【摘要】 <正> 一、引言随着电子技术的发展,次级电子发射现象已经广泛地应用到各个领域中(如光电倍增管,电子倍增器,磁控管,正交场放大器,图像增强器等等),因而引起了很多学者的极大兴趣,并且进行了大量的研究工作。本文所研究的Cu-Al-Mg合金型次级电子发射体是用于正交场放更多还原

【Abstract】 The alloy type secondary electron emitters have been widely used as cold cathodes in high frequency Cross-field Am-plifiers and other devices. However, sometimes the emitters could not provide stable emission and satisfied life-time.Therefore, it is neccessary to recognize the characteristic of alloy type secondary electron emitters. The Cu-Al-Mg (6.43wt% of Al, 1. 44wt% of Mg) alloy which is one of the test secondary electron emitters for Cross-field Amplifiers hasbeen studied by means of SEM, XPS and SAM in combination with the measurement of secondary electron emissionyield. The surface compostion,the chemical state,and three-dimension distribution of Cu, Al, Mg, O as well as their in-fluence on the secondary electron emission yield have been observed from the Cu-Al-Mg alloys under different processingprocedures. From the results of investigation, a model for charaterizing the emission mechanism of Cu-Al-Mg alloy type sec-ondary electron emitters was proposed,that is,after suitable processing procedures,a MgO segregation layer forms atsurface of the Cu-Al-Mg alloy due to the segregation and migration of Mg along the grain boundaries of Cu and the com-bination of Mg with the absorbed oxygen,while the copper acts as a conducting frame. That results a significant increasein secondary electron emission yield. The value of secondary electron emission yield for Cu-Al-Mg mainly depends onthe segregation extent of MgO. Instead,Al exists in the form of ALOX and distributes nearly uniformly in three-dimen-sion and has little effect on secondary electron emission yield. It has also been concluded from the investigation that conventional polishing and acid etching procedures can hardlyproduce a MgO segregation layer for raising the secondary eletron emission yield,but an activating procedure at suitabletemperature and in oxygen atmosphere is the key to the improvement of Cu-Al-Mg alloy secondary electron emissioncharacteristics.更多还原