CALIBRATION OF SPECTRAL IRRADIANCE SOURCES USING A FIBER-COUPLED SYSTEM

2021 ◽  
Author(s):  
H.T.B Lee ◽  
Y.C. Chau ◽  
H.S.B. Lam
Keyword(s):  
Measurement Uncertainty ◽  
Light Source ◽  
Spectral Range ◽  
Coupled System ◽  
Measurement Model ◽  
Spectral Irradiance ◽  
Calibration Laboratory ◽  
Calibration Setup

The standards and Calibration Laboratory has recently developed the calibration service for the enclosed-type irradiance light source in the spectral range from 300 nm to 850 nm. The calibration is based on the source-based method measured by a fiber-coupled system. In this paper, the calibration setup, measurement model and the associated uncertainty are presented. The expanded measurement uncertainty is estimated to be less than 3,3 % over the measured spectral range which can support the needs from the testing and certification industry.

Estimation of uncertainty in olfactometry

2009 ◽  
Vol 59 (7) ◽  
pp. 1409-1413 ◽  
Author(s):  
T. Higuchi
Keyword(s):  
Measurement Uncertainty ◽  
Interlaboratory Comparison ◽  
Collaborative Study ◽  
Estimation Procedure ◽  
Measurement Model ◽  
Standard Uncertainty ◽  
Expanded Uncertainty ◽  
Collaborative Test ◽  
Measurement Results ◽  
Estimation Of Uncertainty

Estimation of uncertainty in odour measurement is essential to the interpretation of the measurement results. The fundamental procedure for the estimation of measurement uncertainty comprises the specification of the measurement process, expression of the measurement model and all influences, evaluation of the standard uncertainty of each component, calculation of the combined standard uncertainty, determination of a coverage factor, calculation of the expanded uncertainty and reporting. Collaborative study such as interlaboratory comparison of olfactometry yields performance indicators of the measurement method including repeatability and reproducibility. Therefore, the use of collaborative test results for measurement uncertainty estimation according to ISO/TS 21748 and ISO 20988 is effective and reasonable. Measurement uncertainty of the triangular odour bag method was estimated using interlaboratory comparison data from 2003 to 2007 on the basis of the simplest model of statistical analysis, and the expanded uncertainty of odour index ranged between 3.1 and 6.7. On the basis of the establishment of the estimation procedure for uncertainty, a coherent interpretation method for the measurement results will be proposed and more effective and practical quality control of olfactometry will be available.

Spectral Irradiance Distribution in Underwater Light Field Generated by an LED Light Source

2020 ◽  
Vol 103 (sp1) ◽  
pp. 453
Author(s):  
Ping Yang ◽  
Zizhao Wu ◽  
Yao Chen ◽  
Yilu Guo ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Light Source ◽  
Light Field ◽  
Spectral Irradiance ◽  
Led Light ◽  
Underwater Light Field ◽  
Underwater Light

High-resolution continuum-source electrothermal atomic absorption spectrometer for simultaneous multi-element determination in the spectral range of 190–780 nm

2019 ◽  
Vol 34 (5) ◽  
pp. 1005-1010 ◽  
Author(s):  
V. A. Labusov ◽  
S. S. Boldova ◽  
D. O. Selunin ◽  
Z. V. Semenov ◽  
P. V. Vashchenko ◽  
...  
Keyword(s):  
High Resolution ◽  
Atomic Absorption ◽  
Light Source ◽  
Spectral Range ◽  
Atomic Absorption Spectrometer ◽  
Electrothermal Atomizer ◽  
Element Determination ◽  
Continuum Source ◽  
Absorption Spectrometer

We have built a prototype atomic absorption spectrometer with an electrothermal atomizer and continuum light source for simultaneous multi-element determination.

scholarly journals Method of kurtosis in estimating the measurement uncertainty during calibration of the electrical resistance measures using a potentiometer

