Superconducting Strand and Cable Studies for Nb3Sn High Field Dipole Magnets

1
Superconducting Strand and Cable Studies for
Nb3Sn High Field Dipole Magnets
VLHC Magnet Technologies Workshop Fermilab, May
24-26, 2000

• Emanuela Barzi

2
Outline

• Target requirements for Nb3Sn
• Where are we? Work in progress on
• Strand characterization
• Cable optimization
• Can we improve performancies?
• HT times ? Breakthrough for Internal Tin
• Jc, deff, stability
• Conclusions

3
Target Requirements
W/Cu to non-Cu1.2 10-20 Degradation 15 Margin
Jc gt 3000A/mm2 Deff lt 30-40 micron Piece length
gt 1 km Cu to non-Cu up to 1.5 As short as
possible reaction cycles As cheap as possible
4
Strand Description
5
Jc vs. B
6
Low Field Magnetization
3-0-3 T Hysteresis Loops _at_ 1T/min.
7
Effective Filament Diameter
deff - 1.0 mm strands OST 114 - 121 ?m IGC 89 -
142 ?m PIT 54 ?m
8
Cable Samples for Cos-Theta
Cable Short Samples Number of strands 28 Keystone
Angle 0.91deg Cable width 14.24 mm Mean
thicknesses 1.706-1.885 mm SS core 0.02512
mm2
Packing Factor range 85-95
9
Ic Cabling Degradation
10
Common Coil Rectangular Cables
11
Nb3Sn - State of the art
12
Heat Treatment Optimization -1
Jc
13
Heat Treatment Optimization -2
Magnetic Stability
14
Conclusions

• More work

15
Is deff a geometrical parameter?