高阈值场发射屏蔽材料电性能实验研究

高域值场发射屏蔽材料为采用特殊工艺在不锈钢等金属材料表面覆盖一层绝缘薄膜,使金属表面的场致电子发射域值提高,有效防止金属材料表面局部场强过高导致电击穿的现象发生。为了检验和测试该屏蔽材料的实际性能,设计了屏蔽材料场发射域值的测试方案,采用电流测量方法判断经过屏蔽材料处理后的阴极头是否有电子发射,并通过阴极头的电压测试确定阴极头发射电子时的电压,通过数值模拟计算确定阴极头的发射域值。构建了实验测试平台,采用1 MV/100 kA电子加速器作为高压脉冲功率源,以平面二极管作为负载,二极管阴极头为实验样品。实验中分别测试了普通不锈钢阴极头的场发射域值和经过屏蔽材料处理后阴极头场发射域值,结果表明,普通不锈钢阴极头的场发射域值在450 kV/cm附近,而经过特殊工艺处理后的阴极头场发射域值在630 kV/cm附近,场发射域值约提高40%。

Experiment on Shielding Material with High Electron Emission Threshold

The shielding material with high electron emission threshold is a kind of dielectric film,which is planted on the surface of metal by special method.It can enhance electron emission threshold of the metal's surface in order to prevent high voltage pulse breakdown.For investigating the capability of shielding material,the scheme of experiment study on the shielding material is made.The current of the diode is taken as the evidence for judging the electron emission.The electric field when the electron is emitting first from the diode is taken as the emission threshold.The electron accelerator(1 MV/100 kA) is as the experiment's pulsed power source,the plane diode is as the load,the diode cathode is as studying object.In the experiment common steel cathode and the cathode with shielding material are tested.The results show that the emission threshold of common steel cathode is near to 450 kV/cm and the threshold of the cathode with shielding material is about 630 kV/cm.So the shielding material can increase the electron emission threshold of metal's surface,obviously 40%.