【摘要】 碳纳米管冷阴极具有良好的场致发射特性，在行波管的电子枪中具有潜在的应用前景。文中基于场致发射理论，研究了一支适用于G波段行波管的碳纳米管冷阴极带状注栅控电子枪。该电子枪由阴极、阴影栅、控制栅、聚焦极和阳极组成。阴极发射面为椭圆形，椭圆长半轴长度为0.8 mm,短半轴长度为0.4mm,两个栅极的开孔形状均为方格网状，而聚焦极通道形状为椭圆形，可以将电子注进一步压缩为带状注。文中分析了电子枪中电场分布以及不同阴影栅厚度对电子注的影响。CST模拟结果表明，当阴极电压为-24.6 kV时，电子枪的阴极发射电流为36.9 mA,射程为7.2 mm,注腰处的横向尺寸为0.52 mm×0.15 mm,电子注截面的面积压缩比为12.9,各电极均无电流截获。本研究为碳纳米管冷阴极应用于G波段行波管奠定了理论基础。更多还原

【Abstract】 Carbon nanotube cold cathode has excellent field emission characteristics and has potential application prospects in the electron gun of traveling-wave tubes. According to field emission theory, a sheet beam grid-controlled electron gun based on carbon nanotube cold cathode for G-band traveling-wave tubes is investigated. The electron gun is composed of a cathode, a shadow grid, a control grid, a focusing electrode and an anode. The cathode emission surface is elliptical with a semi-major axis length of 0.8 mm and a semi-minor axis length of 0.4 mm. Both grids have square mesh, while the focusing electrode has an elliptical tunnel to further compress the electron beam into a sheet beam. The electric field distribution in the electron gun and the influence of shadow grid thickness on the electron beam are analyzed. The simulation results of CST show that when the cathode voltage is-24.6 kV, the cathode emission current of the electron gun is 36.9 mA, with a range of 7.2 mm, a beam waist size of 0.52 mm × 0.15 mm, and an area compression ratio of 12.9. No current interception occurs at any electrode. This study lays a theoretical foundation for the application of carbon nanotube cold cathode to G-band traveling-wave tubes.更多还原