Pub Date : 2023-11-08DOI: 10.1088/1681-7575/ad0abe
Joele Viallon, Christopher W Meyer, Philippe Moussay, J W Schmidt, Stephen E Maxwell, Fredrik Arrhen, Robert Wielgosz
Abstract The design, performance characteristics and validation of a next generation reference facility for CO 2 in air standards based on manometry is presented. Novel attributes of the facility include automated operation, avoidance of significant pressure corrections for measurements on extracted CO 2 , fully characterized trapping efficiencies, and reduced measurement uncertainty. 
Improvements in system performance have been achieved using specific materials, notably Silconert®-treated stainless-steel , providing increased mechanical stability whilst minimizing carbon dioxide adsorption on surfaces, and avoiding use of elastomer O-rings, which would lead to losses of CO 2 . Full automation of the cryogenic extraction process of CO 2 from air has been achieved, avoiding any manual intervention within the temperature stabilized section of the facility, and allowed full characterization and correction for trapping efficiencies and trace water measurement.
The facility has been validated across the CO 2 in air amount fraction range of (380 to 800) µmol mol −1 using standards with values traceable to the reference value of the CCQM−K120 (2018) comparison. It was demonstrated to operate with a standard measurement uncertainty of 0.09 µmol mol −1 at 400 µmol mol −1 . The automation allows five measurement results per day to be produced with a typical standard deviation of the mean at or below 0.02 µmol mol −1 .
The facility will be used as a stable reference in the future ongoing BIPM.QM−K2 comparison, to compare consistency of amount fraction values in different CO 2 in air standards. The CO 2 amount fraction in two ensembles of nine BIPM standards covering the same range will also be measured with the facility to provide their SI-traceable values, and further monitored on a longer time scale. Each ensemble will constitute a CO 2 in air scale for comparison with other available scales such as WMO.CO2.X2019 through the BIPM.QM−K5 comparison.
{"title":"A high accuracy reference facility for ongoing comparisons of CO<sub>2</sub> in air standards","authors":"Joele Viallon, Christopher W Meyer, Philippe Moussay, J W Schmidt, Stephen E Maxwell, Fredrik Arrhen, Robert Wielgosz","doi":"10.1088/1681-7575/ad0abe","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0abe","url":null,"abstract":"Abstract The design, performance characteristics and validation of a next generation reference facility for CO 2 in air standards based on manometry is presented. Novel attributes of the facility include automated operation, avoidance of significant pressure corrections for measurements on extracted CO 2 , fully characterized trapping efficiencies, and reduced measurement uncertainty. &#xD;Improvements in system performance have been achieved using specific materials, notably Silconert®-treated stainless-steel , providing increased mechanical stability whilst minimizing carbon dioxide adsorption on surfaces, and avoiding use of elastomer O-rings, which would lead to losses of CO 2 . Full automation of the cryogenic extraction process of CO 2 from air has been achieved, avoiding any manual intervention within the temperature stabilized section of the facility, and allowed full characterization and correction for trapping efficiencies and trace water measurement.&#xD;The facility has been validated across the CO 2 in air amount fraction range of (380 to 800) µmol mol −1 using standards with values traceable to the reference value of the CCQM−K120 (2018) comparison. It was demonstrated to operate with a standard measurement uncertainty of 0.09 µmol mol −1 at 400 µmol mol −1 . The automation allows five measurement results per day to be produced with a typical standard deviation of the mean at or below 0.02 µmol mol −1 .&#xD;The facility will be used as a stable reference in the future ongoing BIPM.QM−K2 comparison, to compare consistency of amount fraction values in different CO 2 in air standards. The CO 2 amount fraction in two ensembles of nine BIPM standards covering the same range will also be measured with the facility to provide their SI-traceable values, and further monitored on a longer time scale. Each ensemble will constitute a CO 2 in air scale for comparison with other available scales such as WMO.CO2.X2019 through the BIPM.QM−K5 comparison.&#xD;","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":" 23","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-07DOI: 10.1088/1681-7575/ad0a35
Allan H Harvey
Abstract Constant-volume gas thermometry data published in 1989 for the difference between the thermodynamic temperature and the International Practical Temperature Scale of 1968 are corrected in two ways. A refined estimate of the thermal expansivity of the material of the gas bulb, published in 1990, increases the thermodynamic temperature by amounts on the order of 1 mK to 3 mK. Better knowledge of the nonideality of helium gas reduces the uncertainty of the nonideality correction to near zero and decreases the thermodynamic temperature by amounts on the order of 0.1 mK to 0.5 mK. The net effect is a small increase in the thermodynamic temperature derived from the 1989 experiments. The magnitude of this increase is approximately 2 mK at 505 K, increasing to 3 mK at temperatures near 700 K, and then diminishing to near 0.5 mK at the highest temperature of the measurements (933 K). These corrections are smaller than the uncertainty of the experiments, but may be of significance for future recommendations for the relationship between the thermodynamic temperature and the consensus scale in this temperature range.
