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Linear Collider Detector Magnet
Project
R&D activity on a new superconducting cable
for a 5T, 6m bore coil.
B. Curé - A. Gaddi / CERN Physics Dept.
Linear Collider
Conductor overview
Atlas CS
5T, 5 layer
18kA, 40 strand cable
Atlas BT
CMS
Atlas ECT
Rutherford SC cable
Pure Al stabilizer
Reinforced Al stabilizer
AA reinforcement
B. Curé - A. Gaddi / CERN Physics Dept.
Heating, brushing & straightening racksB. Curé - A. Gaddi / CERN Physics Dept.
Co-extrusion press at Nexans
Short term plan
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Our R&D plan is to co-extrude a section of 57x12mm2 (using Atlas BT punch and die).
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We now refurbish the cable preparation tools (heating and brushing units). We have tons of pure aluminum
billets available. We have CMS and ATLAS cables with km available. We need to check if a 40 strand cable can
be used at Nexans.
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We have reshaped (forging, butt welding with EB, and machining) the billets kindly provided by Prof. Yamamoto
to the dimensions requested for the press of Nexans-Cortaillod, Switzerland. Available quantity allows to get
about 100m with the cross section of 57x12mm2.
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Plan is to co-extrude one of the available cables from ATLAS or CMS. (32 or 40 strand cable): 100m with pure
aluminum then 100m with Al-0.1wt%Ni.
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The pure aluminum part of the conductor would be used for reference and set up of the cold work line (not
identified yet).
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For a 5-T coil as proposed in the frame of the LCD working group, the final conductor overall dimensions would
be about 98x16mm2 (either with Al-Ni alone or reinforcement alloy welded to Al-Ni).
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The Rutherford cable would be with 40 strands.
B. Curé - A. Gaddi / CERN Physics Dept.
Discussion items
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Is there any specific co-extrusion conditions with Al-0.1wt%Ni, such as: co-extrusion temperature (430°C?),
extrusion speed, and cable preheating temperature? Do you know the Al-0.1wt%Ni flowing conditions as a
function of temperature and pressure, or other particular physical properties?
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The cable cross-section design depends on the large forces the conductor has to withstand. In our case, the coextruded cross-section will be 57x12mm. Do you have any experience in cold-working such large sections? Do
you see any problem with that (i.e. large drawing forces, incomplete cold-working at cable core, strand or cable
breakage…)? What could be a recommended Rutherford cable packing factor (compacting ratio)?
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At what temperature the cold-working has to be done? Does it depend upon the cable section or form-ratio?
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What is the cold-working set-up that you would recommend for this specific conductor? It seems the cold work
is done in several steps (5%, 10%, 15%, 20%)? Could it be done with either a rolling mill or drawing, followed
with a final shaping to get the requested corner radii either through a die or with machining.
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What is the effect of resin curing, after the winding is complete, on the mechanical characteristics of the
conductor? Do you expect a multi-layer coil would need a longer resin curing time?
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We plan to perform the following measurements on conductor and aluminum alloy samples after the coextrusion and cold working:
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1) yield and tensile strength at room and liquid helium temperature
2) RRR at liquid helium temperature
3) critical current at liquid helium temperature
4) Cable to stabilizer bonding
Do you have any other suggestion or important issue that is not shown here?
B. Curé - A. Gaddi / CERN Physics Dept.