Centro Nacional De Metrologia Research Articles

Final report of AFRIMETS.M.D-S4 - hydrometer calibrations

Main textA supplementary comparison for hydrometer calibration using Cuckow's method was proposed during the 10th AFRIMETS Committee for Mass and Related Quantities (TCM) meeting held at the National Institute of Standards (NIS, Egypt). Two laboratories only from AFRIMETS, NIS and the National Metrology Institute of South Africa (NMISA), had the capacity to participate in the comparison. Generously, Centro Nacional de Metrologia (CENAM, Mexico) accepted to participate in the comparison and provided reference values. This comparison, designated as AFRIMETS.M.D-S4, was coordinated by the NIS supported by all participants. The corrections to be applied to three stated scale readings at 20 °C of different transfer standards in the density range between 0.600 g/cm3 to 1.300 g/cm3 were determined. NIS carried out the measurement at the beginning and at the end of the comparison.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 https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

SIM.M.T-S2 supplementary bilateral comparison calibration of a reference torque wrench final report

A Regional Metrology Organization (RMO) key comparison on the calibration of a reference torque wrench was carried out between the Centro Nacional de Metrologia (CENAM, Mexico) and the Instituto Nacional de Metrologia (INM, Colombia), between September 2017 and October 2017. The results of this comparison are reported here, along with descriptions of torque standards used by CENAM and INM, and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyse, determining the degree of equivalence between the torque measurements from CENAM and INM.Main textTo 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 (CIPM MRA).

Pneumatic gauge pressure comparison from 700 kPa to 7 000 kPa

This report presents the final results of the supplementary comparison SIM.M.P-S10 for pneumatic gauge pressure from 700 kPa to 7 000 kPa. This comparison was carried out in the period from November 2014 to January 2015, by using a digital pressure manometer with uncertainty 0.010 % of the reading as the transfer standard for the comparison. The reference value for this comparison was given by the Centro Nacional de Metrologia de Mexico (CENAM, Mexico).Main textTo 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 (CIPM MRA).

Characterization of a Type-N Coaxial Microcalorimeter for Use as Microwave Power Standard at CENAM

This paper describes the metrological characterization of a new type-N coaxial microcalorimeter and its associated thermistor-type transfer standard, which together are used as the primary standard for microwave power from 0.05 to 18 GHz at the Centro Nacional de Metrologia, Queretaro, Mexico. The design characteristics, evaluation method, and measurement uncertainties of the primary standard are given and compared to recent realizations found in the open literature. The metrological characterization of the microcalorimeter is based on a comparison method to indirectly obtain its correction factor. The effective efficiency of the transfer standard, directly calibrated in the microcalorimeter by means of calorimetric measurements, is shown and compared against measurements performed by National Institute of Standards and Technology, showing good agreement within the estimated expanded uncertainties (0.21%–0.47%). The developed data acquisition system to automate the effective efficiency measurements and the proposed software leveling loop to keep the microwave power level constant are also discussed. This approach allows to keep an RF power stability of better than 100 ppm over several hours and is a straightforward solution to replace analog leveling systems which require obsolete hardware. Finally, the analysis followed to evaluate the uncertainty for the effective efficiency measurements is thoroughly described.

Final report of the SIM.QM-S7 supplementary comparison, trace metals in drinking water

SIM.QM-S7 was performed to assess the analytical capabilities of National Metrology Institutes (NMIs) and Designated Institutes (DIs) of SIM members (or other regions) for the accurate determination of trace metals in drinking water. The study was proposed by the coordinating laboratories National Research Council Canada (NRC) and Centro Nacional de Metrologia (CENAM) as an activity of Inorganic Analysis Working Group (IAWG) of Consultative Committee for Amount of Substance - Metrology in Chemistry and Biology (CCQM). Participants included 16 NMIs/DIs from 15 countries. No measurement method was prescribed by the coordinating laboratories. Therefore, NMIs used measurement methods of their choice. However, the majority of NMIs/DIs used ICP-MS.This SIM.QM-S7 Supplementary Comparison provides NMIs/DIs with the needed evidence for CMC claims for trace elements in fresh waters and similar matrices.Main textTo 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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Eutectic Ga-In Melting-Point Blackbody for Radiation Thermometry

The Radiation Thermometry Group at the Centro Nacional de Metrologia (CENAM) is presently working with low-temperature fixed-point blackbodies to study their suitability for calibration and verific...

