In order to develop the high-gradient insulator

the physical mechanism of excellent performance in surface flashover of the novel insulator had been introduced.The preliminary ration estimation to the insulating layer thickness had been made with the single electron theory.The superiority of Kapton used in the high voltage vacuum insulation had been discussed on several aspects such as the thermal stability

out gas rate

the relative permittivity

the irradiation-resistant ability

etc.The graph of the relations of the number of secondary electron emission changing along with the incident electron energy of Kapton has been drawn up too in this thesis using the empirical formula.These endeavors have reference value for the objective of designing the microstack insulator in reality.