A lithographic apparatus includes a radiation system for providing a beam of radiation from radiation emitted by a radiation source. The radiation system includes a contaminant trap for trapping material emanating from the radiation source. The rotation contaminant trap includes a multiple number of elements extending in a radial direction from a common rotation trap axis and being arranged for allowing contaminant material emanating from the radiation source to deposit during propagation of the radiation beam in the radiation system. The radiation system further includes a contaminant catch for receiving contaminant material particles from the rotation trap elements, the contaminant catch having a constitution, during operation of the radiation, for retaining said contaminant material particles.