Abstract: A self-lubricated sliding bearing for a rotary X-ray tube comprises a first bearing member, a second bearing member configured to concentrically enclose a portion of the first bearing member, and a lubricant comprised in a gap between cooperating surfaces of the first bearing member and the second bearing member. The cooperating surface of the second bearing member or the first bearing member comprises a first region comprising a pumping pattern configured to pump the lubricant. The cooperating surface of the second bearing member or the first bearing member comprises a second region having a modified pumping pattern or a smooth surface.

Abstract: A lithography method in semiconductor fabrication is provided. The method includes generating a plurality of drops of a target material through a plurality of nozzles, adjacent two of the plurality of nozzles having a distance less than a width of a first one of the adjacent two of the plurality of nozzles, wherein the plurality of drops are aggregated to an elongated droplet; generating a laser pulse to convert the elongated droplet into plasma that generates an extreme ultraviolet (EUV) radiation; exposing a semiconductor substrate to the EUV radiation.

Abstract: A light source includes a rotatable drum, an exhaust tube coupled to the rotatable drum to exhaust nitrogen gas from an interior of the rotatable drum, a feed tube situated within the exhaust tube to provide liquid nitrogen to the interior of the rotatable drum, and a casing to surround at least a portion of the exhaust tube. The light source also includes a rotary air bearing between the exhaust tube and the casing, to allow the exhaust tube to rotate with the rotatable drum.

Abstract: An optical apparatus is provided for manipulating light from x-ray sources (e.g., free electron lasers). In some embodiments, the optical apparatus includes a first capillary optic having a first longitudinal axis and a second capillary optic having a second longitudinal axis that is angled with respect to the first longitudinal axis. The second capillary optic is positioned to receive light directly from the first capillary optic.

Abstract: Methods and systems are provided for plasma confinement utilizing various electrode and valve configurations. In one example, a device includes a first electrode positioned to define an outer boundary of an acceleration volume, a second electrode arranged coaxially with respect to the first electrode and positioned to define an inner boundary of the acceleration volume, at least one power supply to drive an electric current along a Z-pinch plasma column between the first second electrodes, and a set of valves to provide gas to the acceleration volume to fuel the Z-pinch plasma column, wherein an electron flow of the electric current is in a first direction from the second electrode to the first electrode. In additional or alternative examples, a shaping part is conductively connected to the second electrode to, in a presence of the gas, cause a gas breakdown of the gas to generate a sheared flow velocity profile.

Abstract: According to some aspects, a monochromatic x-ray source is provided. The monochromatic x-ray source comprises an electron source configured to generate electrons, a primary target arranged to receive electrons from the electron source to produce broadband x-ray radiation in response to electrons impinging on the primary target, and a secondary target comprising at least one layer of material capable of producing monochromatic x-ray radiation in response to incident broadband x-ray radiation emitted by the primary target.

Abstract: Some embodiments of the present disclosure provide a method that includes colliding a laser with an electron beam to produce backscattered x-rays while the electron beam is traversing a circular arc. This backscattering process is inverse Compton scattering (ICS). ICS x-rays are emitted in the same direction as the electrons. Because this ICS direction is changing as a function of time, the position of the x-ray beam on a detector will change depending on the timing of electron/laser collision. This position change is easily detected and converted to a timing measurement sensitive at the femtosecond scale, converting a very difficult timing measurement of laser pulse, electron pulse, and x-ray pulse synchronization into a simple and robust position measurement.

Abstract: An extreme ultraviolet light source apparatus includes a disc-shaped cathode rotating about an axis, a disc-shaped anode rotating about an axis, an energy beam irradiation device irradiating a plasma raw material on the cathode with an energy beam to vaporize the plasma raw material, a power supply for causing a discharge between the cathode and the anode for generating a plasma in the gap between the cathode and the anode to emit extreme ultraviolet light, and an irradiation position adjusting mechanism for adjusting a position at which the cathode is irradiated with the energy beam. The cathode, the anode, and the irradiation position adjusting mechanism are accommodated in a housing. A photography device is disposed outside the housing and is configured to photograph a visible-light image of a vicinity of the cathode and the anode, the vicinity including visible light emitted from the plasma.

Abstract: A shutter is provided near the immediate focus of a lithography apparatus in order to deflect tin debris generated by a source side of the apparatus away from a scanner side of the apparatus and towards a debris collection device. The activation of the shutter is synchronized with the generation of light pulses so as not to block light from entering the scanner side.

