Relationship between field emission current characteristic and electrical breakdown in vacuum

It has been assumed that an electrical breakdown in vacuum is caused by field emission electrons emitted from a cathode surface. And these field emission electrons emitted from microprotrusions on the cathode surface. It has been recognized that this electron's current is expressed by F-N theory. Therefore, it is thought that a characteristic of a field emission current has influence on the electrical breakdown in vacuum. In this study, the electrical breakdown voltage in vacuum gap was measured in order to investigate whether the correlation exists between this voltage and the characteristic of the field emission current. At this time, the field emission current was measured from appearance of electron to just before electrical breakdown in vacuum, by using a Micro Channel Plate (MCP) and a pico-ammeter. As the result, it is guessed that the characteristic of field emission current has influence on the electrical breakdown. Because the applied voltage to keep the same field emission current correlates to the electrical breakdown voltage in all cathodes when the field emission current is near to the electrical breakdown.