Vertical displacement determination of a levitated superconducting mass

Abstract

The determination of the vertical displacement of the center of gravity of a levitated superconducting body in the National Research Laboratory of Metrology (NRLM) superconducting magnetic levitation project, which is aimed at establishing a new definition of the unit of mass based on the fundamental constants, is discussed. The translation displacement (three degrees of freedom) and the attitude change (three degrees of freedom) of the measuring point, which is the optical center of the cube corner prism O/sub C/ of the floating body, are measured using a newly developed optical measuring system. To determine the vertical displacement of the center of gravity of the floating body G/sub C/ the relative position of G/sub C/ with respect to O/sub C/ is required, which is determined using the energy relation between the electromagnetic energy and the gravitational potential energy under levitating conditions.