GaAs/GaAlAs透射式光电阴极发射电子的平均横向能量

用扫描电镜观测了 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式光电阴极的表面形貌，计算了阴极表面形貌对阴极发射电子的平均横向能量的贡献，测量了阴极激活过程中阴极发射电子的平均横向能量随激活时间的变化。结果表明， Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 阴极表层的 Ｃｓ／ Ｏ 激活层对电子的散射是导致阴极发射电子的平均横向能量值增高的根本原因。最后提出减少阴极发射电子的平均横向能量的技术途径。

Mean transverse energy of electrons emitted from GaAs/GaAlAs transmission photocathode

A GaAs/GaAlAs transmission photocathode surface topography is examined with a scanning electron microscope in the secondary emission mode. Contributions of photocathode surface topography to mean transverse energy of electrons emitted from photocathode are calculated. Measurement is made of the variation of mean transverse emission energy with activating time during the course of activation. It is shown that the scattering of the photoelectrons in the Cs/O layer is the primary cause of the unexpectedly high values of the mean transverse energy of electrons emitted from GaAs/GaAlAs photocathode. A method is proposed for the reduction of the mean transverse energy of electrons emitted from photocathode.