A luminescent and fluorescent region associated with prebreakdown and breakdown in n-hexane

Abstract

A luminescent zone located midway between the corona and the starting point of the breakdown channel in liquid n-hexane with point-point electrodes has been photographed and traced with a microdensitometer. The luminescence zone is spherical in shape and approximately 200 mu m in diameter at a 10 mm gap length. The corona region is shown to belong to part of the luminescent zone while the breakdown channel is shown to initiate from the luminescent zone. After a short period of irradiation by a diffused UV source the luminescent zone fluoresces in darkness; it is invisible when illuminated by a tungsten filament lamp. Chemical reactions due to the electrical stress result in an absorbance in the near UV wavelengths which may be the explanation for the luminescent zone. Instead of point-injection to produce the corona, an applied dose of the UV energy can yield fluorescence of the whole luminescent zone.