通过对回旋电子束形成的电位和电场分布，推导出电子束横纵速度比测量的计算式。提出将电子束作传输线内导体等效，采用陶瓷电容分压器来测量速度比的方法。介绍了该测量装置的设计和加工工艺，及陶瓷电容分压器的标定方法和结果分析，并介绍了初步的原理性实验结果。该测试方法装置简单,测试电子束横纵速度比时不会破坏电子束的特性,能够做到在回旋管运行时在线测量,实时监测电子束质量。

By theoretical analysis of potential and electric field distribution of a gyrotron electron beam, the formula of velocity ratio measurements is presented. The electron beam is equivalent to transmission-line inner conductor. A ceramic capacitance divider is proposed for velocity ratio measurements. The design and processing technique of the measurement system, the calibration method and result interpretation of the ceramic capacitance divider are presented. At last, the result of primary experiment is introduced. Capacitance divider was selected for the velocity ratio measurement because it does not perturb the electron beam and normal operation of the gyrotron is preserved as a result. This technology can be used to guide the design of magnetron injection gun and the gyrotron experiments.