Embodiments provide a stationary X-ray source for a multisource X-ray imaging system for tomographic imaging. The stationary X-ray source includes an array of thermionic cathodes and, in most embodiments a rotating anode. The anode rotates about a rotation axis, however the anode is stationary in the horizontal or vertical dimensions (e.g. about axes perpendicular to the rotation axis). The elimination of mechanical motion improves the image quality by elimination of mechanical vibration and source motion; simplifies system design that reduces system size and cost; increases angular coverage with no increase in scan time; and results in short scan times to, in medical some medical imaging applications, reduce patient-motion-induced blurring.

A collimator for an x-ray tube can be a monolithic, integral structure. The collimator can include a proximal-end closest to a cathode and a distal-end farthest from the cathode. The proximal-end can adjoin a vacuum inside of the x-ray tube. The distal-end can adjoin the air. The collimator can include an aperture extending therethrough. An x-ray window can be mounted across the aperture. The aperture can include a collimation-region between the x-ray window and the distal-end, and a drift-region between the x-ray window and the proximal-end. X-rays can be generated inside of the collimator.

A collimator for an x-ray tube can be a monolithic, integral structure. The collimator can include a proximal-end closest to a cathode and a distal-end farthest from the cathode. The proximal-end can adjoin a vacuum inside of the x-ray tube. The distal-end can adjoin the air. The collimator can include an aperture extending therethrough. An x-ray window can be mounted across the aperture. The aperture can include a collimation-region between the x-ray window and the distal-end, and a drift-region between the x-ray window and the proximal-end. X-rays can be generated inside of the collimator.

X-ray target element is comprised of a planar wafer. The planar wafer element includes a target layer and a substrate layer. The target layer is comprised of an element having a relatively high atomic number and the substrate layer is comprised of diamond. The substrate layer is configured to support the target layer and facilitate transfer of thermal energy away from the target layer.

An x-ray generating unit includes an x-ray tube that is substantially transparent to x-rays. A cathode is within the x-ray tube and defines a plurality of spaced apart cavities. An anode includes a material that emits x-rays when impacted by electrons. A plurality of filaments is each disposed in a different one of the cavities. Each of the filaments is electrically coupled to each other and to an activating voltage source in parallel. Each of the filaments emits a focused electron beam directed to a different predetermined spot on the anode upon application of a predetermined voltage between the cathode and the anode, thereby causing the anode to generate x-rays. Each of the plurality of spaced apart cavities is aimed at the anode so that each predetermined spot on the anode is separated from each other spot by a gap that is not impacted by an electron beam.

An x-ray generating unit includes an x-ray tube that is substantially transparent to x-rays. A cathode is within the x-ray tube and defines a plurality of spaced apart cavities. An anode includes a material that emits x-rays when impacted by electrons. A plurality of filaments is each disposed in a different one of the cavities. Each of the filaments is electrically coupled to each other and to an activating voltage source in parallel. Each of the filaments emits a focused electron beam directed to a different predetermined spot on the anode upon application of a predetermined voltage between the cathode and the anode, thereby causing the anode to generate x-rays. Each of the plurality of spaced apart cavities is aimed at the anode so that each predetermined spot on the anode is separated from each other spot by a gap that is not impacted by an electron beam.

An x-ray tube having at least one focusing cup and an anode. The x-ray tube may have a first filament positioned in a first location between the focusing cup and the anode, the first filament having a first size, and a second filament positioned in a second location between the focusing cup and anode, the second filament having a second size that is substantially the same as the first size. The x-ray tube may also include a switching mechanism configured to engage the second filament upon failure of the first filament.

An X-ray source for emitting an X-ray beam is proposed. The X-ray source comprises an anode and an emitter arrangement comprising a cathode for emitting an electron beam towards the anode and an electron optics for focusing the electron beam at a focal spot on the anode. The X-ray source further comprises a controller configured to determine a switching action of the emitter arrangement and to actuate the emitter arrangement to perform the switching action, the switching action being associated with a change of at least one of a position of the focal spot on the anode, a size of the focal spot, and a shape of the focal spot. The controller is further configured to predict before the switching action is performed, based on the determined switching action, the size and the shape of the focal spot expected after the switching action. Further, the controller is configured to actuate the electron optics to compensate for a change of the size and the shape of the focal spot induced by the switching action.

An X-ray source for emitting an X-ray beam is proposed. The X-ray source comprises an anode and an emitter arrangement comprising a cathode for emitting an electron beam towards the anode and an electron optics for focusing the electron beam at a focal spot on the anode. The X-ray source further comprises a controller configured to determine a switching action of the emitter arrangement and to actuate the emitter arrangement to perform the switching action, the switching action being associated with a change of at least one of a position of the focal spot on the anode, a size of the focal spot, and a shape of the focal spot. The controller is further configured to predict before the switching action is performed, based on the determined switching action, the size and the shape of the focal spot expected after the switching action. Further, the controller is configured to actuate the electron optics to compensate for a change of the size and the shape of the focal spot induced by the switching action.

X-ray transparent insulation can be sandwiched between an x-ray window and a ground plate. The x-ray transparent insulation can include aluminum nitride, boron nitride, or polyetherimide. The x-ray transparent insulation can include a curved side. The x-ray transparent insulation can be transparent to x-rays and resistant to x-ray damage, and can have high thermal conductivity. An x-ray window can have high thermal conductivity, high electrical conductivity, high melting point, low cost, and matched coefficient of thermal conductivity with the anode. The x-ray window can be made of tungsten. For consistent x-ray spot size and location, a focusing plate and a filament can be attached to a cathode with an open channel of the focusing plate aligned with a longitudinal dimension of the filament. Tabs of the focusing plate bordering the open channel can be bent to align with a location of the filament.