CCPR Key Comparisons

In support of Mutual Recognition Arrangement (MRA) signed in 1999, a series of international comparisons (Key Comparisons) are conducted on fundamental opical radiation quantities, organized by the Consultative Committee of Radiometry and Photometry (CCPR) under the auspices of the International Committee of Weights and Measures (CIPM). Currently, the following intercomparisons are completed or in progress.

• CCPR K1.a Spectral irradiance (250 nm to 2500 nm) 2001-2005 - complete
• CCPR K1.b Spectral irradiance (200 - 350 nm) - in progress
• CCPR K2.a Spectral responsivity (900 nm to 1600 nm) - in progress
• CCPR K2.b Spectral responsivity (300 nm to 1000 nm) 2000-2002 - complete
• CCPR K2.c Spectral responsivity (200 nm to 400 nm) - in progress
• CCPR K3.a Luminous intensity 1997-1998 - complete
• CCPR K3.b Luminous responsivity 1997 - complete
• CCPR K4 Luminous flux 1997-1998 - complete
• CCPR K5 Spectral diffuse reflectance - in progress
• CCPR K6 Spectral regular transmittance - in pogress

Also, there are three supplementary comparisons under CCPR on spectral radiance, cryogenic radiometer, and aperture area.

The details of the MRA, Key Comparisons, and CIPM/CCPR activities are available at BIPM website.

Results of the Key Comparisons on photometric units

The results of the CCPR K3a (luminous intensity), CCPR K3.b (luminous responsivity), and CCPR K4 (lluminous flux) are summrized below. Uncertaintiy bars are values with coverage factor k=2 reported by each participant. For official reference, refer to the published reports available at the photometry and radiometry section of Key Comparison Data Base.