Pub Date : 2024-01-30DOI: 10.1088/1681-7575/ad1e37
J P Scott, R M Potvliege, D Carty, M P A Jones
We consider the potential use of optical traps for precision measurements in atomic hydrogen (H). Using an implicit summation method, we calculate the atomic polarisability, the rates of elastic/inelastic scattering and the ionisation rate in the wavelength range (395–1000) nm. We extend previous work to predict three new magic wavelengths for the 1S–2S transition. At the magic wavelengths, the 1S–2S transition is unavoidably and significantly broadened due to trap-induced ionisation associated with the high intensity required to trap the 1S state. However, we also find that this effect is partially mitigated by the low mass of H, which increases the trap frequency, enabling Lamb–Dicke confinement in shallow lattices. We find that a H optical lattice clock, free from the motional systematics which dominate in beam experiments, could operate with an intrinsic linewidth of the order of 1 kHz. Trap-induced losses are shown not to limit measurements of other transitions.
{"title":"Trap induced broadening in a potential hydrogen lattice clock","authors":"J P Scott, R M Potvliege, D Carty, M P A Jones","doi":"10.1088/1681-7575/ad1e37","DOIUrl":"https://doi.org/10.1088/1681-7575/ad1e37","url":null,"abstract":"We consider the potential use of optical traps for precision measurements in atomic hydrogen (H). Using an implicit summation method, we calculate the atomic polarisability, the rates of elastic/inelastic scattering and the ionisation rate in the wavelength range (395–1000) nm. We extend previous work to predict three new magic wavelengths for the 1S–2S transition. At the magic wavelengths, the 1S–2S transition is unavoidably and significantly broadened due to trap-induced ionisation associated with the high intensity required to trap the 1S state. However, we also find that this effect is partially mitigated by the low mass of H, which increases the trap frequency, enabling Lamb–Dicke confinement in shallow lattices. We find that a H optical lattice clock, free from the motional systematics which dominate in beam experiments, could operate with an intrinsic linewidth of the order of 1 kHz. Trap-induced losses are shown not to limit measurements of other transitions.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"41 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139755167","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 : 2024-01-19DOI: 10.1088/0026-1394/61/1a/07001
E Frahm, R Arias, M Maldonado, J Vargas, J J Mendoza, A Arredondo, M A Silvosa
<title>Main text</title>The 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 m<sup>3</sup>/h and 130 m<sup>3</sup>/h, 20 °C fluid temperature and 0.3 MPa line pressure. In order to estimate the uncertainties <italic toggle="yes">u</italic> <sub>TS</sub>, 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 <italic toggle="yes">E</italic> <sub>N</sub> values for the turbine meter were calculated based on PTB data, only. The <italic toggle="yes">E</italic> <sub>N</sub> 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 <italic toggle="yes">u</italic> <sub>TS</sub> was clearly dominated by the sensitivity to disturbed inflow conditions which leads to large values of <italic toggle="yes">u</italic> <sub>TS</sub> with > 0.20 %. Beside one calibration, all labs passed the <italic toggle="yes">E</italic> <sub>N</sub> criteria of ≤ 1.20. But, due to large values of <italic toggle="yes">u</italic> <sub>TS</sub>, the calibrations for all labs were evaluated as inconclusive. The evaluation criteria <italic toggle="yes">u</italic> <sub>comp</sub>/<italic toggle="yes">u</italic> <sub>base</sub> 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 <italic toggle="yes">u</italic> <sub>TS</sub> were estimated with 0.069 % at low flowrates and 0.033 % at high flowrates. Besides two calibrations, all laboratories complied with the <italic toggle="yes">E</italic> <sub>N</sub> criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria <italic toggle="yes">u</italic> <sub>comp</sub>/<italic toggle="yes">u</italic> <sub>base</sub> exceeded the critical value of 2.00 at one calibration, o
