A primary facility for the dynamic preparation of nitrogen dioxide gas standards is being established at the BIPM. The BIPM NO2 facility is used to dynamically generate gravimetric mixtures of NO2/air in the range (1 to 15) µmol/mol.
The facility is based on the constant permeation of NO2 through a fluoropolymer membrane (permeation tube). The mass of the permeation tube is constantly monitored by a magnetic suspension balance. A multiple gas cylinder sampling module is under construction with a capacity of up to 15 cylinders. This system will allow the comparison of NO2/air mixtures in high-pressure cylinders with primary mixtures generated dynamically. The NO2 facility will be used for value assignment and comparison of NO2 gas standards and assessment of their stability.
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Summary
