Absolute gravity measurements at Ulusal Metroloji Enstitüsü

Abstract

Acceleration of gravity, g value is widely used for research purposes in many areas such as geology and geography. Absolute determination of g plays an important role in metrology in calibrations of mechanical force standards, pressure transducers and load cells. An also current trend in mass metrology demonstrates that new mass standards based on electrical references for redefinition of kilogram are under development. This device would balance the force of a current (as determined by the quantum Hall effect and the Josephson junction effect) against the weight of a test mass. This application requires knowledge of the absolute value of g at parts in $10^9$. The gravity datum and the gravity scale in a given geographical area play the role of a metrological standard for geodetic and geophysical applications. For those reasons an absolute gravimeter system was bought at UME from Micro-g Lacoste/USA. It is a portable device so that it can also be used outdoor measurements. Uncertainty in g measurements is at the level 10 $\mu Gal$. Acceleration of gravity g, value was measured in force, pressure, torque, mass and vibration laboratories in order to have more accurate measurements at UME. The reproducibility and repeatability measurements have been carried out at Vibration Laboratory. A brief summary about absolute gravimeter and performed gravimetry measurements are presented in this paper.