has been a successful R&D 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)


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


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

Subscale quadrupole (SQ) series Paolo Ferracin LARP DoE Review FNAL June 12-14, 2006.

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