Transforming the Sandia 2{line_integral} optical performance measurement system to color

A monochrome 2f optical performance measurement system at Sandia. To meet the goals of an optical test method that can be done in a relatively short period of time, requires little space, uses ``off the shelf`` test equipment, and provides a quantitative measure adequate to address quality control requirements, necessitates conversion of the system to use color. This test method is based on common ray trace calculations for targets and images at the radius of curvature for spherical and parabolic (f/D>3) concentrators. The implementation of a color system involved changing hardware and software. Target design -- the layout, materials, and color selection -- is a primary consideration. As the system development neared completion, it was used in several applications to measure solar concentrator facet performance and evaluate system performance. Included in this testing was a side-by-side test with the SHOT system at the National Renewable Energy Laboratory. This paper discusses the development of the color system hardware, reviews the results of testing, and presents the color system software.