| 摘要 |
The invention relates to a device (1) for measuring the refractive index n of a medium (2, 2a, 2b), comprising: a white light interferometer (3), which has a light source (11), a beam splitter (14) for splitting the light (21) emitted by the light source (11) into a reference beam (22), and a detection beam (23), which detection beam can be guided through the medium (2, 2a, 2b), a reference path (13, 13a) having a variable length (L), on which reference path the reference beam (22) is guided, and a detector (15) for measuring the interference product (100) formed from the reference beam (22) and the detection beam (23); and an evaluating unit (101), which is designed to determine the refractive index n from the functional dependency of the interference product (100) on the length L. The invention further relates to a system (110) for measuring the concentration of urea (2a) in a solution (2) for the aftertreatment of exhaust gas in a motor vehicle (4), said solution containing at least urea (2a) and water (2b), comprising a device (1) according to the invention, wherein the detection beam (23) of the device (1) is guided through a storage tank (41) for the solution (2) and/or through a line (42) that conducts the solution. |
