{"id":7882,"date":"2023-08-17T13:55:50","date_gmt":"2023-08-17T06:55:50","guid":{"rendered":"https:\/\/en.nimt.or.th\/?page_id=7882"},"modified":"2024-10-16T09:50:58","modified_gmt":"2024-10-16T02:50:58","slug":"dc-voltage-laboratory-jjvs","status":"publish","type":"page","link":"https:\/\/en.nimt.or.th\/?page_id=7882","title":{"rendered":"DC Voltage Laboratory (JJVS)"},"content":{"rendered":"
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\n\t\t\t\t\t\tIntroduction\t\t\t\t\t\t<\/h1>\n\t\t\t\t\t\t<\/div>\n<\/div><\/div>
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The NIMT Voltage laboratory develops and maintains national standards for voltage measurement. These include primary voltage standard , Josephson Junction Voltage Standard (JJVS), which based on quantum effects. The most familiar quantum standard is the Josephson array voltage standard. For two superconductors separated by a very thin insolating layer (a so-called Josephson junction), a DC voltage difference will occur when an RF bias current is supplied. The voltage V<\/i> will only depend on the frequency f<\/i> of the supplied signal and on constants of nature:<\/p>\n

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where n<\/i> is a tunable integer number that can be tuned using for example a DC bias current, e<\/i> is the electron charge and h<\/i> is Planck\u2019s constant. This voltage is known within a relative uncertainty of 10-9, since frequency can be determined very accurately (relative uncertainty better than 10-15).<\/p>\n

The newest voltage standards that are optimized for dc voltage measurements at NIMT, called programmable Josephson voltage standard (PJVS). It is a voltage primary standard derived from frequency and the fundamental constant of the ratio between the electron charge (e<\/i>) and Planck's constant (h<\/i>) that is programmable and high accurate to support frontier research in the natural sciences, including quantum metrological triangle research and redefining the unit of mass, kg (redefinition of the kilogram), and can also be developed to measure AC voltage called AC Quantum Voltmeter.<\/p>\n<\/div>\n<\/div><\/div>

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Inter-Comparison<\/b><\/p>\n

Voltage laboratory was participated in 4 comparisons of DC voltage measurement:
\n\u25aa bilateral comparison with NMC, Singapore in 2010,
\n\u25aa APMP key comparison of DC Voltage at 1.018 V and 10 V (APMP.EM.BIPM-K11.3) in 2010,
\n\u25aa Bilateral Comparison of 1 V and 10 V Standards between the NIMT (Thailand) and the BIPM (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b) in October to December 2014, and
\n\u25aa Comparison of the Josephson Voltage Standards of the NIMT and the BIPM (part of the ongoing BIPM key comparison BIPM.EM-K10.b) in November 2015<\/p>\n<\/div>\n<\/div><\/div>

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on-site JVS comparison between BIPM and NIMT in 2015<\/strong><\/h2>\n

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The comparison of the Josephson array voltage standards between BIPM and NIMT of the BIPM.EM-K10.b comparison protocol were applied. Option B required the BIPM to provide a reference voltage for measurement by the NIMT using its Josephson voltage standard with its own measuring device. The final results were in good agreement within the combined relative standard uncertainty of 2.6\u00a0parts in 1010 for the nominal voltage of 10\u00a0V.<\/p>\n<\/div>\n<\/div><\/div>

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Josephson Junction voltage standard : JJVS <\/b><\/h1>\n

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Programmable Josephson Voltage Standard : PJVS<\/b><\/h1>\n

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The PJVS has had great success generating large output voltages by biasing the Josephson junctions with 70 GHz microwave signals. A single microwave signal is input to the superconducting integrated circuit where it is divided to bias 32 or 64 different JJ arrays. This on-chip division of the microwave signal is accomplished using multiple stages of microwave dividers. Dividers with modest bandwidth are sufficient because PJVSs use a single-frequency bias.<\/p>\n

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A Group of DC Reference standards<\/strong><\/h1>\n

