: Bäumer, S.M.; Duparre, A.; Herrmann, T.; Schumann, U.; Smorenburg, K.; Kirschner, V.; Mattsson, L.H.; Quinteros, T.; Berglind, R.; Schippel, S.

Abstract
Light scattering measurements are important tools for characterizing optical surfaces can basically be divided into two main groups: total scatter measurements (TS) and Angle Resolved Scattering (ARS). Since TS measurements are fairly straight forward and widely used, international standardization has formulated an international draft standard on it, ISO/DIS 13696. ARS is a more complex method and not as common as TS measurements. However ARS data in form of the Bi-directional Reflectance Distribution FUnction (BRDF) can be used to predict stray light in Laser and Industrial Optical Systems. Because of increasing importance of this topic the EC is sponsoring a project regarding 'Standard procedures for stray light specification, measurement and testing - SLIOS'. During the project two of the activities are: performing a round robin experiment of measuring BRDF data at 5 different sites including some complementary techniques; compiling of an open access data base of measuredBRDF data, measured according to procedures agreed upon between the SLIOS partners and proposed for 'Standard Procedures'. Results of these two activities will be presented.