Measurement of Quantum Efficiency for Spacecraft Materials and Noise Reduction of Photoelectron Current Waveform

摘要

Photoelectron emission is one of important factors in analyzing the spacecraft potential. In order to calculate the spacecraft potential in a space environment, it is necessary to know the characteristics of the quantum efficiency of the materials use in spacecraft design. Quantum efficiency measurements of spacecraft materials have been carried out by irradiating them with a pulsed monochromatic vacuum ultraviolet light using the beam line 20A of the High Energy Accelerator Research Organization (KEK-PF). The photoelectron current from cover glass materials was measured in the range 30-200 nm. A system for reducing the nois was designed that enabled accurate measurements in longer wavelength range (near 200 nm). The quantum efficiency characteristics of the cover glass materials had shown that for longer wavelength their value decreased from the maximum value 0.13 electrons/photons at 30 nm.