[PPT] - High - temperature superconductors and accelerator magnets for energy PowerPoint Presentation

SLIDE 1

Fermilab Energy Frontier Meeting, Feb 26, 2019

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High-temperature superconductors and accelerator magnets for energy frontier colliders: Opportunities, challenges, and advances

Tengming Shen Lawrence Berkeley National Laboratory

UNIVERSITY OF CALIFORNIA

*Support by US DOE-High Energy Physics (HEP) , US

DOE Fusion Energy Science, and US DOE-SBIR/STTR.

Material shown here drawn from work conducted by LBNL staff and students in the Berkeley Center for Magnet Technology, Applied Physics and Accelerator 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.

SLIDE 2

Charges from Dmitri S Denisov, Fermilab

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Hi High Tc 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

f 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 Nb3Sn Sn?

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SLIDE 3

100 years of superconductivity, 60 years of superconducting magnets, 30 years

f HTS
1911 – Discovery of superconductivity
1957 – Type II superconductors and

Abrikosov vortex

1957 – BCS theory
1961 – High-field superconductivity in

Nb3Sn

1962 – Josephson effect
1983 – Tevatron – the first large

application of superconductivity

1980s - MRI
1986 – High temperature

superconductivity

2008 – LHC
2026 – ITER – first plasma

Discovery and understanding mechanisms and magnetic properties of superconductors Engineering and practical applications

Heike K Kamerlingh On Onnes

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SLIDE 4

HTS supplies 3-4x higher Hc2 or Hirr

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Higher fields require HTS – unlike LTS (Nb-Ti and Nb3Sn) there are 3 choices of conductor and 4 magnet construction choices

State of the art 1 GHz Nb3Sn NMR magnet in Lyon. France in persistent state at 23T Hc2(0) is only 30 T

Credit – David Larbalestier, NHMFL/FSU

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SLIDE 5

HEP goals have strong synergy with fusion goals and magnets demanded by high-magnetic-field science

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Consider regional 32 T superconducting magnets at 3-4 locations

ptimized 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 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 go goals (Tokamaks b beyond IT ITER e e.g .g. . DEMO o

r s

small c compact m machines)

MagSci Goals (2013 NRC report)

Credit – David Larbalestier, NHMFL/FSU

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SLIDE 6

Commercially available magnet conductor choices

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1. N

Nb47Ti c conductor- thousands o

f 8

8 µm d

dia. N

Nb47Ti f filaments i in p pure C Cu, easily c cabled t to o

perate a

at 1 10-100 k kA

3. B

Bi-2223 2223 – the f first H HTS c conductor – high J Jc requires u uniaxial t texture developed b by d deformation a and r reaction

2 2 µm A Ag 20 20µm C Cu 20 20µm C Cu 50 50µm H Hastelloy s substrate 1 1 µm H HTS ~ 3 30 n nm L LMO ~ 3 30 n nm H Homo-epi M MgO ~ 1 10 n nm I IBAD M MgO < 0.1 mm

4. R

REBCO c coated c conductor – highest J Jc obtained b by b biaxial t texture d developed by e epitaxial m multilayer g growth

2. R

RRP ( (150/169 d design) v very h high J Jc Nb Nb3Sn Sn co conduct ctor- thousands o

f f

few µm d

dia. N

Nb f filaments i in pure C Cu c converted t to ~ ~ 4 40 µm f 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

5. B

Bi-22 2212 2 – high J Jc in i isotropic f form w without m macroscopic t texture! T The first H HTS c conductor l like a an L LTS c conductor.

Not produced in US. One US manufacturer. Three US manufacturers, with different architectures and processing technologies One US manufacturer.

Credit – David Larbalestier, NHMFL/FSU

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SLIDE 7

GBs are the Achilles Heel of cuprates

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v GB is an obstacle to supercurrent.

𝜊 = ℏ𝜉𝐺 𝜌Δ , Δ ∝ 𝑈𝑑 ⟹ 𝜊 ∝ 1/𝑈𝑑

Small coherence length(nm) makes HTS

very sensitive to local defects on nanometer scale v IBM group was the first to demonstrate the significance of grain alignment for REBCO. v A fast, exponential decay of Jc

GB beyond a

small critical angle:

Planar bi-crystals
Critical angle qc ~3o

) / exp( ) (

c GB c

J J q q q

=

bi-crystal Dimos et al., PRB, 41(4038), 1991

Fundamental requirement for high current density is elimination of all but very low angle grain boundaries

Credit – David Larbalestier, NHMFL/FSU

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SLIDE 8

Biaxially textured REBCO conductors by the km length today – an extraordinary materials engineering activity - but at a cost of $50-100/m

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YBCO Ag Cu Cu IBAD – Fujikura and Stanford Uni. Epitaxial, multilayer, thin-film growth

SLIDE 9

Three ideas to get to 20 T (CERN + US MDP)

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For HL LHC Superconducting dipole hall-of-fame

(modified from a graph by Luca Bottura, CERN)

1. REBCO ROEBEL Aligned Block
2. CORC CCT
3. Bi-2212 Rutherford, block or CCT

and collaborators

CCT with stress management capability.

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SLIDE 10

The real challenge of high magnetic fields – mechanics, materials at limits, and protection

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Credit – Luca Bottura, CERN

Why does stored energy matter?

