Construction, Design, and Evaluation of RF Probes

Next offering: In-person meetings were cancelled throughout 2020-2021 due to the pandemic; next possible offering is October 2025 (3-4 days)

Location: NHMFL (MagLab), Tallahassee, Florida
Leaders: Bill Brey, Joanna Long, Jason Kitchen, Wenping Mao, Malathy Elumalai, and Peter Gor’kov.
Last offering: May 23-25, 2022 (please e-mail Jason Kitchen at kitchen@magnet.fsu.edu if you would like to be added to a list for notification of future workshops).

This workshop will have introductory elements of the physics and electrical engineering approaches to RF manipulation and detection. These will be coupled with hands on work using CAD, 3D printing, and state of the art approaches to the construction of NMR probes as well as practical evaluation of NMR probe performance. Participants will also be introduced to various software packages developed for mechanical and electrical engineering applications and how they can be used in NMR probe projects as well as project management tools for tracking and documenting NMR probe projects.

Goals:

  • Learn best practices for NMR coil and circuit designs
  • Develop a working knowledge of NMR probe construction and testing
  • Appreciate the various factors affecting sensitivity, B1 homogeneity, and resolution at RF frequencies typically used in high field NMR systems

Sample schedule:

Day 1: Welcome! – arrival, registration/setup, enhanced safety training for work in an RF lab, and reception

Day 1: Introduction to RF circuitry and NHMFL magnets and probes

  • Lectures on LC circuits, Impedance matching, Maximum power transfer, basics of coil geometry for NMR and MRI applications, evaluating individual RF channel efficiencies and isolation, and 3D/CAD design software
  • Practicum on soldering circuits, analysis of cable trap and balun design, coil tuning, demonstration of RF transmission and isolation using network analyzer.

Day 2: Specialized designs and building NMR probes

  • Lectures reviewing NMR probe circuits for multi-resonant coils, phased array coils, parallel-transmit and par­allel-receive coil, current design strategies for high-resolution NMR probes, ssNMR probes, and MRS/I coils for in vivo applications.
  • Practicum on bench testing of efficiency, homogeneity and isolation, NMR testing of probe RF perfor­mance, resolution and sensitivity of solution NMR probes, power handling and B1 homogeneity for ssNMR probes.

Day 3: Advanced RF topics and evaluation

  • Lectures on magic angle spinning, cryogen­ics, magnetic susceptibility, power handling, approaches for en­hancing signal sensitivity and mitigat­ing noise, filtering, isolating and amplification of RF signals;
  • Practicum on temperature calibration, magic angle spinning, shimming and line shape measurements for solution NMR and ssNMR; basics of a modern NMR console