{"title":"Supplementary comparison SIM.M.FF-S9.2016 for water flow measurement","authors":"E Frahm, R Arias, M Maldonado, J Vargas, J J Mendoza, A Arredondo, M A Silvosa","doi":"10.1088/0026-1394/61/1a/07001","DOIUrl":"https://doi.org/10.1088/0026-1394/61/1a/07001","url":null,"abstract":"<title>Main text</title>The 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 m<sup>3</sup>/h and 130 m<sup>3</sup>/h, 20 °C fluid temperature and 0.3 MPa line pressure. In order to estimate the uncertainties <italic toggle=\"yes\">u</italic>\u0000<sub>TS</sub>, 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 <italic toggle=\"yes\">E</italic>\u0000<sub>N</sub> values for the turbine meter were calculated based on PTB data, only. The <italic toggle=\"yes\">E</italic>\u0000<sub>N</sub> 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 <italic toggle=\"yes\">u</italic>\u0000<sub>TS</sub> was clearly dominated by the sensitivity to disturbed inflow conditions which leads to large values of <italic toggle=\"yes\">u</italic>\u0000<sub>TS</sub> with > 0.20 %. Beside one calibration, all labs passed the <italic toggle=\"yes\">E</italic>\u0000<sub>N</sub> criteria of ≤ 1.20. But, due to large values of <italic toggle=\"yes\">u</italic>\u0000<sub>TS</sub>, the calibrations for all labs were evaluated as inconclusive. The evaluation criteria <italic toggle=\"yes\">u</italic>\u0000<sub>comp</sub>/<italic toggle=\"yes\">u</italic>\u0000<sub>base</sub> 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 <italic toggle=\"yes\">u</italic>\u0000<sub>TS</sub> were estimated with 0.069 % at low flowrates and 0.033 % at high flowrates. Besides two calibrations, all laboratories complied with the <italic toggle=\"yes\">E</italic>\u0000<sub>N</sub> criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria <italic toggle=\"yes\">u</italic>\u0000<sub>comp</sub>/<italic toggle=\"yes\">u</italic>\u0000<sub>base</sub> exceeded the critical value of 2.00 at one calibration, o","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"7 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509517","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 : 2024-01-19DOI: 10.1088/0026-1394/61/1a/08001
Kelvin Chun-wai Tse, Wai-hong Fung, Mala Khan, Soraya Sandoval Riquelme, Javier Vera, Li Xiao, Lu Hai, Ronald Cristancho, Adriana Rodriguez, Diego A Garzon Z , Carlos Andres España, Elias Kakoulides, G Karanikolopoulos, E Stathoudaki, V Schoina, Christine Elishian, Isna Komalasari, Luigi Bergamaschi, Giancarlo D'Agostino, Marco di Luzio, Shin-ichi Miyashita, Maria-del-Rocio Arvizu-Torres, Emilia Vasileva-Veleva, Elmer Carrasco, Alleni T Junsay, Michał Strzelec, Richard Shin, Radojko Jaćimović, Milena Horvat, Darja Mazej, Adna Alilović, Tea Zuliani, Angelique Botha, Maré Linsky, Nunnapus Laitip, Ramiro Pérez Zambra, Romina Napoli
Main textSeafood is one of the major food resources for human consumption in the world. The CODEX Alimentarius Commission and many jurisdictions have set maximum levels of metallic contaminants in seafood. The use of reliable methods for measurement of metallic contaminants is important in safeguarding the quality of these products and public health.The Supplementary Comparison APMP.QM-S19: Toxic Elements in Seafood was coordinated by the Government Laboratory, Hong Kong, China (GLHK). Four measurands (arsenic, cadmium, mercury and lead) in seafood were chosen. The last CCQM or RMO key comparison / supplementary comparison in the area of metallic contaminants in seafood was organized by GLHK in 2011 (APMP.QM-S5). Hence, it was timely to organize another comparison that covers different measurands. This Supplementary Comparison (APMP.QM-S19) offers different analytical challenges (e.g. in analysis of mercury and a different range of measurands) as compared to the previous comparison. Moreover, it enabled National Metrology Institutes / Designated Institutes (NMIs/DIs) that did not participate in the previous comparisons to demonstrate their measurement competencies.Nineteen institutes participated in APMP.QM-S19. Most participating NMIs/DIs employed microwave-assisted acid digestion for sample dissolution. Inductively coupled plasma mass spectrometry (ICP-MS), including triple quadrupole and sector field, were the most commonly used instrumental techniques. Results of all participating NMIs/DIs were evaluated against the supplementary comparison reference value (SCRV). The SCRV and associated uncertainty were determined from results of NMIs/DIs that participated in the supplementary comparison using methods with demonstrated metrological traceability. Median was used as estimator of the SCRVs. For arsenic, the SCRV was 1.342 mg/kg calculated from 15 participating NMIs/DIs. For arsenic, cadmium, mercury and lead, the SCRVs were 1.342 mg/kg, 0.3630 mg/kg, 0.1230 mg/kg and 0.4101 mg/kg, respectively, calculated from 15, 14, 13 and 11 participating NMIs/DIs.Participating NMIs/DIs that have successfully participated in APMP.QM-S19 have demonstrated measurement capabilities in determining inorganic elements, in a mass fraction range from 0.02 mg/kg to 50 mg/kg in high organic content matrix, including seafood of animal origin and high protein food.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).
