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Photometry & Radiometry- Calibration ServicesOrdering Calibrations Services The Photometry and Radiometry Group develops and maintains the SI base unit of luminous intensity (the candela) and basic standards and measurement facilities in the fields of radiometry, photometry, and colorimetry, covering the spectrum from 200 nm in the ultraviolet to the far infrared. It disseminates these standards through calibration and consultation services to a varied clientele, which includes industries, universities, and government departments involved with lighting, transportation, public health and safety, communication, manufacturing, pulp and paper, television, and the environment. The Group maintains strong linkages with national and international standards laboratories and organizations through research, committee participation, and comparisons of national standards. ServicesUncertainties Facilities Fees for Service Contact: Dr. Joanne Zwinkels ServicesThe Photometry and Radiometry Group calibrates lamp standards of: luminous intensity, luminous flux, illuminance, luminance, spectral radiance and spectral irradiance for the wavelength range 300 nm to 800 nm. Spectrophotometric measurement services include spectral transmittances and spectral reflectances of transparent and opaque materials of all kinds (paints, plastics, textiles, ceramics, glass, etc.), including fluorescent materials. The spectral range covered depends upon the measurement, quantity; e.g. regular transmittance is avialable from 200 nm to 16 µm. Colour characterization of video displays is also offered as well as consultation services on the application of colour metrology to digital imaging. The Group can measure the characteristics of various types of detectors, such as silicon, germanium, and InGaAs photodiodes over the wavelength range 200 nm to 3000 nm. Detector properties that can be measured on a routine basis include: spectral responsivity, spectral temperature coefficients of responsivity, linearity, spatial and angular variation of uniformity of responsivity across a detector surface. Longwave (365 nm) and shortwave (254 nm) UV meters can also be calibrated. Gloss measurements at several standard geometries (20º, 60º, 45º, 85º) are made on specimens such as paints, papers, and ceramics. Primary calibrations of diffuse spectral reflectance factor can be performed on white standards for the pulp and paper industry. The colorimetric characteristics (chromaticity coordinates, colour differences) of paints, papers, textiles, plastics, etc. can be determined. The above list of measurement services is not comprehensive; other types of radiometric, photometric, colorimetric, and detector characterization measurements are available upon request. UncertaintiesUnless otherwise specified, the uncertainties quoted in the descriptions below are expanded uncertainties representing a confidence level of approximately 95%. They were obtained by multiplying the standard overall uncertainty (one standard deviation) by a coverage factor of k = 2. FacilitiesThe primary standard for realizing luminous intensity (candela) is an NRC-built electrically-calibrated thermal detector (absolute radiometer) equipped with V(λ)-correcting filters. Secondary standards of luminous intensity are in the form of carefully selected lamps traceable to the NRC absolute radiometers. The primary scales of spectral transmittance, reflectance, and gloss are based on specially built NRC reference instruments. Calibration facilities include: cryogenic and room-temperature absolute radiometers for first level spectral calibrations of transfer standard detectors; automatic spectroradiometers; lamp ageing facilities; photometric benches and an integrating sphere, an automated spectral responsivity measurement facility; automated detector characterization facities for linearity, spatial and angular variation of detector responsivity; a reference glossmeter; an absolute reflectometer for ISO 2469 calibrations of diffuse reflectance; a two-monochromator reference spectrofluorimeter, for calibrations of fluorescent reflecting materials; several automated spectrophotometers equipped with a variety of sampling accessories; an observation booth equipped with artificial daylight for visual assessments of colour differences between coloured materials; and a computer-controlled CRT-based visual colorimeter for research into improved colorimetry. Fees for ServiceOrdering Calibrations Services NEW procedures effective March 23, 2006.
