A typical 400 MHz NMR system with a 4.00 inch room temperature bore will have a homogeneous field region of 0.1 ppm over a 20 mm diameter by 20 mm long volume. The magnetic field drift specification of the magnet is less than 0.01 ppm per hour. All Cryomagnetics NMR magnets have at least 10 ppm homogeneity over the high field region without the use of independent shims. Magnets requiring 1 ppm homogeneity will utilize independent first order superconducting shim coils. This insures field homogeneity specification can be maintained even if the system is installed in an environment having iron or other magnets nearby.
Higher homogeneity is achieved using second order superconducting shim coils.
All NMR magnets are fully tested using state of the art NMR probes and measurement devices at the factory. Customers can be assured of receiving a NMR system that will give quench-free service and meet all specifications. For NMR systems with 1 ppm homogeneity or better, on-site shimming will be necessary. While on-site, the technician will instruct the users on how to operate and maintain the system. This insures that the NMR system you purchase will give years of reliable service.