MRI: Development of an Innovative EPR Spectrometer

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With this award from the Major Research Instrumentation Program, Professor Sandra Eaton from University of Denver and colleague Gareth Eaton will develop an innovative digital electron paramagnetic resonance (EPR) spectrometer that can operate at any frequency up to 9 to 10 GHz using an AWG (arbitrary waveform generator) source and digital detection. A single digital spectrometer will be capable of performing a wide range of pulse, rapid-scan, and continuous-excitation EPR experiments at variable frequencies, instead of requiring multiple instruments for different frequencies as is currently the case. Users will be able to implement new experiments in user-friendly software without requiring costly new hardware. Digital detection improves signal-to-noise and decreases data acquisition time. Individual resonators (probeheads) will be narrow-banded to maximize sensitivity. The spectrometer will have a series of readily interchangeable resonator modules for experiments at frequencies that are currently widely used (such as 9.5 GHz) and ones (such as 4 GHz) where spectrometers are not currently available, but which theory predicts will be very valuable. The proposal is aimed at enhancing research training and education at all levels. Projects include the frequency dependence of nitroxyl electron spin relaxation, spin trapping of the reactive oxygen species superoxide, and characterization of defect centers in diamonds with potential applications in quantum computing. EPR is the method of choice for studying molecules with unpaired electrons. Applications range from organic radicals and transition metal complexes, to materials for nanotechnology and solar energy conversion, characterization of metal sites in proteins, and measurement of long distances in polymers, proteins, and nucleic acids. The much greater flexibility of a digital EPR spectrometer will make it more useful in a wider range of applications. The detailed design of the new digital EPR spectrometer will be published to make it available to other research laboratories and to commercial vendors, which will open up new vistas for EPR spectroscopy. In addition, the project will contribute to workforce development by providing a cutting-edge interdisciplinary learning environment. Students will have the opportunity to interact with engineers, physicists, and chemists. Furthermore, students from nearby Regis University, with a high proportion of first-generation college students, will use the EPR laboratory on a regular basis.