A spectrometer (100) for characterizing a radiation beam, the spectrometer (100) comprising an optical radiation guiding system comprising a collimator (110) for collimating the radiation beam into a collimated radiation beam, and a beam shaper (120) for distributing the power of the collimated radiation beam over a discrete number of line shaped fields, and a spectrometer chip (130) wherein the spectrometer chip (130) is adapted for processing the radiation in a discrete number of line shaped fields coming from the beam shaper (120).