Long Quadrupole Program Giorgio Ambrosio DOE Review of the LARP - - PowerPoint PPT Presentation

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Long Quadrupole Program Giorgio Ambrosio DOE Review of the LARP - - PowerPoint PPT Presentation

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BNL - FNAL - LBNL - SLAC Long Quadrupole Program Giorgio Ambrosio DOE Review of the LARP Program SLAC July 9-10, 2011 LQ Task Leaders: Fred Nobrega (FNAL) Coil fabrication Jesse Schmalzle (BNL) Coil fabrication Helene Felice (LBNL)

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SLIDE 1

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 1

Long Quadrupole Program

Giorgio Ambrosio

DOE Review of the LARP Program SLAC

July 9-10, 2011

LQ Task Leaders: Fred Nobrega (FNAL) – Coil fabrication Jesse Schmalzle (BNL) – Coil fabrication Helene Felice (LBNL) – Structure Maxim Marchevsky (LBNL) – Instrumentation and QP Guram Chlachidize (FNAL) – Test preparation and test BNL - FNAL - LBNL - SLAC

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SLIDE 2

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 2

Outline

  • Main features
  • Practice coils

— Lessons learned

  • LQS01a

— Results — Lessons learned

  • LQS01b

— Results — Lessons learned

  • LQS02

— Results — Lessons learned

  • LQS03

— Plans

  • Budget and conclusions
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SLIDE 3

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 3

LARP Magnet Development Chart

2004-06 2005-10 2008-13 2011-15

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SLIDE 4

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 4

Long Quadrupole†

Main Features:

  • Aperture:

90 mm

  • magnet length: 3.7 m

Target:

  • Gradient:

200 T/m Goal:

  • Demonstrate Nb3Sn magnet scale up:

— Long shell-type coils — Long shell-based structure (bladder & keys) Deadline: by the end of 2009

† LQ Design Report available online at:

https://plone4.fnal.gov/P1/USLARP/MagnetRD/longquad/LQ_DR.pdf

LQS01 S.S.L. 4.5 K Current 13.7 kA Gradient 240 T/m Peak Field 12.25 T Stored Energy 460 kJ/m — Reproducibility, training memory, and performance at 1.9K

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SLIDE 5

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 5

LQ Features

  • LQS is based on TQS (1m model) with modifications for

long magnets

  • Structure Modifications:

– Added tie-rods for yoke & pad laminations – Added masters – Added alignment features for the structure – Rods closer to coils – Rods made of SS

Aluminum shell

Cross-section of TQ/LQ coil

  • Coil modifications:

– LQ coils = TQ coils with gaps to accommodate different CTE during HT – From 2-in-1 (TQ coils) to single coil fixtures (LQ) – Bridge between lead-end saddle and pole – Mica during heat treatment

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SLIDE 6

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 6

Practice Coil – Lessons Learned

  • Several issues found during Practice Coils fabr.

— bowing, longitudinal tension in coil, damage to leads, incomplete impregnation, damage to insulations

  • All issues and causes have been addressed:

More QC, more detailed travelers Discrepancy reporting

Fewer discrepancies going forward in production

 More robust fabrication technology

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SLIDE 7

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 7

LQS01a Quench History

Test report available online at: https://plone4.fnal.gov/P1/USLARP/MagnetRD/longquad/report/TD-10-001_LQS01_test_summary.pdf 200 A/s

SSL at 4.5K : 240 T/m Target: 200 T/m

  • Slow start

— First quenches at high ramp rate (200 A/s) — Slow training at 4.5K

  • Due to low pre-load on

pole turns

  • Faster training at 3K

— Reached 200 T/m

  • Stopped training

— to avoid coil damage and to achieve better performance with optimal pre-stress

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SLIDE 8

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 8

LQS01a - Lessons Learned

  • Coil oversize not accounted for in structure assembly,

caused non optimal prestress  CMM measurements of all coils  Adjustment of coil-structure shims for optimal preload  Procedures for checking at warm proper coils-structure matching

Nominal Oversized LQS01b LQS01a

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SLIDE 9

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 9

LQS01b Quench History

At 4.5 K: reproducible quenches in coil #8  G = 222 T/m; Iq/Ic = 92 ssl At 1.9 K: variable quench curr. in coil #9  limited stability of conductor SSL at 4.5K : 240 T/m Target: 200 T/m 227

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SLIDE 10

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 10

LQS01b Quench History 2nd Therm. cycle

1st quench: G = 208 T/m 2nd quench G = 222T/m with controlled cooldown DT < 100 K

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SLIDE 11

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 11

LQS01b Magnetic Measurement

Average harmonics in the TQS and LQS at 45 T/m (~ 2.6 kA) at the ref. radius r0 of 22.5 mm

† G. Velev, et al., “Field Quality Measurements and Analysis of

the LARP Technology Quadrupole Models”, IEEE Trans. On Applied Supercond. , vol.18, no.2, pp.184-187, June 2008

LQ does not have alignment features. They are in HQ (1m) and will be in LHQ (~4m).  Field quality of long Nb3Sn magnets will be demonstrated by LHQ

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SLIDE 12

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 12

LQS01b - Lessons Learned

  • LQS01b reached the best performance of all TQS02

series (1m models with same conductor)!