Abstract: Systems, methods, and computer software are disclosed for acquiring images during delivery of a radiation beam, the images capturing at least a portion of a shape representative of a radiation field generated by a radiation delivery system that includes a radiation source configured to deliver the radiation beam.

Abstract: A system for generating X-ray beams from a liquid target includes a vacuum chamber, a diamond window assembly, an electron source, a target material flow system, and an X-ray detector/imager. An electron beam from the electron source travels through the diamond window assembly and into a dynamic target material of the flow system. Preferably, the dynamic target material is lead bismuth eutectic in a liquid state. Upon colliding with the dynamic target material, X-rays are generated. The generated X-rays exit through an X-ray exit window to be captured by the X-ray detector/imager. Since the dynamic target material is constantly in fluid motion within a pipeline of the flow system, the electron beam always has a new target area which is at a controlled operational temperature and thus, prevents overheating issues. By providing a small focus area for the electron beams, the overall imaging resolution of the X-rays is also improved.

Abstract: A system for generating X-ray beams from a liquid target includes a vacuum chamber, a diamond window assembly, an electron source, a target material flow system, and an X-ray detector/imager. An electron beam from the electron source travels through the diamond window assembly and into a dynamic target material of the flow system. Preferably, the dynamic target material is lead bismuth eutectic in a liquid state. Upon colliding with the dynamic target material, X-rays are generated. The generated X-rays exit through an X-ray exit window to be captured by the X-ray detector/imager. Since the dynamic target material is constantly in fluid motion within a pipeline of the flow system, the electron beam always has a new target area which is at a controlled operational temperature and thus, prevents overheating issues. By providing a small focus area for the electron beams, the overall imaging resolution of the X-rays is also improved.

Abstract: The invention discloses X-ray machine ray tube heat dissipation device which comprises a heat dissipation pool and an X-ray machine ray tube arranged in the heat dissipation pool, wherein the heat dissipation pool is provided with a water inlet and a water outlet, and the water outlet of the heat dissipation pool is communicated with the water inlet of water tank.

Abstract: An X-ray imaging apparatus and a consumption level estimation method for an X-ray source, which estimate the consumption level of an X-ray source without measuring grid voltage. An X-ray control part includes: a tube current value setting part setting a tube current value supplied to an X-ray source; a tube current value measurement part measuring a cathode current value as the tube current value by a cathode current detector; a time measurement part measuring the time when the tube current value is set by the tube current value setting part and the time when the tube current value measured by the tube current value measurement part reaches the set value; and a consumption level estimation part estimating the consumption level of a cathode in the X-ray source based one the time until the tube current value reaches the set value after the tube current value has been set.

Abstract: The present disclosure is directed to laser produced plasma light sources having a target material, such as xenon, that is coated on the outer surface of a drum. Bearing systems rotate the drum that have structures for reducing leakage of contaminant material and/or bearing gas into the LPP chamber. Injection systems are disclosed for coating and replenishing target material on the drum. Wiper systems are disclosed for preparing the target material surface on the drum, e.g. smoothing the target material surface. Systems for cooling and maintaining the temperature of the drum and a housing overlying the drum are also disclosed.

Abstract: A method for controlling an X-ray source configured to emit, from an X-ray spot on a target, X-ray radiation generated by an interaction between an electron beam and the target, wherein the X-ray spot is determined by the field of view of an X-ray optical system of the X-ray source. The method includes providing the target, providing the electron beam forming an electron spot on the target and interacting with the target to generate X-ray radiation, and adjusting a width and total power of the electron beam such that a maximum of the power density profile in the electron spot is below a predetermined limit, and such that a total power delivered to the target in the X-ray spot is increased.

Abstract: The present disclosure is directed to a device having a nozzle for dispensing a liquid target material; one or more intermediary chamber(s), each intermediary chamber positioned to receive target material and formed with an exit aperture to output target material for downstream irradiation in a laser produced plasma (LPP) chamber. In some disclosed embodiments, control systems are included for controlling one or more of gas temperature, gas pressure and gas composition in one, some or all of a device's intermediary chamber(s). In one embodiment, an intermediary chamber having an adjustable length is disclosed.

