Magnet technology Insights & recent UHF results

Transcription

1 Magnet technology Insights & recent UHF results Daniel Baumann, Rainer Kümmerle Bruker Biospin AG Switzerland 25. November 2016 Brussels Innovation with Integrity Innovation with Integrity

2 1 GHz Aeon at NZN Bayreuth

3 Niob-Titanium Wire Production Cold extrusion from 1 m length to m

4 NbTi and Nb 3 Sn wire samples at intermediate drawing stage NbTi, 36 Filaments Nb 3 Sn, 40,000 Filaments NbTi, Filaments 4

5 (NbTaTi) 3 Sn wire with ~ filaments 199 filament bundles 199 filaments in each bundle 5

6 Low Temperature Superconductors (LTS) NbTi: Critical temperature TC : 9.6 K Highest magnetic field: ~11 T (useful up to fields of ~400 MHz) Nb3Sn: Critical temperature TC : 18 K Highest magnetic field: ~23 26 T (useful up to fields of ~1 GHz)

7 Nb3Sn production and processing: Cold extrusion

8 Low Temperature Superconductors (LTS) Niobum-Bronze wire, easy to bend/wind Niobum-Bronze wire with glass fibre insulation Reacted (heat-treated) Nb 3 Sn wire, brittle like ceramics 1.2 x 1.8 mm ~ filaments

9 Nb3Sn production and processing: Winding and reaction process Copper (heatload, quench protection) Bronze; Cu with up to 16% Sn and 0.3 % Titanium Niobium Tantal Glass fiber insulation

10 Nb3Sn production and processing: Winding and reaction process Desizing: Glassfibre mesh insulation is pulled over the wire, potato starch is used to lubricate. Before heat treatment the starch needs to be removed. This is achieved by repeated heating and vacuum pumping.

11 Nb3Sn production and processing: Winding and heat treatment process The wound Nb 3 Sn coils are heat treated in a ca. 2 weeks process The process takes place in a high vacuum oven which transfers heat via internal radiation plates to the wound coils Depending on the wire manufacturer, the wire diameter and the shape of the wire the heat treatment process needs to be adapted

12 Mechanical forces on wires Copper Bronze Niobium (Tensile strength: 125 MPa) Tantalum (Tensile strength: MPa) The different materials within the wire need to have very similar expansion coefficients (from RT up to ~700 C and later from RT down to -269 C) Requires extremly robust coil former The coil former design is optimized to neither produce additional forces on wire nor to allow for empty space

13 Mechanical forces on wire In a charged superconducting coil forces point in different directions depending on position: Radial Force Diameter-dependent pressure/stress (hoop-stress, up to 200 MPa) Axial Force transverse stress on wire 200 MPa = 2000 bar or ~1973 atm (20400 m water column) For comparison: 30 atm or 300 m is a typical lower dive level for larger submarines

14 J c,overall (A/mm 2 ) Wire Technology: Bronze wire with high Sn content Cu-16%Sn-Ti Bronze 1.83x1.22 mm Filaments f Filaments = 4.8 mm T = 4.2K T = 4.2K 16%Sn 16%Sn 14%Sn T = 2.2K Proton Resonance Frequency (MHz) (NbTaTi) 3 Sn (NbTaTi) 3 Sn with high Sn content (NbTaTi) 3 Sn with high Sn content T=2.2K 21T 1 GHz m 0 H (Tesla) Increased Sn content Higher Critical Current J c

15 Critical Surface Current density j c T=const. B=const. 12T 4.2 K Magnetic field B max. j c (4.2K, 12T) Temperature T 15

16 Key Bruker UHF Magnet Technologies Field coil Shielding coil 2K cooling Active shielding (3 rd generation) Advanced LTS Superconductors External Disturbance Suppression (EDS ) B o Active refrigeration Aeon technology UHF Coil technology

17 Key UHF Technologies: High current designs and rectangular wire High current design I M = 2 I o Low current design I M = I o + Bo + Bo rectangular wire conductor area = 4 mm² round wire conductor area = 2 mm²

18 Advantages of Rectangular UHF LTS Higher current results in larger wire cross sections Better winding chamber filling factor Less insulation material in winding chamber Better control of forces Enables highest fields Enables smaller magnets 2 mm Cu Nb 1 mm (NbTaTi) 3 Sn-conductor (NbTaTi) 3 Sn Bundle NbTi-conductor

19 UltraStabilized 2 Kelvin Sub-cooling: used today for 850 MHz to 1.2 GHz Long term stable magnet Highest field strengths Increased magnet stability Higher safety margins Lowest drift rates Easy helium refills Compatible with new Aeon & HTS technologies Patented technology Pioneered by Bruker Proven track record Over 230 systems installed Thermal Barrier Joule-Thompson Cooling Unit Superconducting Magnet Coil UltraStabilized technology delivering unique performance, stability and safety

20 Aeon Active-Refrigeration: no compromise on High-Resolution NMR Performance He-Re-Liquefaction for 2K sub-cooled magnets J-T Unit PTC 4.2K 2K Subcooled helium gas Sub-cooled LHe bath at same pressure of 1.05 bar as the 4.2K bath Low pressure (below 30 mbar) limited to the JT cooling unit maintained by pumping P low P high He gas return line He compressor Subcooling Pump in BMPC II unit He gas exhaust He gas exhausted from the pump at room temperature and fed back to a PTC Recovered He gas re-liquefied by the PTC Thermal shield cooled by the 1 st stage of the PTC (N2 free, no nitrogen vessel) No Cryogen consumption during normal operation

