Magnet Technology for Nuclear Magnetic Resonance from DC Powered Magnets to Prospects for High Temperature Superconducting Magnets

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1 Magnet Technology for Nuclear Magnetic Resonance from DC Powered Magnets to Prospects for High Temperature Superconducting Magnets Na#onal Science Founda#on State of Florida Winter School, 2018

2 Our long range vision is set by National National Research Council Routinely Generates Reports on High Magnetic Field Science Academy Panels Both are free downloads they provide good descriptions of: COHMAG MagSci og/11211/opportunitiesin-high-magnetic-fieldscience g/18355/high-magneticfield-science-and-itsapplication-in-the-unitedstates 1. the science being done with high magnetic fields 2. the science that could be done with newer facilities 3. A description of the technology status 4. A rationale and list of desired new facilities NRC reports do not provide money only a hunting license!

3 Superconducting NMR Magnets : Where are we going? B [T] Tesla = MHz for 1 H NMR LTS/HTS NMR Magnet Program [GHz] : Superconducting LTS [MHz] : COPPER [MHz] CMU (Bruker) 1.02G NIMS 0.7G (Phase 2) 1.36G NHMFL 1.3G MIT 1.1G (Bruker) G (Phase 1) Bruker 1.0 GHz Year Slide credit: Y Iwasa via R. Griffin Iwasa@jokaku.mit.edu

4 The First DC Magnet Optimized for NMR: The 24.6 T Keck Magnet Constructed in mm warm bore 1 H Frequency: 1066 MHz 2 Soghomonian, Cotten, Rosanske, Cross (1997) J Magn Reson 125:212. Gan, Kwak, Bird, Cross, Gor kov, Brey, (2008) J Magn Reson, 191:135

5 Enhanced Homogeneity: Current Density Grading End Turn and Middle Turn Florida BiUer Plates Each blue rectangle represents a stack of biuer plates. The current density in the Keck is highest in the inner coil for efficient use of energy. The reduced current density near the center of field in Coil B is to enhance homogeneity

6 Water and Current Flow in the Bitter plate stacks Current Flows down through the inner stack, up through the middle stack and down through the outer stack. Middle stack is wound in the opposite helical sense to the other two stacks. Powered by 12.6 MW at 35.5 ka Water flows through all three stacks simultaneously. Cooled by 4500 L/min of 8 C deionized water Water exits magnet at 35 C

7 HEteroNuclear PhasE Correction (HENPEC) Spectroscopy Using the single sharp line of 2 H to record the actual Magnet Field vs Time Ethanol Spectrum using HENPEC Gan et al. (2008) JMR 191:

8 First (& last) Attempt at 45T Hybrid 9Al 2 O 3 + 2B 2 O T 40T Z. Gan, P. Gor kov, T. Cross, A. Samoson, D. Massiot J Am Chem Soc, 124(2002)

9 SCH: Cable-in-Conduit Conductor Nb 3 Sn carries current when Superconducting Steel supports the Lorentz forces Liquid Helium stabilizes SC (Absorbs >100 W dc power) Typically a 30 min ramp to full field Cu carries Current if Quench 50 mm, RT bore 12.5 MW DC power 720 grams/min LHe (1.8K) 1800 gal /min water (283K) 13 T SC Outsert 23 T Resistive Insert 36 T Hybrid Ground Plane Insulation Corner Filler Main Coil mm Nb3Sn/Cu Conduit Interlayer Cloth 1.8 mm mm

10 Enhanced Homogeneity: Current Density Grading The current density in the SCH is the result of extensive calculations to maximize the homogeneity at the center of field. A major enhancement over the early effort to enhance homogeneity of the Keck magnet. Jack Toth, NHMFL

11 20 ka, N 2 -Cooled HTS Leads Bi2223 Bi2223 Marshall, Bai, Bird, Bole, Dixon, Gavrilin, Miller, Napier, Noyes, den Ouden, Perenboom, Weijers, White, Wulfers

12 The Superconducting Outsert Construction and Installation

13 Energizing the SCH for the First Time: At least 10 laptops Monitoring many different pieces of this complex magnet Inter- Coil Structure Cryostat SCH Res/Mag Protec#on Power DC Field Ops/ Training Cryogenics

14 NMR at Fields Up To 36 T Field Maps: Base Field & Ini>al Ferro & Resis>ve Shims T 1.2 GHz 1 H Frequency B o ppm Posi>on vs. B o Center Field stability without and with Bruker Lock T Magnet Cell with Avance Neo Bruker console. B(t) /ppm B(t) /ppm expansion of red curve in plot below 1 H Channels at 1.0, 1.2 & 1.5 GHz 1 ppm over a 1 cm diameter cylinder achieved 2/9/17 Stability of beuer than 0.2 ppm Meet Mul#ple specifica#ons before the magnet had been at field for more than 25 hours time /s

15 Temporal Instability as Measured in 3.2 mm Triple Res MAS Probe Locked (0.14 ppm) ppm Pietro Lendi, Zhehong Gan, Ivan Hung, Xiaoling Wang Time (s)

