Using an intense bismuth ion beam for the accumulation of a weighable mass of atoms

At the Physikalisch-Technische Bundesanstalt, an experiment for the direct measurement of the atomic mass unit is underway by accumulating ions from an ion beam up to a weighable mass. Until now, an intense bismuth ion beam of /spl ap/5 mA can be extracted out of a cold or hot reflex discharge ion source (CHORDIS). Different arrangements of the beamline ensuring a high transmission will be discussed. Finally, suitable geometries of an ion collector are shown based on SIMION-3D simulations.