Design Of Compact Cyclotrons In Virtual Prototyping Environment

The compact cyclotron is a very flexible and economical accelerator, which is not only an important tool for fundamental science such as nuclear and solid-state physics research, but also widely employed in PET (Positron Emission Tomography) system, proton therapy, isotopes production and industrial radiation. We applied VP (Virtual Prototyping) technique in the design and development processes of compact cyclotrons, which conduces to generating innovational schemes and reducing risks. With the guide of beam dynamics theory, this thesis describes the design study for the main magnet, the axial injection system and some related components of cyclotrons in the integrated VP environment. The experimental results agree well with the numerical simulation of magnet fields and beam behavior.First of all, the basic beam dynamics including transverse and longitudinal motion with their stability underlying compact cyclotrons are reviewed. The numerical analysis and calculation method of equilibrium orbits, phase shift and tune in cyclotrons is discussed.With Runge-Kutta integration on particles motion equations, we can obtain beam particles trajectories and perform related beam dynamics analysis. Base on this method, a code named PTP (Particle Tracking Package) is designed and implemented with C++ and Python languages. The results of PTP agree well with the TRIUMF code CYCLOP.The main magnet is the most expansive part in cyclotrons, which has stringent design tolerances. The magnetic field distribution should fulfill requirements of isochronisms and transverse focusing of the beam, as well as to avoid dangerous resonance crossing. The main design considerations of the main magnet are summarized. And an automated magnet design and optimization method with the collaboration between beam dynamics analysis and magnet FEM (finite elements method) calculation is studied.The axial injection system is the key facility of achieving high intensity beam and high transport efficiency. This thesis studied the optics design of a 16 MeV cyclotron axial injection line with the TRACE3D code. The analytical and numerical design study of the spiral injector is described.The VP integrated platform is a large-scale software and has numerous loose-coupled components. A pythonic approach and implementation with heterogeneous feature is proposed, which achieves a combination of code efficiency, flexibility and compactness.Experimental study of physical prototypes is very important to validate numerical results in VP environment. Two experiments are introduced. One is the beam measurement of the Injector ring of FFAG Complex in KURRI. The other is the magnet field measurement of a 10 MeV prototype cyclotron in CIAE. The experiment results show good agreement with the numerical simulation of beam dynamics and magnet field.