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Final report on CCM.M-K4: Key comparison of 1 kg stainless steel mass standards
Becerra, Luis Omar,orys, Michael,Chung, Jin Wan,Davidson, Stuart,Fuchs, Peter,Jacques, Claude,Jian, Wang,Kubarych, Zeina J,Kumar, Anil,Malengo, Andrea,Fen, Kitty,Medina, Nieves,Meury, Paul-André BUREAU INTERNATIONAL DES POIDS ET MESURES 2014 METROLOGIA -BERLIN- Vol.51 No.-
<P>This report describes a key comparison of 1 kg stainless steel mass standards, CCM.M-K4, undertaken by the Consultative Committee for Mass and Related Quantities (CCM) Working Group on the Dissemination of the kilogram (WGD-kg). The CCM.M-K4 comparison was launched during the 12th meeting of the CCM (2010). The aim of the present comparison is to verify the consistency of 1 kg stainless steel mass standards among members of the CCM.</P><P>The previous CCM 1 kg stainless steel mass standards comparison was carried out in 1995–1997 as the CCM.M-K1 comparison. The Bureau International des Poids et Mesures (BIPM) was the pilot laboratory for this key comparison. There were sixteen participants in the CCM.M-K4 comparison, all are CCM members. The comparison was structured into four petals with two stainless steel travelling mass standards per petal. The measurements and the reported results were completed in between one month and five months depending on the participants. One laboratory's results were found to be inconsistent with the other laboratories' results and one other laboratory gave a significant deviation from the key comparison reference value (KCRV). Both laboratories were contacted before preparation of the draft A report, without disclosing the details of the deviations, to allow them to check and revise their values. The fourteen other participants were in agreement with each other and degrees of equivalence have been established.</P><P>Finally, the mass values of the eight stainless steel travelling standards were determined in air by the NMIs with claimed standard uncertainties ranging from 0.007 mg to 0.021 mg. Degrees of equivalence have been established by using the generalized linear least-squares estimation (GLS) method. The result demonstrates the high quality of this comparison and that some participants are able to provide, for their mass calibration services, standard uncertainties of around ten micrograms. The good uniformity of worldwide mass dissemination since the last periodic mass verification carried out in 1992 is demonstrated by the agreement among the NMIs' results. In addition, the observed weighted mean of the NMI deviations against the BIPM is −0.0098 mg (σ = 0.0036 mg). Despite the good result obtained in this particular comparison we should, in order to have a more accurate calibration system, improve the knowledge of the ageing effects of the mass references and increase the BIPM calibration frequency of the national prototypes.</P><P>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/.</P><P>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).</P>
Shim, Jeong Hyun,Lee, Seong-Joo,Hwang, Seong-min,Yu, Kwon Kyu,Kim, Kiwoong BUREAU INTERNATIONAL DES POIDS ET MESURES 2015 METROLOGIA -BERLIN- Vol.52 No.4
<P>We demonstrate a proton spin echo magnetometer, in which the interrogation time is not limited by <img SRC='http://ej.iop.org/images/0026-1394/52/4/496/met513248ieqn001.gif' ALIGN='MIDDLE' ALT='$T_{2}^{*}$ '/> and can be prolonged to <I>T</I><SUB>2</SUB>. Therefore, even under a severe field gradient, the precision of the measurement does not degrade. We devised a phase linearization method that enables accurate estimation of the precession frequency from a spin-echo train. With proton spins in deoxygenated tetramethylsilane and a superconducting quantum interference device-detected NMR system at KRISS, an average field of around 5 μT was measured with an uncertainty of 0.42 nT in the presence of a field gradient of 12.8 μT m<SUP>−1</SUP>. This implies that our system tolerated a 25% variation in magnetic field over the sample area. The proton spin-echo magnetometer will be useful in measuring magnetic fields without compensating for residual field gradients.</P>
Joung, Wukchul,Pearce, Jonathan V,Park, Jihye BUREAU INTERNATIONAL DES POIDS ET MESURES 2018 METROLOGIA -BERLIN- Vol.55 No.3
<P>In this work, the consistency of the heat pulse-based melting technique, which was used to determine the liquidus temperature of tin, was examined by comparing the liquidus temperatures of tin at 101 325 Pa and at the vapour pressure of tin (i.e. the triple-point temperature), both of which were realized by heat pulse-based melting. Periodic square wave-type temperature steps with an amplitude of 0.7 °C were generated in the isothermal region of the pressure-controlled loop heat pipe, and the tin sample, having a segregated impurity distribution established by the prior outward slow freezing, was melted by application of the temperature step-based heat pulses. The triple-point temperature was found to be lower than the liquidus temperature of tin at 101 325 Pa by 3.23 mK with an expanded measurement uncertainty of 0.24 mK (i.e. a coverage factor of <I>k</I> = 2), while the ideal temperature difference calculated from the ITS-90 given pressure coefficient (i.e. 3.3 × 10<SUP>−8</SUP> K Pa<SUP>−1</SUP>) is about 3.34 mK. The difference between the measured temperature difference and ideal temperature difference was attributed to the incomplete removal of the gases in the tin triple-point cell. Overall, these results further corroborated the notion that the heat pulse-based melting technique was shown to yield results consistent with the prescription of the ITS-90, and to be a reliable method in terms of the realization of the fixed-point temperatures.</P>