2021 ◽  
pp. 30-34
Author(s):  
Igor Zakharov ◽  
Olesia Botsiura ◽  
Valerii Semenikhin
Keyword(s):  
Measurement Uncertainty ◽  
Electrical Resistance ◽  
Voltage Drop ◽  
Measurement Model ◽  
Standard Uncertainty ◽  
The Monte Carlo Method ◽  
Resistance Measure ◽  
Distribution Laws ◽  
Single Size ◽  
Good Agreement

Calibration of electrical resistance measures is considered by the indirect method, which is realized through measuring the voltage drop across the series-connected reference and calibrated resistors. The biases of the estimates of the measurand and the combined standard uncertainty due to the nonlinearity of the measurement model were calculated. The distribution laws of the input quantities in the calculation of the expanded uncertainty were taken into account by the kurtosis method. An example of measurement uncertainty evaluating during calibration of single-size electrical resistance measure R331 with a nominal resistance of 1000 Ω by comparing its value using a potentiometer R345 with the value of the calibrated reference standard is considered. Estimates of the measurand and its standard and expanded uncertainties obtained using the proposed method showed good agreement with the estimates obtained using the Monte Carlo method.

scholarly journals Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

2017 ◽  
Author(s):  
Ralf Zuber ◽  
Peter Sperfeld ◽  
Stefan Riechelmann ◽  
Saulius Nevas ◽  
Meelis Sildoja ◽  
...  
Keyword(s):  
Spectral Range ◽  
Solar Irradiance ◽  
Total Ozone ◽  
Spectral Irradiance ◽  
Stray Light ◽  
Limiting Factor ◽  
Total Ozone Column ◽  
Reduction Methods ◽  
Robust Measurements ◽  
Ozone Column

Abstract. A compact array spectroradiometer technology that enables precise and robust measurements of UV spectral irradiance is presented. The spectroradiometer design allows various applications such as measurement of high-power UV lamps, risk assessment of sources and measurement of solar irradiance. We show that this technology can perform precise total ozone column (TOC) retrieval. The internal stray light, which is often the limiting factor for measurements in the UV spectral range and increases the uncertainty for TOC analysis significantly, is physically reduced so that no other stray light 15 reduction methods, such as mathematical corrections, are necessary. The instrument and its elaborate components have been extensively characterised at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. During an international total ozone measurement intercomparison at the Izaña observatory in Tenerife, the high-quality applicability of the instrument was verified with measurements of the direct solar irradiance and subsequent TOC evaluations based on the spectral data between 12 and 30 September 2016. The results showed deviations of less than 1.5 % to most other instruments in most 20 situations not exceeding 3 % compared to established TOC measurement systems such as Dobson or Brewer.

scholarly journals AC/DC transfer standards calibration in Central Military Calibration Laboratory

2017 ◽  
Vol 66 (4) ◽  
pp. 217-228
Author(s):  
Przemysław Piróg ◽  
Mariusz Górecki
Keyword(s):  
Measurement Uncertainty ◽  
Metrological Traceability ◽  
Uncertainty Budget ◽  
Voltage Measurement ◽  
Measurement Equation ◽  
Calibration Laboratory ◽  
Transfer Standard ◽  
Thermal Voltage

The article discusses the method used in the Central Military Calibration Laboratory to calibrate Fluke 5790 AC/DC transfer standard with reference transfer standard Fluke 792A. It presents the measurement equation and the uncertainty budget. The contribution of uncertainty components in the measurement uncertainty has been presented. The metrological traceability has been evaluated by comparing calibration results with the results in the last Fluke certificate of calibration. Keywords: AC/DC converters, AC/DC difference, thermal voltage converters (TVCs), AC voltage measurement.

