Progress towards 1 ppm at 25 T

The National High Magnetic Field Laboratory (NHMFL) is building a 25 T, 52 mm bore resistive magnet with field uniformity and stability of 1 ppm over a 1 cm diameter spherical volume (DSV). Upon completion the unshimmed magnet's homogeneity was 48 ppm over 1 cm DSV. It has since been ferro-shimmed to 12 ppm over 1 cm DSV and we are in the process of shimming to the 1 ppm level. Details of the design, construction, shimming and stabilizing are presented.