RESULTS OF BILATERAL COMPARISONS - CAPABILITIES AND PROBLEMS OF SPINNING ROTOR GAUGES

Several rotors were calibrated both at ETL and IMGC in the pressure ra nge from 10(-4) to 100 Pa. The calibrations were performed in argon at mosphere by using a static multi-stage system at the ETL and dynamic a nd static apparatus at IMGC. With stable rotors, the comparison showed that the two laboratories agree within 1%. Two rotors were calibrated also at higher pressures, with the aim of increasing the comparison r ange; for pressure up to 10 Pa there is a maximum increase of the gaug e coefficient of 1%; at this pressure level a comparison is still sign ificant and the results of ETL and IMGC are in good agreement. (C) 199 7 Elsevier Science Ltd.