Study on the thermal effect of photon-induced electron emission enhancement

In order to investigate the thermal effect of photon-induced enhancement of electron emission, emissions from a diode with coated Ba-W cathode under different temperature & voltage conditions, and under certain irradiation of ultraviolet light were detected. The measured results were compared with theoretical results of thermo-optical-emission. Experiments showed that, the measured photon-induced enhancement of electron emission, as well as the quantum efficiency, remained almost the same at low values within a large temperature range, but increased dramatically from temperatures 100K-400K below the normal cathode operation temperature, with the maximum quantum efficiency reached 6.0×10^-2 at 1290K. Furthermore, apparent peaks appeared on tested ΔI-Va curves near knee-voltage points, which demonstrated different tendencies than theoretical estimated results.