{"title":"APMP.QM-S19: Toxic elements in seafood","authors":"Kelvin Chun-wai Tse, Wai-hong Fung, Mala Khan, Soraya Sandoval Riquelme, Javier Vera, Li Xiao, Lu Hai, Ronald Cristancho, Adriana Rodriguez, Diego A Garzon Z , Carlos Andres España, Elias Kakoulides, G Karanikolopoulos, E Stathoudaki, V Schoina, Christine Elishian, Isna Komalasari, Luigi Bergamaschi, Giancarlo D'Agostino, Marco di Luzio, Shin-ichi Miyashita, Maria-del-Rocio Arvizu-Torres, Emilia Vasileva-Veleva, Elmer Carrasco, Alleni T Junsay, Michał Strzelec, Richard Shin, Radojko Jaćimović, Milena Horvat, Darja Mazej, Adna Alilović, Tea Zuliani, Angelique Botha, Maré Linsky, Nunnapus Laitip, Ramiro Pérez Zambra, Romina Napoli","doi":"10.1088/0026-1394/61/1a/08001","DOIUrl":"https://doi.org/10.1088/0026-1394/61/1a/08001","url":null,"abstract":"<title>Main text</title>Seafood is one of the major food resources for human consumption in the world. The CODEX Alimentarius Commission and many jurisdictions have set maximum levels of metallic contaminants in seafood. The use of reliable methods for measurement of metallic contaminants is important in safeguarding the quality of these products and public health.The Supplementary Comparison APMP.QM-S19: Toxic Elements in Seafood was coordinated by the Government Laboratory, Hong Kong, China (GLHK). Four measurands (arsenic, cadmium, mercury and lead) in seafood were chosen. The last CCQM or RMO key comparison / supplementary comparison in the area of metallic contaminants in seafood was organized by GLHK in 2011 (APMP.QM-S5). Hence, it was timely to organize another comparison that covers different measurands. This Supplementary Comparison (APMP.QM-S19) offers different analytical challenges (e.g. in analysis of mercury and a different range of measurands) as compared to the previous comparison. Moreover, it enabled National Metrology Institutes / Designated Institutes (NMIs/DIs) that did not participate in the previous comparisons to demonstrate their measurement competencies.Nineteen institutes participated in APMP.QM-S19. Most participating NMIs/DIs employed microwave-assisted acid digestion for sample dissolution. Inductively coupled plasma mass spectrometry (ICP-MS), including triple quadrupole and sector field, were the most commonly used instrumental techniques. Results of all participating NMIs/DIs were evaluated against the supplementary comparison reference value (SCRV). The SCRV and associated uncertainty were determined from results of NMIs/DIs that participated in the supplementary comparison using methods with demonstrated metrological traceability. Median was used as estimator of the SCRVs. For arsenic, the SCRV was 1.342 mg/kg calculated from 15 participating NMIs/DIs. For arsenic, cadmium, mercury and lead, the SCRVs were 1.342 mg/kg, 0.3630 mg/kg, 0.1230 mg/kg and 0.4101 mg/kg, respectively, calculated from 15, 14, 13 and 11 participating NMIs/DIs.Participating NMIs/DIs that have successfully participated in APMP.QM-S19 have demonstrated measurement capabilities in determining inorganic elements, in a mass fraction range from 0.02 mg/kg to 50 mg/kg in high organic content matrix, including seafood of animal origin and high protein food.To reach the main text of this paper, click on <ext-link xlink:href=\"https://www.bipm.org/documents/d/guest/apmp-qm-s19\" xlink:type=\"simple\">Final Report</ext-link>. Note that this text is that which appears in Appendix B of the BIPM key comparison database <ext-link xlink:href=\"https://www.bipm.org/kcdb/\" xlink:type=\"simple\">https://www.bipm.org/kcdb/</ext-link>.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).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"19 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509074","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 : 2024-01-19DOI: 10.1088/0026-1394/61/1a/01001
A Widarta
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).
