Broadband excitation in nuclear magnetic resonance
Theoretical methods for designing sequences of radio frequency (rf) radiation pulses for broadband excitation of spin systems in nuclear magnetic resonance (NMR) are described. The sequences excite spins uniformly over large ranges of resonant frequencies arising from static magnetic field inhomogeneity, chemical shift differences, or spin coupling, or over ranges of rf field amplitudes. Specific sequences for creating a population inversion or transverse magnetization are derived and demonstrated experimentally in liquid and solid state NMR. One approach to broadband excitation is based on principles of coherent averaging theory. A general formalism for deriving pulse sequences is given, along with computational methods for specific cases. This approach leads to sequences that produce strictly constant transformations of a spin system. The importance of this feature in NMR applications is discussed. A second approach to broadband excitation makes use of iterative schemes, i.e., sets of operations that are applied repetitively to a given initial pulse sequences, generating a series of increasingly complex sequences with increasingly desirable properties. A general mathematical framework for analyzing iterative schemes is developed. 115 references.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6433271
- Report Number(s):
- LBL-18475; ON: DE85003522
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
NMR SPECTROMETERS
RF SYSTEMS
NUCLEAR MAGNETIC RESONANCE
EXCITATION
ITERATIVE METHODS
POPULATION INVERSION
SPIN
ANGULAR MOMENTUM
ENERGY-LEVEL TRANSITIONS
MAGNETIC RESONANCE
MEASURING INSTRUMENTS
PARTICLE PROPERTIES
RESONANCE
SPECTROMETERS
651100* - Nuclear Physics- Experimental Techniques- (1980-)
440300 - Miscellaneous Instruments- (-1989)