Effects of the Coulomb explosion on the transmission of molecular ions through a tandem

When foils alone are used to strip a molecular ion beam in a tandem Van de Graaff an energy spread ranging from 20 to over 100 keV will inevitably be introduced into the beam over and above the energy spread caused by straggling. Intensity losses may also occur as a result of the induced angular spread and might become quite severe in cases where the constituents of the molecule have comparable mass. In the absence of charge state selection in the terminal, a light unwanted ion accompanied by a heavy ion might acquire a sufficiently large angular spread that most of it dumps in the high energy acceleration tube leading to excessive loading. Most of these problems can be alleviated by using a relatively low gas flow stripper located before the carbon stripper foil