Abstract: An electron emission structure according to embodiments of the inventive concept includes a cathode electrode and electron emission yarns each having a yarn shape and disposed in the cathode electrode. Here, the cathode electrode includes a plurality of first conductive panels spaced apart from each other in a first direction and at least one second conductive panel that crosses the first conductive panels in the first direction. Also, each of the first conductive panels includes at least one groove at an upper portion thereof. The second conductive panel is inserted to the groove of each of the first conductive panels. Each of the electron emission yarns is disposed between the first conductive panels. Each of the electron emission yarns contacts the second conductive panel. Each of the electron emission yarns is mechanically fixed and vertically aligned as well as arranged regularly by the second conductive panel and one pair of adjacent first conductive panels of the first conductive panels.

Abstract: A laser-produced plasma X-ray system includes a liquid metal flow system enclosed within a low-pressure chamber, the flow system including a liquid metal, wherein in at least one location on the liquid metal forms a metal target beam, a circulation pump within the flow system for circulating the liquid metal, a laser pulse emitter configured to transmit a plurality of laser pulses into the chamber via a laser window, focusing optics, located between the emitter and the metal target beam, the focusing optics directing the laser pulses to strike the metal target beam at a target location to form X-ray pulses, and an X-ray window positioned within the chamber to allow the X-ray pulses to exit the chamber.

Abstract: A modular laser-produced plasma X-ray system includes a liquid metal flow system enclosed within a low-pressure chamber, the flow system including a liquid metal, wherein in at least one location on the liquid metal forms a metal target directly illuminated by laser pulses, a circulation pump within the liquid metal flow system for circulating the liquid metal, a laser pulse emitter configured to transmit laser pulses into the chamber via a laser window, focusing optics, located between the emitter and the metal target, the focusing optics directing the laser pulses to strike the metal target at a target location to form X-ray pulses, and an X-ray window positioned within the chamber to enable the X-ray pulses to exit the chamber.

Abstract: An x-ray source for a backscatter imager can include a first electron beam (e-beam) emitter for emitting a first e-beam and at least a second e-beam emitter for emitting at least a second e-beam. The first and second e-beam emitters can be powered by a at least one power supply, and can be configured to direct the first e-beam and the second e-beam toward an anode. An interaction of the anode with the first and second e-beams produces x-rays. The x-ray source is configured to output an amount of x-rays equivalent to a conventional x-ray source that includes a single e-beam emitter. However, because the x-ray source uses at least two e-beam emitters and a single anode, the power source required to power the e-beam emitters can operate at a lower wattage than a conventional power source powering the single e-beam emitter. The x-ray source is thus lighter in weight and outputs less radiation than conventional systems with a comparable x-ray output.

Abstract: A semiconductor device includes a silicon carbide layer, a metal carbide layer arranged over the silicon carbide layer, and a solder layer arranged over and in contact with the metal carbide layer.

Abstract: A support apparatus comprises processing circuitry. The processing circuitry is configured to calculate, based on an irradiation plan with radiation on a target site of a subject, a recommendation degree of disposition of an ultrasonic probe configured to scan the target site at irradiation with the radiation, for each position in the subject. And the processing circuitry is configured to notify an operator of the recommendation degree in association with a position in the subject.

Abstract: Embodiments of the disclosed system and method provide for generating a multiple-energy X-ray pulse. A beam of electrons is generated with an electron gun and modulated prior to injection into an accelerating structure to achieve at least a first and second specified beam current amplitude over the course of respective beam current temporal profiles. A radio frequency field is applied to the accelerating structure with a specified RF field amplitude and a specified RF temporal profile. The first and second specified beam current amplitudes are injected serially, each after a specified delay, in such a manner as to achieve at least two distinct energies of electrons accelerated within the accelerating structure during a course of a single RF-pulse. The beam of electrons is accelerated by the radio frequency field within the accelerating structure to produce accelerated electrons which impinge upon a target for generating Bremsstrahlung X-rays.

Abstract: An extreme ultra-violet (EUV) lithography system includes an EUV source and EUV scanner. A droplet generator provides a droplet stream in the EUV source. A gas shield is configured to surround the droplet stream. When a laser reacts a droplet in the stream EUV radiation and ionized particles are produced. The gas shield can reduce contamination resulting from the ionized particles by conveying the ionized particles to a droplet catcher. Components of the EUV source may be biased with a voltage to repel or attract ionized particles to reduce contamination from the ionized particles.

Abstract: According to some aspects, a monochromatic x-ray source is provided. The monochromatic x-ray source comprises an electron source configured to generate electrons, a primary target arranged to receive electrons from the electron source to produce broadband x-ray radiation in response to electrons impinging on the primary target, and a secondary target comprising at least one layer of material capable of producing monochromatic x-ray radiation in response to incident broadband x-ray radiation emitted by the primary target.

