WO2011044199A1 - Sources de rayons x en panneaux plats à adressage numérique - Google Patents

Sources de rayons x en panneaux plats à adressage numérique Download PDF

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Publication number
WO2011044199A1
WO2011044199A1 PCT/US2010/051580 US2010051580W WO2011044199A1 WO 2011044199 A1 WO2011044199 A1 WO 2011044199A1 US 2010051580 W US2010051580 W US 2010051580W WO 2011044199 A1 WO2011044199 A1 WO 2011044199A1
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WO
WIPO (PCT)
Prior art keywords
irradiation chamber
cathode
anode
ray
operable
Prior art date
Application number
PCT/US2010/051580
Other languages
English (en)
Inventor
Mark Eaton
Mitali More
Babu Chalamala
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Stellarray, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Stellarray, Inc. filed Critical Stellarray, Inc.
Publication of WO2011044199A1 publication Critical patent/WO2011044199A1/fr

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K5/00—Irradiation devices
    • G21K5/02—Irradiation devices having no beam-forming means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/06—Cathodes
    • H01J35/065—Field emission, photo emission or secondary emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/06—Cathode assembly
    • H01J2235/062—Cold cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/06—Cathode assembly
    • H01J2235/068—Multi-cathode assembly
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/08—Targets (anodes) and X-ray converters
    • H01J2235/086—Target geometry
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/18—Windows, e.g. for X-ray transmission

Definitions

  • the present disclosure relates generally to the assembly and fabrication of a digitally addressed x-ray source, and more particularly, to the construction of a matrix addressable, wide area x-ray sources and their application in digitally addressed x-ray imaging systems.
  • Patents 6,760,407 and 6,876,724 disclose examples of larger X-ray tubes using cold cathodes for other purposes, such as imaging.
  • cold cathodes for other purposes, such as imaging.
  • Several types of field emission cold cathodes have been developed which can be substituted for the single hot filament cathodes. These include arrays of semiconductor or metal micro tips, flat cathodes of low work function materials and arrays of carbon or other nanotubes. While they offer several improvements, these cold cathode X-ray tubes share the limitations of their hot filament tube predecessors in being essentially point sources of X-rays.
  • Patent 6,333,968 discloses a transmission cathode for X-ray production in which current from the cathode generates X-rays on a target opposite the cathode, the radiation then transmitting through the cathode.
  • the single cathode covers substantially the entire exit area for the radiation. This limits the size of the radiation exit area to the size of the cathode, making this type of source essentially a point source of X-rays. It also limits the area of the anode to that of the cathode, making it difficult to produce more than small levels of X-ray flux owing to the difficulty of extracting heat from this small area.
  • Another transmission cathode is disclosed in US Patent 7469040, for a pipelike source in which the cathode surrounds an inner chamber through which can pass material to be irradiated.
  • an X-ray source had been disclosed in US patent 7447298 having a thermionic or cold cathode array inside a vacuum enclosure, which can direct e-beam current to a thin film X-ray target disposed on an exit window located above the cathode array with reference to the direction of the e-bam and X-ray fluxes, or, with a second cathode array, to a wide area anode located below the first cathode array, the second cathode arrays and the exit window with the thin-film anode.
  • This source will have the heat dissipation limitations as discussed above for the thin-film X-ray target.
  • X-rays produced by the lower, "reflective" anode will be attenuated first by the cathode arrays and their support structures, and then the thin-film X-ray target, resulting in an inefficient system.
  • the second anode while it can be thicker and have higher heat dissipation capacity than a thin-film anode, is inside the vacuum enclosure. The heat must therefore be transferred through the vacuum enclosure, which will limit the electrical and radiative flux power that can be achieved with this source.
  • X-ray treatment can be used to decontaminate biological or chemical agents.
  • Chemical and gas methods for the remediation of hazards such as anthrax, ricin, or smallpox suffer a number of limitations, including hazards to human operators during their application, lingering hazards after they have been applied, limited effectiveness, long set-up and application times and destruction of electronic and other equipment in the treatment area.