  • Demonstrated good training memory

We know how to make long Nb3Sn coils without degradation Segmented shell structure can be used for long Nb3Sn magnets with shell-type coils We have tools (computation & instrumentation) for protecting long Nb3Sn magnets

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SLIDE 13

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 13

LQS01b To Be Improved

  • Some “bubbles” on coils

inner layer

— Coil-insulation separation

  • Plans:

— Strengthen insulation (coil 13) — Change/remove inner layer heaters

  • Big voltage spikes at low

current (flux jumps)

  • No expected Gradient

increase at 1.9 K Smaller filament diam. in LQS03 coils 54/61  108/127

Maximum Voltage Spike amplitude at 4.5 K with 50 A/s ramp rate

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SLIDE 14

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 14

LQS02 Quench History

Limited performance “Reverse ramp-rate dependence”

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SLIDE 15

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 15

LQS02 Analysis

  • Holding quenches, Voltage Tap data, Quench Antenna

data, and Spike Recording System data confirmed:

  • The cause is “Enhanced Instability” in one coil

— An unknown “issue” causes a decrease of the stability threshold of the conductor in coil 13 OL. — Possible “issues” are: (i) a local damage or a non-uniform splice forcing more current in a few strands; (ii) a damage of some strands decreasing the local RRR and/or causing filaments merging.

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SLIDE 16

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 16

LQS02 - Lessons Learned

  • There are “issues” that we cannot detect during fabrication
  • r assembly, which may limit magnet performance
  • These “issues” decrease the instability threshold of the

conductor We need to understand the cause of these “issues”

 We have demonstrated that over-compression is one, …

We need more stability margin

LQS03 coils have 108/127 RRP with higher stability margin than 54/61

We need to understand coils yield

So far in LQ we tested 7 good coils out of 8

We need to plan for possible reassembly during production

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SLIDE 17

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 17

LQS03

  • Four new coils with RRP 108/127
  • Same target prestress of LQS01b
  • Slightly improved coil-structure matching wrt to LQS02

Ready for test

 Cooldown starts in two weeks

  • GOALS:

— exceed 200 T/m at 4.5 K — exceed 220 T/m at 1.9 K — demonstrate training memory after unrestricted cooldown

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SLIDE 18

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 18

Post LQS03

LQS03 meets goals

Analysis of cause

LQ is done!

LQS03b addressing issue

yes no

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SLIDE 19

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 19

LQ Budget

  • LQ actual budget profile (in $K)

— conductor cost/coil put 2 yrs. in advance of coil fabrication

Coils # 5 5 2 5 17 FY06 FY07 FY08 FY09 FY10 FY11 FY12 TOTAL LQ conductor 435 435 174 435 1479 LQ all but cond. 130 610 3789 3149 1926 1824 508 12347 565 1045 3963 3584 1926 1824 508 13826

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SLIDE 20

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 20

Conclusions

  • The Long Quadrupole is demonstrating Nb3Sn scale-

up to ~4 m

— Target gradient with LQS01a; — Matched the best performance of all short models with LQS01b — Demonstrated good memory with LQS01b 2nd thermal cycle

  • We have learned a lot, also by addressing unexpected

issues

— LQS03 should demonstrate that we are back on track

  • There some open questions that will be addressed by

the rest of the program

— LHQ will demonstrate good field quality in long Nb3Sn magnets

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SLIDE 21

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 21

Backup Slides

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SLIDE 22

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 22

LQ Fabrication Process

  • Cable:

—Cabling: LBNL —Qualification tests: BNL, FNAL, LBNL

  • Coils:

—Wind & curing: FNAL —Reaction & impregnation, BNL, FNAL —Instrumentation: BNL, FNAL, LBNL

  • Structure:

—Pre-assembly & magnet assembly: LBNL

  • Test:

—Warm and cold test: FNAL

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SLIDE 23

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 23

LQS01b (same coils of LQS01a)

  • More uniform prestress distribution in the coils

By using thinner coil-pad shims

  • Higher preload based on 1m models (TQS03 a/b/c)

 Peak load: 190 MPa +/- 30  No coil-pole separation in LQS01b

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SLIDE 24

LARP DOE Review, 7/9/2012 Long Quadrupole – G. Ambrosio 24

LQS01b: 220 T/m in 4 quenches LQS01b: 222 T/m 92% ssl based on strand test (95% ssl based on cable test)

Gradient at 4.4K of LQ & all 1m models with RRP 54/61