Convoy electrons in coincidence with Hq+ and Heq+ outgoing projectiles traversing carbon foils

We have measured convoy electrons produced by the passage of light ions (H+ at 150, 200, 250 keV/u and He+ at 100, 150, 200 keV/u) through equilibrium thickness carbon foils (ρx=5 μg/cm2) in coincidence with the charge states qf=0, 1 resp. qf=0, 1, 2 of the outgoing projectiles. All charge state fractions were registered simultaneously by a position sensitive parallel-plate-avalanche detector (PPAD). The yield of coincident convoy electrons Yc(qf) is normalized to the same number of outgoing probjectiles and mirrors the fraction of the emergent ions of each charge state qf. The FWHM of the coincident convoy electron peak is found to be independent of qf. A transport length λc for convoy electrons in the range of the mean free path of free electrons is deduced from the data. This result is in contradiction with recent measurements for D+ (150 keV/u). (orig.)