Realization of luminous flux scale using the integrating sphere

Luminous flux calibration facility with an integrating sphere has been established at the Metrology Institute of Turkey (UME) in order to realize lumen. A computer controlled electrical system named as Lab- View was developed to operate light sources and to control electrical parameters. In this work, the luminous fluxes of the lamps, measured by means of goniophotometric method in PTB, Germany, were measured by using classic integrating sphere method and the results were compared. Regarding to the corrections of the sphere system, inner coating reflectance, spatial non-uniformity, self absorption factor and interior temperature variations were characterized. The total uncertainty in luminous flux measurement was determined with an uncertainty of 1.14 % (k=2) in the range between 5 lm - 5000 lm. Keywords: Luminous flux, lumen, integrating sphere, luminance, characterization, uncertainty