The New Static Expansion System Of METAS

Christian Wüthrich

Abstract

The METAS static expansion system was built in 2004 and has been extensively characterised during the last two years.<br /> The system consists of four expansion stages allowing the generation of calculable pressures ranging from 5·10^-6 Pa up to 2000 Pa.<br /> Uncertainty calculation yields a relative uncertainty of 0.001 (k=2) for the volumetric ratio of the expansion stage. The relative uncertainty on the pressure obtained after expansion is 0.003 above 10 Pa, it is still 0.01 at 2·10^-4 Pa.<br /> Measurement of the accommodation coefficient of two SRG from 10^-5 Pa up to 0.1 Pa has shown no significant deviation of the accommodation coefficient over the full range of measurement and over a period of time of 18 months.

Keywords

static expansion, pressure, vacuum

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IMEKO-TC16-2007-035u.pdf

DOI

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IMEKO TC

TC16 - Pressure and Vacuum Measurement

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