NMR Instrumentation
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A course on Nuclear Magnetic Resonance instrumentation
according to its various Applications, inclusive of historic notes.
If you are interested in this course/talk, please, contact us.

Relator: S.Sykora.   Duration: 15-30 hours.

  • 1. The beginnings
    • C.J.Görter, F.Bloch, M.E.Packard,... and their instruments
  • 2. What does one need to build an NMR instrument
    • Magnet, probehead, RF transmitter, RF receiver, ...
  • 3. Excitation/Detection methods (E/D)
    • Simultaneous E/D: continuous wave (CW) methods based on:
      • Susceptivity variations (Q-meters, marginal oscillators)
      • Absorption/dispersion: bridges or crossed coils
    • Separate E/D: pulsed methods
    • Other methods:
      • Pseudo-CW (SSP), stochastic, Hadamard, correlation NMR, ...
  • 4. Principal NMR applications
    • High chemical resolution
      • Analysis of chemical structure
      • Stereochemical studies
      • Molecular dynamics studies
    • Low chemical resolution in vitro
      • Analysis of materials (polymers,porous media,tissues,...)
      • Studies of molecular dynamics and aggregation states
    • Low chemical resolution in vivo
      • MR imaging
      • MR angiography
      • Flow imaging
      • Functional MR imaging
    • Hybrid applications
      • TMR with surface coils
      • Spectroscopic imaging
    • Geophysical applications
      • Well-logging
      • Geo-imaging and prospecting
      • Earth-field NMR magnetometers
    • Industrial applications
      • Quality assessment
      • Process control
  • 5. Generation of magnetic field
    • Permanent magnets
      • Components: yoke, poles, pole expansions, ...
      • Materials: alnico, ferrites, rare earths, ...
      • Auxiliary devices: thermostat, modulation coils, ...
    • Electromagnets
      • More components: energization coils, power supply, cooling system, ...
      • Materials: low-hysteresis ferromagnetic alloys, ...
      • Auxiliary devices: modulation coils, ...
    • Low-temperature superconductors
      • Components: main coil, cryo-switches, cryo-shims, ...
      • Materials, including perspectives of high-temperature superconductors
      • Cryogenic subsystem: dewars, transfer lines, liquid gases
      • Quantum effects: once-only energization
    • Air coils
      • Merits: no saturation limits, possibility to cover large volumes
      • Demerits: large power consumption
    • Systems capable of fast variations of the field value
      • Mechanical shuffling of the sample between two magnets
      • FFC (fast field-cycling) and its technical pecularities
    • Other sources of usable fields
      • Internal fields of ferromagnetic materials
      • Earth field
      • Zero field (NQR)
    • Comparative merits of various technologies
  • 6. Magnetic field conditioning
    • Stabilization
      • flux stabilizers, Hall probes, NMR 'lock'
    • Improving field homogeneity
      • mechanical and electrical 'shims', sample rotation
    • Generation of field gradients
    • Relative merits and application areas of the various devices
  • 7. Generation of radiofrequencies
    • Basic characteristics of a radiofrequency field
      • frequency, phase, amplitude
    • Trasmission of radiofrequencies
      • coaxial cables and their characteristics, matching
    • Modulation of radiofrequencies
      • CW, pulses, gating, profiled pulses
    • Use of multiple RF channels
      • Lock channel (f0), Observe channel (f1), Decoupler channel (f2), ...
    • Power RF amplifiers and their characteristics
  • 8. The 'probe' (head, probehead, front-end, ...)
    • Rewiev of solutions according to various applications:
      • what is common and what changes
    • Principal RF characteristics of a probe
      • type of coil, bandwidth, Q-factor, tuning range, ...
    • Accessories of a probe
      • Sample temperature control system (VT)
      • Field gradient coils/ Homospoil coils
      • External NMR lock sub-system
      • Coil/s for multiple resonances (such as decoupling)
      • Other (MAS, He evaporator, high pressure, cooled coils, ...)
  • 9. Detection of radiofrequencies
    • Preamplifiers
      • general characteristics and constraints imposed by NMR
    • Diode detectors
      • linearization, envelope detectors, power detectors
    • Phase detector (lock-in)
    • Use of interfrequencies: when and why
    • Dual-channel, quadrature detection
    • Digital detection
  • 10. NMR instrument control
    • Fast events-sequence generator (pulser)
    • 'Slow' interfaces and system busses
  • 11. Handling of low-frequency signals
    • Filters (anti-aliasing, analog, digital)
    • Obsolete acquisition methods (historic perspective):
      • Visual acquisition from a long-persistance scope
      • Fotographic acquisition from a normal scope
      • Digital scopes with memory
      • Sample-and-Hold and Box-Car-Integrator devices
      • Electromechanic recorders
    • Modern A/D conversion and digital acquisition
      • requirements and characteristics
    • Accumulation and averaging of digital data
      • The concept and its merits
      • Dangers: overflow, aliasing, anomalous noise effects
      • Phase cycling, pipe-lined pre-traetment, ...
      • Dedicated systems versus generic computers
  • 12. Evaluation of NMR data
    • Types of evaluation:
      • Archivation
      • Filtering, window convolutions, integration, ...
      • Artifacts suppression (mention methods such as MEM, LP, ...)
      • FFT (spectroscopy, imaging) and its revolutionary contribution to HR-NMR
      • Image reconstruction from k-space data (imaging)
      • Types of evaluation reqested by different Applications
    • Required characteristics of the employed data systems

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