Bilateral Intercomparison of Spectral Directional Emissivity Measurement Between CENAM and PTB

Both Centro Nacional de Metrologia (CENAM, Mexico) and Physikalisch-Technische Bundesanstalt (PTB, Germany) are national metrology institutes and provide the dissemination of the spectral directional emissivity as a calibration service. CENAM started this service recently. The emissivity measurement capability of PTB took part in two international comparisons performed in the past among other national institutes. The measurement instrumentation and techniques used for emissivity measurements at CENAM and PTB are both based on Fourier transform infrared spectrometers. Both setups are based on the principle of a spectral comparison of the radiances of the sample and blackbody radiator. In detail, the setups differ: CENAM has the capability of measuring the directional spectral emissivity normal to the sample surface, while PTB measures the directional spectral emissivity at angles of observation ranging from \(5^{\circ }\) to \(80^{\circ }\), and provides the hemispherical spectral and total emissivity of samples as well. For this comparison, it was agreed to compare the value of the directional spectral emissivity normal to the sample surface obtained by CENAM with the one determined at an angle of \(5^{\circ }\) by PTB. Four samples of different spectral directional emissivities were measured by the two institutes. For the samples, four copper disks with a diameter of 50 mm and a thickness of 5 mm were used. Three of them were coated with Comex 1402470 (white), 1402471 (aluminum), and 1402474 (black) paints, respectively, and the other one with Nextel 811-21 paint. Measurements were obtained for each sample at a temperature of about \(150\,^{\circ }\)C, and in the spectral range from \(400\,\mathrm{cm}^{-1}\) to \(2500\,\mathrm{cm}^{-1}\) (\(25\,\upmu \mathrm{m}\) to \(4\,\upmu \mathrm{m}\)). The description of the experimental setups used and the comparison results are presented in this paper. It was found that the results obtained at CENAM and at PTB agree well within the declared standard uncertainties.

Bilateral key comparison SIM.T-K6.2 on humidity standards in the dew/frost-point temperature range from -20 °c to 20 °c

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the Centro Nacional de Metrologia (CENAM, Mexico) between July 2008 and December 2008. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and CENAM and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and CENAM.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 CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Electrochemical characterization of a primary electrolytic conductivity cell at CENAM

Linear voltammetry and electrochemical impedance spectroscopy experiments were performed in order to obtain basic information about the electrochemical behavior of the primary cell of electrolytic conductivity at Centro Nacional de Metrologia. Linear voltammetry shows that the amplitude of the sinusoidal perturbation must be smaller than 300 mV. Electrochemical impedance results indicate that optimal frequency interval extends from 5 to 0.6 kHz. Regarding sinusoidal signal amplitude, a lower bias with respect to electrolytic conductivity of an independent reference solution is obtained at 10 mV than at larger amplitudes; in addition, electrode integrity is improved.

Direct Comparison of Josephson Voltage Standards at 10 V Between BIPM and CENAM

A direct comparison of Josephson voltage standards at 10 V between the Bureau International des Poids et Mesures (BIPM) and the Centro Nacional de Metrologia (CENAM), Mexico, was carried out in September 2011. This comparison is part of the BIPM key comparisons (BIPM.EM-K10.b) and took place in the new DC Voltage Laboratory of CENAM. Both systems were very stable during the comparison, and the type “A” uncertainty was very low. The relative voltage difference between the two quantum standards was $-$ 6 parts in $10^{11}$ ( $-$ 0.6 nV), with a combined uncertainty of 7 parts in $10^{11}$ (0.7 nV).

Report to TIM Editor on CPEM 2012

CPEM 2012 is a biennial scientific event devoted to topics related to electromagnetic measurements at the highest accuracy levels. These cover the frequency spectrum from dc through the optical region. A major focus of CPEM is quantum devices that relate electrical standards to fundamental constants and the international system of units. CPEM presenters were encouraged to submit full-length papers on their work to the editors of this special issue devoted to the topic of precision electromagnetic measurements. The 2012 CPEM was held at the Gaylord National Resort at National Harbor just outside of Washington D.C. from 1-6 July 2012. The National Institute of Standards and Technology (NIST) led the Local Organizing Committee and teamed with the NCSL International and Centro Nacional de Metrologia (CENAM) to organize CPEM 2012. CPEM was attended by 396 metrologists, physicists, and engineers from National measurement institutes, industry, and universities. Over 75% of the attendees came from 40 countries outside the U.S. to attend CPEM 2012. It was a pleasure to welcome attendees back to the Washington D.C. area, especially during the national holiday as had been done 14 years earlier at CPEM 1998. The next CPEM will be held in Rio de Janeiro, Brazil, from 24 to 29 August 2014 hosted by the Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro), in cooperation with the Instituto Nacional de Tecnologica Industrial of Argentina.

Development of Primary Frequency Standards at CENAM

The Centro Nacional de Metrologia, CENAM, has developed an optically pumped cesium beam frequency standard, CsOP-1, and is close to completing a cold atom fountain primary clock, CsF-1. Evaluation ...

Validation of the Open-Area Antenna Calibration Site at CENAM

The process of validating an open-area antenna calibration test site (CALTS) as a national reference for Mexico is presented. It is shown that the site is fully compliant with CISPR-16-1-5 (2003-11). The site's performance, according to this standard, is determined by the difference between the measured and theoretical calculated site attenuation (SA) values. The main contributions of this paper are the assessment of the validation process and the practical implications deduced from this assessment process. The assessment validation process was performed using the following: 1) three sets of calculated theoretical SA values; 2) two measurement systems used almost simultaneously to strengthen the validation (one is based on a network analyzer, and the other is based on a spectrum analyzer); and 3) two direct-connection configurations. The similarities among the four sets of obtained results allow the deduction of the following important practical implications: 1) Measurement methods and system are validated, and we have confidence on the results from both measurement systems. 2) The direct connection at baluns is used in practice, because its effects are better canceled experimentally rather than mathematically. 3) There is a need to construct the set of dipoles of the Centro Nacional de Metrologia (CENAM) due to bad functioning of the commercial 700-MHz dipole.

