Nanosecond pulse generators for microdischarge excimer lamps

Abstract

Pulsed electron heating causes an increase in electron temperature with negligible gas heating, as long as the pulse duration is comparable to or less than the relaxation time of the electrons in the discharge plasma. For atmospheric pressure plasmas this is tens of ns. Since the sustaining voltage of microhollow cathode discharges is only 200 V, pulsed voltages of up to 1 kV are sufficient to increase the electron temperature in these plasmas considerably. A combination utilizing a MOSFET as a switch with a pulse forming network (PFN) in a Blumlein configuration has provided pulses with FWHM down to 10 ns, and rise and fall times of 4 ns. Applying these short pulses to DC microhollow cathode discharges resulted in significant increases in excimer emission, and, for xenon discharges, in excimer efficiency.