Investigation Of A Capacitor Voltage Divider For High Voltage Pulse Measurement In Intense Electron Beam Accelerator

Intense electron beam accelerators (IEBA) have been widely used in the field ofnational defense and industrial applications, such as nuclear explosion simulators,high power microwave generation, and electron beam pumped high power laser, et al.At present, increasing power, repetitive rate and the duration of the output pulse arethe important development trend for IEBA. So, it is very important to measure thepulsed voltage accurately. For the conventional resistive divider, the division ratio ischanged with the variance of the temperature of the water resistance, so it is not agood choice for such IEBA. Therefore, to measure the pulsed voltage accurately in theIEBA, the capacitive divider is investigated, and the main contributions of in thethesis are listed as follows.Firstly, the operating principle of the capacitive diver with self-integrating modeand D-dot mode is discussed, and the requirement of self-integrating is obtained whenthe measuring cable is taken into account. Meanwhile, the effect of the capacitanceand resistance of the integrating device on the measured waveform is investigatedunder the D-dot mode using a circuit-simulation code called PSpice.Secondly, a capacitive divider is designed to measure the charging voltage of thepulse forming line (PFL) of IEBA. The electric characteristic of capacitive divider isanalyzed theoretically，and the parameters of capacitive divider are calculated andmeasured by experiments．The division ratio of the capacitive divider is about216200．Meanwhile, the effect of the measuring cable on the waveform is analyzed.The experiment results show that the capacitive divider could be used to measure thecharging voltage of PFL with voltage of about700kV and charging time of10s.At last, a capacitive divider is designed to measure the output voltage of IEBA.The structure of the capacitive divider is described in detail, and the capacitance valueof the capacitive divider is calculated by theoretical analysis and electromagneticsimulation. The dependence of the measured voltage on the electrical parameters suchas the stray capacitance, earth capacitance of the front resistance is obtained byPSpice simulation. In the experiment study, the capacitive divider is used to measurethe output voltage of the IEBA, and the waveform is accordance with that measuredby a resistive divider, the division ratio is about563007. The experiment result indicates that the designed capacitive divider is satisfactory to measure the outputvoltage of IEBA with voltage of about470kV and pulse duration of about100ns.