Comparison between NPL and INRIM in the range 3.10-4 Pa to 9.10-2 Pa

Project Description

The transfer standard package, supplied by PTB, consists of two spinning rotor gauges (SRGs) contained within a novel transportation device.

At NPL, the measurements will be performed on three consecutive days using the series expansion standard SEA2 which is described below. The following target pressures will be used for the calibration: 3·10^-4 Pa, 9·10^-4 Pa, 3·10^-3 Pa,>9·10^-3Pa,2·10^-2 Pa and 9·10^-2 Pa.(2·10^-2 Pa used due to characteristics of NPL static expansion standard).

The INRIM continuous expansion system involved in this comparison is based on the expansion of a pure gas, which is pumped through a fixed conductance.

Comparison measurements at NPL will be performed simultaneously for the two SRGs, each being operated by a MKS SRG2-CE controller with a SH-700 sensing head. The fact that IMGC has only one MKS SRG2-CE control unit will mean complete calibrations of each rotor will have to be performed independently.

Data will be collected and analysed according to the regional key comparison Euromet.M.P-K1.b that was completed between April 2000 and September 2001.

The pilot laboratory NPL expects to complete it’s first set of measurements in July 2005 before sending the transfer standard to IMGC for measurements in late July / August 2005. The comparison loop will be completed at NPL in late August / September 2005.

Final Report 2007-02-28

The comparison has been completed and the report can be downloaded here>>.