Fermilab Energy Frontier Meeting, Feb 26, 2019 High - temperature superconductors and accelerator magnets for energy frontier colliders : Opportunities , challenges , and advances Tengming Shen Lawrence Berkeley National Laboratory Material shown here drawn from work conducted by * Support by US DOE-High Energy Physics (HEP) , US LBNL staff and students in the Berkeley Center for Magnet Technology, Applied Physics and Accelerator DOE Fusion Energy Science, and US DOE-SBIR/STTR. Technology Division, and collaborations with FNAL, BNL in the LHC-AUP and US MDP partnerships, National High Magnetic Field Laboratory (supported also by NSF), ACT, Bruker OST, nGimat LLC, and CERN. UNIVERSITY OF CALIFORNIA 1
Charges from Dmitri S Denisov, Fermilab Hi High T c cuprate a and i iron based s superconductors: w : what i is p potential, w , what a are limitations, w , what i is e expected c cost, w , what i is t the m market f for c cables m made o of s such sup super ercond nduc uctor? "100 T TeV pp pp co collide der" - ho how realistic i is t to u use H HTS sup super ercond nduc uctors s and w what m might be c cost r reduction i in c comparison w with Nb Nb-Ti Ti and N Nb 3 Sn Sn? 2 2
100 years of superconductivity, 60 years of superconducting magnets, 30 years of HTS Discovery and understanding mechanisms and magnetic properties of superconductors • 1911 – Discovery of superconductivity • 1957 – Type II superconductors and Abrikosov vortex Heike K Kamerlingh On Onnes • 1957 – BCS theory • 1961 – High-field superconductivity in Nb 3 Sn • 1962 – Josephson effect • 1983 – Tevatron – the first large application of superconductivity • 1980s - MRI • 1986 – High temperature superconductivity • 2008 – LHC • 2026 – ITER – first plasma Engineering and practical applications 4 3
HTS supplies 3-4x higher H c2 or H irr Higher fields require HTS – unlike LTS (Nb-Ti and State of the art 1 GHz Nb 3 Sn NMR magnet in Lyon. France Nb 3 Sn) there are 3 choices of conductor and 4 in persistent state at 23T magnet construction choices H c2 (0) is only 30 T 4 4 Credit – David Larbalestier, NHMFL/FSU
HEP goals have strong synergy with fusion goals and magnets demanded by high-magnetic-field science Very s strong s synergy be between HEP g goals ( (fu future 1 100 T TeV c circular h hadron c collider) a and fu fusion goals (Tokamaks b go beyond IT ITER e e.g .g. . DEMO o or s small c compact m machines) MagSci Goals (2013 NRC report) Consider regional 32 T superconducting magnets at 3-4 locations optimized for easy user access. Establish at least 3 US 1.2 GHz NMR instruments for broad access and plan ~1.5 GHz class system research and development Establish high field (~30 T) facilities at neutron and photon scattering facilities Construct a 20 T MRI instrument (for R&D with Na, P etc) Design and build a 40 T all - superconducting magnet Design and build a 60 T DC hybrid magnet that will capitalize on the success of the current 45 T hybrid magnet in Tallahassee 5 5 Credit – David Larbalestier, NHMFL/FSU
Commercially available magnet conductor choices 2. R RRP ( (150/169 d design) v very h high J J c Nb Nb 3 Sn Sn few µ m d co conduct ctor- thousands o of f dia. N Nb f filaments i in One US manufacturer. 40 µ m f pure C Cu c converted t to ~ ~ 4 filaments a after r reaction with S Sn c cores, e easily c cabled t to m make 1 10-20 k kA co conduct ctors 2 µ m A 2 Ag 1 µ m H 1 HTS ~ 3 30 n nm L LMO ~ 3 30 n nm H Homo-epi M MgO 1. N Nb47Ti c conductor- thousands o of 8 8 20 µ m C 20 Cu ~ 1 10 n nm I IBAD M MgO µ m d dia. N Nb47Ti f filaments i in p pure C Cu, easily c cabled t to o operate a at 1 10-100 k kA Credit – David Larbalestier, < 0.1 mm 50 µ m H NHMFL/FSU 50 Hastelloy s substrate 20 µ m C 20 Cu 4. R REBCO c coated c conductor – highest J J c obtained b by b biaxial t texture d developed Three US manufacturers, with different by e epitaxial m multilayer g growth architectures and processing technologies 5. B Bi-22 2212 2 – high J J c in i isotropic f form w without m macroscopic t texture! T The One US manufacturer. first H HTS c conductor l like a an L LTS c conductor. 3. B Bi-2223 2223 – the f first H HTS c conductor – high J J c requires u uniaxial t texture developed b by d deformation a and r reaction Not produced in US. 6 6
