Basic Research Magnetization AC Loss and Quench in

Basic Research Magnetization, AC Loss, and Quench in YBCO Cables” DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325. 1

Modelling and Measurement of Magnetization of YBCO CORC and Roebel Cables for Accelerators CORC Samples: Mike Sumption, M. Majoros, C. Myers, D. Van Der Laan Advanced and E. W. Collings Conductor Center for Superconducting and Magnetic Technologies and Materials, MSE, The Ohio State University of Colorado NAVY Applied Superconductivity Twisted Strand: Workshop, April 2016 University of Houston This work was supported by the U. S. Department of Energy, Office of Science, Division of High Energy Physics, under Grant DE-SC 0011721 and an AF Summer Faculty

OSU Magnetization Rigs Magnetization Measurement Facilities: A number of options are available, some systems better suited to given samples or given test requirements DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

MAG-0: 14 T, 2 K-RT PPMS Quantum Design Physical Property Measuring System (PPMS) equipped with a 14 T superconducting magnet and temperature control from 1. 8 K to 400 K, can measure: M-H, AC susceptibility, AC transport, DC transport, Thermal conductivity, Hall effect, Heat capacity. Used to measure Nb 3 Sn M-H loops and magnetizations, as well as those of Bi: 2212 strand DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

MAG-1: 4. 2 K, +- 12 T Magnetization rig MAG-1, for samples larger than can be measured in the PPMS, but smaller than use for MAG-2. This is a susceptibility rig type magnetometer inside of a 12 T cryocooled magnet. Inside the 3” diameter room temperature bore is a varitemp dewar with a magnetization insert (b) side view, (c) face view. A current of up to 200 A can be applied to samples which are being measured for MH. Figure A 6. 2. Magnetization rig MAG-1, for samples larger than can be measured in the PPMS, but smaller than use for MAG-2. This is a susceptibility rig type m DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

MAG-2 Cable Magnetization measuring facility (Magnet arrived early Feb 2016, assembly underway); (a) 3 T coil (Cryomagnetics design and made), Nb. Ti wound, 150 amperes, Inductance of 10 milli. Henries. Clear bore is 5. 5 cm total length 30. 48 cm. (b) Drawing of coils, homogeneity on-axis is +/- 5% over 15 cm, (c) radial field homogeneity. DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

3 T Magnet Max Field = 3. 1 T Max I = 90 A L=1 H Max Ramp Rate = 70 m. T/s DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

MAG-3: Screening loss rig • M-H and AC Loss device for 77 K measurements of YBCO, with typical sample shown above (YBCO CORC cable in this case). • External-Field M-H and AC Loss is measured in the applied fields of copper wound solenoids and race-track coils of various sizes. • A system of pick-up coils connected to a digital oscilloscope records the samples' M-H loops • Used in this program for screening and as a comparison/calibration measurement at 77 K Also 77 K, SF is like 20 T, 4 K DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

hysteretic YBCO CORC cable losses tape Penetration field increases for cables made from tapes– a shielding effect CORC cable from Tape Complicated helical geometries DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

SAM-AC Loss A radial and tangential field is generated The field is approximately sinusoidal We can measure samples as small as a cm segment of tape, as well as lengths of cable and small coils The system can apply a field of 0. 5 T at 13600 RPM and 540 T/s Shown below is a 10 cm segment of 4 mm wide tape Bmax = 0. 56 T Here we have a comparison to solenoidal measurement DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

SAM-CORC If we consider a helically wrapped tape, then some of the time, B tape Sometimes, B // tape The hysteretic loss and magnetization of CORC above field penetration can be approximated by Tape loss * 2/ Average B tape is 2/ Then can we estimate AC loss and mag of CORC by tape*2/ ? Bmax = 0. 56 T As measured CORC * /2 DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Measurements on CORC at 77 K Of interest: Magnetization of striated tape Magnetization of striated and twisted tape Magnetization of striated and unstriated tapes on CORC Re-estimate of error field estimates DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Measured Loss in Striated and Twisted YBCO– Universit of Houston tape samples Un-Striated width = 12 mm length = 16. 1 cm Thickness = 70 µm Striated and Twisted

YBCO, Striping, Twisting Sample 1: Striated Sample 2: Not Striated Sample 3: Striated and Twisted Measurements made on University of Houston Samples 50 Hz, Bmax = 0. 1 T Striations + Twisting needed for magnetization reduction DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Striated measurement results 77 K Striations do significantly reduce loss Some factor from striation, some from Ic loss DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

FEM Modelling Initial approach 1. Model to start as model of one helix, then moving to multiples Jc values are representative of 4 K, 0 T 2. Treat the SC film as distributed DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Modelling Treatment Composite, 250 m SC, 1 m Substrate, 50 m M = CJcd Msc = msc/Vsc= CJcd Let Je=Jc/ff Mcomp = Msc/Vcomp = Msc/(Vsc*ff)=msc. Jcd/ff=msc. CJed Penetration field, Bp = CJcd So, only OK if renormalization is in same dimension as d So we can treat the current as flowing through the whole composite and get a proper M DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Calculation for 1 strand CORC cable (4 K) DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Comparison loss shape to model AC loss of sample R 3 at 50 Hz in liquid nitrogen bath (77 K) FEM model prediction DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.

Summary • Various magnetization rigs are in operation and also commissioning • Under construction – 3 T, 4 K AC loss rig capable of 25 cm YBCO cable samples • Magnetization measurement, modelling, and comparison to accelerator targets underway • Measurements of Striated CORC cables show significant magnetization Reduction • Measuring of Twisted striated samples (With Uo. H) show magnetization suppression, as expected DISTRIBUTION C. Distribution authorized to U. S. Government Agencies and their contractors; Critical Technology; 19 APR 2016. Other request for this document shall be referred to NSWCPD Code 325.