21 Bruker UHF Magnet Milestones 1992 First 750 MHz magnet 1995 First 800 MHz NMR magnet 1998 First 750 MHz wide bore magnet 2001 First 800 MHz actively shielded magnet 2004 First 850 MHz WB shielded magnet 2004 First 900 MHz actively shielded magnet 2006 First 800 MHz single-story shielded magnet 2006 First 950 MHz actively shielded magnet 2009 First 900 MHz WB shielded magnet 2009 First 850 MHz single-story shielded magnet 2009 First 1000 MHz magnet (unshielded) 2012 First Single-Story Aeon 800 MHz WB 2013 First Single-Story Aeon

22 Bruker UHF Magnets Today- the state of the art: - Actively shielded (3rd generation) - Aeon closed loop cooling (LN2-free, no LHe boil-off) - Persistent, homogeneous, ultra-stabilized Aeon mm single-story NMR magnet Aeon 21 T 11cm FTMS/MRI Magnet Aeon 1 GHz 54mm NMR Magnet

23 950 MHz 5mm TCI: Water Suppression 2mM Sucrose in H 2 O:D 2 O 90:10 Resolution: 11% Hump: 8.3 / 29.8 Hz ppm ppm

24 TCI 950 MHz 15 N detection 15 N detected refocused INEPT C/N-labeled ubiquitin Adiabatic 13 C (Chirp, 48 khz sweep) CPD decoupling. NS = 32, expt. Time 60 seconds ppm

25 TCI 950 MHz Protein Data C/N-labeled ubiquitin ppm 1 H- 15 N sofast-hmqc NS = 2 TD = 1k x 128 Expt. Time 18 seconds Vertical projection: 15 N detected INEPT Horizontal projection: C & N decoupled excitation sculpting ppm

26 TCI 950 MHz Protein Data ppm C/N-labeled ubiquitin 10 3D (H)CCH-TOCSY 2D CH plane 20 NS = 4 30 TD = 3k x 256 Mixing = 12.5 khz 40 Expt. Time 20 minutes ppm 26

27 TCI 950 MHz Protein Data: 15 N detection C/N-labeled ubiquitin 15 N detected 3D CBCACON ppm d(co) 172 NS = 16 TD = 2k x 64 x 80 D1 = 1s Expt. Time: 30 hours 3D and NCO / NCC projections shown ppm ppm d(c) d(n) ppm d(n)

28 TCI 950 MHz Protein Data: 15 N detection C/N-labeled ubiquitin 15 N detected 3D (h)cccon ppm d(co) 172 NS = 16 TD = 2k x 64 x 96 D1 = 1s Expt. Time: 37 hours 3D and NCO / NCC projections shown ppm ppm d(n) d(c) ppm d(n)

29 ENC 2016 Announcement: World's first shielded Aeon 1 GHz System installed Active shielding reduces space requirements by > one order of magnitude Aeon 1 GHz magnets leverage advanced BEST superconductors Active refrigeration eliminates LN2, reduces LHe boil-off essentially to zero New GHz-class magnet, novel Cryoprobes, 111 khz MAS probes, and new NMR methods expand frontiers in structural biology, membrane protein and intrinsically disordered protein (IDP) research Aeon 1 GHz at Research Center for Bio-Macromolecules at University of Bayreuth Innovation with Integrity

30 1 GHz 5mm TCI: Water Suppression 2mM Sucrose in H 2 O:D 2 O 9:1 Resolution: 10% Hump: 9.7 / 16.7 Hz Composite pulse & crusher gradient presat ppm ppm

31 1 GHz 5mm TCI: 13 C RF power handling 2mM Sucrose in H 2 O:D 2 O 9:1 1 H- 13 C HSQC ppm NS 2 TD 8k x 256 AQ 400ms Adiabatic CPD decoupling ppm

32 1 GHz 5mm TCI: 13 C RF power handling 2mM Sucrose in H 2 O:D 2 O 90:10 1 H- 13 C HSQC AQ 400ms Adiabatic CPD decoupling 2D HSQC 1 H projection 1D 1 H spectrum

33 1 GHz 5mm TCI: CC-TOCSY C/N-labeled ubiquitin 13C ppm detected CC-TOCSY 10 NS = TD = 4k x 128 Mixing = 13.5 khz 30 Expt. Time 40 minutes ppm 33

34 1 GHz relaxation-optimized 3D C/N-labeled ubiquitin 3D BEST-HNCO NS = 2 TD = 1k x 48 x 96 D1 = 100ms Expt. Time 40 minutes

35 1 GHz relaxation-optimized 3D C/N-labeled ubiquitin 3D BEST-HNCO NS = 2 TD = 1k x 48 x 96 D1 = 100ms NUS 12.5% Expt. Time: 5 minutes! (traditional sampling: 40 minutes) CS processing

36 1 GHz relaxation-optimized 3D C/N-labeled ubiquitin 3D BEST-TROSY-HNCOCACB NS = 2 TD = 1k x 64 x 256 D1 = 200ms Expt. Time: 3 hours 46 minutes

37 1 GHz relaxation-optimized 3D C/N-labeled ubiquitin 3D BEST-TROSY-HNCOCACB NS = 2 TD = 1k x 64 x 256 D1 = 200ms NUS: 12.5 % CS processing Expt. Time: 28 minutes (traditional sampling: 3.75 hours)

38 Acknowledgements Daniel Baumann Gerhard Roth Patrick Wikus Ruedi Gaisser

39 Copyright 2011 Bruker Corporation. All rights reserved. Innovation with Integrity