Racetrack Coil Technology – G. Ambrosio 1 LARP DOE review – FNAL, June. 5-6, 2007 BNL - FNAL - LBNL - SLAC Racetrack Coil Technology (LR, SQ) & other Supporting R&D activities Giorgio Ambrosio LARP DOE Review June 5-6, 2007 Outline: - Small Magnets: status and plans - Long Racetrack: status and plans - Other Supporting R&D activities

Racetrack Coil Technology – G. Ambrosio 2 LARP DOE review – FNAL, June. 5-6, 2007 Small Magnets - Goals Provide a means of evaluating conductor and cable under operating conditions similar to the TQ Validate numerical models related to magnet performance Perform training and quench initiation studies Investigate dependence of magnet performance on axial loading Technology development: –New coil parts –Different assembly procedures –Strain gauge R&D –Data analysis with different data acquisition systems –Field quality measurements –Coil alignment with shell-type structure –Coil fabrication tolerances “Small racetracks and small quadrupoles based on these coils: 2-layer, 26 cm long”

Racetrack Coil Technology – G. Ambrosio 3 LARP DOE review – FNAL, June. 5-6, 2007 Small Quadrupoles (SQ) Aluminum shell –Thickness: 22 mm –Outer diameter: 500 mm Iron yokes Stainless steel pads 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

Racetrack Coil Technology – G. Ambrosio 4 LARP DOE review – FNAL, June. 5-6, 2007 SQ02 Loading and Quench History Study of end pre-stress effect on magnet training and performance SQ02 –After cool-down Shell: 95 MPa Rods: 125 MPa (270 kN) SQ02b –Increase of  z rod at 293 K Same as TQS01 at 293 K –After cool-down Shell: 95 MPa Rods: 190 MPa (415 kN) SQ02c –Removal of axial rods –After cool-down Shell: 95 MPa Note: Axial loading applied with minimum shell tension Effect on training: - very good memory (consistent with other Nb 3 Sn magnets)  a series of ‘virgin magnets’ should be used to study the effect on 1 st th. cycle - Effect on quench performance can be “disruptive” if end pre-load/support is not sufficient

Racetrack Coil Technology – G. Ambrosio 5 LARP DOE review – FNAL, June. 5-6, 2007 SQ02 Strain Analysis Strain on the pole turn during excitation Results on a path moving along the cable –From the end of the straight section to the tip of the island Model assumptions: –Fr coeff. 0.2 –Separation allowed Peak tensile strain –From 1500 to 4500  strain Peak compressive strain –From -500 to  strain Friction plays an important role (stick-and- slip), but … be aware of the cliff

Racetrack Coil Technology – G. Ambrosio 6 LARP DOE review – FNAL, June. 5-6, 2007 Short-Term Plans: SQ03 Fabrication and test of 4 new coils –108/127 strand Possible candidate for future magnets –Conductor evaluation in operational conditions similar to the TQ/LQ magnets Cabling degradation Transverse stress degradation Short sample current Coil fabrication: by September Test: Oct-Nov.

Racetrack Coil Technology – G. Ambrosio 7 LARP DOE review – FNAL, June. 5-6, 2007 Long-Term Plans PROPOSALS: SRK (FY08): small racetrack to test TQ/LQ keystoned cables Rad-Hard insul. R&D (FY09+): test SQ with rad-hard insulation & impregnation materials that can withstand the expected dose at Max luminosity

Racetrack Coil Technology – G. Ambrosio 8 LARP DOE review – FNAL, June. 5-6, 2007 Rad-Hard Insulation R&D Goal: Develop insulation/impregnation scheme that can withstand the expected dose at Max luminosity Plan A (present mat.)Plan B (new materials) FY07Develop plans, schedule, cost Select alternative material FY08 Q1-Q2 Prepare samples and fixtures FY08 Q3-Q4 Irradiation & tests FY09Small Quad Rad-Hard Insulation Workshop Fermilab, April 20, 2007

Racetrack Coil Technology – G. Ambrosio 9 LARP DOE review – FNAL, June. 5-6, 2007 Long Racetrack - GOALS 1.The main goal is to test long Nb 3 Sn coils  target is to reproduce performance of short coils  magnet performance (training, …) are NOT an issue 2.Coils will be tested in an Al-shell-based supporting structure (preloaded using bladders and keys) in order to verify the use of this concept for long magnets Coil layout: two flat double-layer racetrack coils Technology successfully developed at LBNL and successfully modified at FNAL From 0.3 m to 3.6m Performed at BNL Developed at LBNL

Racetrack Coil Technology – G. Ambrosio 10 LARP DOE review – FNAL, June. 5-6, 2007 SRS01 Description Two double layer racetrack coils. Coil total length m; straight section m. Total length with horseshoe fixture 0.3 m. 21 turns per layer, 42 turns total per coil. Coil and fixture same as SM coils. Two coils tested were configured as common coil. Cable was RRP 54/61, 0.7mm strand OD, Cu/non-Cu ratio 0.89.