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The voltage laboratory has installed a group of voltage standard equipment. To be used as a reference standard in transferring the accuracy of DC voltage to secondary standards, such as DC standard, calibrator and digital multimeter, etc. This voltage standard group consists of 4 DC voltage standard.<\/p>\n

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\n\t\t\t\t\t\tCalibration services\t\t\t\t\t\t<\/h1>\n\t\t\t\t\t\t<\/div>\n<\/div><\/div>
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\n\t\t\t\t\t\tStaff\t\t\t\t\t\t<\/h1>\n\t\t\t\t\t\t<\/div>\n<\/div><\/div>
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<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\n\t\t\t
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\n\t\t\t\t\t\tFS.1 Sittisak Pimsut\t\t\t\t\t<\/h5>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t
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Metrologist , Senior Professional
\nEmail<\/strong> : sittisak@nimt.or.th
\nTel.<\/strong> : 02-5775100 Ext. 1229<\/p>\n

Area of research\/expertise<\/b>
\n- Development of primary DC voltage standard base on the Josephson effect<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/li>\n\n\t\t\t\n\t\t\t\n\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t

<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\n\t\t\t
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\n\t\t\t\t\t\tDr. Yaowaret Pimsut\t\t\t\t\t<\/h5>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t
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Metrologist , Professional<\/strong>
\nEmail :<\/strong> yaowaret@nimt.or.th
\nTel.<\/strong> : 02-5775100 Ext.1229<\/p>\n

Area of research\/expertise<\/b>
\n- \u201cFour Terminal Pair Impedance Bridge based on two pulse-driven Josephson Arrays
\nand a Graphene Quantum Hall System\u201d<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/li>\n\n\t<\/ul>\n<\/div><\/div>

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\n\t\t\t\t\t\tRelated publications\/articles\t\t\t\t\t\t<\/h1>\n\t\t\t\t\t\t<\/div>\n<\/div><\/div>
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Selected publications<\/b><\/p>\n

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  1. S. Solve\u2020, R. Chayramy\u2020, M. Stock\u2020, S. Pimsut* and N. Rujirat*, \u201cComparison <\/i>of the Josephson Voltage <\/i>Standards of <\/i>the NIMT and the BIPM
    \n(part of the ongoing BIPM key comparison BIPM.EM-K10.b<\/i>)\u201d<\/i>, Metrologia, Volume 53, Technical Supplement, https:\/\/dx.doi.org\/10.1088\/0026-1394\/53\/1A\/01006<\/li>\n
  2. <\/i>S. Solve, R. Chayramy, M. Stock and S. Pimsut, \u201cBilateral <\/i>Comparison of <\/i>1<\/i> V and <\/i>10<\/i> V Standards between the NIMT (Thailand) and the BIPM, October to December <\/i>2014 (<\/i>part of the ongoing BIPM key comparison BIPM.EM-K<\/i>11.<\/i>a and <\/i>b)\u201d.<\/i><\/li>\n
  3. S Bauer, R Behr, R E Elmquist, M G\u00f6tz, J Herick, O Kieler, M Kruskopf, J Lee1, L Palafox, Y Pimsut and J Schurr, \u201cA four-terminal-pair Josephson impedance bridge combined with a graphene-quantized Hall resistance\u201d, <\/i>Measurement Science and Technology 32 (2021) 065007 (9pp), Published 31 March 2021<\/li>\n<\/ol>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"

    The NIMT Voltage laboratory develops and maintains national standards for voltage measurement. These include primary voltage standard , Josephson Junction Voltage Standard (JJVS), which based on quantum effects. The most familiar quantum standard is the Josephson array voltage standard. For two superconductors separated by a very thin insolating layer (a so-called Josephson junction), a DC […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-7882","page","type-page","status-publish","hentry","post"],"_links":{"self":[{"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/pages\/7882","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7882"}],"version-history":[{"count":15,"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/pages\/7882\/revisions"}],"predecessor-version":[{"id":9653,"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=\/wp\/v2\/pages\/7882\/revisions\/9653"}],"wp:attachment":[{"href":"https:\/\/en.nimt.or.th\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7882"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}