介绍了BEPCII直线加速器速调管的特点,速调管在微波大功率老练和正常运行时容易在速调管陶瓷窗附近产生打火出气等不稳定现象,使附近的真空度产生变化,真空度的好坏对速调管陶瓷窗的寿命非常重要。四极质谱仪应用在大功率速调管上,记录了真空系统中残余气体的谱图。及在不同条件下残余气体的谱图变化特点。对速调管高功率输出时变化的残余气体谱图进行了初步分析。 The characteristics of BEPCII linear accelerator klystrons are introduced. Klystrons are easy to generate instability phenomena such as ignition and outgassing near the klystron ceramic windows during the high-power microwave operation and normal operation, resulting in the change of the vacuum degree nearby. The degree of vacuum The quality of klystron ceramic window is very important. Quadrupole mass spectrometer used in high-power klystron tube, recorded in the vacuum system, the residual gas spectrum. And the spectrum of residual gas changes under different conditions. A preliminary analysis of the residual gas spectrum of klystron at high power output was made.