Indirect measurements of beam-energy differences for various species of ions extracted from a FEBIAD source

The Chalk River on-line isotope separator is used routinely to measure directly the masses of neutron-deficient nuclides. Because the instrument is momentum-focusing, but not energy-focusing, it is sensitive to small changes in beam energy. In order to explore whether a chemical effect exists leading beams of different elements to emerge from the ion source with different energies, we have done a series of measurements of mass ratios between two isotopes of different elements, the masses of which are known. Any difference between our deduced mass ratio and that found in the literature is interpreted as resulting from a difference in the beam energies. Our technique is sensitive to beam-energy differences at the one-part-per-million level. So far we have not seen any conclusive evidence at this level, for the elements tin, indium, cadmium and silver, that different elements emerge from the ion source with different beam energies. (orig.)