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Title: Sensitivity of blackbody effective emissivity to wavelength and temperature: By genetic algorithm

A variable-temperature blackbody (VTBB) is used to calibrate an infrared radiation thermometer (pyrometer). The effective emissivity (ε{sub eff}) of a VTBB is dependent on temperature and wavelength other than the geometry of the VTBB. In the calibration process the effective emissivity is often assumed to be constant within the wavelength and temperature range. There are practical situations where the sensitivity of the effective emissivity needs to be known and correction has to be applied. We present a method using a genetic algorithm to investigate the sensitivity of the effective emissivity to wavelength and temperature variation. Two matlab® programs are generated: the first to model the radiance temperature calculation and the second to connect the model to the genetic algorithm optimization toolbox. The effective emissivity parameter is taken as a chromosome and optimized at each wavelength and temperature point. The difference between the contact temperature (reading from a platinum resistance thermometer or liquid in glass thermometer) and radiance temperature (calculated from the ε{sub eff} values) is used as an objective function where merit values are calculated and best fit ε{sub eff} values selected. The best fit ε{sub eff} values obtained as a solution show how sensitive they are to temperature andmore » wavelength parameter variation. Uncertainty components that arise from wavelength and temperature variation are determined based on the sensitivity analysis. Numerical examples are considered for illustration.« less
Authors:
;  [1]
  1. National Metrology Institute of South Africa (NMISA), Private Bag X34, Lynnwood Ridge, Pretoria, 0040 (South Africa)
Publication Date:
OSTI Identifier:
22218042
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1552; Journal Issue: 1; Conference: 9. international temperature symposium, Los Angeles, CA (United States), 19-23 Mar 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ALGORITHMS; BLACKBODY RADIATION; CALIBRATION; CORRECTIONS; EMISSIVITY; GLASS; INFRARED RADIATION; LIQUIDS; MATHEMATICAL SOLUTIONS; PLATINUM; PYROMETERS; SENSITIVITY ANALYSIS; TEMPERATURE DEPENDENCE; TEMPERATURE MEASUREMENT; THERMOMETERS; VARIATIONS; WAVELENGTHS