Illuminance scale development from 1 klx to 200 klx

A calibration facility and associated measurement procedures have been established at the National Institute of Metrology (NIM, CHINA) to provide high illuminance calibrations in the range from 1 klx to 200 klx. An adjustable high illuminance source based on flux addition of LEDs in an integrating sphere has been developed, and the characteristics of the high illuminance source have been tested and analyzed. A correction method for the issues caused by the inherent structure of the light source has been proposed. A photometer was calibrated using the superposition method in the range (1-200) klx with a relative uncertainty from 0.5% to 1.0% varying with range (coverage factor k = 2).