The invention relates to a device for generating X-rays (18) comprising an electron source (3) for emitting electrons accommodated in a vacuum space (2), a liquid metal circuit including a liquid metal for emitting X-rays as a result of the incidence of electrons and a pumping means (11) for causing a flow of the liquid metal through a constriction (7) where the electrons emitted by the electron source (3) impinge upon the liquid metal, and a radiation window (12) bounding said constriction (7), which is transparent to electrons and X-rays and separates the constriction (7) from the vacuum space (2). To provide a device for generating X-rays in which a cross-sectional area of the constriction substantially corresponds to an intended, desired cross-sectional area due to a self-regulating process without the need for external or additional components or electronics, it is proposed that said constriction (7) being bounded by a compensation window (13) opposite of said radiation window (12), which separates the constriction (7) from a pressure chamber (14) containing liquid metal provided by said liquid metal circuit via a connection (15), and which, during operation, has a profile (p') as a result of a deformation caused by a pressure in the pressure chamber (14) different from the pressure in the constriction (7) which substantially matches a profile (p) which the radiation window (12) has, during operation, as a result of a deformation of the radiation window (12) caused by a pressure of the liquid metal in the constriction (7).