Prospects for High Temperature Superconducting Magnets David Larbalestier National High Magnetic Field Laboratory, Florida State University, Tallahassee FL NHMFL User Committee Meeting October 2, 2009 YBCO properties: Aixia Xu, Fumitake Kametani, Jan Jaroszynski, Youri Viouchkov YBCO coil R+D and test: Ulf Trociewitz, Huub Weijers, Patrick Noyes, Bill Shepherd, Ken Pickard, Denis Markiewicz Bi-2212 Coil and test: Ulf Trociewitz, David Myers, Jianyi Jiang, Eric Hellstrom, Huub Weijers, Patrick Noyes YBCO conductor by SuperPower (Venkat Selvamanickam, Yi-Yuan Xie, Drew Hazelton and colleagues) Bi-2212 conductor by Oxford Superconducting Technology (Yibing Huang, Hanping Miao and colleagues) and processing by Jianyi Jiang, Tengming Shen, Michael LoSchiavo, Eric Hellstrom)

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 2 Themes (November 2008) All superconducting high field magnets provide a technology pull for HTS conductors The needed conductors are now here and have been tested in small coils made at the MagLab to B > 30T An all superconducting user magnet has been designed (~32 T, 34 mm 4K bore) The January NSF Major research instrumentation program provides a vehicle to seek funding for such a magnet

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 3 Some words from the 2008 User Committee report “The prospect of an all-superconducting 32 tesla magnet is very exciting. This could reduce operating costs while allowing more measurements to be done, particularly for fixed field measurements such as NMR and specific heat, and indeed this is an exciting development for the field as a whole. “

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 4 January 2009 Major Research Instrumentation (MRI) Program Submission MRI: Development of a 32 T All-Superconducting Magnet System using YBa 2 Cu 3 O 7-x Coated Conductors PIs: Denis Markiewicz and David Larbalestier, (National High Magnetic Field Laboratory, Florida State University), and Stephen Julian (Department of Physics, University of Toronto). The Intellectual Merit of Our Goals: Our goal is an all- superconducting 32 T magnet. The enabling technology is YBCO (YBa 2 Cu 3 O 7-x ) thin-film coated high temperature superconductor (HTS-CC) which has just become available in km lengths. YBCO CC offer the possibility of transforming superconducting magnet technology, because its 4 K critical fields are well above 100 T, compared to the 30 T of Nb 3 Sn from which magnets can only made with maximum fields of about 22 T.

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 5 32 T Magnet Parameters Total field 32 T Field inner YBCO coils17 T Field outer LTS coils15 T Cold inner bore 32 mm Uniformity 5x cm DSV Current186 A Inductance436 H Stored Energy7.54 MJ YBCO Nb 3 Sn NbTi Good news – fully funded at $2 million over 3 years starting 10/09 – talk by Denis Markiewicz on the tour

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 6 The Global Context is provided by COHMAG- Opportunities in High Magnetic Field Science – 2004 Grand magnet challenges: 30T NMR (All SC) 60T Hybrid (R + SC ) 100T Long Pulse (R) All require materials in conductor forms that were not available in 2004 They now are! Means: ….the involved communities [users and magnet builders] should cooperate to establish a consortium whose objective would be to address the fundamental materials science and engineering problems that will have to be solved…….. COHMAG report 2004

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 7..and locally by user demands, the power bill, and the NSF budget…. Provides the world’s highest magnetic fields 45T DC in hybrid, 32 mm warm bore Purely resistive magnets: 35T in 32 mm warm bore, 31 T in 50 mm bore and 19T in 195 mm warm bore 20 MW resistive magnet ~$2400/hr at full power

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 8 HTS greatly extends the capability at 4K Courtesy Peter Lee

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 9 YBCO Coated conductor by SuperPower (Guilderland NY) – available since mid 2007 Phenomenal Jc in the YBCO - ~20 x 10 6 A/cm 2 at 25T YBCO is ~1% of cross-section 50% is high strength superalloy 2  m Ag 20  m Cu 50  m Hastelloy substrate 1  m HTS ~ 30 nm LMO ~ 30 nm Homo-epi MgO ~ 10 nm IBAD MgO < 0.1 mm

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 10 YBCO Test Coils – ’09 update SuperPower I. Bmax = 26.8 T ΔB = 7.8 T SuperPower II. Bmax = 27 T ΔB = 7 T NHMFL I. Bmax = 33.8 T ΔB = 2.8 T NHMFL II. Bmax = 20.4 T ΔB = 0.4 T

