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A comparison measurement between 10 national metrology institutes on two types of depth setting standards was conducted using mostly tactile but also two optical instruments for measurement. Three etched silicon standards with depths of 5, 20 and 50 μm and one diamond turned nickel coated copper standard with depths of 200, 600 and 900 μm were measured. The cross section of the grooves was trapezoidal. Most of the participants confirmed their CMC entries. Since many measurements had to be made, contamination of the standards and heavy wear on the standards were also observed after the comparison was completed. The wear consists of indentation marks from stylus instruments on both types of standards and as many as 70 scratch marks on the nickel coated copper artefact used. This indicates that the contact pressure of the tactile measuring devices used by some partners was too high. This can be caused by a too high probing force or a too small probing tip radius. Thus, for future comparisons the actual probing force and actual tip radius need to be measured during the comparison by the participants to assure that the recommended values (2 μm tip radius and 0.7 mN probing force) are not exceeded. The recently published German standard DIN 32567-3 "Determination of the influence of materials on the optical and tactile dimensional metrology - Part 3: Derivation of correction values for tactile measuring devices" describes methods to do both. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text At its meeting in October 2014, the EURAMET TC for Length, decided upon a key comparison on the calibration of diameter gauges, named EURAMET.L-K4.2015. Twenty National Metrology Institutes and one Designated Institute from Europe, Asia and South America participated in this comparison, which was carried out in two parallel groups. Twelve laboratories from EURAMET participated in group 1, while ten laboratories from EURAMET and two laboratories from GULFMET and SIM participated in group 2. To provide the link three laboratories, CEM, INRIM and METAS, participated in both groups and in the key comparison CCL-K4.2015. Two sets of gauges consisting of two rings, two plugs and a sphere were circulated in parallel in the two groups, the circulation started in November 2016 and completed in February 2018. The reference value (KCRV) was calculated on a gauge-per-gauge basis as the weighted mean of the submitted results of the diameter, roundness and straightness measurements. With group 1, inconsistent results (En> 1) gave a number of 5 out of 60 independent results for diameter and 7 out of 77 for roundness, while with group 2 a number of 6 out of 59 for diameter. These numbers are reflected in the comparison with reference values, while it is worth noting that with the two plugs of 100 mm diameter a decrement of 2 inconsistent results is achieved by introducing an uncertainty contribution related to the apparent change of length of these gauges. Furthermore, the KCRV was calculated by linking the two groups for the diameter of all the twin gauges and for the roundness of the twin spheres. When compared to those calculated independently for each group, minor changes of the KCRVs and associated uncertainties are observed from linking the groups. Consistency checks are satisfied for most of the gauges with the exception of the plugs 100 mm, which suffer from an apparent change in length during the circulation. With the linking, inconsistent results gave a number of 12 out of 119 independent results for the diameter and 1 out of 21 for roundness of the sphere. The comparison results help to support the calibration and measurement capabilities (CMCs) of the laboratories, while recommendations and actions were agreed with those having inconsistent 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text This intercomparison is carried out for step height standards with nominal step sizes 8 nm, 18 nm, 88 nm and 10 µm using non-contact measurement methods, with four participating NMIs. Measurement observation from the pilot laboratory exhibit significant stability of step height standards. For each step height standard, the supplementary comparison reference value (SCRV) is determined using weighted mean, followed by calculation of En values for outlier identification. Further the outliers were excluded based upon the Birge Ratio consistency test. Measurement results from all the participating NIMs have been compiled in this report. 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).

It has been brought to the attention of IOP Publishing that this Technical Supplement has been published in error and is an unintended duplication of a previously published manuscript (https://iopscience.iop.org/article/10.1088/0026-1394/54/1A/04004). As such, this Technical Supplement is being retracted by IOP Publishing Limited with the agreement of BIPM and all the authors.

