The 14UD heavy ion accelerator

The accelerator is a variant of the Van de Graaff type tandem accelerator in which ions of the required beam, produced initially as negative ions with an additional electron attached to the neutral atom, are accelerated toward a positive high voltage terminal. Passage through a stripper medium of gas or foil removes two or more electrons to produce positive ions. As a result, the positive ions are further accelerated by repulsion from the terminal so that double or tandem acceleration is achieved with a single high voltage terminal. Since the 14UD is rated for a terminal voltage of 14 MV, 28 MeV protons are obtained or with heavier ions, such as 35Cl, for which stripping at the terminal produces useful intensities of ions with charge states of 10+, 11+ and l2+, energies of 182 MeV result for the highest charge state beam. (author)