A Method of Realizing Spectral Irradiance Based on an Absolute Cryogenic Radiometer

Johnson, Bettye C.; Cromer, Christopher L.; Saunders, Robert D.; Eppeldauer, George P.; Fowler, J. W.; Sapritsky, Victor I.; Dezsi, G

doi:10.1088/0026-1394/30/4/017

Cited by 46 publications

(25 citation statements)

References 10 publications

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“…Recently Mielenz, et al determined the freezing point of gold using calibrated detectors to determine the absolute spectral radiance within a selected wavelength band and inferred the temperature by application of Planck's radiation law [42]. Using the ideas developed by Mielenz, et al NIST has designed a FR based system coupled with a variable temperature blackbody to maintain the units of spectral radiance and irradiance [43,44]. This realization is based upon concepts associated with the conservation of radiance in a nonabsorbing medium with a constant index of refraction [14,45].…”

Section: B) Spectral Radiometrymentioning

confidence: 99%

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A national measurement system for radiometry, photometry, and pyrometry based upon absolute detectors

Parr¹

1996

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Gaithersburg, MD USA 20899-0001 Advancements in the performance and ease of use of absolute photodetectors based upon electrical substitution principals offers the possibility of a simplified and more accurate way to transfer the fundamental radiometric, photometric, and pyrometric units from NIST to the U.S. technical establishment. The history of electrical substitution radiometers at NIST is briefly reviewed and the implementation of the latest generation absolute cryogenic radiometer is discussed. Procedures to maintain fundamental units based upon a detector approach are reviewed in a general way with references to the technical literature for detailed discussion. It is proposed that NIST customers consider adopting the suggestions made in this technical note to simplify and improve their optical radiation based calibrations.

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Section: B) Spectral Radiometrymentioning

confidence: 99%

“…For example, if the filter has significant infrared leakage and the detector is a silicon photodiode, significant errors can result due to the increasing output of thermal sources in the infrared. These issues have been discussed in the literature [42][43][44]. NIST expects temperature to be determined to within 0.…”

Section: Detectormentioning

confidence: 99%

A national measurement system for radiometry, photometry, and pyrometry based upon absolute detectors

Parr¹

1996

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“…This achievement provided the impetus at NIST to decouple the spectral radiance and irradiance scales from any particular temperature scale (e.g., IPTS-68 or ITS-90) that might predefine the metal freezing-point temperatures. Instead, blackbody temperatures began to be measured ab initio using FRs traceable to absolute detectors [ 52 – 54 ]. Other national laboratories, including the National Physical Laboratory (NPL) in the U.K., the Physikalisch-Technische Bundesantalt (PTB) in Germany, and the All-Russian Institute for Optophysical Measurements (VNIIOFI) in Russia have also pursued this area of research.…”

Section: Spectral Sources and Pyrometrymentioning

confidence: 99%

The candela and photometric and radiometric measurements

Parr¹

2001

J. Res. Natl. Inst. Stand. Technol.

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The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.

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“…In principle, the HTBB could be calibrated with an independent (and dedicated) ACR, but NIST has adopted the approach of using the High Accuracy Cryogenic Radiometer (HACR) [ 150 ] as a central device and silicon photodiode trap detectors or other detectors to disseminate the spectral flux responsivity scale. The candela (SI base unit for luminous intensity) and detector spectral flux responsivity are realized this way [ 130 ], and it is the goal of the radiation temperature research to do the same for the radiance temperature, spectral radiance, and spectral irradiance scales [ 151 – 153 ].…”

Section: Part II Non-contact (Radiation) Thermometrymentioning

confidence: 99%

The Kelvin and temperature measurements

Bw¹,

Gt²,

Kg³

et al. 2001

J. Res. Natl. Inst. Stand. Technol.

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The International Temperature Scale of 1990 (ITS-90) is defined from 0.65 K upwards to the highest temperature measurable by spectral radiation thermometry, the radiation thermometry being based on the Planck radiation law. When it was developed, the ITS-90 represented thermodynamic temperatures as closely as possible. Part I of this paper describes the realization of contact thermometry up to 1234.93 K, the temperature range in which the ITS-90 is defined in terms of calibration of thermometers at 15 fixed points and vapor pressure/temperature relations which are phase equilibrium states of pure substances. The realization is accomplished by using fixed-point devices, containing samples of the highest available purity, and suitable temperature-controlled environments. All components are constructed to achieve the defining equilibrium states of the samples for the calibration of thermometers. The high quality of the temperature realization and measurements is well documented. Various research efforts are described, including research to improve the uncertainty in thermodynamic temperatures by measuring the velocity of sound in gas up to 800 K, research in applying noise thermometry techniques, and research on thermocouples. Thermometer calibration services and high-purity samples and devices suitable for “on-site” thermometer calibration that are available to the thermometry community are described. Part II of the paper describes the realization of temperature above 1234.93 K for which the ITS-90 is defined in terms of the calibration of spectroradiometers using reference blackbody sources that are at the temperature of the equilibrium liquid-solid phase transition of pure silver, gold, or copper. The realization of temperature from absolute spectral or total radiometry over the temperature range from about 60 K to 3000 K is also described. The dissemination of the temperature scale using radiation thermometry from NIST to the customer is achieved by calibration of blackbody sources, tungsten-strip lamps, and pyrometers. As an example of the research efforts in absolute radiometry, which impacts the NIST spectral irradiance and radiance scales, results with filter radiometers and a high-temperature blackbody are summarized.

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A Method of Realizing Spectral Irradiance Based on an Absolute Cryogenic Radiometer

Cited by 46 publications

References 10 publications

A national measurement system for radiometry, photometry, and pyrometry based upon absolute detectors

A national measurement system for radiometry, photometry, and pyrometry based upon absolute detectors

The candela and photometric and radiometric measurements

The Kelvin and temperature measurements

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