Supplementary comparison of distance measurements using pocket-type laser instruments (EDMs), following the previous comparison EURAMET.L-S20. Originally proposed by the CEM (ES) as a bilateral comparison with BEV (AT), after the open call made at the 2014 EURAMET TC-L meeting, VSL (NL) joined the comparison too. Registered as supplementary comparison EURAMET.L-S25 with CEM acting as coordinator and pilot laboratory. Transfer devices were two Leica DISTO EDMs, being the measurands the distances from the rear part of the EDMs to a target plate situated at 0.3 m and every 5 m until covering a range of 50 m. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The results of the inter-RMO key comparison EURAMET.L-K5.2016 on the calibration of a step gauge are reported. Twenty-two National Metrology Institutes from four different metrological regions all over the world participated in this comparison which lasted three years, from December 2015 to December 2018. Two artefacts were circulated so that the varying ranges of participants equipment could be accommodated. A 1020 mm ceramic monolithic step gauge remained stable throughout the comparison. A 610 mm steel step gauge changed length, possibly due to an impact while travelling between participants. The comparison of this artefact was divided into two groups, those before the damage and those after, with the reference value for each group derived from a linking participant who had demonstrated equivalence in the 1020 mm artefact circulation. For the 1020 mm comparison the inverse-variance weighted mean was taken as reference value. Of the twenty two participants, eleven successfully demonstrated the validity of the claimed measurement capability. Of the remaining 11, 3 submitted revised uncertainties after the initial circulation of results which were shown to be valid when compared to the reference value. A set of recommendations and actions were agreed with the remaining participants. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The key comparison EURAMET.L-K8.2013 on roughness was carried out in the framework of a EURAMET project starting in 2013 and ending in 2015. It involved the participation of 17 National Metrology Institutes from Europe, Asia, South America and Africa representing four regional metrology organisations. Five surface texture standards of different type were circulated and on each of the standards several roughness parameters according to the standard ISO 4287 had to be determined. 32 out of 395 individual results were not consistent with the reference value. After some corrective actions the number of inconsistent results could be reduced to 20, which correspond to about 5% of the total and can statistically be expected. In addition to the material standards, two softgauges were circulated, which allow to test the software of the instruments used in the comparison. The comparison results help to support the calibraton and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Die Bestimmung der Grundwerte eines Widerstandsthermometers ist ein typisches Beispiel, bei dem die eigentlichen Messgrößen durch eine Ausgleichsrechnung aus einer veränderlichen Anzahl von Messdaten gewonnen werden. Die notwendige Angabe der Messunsicherheit (nach GUM) solcher Größen bereitet den Anwendern erfahrungsgemäß große Schwierigkeiten. In dieser Arbeit werden für Praktiker GUM-konsistente Formeln für die Messunsicherheit der Koeffizienten einer Ausgleichsparabel abgeleitet.

Distribution temperature is a concept that assigns a temperature to radiation from an incandescent lamp, which has a relative spectral power distribution reasonably close to that of a blackbody radiator. Different least square estimation methods for determination of distribution temperature are compared. Their applicability is discussed with regard to uncertainties of the spectral irradiance data of incandescent lamps. Simulation results are analysed to support theoretical conclusions. Experimental results indicate that the estimation method currently recommended by CIE will lead to feasible results only if the relative uncertainties of spectral irradiance data over the chosen wavelength region can be presumed constant. Otherwise, the use of this estimation method weighted with the relative uncertainties is suggested.

Die Bestimmung des linearen thermischen Ausdehnungskoeffizienten eines Prüflings ist ein typisches Beispiel, wie die eigentliche Messgröße durch eine Ausgleichsrechnung aus einer veränderlichen Anzahl von Messdaten gewonnen wird. Die notwendige Angabe der Messunsicherheit (nach GUM) solcher Größen bereitet den Anwendern erfahrungsgemäß große Schwierigkeiten. In dieser Arbeit werden für Praktiker GUM-konsistente Formeln für die Messunsicherheit der Koeffizienten von Ausgleichsgeraden abgeleitet.

Lasers from ten national metrology institutes (NMIs) plus the institutes responsible for Chinese Taipei and Hong Kong, China, were compared as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comit? Consultative des Longueurs (CCL) in 2007. The absolute frequency of the f component of the R(127) 11-5 transition of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in the present report. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Lasers from three national metrological institutes (NMIs) were compared in 2013 as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comite Consultative des Longuers (CCL) in 2007. The absolute frequency of R(127) 11-5 transitions of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in this report. The comparison reports, as communicated by each participant, are included as appendices.

An international comparison of He-Ne/I2 lasers at λ = 633 nm between the CMI (Czech Republic), the OMH (Hungary) and the BEV (Austria) was performed at the CMI-LPM, Prague, in July 1997 as DUNAMET project D3. The frequencies of three national standards of length (lasers) were found to be in the range 7 kHz (1.5 parts in 1011) and reproducibility of frequency differences between individual lasers during one week was better than 5 kHz (1 part in 1011). The relative frequency stability, expressed as an Allan standard deviation, reached a minimum of 3 parts in 1013 for an integration time of 10000 s.

During the EURAMET TC-F meeting of 2014 and following the finalization of CCM.FF-K4.2.2011 comparison, it was agreed to start a Regional Key Comparison (KC) on volume measurements using two 100 μL micropipettes (piston pipettes) allowing the participating laboratories to assess the agreement of their results and uncertainties. Two 100 μL micropipettes were tested by 15 participants. One participant was not a member or associate member of the BIPM and was be removed from this report. The comparison started in July 2015 and ended in March 2016. The Volume and Flow Laboratory of the Portuguese Institute for Quality (IPQ) was the pilot laboratory and performed the initial and final measurements of the micropipettes. The micropipettes showed a stable volume during the whole comparison, which was confirmed by the results from the pilot laboratory. The original results of all participant NMIs were corrected to the standard atmospheric pressure in order to compare results under the same calibration conditions, and the contribution of the 'process-related handling contribution' was added to the uncertainty budget of each participant. In general the declared CMCs are in accordance with the KCDB. For the micropipette 354828Z, two laboratories had inconsistent results. For micropipette 354853Z, three laboratories had inconsistent results. 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 (CIPM MRA).

