Development of low impedance nanosecond pulse generator and construction measurement environment

Abstract

The development of a short pulse generator is of paramount importance for various applications. Nanosecond pulse generators (NS-PG) which can generate a pulsed voltage with 5ns of duration and 2 ns of rise and fall times have been developed. Nanosecond pulsed discharges enable higher energy efficiencies of plasma processing, whose advantages include the ability to treat gas phases, allowing this device to be used for both the treatment of NOx and ozone generation. This is possible because the intense nanosecond pulsed streamer discharge is produced without inducing arc breakdown between the electrodes. This study focuses on improving our nanosecond pulse generator by changing its insulation and dielectric medium and improving the configuration of the spark gap switch (SGS). The insulation and dielectric medium were changed from silicone oil to ethylene glycol, with e r referring to the dielectric constant. The dielectric constant of silicone oil and ethylene glycol are respectively 2.7 and 44. Therefore, characteristic impedance of silicone oil and ethylene glycol are respectively about 50 Ω and 12.5 Ω. The pulse width in silicone oil was extended from 5.0ns to 20ns in ethylene glycol. Thus, pulse width can be varied by changing the length of the triaxial Blumlein line, with the length of the line 500 mm under the previous configuration but 120 mm using the reconfigured generator. The old gap switch path was longer than the one we have currently. Therefore, due to inductance inside the switch, we developed a low inductance new gap switch. We also developed five generators by combining the three previous factors. The output current of Generator 4 is about 2.6 times that of Generator 1. Generator 4 has the highest power, making it the best generator.