Results of the key comparison SIM-Euromet.M.P-BK3 (bilateral comparison) in the pressure range from 3 × 10^-4 Pa to 0.9 Pa

Abstract

A medium and high vacuum primary standard has newly been set up at the CENAM, Mexico. This vacuum standard is based on the static expansion method and covers a measuring range from 1 × 10-5 Pa to 1 × 103 Pa of absolute pressure.To validate its function and uncertainty budget, in 2002 a comparison was performed with a primary standard of the vacuum metrology section at PTB which had taken part in the key comparison CCM.P-K4. In this manner, the degree of equivalence of the pressure measurements performed with this standard with those of other national primary standards of the CCM.P-K4 could be found. In addition, a link could be achieved with the national standards of the Euromet comparison Euromet.M.P-K1.b, since the latter comparison was carried out with the same protocol and the same tranfer standards, having also PTB as common participant.Two spinning rotor gauges served as transfer standards and showed an excellent transport stability. The effective accommodation coefficients of the rotors had to be determined at eight target points, at and between 3 × 10-4 Pa and 0.9 Pa.The pressures generated by the PTB and the CENAM primary standards showed good agreement within their combined uncertainties. So, there is also equivalence of the CENAM medium and high vacuum primary standard with the other national primary standards of the CCM.P-K4. The CENAM primary standard is also equivalent with the reference value of the Euromet.M.P-K1.b.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the Mutual Recognition Arrangement (MRA).

Realization of the medium and high vacuum primary standard in CENAM, Mexico

“…A comparison between PTB and CENAM was performed with the purpose of identifying possible deviations of the generated pressure in SEE-1 against the internationally validated standard of PTB and of checking the assigned uncertainties of the pressures in SEE-1. This comparison [7] was performed according to the CIPM guidelines and was assigned by SIM-Euromet.M.P-BK3. It links in the whole range (3 × 10 −4 Pa to 0.9 Pa) to the Euromet.M.P-K1.b comparison, where the same transfer standards and the same procedures were used [8].…”