Absolute Frequency Measurement of the R(12) 26-0 and R

A direct phase coherent determination of the absolute frequency of the a15 component in the R(12) 26-0 and b10 component in the R(106) 28-0 transitions in 127I2 at 543 nm has been made at the International Bureau of Weights and Measures. Lasers from the Czech Metrology Institute (Czech Republic), the National Institute of Metrology (China), the Centro Nacional de Metrologia (Mexico), the Standards, Productivity and Innovation Board (Singapore), the Centre for Metrology and Accreditation (Finland), the Danish Institute of Fundamental Metrology (Denmark), the National Physical Laboratory (U.K.), and the International Bureau of Weights and Measures took part. The mean frequency values found are f(a15)=551579856480.4 kHz, uc=4.8 kHz and f(b10)=551580162397.1 kHz, uc=4.6 kHz for the current group of lasers, where uc is the combined standard uncertainty. This constitutes a 30-fold improvement in accuracy for this radiation, which is recommended for the realization of the definition of the meter. If only lasers equipped with an iodine cell temperature control are considered, the group of lasers shows a dispersion of 7 kHz. This value is indicative of the level of reproducibility that can be expected at present for this type of standard

Role of National Metrology Institutes for Comparable Measurements

The global economy and fair trade commitment has forced the need to demonstrate equivalence between national measurement standards. That includes a need to meet ever‐increasing demands for accuracy, range, and diversity of measurements. Recent activities of national metrology institutes (NMIs) are among the topics discussed in this article. These include mutual recognition of calibration and measurement certificates of NMIs under mutual recognition arrangements (MRAs), operated among NMIs under an international framework of five regional metrology organizations (RMOs). Particular attention is given to the efforts of Mexico's NMI, Centro Nacional de Metrologia (CENAM), to establish a national traceable measurement system for sectoral testing laboratories for agriculture. Other initiatives include proficiency testing in collaboration with the Colegio de Posgraduados, the intention being to promote development and certification of reference materials and to establish sectoral reference laboratories in the country.

International comparison of volume measurement standards at 50 l at the CENAM (Mexico), PTB (Germany), Measurement Canada and NIST (USA)

The Centro Nacional de Metrologia (CENAM), the Physikalisch-Technische Bundesanstalt (PTB), Measurement Canada (MC), and the National Institute of Standards and Technology (NIST) maintain the national primary standard facilities for the measurement of volume in Mexico, Germany, Canada and the United States, respectively. These laboratories have compared volume measurements at 50 l. The comparison was accomplished by each laboratory calibrating a transfer standard volume that was circulated among the laboratories, with the CENAM acting as pilot laboratory. All the participants used gravimetric methods. The maximum and minimum reported volumes differ by 0.0098 %.

MESURA 2000: a strategy to integrate a true communication network of metrology experts with process technology experts

The Centro Nacional de Metrologia (CENAM) has developed the MESURA Interinstitutional Network in collaboration with other research and development institutes in Mexico. This network has the aim of providing integral metrological services to industry throughout the country, with uniform standards of quality and consistency. The fulfillment of this aim has been possible because of a number of factors that have made the MESURA Program an attractor for the integration of metrological services. Among these factors are: an unswerving focus on the customer needs, an integral and logical problem solving approach to consultancy, adequate modular classification of the consultants functions, clear-cut definition of the functions of each member of interdisciplinary groups, and a uniform code of communication among the members of the network. The next stage of the strategy is to strengthen the link between metrology and its industrial applications forming a new type of consultant with the technical experts from R&D Centers. These will be consultants with general knowledge and experience in metrology, specialized in certain type of industrial processes and products. The strategy will be initiated in the year 2000 and with it the MESURA Network is expected to make a strong contribution to fostering the optimum use of metrology in industry and to act as a channel for the integration of other technologies in which the participating Centers have expertise.

First year results of the international comparison of UTC(CENAM)

The Centro Nacional de Metrologia (National Center of Metrology), CENAM, in Mexico, has been contributing to UTC since March 1996 with six HP5071A high performance frequency standards. The UTC(CENAM) (or UTC(CNM) as it is labeled in BIPM Circular T) is presently generated from a single HP5071A clock which is operated under controlled temperature and humidity conditions. In this report we present results of the first year (from March 96 to March 97) of international comparison of UTC(CENAM). We use the common-view time transfer technique and follow the BIPM schedule for North-West America to make that comparison through the BIPM. Analysing the BIPM Circular T CENAM's data, we find the fractional frequency instability of our Master Clock to be about 2/spl times/10/sup -15/ for an integration time (/spl tau/) of 81 days, and an intrinsic frequency offset of about 1,5/spl times/10/sup -13/.