"The construction and performance of a system to generate pulsed magnetic field gradients for use with a commercial superconducting NMR spectrometer for the purpose of molecular self-diffusion measurements is described. Types of coils that provide linear field gradients are discussed. The design and construction of a conventional Helmholtz pair is outlined. A procedure to estimate the magnitude of the field gradients generated by the Helmholtz coils is explained. The design of a circuit to generate fast current pulses using a power MOSFET has been detailed and compared with a functionally similar circuit using bipolar power transistors. The performance of the design has been evaluated and discussed.
A 15-turn Helmholtz pair with a separation distance of 16 mm constructed on a 12 mm glass form was used for the self-diffusion experiments. 28 gauge enameled copper wire (diameter = 0.3211 mm) was used for the coils. Magnetic field-gradients of the order of 8 G/cm/A were experimentally determined. The current pulse generator produced current pulses up to a maximum amplitude of 17.5 A with the worst case rise and fall times of 40 μs and 24 μs respectively"--Abstract, page ii.
Dawson, Darrow Finch, 1931-2007
Wilson, Edward A.
Blum, Frank D.
Ho, C. Y. (Chung You), 1933-1988
Electrical and Computer Engineering
M.S. in Electrical Engineering
University of Missouri--Rolla
vii, 62 pages
© 1989 Saumil Shirish Mehta, All rights reserved.
Thesis - Open Access
Print OCLC #
Link to Catalog Record
Mehta, Saumil Shirish, "A pulsed field-gradient system for nuclear magnetic resonance diffusion experiments" (1989). Masters Theses. 840.