New insights on fast-field-cycling NMR electromagnets

S. KRUBER, G, FARRHER Y E. ANOARDO

Congreso; Euromar 2015; 2015

Field-cycling NMR instruments aimed for the fast switching of the magnetic field were mainly based on air-cored electromagnets (EM) [1-4].  The general performance of these instruments strongly depends on the EM design and the associated power management & control strategy. Typical technical requirements for this kind of EM are high field-to-power ratio (Fabry-factor), adequate electric performance for fast-switching of the field and NMR-compatible field homogeneity within the sample volume. At first glance, any improvement for EM technology should consider these requirements. However, reducing the thermo-mechanical stress of the magnet assembly, simplifications in the design and robustness are also considerable. We will describe the problem in general and show details on a recent prototype of an α-helical-cut notch?coil geometry with movable pieces having tunable homogeneity and uniformly distributed power dissipation. A more realistic model was used for the optimization process by considering a magnet geometry with broken azimuthal symmetry [5]. This work is the first attempt for an autoadaptive (electronicallycontrolled) magnet system for fast-field-cycling NMR.