Mutual Recognition Arrangement Research Articles

CIPM MRA support for hydrogen metrology – A case study

The CIPM Mutual Recognition Arrangement (CIPMMRA) provides one of the most profound frameworks for internationally recognized metrological traceability to the international system of units (SI). National Metrology Institutes demonstrate the international equivalence of their measurement standards and the calibration and measurement certificates they issue through the CIPMMRA. CIPMMRA activities comprise the organization and evaluation of key and supplementary comparisons (KCs/SCs) and the declaration of calibration and measurement capabilities (CMCs) in the BIPM key comparison database (KCDB). In this contribution we showcase up-to-date CIPMMRA activities that could be used in support of hydrogen as a future option for the diversification of energy sources. Relevant metrology areas are chemistry and biology, thermometry, mass, and length. There are already 3 KCs in progress within the CIPMMRA that are directly related to the hydrogen topic and a number of earlier KCs/SCs on other relavant quantities. Todate, the KCDB contains CMCs published by National Metrology Institutes which are dealing exactly with hydrogen as the analyte or which relate to measurement capabilities that are relevant in the context of hydrogen as future energy source.

Subsequent bilateral key comparison study - organic solvent calibration solution - gravimetric preparation and value assignment of aflatoxin B1 (AfB1) in acetonitrile (ACN)

Main textThe original CCQM-K154.b comparison was coordinated by the Bureau International des Poids et Mesures (BIPM) and the Chinese National Institute of Metrology (NIM) on behalf of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) for National Measurement Institutes (NMIs) and Designated Institutes (DIs) which provide measurement services in organic analysis under the 'Comité International des Poids et Mesures' Mutual Recognition Arrangement (CIPM MRA) and/or have participated in the BIPM's Mycotoxin Metrology Capacity Building and Knowledge Transfer (MMCBKT) project as part of its "Metrology for Safe Food and Feed in Developing Economies" Capacity Building Programme.Gravimetrically-prepared solutions having an assigned mass fraction of specified organic analytes are routinely used to calibrate measurement processes for the quantification of the same analytes in matrix samples. Appropriate assignments of the property value and associated uncertainty of calibration solutions thus underpin the traceability of routine analysis and are critical for accurate measurements. Evidence of successful participation in relevant international comparisons is needed to document calibration and measurement capability claims (CMCs) made by national metrology institutes and designated institutes. In total, eleven NMIs/DIs participated in the Track C, Model II, Key Comparison CCQM-K154.b [Gravimetric preparation and value assignment of aflatoxin B1 (AfB1) in acetonitrile (ACN)] for emerging areas of global interest and innovation. Participants were requested to gravimetrically prepare calibration solutions and value assign the mass fractions, expressed in mg/kg, of aflatoxin B1 (AfB1) in the acetonitrile (ACN) solution. Study samples, with assigned values and associated uncertainties were prepared by the comparison participants and sent to the coordinating laboratory for comparison. The Key Comparison Reference Values (KCRVs), calculated form values measured by the coordinating laboratory based on calibrations obtained from independent gravimetrically prepared calibrant solutions, agreed with participants reported values, within their stated uncertainties.AfB1 was selected to be representative of polar aflatoxins. Aflatoxins are a class of mycotoxins generally produced by fungi of the genus Aspergillus. It was anticipated to provide a challenge representative for the gravimetrical preparation and value assignment of calibration solutions in the mass fraction range of 2 mg/kg to 50 mg/kg of mycotoxins with broadly similar structural characteristics.In the original study CCQM-K154.b, nine participants of the MMCBKT programme were provided with a stock solution having a known AfB1 mass fraction and expanded uncertainty to use to gravimetrically prepare and value assign a calibration solution. Three NMIs/DIs also participated using their own calibration solutions. The use of in-house solutions required anadditional capacity to undertake a fit-for-purpose purity assessment. NIM was the only NMI participating using both the MMCBKT based and their own in-house assigned solutions in order to connect the two different groups.It was decided to propose separate KCRVs for each of the two ampoules provided by the participating NMIs/DIs based on the AfB1 mass fraction. This allowed participants to demonstrate the efficacy of their implementation of the approaches used to gravimetrically prepare calibrations solutions and to assess the AfB1 mass fraction.The majority of the AfB1 mass fraction KCRVs (wKCRV) for CCQM-K154.b spanned a mass fraction range of 2.02 mg/kg to 31.57 mg/kg. The relative expanded uncertainties U(wKCRV) ranged from 0.69 % to 2.93 %. Inspection of the degree of equivalence plots for the AfB1 mass fraction assignments in CCQM-K154.b indicated that there was an excellent agreement of results. Solely, the AfB1 mass fraction assignments of the INRAP (Institut National de Recherche et d'Analyse Physico-Chimique, Tunisia) did not agree with the KCRVs. It was found that the samples were altered as a result of an acid contamination.The INRAP has produced a new batch of AfB1 calibration solution using the AfB1 stock solution originally provided to MMCBKT participants to be able to demonstrate the efficacy of their implementation of the approaches used to gravimetrically prepare calibrations solutions and to assess the AfB1 mass fraction. The BIPM organized the present subsequent bilateral comparison CCQM-K154.b.1 to assess the new batch of AfB1 calibration solution of the INRAP. Inspection of the degree of equivalence plots for the AfB1 mass fraction assignments indicated that there is an excellent agreement of the INRAP results for CCQM-K154.b.1.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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report on EURAMET key comparison EURAMET.M.D-K2.2 (1523)

