{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T10:48:51Z","timestamp":1770979731930,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,2,7]],"date-time":"2021-02-07T00:00:00Z","timestamp":1612656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003706","name":"Korea Research Institute of Standards and Science","doi-asserted-by":"publisher","award":["20011046"],"award-info":[{"award-number":["20011046"]}],"id":[{"id":"10.13039\/501100003706","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003706","name":"Korea Research Institute of Standards and Science","doi-asserted-by":"publisher","award":["20011270"],"award-info":[{"award-number":["20011270"]}],"id":[{"id":"10.13039\/501100003706","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2020R1A6A1A03047771"],"award-info":[{"award-number":["2020R1A6A1A03047771"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2020R1A6A3A0110054411"],"award-info":[{"award-number":["2020R1A6A3A0110054411"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We demonstrated spectral reflectometers for two types of reflectances, absolute and relative, of diffusely reflecting surfaces in directional-hemispherical geometry. Both are built based on the integrating sphere method with a Fourier-transform infrared spectrometer operating in a vacuum. The third Taylor method is dedicated to the reflectometer for absolute reflectance, by which absolute spectral diffuse reflectance scales of homemade reference plates are realized. With the reflectometer for relative reflectance, we achieved spectral diffuse reflectance scales of various samples including concrete, polystyrene, and salt plates by comparing against the reference standards. We conducted ray-tracing simulations to quantify systematic uncertainties and evaluated the overall standard uncertainty to be 2.18% (k = 1) and 2.99% (k = 1) for the absolute and relative reflectance measurements, respectively.<\/jats:p>","DOI":"10.3390\/s21041169","type":"journal-article","created":{"date-parts":[[2021,2,10]],"date-time":"2021-02-10T04:33:46Z","timestamp":1612931626000},"page":"1169","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Reflectometers for Absolute and Relative Reflectance Measurements in the Mid-IR Region at Vacuum"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4867-543X","authenticated-orcid":false,"given":"Jinhwa","family":"Gene","sequence":"first","affiliation":[{"name":"Institute of Quantum Systems (IQS), Chungnam National University, Daejeon 34134, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9944-8993","authenticated-orcid":false,"given":"Min Yong","family":"Jeon","sequence":"additional","affiliation":[{"name":"Institute of Quantum Systems (IQS), Chungnam National University, Daejeon 34134, Korea"},{"name":"Department of Physics, College of Natural Sciences, Chungnam National University, Daejeon 34134, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5065-5553","authenticated-orcid":false,"given":"Sun Do","family":"Lim","sequence":"additional","affiliation":[{"name":"Division of Physical Metrology, Korea Research Institute of Standards and Science, Daejeon 34113, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"940","DOI":"10.1364\/AO.15.000940","article-title":"Hemi-ellipsoidal mirror infrared reflectometer: Development and operation","volume":"15","author":"Wood","year":"1976","journal-title":"Appl. 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