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[en] An experiment is described for determining the atomic mass constant by accumulating ions from an ion beam up to a weighable mass. It establishes a link between the international prototype of the kilogram, the realization of the associated SI unit and an atomic mass. The items necessary for such an experiment are a high-current ion source, an ion optical system with high transmission, a suitable ion collector and a vacuum balance. With the most recent measurement, a mass of more than 320 mg of bismuth was accumulated and its atomic mass was determined with a relative standard uncertainty of 9.4 * 10-5. Special emphasis is placed on determining the mass loss of the accumulated ions caused through sputter effects in the ion collector. Although work on this experiment at the PTB has now been stopped, we conclude with a number of suggestions that could lead to much smaller relative uncertainty in a future experiment. (authors)
[en] A calculation of the vacuum-polarization contribution to the hyperfine splitting for hydrogenlike atoms is presented. The extended nuclear charge distribution is taken into account. For the experimentally interesting case 209Bi82+ we predict a Δλ=-1.6 nm shift for the transition wavelength of the ground-state hyperfine splitting
[en] The same sample of CR-39(DOP) polymeric foil has been exposed to 209Bi (11.4 MeV/u) ions at three different angles (30o, 45o and 60o) of incidence. The exposed sample has been etched chemically and various parameters of the etched tracks have been measured. The objective of the present study is to establish the isotropic etching behavior of CR-39(DOP) polymer.