Results of lifetimes and surface irradiation behavior of thin (similar to 5
mug/cm(2)) carbon foils prepared by a mixed ion beam sputtering method are
given. The mean lifetime of the foils was 57.6 mC (4.6 h), which was about
15 times longer than that of conventional commercial foils under 3.2 MeV,N
e+ ion beam bombardment. The thin foil was also durable under carbon build-
up condition with normal non-bakable chamber.