A Method for DeterminingB1Field Inhomogeneity. Are the Biases Assumed in Heteronuclear Relaxation Experiments Usually Underestimated?
✍ Scribed by Marc Guenneugues; Patrick Berthault; Hervé Desvaux
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 209 KB
- Volume
- 136
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
We describe a method allowing the determination of the effective B 1 field amplitude distribution in a high-resolution NMR spectrometer. This method which can be adapted to almost any sequence, essentially consists of a nutation followed by a purging B 0 gradient pulse. Experimental results obtained with this approach are described in homonuclear and heteronuclear cases. The experimental distributions are used to estimate the biases induced by B 1 inhomogeneity, as well as the loss of RF power on heteronuclear transverse self-relaxation rate determination. In this type of measurement, the experimental biases induced on the intensities can be as large as 5% for long mixing times.