Sensitivity Drift Behaviour of Precision Mass Comparator for Weighing Prototype Mass Standards

Abstract

Abstract:The sensitivity of commercially available precision mass comparators used for the calibration of high accuracy stainless steel weights are usually adjusted using either external or internal stainless steel weights. This procedure works well when stainless steel weights are calibrated against stainless steel reference mass standards. When a Pt-Ir prototype mass standard is used as reference standard instead, the buoyancy effect arising from the large difference in the density of the two materials will magnify the error contribution due to the sensitivity characteristics behaviour of the mass comparator, affecting the measurement result and its associated uncertainty. Although the sensitivity can be determined externally through a series of comparative weighings involving the prototype reference, its behaviour is still not well appreciated. A series of experiments are carried out to study this behavior and the influence factors associated with it. The experimental results will be used to identify p...