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As the correction for atmospheric absorption is so significant, and it was not clear if the accuracy of the LOWTRAN calculations was sufficient for metrology purposes, experiments were conducted to confirm its predictions. Ideally one would compare the total detected flux a distance from a blackbody source through normal atmospheric and inert atmospheres. However, two difficulties with purging the total path were anticipated: firstly, the heavy oxide coating on the Inconel heatpipe is not stable in a neutral atmosphere, and secondly, the thermopile sensitivity may be slightly different under different atmospheres. We arranged to be able replace a part of 830 mm atmospheric path by a dry nitrogen atmosphere, leaving the heatpipe and thermopile in air. A 450 mm purge tube between the blackbody and thermopile with 15 mm apertures at either end could be flushed with dry nitrogen, whilst at either end small fans were used to ensure nitrogen escaping through the apertures was blown out of the optical path. Automatic cycling with a 5 minute period between dry N 2 and air in to tube modulated the detected thermopile signal allowing a clear measure of the absorption. Figure 3 shows a comparison of the measured and calculated absorption. The error band on the calculated data is due to uncertainties in the knowledge of the length of the effective air path, due to the hot air region in the heatpipe mouth and the ends of the purged tube (10 mm at each end). The measured and computed values agree within the measurement uncertainties. Uncertainty analysis The dominant uncertainty sources are the blackbody temperature measurement and uniformity, the temperature rise of the aperture plane and the uncertainty in effective atmospheric path length. Diffraction corrections are negligible, 0.04% at 20 µm (assuming a 20 mm aperture 200 mm from a 50 mm blackbody). Together these give a 2σ uncertainty of 0.3% over 500-1700 o C. Experiments using aperture-thermopile spacings of 300-600 mm, and with 10, 15 and 20 mm apertures give results agreeing well within these bounds. Conclusions A new facility for characterizing the response of heat-flux sensors to blackbody irradiance at a range of source temperatures has been established, with uncertainties as low as 0.3%. The new facility will be used to examine IR spectral sensitivity effects in heat-flux sensors. Acknowledgments The author would like to acknowledge Mr Chris Freund, who designed the experimental apparatus, and Mr Mark Darlow, who performed to precision machining and construction. References [1] Grosshandler, W.L., Heat Flux Transducer Calibration: Summary of the 2 nd Workshop, NISTIR 6424, NIST Washington, 1999 [2] CSIRO report RS22350, KB33/NML-1/13, 1992 [3] Ballico, M.J.,The CSIRO-NML Radiation thermometer Calibration Facility, in proc, Tempmeko 2004, Dubrovnik [4] M.Ballico, A simple technique for measuring the infrared emissivity of blackbody radiators, Metrologia, 2000, 37, 295-300 [5] M.Ballico,Modelling the effective emissivity of a graphite tube blackbody, Metrologia 1995/6,32, 259-265 Figure 1. Cross section and image of the water cooled low reflectance plate for stray IR control and holding the precision aperture and annular light trap. Transmission 100% 95% 90% 85% 80% 75% 2000 C 1500 C 800 C 500 C 0 0.5 1 1.5 2 2.5 3 (Path length /m )^0.5 Figure 2. Calculated integrated absorption as a function of distance for 50%RH at 21 o C and a range of source radiance temperatures. atmospheric absorption 4.00% 3.00% 2.00% 1.00% 0 C 1000 C 0.00% 400 600 800 1000 1200 1400 1600 1800 blackbody temperature deg.C measured LOTRAN Figure 3. Comparison of measured and calculated absorption between over 450 mm of a total 830 mm air path (50% RH, 21 o C) 274
A laser-based radiance source for calibration of radiation thermometers M. Ballico and P. B. Lukins National Measurement Institute of Australia, Lindfield Australia Abstract. An optical radiometric system based on a laser-diode-illuminated integrating sphere, a pair of calibrated apertures and calibrated silicon detectors is described. The radiance of the source has been determined to better than 0.04% (1σ), is stable in wavelength to
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NEWRAD PROCEEDINGS OF THE 9 TH INTE
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NEWRAD 2005 Scientific Program Day
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14:50 Hiroshi Shitomi, AIST 5-3 Pho
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NEWRAD 2005 Scientific Program-Post
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33. Drift in the absolute responsiv
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Session 6 Novel Techniques 64. The
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Session 9 Realisation of scales 94.
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Absolute Accuracy of Total Solar Ir
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Low-uncertainty absolute radiometri
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NIST Reference Cryogenic Radiometer
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Measurement of the absorptance of a
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Grooves for Emissivity and Absorpti
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New apparatus for the spectral radi
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VUV and Soft X-ray metrology statio
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The metrology line on the SOLEIL sy
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Cryogenic radiometer developments a
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measured with BiTe thermopiles. Exp
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variations of the spectral sensitiv
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aperture area by I = π·L·F·A, w
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Table 1 Ratio of radiometric power
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Consistency of radiometric temperat
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Project of absolute measuring instr
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Session 2 UV, Vis, and IR Radiometr
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Table 1: Summary of the quality ass
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wavelength / nm U180 @ MLS band wid
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ight half is uncoated. Measurements
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Change [%] 2 1 0 -1 -2 -3 -4 PTFE d
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had been accommodated to industrial
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Relative Uncertainty 0.4% 0.3% 0.2%
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instrument differences or from diff
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3.00E-08 Nomalized radiant flux 2.5
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frequencies, the chopping frequency
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600 mA for each set. In both cases,
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Detailed and comparative results wi
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measurement to an independent spect
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The stability of silicon n-on-p jun
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applied. Reproducibility of measure
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Mutual comparison Mutual comparison
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A comparison of the performance of
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Stray-light correction of array spe
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Characterizing the performance of U
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Optical Radiation Action Spectra fo
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A newly developed double broadband
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On potential discrepancies between
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Correcting for bandwidth effects in
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Establishment of Fiber Optic Measur
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Detector-based NIST-traceable Valid
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Long-term calibration of a New Zeal
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Drift in the absolute responsivitie
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Radiance source for CCD low-uncerta
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Improved NIR spectral responsivity
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Characterization of a portable, fib
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Synchrotron radiation based irradia
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The Spectral Irradiance and Radianc
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NIST BXR I Calibration A. Smith, T.
