Higher Magnetic Fields are on the Horizon: What Science will be Facilitated? When will all of this Happen?

Transcription

1 Higher Magnetic Fields are on the Horizon: What Science will be Facilitated? What is the Technology that will be make this Possible? When will all of this Happen?

2 High Temperature Superconductors for High Fields have become a viable technology MagSci Challenge: 30 T by 2020 Today: 23.5 T (1 GHz 1 H NMR)

3 Why New Materials are Needed for the Next Generation of Magnets J c, Critical Current Density, is a function of Field, Temperature, Strain, Mechanical Strength and Wire Piece Length. Low T Superconductors High T Superconductors Ceramics Wire vs. Tape But the potential!!

4 Even the Nb 3 Sn is a sophisticated material the result of a complicated process 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 compound 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 NbTi is used for the outer coils up to a field strength of ~9T

5 To get above 24T we need HTS materials 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

6 To get above 24T we need HTS materials Coating still shows eccentricity; h is now about 15 µm, which is with 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 YBCO: YBa 2 Cu 3 O 7-d A Tape, T c = 92K Coating thicknesses sampled from about 30 cm of - uses a substrate known as Hastelloy or a Ni-W alloy providing a high tensile strength conductor - Strong anisotropy leads to problems at the ends of coils for NMR magnets, which are very long to generate a homogenous field

7 To get above 24T we need HTS materials 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

8 We have been spoiled by NbTi and Nb 3 Sn Conductors The first and maybe for a log time the performance will not just our our current LTS magnets - Essentially zero drift - for solid state NMR 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 such coils makes them ineffective - will have to use ferro shims on the inside of the bore - if an HTS tape is used the shims maybe be different each time the magnet is energized. Reshimming with ferroshims?? Stability a report on 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

9 We have been spoiled by NbTi and Nb 3 Sn Conductors Joints unless superconducting electrical joints can be made the magnet will have to be attached to a power supply - really excellent power supplies have stability of ~1 ppm - however long ago at Carnegie Mellon the first 600 MHz instrument was installed (~1980?) it was not a persistent magnet yet linewidths of a ppb were obtained, since only a small amount of power was needed to maintain the field - rumors of Bi2212 joints exist - Bruker claims they have joints for the YBCO that are better than they expected they will be using in their 28T magnets. The bottom line is that we should be prepared, at least for the near future to have high field magnets with somewhat reduced performance in some of these areas

10 NMR/MRI Applications as a Function of B o Homogeneity & Stability B o Homogeneity & Stability Superconducting Magnets Series Connected Hybrid Magnet High-Res Resistive Magnets Std-Res Resistive Magnets

11 25T Keck Resistive Magnet built in 1996 Worse case senario 52mm bore size 39kA(24MW) 20ppm/ o C Field maps before and after ferromagnetic shim NMR signal with 4mm magic-angle spinning Bird, Gan, IEEE Appl Supercon, 12 (2002) Gan, Kwak, Bird, Cross, Gor'kov, Brey, J Magn Reson, 191 (2008) 135.

12 Compensating field fluctuations ~25ppb HO-CH 2 -CH 3 Field fluctuations can be corrected if a reference signal (D 2 O solvent) is acquired simultaneously and used for correcting the fluctuation to the 1 H signal phase.

13 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)

14 High Field Impacts for Quadrupolar NMR: Resolution and Sensitivity 27 Al NMR Boltzman factor B 0 Frequency B 0 Line narrowing B 0 Resolved spinning sideband ~20 gain in sensitivity from 9.4 to 19.6T (~400 in time) (6-17 O) Methyl a-d- Glucopyranoside 17 O NMR 2 hrs at 19.6T (NHMFL) 7 days at 9.4T (Grandinetti, Ohio State) Gan et al JACS (2002)

15 Ultra-High Magnetic Resonances: Opportunities for Novel Science

16 Advantages of High Magnetic Fields coupled with High Homogeneity and High Magnet Stability Enhanced Sensitivity for Magn. Reson., e.g. can be greater than B o 4 for quadrupole n Enhanced Resolution for Magn. Reson., e.g. enhancements can increase with dimensionality of the spectra New Physical Phenomena at High Field, e.g. new phases Altered Physical Phenomena at High Field, e.g. altered relaxation times in Magn. Reson. Different frequency regimes for Magn. Reson., e.g. important for characterizing dynamics Changed Relative Magnitudes of Spin Interactions for Magn. Reson., e.g. leads to substantial resolution enhancements, such as TROSY Increased Magnetic Susceptibility, e.g. enhanced Functional Magn. Reson. Imaging, e.g. improved alignment of diamagnetic, paramagnetic molecules and more.

