Diagnosis and application of electron beams generated by gated field-emitter arrays

研究了场发射阵列阴极电子枪产生的电子束，并应用于产生可见的史密斯-珀塞尔辐射。电子束的几何特性利用图像处理器对FEA在1 m处形成的荧光图案进行分析，对电子束进行诊断，每个针尖发射的小束的均方根归一化发射度范围为10 μ <-8>~ 10 μ <-9>π m-rad。光束的光斑尺寸近似等于FEAs的发射区域的尺寸。束加速到120千伏安的高电压被施加到阴极的小型货车德格拉夫发生器配备有反馈控制系统。cahode柄通过四个陶瓷绝缘体，额定电压为30 kV，以实现高达120 keV的光束能量。Smith-Purcell辐射的产生Smith-Purcell光是由15-60 keV电子束掠过复制衍射光栅而发射的。光谱的自动扫描测量覆盖350-750 nm波长，并检测到辐射阶数为-2至-5.4的峰。光电场发射当用100 mW YAG激光（2ω_o）光束照射FEA时，电子发射显著增加，该光束聚焦到10^7 W/m^2的数量级。

Electron beams produced by a triode gun with a field-emitter array (FEA) cathode were examined and applied to generate visible Smith-Purcell radiation.1. Charactereistics of the electron beamThe beam was diagnosed by means of image processor which analyzed fluorescent patterens formed at 1 m from the FEA.The rms normalized emittance of beamlet emitted from each tip was in the range of 10^<-8> to 10^<-9> π m-rad. The spot size of the beam was approximately equal to the size of the emitting area of FEAs.2. Beam acceleration up to 120 keVA high voltage was applied to the cathode by a small Van de Graaff generator equipped with a feedback control system. The cahode shank was passed through four ceramic isolators rated at 30 kV to achieve beam energies up to 120 keV.3. Generation of Smith-Purcell radiationSmith-Purcell light was emitted by 15-60 keV electron beams grazing a replica diffraction grating. Automatic scanning measurement of spectra covered 350-750 nm wavelengths and detected the peaks for radiation orders of -2 to -5.4. Photoelectric field emissionThe electron emission increased significantly when illuminating the FEA with a 100 mW YAG laser (2ω_o) beam which was focused to the order of 10^7 W/m^2.