Stray light monitoring system with carousel for cylindrical or angular sample holders and beam stop for unscattered light which is enlarged such as to receive unscattered light refracted by the sample holder

摘要

The invention relates to a scattered light measuring system with at least one light source (20) for generating a beam (34), a receiving device for a measuring cell (17) or a plurality of measuring cells and a photodetector for receiving in particular scattered light from the measuring cell (nephelometry). According to the invention, it is provided that the measuring cell (17) and the radiation beam (34) are movable relative to one another in such a way that the radiation beam (34) travels through the measuring cell on a certain path section (37). Behind the measuring cell (17) collecting optics (29) is arranged, which throws the beam (34), which should not be measured on a preferably strip-shaped central aperture (24), so that it is not registered by the photodetector. However, the scattered light to be measured from the measuring cell (17) passes with its main portion past the central diaphragm (24) and can therefore be measured by the photodetector. The central diaphragm (24) therefore advantageously makes it possible for the radiation beam (34) and the measuring cell (17) to move relative to one another during the measurement. As a result, the efficiency of the measuring method, which is also provided under protection, advantageously increased.