The influence of defects on the insulation properties of dielectric materials along the vacuum surface under pulse voltage was studied by positron annihilation lifetime spectroscopy(PALS).The Chenguang accelerator tested the insulation properties of four kinds of materials along the vacuum surface.The results show that the longer the average lifetime of positron annihilation,the worse the voltage-withstanding performance along the vacuum surface of dielectric material.The defect information in the material can be quantified by the average lifetime of positron annihilation.Our analysis suggests that the presence of defects is a key factor in the reduced insulation performance along the vacuum surface of dielectric materials.Defects on the dielectric material's surface cause the material's dielectric constant to change,and defects can easily capture free carriers,arouse surface charge accumulation,and enhance the local electric field.
关键词
正电子湮没寿命/缺陷/电荷集聚/沿面闪络/脉冲电压/介电材料
Key words
positron annihilation lifetime/defect/charge accumulation/surface flashover/pulse voltage/dielectric material
万方数据