BEPCⅡ直线加速器速调管的反射保护

为了使速调管陶瓷窗免受大功率微波反射信号的损伤，延长速调管使用寿命，要求当前反射信号功率超过阈值后，系统能够在下一个脉冲到达之前发出报警信号，进而切断触发信号，实现对速调管的保护。提出了3种较高性价比、易实施的方案，即PicoScope虚拟示波器的遮罩报警方案、基于自带检波和报警输出功能的芯片制作反射保护插件以及原功率计的升级改进。创新性地提出“3+1”反射保护响应时间测试法，并对上述3种方案进行详细测试。最终后两种方案取得较好的结果，综合考虑后，将改进型功率计作为最终实施方案。目前该改进型功率计已稳定可靠地上线运行超过1年。

Reflection protection of BEPCⅡ linear accelerator klystron

In the RF system of the accelerator, when the reflected power back to the klystron in the current RF pulse exceeds certain threshold, the system should send out an alarm signal before the next RF pulse arrives, and then cut off the trigger signal. By this way, the klystron ceramic window can be protected by reducing the damage caused by the high-power RF reflection; the online lifetime of the klystron can be prolonged. Three cost-effective and easy-to-implement solutions have been introduced: the mask alarm scheme by using the PicoScope virtual oscilloscope, the chip-made reflective protection plug-in based on the RF detection and alarm output functions, and the upgrade of the original RF power meter. The "3+1" reflection protection response time test method was innovatively proposed, it was used to thoroughly test the above three schemes. Finally, better results were obtained by using the latter two schemes. After comprehensive consideration, the upgraded RF power meter was used in the final implementation plan. At present, the upgraded RF power meter has been operating online stably and reliably for more than one year.