Yoshihiro Ohno, Steven W. Brown, Thomas C. Larason
Under the framework of Mutual Recognition Arrangement (MRA) for national measurements standards and for calibration and measurement certificates issued by National Metrology Institutes (NMIs) signed in 1999, an international comparison of spectral responsivity in the near infrared region 900 nm to 1600 nm, designated CCPR K2.a, was conducted under Consultative Committee of Photometry and Radiometry (CCPR). This comparison was piloted by National Institute of Standards and Technology and participated by 15 laboratories. The comparison was conducted following the Guidelines for CIPM key comparisons (1999) and the data was analyzed following the Guidelines for CCPR comparison report preparation (2006). The results of most of the laboratories agreed within ±1 % difference in the entire spectral range except for a few outliers having the largest deviations up to 4 % from the Key Comparison Reference Values at some wavelengths. The unilateral and bilateral degrees of equivalence of all participating NMIs are provided.