Traceability of Total Spectral Radiant Flux (TSRF) Scale Using Spectral Irradiance and Total Luminous Flux Scale at CSIR-NPL, India

In the modern era of LED lighting, spectral radiant flux standards are in high demand from lighting manufacturers to testing laboratories. In the present article, the traceability of the total spectral radiant flux (TSRF) scale is established using the spectral irradiance scale and the total luminous flux scale at CSIR-NPL, India with an expanded uncertainty of 3.8% in the visible range of 410–780 nm. A low voltage commercially available quartz tungsten halogen (QTH) lamp is developed as standard and used for calibration of a sphere spectroradiometer system for the measurements of total luminous flux and correlated color temperature (CCT) of different types of light sources. It is found that the measured total luminous flux and CCTs of all the lamps under study are within ± 1.5% as compared to their respective reference values measured using standard protocol.