Electromagnets for fast-switching of the magnetic field: air core versus iron yoke. A comparative study.

M. DELFINA VÉLEZ IBARRA; GABRIELA PERETTI; EDUARDO ABEL ROMERO; ESTEBAN ANOARDO

Conferencia; 9th Conference on Fast Field-Cycling NMR Relaxometry; 2015

Air core electromagnets (EM) weresuccessfully used for the fast switching of the magnetic field in field-cyclingNMR apparatus1-6. This choice can be contrasted with the use of ironyoke or ferromagnetic core magnets aimed for similar purposes6-8. Typicaltechnical requirements for EM are high field-to-power ratio (Fabry-factor), adequateelectric performance for fast-switching of the field and NMR-compatible field homogeneitywithin the sample volume. However, there are other aspects that may beevaluated like the physical limits for the maximum reachable field, thecomplexity of the power network architecture, the demands on the controlsystem, the energetic efficiency, cooling efficiency, volume & weight,cost, etc. We will analyse the pros and cons of each approach fromthe physical and electronic points of view. [1]- K-H. Schweikert; R. Krieg ; F. Noack.  J. Magn. Reson. 1988, 78, 77-96.[2]- E. Anoardo; G. Galli; G. Ferrante.  Appl. Magn. Reson. 2001,20, 365- 404.[3]- O. Lips; A. Privalov ; S. Dvinskikh; F. Fujara. J. Magn. Reson. 2001,149, 22-28.[4]- R. Kimmich; E. Anoardo. Progr. NMR Spectrosc. 2004,44, 257?320.[5]- G. Ferrante; S. Sykora. Adv. Inorg. Chem. 2005,57, 405-470.[6]- F. Fujara; D. Kruk; A. F. Privalov. Prog. NMR Spectrosc. 2014, 82,39-69.[7]- D. Plendl; M. Fujara; A. F. Privalov; F. Fujara. J. Magn. Reson. 2009, 198, 183-187.[8]- D. M. Sousa; G. D. Marques; J. M. Cascais; P. J. Sebastião. SolidState NMR 2010,38, 36-43.