碳纤维阴极的场致发射特性实验研究

 研究了具有一定导电性能的碳纤维的直流场致发射电子束特性，实验分别在大气环境、低真空（10^-1 Pa）及高真空(10^-5 Pa)环境下进行。实验结果表明，碳纤维具有一定的场致发射能力，并且发射特性和发射环境的真空度密切相关。在大气环境下，发射电子束流与所施加的电压符合Fowler-Nordheim关系，当电压为7 kV，电流为61.4 μA时，根据Fowler-Nordheim定理推算出碳纤维场致发射场增强因子为3.75×10⁵。在低真空条件下阳极只收集到微弱的电流；在高真空条件下，阴极发射明显，在较低电压下就能观测到阳极电流，放电前阳极最高电流是大气条件下的3~4倍，发射的束流大小和所施加在尖端的电压关系接近Child-Langmiur定律。

Experimental research on field emission of carbon fiber

Electric carbon fiber is a promising material to emit cold electron under intensive electric field. Experiment was conducted to test carbon fiber’s emission at the pressures of 0.1 MPa, 10-1 Pa and 10-5 Pa. The diode gap between the fiber tip and the electron collecting anode was about 5 mm. In atmosphere, the applied voltage and the emitted current have a Fowler-Nordheim relation. According to Fowler-Nordheim theorem, the field intensified factor was 3.75×105 when the voltage was 7 kV and the current was 61.4 μA. In low vacuum (about 10-1 Pa) condition, the anode collected current only less than 10 μA under 20 kV. In high vacuum (about 10-5 Pa) condition, the anode collected larger anode current up to 300 μA without flashover, the relation between voltage and current was close to the