高能电子成像直线加速器低电平控制系统研制

为了能开展高能电子成像相关实验研究，中国科学院近代物理研究所建造了一台S波段的射频电子直线加速器。为保证实验用束流品质和加速器稳定运行的要求，设计了一套低电平控制系统，利用上下变频、IQ解调技术，实现了相位的反馈控制。本文介绍了低电平控制系统的设计及数字化算法的实现，给出了系统闭环实验的测试结果，实现相位控制精度达到±0.5°(峰峰值)和0.110 8°(均方根)。该系统利用成熟的商业化模拟微波器件和相关的PXI板卡实现，基于LabVIEW软件开发了相关的控制程序和界面，具有搭建方便、开发时间短、结构简单紧凑、易于使用和维护的特点。

Development of Low Level Radio Frequency Control System for Electron Linac of High Energy Electron Radiography

An electron linac was built at Institute of Modern Physics, Chinese Academy of Sciences, dedicated for high energy electron radiography experimental study. In order to satisfy the requirement of the experiment and stable linac operation, a low level radio frequency control system was designed, which achieved phase feedback control by using up-down converter and IQ demodulation techniques. In this paper, the design principle and digital algorithm of the low level radio frequency control system were introduced and the result of the closed loop test was given. The low level radio frequency control system achieves phase stability control accuracy of ±0.5° (peak to peak value) and 0.110 8° (root mean square), meeting the design goal. The low level radio frequency control system was built with commercial analog microwave device and mature commercial PXI card, and the control program was realized with LabVIEW software. The system has the characteristics of fast building, easy developing and realizing, compact structure and convenient use and maintain.