Abstract: Some embodiments include a structure, comprising: an insulator forming at least a part of a wall of a vacuum chamber, the insulator having a first end and a second end wider than the first end; a first conductive structure disposed at the first end of the insulator; and a second conductive structure disposed at the second end of the insulator, contacting the insulator, and including at least a portion surrounded by the insulator; wherein: a portion of an outer surface of the insulator extends radially outward from a triple junction between the insulator, the second conductive structure, and a medium contacting the outer surface of the insulator.

Abstract: A system for generating X-ray beams from a liquid target includes a vacuum chamber, a diamond window assembly, an electron source, a target material flow system, and an X-ray detector/imager. An electron beam from the electron source travels through the diamond window assembly and into a dynamic target material of the flow system. Preferably, the dynamic target material is lead bismuth eutectic in a liquid state. Upon colliding with the dynamic target material, X-rays are generated. The generated X-rays exit through an X-ray exit window to be captured by the X-ray detector/imager. Since the dynamic target material is constantly in fluid motion within a pipeline of the flow system, the electron beam always has a new target area which is at a controlled operational temperature and thus, prevents overheating issues. By providing a small focus area for the electron beams, the overall imaging resolution of the X-rays is also improved.

Abstract: A target supply device includes a vibrating element driven by a square wave electric signal and configured to generate a droplet of a target substance by vibrating the target substance to be output from a nozzle through a vibration propagating path; a temperature adjusting mechanism configured to adjust, to a specified temperature, a temperature of a vibration propagating path member including at least part of the vibration propagating path; a droplet detecting unit configured to output a signal containing information on a droplet detection interval indicating a time interval of droplets continuously generated; and a control unit configured to determine, based on the droplet detection interval, an operation specified temperature that is the specified temperature of the vibration propagating path member and an operation duty value that is a duty value of the electric signal used for driving the vibrating element when the droplet is irradiated with the laser beam.

Abstract: Intraoral three-dimensional (3D) tomosynthesis imaging systems, methods, and non-transitory computer readable media are used to generate one or more two-dimensional (2D) x-ray projection images and to reconstruct, using a computing platform, the one or more 2D x-ray projection images into one or more 3D images of an object, such as teeth of a patient, which can then be displayed on a monitor in order to enhance diagnostic accuracy of dental disease. The intraoral 3D tomosynthesis imaging system can include a wall-mountable control unit connected to one end of an articulating arm, the other end of which is connected to an x-ray source, which is configured to generate x-ray radiation that is acquired by an x-ray detector held at a desired position by an x-ray detector holder that is removably coupled to a collimator at an emission region of the x-ray source.

Abstract: The present disclosure relates to systems and methods for positioning an X-ray scanner. The systems may perform the methods to obtain an origin related to an X-ray scanner; determine a coordinate system based on the origin; determine coordinates of a second location of the X-ray scanner based on the origin and the coordinate system; obtain coordinates of a first location based on the origin and the coordinate system; and determine, based on the origin and the coordinates of the second location, positioning information of the X-ray scanner configured to cause the X-ray scanner to be positioned at the first location from the second location of the X-ray scanner.

Abstract: Systems and methods for generating tunable x-ray emissions including a tunable x-ray source that includes a driver, such as a laser, configured to generate one or more driver pulses, such as one or more laser pulses, and a target source configured to emit a target material. The target source is arranged so that the emitted target material intersects a propagation axis of the driver pulse(s) and the target source may be configured so that the emitted target material has a tailored density profile along the propagation axis of the driver pulse(s), the tailored density profile along the propagation axis having a first density peak region followed by a lower density region followed by a second density peak region, e.g., in an “M” shape.

Abstract: An X-ray tube includes: a vacuum housing configured to include an internal space which is vacuum; a target unit configured to be disposed in the internal space, and include a target that generates an X-ray by using an electron beam incident therein, and a target support unit that supports the target, the X-ray generated by the target being transmitted through the target support unit; and an X-ray emission window configured to be so provided as to face the target support unit, and seal an opening of the vacuum housing, the X-rays transmitted through the target support unit being transmitted through the X-ray emission window. At least a part of the X-ray emission window is in contact with the target support unit.

