An Improved Match Method of Capacitive Divider for Measurement of Nanosecond-Range HV Pulses

Abstract

In this paper, a new match circuit of the capacitive divider is studied. Using the proposed match circuit, the signal measured by the capacitive divider will not be secondarily attenuated near the accelerator, and the secondary attenuation is done at the terminal end of the cable which is located in a shielding room with a good electromagnetic environment. So, the proposed circuit has a better anti-interference capability than the traditional terminal-end match circuit. The result of the theoretic analysis shows that the proposed match circuit is equivalent with the traditional terminal-end match circuit when the parameters of the circuit are well chosen. Rectangular pulse response of the proposed match circuit is tested based on an equivalent circuit. It shows that the proposed match circuit has a good pulse response characteristic for rectangular pulse with a rise time of 5 ns, and the output waveform of the match circuit has a flattop jitter less than 1%. The match circuit proposed in this paper is utilized to measure the diode voltage of the accelerator in our laboratory. It is found that the high-frequency interference on the output waveform measured by the new match circuit is much smaller than that measured by the traditional terminal-end match circuit, which proves that the match circuit proposed in this paper is an effective method for increasing the signal-to-noise ratio of capacitive divider for measurement of nanosecond-range HV pulse.