Breakdown Delay Times for Subnanosecond Gas Discharges at Pressures Below One Atmosphere
| Autor: | W. Justis, J. Chaparro, L.L. Hatfield, H.G. Krompholz, Andreas A. Neuber |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Nuclear and High Energy Physics
Argon Materials science Atmospheric pressure Physics::Instrumentation and Detectors Voltage divider chemistry.chemical_element Condensed Matter Physics Cathode Electric discharge in gases law.invention chemistry law Rise time Ionization Breakdown voltage Atomic physics |
| Zdroj: | IEEE Transactions on Plasma Science. 36:2505-2511 |
| ISSN: | 1939-9375 0093-3813 |
| DOI: | 10.1109/tps.2008.2004365 |
| Popis: | With a RADAN 303-A pulser (a rise time of 150 ps and a maximum voltage of 150 kV into matched load), fast breakdown in argon and air is investigated. An oil-filled coaxial transmission line is coupled with a lens to a biconical section and a radial millimeter-size gap operated at subatmospheric pressure. Diagnostics include capacitive voltage dividers which allow the determination of voltage across and current through the gap with a temporal resolution defined by the digitizer (20 Gs/s, 6 GHz) used. A scintillator-photomultiplier combination with different metal absorber foils and a temporal resolution of 2 ns is used as X-ray detector to obtain a rough energy spectrum of the X-rays and electrons in the range of 10-150 keV. Discharges are characterized by runaway electrons over much of the pressure range, with a strong excitation and ionization layer at the cathode surface, and ldquofree-fallrdquo conditions with negligible gaseous ionization for the rest of the gap. High-energy electrons (> 60 keV) are observed up to atmospheric pressure. Time-to-breakdown curves versus pressure have been measured for different applied voltage rise times. They resemble Paschen curves with a steep increase toward low pressure and a slow increase toward high pressure. The major experimental findings and particularly the time-to-breakdown curves are confirmed using simple force-equation modeling. Monte Carlo calculations simulating collisional ionizations and developing electron avalanches in three dimensions have been used to verify and explain the experimental results. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|