  • X-rays can decontaminate biological and chemical hazards through ionization, thereby decontaminating biohazards in a matter of minutes or hours, compared to days and weeks with chemical and gas methods.
  • X-rays have the further advantage of being able to penetrate objects or surfaces which may occlude hazardous material.
  • point sources of X- rays have limited heat dissipation capacity and therefore will be limited in their ability to cover a large decontamination or sterilization area.
  • Sources of X-ray flux are needed which are broad, power efficient and can cover wide areas which may have been contaminated.
  • Embodiments of the present disclosure are directed to systems and methods that are further described in the following description and claims. Advantages and features of embodiments of the present disclosure may become apparent from the description, accompanying drawings and claims.
  • an apparatus and method for the X-ray irradiation of materials includes an irradiation chamber, a number of flat electromagnetic (X-ray) sources, a support mechanism, a heat transfer system, and a shielding system.
  • a shielded portal within the shielding system allows access to an interior volume of the irradiation chamber.
  • the shielded portal allows materials to be placed in and withdrawn from the irradiation chamber. When closed, the shielded portal allows a continuous shielded boundary of the interior volume of the irradiation chamber.
  • the electromagnetic sources are positioned on or embedded with interior surfaces of the irradiation chamber.
  • Yet another embodiment of the present disclosure provides another system for the X-ray irradiation of materials.
  • This system includes an irradiation chamber, a number of flat X-ray sources, a transport mechanism, a low attenuation support mechanism, a heat transfer system, a shielding system, and a process controller.
  • the irradiation chamber has an inner volume wherein the flat X-ray sources are positioned within or on the interior surfaces of the irradiation chamber such that the flat X-ray sources may irradiate the interior volume of the irradiation chamber.
  • the transport mechanism allows materials to travel to and from the irradiation chamber.
  • FIG. 1A shows the directing of an electron beam current at an X-ray anode so as to produce X-rays at an angle to the current beam, the X-rays then exiting a window which is separate from the electron beam source;
  • FIG. 1C shows the directing of an electron beam current from a cathode array formed on an exit window at an X-ray anode so as to produce X-rays which then pass by or through the cathodes as the X-rays exit the window in accordance with embodiments of the preset disclosure;
  • FIG. 3 provides a diag ram of an irradiation chamber in accordance with embodiments of the present disclosure
  • FIG. 4 depicts a tiled arrangement 700 of x-ray panels in accordance with embodiments of the present disclosure
  • FIG. 5 shows a typical x-ray source in a point source geometry in accordance with embodiments of the present disclosure
  • FIG. 6 shows the large area flat panel x-ray source with a matrix addressed electron beam source and a vacuum assembly in accordance with embodiments of the present disclosure
  • FIGs. 8A and 8B shows a digitally addressed x-ray source where electron beams are focused at a desired location using focusing electrode structures which are assembled as part of the vacuum assembly in accordance with embodiments of the present disclosure
  • FIGs. 9A and 9B illustrates the application of the digitally addressed x-ray source in breast tomosynthesis system with a source to detector distance of 60mm and 30mm in accordance with embodiments of the present disclosure.
  • FIG. 10 illustrates the application tiled DAXS panels in a small animal imaging system in accordance with embodiments of the present disclosure.
  • FIG. 11 provides a logic flow diagram of a method of irradiating materials in accordance with embodiments of the present disclosure.
  • a conventional x-ray tube includes an anode, grid, and cathode assembly.
  • the cathode assembly generates an electron beam which is directed to a target, by an applied electric field established by the anode.
  • the target in turn emits x-ray radiation in response to the incident electron beam.
  • the present disclosure provides an apparatus and method for the X-ray irradiation of materials.
  • This apparatus includes an irradiation chamber, a number of flat electromagnetic (X-ray) sources, a support mechanism, a heat transfer system, and a shielding system.
