Accumulation of decelerated gold ions

As part of our experiment to determine directly the mass of a gold atom in the SI unit kilogram, we have studied the interaction of decelerated gold ions with the surface of a gold coated quartz crystal. The ratio between the change of mass of the gold coated quartz crystal and the total charge of the ion current is measured as a function of the ion energy. The transition between the mass loss, mainly resulting from the sputtering effects, and the mass increase at the oscillator quartz, has been observed. At sufficiently low ion energies the measurements have shown a reasonable agreement with the expected value of the mass of a gold atom in the unit kilogram. Hence, the basic scheme for a direct determination of atomic masses in the SI unit kilogram has been successfully demonstrated