Design, Fabrication and Measurement of a 3 T Cryogen-Free Animal MRI Superconducting Magnet

As an essential system component of a magnetic resonance imaging (MRI) instrument, the magnet offers strong and uniform magnetic field intensity, which is critical for achieving the desired image resolution. This work presents the design, fabrication, and measurement of a 3 T cryogen-free superconducting magnet for animal MRI applications. The magnet presented excellent stability, maintaining a field variation of just 0.01 ppm per hour at full strength. After passive shimming, the magnetic field homogeneity achieved around 32 ppm over an imaging sphere with a diameter of 160 mm. The success of this reliable magnet technology paves the way for its adoption in future whole-body human MRI systems.