S波段同轴耦合结构驻波加速管设计与仿真

Design and Simulation of S-Band Coaxial Coupled Standing Wave Accelerators

随着术中放疗、FLASH放疗等医疗技术的发展,对医用电子直线加速器的技术要求更高,本文设计了一款适用于FLASH放疗的中高能S波段同轴耦合驻波加速管。其同轴耦合结构结合了边耦合结构稳定性高和传统轴耦合结构对称性好、易于加工装配等优势。该结构有利于设计外形尺寸更加紧凑的,易于维护和低成本的中高能加速管,适用于新一代中高能医疗加速器。通过CST仿真优化后的同轴耦合加速管整体Q值达到了17024,分路阻抗达到163 MΩ/m,整体性能优于轴耦合结构并十分接近边耦合结构。通过粒子动力学仿真,该加速管束流输出能量大于18 MeV、脉冲流强达到295 mA、俘获率为42%。

With the development of intraoperative radiotherapy,FLASH radiotherapy and other medical technologies,the technical requirements of medical electron linear accelerator are higher.A medium and high energy S-band coaxial coupled standing wave accelerator tube suitable for FLASH radiotherapy is designed.The coaxial coupled structure combines the advantages of high stability of the side coupled structure and good symmetry and ease of processing and assembling of traditional on-axis coupled structure.It is beneficial to design more compact,easy maintenance and low-cost accelerator tubes suitable for the new generation of medium and high energy medical accelerators.By using CST simulation optimization,the overall Q value of the coaxial coupling accelerator tube reaches 17024,and the shunt impedance reaches 163 MΩ/m.The overall performance of the coaxial coupled accelerator tube is better than that of the on-axis coupled structure and very close to that of the side coupled structure.The particle dynamics simulation of the accelerator tube shows that the beam output energy is greater than 18 MeV,the pulse current intensity is up to 295 mA,and the capture rate is up to 42%.