  • a shielded portal within the shielding system allows access to an interior volume of the irradiation chamber.
  • the shielded portal allows materials to be placed in and withdrawn from the irradiation chamber. When closed, the shielded portal allows a continuous shielded boundary of the interior volume of the irradiation chamber.
  • the electromagnetic sources are positioned on or embedded with interior surfaces of the irradiation chamber.
  • These electromagnetic sources may generate an electromagnetic flux, such as an X-ray flux, where this flux is used to irradiate the interior volume of the irradiation chamber and any materials placed therein.
  • the materials placed within the interior of the chamber may be supported by a low attenuation support mechanism. This low attenuation support mechanism does not substantially reduce the X-ray flux intended to irradiate the materials placed within the interior volume of the irradiation chamber.
  • the irradiation chamber may have a heat transfer system thermally coupled to the irradiation chamber and electromagnetic sources in order to remove heat from the interior surfaces of the irradiation chamber.
  • the shielding system external to the irradiation chamber prevents unwanted radiation from escaping from within the irradiation chamber.
  • Cathode 102 and anode target 106 are enclosed in a vacuum tube or envelope which is commonly made of glass, ceramic or metal.
  • X-ray flux which does not exit window 110 is absorbed in anode target 106, the vacuum envelope material, the exit window, or elsewhere in the source, this absorption process generating waste heat.
  • Anode targets 106 have been made of many different elemental metals or alloys, the most common ones being tungsten, molybdenum, copper and tungsten-rhenium alloy. To reduce damage from electron beam impact and heating, anode 106 has been made as a disk with a beveled edge to provide a target angled in relation to beam current 104.
  • This disk is connected to a metal rotor which is spun as part of an induction motor by a stator external to the vacuum tube or envelope.
  • the electrical potential between cathode 102 and anode 106 varies widely depending on the desired energy of X-ray flux 108, higher potential producing higher energy X-rays. The higher the X-ray energy, the more ability the flux has to penetrate objects. Potentials used in imaging applications commonly vary between 30keV and 200 keV. Depending on the material composition of anode target 106, different characteristic line energies, and amounts of characteristic line and Bremsstrahlung radiation, will be produced. Higher Z materials produce higher total amounts of radiation.
  • Exit windows 110 are commonly made of beryllium or other low Z materials with low coefficients of X-ray absorption, but they may be made of numerous other materials including various type of glass. In some prior art X-ray sources, the glass tube itself serves as the exit window. Numerous variations and combinations of these major elements of an X-ray source are well known.
  • FIG. IB depicts another method that disposes a thin anode target layer 106 on exit window 110.
  • a wide source of electron beam current 104 is produced by a wide area cathode 102 which impacts broadly over anode target layer 106.
  • X-ray flux is generated in all directions from the anode target layer, a portion of the flux passing through the thin target layer and then the exit window as X-ray flux 108.
  • Embodiments of the present disclosure provide a different approach and method for the generation of X- rays. This is shown conceptually in FIG. 1C and in FIG. 2.
  • FIG. 1C shows the directing of an electron beam current from a cathode array formed on an exit window at an X-ray anode so as to produce X-rays which then pass by or through the cathodes as the X-rays exit the window in accordance with embodiments of the preset disclosure.
  • cathode array 102 maybe formed on the exit window itself.
  • Cathode array 102 may be an array of field emission cold cathodes.
  • Beam current 104 is emitted from cathode array 102 to impact anode target 106, disposed opposite or adjacent to exit window 110.
  • Anode target 106 may be a continuous sheet or slab of an X-ray target metal such as copper, tungsten or a tungsten-copper alloy. As shown in FIG. 2, anode target 106 may also be comprised of a film 302 of higher Z material, such as tungsten, attached to a sheet or slab 304 of material such as copper, chosen for lower cost, ease of working or superior heat dispersion characteristics. Film 302 may be bonded to sheet or slab 304 by sputtering or electroplating the material for film 302, by mechanically pressing film 302 on to sheet or slab 304 or by any other means which provides for the efficient conduction of heat from film 302 to sheet or slab 304.
