炭素系材料表面からの２次電子放出と表面組成

Abstract

A new aspect of problems caused by secondary electron emission from a solid surface irradiated by energetic particles has recently emerged in some fields of science and industry. In a particle accelerator, for example, a problem of electron cloud instability has emerged. In this report, we focused on secondary electron emission from carbon materials to be compared with already reported some metals and TiNx materials. DLC (Diamond Like Carbon), diamond (110), amorphous carbon, HOPG (Highly Oriented Pyrolytic Graphite) and isotropic graphite were prepared to carry out a series of measurements of secondary electron yields (SEYs) and in-situ surface characterizations by X-ray photoelectron spectroscopy (XPS). The measurements were done under the surface conditions as follows; as-received, after electron beam irradiation and after sputter cleaning with Ar+ ion beam. The maximum SEYs in its primary electron energy dependence of carbon materials were found to be around 1 after sputter cleaning. These low SEYs for the carbon materials verified our hypothesis that graphitization at the surfaces by electron beam irradiation in UHV was a reason for decreases of SEYs for the metals and TiNx materials.