Miniaturization design study of a dipole magnet applied to proton therapy beamline

The miniaturization of magnets is crucial for reducing both the physical footprint and the construction cost of a proton therapy facility. The configuration of dipole magnets significantly influences the design of the compact gantry. However, current research demonstrates a degree of subjectivity in achieving an optimal balance between magnet compactness and saturation levels. This study introduces a novel design principle aimed at miniaturizing the yoke of dipole magnets. To be specific, two metrics (i.e. magnet efficiency and magnetization uniformity) are adopted to develop an optimized design that achieves significant weight reduction while maintaining essential magnetic performance characteristics. For the 57-degree dipole magnet discussed in this paper, finite element simulations demonstrate that the optimized design achieves a weight reduction of 39.6% for the yoke (from 5.38 to 3.24 tons) while maintaining transverse and integrated field homogeneity within the stringent [Formula: see text] tolerance threshold, and exhibits satisfactory excitation linearity. The design of this study can provide insight for the subsequent construction of a compact gantry.