High-resolution high-frequency dynamic nuclear polarization for biomolecular solid state NMR

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, June 2011.Vita. Cataloged from PDF version of thesis.Includes bibliographical references.Dynamic Nuclear Polarization (DNP) has exploded in popularity over the last few years, finally realizing its potential to overcome the detrimental lack of sensitivity that has plagued performing NMR experiments. Applied to magic angle spinning (MAS) experiments, this renaissance of DNP has been primarily driven by the development of instrumentation; namely gyrotron oscillators as high-power stable microwave power sources and the NMR probes and associated equipment required to spin samples routinely below 100 Kelvin. The first three chapters of this thesis provide an overview of the theory, instrumentation, and applications of DNP. Chapter 1 introduces the magnetic resonance Hamiltonian with a focus on interactions that are necessary to control in order to obtain high-resolution DNP spectra. Chapters 2 and 3 are published reviews of DNP. Whereas Chapter 2 targets magnetic resonance spectroscopists, Chapter 3 is intended for an electric engineering audience. Both reviews are included as the associated depth and coverage of the topics are complementary and lead to a better understanding of DNP. The later chapters describe in detail advancements in probe, cryogenics, and gyrotron technology required to perform DNP MAS experiments, as well as the gains in sensitivity and resolution such instrumentation has permitted. Of particular importance is the development of a cryogenic sample ejection system that resulted in exquisite resolution of spectra recorded 10 W across the band, which results in substantially improved DNP performance.by Alexander B. Barnes.Ph.D