Main textThe key comparison EURAMET.M.D-K2.2 (1523)on the density of liquids determined by oscillation type density meters was organized and carried out within the framework of the EMPIR project 17RPT02 "rhoLiq". Density measurements of liquids are mainly performed by laboratories calibrating or checking liquid density measuring instruments such as oscillation-type density meters. Another aim of this comparison was to establish traceability for liquid density measurements at emerging National Metrology Institutes (NMIs) to enable them to provide high-level measurement and calibration services for national stakeholders, e.g. food, chemical, pharmaceutical and petroleum industries. The results of this comparison can be used to claim calibration and measurement capabilities (CMCs).Most European emerging NMIs in this project had not yet participated in comparisons or obtained unsatisfactory results, or the uncertainty had an unfit magnitude for purpose.BEV (Austria) piloted this comparison, supported by PTB (Germany).Samples of deuterated water, tetrachloroethylene and oil of high viscosity were measured in the temperature range from 5 °C to 20 °C at atmospheric pressure by hydrostatic weighing for this comparison.The coronavirus pandemic caused delays in the proposed initial schedule of this key comparison. Measurements were performed in 2021. The reference values of the key comparison were linked to CCM.D-K2 for PTB and EURAMET.M.D-K2 for BEV.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).

Final report, ongoing key comparison BIPM.QM-K1, ozone at ambient level, comparison with NMC-A*STAR, July 2022

Main textAs part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of Singapore maintained by the National Metrology Centre, A*STAR (NMC, A*STAR) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM), via a transfer standard maintained by the National Institute of Standards and Technology (NIST). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report for SIM.QM-S12: supplementary comparison for trace elements in natural water