  • Exit window 110 may therefore be chosen of a material compatible with vacuum sealing that has a low Z number. Table 1, which is presented in FIG. 3 A shows some of the available Exemplary Exit Window Choices. The values in the "X-pray Properties" columns were generated using the PENELOPE software code produced by Oak Ridge National Laboratories.
  • Various plastics may also be used for the exit window, provided that they have high mechanical strength and do not outgas to such an extent as to lower the vacuum inside the envelope and increase the risk of arcing or other vacuum breakdown. Plastics may be mechanically reinforced and passivated on the vacuum side with, for example, thin layers of oxides so as to increase their compatibility with vacuum operation.
  • Various forms of glass also have reasonably good X-ray transmission characteristics, are relatively inexpensive and are available in large sheets suitable for the formation of various types of wide cathode arrays. Sapphire is another viable choice for the exit windows.
  • cathode array 102 The absorption of X-ray flux by cathode array 102 can be minimized in two ways.
  • the cathode array can be made of thin-film field emission cold cathodes. As shown in Table 1, cathodes made of graphite or other forms of carbon, which can be made in thicknesses of under a micron, will absorb very little of the X-ray flux.
  • cathode array can be distributed over exit window 110 so as to occupy very little of the area of the exit window. An exemplary share of the cathode area to the total exit window area is under 10 percent.
  • FIG. 2 also shows a portion of side wall 308, an essential component of the vacuum envelope.
  • Side wall 308 is preferably made of an insulating material such as glass, alumina or other insulating ceramics such as MacorTM.
  • Side wall 308, exit window 110 and anode target 106 may be formed and joined in many different formats to provide radiation sources suitable for a variety of purposes. Cylindrical tubes of insulating material may be joined to circular exit windows and anode targets to form the vacuum envelope. Tubes of glass or ceramic are commonly available with diameters ranging from under two centimeters to over twenty centimeters.
  • the side walls may also be formed as rectangles by joining together strips of insulating material.
  • the distance between cathode array 102 on exit window 110 and anode target 106 may be set according to the electrical potential used between cathode and anode.
  • the distance should be sufficiently large to prevent arcing or other vacuum breakdown between cathode and anode at the chosen voltage. It should also be large enough to prevent external breakdown between conductive components such as feed throughs on the external side of the source.
  • An exemplary distance for a 100 keV potential is 2 - 5 centimeters.
  • the exit window may be provided in thicknesses of under one millimeter to several millimeters, while the anode target sheet or slab can be provided with a thickness of several centimeters.
  • the overall thickness of the source can thus be made from a few centimeters to perhaps ten centimeters.
  • the ratio of the width of the source to its thickness can therefore be made greater than 3: 1 and up to 100: 1, for an essentially flat radiation source.
  • Spacers 310 of suitable insulating material such as ceramics may be used to provide such support.
  • Internal walls may also be formed of glass or ceramic to provide such spacer support. In some embodiments of the disclosure, these internal walls can be arranged as a grid so as to allow the attachment of smaller exit windows in each grid opening, thereby creating a tiled exit window structure.
  • Side walls 308, exit window 110 and anode target 106 should be made and joined with materials having thermal coefficients of expansion (TCE) matched so as to prevent cracks in the vacuum envelope during X-ray production and consequent heat dissipation.
  • An exemplary set of materials is a tungsten-copper alloy for the anode target, alumina for the side walls and sapphire for the exit window.
  • the TCEs of these materials are very closely matched. They may be joined with frit glass sealing techniques common in the vacuum tube and flat panel display industries. Alternative sealing methods include O-ring seals of high- temperature materials such as VitonTM and mechanical clamping supports, vacuum-compatible epoxies or silica-based sealants.
