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Enhancement of quality and lifetime of various electronic and optoelectronic devices, which contain micro-channel plates (MCP) for amplification of electron beams, is limited by undesirable ion secondary emission, produced by incident electrons. For long time it was supposed that hydrogen, hydroxyl and water ions have the main contribution to the desorbed ion yield, since in the production of MCP various wet technology are used. The purpose of the present work has been to study the composition of the emitted ions and to characterize the surface composition of MCP as function of temperature and incident electron beam using XPS, AES and SEM techniques. It was found, that sodium and potassium have important contribution to the desorbed ion yield. Ion emission rate of these elements increased with the increase of the surface temperature. Emission of water and hydroxyl ions was low at temperatures below 200 oC and negligible at higher temperatures. Heating accompanied by electron bombardment resulted in changes of the surface chemical composition, which consisted mainly in decrease of Na and K on the surface. To understand the complex behaviour of these elements under heating and electron bombardment a model of electron stimulated desorption and diffusion of ions in the bulk has been developed. |