Main textThe SIM Supplementary Comparison SIM.QM-S12 for Trace Elements in Natural Water was undertaken to assess and demonstrate the analytical capabilities of national metrology institutes (NMIs) and designated institutes (DIs) of SIM members (or other regions) for the accurate determination of trace elements in natural water at µg/kg levels.Evidence of successful participation in formal, relevant international comparisons is needed to document calibration and measurement capability claims (CMCs) made by NMIs and DIs.Seventeen NMIs and DIs participated. Participants were requested to evaluate the mass fractions, expressed in µg/kg, of arsenic, cadmium, lead and antimony in a natural mineral groundwater that was spiked with the respective elements. A variety of instrumental techniques including inductively coupled plasma mass spectrometry (ICP-MS), isotope dilution ICP-MS (ID-ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), electrothermal atomic absorption spectrometry (ETAAS) and hydride generation flame atomic absorption spectrometry (HG-FAAS) were used by the participants for the determination.The NIST decision tree was used to assign the SCRV estimate for the proposed measurands and to calculate the degrees of equivalence of each national measurement standard following the IAWG Guidance on Using NIST Decision Tree for Comparison Reporting from 30 June 2023.Successful participation in SIM.QM-S12 demonstrates measurement for determination of elements in water matrices. Considering the IAWG Core Capability Matrix, this material falls into the matrix challenge called "Water/aqueous", which corresponds to the CCQM amount-of-substance category fresh water, and so will support CMCs for the metalloids and semi-metals at mass fraction levels below 50 µg/kg (As and Sb measurements) and transition elements at mass fraction levels below 50 µg/kg (except Hg) (for Cd and Pb measurements).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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Report of subsequent key comparison CCQM - K73.2018.2 amount content of H+ in hydrochloric acid (0.1 mol/kg-1)

Main textThe subsequent key comparison K73.2018.2 was performed to demonstrate the capability of the participating institutes to measure the amount content of H+ in hydrochloric acid as a follow-up of the previous key comparison CCQM-K73.2018. A HCl solution of a slightly different composition to that in CCQM-K73.2018 was used.There were two institutes and SMU as the coordinating laboratory participating in this subsequent comparison. UkrCSM obtained results in good agreement with the reference value; INMETRO results exhibited a large bias due to a calculation error found only after disclosure of the results.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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The CCL-K11 ongoing key comparison. Final report for 2023

Main textSix lasers from six national metrological institutes (NMIs) were compared in the year 2023 as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comité Consultative des Longueurs (CCL) in 2007. The absolute frequency of theses lasers was measured in three different node laboratories following the technical protocol for CCL-K11. All are practical realisations of the definition of the metre according to the MeP for the definition of the metre.Five standards are He-Ne-lasers stabilized on the f component of the R(127) 11-5 transitions of molecular iodine 127I2 with a wavelength of approximately 633 nm.The sixth standard is a fibre laser stabilized to the P(16) (ν1+ν3) transition of molecular acetylene 13C2H2 with a wavelength of approximately 1542 nm. The technical protocol was deliberately designed to accommodate artefacts of different wavelengths in a common framework.The results of these measurements are compiled in the present report. The comparison reports, as communicated by each participant, are included in the main document.This document constitutes the thirteenth final report for the ongoing key comparison CCL-K11.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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Bilateral comparison of 1.018 V and 10 V standards between INRIM (Italy) and the BIPM, November to December 2023 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)

Main textAs part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the INRIM (Italy), from November to December 2023. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_7 (Z7) and BIPM_9 (Z9), were transported by freight to the INRIM and back to the BIPM. In order to keep the Zeners powered during their transportation phase, two additional external batteries were connected in parallel to the internal battery. At the INRIM and the BIPM, the reference standard for DC voltage is a Programmable Josephson Voltage Standard (PJVS). The output electromotive force (EMF) of each travelling standard was measured by direct comparison with the primary standard. The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by the INRIM, at the level of 1.018 V and 10 V, at the INRIM, UINRIM, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 1st of December 2023.UINRIM - UBIPM = 0.06 V; uc = 0.05 V, at 1.018 VUINRIM - UBIPM = 0.22 V; uc = 0.12 V, at 10 Vwhere uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the realisation of the volt at the BIPM and at the INRIM, and the uncertainty related to 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 CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of liquid density measurements among SIM NMIs - SIM.M.D-S7

Main textThe aim of this comparison was to compare measurement results on liquid density at 20°C and at atmospheric pressure among National Metrology Institutes (NMIs) belonging to the Inter-American Metrology System (SIM, by its acronym in Spanish).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).

