GaAs光电阴极稳定性的光谱响应测试与分析

Spectral Response Measurement and Analysis of Stability for GaAs Photocathode

利用光谱响应测试仪对激活后的反射式GaAs(Cs ,O)光电阴极进行了稳定性测试 ,获得了阴极随时间变化的光谱响应曲线 ,并表征了阴极在衰减过程中的性能参数变化 结果表明 :积分灵敏度和峰值响应随着时间不断下降 ,截止波长向短波推移 ,表面逸出几率的下降是阴极衰减的直接原因 不同波长下光谱响应的衰减速率并不相同 ,波长越长 ,衰减速率越大 。

Spectral response measurement of stability for reflection-mode GaAs(Cs,O) photocathode has been carried by use of self-developing spectral response measurement instrument. Variations of spectral response curves of GaAs photocathode with time were obtained,and performance parameters of decayed photocathode were calculated. The results showed that integral sensitivity and peak response decreased with time,and threshold wavelength moved towards short wave,and decrease of surface escape probability directly is the direct cause of photocathode decay. The decrease rates of spectral response at different wavelength are different,spectral response at long wave behaves big decrease rate. It can be concluded that during sensitivity decrease long-wave spectral response ability also decrease.