Wire and Cable for the HTS Test Facility

Wire and Cable for the HTS Test Facility Magnet Ian Pong (ipong@lbl. gov) Lawrence Berkeley National Laboratory

Outline • • • Introduction Requirements and Desired Characteristics Options Considerations Milestones / Decision Points 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 2

Introduction • About LBNL facility • We have made a range of cables types and design Ø Ø Ø Nb-Ti, Nb 3 Sn, Bi-2212; Rutherford type (capacity: 60 strands), 6 -around-1 With / without core With / without pre-cabling annealing Single-pass / 2 -pass (with intermediate annealing) Insulation: sleeve & tape (in-house), direct braiding (vendor) • Supporting a range of activities Ø Ø 2020 -06 -11 For LBNL Base Program MDP, LARP AUP, WFO Total number of cables in past 5 years: >80 Approximately: ~20 km or ~4 tons Value-added ~$3. 5 M Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 3

TFD Requirements and Desired Characteristics • Wire o High current at high field (to reach magnet bore field 16 T at 1. 9 K, plus margin -2 and accounting for “non-wire space”): non-Cu JC ~1. 5 k. A mm at 15 T, 4. 2 K o High RRR: >150 (round wire), >100 (15% rolled) o Availability (procurement lead time and cost) • Cable o Magnet aperture (150 mm x 100 mm) and number of coil layers (2 x 2 of 4) desired cable width: ~25 mm x 4 o Cable mechanical stability and cable cross section aspect ratio number of strands and strand diameter: ~44 at ~1. 1 mm or ~48 at ~1. 0 mm, ~10% thickness reduction, typical cable twist angle 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 4

Wire Options and Supporting Reasons • Modified Hi. Lumi-1. 1 (108/127) o Supporting reasons: well characterized, considerable amount of data at 0. 85 mm for comparison and for estimating likely performance instead of specification performance Plot of BOST data by courtesy of L. Cooley o IC at 16 T, 4. 2 K (1 billet): 543 -551 A o Cu: non-Cu ratio: 1. 2 (nominal) • DEM-1. 1 (162/169) o o o Procured under FCC Study CDP spec IC at 16 T, 4. 2 K (several billets): 640 -716 A Cu: non-Cu ratio: 0. 9; Std Sn: 3. 4 Same Sub: higher wire IC, but lower Cu ratio Considerably higher cost 2020 -06 -11 Ian Pong Courtesy of S. Hopkins (CERN) HTS Cable Test Facility Magnet CDR: Conductor Options 5

Cable Options and Supporting Reasons • Single-pass with pre-cabling annealing versus Two-pass with intermediate annealing o Either option can reduce the amount of residual twist o Single pass is simpler than a two-pass cable, and the risk of causing excessive edge subelement shearing is less o No core • Relevant CERN & LBNL experience o CERN: FRESCA 2 (40 x 1. 0 mm); LBNL: LD/HD (51 x 0. 8 mm), NED (40 x 1. 25 mm) o 44 strands x 1. 1 mm has been done before at LBNL; challenging but manageable • Insulation: braid versus sleeve o Direct braiding with S 2 glass fibre, using one of the AUP approved vendors 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 6

Alternative Options • For analysis purposes, alternative options relevant to cables with smaller diameter wires are considered • The cable width will not change substantially, if at all • The LBNL cabling machine can make cables with up to 60 strands • Maximum length is limited by weight: smaller diameter wires but higher number of strands to maintain the same width will give longer maximum length due to lower thickness • Single-pass, coreless cable with pre-cabling annealing is preferred in any case • Insulation will be the same 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 7

Considerations • JC and Cu ratio – what are the ranges required by this magnet? o Note that JC and Cu ratio affects IC, whose specification will need to be average minus 3 sigma. Impact study on margins due to IC & RRR will be provided by Diego • Minimum length – depends on number of turns in coil o Impacts conductor cost o Cabling limit: 200 kg, equivalent to ~500 m of 44 x 1. 1 mm • Cost o Hi. Lumi-1. 1 cheaper than DEM-1. 1 • Note that: o Subelement size / magnetization requirements / twist pitch considered relatively unimportant within the typical ranges 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 8

Milestones and Decision Points • Cabling o Planning two cables back-to-back, same parameters, but using the Hi. Lumi 108/127 and the DEM-1. 1 wires to determine cabling characteristics, followed by mechanical testing (winding test at CERN) and XS RRR, and possibly IS (FNAL/NHMFL? ) ~August/September 2020 • Conductor Review in (September/October 2020) • Release of conductor specification followed by RFQ 2020 -06 -11 Ian Pong HTS Cable Test Facility Magnet CDR: Conductor Options 9