The continuous expansion method is applied to reference standards of absolute pressure with the aim of improving traceability and reducing uncertainty in the range 1 × 10-6 Pa to 1 × 10-3 Pa. It is a realistic goal to reduce the relative uncertainty by a factor of two down to 2.5% (k = 2). This article describes a study of the method carried out at LNE-LCM. It includes a detailed uncertainty budget.

Key words

continuous expansion
fluxmètre gazeux à pression constante
constant pressure flowmeter