New method for measuring secondary electron emission of thermionic cathode and its application

Abstract

By using correlation-detection technique and improving structure of the test tube, the background noise of thermionic-electrons and space charge effect are restrained. The secondary emission coefficient δ of thermionic cathode at high temperature has been studied. The δ of impregnated scandate cathodes increases exponentially with increasing temperature at low energy and current of the bombardment electrons; at high energy or current of the bombardment electrons the temperature has little effect on δ. The research shows that an enhanced thermionic emission occurred when the cathode works at high temperature and under electron bombardment. These phenomena are discussed in terms of “internal field model”.