In accordance with the recent expansion of ion microprobe applications, many efforts have been devoted to increasing the ion current in order to obtain better statistics. Extremely high current density, however, causes a serious problem because of radiation damage in the sample. In order to reduce the beam effect as much as possible, we have designed and fabricated an annular type SSD for RBS. To investigate the mechanism of radiation induced effects, we have added a SEM column to the target chamber.