  • Non-evaporable getters may be affixed inside the radiation source disclosed in this disclosure so as to maintain vacuum throughout the operational lifetime of the source. Electrical and getter activation feed throughs may be provided through sidewalls 308, exit window 110 or anode target 106. Anode target 106 may also have external electrical connection. Vacuum evacuation of the source may be accomplished through vacuum pumping through a pinch-off tube or valve attached to the source, or the assembly may be sealed in vacuum.
  • cold cathodes known in the art can be used in this disclosure, including metal or semiconductor tip arrays, flat cathodes of low-work-function materials, metal- insulator-metal cathodes, surface conduction emission cathodes, vertical or horizontal arrays of carbon nanotubes, or field emitters with conductive chunks embedded in an insulating medium.
  • a preferred cold cathode is the thin-film edge emitter.
  • field emission is from the external edges of a conductive thin film, which can be made of metal, various forms of carbon, or a carbon layer with upper and lower metal cladding layers to enhance conduction.
  • the cathodes can also be gated so as to provide greater current control than would be possible in diode operation and radiation source control at lower voltages.
  • Several gating schemes can be used. Separate transistors, such as field effect transistors, can be connected to individual cathodes or groups of cathodes.
  • One method employs an extraction gate placed close to the cathode. In this embodiment, a gate voltage between 20 and 2,000V can be used to extract current from thin-film edge emitter cathode, the current then being captured by the field established by a higher voltage between cathode and anode.
  • field emitters can sometimes emit debris due to micro discharges from the cathode or gate, or electromigration of material.
  • barriers to these material discharges so as to prevent cathode to gate shorts.
  • These barriers can be made of deposited material or etched into exit window 110.
  • Small pads for the cathodes and gates can also be made by depositing material or etching material from the window. These pads provide clearance for field lines between cathode and gate. They also allow the height of the gate to be raised in relation to the height of the cathode, which in turn provides control of the angle at which the electron beam current is emitted from the cathodes.
  • a resistor to improve emission uniformity across a cathode array, suppress emitter to extractor arcs, and to act as current limiters for any emitter to extractor shorts.
  • the line width, length and thickness can be varied to provide appropriate resistive values for cathodes operating under different conditions.
  • the operating principle is very simple, and is based on the doubling of a pulsed input voltage by laddered diode-capacitor stages.
  • the amplifier can be tapped at any stage to extract various voltages, as in a tapped transformer.
  • a CWA supplying 100 keV and 5mA, for example, may be made with twenty multiplier stages and a 3kV input to the first stage.
  • An external CWA or other step-up voltage amplifier may be used with the radiation source of this disclosure.
  • the CWA or other voltage amplification circuitry is disposed inside a vacuum envelope to take advantage of the superior insulation properties of vacuum.
  • arrays of small Kumakhov lenses may be formed as part of the exit window, or on a separate substrate placed in front of the exit window facing the X-ray target, or outside the window and attached to it.
  • Arrays of Kumakhov lenses or other X-ray focusing lenses may be made etching the substrates or by forming sacrificial pillars in the profile of the focusing optics around which the window or other substrate may be formed by melting or spin-on glass processes, with the pillars then etched away using chemical processes.
  • These lens arrays may be made as wide as an X-ray source made according to the disclosure, thereby providing wide sources of collimated X-rays.
  • FIG. 3 provides a diagram of an irradiation chamber in accordance with embodiments of the present disclosure.
  • Irradiation chamber 400 includes x-ray sources 402, outer side 406, irradiation chamber volume 410, support structure 416, anode surface 404, power supply 420, heat exchanger system 422 and shielding 424.
  • X-ray sources 402 include an anode surface 404 and cathode surface 408. In the embodiment shown in FIG. 3, two flat x- ray sources 402 as discussed above are arranged on either side of the irradiation chamber 400.
  • the power supply 420 is a standard power supply placed at the bottom of the irradiation chamber and supplies power to both the x-ray panels.
  • Heat exchanger system 422 is placed on the rear end with fans for cooling. The entire assembly is enclosed in shielding 424 such as a lead shield.