Final report, ongoing key comparison BIPM.QM-K1, ozone at ambient level, comparison with NIM, Oct 2023

Main textAs part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of China maintained by the National Institute of Metrology (NIM) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount fraction range of 0 nmol mol−1 to 500 nmol mol−1.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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

PAWG pilot study on quantification of total haemoglobin in blood

Main textUnder the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P201, was organised. Five National Metrology Institutes (NMIs) participated in this pilot study and provided a total of eleven measurement results using six different methods based on three different measurement principles. The purpose of this pilot study was to develop measurement capabilities for the accurate quantification of intact haemoglobin (Hb) whereby measurement results could be made directly traceable to the SI. The choice of protein resulted from its ability to be quantified via different measurement principles providing different routes of traceability. Hb also provided a model of an intact protein with a complex tetrameric structure which is often measured via quantification of a specific subunit or the incorporated haem group. To achieve appropriate results for the chosen measurand, it was necessary to distinguish between the whole protein and fragments of the tetrameric structure, such as dimers or monomers. The participants were encouraged to investigate several of the measurement methods available. This was considered particularly advantageous in this instance as various methods applied to the same analyte may assist in identifying possible previously unknown biases or interferences of the various methods. Hb is being used as a model system to build capacity in methods for the quantification of proteins with a molar mass ≤ 100 kDa in biological fluids in a concentration range > 1∙106 pmol/g.This was the first pilot study for the quantification of an inherent protein in blood with all the natural variations that protein shows in a clinical sample. The different methods applied by the participants included isotopic dilution (ID) organic mass spectrometry (MS) of specific peptides after tryptic digestion, species-specific ID inductively coupled plasma mass spectrometry (ICP-MS), post-column ID ICP-MS, quantification via total iron after chromatographic isolation of Hb and acid digestion as well as two optical methods. One of the latter was the reference method proposed by the International Committee for Standardisation in Haematology (ICSH) based on the conversion of Hb to hemiglobincyanide (HiCN), the other used the conversion of Hb with alkaline haematin detergent both followed by the measurement of spectroscopic absorbance.Considering the use of very different measurement techniques for the quantification of total Hb, the results are in good agreement with a reference value with corresponding expanded uncertainty of (120.6 ± 1.2) mg/g calculated as DerSimonian-Laird mean. However, the observed differences between the results are not completely reflected in the reported measurement uncertainties. The calculated interlaboratory standard deviation or Tau value (dark uncertainty) was approximately 3 % whilst the average reported measurement uncertainty was approximately half this (1.4 %). A possible reason for this large difference may lie in the underestimation of any necessary conversion factors and their uncertainty contributions, between the target analyte measured and the requested measurand.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 CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Zn-65 of activity measurements of the radionuclide 65Zn to include the 2015 result of the LNMRI-IRD (Brazil) and the 2018 result of the LNE-LNHB (France)

Main textSince 1977, 19 laboratories have submitted 22 samples of 65Zn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Zn-65. The LNMRI-IRD (Brazil) and the LNE-LNHB (France) are the latest participants in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

International comparison of measurements of neutron source emission rate (2016-2021) - CCRI(III)-K9.Cf.2016

Main textSection III (neutron measurements) of the Comité Consultatif des Rayonnements Ionisants, CCRI, conducted a comparison of primary measurements of the neutron emission rate of a 252Cf radionuclide source. A single 252Cf source was circulated to all participants between 2016 and 2020. Ten laboratories participated -CMI (Czech Republic), KRISS (Republic of Korea), IRD/LNMRI (Brazil), LNE-LNHB (France), NIM (China), NIST (USA), NMIJ (Japan), NPL (UK), NRC (Canada) and VNIIM (Russia) - with NPL making their measurements at the start and repeating them at the end of the exercise to verify the 250Cf content of the source. Each laboratory reported the emission rate into 4π sr together with a detailed uncertainty budget. All participants used the manganese bath technique except NMIJ who used a relative method based on measurements with a 3He detector in a graphite pile. VNIIM also made measurements using an associated particle technique. CMI, KRISS, LNE-LNHB, NIM, NPL and VNIIM also measured the anisotropy of the source although this did not formally form part 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 CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

CCEM key comparison CCEM.RF-K26. Attenuation at 18 GHz, 26.5 GHz and 40 GHz using a step attenuator. Final report of the pilot laboratory

