The uniformity of carbon stripper foils

Abstract The areal density of carbon foils produced by arc evaporation and glow discharge techniques has been measured with an areal resolution of 10 μm × 10 μm. The uniformity in areal density has been determined and studies of changes in areal density resulting from irradiation by 1.2 MeV Ar ions have been carried out. The consequences of the observed non-uniformities to the use of such foils as strippers in the high voltage terminal (20–30 MV) of tandem accelerators has been examined with respect to energy-loss straggling and multiple scattering and it is shown that except for the heaviest ions ( Z ⩾ 53) the non-uniformities in these foils do not give rise to significant reductiond in the beam quality. The magnitude of the decrease in thickness of carbon foils produced by glow discharge upon irradiation 1.2 MeV Ar ions is consistent with a decrease due to the loss of carbon atoms in the irradiated area resulting from sputtering.