3GHz边耦合直线加速结构单元腔优化设计

Optimal Design of Unit Cavity in 3 GHz Side-Coupled Linear Acceleration Structure

利用CST studio suite程序对边耦合直线加速结构的加速腔及耦合腔进行建模仿真,并进行优化。加速腔结构由11个参数决定,优化过程需平衡多个参数,包括本征模式、高频特性、最大表面电场、有效分路阻抗及渡越时间因子;耦合腔的优化基于维持本征模式3 GHz。结果表明,在26~120 MeV整个加速过程中,加速腔的有效分路阻抗为22.5~59.8 MΩ·m^(-1),加速梯度为11~14.7 MV·m^(-1)。

Based on the 26 MeV proton beam from the cyclotron,the proton beam is re-accelerated by using the side-coupled linear acceleration structure.The acceleration cavity and the coupled cavity in 3 GHz side-coupled linear accelerator are modeled and simulated with the help of the CST studio suite program,and the cavity parameters are optimized under the premise of high-frequency parameters.Finally,the effective shunt impedance R eff of the acceleration cavity varies from 22.5 MΩ·m^(-1) to 59.8 MΩ·m^(-1),and the acceleration gradient E acc,K varies from 11 MV·m^(-1) to 14.7 MV·m^(-1) during the acceleration process.The research has effectively improved the proton beam energy and can provide data support for the construction of medical proton acceleration in China.