Traceability of acoustics and vibrations standards at the National Center of Metrology in Mexico

Abstract

After the creation of the Mexican Primary Laboratory of Metrology, primary standards on acoustics and vibrations are being established for the first time in the country. For this task, CENAM staff has relied on the technical assistance of the corresponding groups at NIST and NRC. The process has involved several specific features due mainly to the particular needs and conditions of the Mexican laboratory. On the acoustics side, for the instrumentation of the reciprocity method for microphone calibration, the altitude of the site at which CENAM is located and the consequent low pressure lead to the proposal for a pressure-controlled chamber. Both the proposal and its completion has been carried out at NIST, with direction of its staff and participation of CENAM staff. The stage in which the project is at the moment will be shown. Also the instrumentation and methods used for giving traceability from CENAM to transfer and working standards of external customers. On the vibrations side, instrumentation of the reciprocity method for accelerometer calibration has been achieved with the Bouche Labs 5000CR system. Besides an interferometric system is being obtained as a complementary aid and for cross checking purposes. Traceability to transfer and working standards at CENAM is already being accomplished through the comparison method. An evaluation of the systems performance will be presented and a first estimation of their uncertainties will be discussed.