Designs for a 50 cm long 27 cm clear bore Halbach array of 12 x 12 x 12 mm permanent magnets to create a homogeneous field suitable for neurological MRI


Thomas O’Reilly¹, Wouter Teeuwisse¹, Andrew Webb¹

Estimated cost

10 000€ (includes machining costs)


Stable release

This project describes the construction of a 27 cm diameter, 50 cm long homogeneous Halbach array magnet. It consists of 23 rings, each with two layers of 12x12x12 permanent magnets. Design files are provided for those wanting to laser cut, CNC mill, or water-jet cut the positions of the magnets. For different-sized magnets, a genetic algorithm for homogeneity optimization is available (which can also be used for additional shimming), as is a programme for gradient coil design.



1C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands