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Photoemission and secondary electron emission yields are necessary to calculate the equilibrium spacecraft potential. Nowadays, spacecraft charging investigations are focused primarily on surface effects and spacecraft external surface design issues. In this work, kapton and upilex polyimides, polyethylene and betacloth for space applications have been studied. The polymers were characterized by x-ray photoemission spectroscopy, ultraviolet photoemission yield and secondary electron emission yield measurements, scanning electron microscopy, and infrared spectroscopy. In the study of surfaces with space interest, one of the most important properties to analyse is the photoemission threshold taken as the minimum energy required for removing one electron out of the surface to infinity. For photoemission threshold measurements the onset method was used having X-ray radiation as the primary excitation source (Mg anode, 1253.6 eV). With the sample biased in the range -5 to -50 V the spectrum of secondary electron emission induced by X-rays was measured. The spectra were obtained with a hemispherical energy analyser with 1 eV pass energy. These measurements were completed by simultaneous spectroscopy of the valence band. The work function depends upon the surface composition, defects, surface roughness and temperature. The surface potential as a function of the sample bias shows a nearly-lineal variation. The different slopes of this function were related to the dielectric constant of the polymer thin films. Infrared spectroscopy results were correlated with the composition obtained by x-ray photoemission spectroscopy. The secondary electron emission yield as a function of the primary electron energy (5 – 5000 eV) was obtained for those polymers using a single primary electron pulse of about 106 e-. The maximum secondary electron emission coefficient was correlated with the polymer molecular weight and the number valence electrons.
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