Self-attraction mapping and an update on local gravitational acceleration measurement in BIPM Kibble balance

Abstract

The self-attraction effect needs to be evaluated and corrected towards a 10 −9 level absolute determination of the local gravitational acceleration g in Kibble balance experiments. In this paper, the self-attraction effect of the BIPM Kibble balance apparatus is modelled by linking the gravitational field to the electrical field based on an electrostatic finite element analysis. A mapping of the gravitational field with different construction segments of the apparatus is presented, yielding a total correction of ( ) ± µ 4.7 0.5 Gal at the mean trajectory position. Experimental measurements are carried out to check the self-attraction model. Based on the obtained result and previous measurements, we updated the g determination along the measurement trajectory for the forthcoming Planck constant measurement.

The BIPM Kibble balance for realizing the kilogram definition

“…The second measurement was carried out with the METAS FG5-X absolute gravimeter in mid-September 2019. The value is corrected for the spatial gradient and the self-attraction of the experiment to calculate the gravity at the location of the artefact on the weighing pan [14]. The instantaneous free-fall acceleration during Kibble balance measurement is obtained by taking into account temporal variation due to earth tides, polar motion and atmospheric pressure.…”

The determination of gravitational acceleration in the joule balance at NIM

“…The self-attraction effects of the joule balance apparatus were calculated based on the method in [19]. By linking the gravitational field to the electrical field, electrostatic finite element analysis (FEA) can be used to model the joule balance apparatus.…”