Main textThis report summarizes the results of the Key Comparison CCEM.RF-K26 Attenuation at 18 GHz, 26.5 GHz and 40 GHz using a step attenuator which has been performed from January 2015 to February 2018. Fourteen National Metrology Institutes (NMIs) participated in this key comparison, including the National Metrology Institute of Japan (NMIJ/AIST, Japan) which served as pilot laboratory, the National Institute of Metrology (NIM, China), the Physikalisch-Technische Bundesanstal (PTB, Germany), the Laboratoire national de métrologie et d'essais (LNE, France), the Swiss Federal Office for Metrology and Accreditation (METAS, Switzerland), the National Physical Laboratory of India (NPLI, India), the All-Russian Scientific Research Institute of Physico-Technical Measurements (VNIIFTRI, Russia), the Korea Research Institute of Standard and Science (KRISS, South Korea), the National Physical Laboratory (NPL, United Kingdom), the National Metrology Institute of South Africa (NMISA, South Africa), the Tubitak Ulusal Metrologi Enstitűsű (TUBITAK-UME, Turkey), the National Metrology Centre (NMC-A*STAR, Singapore), the Czech Metrology Institute (CMI, Czech Republic) and the Instituto Nacional de Tecnica Aeroespacial (INTA, Spain). The Key Comparison Reference Values (KCRVs) were determined from the measurement results of five to ten participating NMIs, depending on the attenuation and frequency.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 CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Bilateral comparison of 1.018 V and 10 V standards between SASO-NMCC (Saudi Arabia) and the BIPM, September to November 2023 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)

Main textAs part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the SASO-NMCC (Saudi Arabia), from September to November 2023. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_E (ZE) and BIPM_F (ZF), were transported by freight to the SASO-NMCC and back to the BIPM. In order to keep the Zeners powered during their transportation phase, a voltage stabiliser developed by the BIPM was connected in parallel to the internal battery. At the SASO-NMCC and the BIPM, the reference standard for DC voltage is a Programmable Josephson Voltage Standard (PJVS). The output electromotive force (EMF) of each travelling standard was measured by direct comparison with the primary standard. The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by the SASO-NMCC, at the level of 1.018 V and 10 V, at the SASO-NMCC, USASO-NMCC, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 30th of September 2023.USASO-NMCC - UBIPM = 0.06 V; uc = 0.05 V, at 1.018 VUSASO-NMCC - UBIPM = 0.22 V; uc = 0.12 V, at 10 Vwhere uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the realisation of the volt at the BIPM and at the SASO-NMCC, and the uncertainty related to 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 CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Key comparison BIPM.RI(I)-K5 of the air-kerma standards of the BEV, Austria and the BIPM in 137Cs gamma radiation

Main textA new comparison of the standards for air kerma of the Bundesamt für Eich- und Vermessungswesen (BEV), Austria, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137Cs radiation beam using the radiation protection facility of the International Atomic Energy Agency (IAEA) in Seibersdof, Austria in April 2023. The comparison was done using the BEV and the BIPM primary standards and a transfer instrument belonging to the BEV. The direct comparison result, evaluated as a ratio of the BEV and the BIPM standards for air kerma, is 1.0043 with a combined standard uncertainty of 2.7 parts in 103. The result for the indirect comparison is in agreement with the direct result at the level of 3 parts in 104. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database, to update the 2009 comparison result.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 CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Euramet RMO supplementary comparison low pressure air flow between 25m3/h and 400 m3/h

Main textThe purpose of this Supplementary Comparison (SC) for "Low Pressure Air Flow" measurement is to support the Calibration and Measurement Capabilities (CMC) of the participating National Metrology Institutes and Designated Institutes according to CIPM MRA-G-13. The outcome of this comparison should lead to 'a clear and unequivocal' comparison of measurement results between participants.The comparison was performed over the span of one year which started in March 2021 with the determination of the volume flow rate error of the test artifact by VSL. The test artifact was shipped to each participant where they also determined the volume flow rate error in turn. At the completion by all participants, the artifact was shipped back to VSL for a final calibration to show the stability of the artifact.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).

