ACCELERATION OF AUN CLUSTERS TO MEV ENERGIES

Gold clusters Au, with n less-than-or-equal-to 5 and masses m less-tha n-or-equal-to 985 u have been accelerated to MeV energies with the tan dem accelerators at Orsay and Erlangen. Singly charged negative cluste r ions were obtained from a conventional sputter ion source and accele rated between ground potential at the entrance of the accelerator and the terminal (in the middle) at several MV. In a gas channel positione d in the terminal they lose one or several electrons and become neutra l or positively charged clusters, respectively. The ions are then acce lerated towards the exit of the tandem accelerator. Identification of Au(n)+ clusters is achieved by measuring the time-of-flight of the clu sters.