Nuclear spin waves in spin-polarized hydrogen

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5328156

Johnson, B R

This thesis describes experiments studying nuclear spin transport in spin polarized hydrogen gas at temperatures between 150 mK and 700 mK, and number densities between 1 x 10/sup 15/ cm/sup -3/ and 9 x 10/sup 16/ cm/sup -3/. Pulsed Fourier transform and CW NMR were used for this purpose. The surfaces were coated with /sup 4/He for all the experiments. The observed NMR spectrum showed sharp resonances superimposed on a broader background. The background was attributed to the NMR image of the NMR sample volume. The sharp resonances were attributed to standing spin waves modes in this volume. As recombination of the sample induced a large nuclear polarization, the spin wave resonances became narrower, more numerous, and more intense, as predicted by theory. The magnetic field gradient confined the observed spin wave modes to one side of the sample volume. The ordinary diffusion coefficient D/sub 0/ was measured by observing the recovery of the longitudinal polarization in the NMR sample volume after a large tipping angle pulse due to diffusion of spins from outside the sample volume. By calculating the theoretical spectrum and comparing it with the observed spectrum, the dimensionless parameter ..mu.. was measured. This parameter determines the quality factor Q of the spin wave modes.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 5328156
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
DATA
DIFFUSION
ELEMENTS
EXPERIMENTAL DATA
FOURIER TRANSFORMATION
HYDROGEN
INFORMATION
INTEGRAL TRANSFORMATIONS
MAGNETIC FIELDS
MAGNETIC RESONANCE
NONMETALS
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
RESONANCE
SPECTRA
SPIN WAVES
TRANSFORMATIONS
ULTRALOW TEMPERATURE