SECONDARY AND BACKSCATTERED ELECTRON YIELDS OF POLYMER SURFACE UNDER ELECTRON-BEAM IRRADIATION

The radiation behavior of a polymer surface has been investigated empl oying a scanning electron microscope (SEM). The charging, breakdown or flashover, and electron-blow-off phenomena caused by continuous irrad iation have been observed. By positively biasing the polymer surface, the backscattered electrons can be separated from the total electron e mission. This method has been applied for the determination of the sec ondary and backscattered electron yields of polymethylmethacrylate (PM MA), low density polyethylene (LDPE) and polytetrafluoroethylene (PTFE ) surfaces. The experimental results reveal that the secondary and bac kscattered electron yields are dependent on the incident electron beam energy by a power law when the energy is in the range of 5 keV to 35 keV. (C) 1997 Elsevier Science B.V.