Precision measurement of a potential-profile tunable single-electron pump
Bae, Myung-Ho,Ahn, Ye-Hwan,Seo, Minky,Chung, Yunchul,Fletcher, J D,Giblin, S P,Kataoka, M,Kim, Nam BUREAU INTERNATIONAL DES POIDS ET MESURES 2015 METROLOGIA -BERLIN- Vol.52 No.2
<P>We performed a precision measurement of the current from a single-parameter electron pump, where the potential-profile for a quantum dot was manipulated by multiple top-metal gates. In an optimally tuned condition, driven with a sinusoidal-waveform microwave at <I>f</I> = 0.95 GHz, <I>B</I> = 11 T, and <I>T</I> = 0.3 K, the relative deviation of the pump current from <I>ef</I>, <I>δI</I><SUB><I>p</I></SUB>/<I>ef</I>?≡?(<I>I</I><SUB><I>p</I></SUB>?−?<I>ef</I>)/<I>ef</I> was measured to be (−0.92 ??? 1.37) ppm. Our experiment reproduces the current quantisation accuracy of a previous measurement of a single-parameter pump, but in a device fabricated using very different geometry, thereby indicating that accurate single-parameter pumping is insensitive to device details.</P>
Bilateral comparison of DC magnetic flux density between NML-SIRIM and KRISS (P1-APMP.EM-S13)
Park, Po Gyu,Kim, Wan-Seop,Gyun Kim, Young,Mohd Amran, Shakirah BUREAU INTERNATIONAL DES POIDS ET MESURES 2014 METROLOGIA -BERLIN- Vol.51 No.-
<P>A bilateral comparison of magnetic flux density has been performed between Korea Research Institute of Standards and Science (KRISS) and National Metrology Laboratory, SIRIM (NML-SIRIM), and registered as APMP.EM-S13 in the BIPM key comparison database. This comparison was piloted by KRISS and the results of the NML-SIRIM were linked to those of the CCEM.M-K1 key comparison through KRISS. The mean value of the coil constant and the uncertainty of the mean reported by both laboratories were used in the calculation of the degree of equivalence (DOE).</P><P>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/.</P><P>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).</P>
Benková,, Miroslava,Makovnik, Stefan,Mickan, Bodo,Arias, Roberto,Chahine, Khaled,Funaki, Tatsuya,Li, Chunhui,Choi, Hae Man,Seredyuk, Denys,Su, Chun-Min,Windenberg, Christophe,Wright, John BUREAU INTERNATIONAL DES POIDS ET MESURES 2014 METROLOGIA -BERLIN- Vol.51 No.-
<P>The comparison CCM.FF-K6.2011 was organized for the purpose of determination of the degree of equivalence of the national standards for low-pressure gas flow measurement over the range (2 to 100) m<SUP>3</SUP>/h. A rotary gas meter was used as a transfer standard. The measurements were provided at prescribed reference conditions. Eleven laboratories from four RMOs participated in this key comparison—EURAMET: PTB, Germany; SMU, Slovakia; LNE-LADG, France; SIM: NIST, USA; CENAM, Mexico; APMP: NMIJ AIST Japan; KRISS, Korea; NMI, Australia; NIM, China; CMS, Chinese Taipei; COOMET: GP GP Ivano-Frankivs'kstandart-metrologia, Ukraine and all participants reported independent traceability chains to the SI. All results were used in the determination of the key comparison reference value (KCRV) and the uncertainty of the KCRV. The reference value was determined at each flow separately following procedure A presented by M G Cox. The degree of equivalence with the KCRV was also calculated for each flow and laboratory. All reported results were consistent with the KCRV. This KCRV can now be used in the further regional comparisons.</P><P>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/.</P><P>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).</P>
Brown, Richard J C,Brewer, Paul J,Ent, Hugo,Fisicaro, Paola,Horvat, Milena,Kim, Ki-Hyun,Qu?tel, Christophe R BUREAU INTERNATIONAL DES POIDS ET MESURES 2015 METROLOGIA -BERLIN- Vol.52 No.5
<P>This paper considers how decisions on internationally recommended datasets are made and implemented and, further, how the ownership of these decisions comes about. Examples are given of conventionally agreed data and values where the responsibility is clear and comes about through official designation or by common usage and practice over long time periods. The example of the dataset describing the mass concentration of mercury in air at saturation is discussed in detail. This is a case where there are now several competing datasets that are in disagreement with each other, some with historical authority and some more recent but, arguably, with more robust metrological traceability to the SI. Further, it is elaborated that there is no body charged with the responsibility to make a decision on an international recommendation for such a dataset. This has led to the situation where several competing datasets are in use simultaneously. Close parallels are drawn with the current debate over changes to the ozone absorption cross section, which has equal importance to the measurement of ozone amount fraction in air and to subsequent compliance with air quality legislation. It is noted that in the case of the ozone cross section there is already a committee appointed to deliberate over any change. We make the proposal that a similar committee, under the auspices of IUPAC or the CIPM's CCQM (if it adopted a reference data function) could be formed to perform a similar role for the mass concentration of mercury in air at saturation.</P>