WP10.2 status Reported by L. Bottura and C. Senatore Meeting at - - PowerPoint PPT Presentation

WP10.2 – status

Reported by L. Bottura and C. Senatore Meeting at CERN, February 2nd, 2014

Overview of cable options

Result of the discussion on tape/cables

• Roebel

– Mechanical properties and response to loading – Manufacturing process for long length, compact cable geometry – Windability (difficult axis direction and matching the transposition to the curvature radius)

• Stacks

– Transposition, need and effect of lack of transposition – Effect of transverse forces on the twisting region

• All

– Impregnation and insulation effects on tapes (delamination, stress distribution) – Protection and need of copper – Striation (how much do we need ?) – Dummies for winding tests – Parallel/transverse field effects and interaction with magnet design

BSCCO Rutherford

• Strand parameters

– Strand diameter: 0.8 (mm) – Engineering current density (15 T, 4.2 K): 675 (A/mm2)

– BSCCO current density (15 T, 4.2 K): 1930 (A/mm2)

– Critical current (15 T, 4.2 K): 340 (A)

• Cable proposal:

– Number of strands: 22 – Cable width: 9.5 (mm) – Cable average thickness: 1.45 (mm)

– Keystone angle: 0.6 (degrees) – Thin edge: 1.391 (mm) – Thick edge: 1.517 (mm)

– Transposition pitch: 65 (mm)

• Cable critical current: 6700 (A)

REBCO Roebel – tape

• Target Tape parameters

– Tape width: 12 (mm) – Tape thickness: 0.1 … 0.15 (mm) – Engineering current density (15 T, 4.2 K): 450 (A/mm2) – Critical current (15 T, 4.2 K): ≈ 800 A – SC layer: 1…2 mm (TBD) – Cu layer: 30…50 mm (TBD) – Homogeneity and defects TBD to assess the effect of punching – Bonding strength (delamination issue)

Cut tape geometry

• Optimal geometry defined by KIT

t g p a Status at KIT: t= 5.5 mm g= 1 mm α = 30 ° p=126, 226, 426 mm

R = 1-2 mm to reduce stresses , see C. Barth, et al. Supercond. Sci. Technol. 25 (2012) 025007

By courtesy of A. Karlo, ITEP KIT

REBCO Roebel – wide (block coil)

• Number of tapes (-)

15

• Cable width (mm)

12

• Cable thickness (mm)

1.2

• Transposition pitch (mm)

226

• Critical current (Bperp) (kA) 5

REBCO Roebel – KIT “stock”

• Transposition 226 mm

– 15 tapes (only SC)

• cable thickness: 1.1 mm
• critical current with 10% degradation:

5030 A

• Transposition 426 mm

– 28 tapes (only sc)

• cable thickness: 2.1 mm
• critical current with 10% degradation:

9390 A

– 27 superconducting tapes and 27*0.15 mm Cu

• cable thickness: 4.2 mm
• critical current with 10% degradation:

9054 A

– 14 superconducting tapes (loose cable)

• critical current with 10% degradation:

5350 A

By courtesy of A. Kario, ITEP KIT

REBCO Roebel – narrow (cos-q coil)

• Number of tapes (-)

8 15

• Cable width (mm)

10 10

• Cable thickness (mm)

0.44 0.88

• Transposition pitch (mm)

126 226

• Critical current (perp) (kA) 1.7 3