Current status of the PB2 Planck-Balance

Abstract

The Planck-Balance (PB) is a table-top Kibble balance that was developed in a cooperation between the Physikalisch-Technische Bundesanstalt (PTB) and the Technische Universität Ilmenau (TUIL). The PB2 version of this system aims for a mass range from 1 mg to 100 g with uncertainties corresponding to class E2 mass standards as described in OIML-R111. In order to reduce the costs of the system, it is mostly set up by using commercially available standard parts and operates in air. A modified EMFC load cell is used to guide and drive the coil that is utilized in the Kibble experiment, while a homodyne interferometer system measures the displacement of the coil. The induced voltage is measured by a calibrated digital multimeter, which is also used to measure the voltage drop caused by the compensation current that is necessary to balance the system when a weight under test is applied. The paper presents the main components of the system while evaluating the different uncertainty contributions to the calibration of a mass standard. Recent experiments are presented that show the possibilities of a direct implementation of the new kilogram definition on the uncertainty level of class E2 mass standards.