Performance of Nozzle, Venturi, and Orifice Meters Relative to Extrapolation Criteria

2008 ◽  
Author(s):  
James B. Nystrom ◽  
Phillip S. Stacy
Keyword(s):  
Reynolds Number ◽  
Measurement Uncertainty ◽  
Flow Measurement ◽  
Discharge Coefficient ◽  
Operating Conditions ◽  
Compressible Fluids ◽  
Calibration Data ◽  
Dimensionless Numbers ◽  
Flow Meter ◽  
Calibration Laboratory

Flow meter performance is described by the dimensionless numbers of discharge coefficient and Reynolds number. To achieve the best flow measurement uncertainty, meters are tested (calibrated) to determine the discharge coefficient behavior versus Reynolds number (magnitude and slope). Various meter designs have differing Reynolds number dependence. In many cases calibration laboratories can not achieve the Reynolds number at which the flow meter will operate. This deficiency is usually due to fluid properties (density and viscosity) at operating conditions being considerably different than those in a water-based calibration laboratory. Testing using fluids such as natural gas may increase the achievable Reynolds number but it is difficult to achieve the low uncertainty of the discharge coefficient possible in a water calibration due to the additional uncertainty of the expansion factor required with compressible fluids and the problems associated with gravimetric measurements of compressible fluids. In some power industry applications, operating Reynolds numbers may be an order of magnitude higher than can be achieved during calibration. Therefore, calibration data must be used to infer the discharge coefficient at operating conditions (Reynolds number), defining extrapolation. In Code tests, minimum flow measurement uncertainty is the objective and the uncertainty must be estimated. The largest uncertainty component in a flow measurement application usually is the discharge coefficient, which is dependent on the care of fabrication, the calibration data, and the extrapolation process. Measured discharge coefficients of Throat Tap Nozzles, Venturi meters Wall Tap Nozzles, and Orifice Meters are compared to predictive equations.

scholarly journals Results from Verification of Reference Irradiance and Radiance Sources Laboratory Calibration Experiment Campaign

2020 ◽  
Vol 12 (14) ◽  
pp. 2220
Author(s):  
Agnieszka Białek ◽  
Teresa Goodman ◽  
Emma Woolliams ◽  
Johannes F. S. Brachmann ◽  
Thomas Schwarzmaier ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Spectral Range ◽  
Effective Field ◽  
Field Of View ◽  
Spectral Irradiance ◽  
Spectral Bands ◽  
Calibration Experiment ◽  
Comparison Results ◽  
Laboratory Calibration ◽  
Filament Lamps

We present the results from Verification of Reference Irradiance and Radiance Sources Laboratory Calibration Experiment Campaign. Ten international laboratories took part in the measurements. The spectral irradiance comparison included the measurements of the 1000 W tungsten halogen filament lamps in the spectral range of 350 nm–900 nm in the pilot laboratory. The radiance comparison took a form of round robin where each participant in turn received two transfer radiometers and did the radiance calibration in their own laboratory. The transfer radiometers have seven spectral bands covering the wavelength range from 400 nm–700 nm. The irradiance comparison results showed an agreement between all lamps within ±1.5%. The radiance comparison results presented higher than expected discrepancies at the level of ±4%. Additional investigation to determine the causes for these discrepancies identified them as a combination of the size-of-source effect and instrument effective field of view that affected some of the results.

HANDLING OF CORRELATIONS OF SPECTRAL QUANTITIES IN TRACEABILITY CHAIN – BASICS FOR A PYTHON-BASED ANALYSIS FRAMEWORKE

2021 ◽  
Author(s):  
Philipp Schneider ◽  
Thorsten Gerloff ◽  
Armin Sperling
Keyword(s):  
Measurement Uncertainty ◽  
Test Methods ◽  
Correlated Data ◽  
Test Laboratory ◽  
Spectral Irradiance ◽  
Analysis Framework ◽  
Major Goal ◽  
Traceability Chain ◽  
Measurement Uncertainties

In this contribution a framework is presented that aims to help for handling correlations within measurement uncertainty calculations for spectral quantities. Taking correlations for spectral quantities into account is necessary as they directly influence the measurement uncertainties especially for integral quantities. Therefore, determination of correlations within traceability chains at national metrology institutes (NMIs) and disseminations of correlated data to test laboratory level is encouraged and a major goal of the EMPIR project 19NRM02 “Revision and extension of standards for test methods for LED lamps, luminaires and modules” (RevStdLED). The presented python-based analysis framework is used in photometry and spectroradiometry at PTB to calculate the results and associated measurement uncertainty for spectral irradiance, spectral irradiance responsivity and luminous responsivity based on spectral calibrations.

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