Improved broadband inversion performance for NMR in liquids

Citation
Ma. Smith et al., Improved broadband inversion performance for NMR in liquids, J MAGN RES, 151(2), 2001, pp. 269-283
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis","Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF MAGNETIC RESONANCE
ISSN journal
1090-7807 → ACNP
Volume
151
Issue
2
Year of publication
2001
Pages
269 - 283
Database
ISI
SICI code
1090-7807(200108)151:2<269:IBIPFN>2.0.ZU;2-R
Abstract
New NMR broadband inversion pulses that compensate both for resonance offse t and radiofrequency (RF) inhomogeneity are described. The approach describ ed is a straightforward computer optimization of an initial digitized wavef orm generated from either a constant-amplitude frequency sweep or from an e xisting composite inversion pulse. Problems with convergence to local minim a are alleviated by the way the optimization is carried out. For a given du ration and maximum allowable RF field strength B-1 (but not necessarily giv en RMS power deposition), the resultant broadband inversion pulse (BIP) sho ws superior inversion compared to inversion pulses obtained from previous m ethods, including adiabatic inversion pulses. Any existing BIP can be syste matically elaborated to build up longer inversion pulses that perform over larger and larger bandwidths. The resulting pulse need not be adiabatic thr oughout its duration or across the entire operational bandwidth. (C) 2001 A cademic Press.