A NEW METHOD FOR MEASURING THE SECONDARY ELECTRON EMISSION OF THERMIONIC CATHODE AND ITS APPLICATION

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