Lasers from four national metrological institutes (NMIs) were compared in 2014 as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comité Consultative des Longuers (CCL) in 2007. The absolute frequency of R(127) 11-5 transitions of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in the present report. The comparison reports, as communicated by each participant, are included as appendices. This document constitutes the sixth final report for the ongoing key comparison CCL-K11. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In October 2012, the EURAMET Technical Committee for Length, TC-L, decided upon a supplementary comparison on gauge block measurements by mechanical comparison, numbered EURAMET.L-S22, with the Danish Technological Institute (DTI) as the pilot laboratory, assisted by NPL (Andrew Lewis), which would provide a link to CCL-K1. The comparison was registered in February 2013, artefact circulation starts in June 2013 and ended in September 2014. Eight gauge blocks were calibrated using a five point measurement. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Lasers from nine national metrology institutes (NMIs) were compared as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comite Consultative des Longeurs (CCL) in 2007. The absolute frequency of the f component of the R(127) 11–5 transition of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in the present report. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

The key comparison EURAMET.L-K1.2011 on gauge blocks was carried out in the framework of a EURAMET project starting in 2012 and ending in 2015. It involved the participation of 24 National Metrology Institutes from Europe and Egypt, respectively. 38 gauge blocks of steel and ceramic with nominal central lengths between 0.5 mm and 500 mm were circulated. The comparison was conducted in two loops with two sets of artifacts. A statistical technique for linking the reference values was applied. As a consequence the reference value of one loop is influenced by the measurements of the other loop although they did not even see the artifacts of the others. This influence comes solely from three "linking laboratories" which measure both sets of artifacts. In total there were 44 results were not fully consistent with the reference values. This represents 10% of the full set of 420 results which is a considerable high number. At least 12 of them are clearly outliers where the participants have been informed by the pilot as soon as possible. The comparison results help to support the calibration and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The results of the comparison of parallel thread gauges between ten European countries are presented. Three thread plugs and three thread rings were calibrated in one loop. Croatian National Laboratory for Length (HMI/FSB-LPMD) acted as the coordinator and pilot laboratory of the comparison. Thread angle, thread pitch, simple pitch diameter and pitch diameter were measured. Pitch diameters were calibrated within 1a, 2a, 1b and 2b calibration categories in accordance with the EURAMET cg-10 calibration guide. A good agreement between the measurement results and differences due to different calibration categories are analysed in this paper. This comparison was a first EURAMET comparison of parallel thread gauges based on the EURAMET ctg-10 calibration guide, and has made a step towards the harmonization of future comparisons with the registration of CMC values for thread gauges.

The results of the supplementary comparison EURAMET.L-S20 of laser distance measuring instruments (EDMs) are reported. It was the first comparison of EDMs. Four EDMs were circulated among 13 European NMIs. Each EDM was calibrated at a distance of 0.3 m and at regularly spaced intervals every 5 m for a range up to 50 m. The measurements were conducted between 2011 and 2012. The test of the stability of the EDMs showed significant changes in the mean results over timescales of months or even days. The uncertainty of the results mainly comes from the uncertainty due to the reproducibility, and it is difficult to distinguish the part relevant to the laboratories' calibration and measurement capabilities. For the analysis both the deviations from the reference value and the En numbers were calculated. For the evaluation of the reference value, the weighted mean approach has been chosen, although the consistency check failed in many cases. A more complicated procedure for the evaluation of the reference value was proposed, which slightly changes the uncertainty of the reference value. Most results agreed within the claimed uncertainties. Some 4.7% of the results showed some larger deviations. Some participants may have a high percentage of values that are not compliant with their CMC claims due to the influence of the artifact and the estimation of its uncertainty. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The results of the inter-RMO key comparison EUROMET.L-K5.2004 on the calibration of a step gauge are reported. Eighteen National Metrology Institutes and one Designated Institute from four different metrological regions all over the world participated in this comparison which lasted three years, from December 2004 to December 2007. A lack of stability was observed through the shifting of some of the inserted gauges. In order to save the comparison and get valuable and useful conclusions, it was agreed to exclude four gauges from calculation and assume that only seven gauges were reasonably stable so as to get the corresponding reference values. It was also agreed to divide the participants into two groups, analyze separately their results and, taking the pilot as the linking laboratory, refer the results to common reference values. The inverse-variance weighted mean was taken as reference value. Due to the significant instability of the step it was also considered an artefact uncertainty. The reported uncertainties ranged from 0.045 ?m to 1.2 ?m (k = 1). The uncertainty of the artefact ranged from 0.018 ?m (for the 20 mm face) to 0.176 ?m (for the 400 mm face). The compatibility of all participants for measuring step gauges was demonstrated with the only exception of a participant showing very high systematic (both positive and negative) errors. Five participants communicated higher uncertainties than the corresponding approved CMCs. A set of Recommendations and Actions were agreed therefore. 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).