CCT-K7水三相点容器国际关键比对

在国际互认框架内,国家计量标准的国际等效性是通过国际计量委员会（CIPM）的咨询委员会组织的一系列国际关键比对来确定的。温度咨询委员会（CCT）委托国际计量局（BIPM）作为主导实验室组织了由20个国家实验室参加的CCT-K7水三相点容器国际关键比对。比对结果表明：这些国家基准水三相点值在0．171mK范围内一致。此外,为了减小国家实验室复现水三相点的系统差,需要进一步研究同位素组成对水三相点温度的影响以及同位素修正。     

Recent developments in BIPM voltage standard comparisons

The Bureau International des Poids et Measures (BIPM) carries out a number of comparisons of dc voltage standards with National Metrology Institutes (NMIs). These take the form of on-site comparisons of Josephson standards or bilateral comparisons using traveling standards based on Zener diodes. This paper describes some of the new procedures used in both types of comparison and presents some results of five recent BIPM key comparisons     

A Trial Intercomparison of Humidity Generators at Extremes of Range Using Relative Humidity Transmitters

In order to effectively implement the Mutual Recognition Arrangement (MRA) of the International Committee for Weights and Measures (CIPM), national metrology institutes (NMIs) are required to support their claims of calibration and measurement capability (CMC) with a quality system compliant with ISO/IEC 17025, and with suitable evidence of participation in key or supplementary comparisons. The CMC review process, both at regional and inter-regional levels, uses criteria that combine the provisions mentioned above, together with additional evidence demonstrating scientific and technical competence of the institutes. For dew-point temperatures, there are key comparisons in progress under the Consultative Committee for Thermometry (CCT) and under the European regional metrology organisation (EUROMET), together with information available on past regional supplementary comparisons. However, for relative humidity there are, to date, no such comparisons available to support CMC entries. This paper presents and discusses the results of a preliminary investigation of the use of relative humidity and temperature transmitters in order to determine their suitability for the intercomparison of standard humidity generators in support of CMC claims for the calibration of relative humidity instruments. The results of a recent bilateral comparison between 2 NMIs at the extremes of the range up to 98%rh at 70 °C, and down to 1%rh at −40 °C are reported. Specific precautions and recommendations on the use of the devices as transfer standards are presented.     

Key comparisons of the VNIIM and BIPM voltage standards

The results of key comparisons of the national primary standard of Russia for the unit of electrical voltage, the volt, at the Mendeleev Institute of Metrology (VNIIM) with the Josephson effect voltage standard at the BIPM are reported. For these measurements, VNIIM provided a voltage measure based on the Josephson effect with a nominal output voltage of 10 V. Measurements were made with apparatus from the BIPM voltage standard. The VNIIM voltage measure is planned for use as a transfer standard for comparison with national standards for the volt. The comparisons indicate a high degree of equivalence of the compared VNIIM and BIPM primary standards with a relative combined standard uncertainty of 2·10–10 at 10 V.     

中国参加温度关键比对结果分析

本文介绍了国际计量委员会(CIPM)组织国际关键比对的背景和已经开展的温度比对项目。对中国计量科学研究院参加的温度比对项目进行了系统介绍和结果分析。     

International comparison of the spectral responsivities of silicon photodetectors

The results are considered of a comparison of the national scales of spectral responsivity of 18 national metrological laboratories including the All-Union Scientific-Research Institute of Optophysical Measurements (VNIIOFI) between themselves and with the scale of the International Bureau of Weights and Measures (BIPM) in the spectral wavelength range 250–1000 nm using two different types of silicon photodetector. The comparisons indicated satisfactory agreement between the results of measurements of spectral responsivity by the participating laboratories. The difference between the spectral responsivity scale of VNIIOFI and that of the BIPM did not exceed ±0.5% for the visible wavelength range and the near infrared. The maximum difference of the scales in the near ultraviolet wavelength range was 3.7%. Translated from Izmeritel'naya Tekhnika, No. 1, pp. 59–63, January, 1999.     