Supplementary comparison SIM.M.FF-S9.2016 for water flow measurement

Main textThe objective of the Supplementary Comparison (SC) SIM.M.FF-S9 for water flow measurement was to support and prove the Calibration and Measurement Capabilities (CMC) of the participating NMIs of Chile (CISA), Peru (INACAL), Bolivia (IBMETRO) and Argentina (INTI). As pilot laboratories, the national metrology institutes of Germany (PTB) and CENAM (Mexico) supported the comparison with reference values. The comparison was organized as a single round robin, started in January 2016 at PTB and finished in August 2019, also at PTB. A combined setup of a turbine meter and Coriolis meter was used as a transfer standard. The nominal calibration conditions of the SC were defined in the flow range between 10 m3/h and 130 m3/h, 20 °C fluid temperature and 0.3 MPa line pressure. In order to estimate the uncertainties u TS, both transfer meters were subjected to extensive characterization measurements at pilot laboratory PTB. The following parameters were researched in detail: fluid temperature, line pressure, reproducibility, flow stability and meter sensitivity to different inflow conditions. The E N values for the turbine meter were calculated based on PTB data, only. The E N values for the Coriolis meter are partly linked to Key Comparison CCM.FF-K1.2015 and were calculated using a common reference value of PTB and CENAM data. The uncertainty of turbine meter u TS was clearly dominated by the sensitivity to disturbed inflow conditions which leads to large values of u TS with > 0.20 %. Beside one calibration, all labs passed the E N criteria of ≤ 1.20. But, due to large values of u TS, the calibrations for all labs were evaluated as inconclusive. The evaluation criteria u comp/u base exceeded the critical value of 2.00 for all calibrations. Finally, the turbine meter was not suitable for a confirmation of the submitted CMC values. The calibration results of the Coriolis meter were characterized by a strong dependency on zero setting. The observed effect was adjusted for the data of both reference laboratories by introducing a new method for autozero correction. Maximum uncertainty values for Coriolis u TS were estimated with 0.069 % at low flowrates and 0.033 % at high flowrates. Besides two calibrations, all laboratories complied with the E N criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria u comp/u base exceeded the critical value of 2.00 at one calibration, only. In consequence, the calibrations by using the Coriolis meter were suitable for a confirmation of the submitted CMC values. In summary, the comparison was successfully finished for a confirmation of the submitted CMC values, related to mass calibrations. For volume related CMCs this comparison was not suitable.The comparison was partially financially supported by the German Federal Ministry for Economic Cooperation and Development (BMZ) - PNs: 2012.2296.7-95259, 2015.2037.8-95306 and 2017.2073.9-95328.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).

Update of the BIPM comparison BIPM.RI(II)-K1.Cr-51 of activity measurements of the radionuclide 51Cr to include the 2012 result of the KRISS (Rep. of Korea), the 2022 result of the POLATOM (Poland), and to link the 2022 EURAMET.RI(II)-K2.Cr-51 comparison

Main textTwo new participations in the BIPM.RI(II)-K1.Cr-51 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the EURAMET.RI(II)-K2.Cr-51 comparison piloted by the POLATOM in 2022, who sent an ampoule from the EURAMET comparison to the International Reference System (SIR). The LNE-LNHB (France) used the EURAMET comparison to update its degree of equivalence. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.Cr-51, and the linked EURAMET.RI(II)-K2.Cr-51. A graphical presentation is also given.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 CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Update of the BIPM comparison BIPM.RI(II)-K1.Ge-68 of activity measurements of the radionuclide 68Ge to include the 2021 result of the NIM (China)

Main textSince 2013, 6 laboratories have submitted 7 samples of 68Ge to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ge-68. Recently, the NIM (China) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalencebetween each equivalent activity measured in the SIR or linked to the SIR from the CCRI(II)-K2.Ge-68 comparison and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.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 CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).