Attenuation Mechanism of Secondary Electron Effect of MgO Film Under Electron Bombardment

To improve the secondary electron emission coefficient and attenuation characteristic becomes the key to the application technology. Taking MgO film and MgO/Au composite films as the research objects of secondary electron emission materials, the change law of secondary electron effect over time is revealed by continuous electron beam bombardment on the film. The exponential decay of the sample time was tested and the influence of conductivity and dielectric constant on attenuation rate was explored. The mechanism of secondary electron emission was discussed under model hypothesis. The concept of potential electron and tablet capacitance model were put forward, and the theory model of the secondary electron emission process was then established. The expression of experimental value of the induced current and the secondary electron emission coefficient was obtained and coincided with the test result trend of actual sample, namely, the attenuation rate of secondary electron emission material properties was positively correlated to the film conductivity. It is concluded that the proposed theoretical model effectively explains the attenuation mechanism of the dielectric film secondary electron emission, and facilitates improving the attenuation performance of secondary electron emission material.