表面电离的计算与测量

The calculation and measurement for surface ionization

通过对电离度和表面正离子流密度的计算以及对靶电流和负离子流的测量,对诸如钽、铁、钨、镍、铼和铂等高功函数金属表面的电离效率进行比较研究后表明:铁作为一种普通金属同样是较好的电离材料,并对影响表面电离的温度、铯蒸汽压力以及表面功函数进行了讨论。

The ionization efficiencies of the high work function metal sheets, such as Ta, Fe, W, Ni, Re and Pt ionizers, were studied and compared between them by calculating the degree of ionization and positive ion densities as well as measuring the target currents and negative ion beam intensities. It was shown that Fe as a kind of general metal, was also a better ionization material. The effects of surface temperature, pressure of cesium vapour and surface work function on the surface ionization process were also discussed.