Pulse modulated high-pressure caesium discharge lamp

The high-pressure caesium discharge has a favourable spectral distribution consisting of a smooth recombination continuum in the visible range. When o perated on a continuous power source, the spectrum in the visible region is close to blackbody radiation; however, the lamp efficacy is restrained by the self-reversed resonance lines occurring at 825 nm and 894 nm. Pulse mod ulation significantly increases the core plasma temperature, suppresses the near-infrared segment of the spectrum, strongly enhances the continuous ra diation in the visible region, and successfully avoids overloading (<40 W c m(-2)) the are tubes. The spectrum in the visible appears to have the same shape as blackbody radiation when the lamp is operated on a multiple pulse modulated power source. The arc tube geometry, caesium/mercury compositions, and power supply wavef orms were optimized for photometric performance through a series of compari son tests. The lamp efficacy increased with narrower diameter are tubes, hi gher lamp currents, as well as higher current crest factors (ratio of curre nt pulse peak to RMS current). The highest efficacy achieved for the lamp o perated on the pulse modulated power supply was 46 1pw. The lamp exhibits: excellent dimming characteristics and has a colour rendering index (CRI) ve ry close to a thermal source such as a tungsten halogen lamp. This study provides a framework for the design of a new lamp/ballast system which features excellent dimming characteristics, a near-perfect CRI, an e fficacy above 40 1pw, and long life. The application for this light source could be a replacement for a high-end tungsten halogen or a white high-pres sure sodium lamp.