  • FIG. 5 shows a typical x-ray source in a point source geometry in accordance with embodiments of the present disclosure.
  • This arrangement 800 uses a cold cathode array 802, external grid 804, internal grid 806 and anode 810.
  • the shielding of the anode 810 by internal grid 806 allows the continuous anode to act as an array of point sources 812.
  • Emitter substrate and the tungsten anode 810 are assembled within a sealed vacuum envelop. Electrons 816 are emitted from the matrix addressed emitter array 802 according to the pixel being addressed. A high potential is applied between the emitter array and the anode 810. The pixilated electron beam 816 accelerates towards the anode 810, electron impact results in the production of X-rays 818 production. The x-rays 818 thus produced are pixilated or in other words the beam characteristics are defined by the electron source array. The X-ray beam is transmitted through the transparent cathode 802 and substrate 814 towards the object to be imaged or studied.
  • FIG. 6 shows a typical x-ray source 900 in a point source geometry having individual addressable emitters 902 in accordance with embodiments of the present disclosure.
  • X-ray source 900 includes individual addressable emitters 902, row and column addressing elements 904 and 906, anode 908 and substrate 910.
  • Individual addressable emitters 902 may be fabricated using microelectronic fabrication processes. In one instance, an emitter array may be fabricated on large flat panel glass substrate 910, the resolution of the photolithography tools sometimes limit the size of the individual emitters to large dimensions. Also, it is not always advantageous to fabricate devices on large substrates directly, as this limits operational performance of devices due to the poor high voltage stability of low temperature interlayer dielectrics.
  • high-density field emitter arrays may be fabricated on substrates of single crystal wafers such as silicon. This also allows one to build more robust devices with a variety of materials and dielectrics with a higher dielectric breakdown. Also, fabrication on silicon wafers allows one to fabricate devices with micron and submicron feature sizes, and emitters that can operate at voltages much less than 100V. This leads to increased emitter density to well beyond 10,000 emitters within a square millimeter area. This approach allows one to make devices on desired substrates and test the arrays and locate the arrays with optimum operating characteristics on a different substrate.
  • the underlying surface of the glass substrate is coated with a thin layer of a conductive film or conductive traces 1004 and 1006.
  • Desired materials for the conductive film include tungsten, tantalum, or any other material with high thermal and electrical conductivity.
  • the x-ray transmission through the film is a critical parameter and thickness of the film is limited to less than lOum.
  • FIGs. 8A and 8B show a typical x-ray source 1100 in a point source geometry having individual focusable emitters 1102 in accordance with embodiments of the present disclosure.
  • X-ray source 1100 includes individual emitters 1102, anode 1104, focusing electrode structures 1106 and 1108, and substrate 1114.
  • This approach may increase emission current density on the target/anode by using electron optics (focusing electrode structures 1106 and 1108) to focus emission from a large area on the cold cathode array into a small spot on the anode 1104. This is accomplished by placing suitable focusing electrode structures 1106 and 1108 having apertures 1110 and 1112 within the vacuum envelop between cold cathode array and the anode.
  • One of the important advantages of including an aperture array is to provide a conductive layer for bleed off charged particles that are generated during the electron impact process and by the impact of x-rays on various surfaces.
  • DAXS panels has several advantages in x-ray medical imaging.
  • the resulting systems are compact, provide higher temporal resolution, and allows for configurations that do not require the x-ray source to be moved.
  • a carousel within the irradiation chamber may be used to rotate the work piece within the irradiation chamber for uniform distribution of the electromagnetic flux to the work piece.
  • the work piece is supported within the irradiation chamber with a low attenuation support mechanism.
  • one or more flat electromagnetic sources positioned to irradiate an interior of the irradiation chamber are energized at a controlled energy level and time.
  • the electromagnetic (X-ray) sources have a number of addressable cathode emitters. The operation of the electromagnetic sources and the number of addressable cathode emitters is controlled by the process controller. Excess heat is removed from the one or more flat electromagnetic source with a heat transfer system in Block 1408.
