Intercomparison of the LBIR Absolute Cryogenic Radiometers to the NIST Optical Power Measurement Standard

Published

August 1, 2006

Author(s)

Adriaan C. Carter, James A. Fedchak, Raju V. Datla

Abstract

The Low Background Infrared (LBIR) facility at the National Institute of Standards and Technology (NIST) presently maintains four absolute cryogenic radiometers (ACRs) which serve as standard reference detectors for infrared calibrations performed by the facility. The primary standard for optical power measurements at NIST was the high accuracy cryogenic radiometer (HACR). Recently, an improved radiometer, the primary optical watt radiometer (POWR), has replaced the HACR as the primary standard. In this paper, we present the results of comparisons between the radiometric powers measured by the four ACRs maintained by the LBIR facility to that measured by the HACR and POWR. This is done by using a Si photodiode light-trapping detector as a secondary transfer standard to compare the primary national standards to the ACRs maintained by the LBIR facility. The technique used to compare an ACR to the trap detector is described in detail. The accuracy of the absolute optical power measurements is found to be within 0.1% of the primary standard for all the ACRs examined in this study.

Citation

Journal of Research (NIST JRES) -

Volume

111 No. 4

NIST Pub Series

Journal of Research (NIST JRES)

Pub Type

NIST Pubs

Keywords

absolute cryogenic radiometer, ACR, calibration, electrical substitution radiometers, HACR, high accuracy cryogenic radiometer, intercomparison, LBIR, optical power measurement standard

Citation

Carter, A. , Fedchak, J. and Datla, R. (2006), Intercomparison of the LBIR Absolute Cryogenic Radiometers to the NIST Optical Power Measurement Standard, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD (Accessed October 11, 2025)