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SLIDE 11

Technical challenges with HTS conductors (optimized so far for performances, not for magnets)

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<10 cm

Quench – detection and protection – high stability

f HTS leads to zero propagation hot spot

Good field quality (time and space) – screen currents Manage stress and strain and mechanical damages

V= 𝐾 1 𝜍 𝐶, 𝑈 1 𝑚 Detection voltage

(Credit of Y. Sogabe, Kyoto Uni.)

Dealing with inhomogeneity (REBCO)

Tied to each other in an interesting way.

SLIDE 12

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Nano-spray combustion powder.
Je - 1365 A/mm2 at 15 T, twice the target

desired by the FCC Nb3Sn strands

Je - 1000 A/mm2 at 27 T, adequate for 1.3

GHz NMR.

Bi-2212, the only HTS round wire, is now a magnet-grade conductor.

Wire Je reaches 1000 A/mm2 at 27 T.

2006 2008 2010 2012 2014 2016 2018 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

RC-06 RC-03 RC-05 RC-02 RC-01 HTS-SC-10 HTS-SC-08 HTS-SC-06 Ic or Iq (4.2 K) (A) Year HTS-SC-04 x 2.3 1 bar HT OPHT + NEW conductor /powder

LBNL subscale magnet performance

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A homogeneous, isotropic HTS conductor

Zhang et al. SuST, 31 (2018) 105009 Jiang et al., IEEE TAS, 29 (2019), 6400405 Shen et al., arXiv preprint arXiv:1808.02864

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HTS Bi-2212 coils can be fast ramped: High stability against AC losses

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30 60 90 120 150 180 210 5000 6000 7000 8000 9000

RC6 RC5 RC1 RC3 Quench current (A) Ramping rate (A/s) RC2

US LARP 3.7 m Nb3Sn long racetrack LQS

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Zhang et al. SuST, 31 (2018) 105009 Shen et al., arXiv preprint arXiv:1808.02864

SLIDE 14

Training, detraining, and

unpredictability of Nb3Sn magnets

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HTS Bi-2212 coils are high-stability superconducting magnets with a predictable

quenching behavior – a “clock” magnet with Iq reliably produced

RC RC-3

A “ “clock” m magnet

CERN 1 11 T T N Nb3Sn d dipole

RC6

Shen et al., Stable, predictable operation of racetrack coils made of high-temperature superconducting Bi-2212 Rutherford cable at the very high wire current density of more than 1000 A/mm2. under review

Predictable, quench detectable (way ahead of time), and avoidable.

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Shen et al., arXiv preprint arXiv:1808.02864

SLIDE 15

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)

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IT ITER 20 2015 Bco

coil = 1

13 T T Nb3Sn for higher field Reactor-class devices

Compact: R0 < 2m
High-field: B0~12T, Bmax~21T (HTS)
Fusion power: 100 MW
Fusion gain: Q>2

Commonwealth fusion systems (MIT + CFS)

Plasma density x16; Bx2

IT ITER

No blanket; no electricity generation Fu Fusion

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SLIDE 16

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Japan MIRAI, 1.3 GHz NMR, $40 million/10 years (H. Maeda);

>10 MW, off-shore, direct drive superconducting wind generators Eco-Swing [EU] – World’s first superconducting wind turbine on grid and producing power (Dec 2018)

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

Acrylic cylinder A4 A3 A2

Fabricated coils @ Toshiba Keihin Factory

Pa Particle-beam t therapy

Credit – Toru Ogitsu, KEK

Ax Axion

n dark m

matter s search Nuclear p physics – ECRIS IS

Nb

Nb-Ti V VENUS 2 28 G GHz

Nb

Nb3Sn 4 45 G GHz i in p pursuit.

HTS a

at 2 20 K K f for 3 37.5 .5 G GHz o

r 8

84 G GHz a at 4.2 .2 K K

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Credit – S. Hahn, Seoul Nat. Uni./NHMFL

SLIDE 17

Fe-based superconductors (FBS) – status and prospects

High intragrain 4.2 K Jc of 104 A/mm2 but intergrain

Jc an order smaller in practical tapes/wires.

Mostly limited by extrinsic GB current blocking

effects (oxygen and others, Kametani, FSU)

Strain sensitive.

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Yao, Ma, SuST, 32 (2019) 023002

Nb-Ti – a commodity - $1/kA-m at 4.2 K and 4 T. FBS (K-122) - potential to reach $2/kA-m at 4.2 K and 10 T

r 20 K, 5 T.
Low raw materials cost.
Birr(T) > 80 T at 4.2 K and >20 T at 20 K.

Lab R&D – longest length – 100 m. NOT commercially available.

(FBS raw materials cost - L. Cooley, FSU) 17

SLIDE 18

Summary

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HTS cannot compete on price with Cu and Al – so no electric utility use (beyond demonstrations) yet

A factor of 10 drop in price is possible.

But high magnetic field use is now demonstrated

The world’s highest field DC magnetic field is 45 T at the NHMFL (28 MW to generate 34 T inside a large 11 T Nb3Sn superconducting magnet). NHMFL’s 32 T all superconducting solenoid achieved full field.

Isotropic, uniform, and macroscopically untextured Bi-2212 round wires will be made into 25 T user magnets and >1 GHz high-field quality NMR soon. For a 100 TeV collider – HTS can give the best performance but doesn’t give the best cost performance yet.

But with important roles to play, even assuming that its cost will never compete with Nb-Ti.

Three technologies. > 15 T dipole magnet demo in 2-3 years, 20 T demo in 5-7 years.

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