230 MeV超导回旋加速器高频低电平系统设计与桌面实验研究

中国原子能科学研究院正在研发一台230 MeV医用超导回旋加速器，用于天津肿瘤医院的质子治疗项目。为满足加速器高频系统的腔体负载Dee电压稳定度、高频频率稳定度及加速电压幅度平衡度的要求，本文研制一套包含模拟数字混合型幅度环、数字型调谐环和数字型电压平衡环3个环路的低电平控制系统。该低电平系统通过串口与上位机进行通信，以实现本地调试；利用Profibus-DP通信协议，实现低电平系统和PLC组网的交互通信。在1个缩比例无氧铜实验腔体上完成了低电平系统低功率桌面实验与联合调试，验证了电压调平衡算法的有效性，并实现了低电平控制系统的一键启动，无需人工干预，满足了加速器高频系统对低电平控制系统的需求。

Design and Desktop Experiment of LLRF Systemfor CYCIAE-230 Superconducting Cyclotron

The CYCIAE-230 cyclotron is a proton beam accelerator that is dedicated to proton therapy. In order to meet the requirement of the cavity Dee voltage stability, RF frequency stability and acceleration voltage amplitude balance of the accelerator RF system, a set of low level RF (LLRF) system including the digital-analogue type amplitude loop, the digital tuned loop and the digital voltage balance loop was developed. The LLRF system communicates with the host computer through the serial port to realize the local debugging, and the communication between the LLRF system and the PLC network is realized by using the Profibus-DP communication protocol. The low power desktop experiment and the joint debugging were completed on an experimental cavity with a reduced scale oxygen-free copper. The validity of the voltage balance algorithm was validated, and a key start of the LLRF system was realized without human intervention. The LLRF system satisfies the demand of high frequency system.