{"title":"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","authors":"A Widarta","doi":"10.1088/0026-1394/61/1a/01001","DOIUrl":"https://doi.org/10.1088/0026-1394/61/1a/01001","url":null,"abstract":"<title>Main text</title>This 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 <ext-link xlink:href=\"https://www.bipm.org/documents/d/guest/ccem-rf-k26\" xlink:type=\"simple\">Final Report</ext-link>. Note that this text is that which appears in Appendix B of the BIPM key comparison database <ext-link xlink:href=\"https://www.bipm.org/kcdb/\" xlink:type=\"simple\">https://www.bipm.org/kcdb/</ext-link>.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).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"15 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509198","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 : 2024-01-19DOI: 10.1088/0026-1394/61/1a/06001
N J Roberts, N A Horwood, Z Vykydal, H Park, J Kim, W W Pereira, E S da Fonseca, C Thiam, Zhang Hui, M S Dewey, H P Mumm, H Harano, T Matsumoto, A Masuda, S Manabe, J P Archambault, N N Moiseev, A V Didyk
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).
{"title":"International comparison of measurements of neutron source emission rate (2016-2021) - CCRI(III)-K9.Cf.2016","authors":"N J Roberts, N A Horwood, Z Vykydal, H Park, J Kim, W W Pereira, E S da Fonseca, C Thiam, Zhang Hui, M S Dewey, H P Mumm, H Harano, T Matsumoto, A Masuda, S Manabe, J P Archambault, N N Moiseev, A V Didyk","doi":"10.1088/0026-1394/61/1a/06001","DOIUrl":"https://doi.org/10.1088/0026-1394/61/1a/06001","url":null,"abstract":"<title>Main text</title>Section III (neutron measurements) of the Comité Consultatif des Rayonnements Ionisants, CCRI, conducted a comparison of primary measurements of the neutron emission rate of a <sup>252</sup>Cf radionuclide source. A single <sup>252</sup>Cf 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 <sup>250</sup>Cf 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 <sup>3</sup>He 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 <ext-link xlink:href=\"https://www.bipm.org/documents/d/guest/ccri-iii-k9-cf-252-2016\" xlink:type=\"simple\">Final Report</ext-link>. Note that this text is that which appears in Appendix B of the BIPM key comparison database <ext-link xlink:href=\"https://www.bipm.org/kcdb/\" xlink:type=\"simple\">https://www.bipm.org/kcdb/</ext-link>.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).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"16 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509348","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 : 2024-01-09DOI: 10.1088/1681-7575/ad1ca9
Jisun Lee, Jay Hyoun Kwon, Chang Yong Park, Huidong Kim, In-Mook Choi, Jin Wan Chung, Won-Kyu Lee
Relativistic redshift correction should be accurately considered in frequency comparisons between frequency standards. In this study, we evaluated the relativistic redshift at Korea Research Institute of Standards and Science (KRISS) using three different methods, depending on whether the approach was traditional or modern or whether the geopotential model was global or local. The results of the three methods agreed well with one another, and the height of an Yb optical lattice clock (KRISS-Yb1) was determined to be 75.15 m with an uncertainty of 0.04 m with respect to the conventionally adopted equipotential surface W_0^CGPM, the value of which is defined to be 62 636 856.0 m2s-2. Accordingly, the relativistic redshift of KRISS-Yb1 was evaluated to be 8.193(4) × 10−15. These data are applicable to the frequency standards at KRISS, one of which regularly participates in the calibration of the International Atomic Time (TAI).
