Breakdown delay in a vacuum

Breakdown delay in a vacuum is considered in terms of the Joule mechanism. The effect of the cathode material on the delay time is studied. A test for optimality for the gap electrode surface condition is stated. When prepared under optimal conditions, cathodes have a minimum field enhancement coefficient at surface microirregularities. This allows one to estimate the emission parameters of the cathode surface and the dielectric strength of vacuum insulation. (C) 2003 MAIK Nauka / Interperiodica.