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Radiometer standard for absolute responsivity calibrations from 950 nm to 1650 nm with 0.05% (k = 2) uncertainty



George P. Eppeldauer, Howard W. Yoon, Yuqin Zong, Thomas C. Larason, Allan W. Smith, M. Racz


A sphere-input transfer-standard detector has been developed to calibrate detectors and radiometers for absolute spectral power, irradiance, and radiance responsivity in the near-IR range with uncertainties similar to those of silicon trap-detector calibrations. The new near-IR reference detector is utilized at the SIRCUS which is the reference calibration facility of NIST for absolute responsivity. The transfer-standard sphere-detector converts the radiant-power scale of the primary-standard cryogenic-radiometer into an irradiance responsivity scale using a tilted input aperture and four symmetrically positioned InGaAs detectors around the sphere-axis and the incident beam-spot. The low conversion uncertainty is the result of a spatial non-uniformity of responsivity of less than 0.05 %. The deviation of the angular responsivity from the cosine function is about 0.03 % in a five-degree angular range. With the new reference detector, a thermodynamic temperature uncertainty of 10 mK (k=2) can be achieved at 157 oC of the In fixed point blackbody.


irradiance, near-infrared, radiant power, reference detector, spectral responsivity, transfer standard


Eppeldauer, G. , Yoon, H. , Zong, Y. , Larason, T. , Smith, A. and Racz, M. (2009), Radiometer standard for absolute responsivity calibrations from 950 nm to 1650 nm with 0.05% (k = 2) uncertainty, Metrologia, [online], (Accessed May 24, 2024)


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Created June 2, 2009, Updated February 19, 2017