CAD models now available for our temperature sensors

Given how small some cryogenic spaces can be, it’s often helpful to model the structure before starting the build. Over the years, we’ve received many requests from people looking for models of our temperature sensors. Now they are available and can be found under the Downloads tab for whichever sensor you’d like a model for. Source: Lakeshore…

Some predictions of a validated physical model of Pt–Rh thermocouple drift above 1200 ° C

A simple model was recently presented which relates the electromotive force (emf) drift rate of Pt–Rh thermoelements to the vapour pressure of Pt and Rh oxides. The model assumes that the evaporation of these oxides gives rise to a continuously changing concentration of Pt and Rh, at different rates along the length of the wires, which causes a change in the Seebeck coefficient. The model was tested by comparison with high precision measurements under comparable circumstances. By considering various thermocouples of…

Distribution identification and information loss in a measurement uncertainty network

Measurement uncertainty is an increasingly important consideration in many applications demanding extreme performance levels. In the era of the internet of things and 5G connectivity we can learn more about device performance by utilising the increasing amount of data produced. These data require appropriate information infrastructure to facilitate continuous updating of device performance knowledge. This paper presents the results of a study which NPL undertook with a leading test and measurement device manufacturer to examine how measurement uncertainty propagates through the…

Force AFRIMETS supplementary comparison AFRIMETS.M.F-S2

The Regional Metrology Organization AFRIMETS Technical Committee in Mass and related Quantities (TCM) Working Group Force (WGF) met in July 2018 in Enugu Nigeria during the 12th General Assembly (GA) and made a decision to carry out an AFRIMETS supplementary comparison for the unit of force. This comparison, named the AFRIMETS.M. F-S2 supplementary comparison, in the force range of 250 kN and 500 kN. This comparison was planned to demonstrate the degree of equivalence between the national standards of force and…

Finite element analysis of blackbody radiation environment for an ytterbium lattice clock operated at room temperature

The Stark shift due to blackbody radiation (BBR) is a key obstacle limiting the frequency uncertainty of optical lattice clocks. A well-characterized BBR environment is necessary to know exactly the temperature felt by the cold atoms. In our ytterbium clock, the lattice-trapped atoms are exposed to the thermal radiation of the surrounding vacuum chamber walls and optical windows. Calibrated platinum resistance temperature detectors are used to monitor the vacuum chamber temperature in real time. In order to obtain the effective temperature…

Survey of subrange inconsistency of long-stem standard platinum resistance thermometers

The subrange inconsistency (SRI) of a large ensemble of long-stem standard platinum resistance thermometers (SPRTs), representative of worldwide production, has been investigated for all pairs of ITS-90 overlapping subranges between 83.8058 K and 933.473 K. The results are reported in terms of various statistical parameters to facilitate their comparison with the results of different authors, although a statistical test, applied to one specific pair of subranges, supported a Gaussian distribution of the results and justified the subsequent use of the mean and standard…

Uncertainty in the mutual calibration method for the traceable thickness measurement of ultra-thin oxide films

Mutual calibration by a combination of a zero-offset method and a length-unit traceable method has been suggested as a promising approach to determine the traceable thickness of ultra-thin oxide films. However, the measurement uncertainty is somewhat complicated to calculate because the standard uncertainties from the two measurement methods and the linear regression process should be combined. In this study, the mutual calibration method to evaluate the film thickness and uncertainty of ultra-thin oxide films was investigated. The algorithm of the linear…

The value of stable, comparable and standardised measurement: enabling confidence in decision making for societal challenges

Making decisions that have broad societal and economic impact is extremely hard. This is especially true when the data upon which choices for future action are based are unstable or have uncertain provenance. This letter discusses the benefits of metrology, as the science of measurement, in providing data that is stable, comparable and produced using standardised methods, in enabling greater confidence in the decision-making process. A key part of this increased confidence is via providing input data with reduced uncertainty, thereby…

Key comparison BIPM.RI(I)-K4 of the absorbed dose to water standards of the BEV, Austria and the BIPM in 60 Co gamma radiation

A new key comparison of the standards for absorbed dose to water of the Bundesamt für Eich- und Vermessungswesen (BEV), Austria and the Bureau International des Poids et Mesures (BIPM) was carried out in the 60 Co radiation beam of the BIPM in July 2020. The comparison result, based on the calibration coefficients for two transfer standards and evaluated as a ratio of the BEV and the BIPM standards for absorbed dose to water, is 0.9997 with a combined standard uncertainty…

Final report on SIM.L.K1.2007.1 bilateral comparison (length) 2018-2019: calibration of gauge blocks by optical interferometry

This bilateral SIM key comparison on calibration of gauge blocks by interferometry (SIM.L-K1.2007.1) was carried out between CENAM (México) and INTI (Argentina). Its scope is to support and maintain the claimed Calibration and Measurement Capability (CMC) by the participants, which regularly offer the service of gauge block calibration by optical interferometry. The comparison was held from first half of 2018 to second half of 2019, and involved the measurement of eleven steel gauge blocks-eight in the range of short gauge block…