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

研究了场发射极阵列(FEA)阴极三极管枪产生的电子束，并将其应用于产生可见的Smith-Purcell辐射。电子束特性利用图像处理器对在距FEA 1m处形成的荧光图案进行分析来诊断电子束。每个尖端发射的电子束的均方根归一化发射度在10^~9πm-rad的范围内。光束的光斑大小与FEAs的发射区大小大致相同。通过配备反馈控制系统的小型Van de Graaff发电机将高达120Keva的束流加速施加到阴极上。通过四个额定电压为30千伏的陶瓷隔离器，使束流能量达到120keV.3。史密斯-珀塞尔辐射的产生史密斯-珀塞尔光是由15-60keV的电子束掠过复制的衍射光栅发出的。光谱的自动扫描测量覆盖350-750 nm波长，并检测到辐射数量级为-2至-5.4的峰值。用10 0 mW激光(2ω_o)聚焦到10~(-7)W/m~2量级时，电子发射显著增加。

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.