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NMR signal averaging in 62T pulsed fields
Benno Meier1, Sebastian Greiser, Jürgen Haase
1University of Leipzig, Faculty of Physics and Earth Science, Linnéstrasse 5, 04103 Leipzig, Germany.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|March 4, 2011
Summary
Researchers precisely measured the time-dependent magnetic field in pulsed Nuclear Magnetic Resonance (NMR) experiments. This technique corrects signal distortions, enabling enhanced signal averaging and precise measurements even for weak signals.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Materials Science
Background:
- Pulsed high magnetic fields offer unique opportunities for Nuclear Magnetic Resonance (NMR) studies.
- The inherent time-dependence of pulsed magnetic fields complicates precise NMR measurements and signal averaging.
Purpose of the Study:
- To precisely characterize the time-dependence of pulsed magnetic fields up to 62T.
- To develop a method for correcting NMR signals affected by field instability.
- To enable high-precision shift measurements and signal averaging in pulsed-field NMR.
Main Methods:
- Nuclear Magnetic Resonance (NMR) experiments conducted in pulsed high magnetic fields (up to 62T).
- Analysis of Free Induction Decays (FIDs) to determine magnetic field time-dependence with high precision (±0.03ppm to ±0.8ppm).
- Development of a demodulation and phase-correction technique based on the characterized field dynamics.
Main Results:
- Accurate determination of the magnetic field's time dependence near its maximum.
- Successful phase-correction and demodulation of FIDs, leading to phase-locked signals.
- Demonstrated significant improvement in signal-to-noise ratio through signal averaging, approaching theoretical expectations.
Conclusions:
- The intrinsic time-dependence of pulsed fields can be effectively removed using the developed method.
- NMR signals can be treated as if acquired under stable static field conditions.
- This technique facilitates precise shift measurements and signal averaging for weak or unknown signals, especially when using a double-resonance probe with a reference signal.
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