Speaker
Description
Ultra-compact SC cyclotrons for high-intensity medical isotope production pose unprecedented central region design challenges. Strong magnetic fields, compact geometry, and intense space charge effects generate complex focusing conditions where conventional design approaches prove inadequate. In the central region, magnetic focusing is negligible due to minimal azimuthal field variation, while low-energy ions are dominated by electric forces from RF acceleration gaps. High current beam requirements impose stringent electrode design constraints, as poor vertical acceptance directly compromises beam quality. This study investigates electric focusing mechanisms in the central region of an ultra-compact SC cyclotron under development at CIAE for and H_2^+ dual-beam acceleration. Through mathematical modeling and Hilbert transform-based numerical fitting of simulation data, we quantitatively determine the vertical betatron tune νz and systematically compare electric and magnetic focusing contributions. The methodology combines analytical derivations with numerical techniques to determine focusing parameters from particle tracking simulations. Results reveal the relative importance of electric versus magnetic focusing under intense space charge and strong magnetic field conditions. The findings provide critical insights for optimizing electrode geometry and maximizing vertical acceptance, offering design guidance for improved extracted beam quality in medical isotope production.
Funding Agency
This work was supported by the National Natural Science Foundation of China under Grant of 12427810.
Footnotes
*: Corresponding Author, Tianjue Zhang: tjzhang@cnncmail.cn