  • the exterior is shielded from the electromagnetic flux within the irradiation chamber by a shielding system.
  • the electromagnetic flux comprising an X-ray flux or an ultraviolet flux.
  • a process controller may be used to coordinates the operation of the irradiation chamber; one or more flat electromagnetic sources, the heat transfer system; and the interlock system.
  • the present disclosure provides an apparatus and method for the X-ray irradiation of materials.
  • This apparatus includes an irradiation chamber, a number of flat electromagnetic (X-ray) sources having a number of addressable cathode emitters, a support mechanism, a heat transfer system, a shielding system, and a process controller.
  • a shielded portal within the shielding system allows access to an interior volume of the irradiation chamber.
  • the electromagnetic sources are positioned on or embedded within interior surfaces of the irradiation chamber. These electromagnetic sources generate an electromagnetic flux, such as an X-ray flux, where this flux is used to irradiate the interior volume of the irradiation chamber and any materials placed therein.
  • the operation of the electromagnetic sources and the number of addressable cathode emitters is controlled by the process controller.
  • the materials placed within the interior of the chamber may be supported by a low attenuation support mechanism. This low attenuation support mechanism does not substantially reduce the X-ray flux intended to irradiate the materials placed within the interior volume of the irradiation chamber.
  • the irradiation chamber may have a heat transfer system thermally coupled to the irradiation chamber and electromagnetic sources in order to remove heat from the interior surfaces of the irradiation chamber.
  • the shielding system external to the irradiation chamber prevents unwanted radiation from escaping from within the irradiation chamber.
  • inferred coupling includes direct and indirect coupling between two elements in the same manner as “operably coupled”.
  • the term "compares favorably”, as may be used herein indicates that a comparison between two or more elements, items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1.

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  • General Engineering & Computer Science (AREA)
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Abstract

L'invention concerne un appareil et un procédé pour l'irradiation de matières par rayons X. Cet appareil comprend une chambre d'irradiation, une pluralité de sources électromagnétiques (rayons X) plates comprenant une pluralité d'émetteurs cathodiques adressables, un mécanisme de support, un système de transfert de chaleur, un système de blindage et un dispositif de commande de processus. Un portail blindé dans le système de blindage permet d'accéder à un volume intérieur de la chambre d'irradiation. Les sources électromagnétiques sont disposées sur des surfaces intérieures de la chambre d'irradiation ou intégrées dans celles-ci. Ces sources électromagnétiques produisent un flux électromagnétique, tel qu'un flux de rayons X, ce flux étant utilisé pour irradier le volume intérieur de la chambre d'irradiation et toutes les matières placées dans celui-ci. La mise en oeuvre des sources électromagnétiques et des émetteurs cathodiques adressables est commandée par le dispositif de commande de processus. Les matières placées à l'intérieur de la chambre peuvent être supportées par un mécanisme de support à faible atténuation. Ce mécanisme de support à faible atténuation ne réduit pas sensiblement le flux de rayons X destiné à irradier les matières placées dans le volume intérieur de la chambre d'irradiation.
PCT/US2010/051580 2009-10-06 2010-10-06 Sources de rayons x en panneaux plats à adressage numérique WO2011044199A1 (fr)

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CN102299036A (zh) * 2011-07-18 2011-12-28 东南大学 基于场发射冷阴极的阵列x射线源
US8415628B1 (en) 2011-10-31 2013-04-09 General Electric Company Hermetically sealed radiation detector and methods for making
WO2018035171A1 (fr) * 2016-08-16 2018-02-22 Massachusetts Institute Of Technology Tomosynthèse à rayons x à l'échelle nanométrique pour une analyse rapide de puces de circuit intégré (ci)
US11145431B2 (en) 2016-08-16 2021-10-12 Massachusetts Institute Of Technology System and method for nanoscale X-ray imaging of biological specimen
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