Experimental Characterization and Statistical Modeling of Na-Sc Iodide Lamps

Abstract

The authors have conducted an empirical study of the properties of Na-Sc metal halide lamps over a wide range of compositions and operating conditions. They made lamps with additive compositions which formed grids covering two carefully controlled parameter spaces designed to include most compositions of practical interest. They also used a multivariate linear regression analysis to obtain data fits over regions of parameter space where diffuse, wall-stabilized arcs were obtained; data on constricted arcs were too erratic for this analysis. Their results characterize lamp properties for diffuse arcs and locate the regions in parameter space where constricted arcs are obtained. These results show a number of interdependences that were not previously obvious, and clarify available design trade-offs, as well as providing a diagnostic to insure meeting composition specifications.