17 Solid-state 2D NMR Correlation Spectra are Significantly Enhanced At High Fields MORE THAN ANTICIPATED Renault et al., Angew. Chem Chimeric KcsA-Kv1.3 in Lipid Bilayers 500 MHz 750 MHz 900 MHz Sperling et al., J. Biomol. NMR 2010 GB1 New resonances appear in these 2D 13 C- 13 C correlations: Peaks out of Blobs

18 In Combination with State-of the-art Probes X,Y 1 H HIV-1 Viral Capsid CA Protein Polenova et al., (2013) J. Am. Chem. Soc.

19 Proton-Detected Experiments Stand to Gain a LOT at Ultrahigh Fields 1 H- 13 C Correlation Spectrum of an SH3 Domain Reif et al., (2013 Acc. Chem. Res. 46:

20 Spectral Dispersion and Sensitivity for Natural Products, Metabolomics, etc. 1.5 mm HTS Probe for metabolomics natural products Ultrahigh field NMR can provide critical new insight into the composition of biological metabolomes in health and disease. A powerful new tool in the drug discovery pipeline New combinations with Mass Spec / Chromatographic methods for sorting complex biological mixtures

21 Mega-Proteins: Structure, Dynamics & Function from UHF NMR Elucidating function in the using methyl TROSY: conformational states (A, B, C) have been identified and the interconversion rates characterized. Doubling the field strength will lead to unique opportunities for making what is a heroic effort today, routine New opportunities such as Ca TROSY will also arise Rosenweig & Kay, Ann. Rev. Biochem N detection not such a big penalty

22 Intrinsically Disordered Proteins: The ultimate demand for spectral resolution in the hunt for residual structure News & Views by Chouard re: Ferreon et al., (2013) Nature

23 OS NMR of CrgA: A Membrane Protein IDR Residual Anisotropy Nascent Structure N- Terminus AA DC ACS Ser Val Asn Phe Thr Val Ser Ala Val Ser Arg Thr Met Val Val Gly Ser Ser N 1 H Dipolar Coupling (khz) 1 Phe Labeled in the IDR 9 Ala Sites Labeled 15 N Anisotropic Chemical shift (ppm) CrgA, the protein that recruits 5 other proteins to the M. tuberculosis divisome. Interhelical Loop AA DC ACS Ser Ala Ala Ile Gly Ser Ala Pro61 Thr Ala Leu Asn Trp Met Ala Leu Gly

24 In Situ (E. coli Membranes) vs. Isolated, Purified, Reconstituted (in Synthetic Bilayers): Full length M2 protein Miao et al.,(2012) Angew Chemie.

25 In Cell studies are unique and wonderfully well adapted for NMR but only at ultrahigh fields Superoxide dismutase 1 maturation in live human cells: Zn binding, homodimer formation, chaperone intervention, disulfide bond formation all observable at 15 µm, at 950 MHz (Banci et al, Nat. Chem. Bio 2013)

26 So do oriented sample BioNMR Experiments 900 MHz M2 Protein (22-62) from Influenza A Structure determined in uniformly aligned liquid-crystalline lipid bilayers Enhanced Alignment at high Fileds Sharma et al., (2010) Science 330:

27 A unique resource that only opens at Ultrahigh Fields: Quadrupolar NMR Dramatical increase in sensitivity and resolution for NMR quadrupolar nuclei partaking of crucial chemical and biochemical events: Structure, Catalysis, Energy 27 Al MAS spectra of A 9 B 2 compound (Gan et al., J. Am. Chem. Soc. 2002). Single site 17 O labeled gramicidin A in lipid bilayers samples uniformly aligned & spectra obtained at 19.6 T (Hu et al., J. Am. Chem. Soc. 2005

28 Again Understanding & Explaining Biological Function it s what NIH wants. Oriented Sample 17 O Gramicidin A - solvation of monovalent cations by this cation channel. - Goal is narrow linewidths and enhanced sensitivity - 1 ppm homogeneity and stability will be OK - The temperature dependence is very interesting and unexplained - 21T: 17 O 112 MHz - 36T: 17 O 208 MHz

