A backtracking code and central region design of a compact superconducting cyclotron

This paper presents a backtracking code developed in MATLAB specifically for cyclotron central region design, along with an optimized design of the central region for an 18 MeV compact superconducting cyclotron intended for isotope production. Two methods for ensuring sufficient vertical focusing of the beam in the central region are described: one based on electric-field focusing and the other relying on enhanced flutter amplitude. These focusing strategies minimize beam loss and enhance transmission efficiency. In addition, a systematic and user-friendly backtracking code is introduced. Its algorithms are outlined, and its application to beam centering and matching in a cyclotron equipped with an internal ion source is demonstrated.