Performance Evaluation of High-Voltage Pulsed Power Modulator for Variable Pressure and Gap of DBD Plasma Load

High-voltage pulsed power modulators (HV-PPMs) play a key role in driving dielectric barrier discharge (DBD)-based excimer sources, where pulse rise time, voltage amplitude, and waveform shape directly influence discharge behavior and optical efficiency. In this work, an HV-PPM capable of delivering up to 8.0 kV is characterized using four DBD excimer tubes arranged into two operating configurations: one with fixed gas pressure and variable discharge gap, and another with fixed discharge gap and variable pressure. For both configurations, electrical-to-optical efficiency is measured as a function of applied voltage, enabling a comparative analysis of the efficiency–voltage characteristics. Rise-time variations with DBD voltage are also evaluated for all the tubes. At 8.0-kV applied voltage, the 222-nm emission intensity and the corresponding average electrical power to the DBD tubes are quantified to assess peak operating performance. The results show clear differences in efficiency trends between the two configurations, reflecting the influence of gap and pressure conditions on the generation of excimer radiation.