多晶LaB6阴极的脉冲热发射特性
Pulse thermionic emission performance of multi-crystal LaB6 cathode
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摘要: 采用多晶LaB6材料制成平板二极管阴极，阳极采用钼材料，阴极采用热传导与热辐射加热，加热体为石墨。实验研究了不同阴极温度、不同真空度下的脉冲发射特性，并对热发射稳定性进行了分析。结果表明： 在动态真空系统中， 阴极发射面积为0.012 1 cm2， 工作真空度为2×10-4 Pa， 阴极温度分别为1 600， 1 650和1 700 ℃，在脉冲宽度为40 ms、重复频率为107 Hz的条件下，最大脉冲发射电流密度分别为34.0，44.0和53.8 A/cm2; 2×10-4，5×10-4和2×10-3 Pa压强下的发射能力没有明显的差异;脉冲宽度的变化不影响发射电流密度的变化。Abstract: A flat-plate diode cathode was produced using multi-crystal lanthanum hexaboride(LaB6) material. The anode was molybdenum, and the cathode was heated by thermal conduction and radiated with a graphite heater. The pulse emission properties and the emission stabilities were investigated at different cathode temperature and under different vacuum level. When the LaB6 cathode with an emission area of 0.012 1 cm2 was operated at 1 600 ℃, 1 650 ℃, 1 700 ℃, respectively, the corresponding maximum of pulse thermionic emission current densities were 34.0 A/cm2, 44.0 A/cm2, 53.8 A/cm2, under 2×10-4 Pa, the pulse width of 40 ms, and repetition frequency of 107 Hz. The pulse thermionic emission density of LaB6 cathode was also measured under 2×10-4 Pa, 5×10-4 Pa, 2×10-3 Pa, respectively, and it
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