TARGET TEMPERATURE-DEPENDENCE OF CHARGE STATE DISTRIBUTIONS OF FAST HE-IONS EMERGING FROM SOLIDS

We have measured the charge state distributions of fast helium ions backscattered from various thick targets which are kept at high temperature. For metal targets the charge state distributions start to change at about 400°C and reach equilibrium at about 800°C. Furthermore, it has been also found that these equilibrated charge state distributions at high temperature depend strongly on the target materials. We have assumed that the variation of charge state distributions at various temperatures corresponds to the variation of the thickness of the contaminating layer of light atoms and have estimated the thickness of the adsorbed layer on the target surface at different temperatures. Measurements have also been made for Bi and Sn targets in liquid states. © 1979.