Effect of impurities in charge-exchange carbon foil on foil thickness reduction

► The foil thickness seemed to have decreased by beam irradiation; however, the main cause of this phenomenon remains unknown. ► We seek the cause of decrease in foil thickness by studying the relations between the gases released and foil thickness. ► The residual gas was measured by using partial pressure vacuum gauge, and the contained elements were analyzed with RBS. ► We found that the presence of oxygen is the main cause of decrease in foil thickness.