{"title":"Small Corrections to 1989 NIST Constant-Volume Gas Thermometry Data","authors":"Allan H Harvey","doi":"10.1088/1681-7575/ad0a35","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0a35","url":null,"abstract":"Abstract Constant-volume gas thermometry data published in 1989 for the difference between the thermodynamic temperature and the International Practical Temperature Scale of 1968 are corrected in two ways. A refined estimate of the thermal expansivity of the material of the gas bulb, published in 1990, increases the thermodynamic temperature by amounts on the order of 1 mK to 3 mK. Better knowledge of the nonideality of helium gas reduces the uncertainty of the nonideality correction to near zero and decreases the thermodynamic temperature by amounts on the order of 0.1 mK to 0.5 mK. The net effect is a small increase in the thermodynamic temperature derived from the 1989 experiments. The magnitude of this increase is approximately 2 mK at 505 K, increasing to 3 mK at temperatures near 700 K, and then diminishing to near 0.5 mK at the highest temperature of the measurements (933 K). These corrections are smaller than the uncertainty of the experiments, but may be of significance for future recommendations for the relationship between the thermodynamic temperature and the consensus scale in this temperature range.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"317 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135474911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-07DOI: 10.1088/1681-7575/ad0a36
Romain Maximilien Coulon, Carine Michotte, Vincent Gressier
Abstract In support of the CIPM MRA, the reference system in radionuclide metrology (SIR) is a unique experimental facility that has been able to provide continuous key comparison results for 72 radionuclides for 46 years. These measurement data are now available in a machine-readable format, which allows statistical analysis of these measurement results to be performed efficiently. Such a meta-analysis was conducted to verify whether or not the accumulated data confirmed the bold assumption made in the 1970s of the long-term robustness of the system over decades of operation. It was notably assumed that variation in the properties of the standard solution to be measured or the choice of the 226 Ra reference source would have no impact on the measurement.
For the majority of radionuclides measured by the SIR, the non-parametric significance tests of the null hypothesis carried out in this study gave no evidence, at the 95 % confidence level, that the above statement should be reconsidered. However, this meta-analysis revealed a significant impact of solution density in the case of 109 Cd, corroborating previous observations made in the case of 241 Am where the robustness of an ionization chamber with respect to the density variation of the solution does not appear to be perfect.
The extension of the SIR by a liquid scintillation system is under development. It will improve the robustness of international comparison results for those borderline cases where radionuclides emit only low-energy x-rays or gamma rays (< 100 keV).
