The Development Of The Fast Cathode Hot Child Components

This thesis focuses on improving the performance of fast warm-up cathode forsatisfying the application requirements when used in a decoy device. With the help ofheat conduction equations, the cathode supporting framework, the heater and itsassembly in the original cathode heater assembly are modified to improve the thermallyand mechanically structural performance of the assembly. Two different structuresincluding “little change” structural and “bracket” structural, both with the cathodediameter of Φ3.2mm, are designed for the fast warm-up cathode heater assembly. Thetransient thermal analysis software called ANSYS is used to simulate warming-upprocess of the two structures of cathode heater assembly. By comparing theirwarming-up performance in simulation and the manufacturing feasibility in practice, thefinal structure of cathode heater assembly is determined. In addition, such an improveddesign is manufactured with the help of technical backup of the cathode research lab.To validate the performance of the two proposed structures, some experiments areconducted to them for testing both the fast warming-up characteristics and the vibrationperformance.In the fast warming-up characteristics test, the fast warm-up cathode heaterassembly with “little change” structural is put in the traveling-wave tube. The testresults show that it takes7seconds when the tube has full power output and thecathode temperature reaches1000℃. The fast warming-up characteristics test is alsomade to the fast warm-up cathode heater assembly with “bracket” structural。For thisstructure, two assemblies (called1#and2#assembly, respectively) are realized, andthen tested in the situation where the assemblies in the glass box. For1#assembly case,when the heater is excited at5.0V, it takes7seconds to make the cathode temperaturereach1000℃. For2#assembly, when the heater is excited at5.5V, it takes7secondsfor the cathode temperature of1012℃. To our knowledge, the starting time can befurther reduced if the assemblies under the test are put in the electron gun ortraveling-wave tube。 Therefore， the proposed two type of fast warm-up cathodeheater assemblies both can satisfy the design requirement in this thesis: for the cathode with the diameter of3.2mm, the starting time is not larger than7seconds for thecathode temperature reaching1000℃.In the vibration experiment, the test results show that the fast warm-up cathodeassembly of “little change” structural can go through the vibration condition ofacceleration of100g and pulse width of2ms, which satisfies the design requirement ofthis thesis. Because of the electricity target，the fast warm-up cathode assembly of“bracket” structural wasn’t used in raveling-wave tubes， However, a similar structurecalled small multiple-beam fast warm-up cathode assembly has gone through the testcondition with50g acceleration and11ms pulse width. It is required to be furtherstudied whether such a structure can go through the condition of100g acceleration and2ms pulse width. nevertheless, the fast warm-up cathode assembly of “bracket”structural lays foundation for the applications of missile-borne traveling-wave tubewhich is required to have3-5seconds fast warm-up time in the future.In the last part of the thesis, some advice and though on the future research of fastwarm-up cathode heater assembly are presented.