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In order to enhance the emission current, reduce the operating temperature and prolong the lifetime of the pure W filament cathode for application in high-power (i.e., more than 10KW) continuous wave magnetron tube, a novel Y2O3-Gd2O3-HfO2 impregnated W base direct-heated cathode (Y-Gd-Hf-O impregnated cathode) has been developed. At 1700°br, the dc emission density of the Y-Gd-Hf-O impregnated cathode...
In order to enhance output power and prolong lifetime of the high-power continuous wave magnetron tubes, a novel La2Zr2O7 impregnated cathode is adopted to enhance the thermionic emission. In this abstract, we compare the thermionic emission ability of this cathode with traditional pure W filament cathode. Experimental results show that this cathode can provide the same thermionic emission with at...
Energy and local distribution of electron around the cathode have been simulated in a 30kW continuous wave magnetron tube which operates in normal output power. According to the simulation results, it is clearly that the cathode of magnetron is bombed by low energy electrons mostly among 0 and 2keV. Based on the fact that most of the back bombardment electron belong to low energy electron, when the...
The oxide cathode is one of the most commonly used electron sources in vacuum tubes. Continual improvement of vacuum tubes requires better and better current emission performance of their electron sources. In this context, new type oxide cathodes have been emerging incessantly in the past century, such as Ni sponge oxide cathode, rare oxide cathode and reservoir oxide cathode. Nonetheless, there is...
Different treatments on the cathode surface are adopted to enhance the secondary electron emission(SEE)of the cathode in high-power continuous wave magnetron tubes, which show that SEE coefficient of the pure tungsten cathode sprayed sand for coarseness and coated W-Re5%wt film is higher than that of untreated pure tungsten cathode.
In this paper we mainly describes the research progress in a kind of ammonium perrhenate impregnated Ni sponge oxide cathode, which includes the preparation of Ni-Re sponge layer by impregnated ammonium perrhenate solution and the cathode properties testing. The testing results show that the pc emission current density of the cathode reaches 35.6A/cm2 with a 10μs pulse width at a temperature of 850U...
Amplification studies of a Ka-band harmonic-multiplying gyrotron traveling-wave tube (gyro-TWT) are reported. A coupled cavity with inner- and outer-intersecting couplings and precise control of the focusing magnetic field are used to improve the coupling between the fundamental and the harmonic and to adapt the sensitivity of the effect of focusing magnetic field on the beam-wave interaction in the...
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