{"title":"Evaluation of the relativistic redshift in frequency standards at KRISS","authors":"Jisun Lee, Jay Hyoun Kwon, Chang Yong Park, Huidong Kim, In-Mook Choi, Jin Wan Chung, Won-Kyu Lee","doi":"10.1088/1681-7575/ad1ca9","DOIUrl":"https://doi.org/10.1088/1681-7575/ad1ca9","url":null,"abstract":"\u0000 Relativistic redshift correction should be accurately considered in frequency comparisons between frequency standards. In this study, we evaluated the relativistic redshift at Korea Research Institute of Standards and Science (KRISS) using three different methods, depending on whether the approach was traditional or modern or whether the geopotential model was global or local. The results of the three methods agreed well with one another, and the height of an Yb optical lattice clock (KRISS-Yb1) was determined to be 75.15 m with an uncertainty of 0.04 m with respect to the conventionally adopted equipotential surface W_0^CGPM, the value of which is defined to be 62 636 856.0 m2s-2. Accordingly, the relativistic redshift of KRISS-Yb1 was evaluated to be 8.193(4) × 10−15. These data are applicable to the frequency standards at KRISS, one of which regularly participates in the calibration of the International Atomic Time (TAI).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"21 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443667","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 : 2024-01-08DOI: 10.1088/1681-7575/ad1bfb
Kang Lan, Lide Fang, Ying Wang, Zhiru Kang, Suli Sang
For all the subranges above 0.01 ℃, other than the interpolation between the triple point of water (TPW) to the melting point of gallium, temperatures on the ITS-90 are specified without the melting point of gallium. This study suggests a new interpolation equation in the subrange from the triple point of water to the freezing point of indium which is a polynomial of fractional third order with two coefficients to be determined by the measuring values of standard platinum resistance thermometers (SPRTs)’ resistance ratios at the melting point of gallium (WGa) and at the freezing point of indium (WIn). A sample set of 30 SPRTs from various countries and laboratories is used to quantify the comparisons between this new interpolation and the ITS-90. Analyses show that the reproducibility is significantly improved compared with the ITS-90 in the same subrange. The peak value of overlapping subrange inconsistencies (SRI) from TPW to the melting point of gallium is reduced from 0.91 mK to 0.21 mK. Both the mean and standard deviation of the SRI peak values for the new equation decrease by approximately a factor of four compared to those of the ITS-90 (mean decreasing form 0.20 mK to 0.05 mK and standard deviation decreasing form 0.32 mK to 0.07 mK). Type 3 non-uniqueness (NU3) determinations of the same subrange have also been looked into with a data set of four SPRTs compared in thermostatic baths using a copper block and the results show that NU3 scales down from a range -0.15 mK to 0.25 mK of the ITS-90 to -0.10 mK to 0.15 mK of the new interpolation equation. Propagation of Uncertainties investigation shows that the new equation inflates merely 7% the measurement uncertainties of fixed points in a relatively short interval from 30 ℃ to 60 ℃.
{"title":"A New Interpolation Equation in the ITS-90 Subrange from the Triple Point of Water to the Freezing Point of Indium","authors":"Kang Lan, Lide Fang, Ying Wang, Zhiru Kang, Suli Sang","doi":"10.1088/1681-7575/ad1bfb","DOIUrl":"https://doi.org/10.1088/1681-7575/ad1bfb","url":null,"abstract":"\u0000 For all the subranges above 0.01 ℃, other than the interpolation between the triple point of water (TPW) to the melting point of gallium, temperatures on the ITS-90 are specified without the melting point of gallium. This study suggests a new interpolation equation in the subrange from the triple point of water to the freezing point of indium which is a polynomial of fractional third order with two coefficients to be determined by the measuring values of standard platinum resistance thermometers (SPRTs)’ resistance ratios at the melting point of gallium (WGa) and at the freezing point of indium (WIn). A sample set of 30 SPRTs from various countries and laboratories is used to quantify the comparisons between this new interpolation and the ITS-90. Analyses show that the reproducibility is significantly improved compared with the ITS-90 in the same subrange. The peak value of overlapping subrange inconsistencies (SRI) from TPW to the melting point of gallium is reduced from 0.91 mK to 0.21 mK. Both the mean and standard deviation of the SRI peak values for the new equation decrease by approximately a factor of four compared to those of the ITS-90 (mean decreasing form 0.20 mK to 0.05 mK and standard deviation decreasing form 0.32 mK to 0.07 mK). Type 3 non-uniqueness (NU3) determinations of the same subrange have also been looked into with a data set of four SPRTs compared in thermostatic baths using a copper block and the results show that NU3 scales down from a range -0.15 mK to 0.25 mK of the ITS-90 to -0.10 mK to 0.15 mK of the new interpolation equation. Propagation of Uncertainties investigation shows that the new equation inflates merely 7% the measurement uncertainties of fixed points in a relatively short interval from 30 ℃ to 60 ℃.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"36 22","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139448041","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 : 2024-01-04DOI: 10.1088/1681-7575/ad1af1