{"title":"Evaluation of long-term robustness of the International System of Reference (SIR) used in radionuclide metrology based on the meta-analysis of its machine-readable database","authors":"Romain Maximilien Coulon, Carine Michotte, Vincent Gressier","doi":"10.1088/1681-7575/ad0a36","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0a36","url":null,"abstract":"Abstract In support of the CIPM MRA, the reference system in radionuclide metrology (SIR) is a unique experimental facility that has been able to provide continuous key comparison results for 72 radionuclides for 46 years. These measurement data are now available in a machine-readable format, which allows statistical analysis of these measurement results to be performed efficiently. Such a meta-analysis was conducted to verify whether or not the accumulated data confirmed the bold assumption made in the 1970s of the long-term robustness of the system over decades of operation. It was notably assumed that variation in the properties of the standard solution to be measured or the choice of the 226 Ra reference source would have no impact on the measurement.&#xD;For the majority of radionuclides measured by the SIR, the non-parametric significance tests of the null hypothesis carried out in this study gave no evidence, at the 95 % confidence level, that the above statement should be reconsidered. However, this meta-analysis revealed a significant impact of solution density in the case of 109 Cd, corroborating previous observations made in the case of 241 Am where the robustness of an ionization chamber with respect to the density variation of the solution does not appear to be perfect.&#xD;The extension of the SIR by a liquid scintillation system is under development. It will improve the robustness of international comparison results for those borderline cases where radionuclides emit only low-energy x-rays or gamma rays (< 100 keV).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"8 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract We present a new approach to report, in the section 4 of International Bureau of Weights and Measures Circular T, daily values of the offset between Coordinated Universal Time (UTC) and the predictions of UTC broadcast by the Global Navigation Satellite Systems (GNSS), this quantity we name bUTC GNSS . In this approach, the determination of UTC-bUTC GNSS is based on data collected by several multi-GNSS stations in selected time laboratories worldwide. Test computations over a 7-month period from July 2022 to January 2023 show that the offset between UTC and bUTC GNSS was between 30 and 50 ns for GLONASS, between 5 and 20 ns for BeiDou, and between −5 and +5 ns for GPS and Galileo. We derive the uncertainty on the reported values, which is 4.1 ns for BeiDou and GPS, 3.7 ns for Galileo and 6.6 ns for GLONASS and show that, over the test period, the reported values of UTC-bUTC GNSS and the solutions obtained from each multi-GNSS station are all consistent within the 1-sigma uncertainties.
摘要:我们提出了一种新的方法，在国际度量衡局(International Bureau of Weights and Measures Circular T)第4节中，报告协调世界时(UTC)与全球导航卫星系统(GNSS)广播的UTC预测之间的每日偏移值，我们将此量称为bUTC GNSS。在这种方法中，UTC-bUTC GNSS的确定基于全球选定时间实验室的多个多GNSS站收集的数据。从2022年7月到2023年1月的7个月的测试计算表明，GLONASS的UTC和bUTC GNSS之间的偏移量在30到50纳秒之间，北斗的偏移量在5到20纳秒之间，GPS和伽利略的偏移量在- 5到+5纳秒之间。我们推导了报告值的不确定性，北斗和GPS的不确定性为4.1 ns，伽利略的不确定性为3.7 ns, GLONASS的不确定性为6.6 ns，并表明在测试期间，UTC-bUTC GNSS的报告值与每个多GNSS站获得的解在1 σ不确定性范围内一致。
{"title":"Monitoring of the offset between UTC and its prediction broadcast by the GNSS","authors":"Pascale Defraigne, Elisa Pinat, Gerard Petit, Frédéric Meynadier","doi":"10.1088/1681-7575/ad0562","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0562","url":null,"abstract":"Abstract We present a new approach to report, in the section 4 of International Bureau of Weights and Measures Circular T, daily values of the offset between Coordinated Universal Time (UTC) and the predictions of UTC broadcast by the Global Navigation Satellite Systems (GNSS), this quantity we name bUTC GNSS . In this approach, the determination of UTC-bUTC GNSS is based on data collected by several multi-GNSS stations in selected time laboratories worldwide. Test computations over a 7-month period from July 2022 to January 2023 show that the offset between UTC and bUTC GNSS was between 30 and 50 ns for GLONASS, between 5 and 20 ns for BeiDou, and between −5 and +5 ns for GPS and Galileo. We derive the uncertainty on the reported values, which is 4.1 ns for BeiDou and GPS, 3.7 ns for Galileo and 6.6 ns for GLONASS and show that, over the test period, the reported values of UTC-bUTC GNSS and the solutions obtained from each multi-GNSS station are all consistent within the 1-sigma uncertainties.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"4 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-31DOI: 10.1088/1681-7575/ad02a0
Yiwei Wu, Siran Liu
