Scanning-slit profilers use a narrow slit instead of a single knife edge. In this case, the intensity is integrated over the width of the slit. The resulting measurement is equivalent to the original cross section convolved with the profile of the slit. Scanning beam profilers are most suitable for beam profiles which are not too far from Gaussian, because the recorded signal is usually integrated in one spatial direction, so that the reconstruction of more structured beam shapes may not be perfect. The advantage of scanning slit beam profiling is sub-micron precision for measuring beam position and size. An important advantage of the concept of scanning is that the photodetector used does not need to have a great spatial resolution, so that detectors for very different wavelength regions can easily be used.