{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T10:44:38Z","timestamp":1785926678592,"version":"3.56.0"},"reference-count":43,"publisher":"IOP Publishing","issue":"4","license":[{"start":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T00:00:00Z","timestamp":1785888000000},"content-version":"vor","delay-in-days":4,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T00:00:00Z","timestamp":1785888000000},"content-version":"tdm","delay-in-days":4,"URL":"https:\/\/iopscience.iop.org\/info\/page\/text-and-data-mining"}],"funder":[{"name":"U.S. Department of Commerce, National Institute of Standards and Technology","award":["70NANB24H050"],"award-info":[{"award-number":["70NANB24H050"]}]}],"content-domain":{"domain":["iopscience.iop.org"],"crossmark-restriction":false},"short-container-title":["Metrologia"],"published-print":{"date-parts":[[2026,8,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    The triple points of carbon dioxide (TP CO\n                    <jats:sub>2<\/jats:sub>\n                    ) and sulfur hexafluoride (TP SF\n                    <jats:sub>6<\/jats:sub>\n                    ) have been studied over the last decade as alternative fixed points to the triple point of mercury (TP Hg, 234.3156 K) on the International Temperature Scale of 1990 (ITS-90). NIST has been developing TP CO\n                    <jats:sub>2<\/jats:sub>\n                    and TP SF\n                    <jats:sub>6<\/jats:sub>\n                    cells to be employed as drop-in replacements for TP Hg cells for calibrations of standard platinum resistance thermometers (SPRTs). This work presents the results of the assessment of new immersion-type CO\n                    <jats:sub>2<\/jats:sub>\n                    and SF\n                    <jats:sub>6<\/jats:sub>\n                    triple point cells built at NIST and the results of their use in ITS-90 calibrations of long-stem SPRTs. It was demonstrated that a very well-controlled realization technique can result in measurements of the triple points of CO\n                    <jats:sub>2<\/jats:sub>\n                    and SF\n                    <jats:sub>6<\/jats:sub>\n                    within 25 \u03bcK and 75 \u03bcK of reproducibility, respectively, with estimated temperatures of 216.591 21(15) K and 223.556 22(33) K for\n                    <jats:italic>F<\/jats:italic>\n                    = 1, respectively. The large volume expansion of CO\n                    <jats:sub>2<\/jats:sub>\n                    and SF\n                    <jats:sub>6<\/jats:sub>\n                    upon melting in large immersion cells is responsible for a progressive head correction that increases the realization slopes of the triple points of CO\n                    <jats:sub>2<\/jats:sub>\n                    and SF\n                    <jats:sub>6<\/jats:sub>\n                    by 0.1 mK and 0.46 mK, respectively. Calibrations of two SPRTs on different ITS-90 subranges using either TP Hg, TP CO\n                    <jats:sub>2<\/jats:sub>\n                    or TP SF\n                    <jats:sub>6<\/jats:sub>\n                    cells showed that the interpolated temperatures using either triple point agreed within their realization uncertainties. These results demonstrate that both fixed points can be used as alternatives for the Hg TP in a future revision of the ITS-90.\n                  <\/jats:p>","DOI":"10.1088\/1681-7575\/ae81ba","type":"journal-article","created":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T22:47:52Z","timestamp":1782341272000},"page":"045004","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Realizations of the triple points of carbon dioxide and sulfur hexafluoride\u2014ITS-90 temperature determinations and interpolations"],"prefix":"10.1088","volume":"63","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9295-4757","authenticated-orcid":true,"given":"Klaus N","family":"Quelhas","sequence":"first","affiliation":[{"name":"Theiss Research"},{"name":"National Institute of Standards and Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0297-7161","authenticated-orcid":true,"given":"Richmond S","family":"Wang","sequence":"additional","affiliation":[{"name":"National Institute of Standards and Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6647-3933","authenticated-orcid":false,"given":"Andrea","family":"Peruzzi","sequence":"additional","affiliation":[{"name":"National Research Council of Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9979-9136","authenticated-orcid":true,"given":"Weston L","family":"Tew","sequence":"additional","affiliation":[{"name":"National Institute of Standards and Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"266","published-online":{"date-parts":[[2026,8,5]]},"reference":[{"key":"metae81babib1","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1088\/0026-1394\/27\/1\/002","type":"journal-article","article-title":"The international temperature scale of 1990 (ITS-90)","volume":"27","author":"Preston-thomas","year":"1990","journal-title":"Metrologia"},{"key":"metae81babib2","doi-asserted-by":"publisher","first-page":"1","DOI":"10.6028\/jres.123.013","type":"journal-article","article-title":"Realizations of the triple point of sulfur hexafluoride in transportable and refillable cells","volume":"123","author":"Tew","year":"2018","journal-title":"J. Res. Natl Inst. Stand. Technol."},{"key":"metae81babib3","type":"conference-proceedings","article-title":"Investigation to replace the triple point of Hg in the ITS-90","volume":"vol 9","author":"Kawamura","year":"2024"},{"key":"metae81babib4","doi-asserted-by":"publisher","DOI":"10.1088\/1681-7575\/ab451e","type":"journal-article","article-title":"Realization of the triple point of carbon dioxide evaluated by the ITS\u201390","volume":"57","author":"Kawamura","year":"2020","journal-title":"Metrologia"},{"key":"metae81babib5","doi-asserted-by":"publisher","first-page":"520","DOI":"10.1007\/s11018-023-02113-z","type":"journal-article","article-title":"Modernization of the international temperature scale ITS-90: triple point of carbon dioxide instead of triple point of mercury","volume":"65","author":"Okladnikov","year":"2022","journal-title":"Meas. 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Contribution of The National Institute of Standards and Technology is not subject to copyright in the USA. Published on behalf of BIPM by IOP Publishing Ltd","name":"copyright_information","label":"Copyright Information"},{"value":"2026-03-30","name":"date_received","label":"Date Received","group":{"name":"publication_dates","label":"Publication dates"}},{"value":"2026-06-24","name":"date_accepted","label":"Date Accepted","group":{"name":"publication_dates","label":"Publication dates"}},{"value":"2026-08-05","name":"date_epub","label":"Online publication date","group":{"name":"publication_dates","label":"Publication dates"}}]}}