Prospects for using neutrons to probe nuclear magnetic resonance signal

The prospect of neutron spectrometers with magnetic fields up to 40 T makes neutron measurement of the nuclear Zeeman splitting feasible. The Zeeman splitting is observed by a neutron spectrometer as an incoherent line with an energy transfer equal to the Zeeman energy. This energy scale is small enough that fields around 15 T are required to sufficiently separate this line from other incoherent processes. Once the Zeeman splitting is observed, a perturbation of the system is required to enable measurement of the nuclear spin relaxation time; the physical quantity measured in a Nuclear Magnetic Resonance experiment. The proposed perturbation is a pulsed field of 10 T. The relaxation of the Zeeman splitting back to the 15 T condition is then recorded as a function of time. The resultant data is the aforementioned measure of the relaxation time. This contribution will describe the requirements for the magnet and neutron spectrometer on a spallation source. These requirements will be illustrated by calculations for an H2O sample. The advantages of using this approach, as compared to decay from complete polarization at low temperatures, will be discussed too