Basic Research on Vacuum Breakdown and Field Emission Characteristics on SUS304 Electrode with Micro-sized Pits

In recent years, vacuum has attracted attention as an excellent insulating medium and is used in many high voltage and high electric fi eld equipment. To improve the performance and reliability of the equipment, it is essential to improve the electric strength, and more advanced insulation technology is required. In a previous study, it was reported that apertures and the number of apertures a ff ected the property of electron emission on electrodes with millimeter-sized apertures. Besides, micro-sized pits have been observed on electrode surface after chemical polishing and electric breakdown. However, it is not clear that how these micro-sized pits a ff ect electron emission, whether they cause vacuum breakdown, or not. Therefore, the purpose of this study was to investigate the e ff ect of micro-sized pits on electron emission. In this study, voltage-current measurement, and breakdown tests were conducted in vacuum using electrodes with and without micro-sized pits (5 mu m square side). In addition, electric fi eld simulations of electrodes with micro- or millimeter-sized pit were performed. From these results, it is considered that micro-sized pits have little e ff ect on fi eld electron emission and it is suggested that the micro-sized pits appeared after breakdown are probably generated by other physical processes following the breakdown.