Scandate cathode for TWT

Because of low work functions, the scandate cathode has a low operating temperature and high emission current density. However, it still has certain limit in application field for the shortcoming of emission uniformity and bad operating stability. After improving the manufacturing technology of tungsten sponge, stipulating reasonably the operating temperature, and adopting a stable module structure, the emission uniformity and capacity of the impregnated cathode has been ameliorated. If the power of heater change within /spl plusmn/5%, then the corresponding change of cathode temperature can be realized within 25-30/spl deg/C and the fluctuation of emission current less than /spl plusmn/ 2% in the application of TWTs in our company.