I n-s i t u observation of microparticles in a vacuum-insulated gap using a scanning electron microscope

Results are presented of an investigation into microparticle activity in a vacuum-insulated 1-mm electrode gap. The experiments were conducted in situ in the specimen stage of a scanning electron microscope (SEM) and confirm microparticle activity at voltages well below breakdown. The most common size of the microparticles observed was 3 μm and very few particles above 10 μm were detected.