The invention relates to a mobile X-ray unit (10) comprising a base (2) for accommodating a control unit, a power supply and a cooler and further comprising an articulated displaceable arm (4a) supporting an X-ray applicator (4) provided with an X-ray tube, said X-ray applicator being connected to the base, the X-ray tube comprising a target for generating an X-ray beam and a collimator for shaping the generated X-ray beam. The X-ray applicator comprises an applicator cap for covering at least said surface.