Abstract The Bureau International des Poids et Mesures uses the ALGOS algorithm to generate the Echelle Atomique Libre. The original and new ALGOS weighting algorithms employ two different statistics to calculate the weights, resulting in different experimental phenomena. These two statistics are believed to be the keys to analyzing these experimental phenomena, because the statistical characteristics (e.g. the mathematical expectations and variances) of the statistics completely determine the statistical characteristics of the weights, and subsequently the experimental phenomena. The core work conducted in this study is to derive the analytical expressions of the mathematical expectations of these two statistics under ideal conditions and to validate them empirically. This paper provides a theoretical analysis of these expressions and discusses the relationships between them and the mathematical expectations of the Allan variances. These expressions theoretically reveal the reasons behind the experimental phenomena, especially why hydrogen masers are assigned lower weights in the original ALGOS weighting algorithm but higher weights in the new one. According to the derivation process, these analytical expressions are universally applicable and can also be applied to time-keeping laboratories. In the future, this work can be extended to determine the theoretical statistic and weight performances of different types of frequency standards quantitatively for time-keeping laboratories under both ideal and non-ideal conditions, providing a theoretical basis for improving the design of ensemble time scale algorithms. In the appendix, a method of obtaining the experimental variances and probability density functions (PDFs) of these two statistics is additionally proposed. The two-sample Kolmogorov–Smirnov test is presented to compare the experimental and theoretical PDFs of an example.
{"title":"Determination of Mathematical Expectations of Two Weighting Statistics for Ensemble Time Scales","authors":"Yiwei Wu, Siran Liu","doi":"10.1088/1681-7575/ad02a0","DOIUrl":"https://doi.org/10.1088/1681-7575/ad02a0","url":null,"abstract":"Abstract The Bureau International des Poids et Mesures uses the ALGOS algorithm to generate the Echelle Atomique Libre. The original and new ALGOS weighting algorithms employ two different statistics to calculate the weights, resulting in different experimental phenomena. These two statistics are believed to be the keys to analyzing these experimental phenomena, because the statistical characteristics (e.g. the mathematical expectations and variances) of the statistics completely determine the statistical characteristics of the weights, and subsequently the experimental phenomena. The core work conducted in this study is to derive the analytical expressions of the mathematical expectations of these two statistics under ideal conditions and to validate them empirically. This paper provides a theoretical analysis of these expressions and discusses the relationships between them and the mathematical expectations of the Allan variances. These expressions theoretically reveal the reasons behind the experimental phenomena, especially why hydrogen masers are assigned lower weights in the original ALGOS weighting algorithm but higher weights in the new one. According to the derivation process, these analytical expressions are universally applicable and can also be applied to time-keeping laboratories. In the future, this work can be extended to determine the theoretical statistic and weight performances of different types of frequency standards quantitatively for time-keeping laboratories under both ideal and non-ideal conditions, providing a theoretical basis for improving the design of ensemble time scale algorithms. In the appendix, a method of obtaining the experimental variances and probability density functions (PDFs) of these two statistics is additionally proposed. The two-sample Kolmogorov–Smirnov test is presented to compare the experimental and theoretical PDFs of an example.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"28 59","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135765044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.1088/1681-7575/acfe13
Chunguang Liu, Can Wang, Zhongli Zhang, Zhenghao Lin, Miaolin Feng
Abstract We utilized numerical methods to analyze the characteristics of the piston-cylinder assembly of a controlled-clearance piston gauge. The piston gauge was able to measure liquid pressure from 100 MPa to 1500 MPa with the relative expanded uncertainty of 0.02% ( k = 3). We established a finite element model to solve the stress and strain of the structural problem. The effective areas were calculated based on Dadson’s formula using the converged solutions of the clearance and the pressure distribution within the distorted piston-cylinder engagement gap that were iteratively determined by the finite element model and a fluid mechanics model with pressure-dependent fluid’s properties. Results were compared to the effective areas calculated by the modified Heydemann–Welch model based on experimental data, and the relative differences were less than 0.02%. We found sharp declines of the clearance and pressure distribution near the exit of the piston-cylinder engagement gap, which may lead to wearing during long-time operation at high pressures. Numerical results indicated non-linear relationship between jacket pressure and the cubic root of piston fall speed, which was traditionally considered as linear. The stall jacket pressure obtained by cubic (instead of linear) fitting extrapolation was found more close to the ones determined directly by the finite element model. Numerical results also found non-linear relationships among jacket pressure, measuring pressure, jacket pressure distortion coefficient.