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 11 Bi-2212 round wire technology too – layer winding, cablable conductor Bi2212 Ag-sheathed conductor before heat treatment Bi-2212 filaments after heat treatment Round wires enable cabling into the high current conductors needed for large magnets or fast ramp magnets Arno Godeke Magnet Group, LBNL

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 12 HTS insert coil trends – ’09 update year B A +B HTS =B total [T] J ave [A/mm 2 ] Stress [MPa] J ave xB A xR max Stress [MPa] J e xB A xR max BSCCO 20+5=25 T (tape) 20+2=22 T (wire) 31+1=31 T (wire) YBCO- SP =26.8 T YBCO-NHMFL =33.8 T YBCO -SP = YBCO-NHMFL (strain limited) = ~611  39 mm YBCO SP 2007  87 mm  163 mm Bi-2212  38 mm Summary by Weijers

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 13 An HEP Collaboration to develop round wire 2212 conductor and coil technology (Arup Ghosh (BNL), David Larbalestier (FSU), and Alvin Tollestrup (FNAL)) - funded August ‘09 at $4 million over 2 years Conductor understanding (PIs – Eric Hellstrom (NHMFL) and Terry Holesinger (LANL) Conductor mechanical properties – Najib Cheggour (NIST) and Arno Godeke (LBNL) Cable development – Emanuela Barzi (FNAL) and Al McInturff (TAMU/LBNL) Quench analysis – Soren Prestomon (LBNL) and Justin Schwartz (NCSU) Coil Development – Ulf Trociewitz (NHMFL) and Arno Godeke (LBNL) Industrial conductor development – Ken Marken (LANL) and Arup Ghosh (BNL)

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 14 Rutherford and Roebel cables needed for large magnets Predicted perp. field Ic of 15 strand, 5 mm wide Roebel YBCO cable – parallel 5-7 times higher Arno Godeke, Magnet Group, LBNL Bi-2212 YBCO – Nick Long (IRL) and Andrew Priest (General Cable NZ) Rutherford cable (flattened, fully transposed cable) works well for round wire 2212 Major task of the HEP collaboration YBCO tape cannot be Rutherford cabled but cabling by the Roebel method is possible Under evaluation by Karlsruhe and General Cable and IRL (NZ)

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 15 Developing the case for a long term R&D effort Magnet-pull focus NMR HTS coil 40 T small HTS coil (31 T background) Finding the limits (stress, energy density, quench….) High current cables (e.g. Zeemans) Conductor-pull focus YBCO coated conductors are evolving rapidly driven by 40-77K, 0- 3 T use – what about 4 K, T properties? Bi-2212 is round wire and multifilament – but has intrinsically poor vortex pinning due to large electronic anisotropy 2212 and YBCO have 3 times the critical fields of Nb 3 Sn but their conductor technology is still primitive…. What we really want are the vortex pinning properties of YBCO and the grain boundary properties of 2212 Why not…………..?

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 16

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 17 Timelines and Progress 2006 – Renewal proposal takes up the COHMAG challenge 2007 – experimental concentration on 2212 and formation of HEP collaborations, first joint SP-NHMFL YBCO coil Definition of the key problems of the conductor technology and formation of a focused attack on the issues New benchmark for a superconducting magnet – 26.8T 2008 – parallel paths for YBCO and 2212 now clearly warranted 32 T all superconducting MRI proposal rejected on technicality (too many from FSU) Multilab 2212 proposal submitted from Fermilab (PIs – Larbalestier and Alvin Tollestrup – BNL/FNAL/LANL/LBNL/NHMFL/NIST New world record small magnets of 2212 (32T) and YBCO (33.8T) 2009 – recognition that our R&D program was indeed promising $2M MRI for 32 T awarded (10/09 start, PIs Markiewicz, Larbalestier and Steve Julian) $4M awarded by DOE-HEP over 2 years to evaluate the coil-readiness of Bi (6/09 start) PIs Larbalestier and Alvin Tollestrup (Fermilab) with multilab efforts at BNL, FNAL, LANL, LBNL, NHMFL and NIST

David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 David Larbalestier NHMFL User Committee Meeting, Tallahassee FL November 2-3, 2009 Slide 18 Bi-2212 round wire coil (Trociewitz, Weijers, DCL on Oxford 2212) conductor reached 32.1 T in 31 T background coil specs: 15 mm ID, 38 mm OD 100 mm high 10 layers, 750 turns, 66 m  B = 1.2 T at 31 T L ~ 1 mH first HTS wire-wound coil to go beyond 30 T slight discoloration of braid at enclosed feed-through “regular” HT, no visible leaks 15mm spiral results before HTafter HT