The Model 5000-16C 1000-watt FEL Lamp Standard provides absolute calibration of spectral irradiance from 250 nm to 2.5 microns. This tungsten-halogen lamp standard bears the ANSI designation of FEL. It has been selected by the National Institute of Standards and Technology to replace the 1000-watt, DXW standard. It is calibrated to the 1973 NIST spectral irradiance scale, while the DXW standard is calibrated to the 1965 NIST Scale.

Lamp calibration is directly traceable to the National Institute of Standards and Technology by incorporating two NIST spectral irradiance scales. This results in estimated accuracies of 2.4% at 250 nm, 1.8% at 450 nm and 1.5% over the range from 555 to 1600 nm. The 1965 NIST Scale of spectral irradiance is used over the spectral range from 1700- to 2500-nm. NIST uncertainty over this wavelength region is approximately 3%. There is no appreciable degradation of accuracy in the Gamma Scientific transfer calibration process.