ABSTRACT

This chapter outlines the exploratory pulsed electron paramagnetic resonance (EPR)-imaging experiments that have been done so far and explains some of the limitations. The relative relaxation rates of nuclear and electron spins limit application of some of the nuclear magnetic resonance (NMR) techniques in EPR. One approach to pulsed EPR imaging that avoids the need for rapid pulsing of the gradients is spin-echo or saturation-recovery detected EPR in the presence of a field gradient. EPR spectra were obtained with different magnetic-field gradients to produce the three-dimensional spectral-spatial-spatial images. Pulsed the magnetic-field gradient on during pulsed-EPR data collection permits a lower field-gradient duty cycle than does the continuous-wave-EPR approach. The magnetic-field gradient pulses used in NMR experiments are very long relative to what will be needed for optimizing the pulsed-EPR imaging experiment. Very low Q structures are needed to achieve excitation of broad EPR spectra.