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.
, Yoon, H.
, Zong, Y.
, Larason, T.
, Smith, A.
and Racz, M.
Radiometer standard for absolute responsivity calibrations from 950 nm to 1650 nm with 0.05% (k = 2) uncertainty, Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=900973
(Accessed October 22, 2021)