NMR shim coil method

摘要

A method for adjusting the desired current values of spherical harmonic shim coils in an NMR magnet utilises a minimal number of measuring points by applying appropriate linear combinations of the corresponding measurement values both with and without a standard current flowing in the corresponding shim coil. The simple, systematic and reliable measurement method does not require any iterative procedure, and the calculated values can serve as starting values for a further shimming procedure. The measuring points may be on the surface of a cylinder (table 3). IMAGE