论文部分内容阅读
采用磁控管做功率源的低能电子直线加速器在医疗、辐照、X射线检测等领域得到较为广泛的应用。磁控管产生的微波信号输入到加速管,对电子束进行加速,磁控管的工作频率稳定性对加速器电子束能量、能散及发射度产生直接的影响。但磁控管是一种振荡器,其频率受到温度、振动、负载牵引的影响会产生漂移,所以需要一套自动频率控制系统(Automatic Frequency Control,AFC)机构对磁控管进行频率控制。目前普遍采用的AFC机构主要是行波控相或双腔鉴频,对两路检波信号差分放大进而控制伺服电机进行调谐的方法实现磁控管的频率稳定。随着数字化I/Q和FPGA(Field-Programmable Gate Array)技术的不断发展,运用该技术进行磁控管的频率控制完全具备可行性。本文从理论和工程设计上阐述了数字化I/Q技术在磁控管频率控制上的应用。
The low energy electron linear accelerator using magnetron as the power source has been widely used in the fields of medical treatment, irradiation, X-ray detection and the like. The microwave signal generated by the magnetron is input to the accelerating tube to accelerate the electron beam. The working frequency stability of the magnetron has a direct influence on the energy, dispersion and emission of the electron beam of the accelerator. However, a magnetron is an oscillator whose frequency is drifted due to temperature, vibration and load drag. Therefore, an automatic frequency control (AFC) mechanism is needed to control the frequency of the magnetron. Currently widely used AFC institutions mainly traveling-wave phase-control or dual-cavity frequency discrimination, the two detection signal differential amplifier and then control the servo motor tuning method to achieve frequency stability of the magnetron. With the continuous development of digital I / Q and FPGA (Field-Programmable Gate Array) technology, the magnetron frequency control using this technology is fully feasible. This article elaborates the application of digital I / Q technology in magnetron frequency control from theory and engineering design.