16 Currently Three Probes for 1.5 GHz: Triple- resonance 2.0 mm HXY MAS probe. Double- resonance HX sta#c probe. Single- resonance 3.2 mm MAS probe. The external lock rf coils located underneath the top PC board in 2.0 mm and sta#c probes; and in the stator of the 3.2 mm probe. 1.3 mm and 0.75 mm MAS triple resonance probes are planned Peter Gor kov, Jason Kitchen Gan et al., JMR, 2017 (hups://doi.org/ /j.jmr )\

17 Resolution in Quadrupolar Nuclei: Single Resonance Probe ISSN Volume 284, November Al 2 O 3 + 2B 2 O 3 36 T SCH Cutaway illustration of the new 36T magnet at the US National High Magnetic Field Laboratory a hybrid using a low temperature superconductor outsert in series with resistive Bitter discs. The series connection results in an enhanced, sub-ppm stability compared to conventional powered magnets, enabling solid state NMR investigations like the shown 17O 2D MQMAS NMR spectrum of 17O labeled benzoic acid obtained at 35.2 Tesla (1H frequency of 1500 MHz). Gan et al. (2017) JMR 284: T Hybrid Gan et al. (2008) JMR 191:135

18 Quadrupolar Spectroscopy in the SCH 17 O Quadrupolar Central Transi#on spectra of [3,5,6-17O]- D- glucose in glycerol acquired at 270 K using 0.01 s recycle delay - Gang Wu, Queen s # scans: mm MAS Single Frequency Probe 17 O 3QMAS spectrum of benzoic acid at 35.2 T. Q shearing was used 8192 In color are the second- order line shapes for each site. Gang Wu, Queen s Zhehong Gan, Ivan Hung, Xiaoling Wang Gan et al., JMR, 2017 (hups://doi.org/ /j.jmr )

19 1D & 2D 17 O Spectroscopy at 35.2 T of U- 13 C, 15 N, 70% 17 O] N-Ac-VL MAS Rate 19 khz 3QMAS spectrum with centerbands highlighted 17 O 3QMAS spectrum of benzoic acid at 35.2 T. Q shearing was used MAS Rate: 19 khz Keeler et al. Griffin, R.G., JACS, in press (2018)

20 Oriented Sample of 15 N Gly2,Ala3 Gramicidin A Joana Paulino Ivan Hung Gan et al., JMR, 2017 (hups://doi.org/ /j.jmr )

21 17 O Gramicidin A Spectroscopy at 21 T Oriented Sample 17 O Gramicidin A - solva>on of monovalent ca>ons by this ca>on channel in DMPC Bilayers ppm linewidths in absence of ca>ons. Considerably Amazing temperature dependence in the presence of ca>ons

22 Gramicidin A 17 O-Leu 10 in DMPC P:L Molar Ratio 1:16 at 30 C gramicidin A 17O-Leu10 in DMPC P:L 1:16 at 30C acquired on supercon 19.4T 500K scans blue - no ion red M KCl green M LiCl 35.2T (1500 MHz) Blue: no ion Red: no ion, 1 H decoupling 6 ppm water Supercon Spectroscopy Blue: no ion Red: 2.4 M KCl Green: 2.4 M LiCl 35 ppm O Chemical Shift (ppm) Joana Paulino, Ivan Hung Ed Chekmenev. Vanderbilt Univ.

23 Triple Res MAS Probe Circuit Peter Gor kov

24 First 13 C MAS Spectra in Triple Res Probe 0.17 ppm linewidths for single scan adamantane linewidths of 0.4 ppm in GB1 60 Hz issues should be solved in the next few months Gan et al., 2017 JMR 284:

25 Current 13 C MAS Spectra in 2.0 mm MAS Triple Res Probe Enhanced Sensi#vity in the DARR spectrum linewidths of 0.4 ppm in GB Hz is the primary limita#on 24.4 khz MAS HXY: 2 scans /t1 increment 91 min total acquisi#on Zhehong Gan, Ivan Hung, Xiaoling Wang

26 Current 1 H- 13 C HETCOR Spectra of GB khz 2.0 mm MAS HXY Probe: Future: 1.3 & 0.75 mm MAS Probes Stators in hand Probes in Development Zhehong Gan, Ivan Hung, Xiaoling Wang

27 Resolution Enhancement in 13 C Spectra 36 T SCH ChiZ from M. tuberculosis part of the divisome Resonances are significantly narrower But spectral signal to noise is lower from lack of signal averaging #me

28 Magnet Conductor Choices 2. RRP (150/169 design) very high J c Nb 3 Sn conductorthousands of few µm dia. Nb filaments in pure Cu converted to ~ 40 µm filaments after reaction with Sn cores, easily cabled to make ka conductors 1. Nb47Ti conductor- thousands of 8 µm dia. Nb47Ti filaments in pure Cu, easily cabled to operate at ka < 0.1 mm 20µm Cu 50µm Hastelloy substrate 20µm Cu 4. REBCO coated conductor highest J c obtained by biaxial texture developed by epitaxial multilayer growth 5. Bi-2212 high J c in isotropic form without macroscopic texture! The first HTS conductor like an LTS conductor. 3. Bi-2223 the first HTS conductor high J c requires uniaxial texture developed by deformation and reaction 2 µm Ag 1 µm HTS ~ 30 nm LMO ~ 30 nm Homo-epi MgO ~ 10 nm IBAD MgO

29 Why New Materials are Needed for the Next Generation of Magnets Low T Superconductors J c, Cri#cal Current Density, is a func#on of Field, Temperature, Strain, Mechanical Strength and Wire Piece Length. High T Superconductors Ceramics Wire vs. Tape But the poten#al!!