29 In Vivo Chlorine and Sodium MRI Imaging of the Rat Brain at 21.1 T 35 Cl 20x less sensitive than 23 Na Biexponential Free Induction Decay Loss of 35 Cl signal large quadurpolar interaction High [Cl - ] in Rat Glioma correlates tumor progression V. D. Schepkin, M. Elumalai, Kitchen, J.A., C. Qian, P.L. Gor kov, & W.W. Brey (2013) MAGMA

30 Sliding Ring Coil for Neuroimaging in Verical Bore Magnets 21.1T mm id coil (a) In vivo rat brain (b) Multiple ex vivo mouse brains (c) Human brain section Alzheimer s patient diverse coil loading C. Qian, I.S. Masad, J.T. Rosenberg, M. Elumalai, W.W. Brey, S.C. Grant, P.L. Gor kov, (2012) J. Magn. Reson. 221: (c) (b) 1 cm (a) 4 1

31 Relaxation Enhanced Ultrahigh Field 1 H Magnetic Resonance Spectroscopy: Combining highly selective spectral excitation In vivo with 21 T detection generates SNR ratios of >50:1 in <6 sec with virtually complete suppression of water Novel spectral fingerprints for stroke in the spectral region downfield of water which contains numerous crucial resonances, but whose direct observation in disease has not been achieved insofar. N Shemesh, JT Rosenberg, JA Muniz, SC Grant, L Frydman, Relaxation Enhanced in-vivo Magnetic Resonance Spectroscopy at Ultrahigh Fields, in Nature Commun.

32 Progress towards HTS Magnets

33 500 MHz Lysozyme Spectra A driven magnet LTS Magnet Maeda et al (2010) IEEE 20: LTS/HTS Driven Magnet Using a Bi2223 coil

34 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 mm Hashi et al., JMR 2015

35 1.3 GHz HTS/LTS Magnet Design 500 MHz LTS 800 MHz HTS (GdBCO a tape conductor) Note the small size of the HTS coil - High current carrying capability The GdBCO tape will be would as a pancake not as a coil Shaking Coil novel concept for damping the long term drift Note the need for low order shims in the interior of the magnet most LTS magnets have these on the outside but this will not be possible with HTS coils. Iwasa s efforts for NMR have been supported by NIH for many years mm Iwasa et al., IEEE Trans Appl Supercond, 2015

36 NHMFL s NIH-supported pilot project for a 24 T, 1ppm, 100 µl magnet Platypus Utilizing a the outer coils of a high field Oxford Magnet (17.5 T) For the HTS conductor a Bi2212 wire conductor the only HTS wire conductor available. B Wire conductor s have the advantage that the current is constrained to a nearly linear path and they can be wound in a coil. - this leads to a much more stable magnet - it also leads to a more homogeneous and reproducible field. S-2 S-3 S-4 T-1 T-2 HTS-NMR Prototype 23.5 T: 17.5 T LTS T HTS mm

37 NHMFL s 30T mammal : Proposals (D. Markiewicz & H. Weijers) HTS section shares many design parameters with 32 T design Field homogeneity and stability are the major new challenges Bio-NMR

38 Science and Technology at High Fields: 36 T Series Connected Hybrid Magnet for NMR & MRI Bruker AVANCE III HD TM High Performance Ultra High Frequency Digital NMR Console A Collaboration with Bruker on Field Regulation and Stabilization; 17 O NMR spectroscopy Three 1 H Frequencies between 23 and 36 T for frequency dependence studies. Triple Resonance Gradients for micro imaging an option Unique series connection for the 12T superconducting outer magnet with the 24 T resistive insert designed for enhanced homogeneity A Prelude to HTS Magnets with fields of 30, 40, 50??T

39 Scientific Plan VISION: A Interdisciplinary Program that takes Unique Advantage of the: Enhanced Homogeneity Increased Run-Time compared to the Resistive Magnets High Field Strength Improved Temporal Stability Enhanced Experimental Flexibility PROBES: SCH SPECIFICATIONS Low g MAS Probe 1 ppm temporal stability 2.0 mm CP MAS HCN Probe 1 ppm homogeneity Static 1 H-X Probe 15 hour run time 1.6 mm CP MAS Probe 14 MWatts Micro-Imaging Probe 40 mm bore Probes set up with Internal & External Locks

40 The Superconducting Outsert is Complete, Tested and in its Cryostat Version #1 of this Magnet is now operational at 36 Tesla in Berlin (not for NMR).

41 An Exciting and Very Challenging Future for Solid State NMR lies ahead with HTS Magnets