Photometry of Incandescent Lamps Photometry of Incandescent LampsThe NRC scale of luminous intensity is based on the international 1979 CGPM definition of the candela using NRC absolute radiometers and is maintained on a group of specially selected Osram Wi41/G incandescent lamps. The standard uncertainty ( 1σ) of the primary luminous intensity scale is 0.5%. The NRC scale of luminous flux is based on measurements traceable to an NRC platinum blackbody source and is maintained on a set of 200 Watt and 500 Watt GEC incandescent lamps. The standard uncertainty ( 1σ) of the primary luminous flux scale is 1.5%. The following services describe routine photometric measurements that are available. Other specialized photometric tests may be performed upon special request. Lumen Standards - for use in sphere photometers(A33-06-01-01 to A33-06-01-02) These services cover the determination of the luminous flux (lumens) from one or more incandescent lamps at one voltage or current per lamp, up to 1000 watts, as follows:
Luminous Intensity Standards - for use on a horizontal bar photometer(A33-06-01-03 to A33-06-01-05) The horizontal luminous intensity (candelas) of one or more incandescent lamps is determined in a fixed direction at one or more voltages or currents per lamp, as follows:
Aging of Incandescent Lamps(A33-06-01-06 to A33-06-01-08) To ensure that lamps are stable enough to be used as standards, they should be operated or aged for a number of hours. These services cover the aging of lamps in a controlled environment, as follows:
Colour Temperature of Incandescent Lamps(A33-06-02-01 toA33-06-02-03) The colour temperature or the voltage for a specified colour temperature on one or more incandescent lamps can be determined within the range 2000 kelvin to 2856 kelvin, as follows:
Calibration of Photometric Instruments & SourcesIlluminance meters and luminance meters are calibrated photometrically on a custom basis using NRC luminous intensity standards. Special luminance tests are also available for displays, sphere sources and other luminance sources. Contact Dr. Arnold Gaertner for details.
Spectophotometry & ColorimetrySpectral Diffuse Transmittance and Reflectance Factors(A33-06-03-01 to A33-06-03-05B) Diffuse reflectance and transmittance measurements are available over the wavelength range 200 nm to 2200 nm and 5000 cm-1 to 600 cm-1. The NRC diffuse reflectance factor scale is based on the NRC Absolute Reflectometer, over the wavelength range 360 nm to 850 nm, with an uncertainty of 0.3%; at other wavelengths, it is based on the NIST scale, adjusted for the results of an NRC-NIST intercomparison in 1981. The overall uncertainty of routine calibrations of spectral diffuse transmittance or reflectance factors in the ultaviolet-visible-near infrared region, including or excluding the regular component, ranges from 0.4% to 0.7%, depending on the wavelength range, and excluding sample-dependent effects. The following services (A33-06-03-01 to A33-06-03-05) are for non-fluorescent materials and for standard wavelength ranges. Additional charges may apply for fluorescent materials or for non-standard measurement conditions. Total and diffuse reflectance measurements in the infrared (services A33-06-03-05A and A33-06-03-05B) are performed on an FTIR reflectometer incorporating an integrating sphere. The overall uncertainties in these values are (0.05R+0.04) where R is the measured total or diffuse reflectance value.
Spectral Regular Transmittance Factors(A33-06-03-06 to A33-06-03-10E) Calibrations of regular transmittance are traceable to the NRC Reference Spectrophotometer, which has an uncertainty of 2.5 parts in 104 in the visible range and 4.0 parts in 104 in the near-infrared range. Routine calibrations are performed on high-precision research spectrophotometers over the wavelength range 190 nm to 3200 nm; with a best measurement capability (relative) of 0.2%. Services are for calibrations using monochromatic irradiation. Arrangements can be made for special setups and supplementary measurements. Additional charges may apply for non-standard measurements, such as polarizing, highly spectrally selective, high transmission density, or small size samples. Spectral regular transmittance factors are measured for specified wavelength ranges, for one or more samples, as follows:
Absolute Specular Reflectance - 7.5° incidence(A33-06-03-11A to A33-06-03-12) The following services measure the absolute specular reflectance (7.5o incidence) for one or more samples for specified wavelength ranges and for a minimum and maximum sample size of 35 mm diameter and 50 mm diameter, respectively, and for a nominal reflectance exceeding 10%. Arrangements can be made to calibrate samples of smaller size or lower reflectance, but additional charges may apply.
Calculation of Colorimetric Quantities(A33-06-03-13 to A33-06-03-14A) In the following services, various colorimetric quantities are calculated from the spectrophotometric data. Calculations of other quantities (e.g. solar transmittance and reflectance) are available upon special request.
Calibration of White Reflectance Standards According to ISO 2469 and ISO 2470 StandardsThe following services provide for the calibration of white reflectance standards for the pulp and paper industry, according to ISO 2469 and ISO 2470 specifications.