{"title":"Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method","authors":"Chunguang Liu, Can Wang, Zhongli Zhang, Zhenghao Lin, Miaolin Feng","doi":"10.1088/1681-7575/acfe13","DOIUrl":"https://doi.org/10.1088/1681-7575/acfe13","url":null,"abstract":"Abstract We utilized numerical methods to analyze the characteristics of the piston-cylinder assembly of a controlled-clearance piston gauge. The piston gauge was able to measure liquid pressure from 100 MPa to 1500 MPa with the relative expanded uncertainty of 0.02% ( k = 3). We established a finite element model to solve the stress and strain of the structural problem. The effective areas were calculated based on Dadson’s formula using the converged solutions of the clearance and the pressure distribution within the distorted piston-cylinder engagement gap that were iteratively determined by the finite element model and a fluid mechanics model with pressure-dependent fluid’s properties. Results were compared to the effective areas calculated by the modified Heydemann–Welch model based on experimental data, and the relative differences were less than 0.02%. We found sharp declines of the clearance and pressure distribution near the exit of the piston-cylinder engagement gap, which may lead to wearing during long-time operation at high pressures. Numerical results indicated non-linear relationship between jacket pressure and the cubic root of piston fall speed, which was traditionally considered as linear. The stall jacket pressure obtained by cubic (instead of linear) fitting extrapolation was found more close to the ones determined directly by the finite element model. Numerical results also found non-linear relationships among jacket pressure, measuring pressure, jacket pressure distortion coefficient.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.1088/1681-7575/ad00bf
Peter J Mohr, Eric Shirley, William D Phillips, Michael Trott
Abstract We reply to a Comment on our paper ‘On the dimension of angles and their units’ by addressing concerns expressed in it about the topic of frequencies.
我们通过解决其中表达的关于频率主题的关注来回复对我们的论文“关于角度的维度及其单位”的评论。
{"title":"Reply to Comment on ‘On the dimension of angles and their units’","authors":"Peter J Mohr, Eric Shirley, William D Phillips, Michael Trott","doi":"10.1088/1681-7575/ad00bf","DOIUrl":"https://doi.org/10.1088/1681-7575/ad00bf","url":null,"abstract":"Abstract We reply to a Comment on our paper ‘On the dimension of angles and their units’ by addressing concerns expressed in it about the topic of frequencies.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.1088/1681-7575/acff74
Boris B Khlevnoy, I Grigoryeva
Abstract The furnace effect of the rhenium–carbon (Re–C) high-temperature fixed point was experimentally estimated by comparing the point-of-inflection temperature of the melting plateau demonstrated by the same Re–C cell in three furnaces of different dimensions. Two cells with the same outer size but different blackbody cavity designs were used. After corrections of the measured temperature for the size-of-source effect and the pyrometer stability, the furnace effect, estimated as the maximum change of the Re–C temperature from furnace to furnace, was found to be 0.094 K for the ‘best’ realisation of the fixed point. For the ‘normal’ realisation, additional components of the furnace effect, associated with non-optimal use of the fixed-point cell and furnace, were considered. The uncertainty components of the Re–C fixed point realisation associated with the furnace effect were estimated to be 0.060 K and 0.110 K for the best and normal cases, respectively.
