Design of sorption and buoyancy artefacts made of silicon


  • K. Lehrmann Physikalisch-Technische-Bundesanstalt Braunschweig
  • R. Tutsch Technical University Braunschweig Institute of Production Metrology Braunschweig
  • F. Härtig Physikalisch-Technische-Bundesanstalt Braunschweig



The design of sorption and buoyancy artefacts made of silicon will be shown. With these artefacts, also known as transfer standards, high-precision calibrations can be performed under atmospheric conditions. They are used to systematically determine and correct deviations in air density and deposits on the surface, such as water and hydrocarbons. This development has been of importance since the unit kilogram can be realized by monocrystalline spheres made of isotope enriched silicon in line with the new definition of the SI in 2019. The special constraints and the complete geometric design parameters for sorption and buoyancy artefacts will be presented.