Jungjae Park, Yoonhee Jang, Jonghan Jin
The electro-optic comb (EO comb) with a relatively wide mode spacing of 25 GHz can be resolved into individual frequency modes with a commercially available high-resolution spectrometer. The EO comb has numerous discrete frequency modes, which can serve as a light source for a monochromatic laser interferometer to realize the meter. In this study, a method for measuring the absolute distances based on the multi-wavelength interferometer principle is proposed and demonstrated by simultaneously implementing 102 monochromatic laser interferometers using an EO comb. A phase shifting technique was used to determine the phase for each frequency mode by precisely translating a reference mirror with a constant interval. The phases of the interference signals for 102 stabilized individual frequency modes were measured by applying the model-based analysis on the phase-shifted interference signals. The absolute distance can be determined using phase values of a wavelength set corresponding to five to seven randomly selected frequency modes. In this study, the absolute distances for round-trip distances of 166 mm and 1316 mm were measured and the measurement uncertainty of each distance was evaluated. Through the uncertainty analysis of the distance measurement, the combined uncertainties of the measured distances in a short and long ranges were evaluated to be 30.1 nm and 211.1 nm, respectively. In addition, for each distance, the consistent measurement results of absolute distances were obtained through four different wavelength sets, which show the flexibility of wavelength selection in this work.
{"title":"Length measurement based on multi-wavelength interferometry using numerous stabilized frequency modes of an optical comb","authors":"Jungjae Park, Yoonhee Jang, Jonghan Jin","doi":"10.1088/1681-7575/ad1af1","DOIUrl":"https://doi.org/10.1088/1681-7575/ad1af1","url":null,"abstract":"\u0000 The electro-optic comb (EO comb) with a relatively wide mode spacing of 25 GHz can be resolved into individual frequency modes with a commercially available high-resolution spectrometer. The EO comb has numerous discrete frequency modes, which can serve as a light source for a monochromatic laser interferometer to realize the meter. In this study, a method for measuring the absolute distances based on the multi-wavelength interferometer principle is proposed and demonstrated by simultaneously implementing 102 monochromatic laser interferometers using an EO comb. A phase shifting technique was used to determine the phase for each frequency mode by precisely translating a reference mirror with a constant interval. The phases of the interference signals for 102 stabilized individual frequency modes were measured by applying the model-based analysis on the phase-shifted interference signals. The absolute distance can be determined using phase values of a wavelength set corresponding to five to seven randomly selected frequency modes. In this study, the absolute distances for round-trip distances of 166 mm and 1316 mm were measured and the measurement uncertainty of each distance was evaluated. Through the uncertainty analysis of the distance measurement, the combined uncertainties of the measured distances in a short and long ranges were evaluated to be 30.1 nm and 211.1 nm, respectively. In addition, for each distance, the consistent measurement results of absolute distances were obtained through four different wavelength sets, which show the flexibility of wavelength selection in this work.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"31 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386938","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}
We report the realization of the closed-loop operation of an optical lattice clock based on 87Sr atoms. A cavity-stabilized 698 nm laser is used to probe the 1S0→3P0 clock transition of strontium atoms trapped in optical lattices. Therein, we obtain a Fourier-limited Rabi spectrum with 0.6 Hz linewidth. The two transitions from mF=±9/2 ground states are alternatively interrogated to realize the closed-loop operation of the clock, and the clock laser light is frequency-stabilized to the center of the two transitions. Based on the interleaved measurement, the frequency instability of a single optical clock is optimized for the Dick effect, which is demonstrated to be 4.5×10−16/τ , with τ being the averaging time for measurement. Further, we build another similar setup of the strontium lattice clock, which is used for the asynchronous comparison between the two clocks, where the stability is measured as 2.1×10−18 at 47 000 s. Moreover, we carefully calibrate the systematic effects of the Sr1 optical clock, and the total uncertainty is evaluated as 4.4×10−18 .