基于校准与测量能力分布探析我国流量计量研究方向

基于国际计量委员会流体流量工作组流量领域关键比对的分类体系, 统计了流量领域校准与测量能力（CMC）总数排名前十经济体的校准与测量能力,对各经济体的流量计量基准、标准装置的测量原理、测量范围、标准相对不确定度等进行对比分析,得到各经济体流量领域的校准与测量能力分布和发展现状。针对我国流量领域的CMC现状,提出未来研究方向,为我国流量领域的校准与测量能力复评审提供支撑。     

4πγ井型NaI晶体测量装置开展医用核素99Tcm活度测量的国际比对

⁹⁹Tc^m为目前在核医学领域应用最为广泛的短寿命放射性核素,其活度值的准确性至关重要,为此国际计量局组织了⁹⁹Tc^m核素活度国际关键比对。2012 年3月,中国计量科学研究院电离辐射所采用4πγ井型NaI晶体国际参考系统传递仪器（SIRTI）完成了医用核素99Tcm的比对实验。稳定性测试结果表明SIRTI仪器工作状态满足比对要求,比对核素⁹⁹Tc^m的活度当量测量结果在12.580 kBq左右。     

低能X射线空气比释动能国际关键比对

为促进我国在低能X射线空气比释动能计量领域内的量值统一并达到国际等效,中国计量科学研究院(NIM)于2018年采用平板自由空气基准电离室复现低能X射线空气比释动能,并通过传递电离室Radcal-RC6M在国际计量局(BIPM)低能X射线辐射场中开展了间接比对,其比对结果在合成标准不确定度为0.37%范围内与国际计量局等效一致,该比对结果已纳入国际计量局的关键比对数据库(KCDB)。     

Comparison of the NIST and BIPM Air-Kerma Standards for Measurements in the Low-Energy X-Ray Range

A direct comparison was made between the air-kerma standards used for the measurement of low-energy x rays at the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM). The comparison was carried out at the BIPM using the BIPM reference beam qualities in the range from 10 kV to 100 kV. The results show the standards to be in agreement to around 0.5 % at reference beam qualities up to 50 kV and at 100 kV. The result at the 80 kV beam quality is less favorable, with agreement at the 1 % level.     

Comparison of the NIST and BIPM Medium-Energy X-Ray Air-Kerma Measurements

The air-kerma standards used for the measurement of medium-energy x rays were compared at the National Institute of Standards and Technology (NIST) and at the Bureau International des Poids et Mesures (BIPM). The comparison involved a series of measurements at the BIPM and the NIST using the air-kerma standards and two NIST reference-class transfer ionization standards. Reference beam qualities in the range from 60 kV to 300 kV were used. The results show the standards to be in agreement within the combined standard uncertainty of the comparison of 0.35 %.     

Comparison of the NIST and BIPM Standards for Air Kerma in Medium-Energy X-Rays

A comparison has been made of the air-kerma standards for medium-energy x-rays of the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM). The comparison involved a series of measurements at the BIPM and the NIST using the air-kerma standards and three NIST reference-class transfer ionization chamber standards. Reference beam qualities in the range from 100 kV to 250 kV were used. The results show the standards to be in reasonable agreement within the combined standard uncertainty of the comparison of 0.37 %, although a significant trend with radiation quality is observed and the possible sources discussed.     

International comparison of thermal noise-temperature measurementsat 2, 4, and 12 GHz

We discuss an international comparison of thermal noise-power measurements (GTRF-92-2), which has recently been completed under the auspices of the Consultative Committee for Electricity and Magnetism (CCEM). The noise temperatures of two solid-state sources with GPC-7 connectors were measured at 2, 4, and 12 GHz at the national laboratories in France, Germany, the United Kingdom, and the United States. Good agreement was found among the results from the different laboratories, with all results agreeing within the expanded uncertainties, which ranged from approximately 0.5% to 2.9%. The comparison was performed in accordance with the guidelines recently adopted by the Bureau International des Poids et Mesures (BIPM)     

