An open source tool for design and construction of Halbach array based low field magnets, passive shims and a robotic field mapper: MRI4ALL

Motivation: A comprehensive open-source toolbox for both design and development of low-field MRI magnets, passive shims and a robotic field mapper can accelerate democratization of low field MRIs. Goal(s): Develop an open-source tool for optimization and construction of Halbach array magnets and passive shims. Additionally, develop and build open-source field mapper. Approach: A simple python-based workflow was used for magnet and passive shim design, and an automated CAD model export and ring former development for the optimized geometry. Results: A 43mT Halbach array was developed with our approach in a week at the MRI4ALL Hackathon. Compact passive shims improved homogeneity in simulation and measurements. Impact: We have built an easy-to-use open source framework for magnet and passive shim design for low-field MRI with a capability to extract a CAD-file for easy building. Additionally an open source field mapper is developed and is used for validation.