Broadband excitation in magnetic resonance by self-refocusing doubly frequency-modulated pulses
✍ Scribed by Vladimir L. Ermakov; Geoffrey Bodenhausen
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 543 KB
- Volume
- 204
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
It is shown how transverse magnetization can be excited with a single low-power radio-frequency pulse consisting of a superposition of two frequency-modulated components. The phase dispersion obtained with this self-refocusing pulse is very small over bandwidths that are far greater than the amplitude of the radio-frequency field. The new pulse shape may be derived from spinecho sequences employing frequency-modulated "chirp" pulses by shifting the excitation and refocusing pulses in time so that they are partly or completely superimposed. The duration of chirp spin-echo sequences can be reduced by a factor two by this contraction process, so that the echoes are less sensitive to transverse relaxation.