{"title":"A strontium lattice clock with both stability and uncertainty below 5×10−18","authors":"Jie Li, Xing-Yang Cui, Zhi-Peng Jia, De-Quan Kong, Hai-Wei Yu, Xian-Qing Zhu, Xiao-Yong Liu, De-Zhong Wang, Xiang Zhang, Xin-Yun Huang, Ming-Yi Zhu, Yu-Meng Yang, Yi Hu, Xiang-Pei Liu, Xiaomin Zhai, Peng Liu, Xiao Jiang, Ping Xu, Han-Ning Dai, Yuao Chen, Jian-Wei Pan","doi":"10.1088/1681-7575/ad1a4c","DOIUrl":"https://doi.org/10.1088/1681-7575/ad1a4c","url":null,"abstract":"We report the realization of the closed-loop operation of an optical lattice clock based on 87Sr atoms. A cavity-stabilized 698 nm laser is used to probe the 1S0→3P0 clock transition of strontium atoms trapped in optical lattices. Therein, we obtain a Fourier-limited Rabi spectrum with 0.6 Hz linewidth. The two transitions from mF=±9/2 ground states are alternatively interrogated to realize the closed-loop operation of the clock, and the clock laser light is frequency-stabilized to the center of the two transitions. Based on the interleaved measurement, the frequency instability of a single optical clock is optimized for the Dick effect, which is demonstrated to be 4.5×10−16/τ , with τ being the averaging time for measurement. Further, we build another similar setup of the strontium lattice clock, which is used for the asynchronous comparison between the two clocks, where the stability is measured as 2.1×10−18 at 47 000 s. Moreover, we carefully calibrate the systematic effects of the Sr1 optical clock, and the total uncertainty is evaluated as 4.4×10−18 .","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"48 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451731","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 : 2024-01-01DOI: 10.1088/1681-7575/ad90e6
Jared H Strait, Richard A Allen
We present an optical scheme to simultaneously characterize the cross-axis and rotational parasitic motions of a long-stroke shaker. By leveraging the geometric properties of a corner cube retroreflector mounted on the shaker load table, we independently sample pitch, yaw, and horizontal and vertical displacements with sampling rates above 10 kHz. We have applied our optical apparatus to a 400-mm-stroke shaker operated from 0.1 Hz to 100 Hz and present two forms of analysis: (A) Frequency-domain data for the four measured parasitic degrees of freedom, with the resulting implications for accelerometer calibration uncertainties, and (B) extracted trajectories of the shaker table, allowing visualization of the bowed linear guide below 0.5 Hz and higher harmonics and hysteresis above 10 Hz. Our findings demonstrate our optical measurement scheme to be an effective tool for the characterization of parasitic motion for long-stroke shakers. As an example, we determine the "gravity error" in accelerometer calibration with our shaker to be (1.3 ± 0.1) % times the acceleration amplitude at 0.1 Hz, providing a correction to reduce uncertainty from this effect by an order of magnitude.
{"title":"Optical Characterization of Parasitic Motion in a Long-Stroke Shaker.","authors":"Jared H Strait, Richard A Allen","doi":"10.1088/1681-7575/ad90e6","DOIUrl":"10.1088/1681-7575/ad90e6","url":null,"abstract":"<p><p>We present an optical scheme to simultaneously characterize the cross-axis and rotational parasitic motions of a long-stroke shaker. By leveraging the geometric properties of a corner cube retroreflector mounted on the shaker load table, we independently sample pitch, yaw, and horizontal and vertical displacements with sampling rates above 10 kHz. We have applied our optical apparatus to a 400-mm-stroke shaker operated from 0.1 Hz to 100 Hz and present two forms of analysis: (A) Frequency-domain data for the four measured parasitic degrees of freedom, with the resulting implications for accelerometer calibration uncertainties, and (B) extracted trajectories of the shaker table, allowing visualization of the bowed linear guide below 0.5 Hz and higher harmonics and hysteresis above 10 Hz. Our findings demonstrate our optical measurement scheme to be an effective tool for the characterization of parasitic motion for long-stroke shakers. As an example, we determine the \"gravity error\" in accelerometer calibration with our shaker to be (1.3 ± 0.1) % times the acceleration amplitude at 0.1 Hz, providing a correction to reduce uncertainty from this effect by an order of magnitude.</p>","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"62 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12013252/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144032554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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