Electropermanent magnets for variable-field NMR

Chad Ropp; Cheng Chen; Mason Greer; Jarred Glickstein; Lamar Mair; Olivia Hale; David Ariando; Sahar Jafari; Anjana Hevaganinge; Soumyajit Mandal; Irving N Weinberg

doi:10.1016/j.jmr.2019.04.010

Electropermanent magnets for variable-field NMR

J Magn Reson. 2019 Jun:303:82-90. doi: 10.1016/j.jmr.2019.04.010. Epub 2019 Apr 24.

Authors

Affiliations

¹ Weinberg Medical Physics, 12156 Parklawn Dr, Rockville, MD 20852, USA.
² Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA. Electronic address: cxc717@case.edu.
³ Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA.
⁴ Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA. Electronic address: sxm833@case.edu.

PMID: 31026669
DOI: 10.1016/j.jmr.2019.04.010

Abstract

In this work, a dynamically tunable B₀ field is used to perform variable-field NMR. The system consists of an array of electropermanent AlNiCo-5 magnets whose magnetizations are individually programmed using pulse-power control. This design allows the field strength to be varied for field-dispersion measurements. An ultra-broadband front-end is utilized that maintains efficient power transmission over a broad range of frequencies for robust operation without probe tuning. We perform T₁-T₂ correlation measurements at various B₀ field strengths (0.5-2 MHz) and demonstrate discrimination of different dairy products. We observe variation in the frequency dependence of the proton spin-lattice relaxation for the different products as a function of the degree of protein hydration. This variable-field technique provides a low-cost alternative to fast field-cycling NMR and could open possibilities for novel contrast measurements and spatial encoding in magnetic resonance imaging.

Keywords: dispersion; Broadband; Electropermanent magnet; Variable field NMR.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.