Abstract: A cathode HAS a cathode head in which a surface emitter is arranged that emits electrons upon application of a heating voltage. The surface emitter is fashioned as a parallel surface emitter with at least two emitter surfaces spaced apart from one another, to which at least one electrically conductive cutoff electrode is fed that is galvanically separated from the parallel surface emitter. Such a cathode has a good cutoff capability.

Abstract: An x-ray tube has a number of emitters that generate respective electron beams, and has a common anode at which the electron beams strike on a surface to generate x-rays. A high x-ray dose power with a long lifespan are achieved while being able to quickly vary the x-ray dose power by using a superimposed intensity distribution from the x-ray beams, which is measured by a detector, to optimize the x-ray beams on the surface.

Abstract: An x-ray tube has a vacuum housing containing an anode that generates usable x-ray radiation upon being struck by electrons generated by an electron source. The usable x-ray radiation escapes from the vacuum housing through an x-ray exit window. A backscatter electron barrier device arranged in the vacuum housing affects the backscatter electrons in the region of the usable x-ray radiation such that no backscatter electrons reach the x-ray exit window. Such an x-ray tube exhibits an invariably constant x-ray intensity and a high reliability.

Abstract: An x-ray radiator for a medical technology x-ray apparatus, has a vacuum chamber arranged in a protective housing, in which is arranged an anode that emits an x-ray beam. The vacuum chamber is surrounded by a protective chamber formed between the protective housing and the vacuum chamber and filled with an electrically insulating liquid. A beam passage chamber filled with a gas is arranged in the protective chamber. The beam passage chamber is traversed by the x-ray beam exiting from the vacuum chamber and propagating toward the protective housing. The amount of secondary radiation generated by the x-ray radiator upon operation is thereby reduced.

Abstract: A method and a measurement system are disclosed for the noninvasive determination of properties of an object to be examined and to the use of a contrast medium for X-ray phase-contrast measurement. in at least one embodiment of the invention, a mixture (suspension) consisting of a base liquid and a multiplicity of particles contained therein is used, the refractive index of the base liquid being different to the refractive index of the particles.

Abstract: An X-ray optical transmission grating of a focus-detector arrangement of an X-ray apparatus is disclosed, for generating projective or tomographic phase contrast recordings of a subject. In at least one embodiment, the grating includes a multiplicity of grating bars and grating gaps arranged periodically on at least one surface of at least one wafer, wherein the X-ray optical transmission grating includes at least two sub-gratings arranged in direct succession in the beam direction.

Abstract: A focus-detector arrangement of an X-ray apparatus is disclosed for generating projective or tomographic phase contrast recordings with a phase grating. According to at least one embodiment of the invention, in the gaps between its bars, the phase grating includes a filler material whose linear attenuation coefficient in the relevant energy range is greater than that of the bars. The height of the filler material in the gaps is dimensioned on the one hand so that the X-radiation with the energy used for measuring the phase shift generates a phase shift in the X-radiation such that, after the phase grating, the rays which pass through the bars are phase shifted by one half wavelength relative to the rays which pass through the gaps with the filler material.

Abstract: An x-ray anode has an emission layer and a carrier with carrier material to support the emission layer. The carrier material is a metallized carbon fiber material with a portion in which the fibers are specifically directed. A high heat dissipation from the emission layer and a coefficient of heat expansion of the carrier that is advantageous for bonding with the emission layer are achieved.

Abstract: An x-ray radiator has an anode that emits x-rays, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, a voltage source for application of a high voltage between the anode and the cathode for acceleration of the emitted electrons toward the anode to form an electron beam, a vacuum housing, an insulator that is part of the vacuum housing and that separates the cathode from the anode, an arrangement for cooling components of the x-ray radiator, a deflection and arrangement that deflects the laser beam from a stationary source, that is arranged outside of the vacuum housing, to a spatially stationary laser focal spot on the cathode.

Abstract: An x-ray unit has an x-ray radiator having an anode that emits x-rays upon being struck by electrons, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, electrical connections for application of a high voltage between the anode and the cathode to accelerate the emitted electrons toward the anode as an electron beam, a vacuum housing that can be rotated around an axis, an insulator that is part of the vacuum housing and that separates the cathode from the anode, a drive that rotates the vacuum housing around its axis, an arrangement for cooling components of the x-ray radiator, and an arrangement that directs the laser beam from a stationary source, arranged outside of the vacuum housing, onto a spatially stationary laser focal spot on the cathode and that focuses the laser beam.

