A measurement of light intensity and quantum yield in photoelectron emission from satellite surface materials in the 30–250-nm range

We studied the measurement of photoelectron emission (PE) of metal and insulating materials used for thermal insulation on satellites or other such purposes. The PE measurement is very important for analyzing charge accumulation on satellite surfaces in a space environment because photoelectron emission is related to the amount of surface charge. Based on these photoemission characteristics, we deduce that the risk of electrostatic discharge for a satellite in the day position is lower than that in the night position. The synchrotron radiation source of the KEK-PF (High-Energy Accelerator Research Organization-Photon Factory), BL-20A, was used as a source of VUV (vacuum ultraviolet) radiation. Photoelectrons are collected by a semi-spherical electrode and measured at the electrode placed on the sample. The radiation wavelength range is 30-250 nm and the irradiated flux of VUV radiation is measured using Silicon (Si) photodiodes (International Radiation Detectors Inc. (IRD): AXUV100G) that were issued by the National Institute of Standards and Technology (NIST) for each wavelength to evaluate the quantum efficiency of the photoemission. We used the experimental results of the quantum efficiency of Au to confirm experimental set-up accuracy. We addressed the effect on photoemission of the carbon adhesive tape on the backside of the cover glass.