The invention relates to a device (1) for generating X-rays (57). The device comprises a source (7) for emitting electrons (53) and a liquid metal for emitting X-rays as a result of the incidence of electrons. The device further comprises a displacing member (11) for displacing the liquid metal through an impingement position (55) where the electrons emitted by the source impinge upon the liquid metal. As a result of the flow of liquid metal through the impingement position the heat, which is generated in the impingement position as a result of the incidence of the electrons upon the liquid metal, is transported away from the impingement position.According to the invention, the displacing member (11) has a contact surface (61), which is in contact with the liquid metal in the impingement position (55), and a driving member (31) for moving the contact surface in a direction which, in the impingement position, is substantially parallel to the contact surface. Thus the flow of liquid metal in the impingement position is achieved as a result of viscous shear forces in the liquid metal caused by friction forces between the liquid metal and the moving contact surface. As a result, the necessary pressure of the liquid metal is limited.