Measurements of the Acceleration due to Gravity at the Gravity Laboratory of the National Institute of Metrological Research Turin (Italy)

The work hereafter described was carried out during the period October-November, 2005 by the National Institute of Metrological Research (INRIM), formerly Institute of Metrology G.Colonnetti (IMGC-CNR), and in June, 2006 by the European Center for Geodynamics and Seismology (ECGS), Luxemburg. The experimental results of the measurement of the acceleration due to gravity carried out at the Gravity Laboratory of INRIM are reported. The estimate of the absolute acceleration due to gravity together with the vertical gradient are reported. The observation site at the Gravity Laboratory of INRIM is available as a reference absolute station for a gravity net. Absolute measurements were performed by INRIM with the new transportable ballistic gravimeter, the IMGC-02. The measurement apparatus and the measurement uncertainty are shortly described. Relative measurements were performed by ECGS with the spring gravimeter Scintrex CG5#008. The measurement traceability is assured because the IMGC-02 adopts length and time standards traceable to the national standards. It participates to the International Comparisons of Absolute Gravimeters (ICAGs) organized by the Bureau International des Poids et Mesures (BIPM) to assure the declared level of uncertainty. The CG5#008 measurement scale is calibrated with another absolute gravimeter, the FG5-216.