Abstract

Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) using the higher polarization of electron radical spins compared to nuclear spins. The addition of electron radicals for DNP to the sample can cause hyperfine broadening, which decreases the resolution of the NMR resonances due to hyperfine interactions between electron and nuclear spins. Electron decoupling has been shown to attenuate the effects of hyperfine coupling in rotating solids. Magic angle spinning (MAS) DNP with electron decoupling requires a high electron Rabi frequency provided by a high-power microwave source such as a frequency-agile gyrotron. This dissertation describes the development of instrumentation to improve electron decoupling through a higher electron Rabi frequency, including two designs for frequency agile gyrotrons and a MAS rotor resonator to increase the effect of microwaves at the sample. Electron spin relaxation times are increased at cryogenic temperatures, enabling manipulation of electron spins with lower electron Rabi frequency. Therefore, a cryostat with interchangeable MAS-DNP NMR probes for DNP experiments ranging from 4-80 K has been constructed and tested.

Committee Chair

Alexander B. Barnes

Committee Members

Joseph Ackerman, Sophia Hayes, Richard Loomis, Jacob Schaefer,

Comments

Permanent URL: 2019-03-04

Degree

Doctor of Philosophy (PhD)

Author's Department

Chemistry

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

Summer 8-15-2018

Language

English (en)

Author's ORCID

https://orcid.org/0000-0003-3903-8842

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