Abstract: A cathode has an emission layer that thermionically emits electrons upon exposure with a laser beam. The material of the emission layer has a product of density (?), measured in kg m 3 , heat capacity (Cp), measured in J kg ? ? K and heat conductivity (?), measured in W mK that is, at room temperature, maximally 500,000 J 2 m 4 ? K 2 ? s . Such a cathode has an improved thermionic emission of electrons.

Abstract: A focus-detector arrangement of an X-ray apparatus is disclosed, for generating projective or tomographic phase contrast recordings of a subject. In at least one embodiment, least one grating of a focus-detector arrangement includes, at least partially, a macroscopically homogeneous medium which, when excited by an energy source, assumes a periodic structure/standing wave field that leads to beam splitting and the formation of an interference pattern when the X-ray beam passes through.

Abstract: An x-ray apparatus has a cooling device for cooling of the anode, through which cooling device cooling fluid flows. To improve the cooling effect, the coolant is water and a pressure generation device is provided for generation of a water pressure of more than 1.1 bar acting at least in a region of the anode to be cooled.

Abstract: A method and a measuring arrangement are disclosed for nondestructive analysis of an examination object. In at least one embodiment of the method, x-radiation having a specific energy spectrum is generated by an x-ray source, with the aid of at least one x-ray/optical grating in the beam path of the x-radiation there is generated a standing wave field of this x-radiation that is positioned at least partially in the examination object, and the radiation excited by the x-ray standing wave field in the examination object is measured as a function of at least one relative position between the examination object and the x-ray standing wave field. Further, a material distribution in the examination object is inferred from the measurement result of the radiation excited by the x-ray standing wave field.

Abstract: A focus-detector arrangement of an X-ray apparatus is disclosed for generating projective or tomographic phase contrast recordings of an observed region of a subject. In at least one embodiment, the arrangement includes a radiation source which emits a coherent or quasi-coherent X-radiation and irradiates the subject, a phase grating which is arranged behind the subject in the beam path of the radiation source and generates an interference pattern of the X-radiation in a predetermined energy range, and an analysis-detector system which detects at least the interference pattern generated by the phase grating in respect of its phase shift with position resolution. Further, the beam path of the X-radiation used diverges in at least one plane between the focus and the detector.

Abstract: A rotating envelope tube has a housing which with an x-ray exit window that is essentially transparent for x-ray radiation. To improve the mechanical stability, the x-ray exit window internally exhibits a structure through which cooling fluid can flow.

Abstract: An x-ray radiator has a vacuum housing that can rotate around an axis, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, an anode that emits x-rays upon being struck by the electrons, an insulator that is part of the vacuum housing and that separates the cathode from the anode, electrodes or terminals to apply a high voltage between the anode and the cathode to accelerate the emitted electrons toward the anode to form an electron beam, a drive arrangement for rotation of the vacuum housing around its axis, an arrangement for cooling components of the x-ray radiator, and an arrangement that directs and focuses the laser beam from a stationary source that is arranged outside of the vacuum housing onto a spatially stationary laser focal spot on the cathode.

Abstract: A rotating envelope radiator has a radiator housing surrounded by an external housing to form an intervening space in which a coolant flows. To prevent the formation, at high rotational frequencies, of reverse flows of the coolant in the intervening space, a flow conductor structure is provided in the intervening space that counteracts the formation of tangential flow components in the coolant.

Abstract: An x-ray anode has an emission layer and a carrier with carrier material to support the emission layer. The carrier material is a metallized carbon fiber material with a portion in which the fibers are specifically directed. A high heat dissipation from the emission layer and a coefficient of heat expansion of the carrier that is advantageous for bonding with the emission layer are achieved.

Abstract: In a method for operating an x-ray device, an x-ray beam is generated at a focal spot of a rotary anode that is rotatable around a rotation axis, and the x-ray beam is gated with a slit-shaped diaphragm to produce a fan-shaped x-ray beam, that is moved through an examination region in the manner of a scan. To improve the image resolution, the fan-shaped x-ray beam can be moved over the examination region essentially in the direction of the rotational axis of the rotary anode by tilting the x-ray tube on the focal spot, with the x-ray tube being tilted on the focal spot so that the fan-shaped x-ray beam is always gated from the region of the overall emitted x-ray beam having the highest image resolution or the highest image definition in the movement through the examination region.