Spectral radiance factors, 45°/0°GeometryThe NRC scale of absolute 45/0 spectral radiance factors is traceable to a master NRC pressed tablet of polytetrafluoroethylene calibrated for 45/0 geometry by NIST. The uncertainty of these NRC calibrations is ±0.7%.
Calibrated Stainless Steel Reflectance StandardNRC calibrates and issues a stainless steel reflectance standard for use in calibrating the specular reflectance scale of spectrophotometers.
Absolute Specular Reflectance at 10° to 80° incidence (s- and p-polarised)
SpectroradiometryThe NRC scale of spectral irradiance from 300 nm to 800 nm is based on the world-mean scale resulting from a 1973 international intercomparison of spectral irradiance scales, and is maintained on a group of 500 Watt quartz-halogen lamps. Calibrated spectral irradiance standard lamps can be purchased. These standards are 200 Watt quartz-halogen lamps, specially selected, aged and calibrated at a fixed dc current and with the spectral irradiance defined at a working distance of 43 cm. The standard uncertainty ( 1σ) in these lamp standards varies from 2% (400 nm to 800 nm), to 3% (350 nm to 400 nm), to 10% (300 nm to 350 nm). Spectral irradiance and spectral radiance calibrations are also available on user-supplied lamps over the same wavelength range. The spectral radiance calibrations are derived from NRC spectral irradiance standards or NIST spectral radiance standards. Spectral Irradiance (incandescent lamp)(A33-06-04-01 to A33-06-04-04) The following services cover measurements in specified wavelength ranges of the spectral irradiance from an incandescent lamp at a fixed distance and in a given direction.
Spectral Radiance (of a uniform incandescent lamp)These services measure the spectral radiance of a uniform incandescent lamp, in a given direction, for specified wavelength ranges and intervals.
Spectral Radiance (of a strip-filament lamp)The spectral radiance of a portion of a strip-filament lamp can be measured, in a given direction, for specified wavelength ranges and intervals.
Total Spectral Radiance Factors, Two Monochromator Method (45°/ 0°)The measurement facilities in spectrophotometry include a two-monochromator reference spectrofluorimeter for absolute radiometric calibrations of fluorescent reflecting materials. This instrument conforms to CIE and ASTM colorimetry standards and employs a measurement geometry of 45º annular illumination and 0º viewing, and an operating range of 250 nm to 1050 nm. The overall uncertainty of calibrations of total and reflected radiance factors of fluorescent standards is 1% (excluding sample-dependent effects).
Measurement of Detectors, Radiometers & PhotometersSpectral responsivity calibrations are traceable to NRC absolute radiometers. Measurements are performed using continuous (i.e. not chopped) radiation. The overall expanded uncertainty ( k=2 ) of routine calibrations ranges from 0.25% to 5%, depending upon the wavelength range and the type of detector, and excluding detector-specific effects. For absolute calibrations, a minimum detector size of 2.0 mm is normally required, but smaller detectors can sometimes be calibrated. Special set-up charges apply to photomultipliers. High-accuracy calibrations of specially-selected silicon and germanium photodiodes are also available upon special request. The minimum detector size for these calibrations is 5 mm. The combined standard uncertainty ( 1σ) for these measurements is about 0.3% for silicon (400 nm to 1000 nm) and 0.35% for germanium (1000 nm to 1600 nm). Other detector characterization measurements are available: temperature coefficients of responsivity; linearity (dynamic range of approximately 6 decades); spatial uniformity of responsivity; angular variation of responsivity ( underfill mode ); and calibration of shortwave and longwave UV meters. The following services are for one receiver of a given model.
Gloss MeasurementsSpecular gloss calibrations are performed on the NRC Reference Glossmeter using a specially-developed NRC quartz wedge as the primary standard. This measurement service is available for 20°, 60°, and 85° geometries according to ASTM D523 and ISO 2813 specifications, with an uncertainty of 0.3 gloss units, and at 45° geometry according to ISO 7668 specifications. The following fees are for non-metallic specimens. Additional charges apply for mirror samples.
Colorimetry of Video DisplaysColour characterization of customer's video displays (CRT, FPD, etc.) is available upon special arrangement. The reference spectroradiometer used at NRC for these measurements is traceable to NRC primary photometric standards. The following services are available:
In addition, calibration and verification services are available for colorimeters used for the routine measurement and adjustment of video displays of given types. This involves determining the relationship between the colorimeter's built-in colour matching functions and the CIE colour-matching functions.
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