1. LNE-Cnam 1 , 61 Rue du Landy, F93210 La Plaine-Saint Denis, France
2. 2Joint Research Laboratory for Fluid Metrology Evangelista Torricelli Between LNE and INRiM, France and Italy
3. Istituto Nazionale di Ricerca Metrologica (INRiM) 3 , Strada delle Cacce 91, 10135 Torino, Italy