Abstract: Embodiments of the present invention provide an improved method and system for assessing non-uniformity of features in the measurement area (within the beam spot) on a semiconductor structure, (e.g. wafer), such as a non-uniform film thickness. The scattering from non-uniform features is modeled. Post-processing the residual of theoretical and collected spectra is performed to assess a measure of non-uniformity from within an incident spot beam of a spectrum acquisition tool.

Abstract: A system and method for adaptive imaging include a shape sensing system (115, 117) coupled to an interventional device (102) to measure spatial characteristics of the interventional device in a subject. An image module (130) is configured to receive the spatial characteristics and generate one or more control signals in accordance with the spatial characteristics. An imaging device (110) is configured to image the subject in accordance with the control signals.

Abstract: The present invention relates to a modulation of X-ray radiation for the purposes of imaging an object of interest. For the modulation, the X-ray radiation provided by an X-ray source (12) is in part totally reflected by a mirror (20). Thus, an X-ray radiation at an object receiving space (16) is formed by an unreflected X-ray radiation (24) and a reflected X-ray radiation (26). The mirror (20) is displaceable by an actuator (28), such that the intensity of the reflected X-ray radiation (26) can be adjusted, in particular to a density of the object to be imaged.

Abstract: An X-ray tube includes: a vacuum housing configured to include an internal space which is vacuum; a target unit configured to be disposed in the internal space, and include a target that generates an X-ray by using an electron beam incident therein, and a target support unit that supports the target, the X-ray generated by the target being transmitted through the target support unit; an X-ray emission window configured to be so provided as to face the target support unit, and seal an opening of the vacuum housing, the X-rays transmitted through the target support unit being transmitted through the X-ray emission window; an elastic member configured to press the target unit in such a direction as to approach the X-ray emission window; and a target shift unit configured to shift the target unit pressed by the elastic member in a direction crossing an incidence direction of the electron beam.

Abstract: A method for determining the geometry of a structure on an object at least by using a computer tomography sensor system comprising at least a radiation source, a mechanical axis of rotation, and a detector, preferably a planar detector, wherein surface measurement points are generated by the computer tomography sensor system, for example in the region of material transitions. In order to select the surface measurement points to be used for the determination of a geometry feature by using any target geometry, in particular without the availability of a CAD model being necessary, according to the invention, in order to determine the geometry features, surface measurement points are used which are associated with the geometry features to be determined on the basis of specifiable rules and the geometry features are determined from the associated surface measurement points.

Abstract: The present disclosure is directed to a device having a nozzle for dispensing a liquid target material; one or more intermediary chamber(s), each intermediary chamber positioned to receive target material and formed with an exit aperture to output target material for downstream irradiation in a laser produced plasma (LPP) chamber. In some disclosed embodiments, control systems are included for controlling one or more of gas temperature, gas pressure and gas composition in one, some or all of a device's intermediary chamber(s). In one embodiment, an intermediary chamber having an adjustable length is disclosed.

Abstract: An X-ray tube includes an electron gun, a target that generates X-rays, and a vacuum housing that accommodates the electron gun and the target. The vacuum housing has a metal portion having an X-ray emission window, and an insulation valve connected to the metal portion. The metal portion has a cylinder portion in which the X-ray emission window is provided and which surrounds a tube axis of the vacuum housing, and a tapered portion which is connected to an end portion of the cylinder portion, surrounds the tube axis, and protrudes such that a connection part between the metal portion and an insulation valve is covered. The tapered portion has a shape increased in diameter such that a separation distance between a distal end portion and the tube axis is longer than a separation distance between a base end portion and the tube axis.

Abstract: A support structure and an imaging component are provided in an imaging system. The imaging component comprises a port extension that frames an opening for x-ray emission. The support structure comprises a recess for receiving the port extension, the recess also framing an opening for x-ray transmission. The imaging system may be a computed tomography (CT) imaging system, x-ray diagnostic system, or other imaging system.

Abstract: The circular X-ray tube for the irradiation of the object (1) by X-radiation comprising the circular body (2) and at least two friction elements that rub together whereby forming a triboluminescent source of X-radiation. The one friction element comprises at least one circumferential element (3) arranged on the external circumferential side of the circular body (2) of the X-ray tube and the other friction element comprises at least one pressure element (4) that is pressed against the circumferential element (3), where the pressure element (4) is adapted for dragging upon the circumferential element (3), and/or at least one circumferential element (3) is adapted for pulling through under the pressure element (4). The X-ray instrument utilizes the circular X-ray tube and the imaging detectors (7) of ionizing radiation.

