Directional electric breakdown of KCl single crystals

Abstract

Controversy exists about whether the discharge channel existing after breakdown in alkali halide crystals marks the path of the electronic instability or results from secondary processes. A fast electro-optical shutter has been used to observe the pre-breakdown light emission from KCl single crystals, and it has been found that the discharge channel does lie in the path of the electronic instability and that the latter does not necessarily occur in the field direction. It has been also demonstrated that the effect of mechanical strain in the crystals is to suppress the development of breakdown in directions other than the field direction.