Broadband RF-amplitude-dependent flip angle pulses with linear phase slope

摘要

Pulse sequences in NMR spectroscopy sometimes require the application of pulses with effective flip angles different from 90 degrees and 180 degrees. Previously (Magn. Reson. Chem. 2015, 53, 886-893), offset-compensated broadband excitation pulses with RF-amplitude-dependent effective flip angles (RADFA) were introduced that are applicable in such cases. However, especially RF-amplitude-restricted RADFA pulses turned out to perform not as good as desired in terms of achievable bandwidths. Here, a class of RF-amplitude-restricted RADFA pulses with linear phase slope is introduced that allows excitation over much larger bandwidths with better performance. In this theoretical work, the basic principle of the pulse class is explained, their physical limits explored, and their properties, also compared with other pulse classes, discussed in detail. Copyright (c) 2017 John Wiley & Sons, Ltd.