GBs are the Achilles Heel of cuprates 𝜊 = ℏ𝜉 𝐺 • Small coherence length(nm) makes HTS 𝜌Δ , Δ ∝ 𝑈 𝑑 very sensitive to local defects on nanometer ⟹ 𝜊 ∝ 1/𝑈 𝑑 scale v GB is an obstacle to supercurrent. v IBM group was the first to demonstrate the significance of grain alignment for REBCO. GB beyond a v A fast, exponential decay of J c small critical angle: • Planar bi-crystals Dimos et al., PRB, 41(4038), 1991 Critical angle q c ~3 o • q = - q q GB J ( ) J exp( / ) c 0 c Fundamental requirement for high current density is elimination of all but very low angle grain boundaries 7 7 Credit – David Larbalestier, NHMFL/FSU bi-crystal
Biaxially textured REBCO conductors by the km length today – an extraordinary materials engineering activity - but at a cost of $50-100/m Epitaxial, multilayer, thin-film growth IBAD – Fujikura and Stanford Uni. Cu Cu Ag YBCO 8 8
Three ideas to get to 20 T (CERN + US MDP) 1. REBCO ROEBEL Aligned Block Superconducting dipole hall-of-fame (modified from a graph by Luca Bottura, CERN) and collaborators 2. CORC CCT For HL LHC CCT with stress 3. Bi-2212 Rutherford, block or CCT management capability. 9 9
The real challenge of high magnetic fields – mechanics, materials at limits, and protection Why does stored energy matter? Credit – Luca Bottura, CERN 10 10
Technical challenges with HTS conductors (optimized so far for performances, not for magnets) Quench – detection and protection – high stability Manage stress and strain and of HTS leads to zero propagation hot spot mechanical damages Detection voltage <10 cm Tied to each other in an interesting way. V = 𝐾 1 𝜍 𝐶, 𝑈 1 𝑚 Good field quality (time and space) – Dealing with inhomogeneity (REBCO) screen currents (Credit of Y. Sogabe, Kyoto Uni.) 11
Bi-2212, the only HTS round wire, is now a magnet-grade conductor. Wire J e reaches 1000 A/mm 2 at 27 T. LBNL subscale magnet performance OPHT + NEW conductor 10000 /powder 9000 RC-06 8000 RC-05 7000 I c or I q (4.2 K) (A) RC-03 6000 RC-02 5000 RC-01 1 bar HT 4000 x 2.3 HTS-SC-08 3000 HTS-SC-10 2000 HTS-SC-06 HTS-SC-04 1000 0 2006 2008 2010 2012 2014 2016 2018 A homogeneous, isotropic HTS conductor Year • Nano-spray combustion powder. J e - 1365 A/mm 2 at 15 T, twice the target • desired by the FCC Nb 3 Sn strands J e - 1000 A/mm 2 at 27 T, adequate for 1.3 • Zhang et al. SuST, 31 (2018) 105009 GHz NMR. Jiang et al., IEEE TAS, 29 (2019), 6400405 12 12 Shen et al., arXiv preprint arXiv:1808.02864
HTS Bi-2212 coils can be fast ramped: High stability against AC losses 9000 RC6 Quench current (A) 8000 RC5 7000 RC3 RC2 6000 RC1 5000 US LARP 3.7 m Nb 3 Sn long racetrack LQS 0 30 60 90 120 150 180 210 Ramping rate (A/s) Zhang et al. SuST, 31 (2018) 105009 Shen et al., arXiv preprint arXiv:1808.02864 13 13
HTS Bi-2212 coils are high-stability superconducting magnets with a predictable quenching behavior – a “clock” magnet with I q reliably produced • Training, detraining, and A “ “clock” m magnet unpredictability of Nb 3 Sn magnets RC6 RC RC-3 CERN 1 11 T T N Nb 3 Sn d dipole Predictable, quench detectable (way ahead of time), and avoidable. Shen et al., arXiv preprint arXiv:1808.02864 Shen et al., Stable, predictable operation of racetrack coils made of high-temperature superconducting 14 14 Bi-2212 Rutherford cable at the very high wire current density of more than 1000 A/mm 2 . under review
Magnetic confined fusion – races for compact fusion power plant now fueled by big private investments ($60 million [US alone] on HTS magnets and conductors in next 3 years) ITER IT Nb 3 Sn for higher field Reactor-class devices Plasma density x16; Bx2 Commonwealth fusion systems (MIT + CFS) No blanket; no electricity generation ITER 20 IT 2015 Fusion Fu • Compact: R 0 < 2m B co coil = 1 13 T T • High-field: B 0 ~ 12T, B max ~ 21T (HTS) Fusion power: 100 MW • Fusion gain: Q>2 • 15 15
NMR technology at cross-road - >1 GHz NMR only available with HTS. Superconducting wind generator technology faces fierce competition from permanent magnet technology; NP and HEP applications other than p - p colliders lack a market pull. Muon C Capture S Solenoid f for J-PARC M MLF S Second T Target Credit – S. Hahn, Seoul Nat. Uni./NHMFL Credit – Toru Ogitsu, KEK A4 A3 Particle-beam t Pa therapy A2 Acrylic Japan MIRAI, 1.3 GHz NMR, $40 million/10 years (H. Maeda); Fabricated coils cylinder @ Toshiba Keihin Factory Ax Axion on dark m matter s search >10 MW, off-shore, direct drive superconducting wind generators Nuclear p physics – ECRIS IS Eco-Swing [EU] – World’s first • Nb Nb-Ti V VENUS 2 28 G GHz superconducting wind turbine on • Nb Nb 3 Sn 4 45 G GHz i in p pursuit. grid and producing power (Dec • HTS a at 2 20 K K f for 3 37.5 .5 G GHz o or 8 84 G GHz a at 2018) 4.2 .2 K K 16 16 16
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