Abstract: In one embodiment, an x-ray tube 15 can be used closer to a sample. An angle A1 between an anode axis 02 and an electron-beam axis 01 can be ?10° and ?80° and an angle A2 between the anode axis 02 and an x-ray axis 03 can be ?10° and ?80°. In another embodiment, a cap 20 on an anode 12 can block x-rays emitted in undesired directions. The cap 20 can include an internal cavity 24, an electron-beam hole 21, an anode hole 22, and an x-ray hole 23. In another embodiment, an electrical connection between an x-ray tube 15 and a power supply 18 can be reliable and easy to manufacture. The anode 12 can include a hole 31 at an end of the anode 12 sized and shaped for insertion of an electrical connector 32.

Abstract: A X-ray generating device includes a chamber, a rotating body in the chamber, a starting material storage vessel for storing a target starting material in liquid form, and a starting material supply mechanism for applying the target starting material onto a surface of the rotating body. The X-ray generating device also includes an energy beam inlet window disposed at an opening of the chamber and configured to transmit an energy beam, which will be directed onto the target starting material on the surface of the rotating body and introduce the energy beam from the exterior of the chamber to the interior of the chamber, and an X-ray outlet window disposed at the opening of the chamber and configured to transmit the X-rays, which are generated upon irradiating the target starting material with the energy beam, and allow the X-rays to proceed to the exterior of the chamber.

Abstract: A medical device includes: a base; a positioner coupled to the base; an accelerator coupled to the positioner, wherein the positioner is operable to rotate the accelerator relative to the base about at least two axes; and a power source coupled to the accelerator, the power source configured to provide microwave power for the accelerator, wherein a position of the power source relative to the base remains fixed during movement of the accelerator. A medical device includes: a base; a positioner coupled to the base; an accelerator coupled to the positioner; a power source configured to provide microwave power for the accelerator, wherein a position of the source relative to the base remains fixed during movement of the accelerator; and a waveguide for coupling the power source and the accelerator; wherein the waveguide has a first segment with a first cross section, the first cross section being a circular cross-section.

Abstract: A target supply device according to an aspect of the present disclosure includes a vibration element configured to generate a droplet by vibrating a target substance to be output from a nozzle 80, a droplet detection unit configured to detect the droplet, and a control unit 70. A first detection threshold and a second detection threshold to be compared with a detection signal from the droplet detection unit are set to the control unit 70. The first detection threshold is used to generate a light emission trigger for a laser beam. The second detection threshold has a smaller absolute value from a base line of the detection signal than the first detection threshold. The control unit 70 calculates an evaluation parameter for a satellite based on the detection signal and the second detection threshold, and determines a duty value of an electric signal suitable for operation of the vibration element based on the evaluation parameter.

Abstract: The present invention provides an X-Ray emitting device that comprises a focusing electrode composed of a ceramic-based material, which can be manufactured by a simple process and is excellent in durability.

Abstract: An embodiment of an X-ray tube is described that comprises an outer cylinder; a window positioned on an end of the outer cylinder; an electron gun comprising an emission orifice, wherein the electron gun is coupled to a side of the outer cylinder at an angle that orients the emission orifice toward the window; and a rod centrally positioned within the outer cylinder, wherein the rod comprises a concave geometry at a distal end proximal to the electron gun and a target surface configured at an angle that orients the target surface towards the emission orifice, wherein the concave geometry is configured to position the target surface to have a focal spot size of an electron beam from the emission orifice in range of about 2-6 ?m.

Abstract: An extreme ultra-violet (EUV) lithography system includes an EUV source and EUV scanner. A droplet generator provides a droplet stream in the EUV source. A gas shield is configured to surround the droplet stream. When a laser reacts a droplet in the stream, EUV radiation and ionized particles are produced. The gas shield can reduce contamination resulting from the ionized particles by conveying the ionized particles to a droplet catcher. Components of the EUV source may be biased with a voltage to repel or attract ionized particles to reduce contamination from the ionized particles.

Abstract: Methods of investigating a specimen using tomographic imaging include directing a beam of radiation through a specimen and onto a detector, thereby generating an image of the specimen. The directing is repeated for different specimen orientations relative to the beam, thereby generating a corresponding set of images. An iterative mathematical reconstruction technique is used to convert the images into a tomogram. The reconstruction is mathematically constrained to curtail a solution space using three-dimensional SEM imagery of at least a part of the specimen that overlaps the tomogram by requiring iterative results of the reconstruction to be consistent with pixel values derived from the SEM imagery.