Special Report on Electrical Standards: New Internationally Adopted Reference Standards of Voltage and Resistance

This report provides the background for and summarizes the main results of the 18th meeting of the Consultative Committee on Electricity (CCE) of the International Committee of Weights and Measures (CIPM) held in September 1988. Also included are the most important implications of these results. The principal recommendations originating from the meeting, which were subsequently adopted by the CIPM, establish new international reference standards of voltage and resistance based on the Josephson effect and the quantum Hall effect, respectively. The new standards, which are to come into effect starting January 1, 1990, will result in improved uniformity of electrical measurements worldwide and their consistency with the International System of Units or SI. To implement the CIPM recommendations in the U.S. requires that, on January 1, 1990, the value of the U.S. representation of the volt be increased by about 9.26 parts per million (ppm) and the value of the U.S. representation of the ohm be increased by about 1.69 ppm. The resulting increases in the U.S. representations of the ampere and watt will be about 7.57 ppm and 16.84 ppm, respectively. The CCE also recommended a particular method, affirmed by the CIPM, of reporting calibration results obtained with the new reference standards that is to be used by all national standards laboratories.     

Summary of International Comparisons of As-Maintained Units of Voltage and Values of 2e/h

Using temperature-regulated transportable standard-cell enclosures, the National Bureau of Standards (NBS), under the auspices of the Bureau International des Poids et Mesures (BIPM), during the period June 1971 through June 1972 has carried out a series of direct comparisons of the units of voltage as-maintained by NBS and BIPM, Sèvres, France; the National Physical Laboratory, United Kingdom; the National Research Council, Canada; the National Standards Laboratory, Australia; and the Physikalisch-Technische Bundesanstalt, Germany. The main purpose of these comparisons was to provide a sound basis for intercomparing values of 2e/h obtained at the various national laboratories via the ac Josephson effect in superconductors. It was found that when converted to a common unit of voltage, most measured values of 2e/h agreed with each other to within the 1 to 2 parts in 107 estimated uncertainty (1 standard deviation) of the volt comparisons. This satisfying result would seem to indicate that serious consideration should be given to adopting a single international value of 2e/h for use in maintaining units of voltage.     

Results of International Comparisons Using Methane-Stabilized He-Ne Lasers at 3.39 ?m and Iodine-Stabilized He-Ne Lasers at 633 nm

The results of international comparisons of methane-stabilized He-Ne lasers at ? = 3.39 ?m and iodine-stabilized He-Ne lasers at 633 nm, made by beat frequency techniques, between Bureau International des Poids et Mesures (BIPM) and eleven national laboratories are presented. Generally, the measured frequency differences were inside ±4 × 10-11; but greater frequency differences were observed with some iodine cells (probably as a result of contamination) or when the output power of one laser was two or three times greater than the power of the other laser.     

绝对重力仪国际比对新动态

全球绝对重力仪国际比对活动从1981年起每隔4年在法国国际计量局举办。近两年来,该比对活动发生了一些变化,同时,区域性绝对重力仪国际比对活动日益兴起。中国计量科学研究院代表我国参与了这方面的工作,并介绍了中国计量科学研究自主研制的NIM-II型绝对重力仪参加2009年第8届全球绝对重力仪国际比对的情况和结果     

Special Report on Standards for Radioactivity: Report on the 1989 Meeting of the Radionuclide Measurements Section of the Consultative Committee on Standards for the Measurement of Ionizing Radiations

This report describes the activities discussed at the 10th meeting of Section II of the Consultative Committee on Standards for the Measurement of Ionizing Radiations (Comité Consultatif pour les Etalons de Mesure des Rayonnements Ionisants, CCEMRI) held in May 1989 at Sèvres (France). Topics included present and future international comparisons of activity measurements, the status and possible extension of the International reference system for activity measurements of gamma-ray emitting nuclides, reports from other working groups, accomplishments at the International Bureau of Weights and Measures (Bureau International des Poids et Mesures, BIPM), and progress at member laboratories.