Racetrack Coil Technology – G. Ambrosio 11 LARP DOE review – FNAL, June. 5-6, 2007 SRS01 Test Ramp rate dependence due to long twist pitch. Performance at 1 A/s shows successful tech. transfer

Racetrack Coil Technology – G. Ambrosio 12 LARP DOE review – FNAL, June. 5-6, 2007 LR Support Structure Aluminum shell –Single piece –Length: 3.6 m Iron yokes –50 mm thick laminations Iron pads –Half length (1.8 m) Stainless steel skins –Full length (3.6 m) Bladders Keys and shims –Half length (1.8 m)

Racetrack Coil Technology – G. Ambrosio 13 LARP DOE review – FNAL, June. 5-6, 2007 Assembly: tooling & procedures Support structure assembled at LBNL with dummy coils –Tooling and procedures performed very well Tested at BNL at 77 K Dummy coils removed and re-inserted at BNL  Support structure is ready to be used for LRS01

Racetrack Coil Technology – G. Ambrosio 14 LARP DOE review – FNAL, June. 5-6, 2007 Instrumentation for 77 K test Instrumentation of shell and dummy coils –Trace on shell –Strain gauges on dummy coils Six stations along z axis Measurements –Azimuthal and axial shell strain –Horizontal and axial coil strain Dummy coil strain gauge locations

Racetrack Coil Technology – G. Ambrosio 15 LARP DOE review – FNAL, June. 5-6, 2007 FEM analysis of shell strain Aluminum shell in tension after cool-down –Different thermal contraction of aluminum and iron –Friction between shell and yoke Different strain profiles depending on friction factor

Racetrack Coil Technology – G. Ambrosio 16 LARP DOE review – FNAL, June. 5-6, K test results Good agreement between measurement and FEM with 0.2 fr. coeff. Top-bottom asymmetry will be addressed during LRS01 assembly by using bladders on both bottom and top locations Longitudinal variation of azimuthal stress in the shell is within acceptable range ( MPa) High longitudinal tension in shell and dummy coils Shell axial stress (MPa) Shell azimuthal stress (MPa) Dummy coil axial  strain

Racetrack Coil Technology – G. Ambrosio 17 LARP DOE review – FNAL, June. 5-6, 2007 Coil Fabrication Coil Winding: –Winding machine completed. –Coil winding completed. Automatic winding and pneumatic pushers operated nicely. Coil looks good, electrical checks good.

Racetrack Coil Technology – G. Ambrosio 18 LARP DOE review – FNAL, June. 5-6, 2007 Coil Reaction –Oven fabrication and acceptance tests completed temperature uniformity and ramp rate met specs. Achieved +/- 3 deg C at 650 C. –LRS01 coils heat treatment completed

Racetrack Coil Technology – G. Ambrosio 19 LARP DOE review – FNAL, June. 5-6, 2007 Coil Impregnation –Fixture fabrication complete, heaters mounted and wired –Dummy coil sectioned and inspected after impregnation  very good! –Improved bonding between coil and protection heater –LRS01 Coils successfully impregnated

Racetrack Coil Technology – G. Ambrosio 20 LARP DOE review – FNAL, June. 5-6, 2007 Coil & SS Handling Support Fixture Lifting: –Fabrication of beams and collars complete. –Same beams lift react & impreg tooling.

Racetrack Coil Technology – G. Ambrosio 21 LARP DOE review – FNAL, June. 5-6, 2007 Plans SHORT TERM: LRS01 assembly and pre-load: June 12 –LBNL and FNAL people are planning to attend it LRS01 test start: last week of June LONG TERM: Depend on LRS01, TQ02s, LM02 performance –Have all parts and cable available for a new coil

Racetrack Coil Technology – G. Ambrosio 22 LARP DOE review – FNAL, June. 5-6, 2007 FNAL Long Mirror FNAL “Mirror magnet” is a cos-theta dipole where a coil is substituted by iron blocks Plan: 2m – 4m mirror magnets Front view of mirror magnet The plan is to base the scale-up on a well understood design and fabrication technology FNAL successfully fabricated several dipoles and mirror magnets Larger probability of success of the LQ by: Several features complementary to LRs  Diversity & Risk mitigation - conductor, keystoned cable, insulation, coil shape, use of wedges, mechanical structure, Start as soon as possible development and qualification of tooling and infrastructure for Long Quadrupole at FNAL (New 6-m long oven, …)

Racetrack Coil Technology – G. Ambrosio 23 LARP DOE review – FNAL, June. 5-6, 2007 LM01 Test Results LM01 (2m) reached expected SSL at 4.5K –SSL: ~21 kA with 10% degradation (PIT conductor) Similar training to HFDM03 –1m mirror with PIT conductor Some detraining at 1.9K under investigation LM02 (4m) test in Sept-Oct 07 Open marks show quenches in the leads

Racetrack Coil Technology – G. Ambrosio 24 LARP DOE review – FNAL, June. 5-6, 2007 Conclusions Small Magnets: –Useful tools for studying conductors, materials, fabrication issues  plan to continue Scale-up: –To date the scale-up efforts (LR and FNAL LM) are showing encouraging results; –LRS01 test by end of the month –LM02 test in Sept-Oct Long shell: –stress and strain in the long shell and in the dummy coils are in good agreement with FEM results assuming 0.2 fr. –Longitudinal variation of shell azimuthal stress is within acceptable range for the LR