Speaker
Description
In pursuit of enhanced beam current and spatial efficiency in high-intensity cyclotrons, this study investigates a novel accelerator concept: the use of multiple axially separated orbits (multi-plane) operating under a common magnet system. A key challenge in such a configuration is maintaining isochronism across distinct axial planes, which critically depends on the uniformity of the magnetic field in the vertical z direction. This work presents a theoretical framework and numerical approach to quantify the magnetic field uniformity requirements necessary to preserve isochronous conditions for multi-plane orbits. An analytical framework is proposed to construct a 3D static magnetic field model of an axisymmetric multi-layer magnet, incorporating excitation coils and their positioning. The model focuses on the magnetic field distribution across multiple parallel orbit planes. Field distributions are evaluated on three parallel orbit planes (z = −Δz, 0, +Δz), and the deviation of magnetic induction δB(z)=(Bz−B0)/B0 is analyzed. Based on classical isochronous criteria, a quantitative threshold for the vertical field gradient ∂B/∂z is derived to ensure phase stability within ±10⁻³ relative deviation. This study provides design guidelines and performance limits for implementing synchronized multi-plane orbit systems within a single magnet, offering a pathway toward compact, high-current cyclotron architectures.
