A new method for measuring the absolute efficiency of isotope separation on-line systems

A new method for measuring the absolute efficiency of Isotope Separation On-Line (ISOL) systems is described. The overall efficiency is deduced from the ratio between the rate of the radioactive beam detected after analysis and the rate of incident radioactive beam in the target. It is shown that the unfolding of the different efficiencies, i.e., diffusion, effusion, ionisation and transport allows us to deduce the diffusion constants when the absolute efficiency data is obtained as a function of the target temperature. Using this technique we extracted the fundamental Arrhenius constants for diffusion of Ar and Ne in Carbon targets used in the SIRa experiments at GANIL.