Comparison of visible and infrared spectrum of light sources

We compared the visible and the infrared spectrum of cesium and the sodium high pressure discharge light sources of 70 W power, run at different voltages from 180 to 240 V. Although the cesium discharge lamp exhibits remarkable white light in the visible spectrum, it suffers from the large infrared radiation intensity. The study of the causes of large infrared losses and their possible reduction was the main motivation for the present investigation. Sodium discharge plasma appears to be more efficient light source than the cesium discharge plasma due to the smaller infrared emission, although the latter has much better colour rendering index.