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NIST BXR II Infrared Transfer Radio
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Proceedings NEWRAD, 17-19 October 2
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Spectral responsivity interpolation
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Monochromator Based Calibration of
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Study of the Infrared Emissivity of
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Radiometric Stability of a Calibrat
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Session 3 Photolithography and UV P
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NEWRAD 2005: Improvements in EUV re
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Measuring pulse energy with solid s
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Vacuum ultraviolet quantum efficien
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Spatial Anisotropy of the Exciton R
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Comparison of spectral irradiance r
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Session 4 Remote sensing Proceeding
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Solar Radiometry from SORCE G. Kopp
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Inter-comparison Study of Terra and
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The Solar Bolometric Imager - Recen
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On measuring the radiant properties
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A Model of the Spectral Irradiance
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Determination of Aerosol Optical De
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Procedures of absolute calibration
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Using a Blackbody to Determine the
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On the drifts exhibited by cryogeni
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On-orbit Characterization of Terra
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Space solar patrol mission for moni
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Multi-channel ground-based and airb
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Thermal Modelling and Digital Servo
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Calibration of Filter Radiometers f
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Radiometric Calibration of a Coasta
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A Verification of the Ozone Monitor
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Session 5 Photometry and Colorimetr
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Review on new developments in Photo
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Linking Fluorescence Measurements t
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Photoluminescence from White Refere
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A Simple Stray-light Correction Mat
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New robot-based gonioreflectometer
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Rotational radiance invariance of d
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Minimizing Uncertainty for Traceabl
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Development of a total luminous flu
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Determination of the diffuser refer
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DEVELOPMENT OF A LUMINANCE STANDARD
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Measuring photon quantities in the
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Session 6 Novel techniques Proceedi
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Characterization of germanium photo
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Determination of luminous intensity
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The Measurement of Surface and Volu
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The evaluation of a pyroelectric de
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UV detector calibration based on an
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NEWRAD 2005: Non selective thermal
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Page 225 and 226: Simplified diffraction effects for
Page 227 and 228: Widely Tunable Twin-Beam Light Sour
Page 229 and 230: Measurement of quantum efficiency u
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Page 235 and 236: Comparison of Measurements of Spect
Page 237 and 238: APMP PR-S1 comparison on irradiance
Page 239 and 240: Comparison Measurements of Spectral
Page 241 and 242: Comparison of mid-infrared absorpta
Page 243 and 244: Comparison of photometer calibratio
Page 245 and 246: A Comparison of Re-C, Pt-C, and Co-
Page 247 and 248: Session 8 Radiometric and Photometr
Page 249 and 250: Application of Metal (Carbide)-Carb
Page 251 and 252: On Estimation of Distribution Tempe
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Page 255 and 256: Reproducible Metal-Carbon Eutectic
Page 257 and 258: Thermodynamic temperature determina
Page 259 and 260: Spatial Light Modulator-based Advan
Page 261 and 262: Novel subtractive band-pass filters
Page 263 and 264: Analysis of the Uncertainty Propaga
Page 265 and 266: Absolute linearity measurements on
Page 267 and 268: Comparison of two methods for spect
Page 269 and 270: Precision Extended-Area Low Tempera
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Page 273: A normal broadband irradiance (Heat
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Page 281 and 282: Determining the temperature of a bl
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Page 287 and 288: High-temperature fixed-point radiat
Page 289 and 290: A comparison of Co-C, Pd-C, Pt-C, R
Page 291 and 292: Irradiance measurements of Re-C, Ti
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Page 295 and 296: The Spectrally Tunable LED light So
Page 297 and 298: Session 9 Realisation of scales Pro
Page 299 and 300: The Realization and the Disseminati
Page 301 and 302: The establishment of the NPL infrar
Page 303 and 304: The PTB High-Accuracy Spectral Resp
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Page 307 and 308: An integrated sphere radiometer as
Page 309 and 310: From X-rays to T-rays: Synchrotron
Page 311 and 312: Infrared Radiometry at LNE: charact
Page 313 and 314: Transfer standard pyrometers for ra
Page 315 and 316: Preliminary Realization of a Spectr
Page 317 and 318: New photometric standards developme
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Detailed Comparison of Illuminance
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Radiometric Temperature Comparisons
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Characterization of Thermopile for
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Detector Based Traceability Chain E
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Comparison of the PTB Radiometric S
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Spectral Responsivity Scale between
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Realization of the NIST Total Spect
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Goniometric Realisation of Reflecta
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