30 Even the Nb 3 Sn is a sophisticated material the result of a complicated process NbTi is used for the outer coils up to a field strength of ~9T Most useful as multi-filamentary composites Because Nb3Sn is very brittle the wires must be processed to small final diameters while the Nb and Sn elements are separate The Nb3Sn alloy is formed by a high temperature reaction treatment typically at 650 C for as long as 100 hours. Typically the coil is wound from the unreacted wire while it is still ductile, then the entire coil undergoes reaction Of course the insulation must remain intact during this process Used up to fields of 23.5 T

31 To get above 24T we need HTS materials: Three Choices - #A Bi2223: (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10-x A Tape powder-in-tube method; T c = 110K - high quality magnets have been made - while a high critical current density, it is highly anisotropic

32 To get above 24T we need HTS materials: Three Choices - #B Bi2212: Bi 2 Sr 2 CaCu 2 O 8-x A Wire, T c = 90K - high critical current density and low anisotropy - has to be processed at a very high temperature just below the melting temperature of silver to avoid defects in the structure a high pressure of O 2 is required during the heat treatment

33 To get above 24T we need HTS materials: Three Choices - #C YBCO: YBa 2 Cu 3 O 7-d A Tape, T c = 92K - uses a substrate known as Hastelloy or a Ni-W alloy (in figure it is labeled substrate ) providing a high tensile strength - Strong anisotropy leads to problems at the ends of coils for NMR magnets, which are very long to generate a homogenous field

34 Comparison of LTS and HTS Conductor Performance LTS conductors - Essentially zero drift essentially perfect homogeneity Shimming an HTS magnet maybe challenging - for LTS magnets the low order gradients are corrected by coils on the outside of the main magnetic field coils - for HTS coils the screening of the currents in the HTS coils makes shim coils less effective or even ineffective - may have to use ferro shims on the inside of the bore Stability early reports from a YBCO coil stated that the half-life of the drift when the magnet was energized was ~600 days. - tricks and new techniques are being developed Joints superconducting electrical joints need to be made - rumors of Bi2212 joints exist and the joint technology used for LTS conductors maybe good enough - Bruker claims to have joints for the YBCO that are better than they expected

35 1.02 GHz HTS/LTS Magnet 3.6 T of Bi T of the outer LTS coils of the former 920 MHz Magnet 24 T in total a powered magnet system that achieves good stability and lineshape Unfortunately, the magnet destruc#vely quenched. Fig. 4. Stability of a single shot 1 H spectrum of 1% CHCl 3 in acetone-d 6 with the internal lock for 10 h. mm Hashi et al., JMR 2015 Fig H spectrum of CHCl 3 in aceton-d 6.

36 32T all HTS (ReBCO) User Magnet in Development High-B coils 31 T + B 320 mm Prototype coils under test 20% of 32 T REBCO coils Development: YBCO tape characterization & QA Insulation technology Ceramic on co-wound SS tape Coil winding technology Joint technology Quench protection analysis Extensive component testing Quench heater Demonstration insertshigh Hoop-stress coils 20 T+ B >760 MPa Heater-only quench protection First Quench Heaters Mark 1: 1 st test coil Mark 2: 2 nd test coil : 1 st Full-featured Prototype : 2 nd Full-featured Prototype

37 Winding Pancake Disks on a Lathe; Preparing for Joints; and HTS Double Pancakes Stacked for the Magnet

38 HTS coil in an LTS Background and Cryostat: Operational at 32 T 15T LTS + 17T HTS Remarkably Stable Raw Field HTS component 32 cm high Tesla Field azer 20 min Ramped: 30T - > > 32T field after 20min Time (s) Time (s) Shift (ppm) ppm - 63 Cu NMR in sample in 2 (32T all sup H o = o / = FWHM = Cu NMR of metal- lic Cu powder ob- served in cryogenic condi#ons o = MHz Frequency (MHz)

39 HTS Magnets are Coming & with them Exciting Science will Follow Note the small size of the HTS coil The GdBCO tape wound as a pancake Shaking Coil novel concept for damping the long term drift Low order shims in the interior of the magnet Iwasa s efforts for NMR have been supported by NIH for many years The Series Connected Hybrid is giving us a preview into the future of high field NMR with: 1) enhanced sensitivity; 2) enhanced dispersion & resolution; 3) an opportunity to observe much of the periodic table HTS magnets are on the way and with them will be incredible opportunities for understanding the chemistry of materials and biological systems: 30, 40, 50, 60 T. Iwasa et al., IEEE Trans Appl Supercond, 2015