DEVELOPMENT OF A HIGH RESOLUTION NMR SCATTERING SYSTEM

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NMR scattering based on spin coherence transport mediated through dipolar interactions is a new field that we are developing. To make a meaningful measurement a magnetization grating must be created across the sample with a pitch comparable to the interspin distance of a dipolarly coupled spin pair. This demands gradient fields in excess of i04 G/cm. We have developed a means of creating pulsed gradients that can be finely controlled and which will deliver a magnetic field gradient of 100,000 G/cm at 1,000 A. We have also developed a robust switching circuit that delivers controllable current pulses at these levels. Important characteristics are fast switching times, repeatability and the stability of the gradient system in a strong background field. Over the past year we have rebuilt the spectrometer to improve the resolution of the pulse programmer and the spectral purity. Also the probe has been rebuilt to include a gomometer.