Low resolution NMR magnets in the 23 to 35 T range at the NHMFL

The National High Magnetic Field Laboratory in Tallahassee, FL, USA has for several years provided low resolution NMR magnets to the condensed matter physics community. There are presently two magnets available, one that provides 24.5 T in a 32 mm bore with inhomogeneity of about 100 ppm over a 10 mm Diameter Spherical Volume (DSV) and another that provides 25 T in 52 mm bore with inhomogeneity of 12 ppm over a 1 cm DSV. The NHMFL is presently constructing the third magnet in this series that should provide field above 29 T with inhomogeneity less than 50 ppm over a 1 cm DSV. The NHMFL is also planning to build a series-connected hybrid to enable low resolution NMR in the 35 T range. History of the existing magnets and design of the 29 T magnet are presented along with analysis and conceptual design of magnets with uniformity in the 1 ppm range and fields in the 35 T range.