On the role played by UV resonant photons in the electrical breakdown of an argon discharge initiated with an electron source

A Monte Carlo model for the initial phase of an argon discharge breakdown (1 Torr, 2.5 cm distance between two plane electrodes) is presented. The growth of the first avalanche and the beginning of the second one are simulated to determine which physical process is responsible for the secondary electron emission of the cathode. Measurements of the discharge formation time are made under the same conditions as for the model. The discharge is initiated with an electron source. We show that, in the frame of our study, the ions are too slow to play a role in the initial phase of the breakdown and that the UV resonant photons create the succession of electronic avalanches.