Jorge C. Torres-Guzmán, Luis A. Santander-Romero, Luiz H. Paraguassú, Paulo R. G. Couto, Ilca L. Bezerra
SIM VACUUM COMPARISON FROM 13 Pa UP TO 1,33 kPa
This comparison constitutes the first vacuum comparison among National Metrology Institutes (NMI) within the Interamerican Metrology System (SIM). Each laboratory used its national standards. The Centro Nacional de Metrología (CENAM, Mexico) used a primary standard (static expansion system type) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO, Brazil) used a secondary standard (comparison system type). CENAM had the role of coordinator and pilot laboratory. The comparison started in December 2004 and finished in March 2005. The objective of the comparison was to estimate the level of agreement for the realization of the quantity and the uncertainty associated to its measurement.
One transducer (Capacitive Diaphragm Gauge) was used as transfer standard; the comparison range was selected from 13 Pa to 1,33 kPa. The relevant aspects of the measurement protocol are summarized in the paper but were widely developed in the comparison reference documents. The gas used for the comparison was nitrogen. The measurements started at the lowest pressure and the pressure was increased up to the maximum range. The analysis of measurements comparability between the laboratories is included here. This bilateral comparison has been entered within the SIM data base as a pilot comparison SIM.7.26 P.