Final Report on Key Comparison APMP.M.P-K5 in differential pressure from 1 Pa to 5000 Pa

Abstract

This report describes the results of a key comparison of small differential pressure standards at two national metrology institutes (NMIs: NMIJ/AIST and MSL) that was carried out during the period May 2005 to October 2005 within the framework of the Asia-Pacific Metrology Programme (APMP) in order to determine their degrees of equivalence at pressures in the range 1 Pa to 5000 Pa. The differential pressures were compared at a line pressure of about 100 kPa (absolute). The pilot institute was the National Metrology Institute of Japan (NMIJ)/AIST. Both participating institutes used double pressure balances as their primary pressure standards. The transfer standard package consisted of three high-precision pressure transducers: one capacitance diaphragm gauge to provide high resolution at low differential pressures, and two resonant silicon gauges to provide the required calibration stability. The transfer standard was calibrated at the pilot institute (NMIJ/AIST) at the beginning and the end of the comparison. These results show that the transfer standard was sufficiently stable to meet the requirements of the comparison. The degrees of equivalence of the measurement standards were expressed quantitatively by two terms, deviations from the key comparison reference values and pairwise differences of their deviations. The differential pressure standards in the range 1 Pa to 5000 Pa of the two participating NMIs were found to be fully equivalent within their claimed uncertainties. The degrees of equivalence in this comparison were also transferred to the corresponding CCM key comparison, CCM.P-K5, and it is shown that the NMIJ values were equivalent to the CCM KCRV within the claimed uncertainties.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 CIPM Mutual Recognition Arrangement (MRA).