{"title":"Furnace Effect for the Re-C Fixed Point","authors":"Boris B Khlevnoy, I Grigoryeva","doi":"10.1088/1681-7575/acff74","DOIUrl":"https://doi.org/10.1088/1681-7575/acff74","url":null,"abstract":"Abstract The furnace effect of the rhenium–carbon (Re–C) high-temperature fixed point was experimentally estimated by comparing the point-of-inflection temperature of the melting plateau demonstrated by the same Re–C cell in three furnaces of different dimensions. Two cells with the same outer size but different blackbody cavity designs were used. After corrections of the measured temperature for the size-of-source effect and the pyrometer stability, the furnace effect, estimated as the maximum change of the Re–C temperature from furnace to furnace, was found to be 0.094 K for the ‘best’ realisation of the fixed point. For the ‘normal’ realisation, additional components of the furnace effect, associated with non-optimal use of the fixed-point cell and furnace, were considered. The uncertainty components of the Re–C fixed point realisation associated with the furnace effect were estimated to be 0.060 K and 0.110 K for the best and normal cases, respectively.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-16DOI: 10.1088/1681-7575/acffcb
Yoshiro Yamada, Subrena Harris, Evangelos Theocharous, Michael Hayes
Abstract A new temperature calibration scheme was proposed and implemented on the National Physical Laboratory infrared radiometer Absolute Measurements of Blackbody Emitted Radiance (AMBER) operating in the wavelength range from 9 µm to 11 µm and equipped with a cryogenically cooled mercury cadmium telluride detector. The scheme involves measurements of the relative spectral responsivity of the filter radiometer including the spectral transmittance of the window and lens. It requires calibration at two reference temperatures, but does not involve measurement of the zero-radiance signal. The scheme uses a Ga-point blackbody as one reference point, and a variable temperature blackbody source at close to −30 °C with its temperature measured with a standard platinum resistance thermometer as the other. The measured temperature was compared using the variable temperature blackbody as the source against the temperature measured by the standard platinum resistance thermometer and agreement within the uncertainties was confirmed at intermediate temperatures. The scheme has the advantage that it makes full use of the small uncertainty realised by the fixed-point blackbody. The scheme was successfully implemented in an international comparison of sea surface temperature measuring radiometers where AMBER served to provide the reference.
{"title":"A novel radiometric calibration of infrared thermometer","authors":"Yoshiro Yamada, Subrena Harris, Evangelos Theocharous, Michael Hayes","doi":"10.1088/1681-7575/acffcb","DOIUrl":"https://doi.org/10.1088/1681-7575/acffcb","url":null,"abstract":"Abstract A new temperature calibration scheme was proposed and implemented on the National Physical Laboratory infrared radiometer Absolute Measurements of Blackbody Emitted Radiance (AMBER) operating in the wavelength range from 9 µm to 11 µm and equipped with a cryogenically cooled mercury cadmium telluride detector. The scheme involves measurements of the relative spectral responsivity of the filter radiometer including the spectral transmittance of the window and lens. It requires calibration at two reference temperatures, but does not involve measurement of the zero-radiance signal. The scheme uses a Ga-point blackbody as one reference point, and a variable temperature blackbody source at close to −30 °C with its temperature measured with a standard platinum resistance thermometer as the other. The measured temperature was compared using the variable temperature blackbody as the source against the temperature measured by the standard platinum resistance thermometer and agreement within the uncertainties was confirmed at intermediate temperatures. The scheme has the advantage that it makes full use of the small uncertainty realised by the fixed-point blackbody. The scheme was successfully implemented in an international comparison of sea surface temperature measuring radiometers where AMBER served to provide the reference.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136078068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-16DOI: 10.1088/1681-7575/acff75
Kyungmin Jo, Youngran Lim, Kyoung-Seok Lee, Euijin Hwang
Abstract Coulometry is used to realize the definition of the mole and enables the direct determination of the purity of high-purity substances that are used as standards for other relative measurements with very small measurement uncertainty. However, despite several studies reporting the development of accurate and precise coulometry systems, there is a lack of detailed description of the system and systematic evaluation of the measurement uncertainty arising from the system. In this study, coulometry systems constructed at the Korea Research Institute of Standards and Science (KRISS) are described in detail and the uncertainties associated with these systems are systematically evaluated using a bottom-up approach. The relative expanded uncertainty resulting from the measurement system for the amount-of-substance content of acid in high-purity potassium hydrogen phthalate is approximately 0.0005%. The performance of the KRISS coulometry systems has been verified through several international comparisons and comparative measurements using certified reference materials.
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