CN101523543A - X-ray tube with ion deflecting and collecting device made from a getter material - Google Patents
X-ray tube with ion deflecting and collecting device made from a getter material Download PDFInfo
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- CN101523543A CN101523543A CNA2007800384029A CN200780038402A CN101523543A CN 101523543 A CN101523543 A CN 101523543A CN A2007800384029 A CNA2007800384029 A CN A2007800384029A CN 200780038402 A CN200780038402 A CN 200780038402A CN 101523543 A CN101523543 A CN 101523543A
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- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
- H01J35/20—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
- H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
- H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
- H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/20—Arrangements for controlling gases within the X-ray tube
- H01J2235/205—Gettering
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Abstract
The invention describes an X-ray tube (100) comprising an ion manipulation arrangement (140) having at least one ion collector electrode (141). The ion collector electrode (141) is made at least partially from a getter material. The ion manipulation arrangement (140) is in particular beneficial for high-end X-ray-tubes including an electrical field-free region (131). The ion manipulation arrangement (140) produces an electrical field, which deflects ions (150). When impinging onto the getter electrode (141) the ions (150) are permanently collected and thus removed from the interior of an evacuated envelope of the X-ray tube (100). This avoids ion bombardment on an electron emitter (111) of the X-ray tube (100). Additionally the arcing rate caused by residual gas can be reduced significantly. A heating of the getter material may be realized with heating wires or by a defined bombardment of scattered electrons (322) onto the electrodes (341, 342) comprising the getter material.
Description
Technical field
The present invention relates to produce the field of X ray by means of X-ray tube.Particularly, the present invention relates to a kind of X-ray tube that comprises the ion processing device, described ion processing device is suitable for collecting the residual particles in the vacuum (-tight) housing (evacuated envelope) that is present in X-ray tube.
The invention further relates to a kind of x-ray system, medical X-ray imaging system especially, wherein said x-ray system comprises aforesaid X-ray tube.
In addition, the present invention relates to a kind of method that is used to produce X ray, described X ray specifically is used for the medical X-ray imaging.This X ray produces by means of aforesaid X-ray tube.
Background technology
High-end and following X-ray tube needs variable focus shape, focus size and focal position can be provided.Compare with traditional X-ray tube, these pipes have distance greatly between the negative electrode of expression electron source and the target anode that produces focus on it.
Fig. 5 has schematically described this high-end X-ray tube 500.X-ray tube 500 comprises electron source 510, and it is suitable for producing the electron beam 515 that throws and end at target anode 520 along beam path.Discharge electronics from electronic emitter filament 511.With the X-ray tube contrast of standard, the distance between electron source and the target anode 520 is relatively large.
Between electron source 510 and target anode 520, be provided with field plate 530.Field plate 530 comprises opening 530a.Opening 530a allows electron beam 515 to pass described field plate 530.
Electron source is connected to high voltage source 512, and it (HV) comes respectively to electron source 510,511 power supplies of electronics emission filament with the negative high-voltage with respect to the shell of the X-ray tube of not describing 500.Target anode 520 and field plate 530 all are connected to ground voltage level.Therefore, can be divided into two zones respectively in the whole zone of extending between electron source 510 and the target anode 520: in the first area 531 of extending between electron source 510 and the field plate 530 and the second area 532 that between field plate 530 and target anode 520, extends.First area 531 comprises the electronics accelerating field.Second area 532 limits field-free or zero field regions.In field free region 532, be provided with electro optical element 536 to come focused beam 515 rightly by suitable electricity and/or magnetic multipole field.In order to realize best focus characteristics, electronic emitter 511 must be placed on the optical axis of electron-optical system 536.
The electronics that is discharged is accelerated towards target anode 520 from electron source 510.Thus, they pass opening 530a and enter the field free region 532 that they are focused.When focus 521 is hit target anode 520, initial (primary) electronics near 40% is reversed scattering and advances along straight line 522 in field free region 532.The energy accumulation of the described electronics that is scattered is in the water-cooled sidewall of not describing.
Because in the pipe is not to be desirable vacuum, so the atom of residual gas and molecule may be ionized.This ionizing particle can be subjected to the influence of the electromagnetism and the electrostatic lens of high voltage and/or optical system.In these ions some are quickened towards electronic emitter.Optical system can focus on these ions, and these ions strike on the surface of reflector with point subsequently.The instant fault that this can damage emitter structures and reduce useful life thus or cause emitter structures.Particularly, this situation is more obvious for the X-ray tube with high voltage acceleration region and back to back no electric field region.
US 4,521, and 900 disclose the electron beam assembly that is used for scanning beam calculating computed tomography scanning instrument.Electron beam produce and control assembly at its electron beam of the indoor generation of vacuum-packed shell, wherein there is small portion of residual gas inevitably in the described shell chamber internal gas of finding time.Generate electron beam by this indoor appropriate device.Because at this indoor residual gas that exists, so the electronics of this electron beam will and produce cation thus with its interaction, during it produces and the effect of the space charge of electron beam.In order to reduce the neutralizing effect of these ions, be provided with ion and remove electrode.These electrodes are configured to generate the uniform electric field of the axle that is orthogonal to electron beam.These electrodes and potential well lateral alignment are so that remove cation from the zone of electron beam.
US 2003/0021377 discloses mobile x-ray source, comprises low consumption cathode element and anode optical element, and this anode optical element is used to create field free region to prolong the life-span of cathode element.Electric field is applied to anode and negative electrode, and described anode and negative electrode are arranged on the opposite side of vacuum tube.Anode comprises the target material that produces X ray in response to electronic impact.Negative electrode comprises the cathode element that produces electronics, described electronic response between described anode and negative electrode electric field and by being quickened towards anode.Field free region can be positioned at anode and quicken to resist cation towards cathode element conversely.Anode tube can be arranged on the anode between anode and the negative electrode, and is electrically coupled to described anode, makes described anode and anode tube have same potential, to form field free region.Gettering material is arranged in the vacuum tube so that remove residual gas in the pipe after vacuum seal.Getter can be arranged in the field free region of pipe.
US 5,509, and 045 discloses a kind of X-ray tube.This X-ray tube comprises vacuum (-tight) housing, wherein is provided with anode, negative electrode and air-breathing radome.With respect to anode, described air-breathing shielding cover is put in the negative electrode back.Air-breathing radome comprises sheath and cap body.Described cap body limits cannelure.Gettering material is deposited in the groove and is sintered to limit a porous body.Be activated in the gettering material X-ray tube normal exhaust process during manufacture.In X-ray tube operating period, waste heat is used for gettering material is risen to its pumping temperature by the cap bulk absorption.
Need provide a kind of X-ray tube at this, it can remove residual atom and molecule effectively.
Summary of the invention
Can satisfy this needs by theme according to independent claims.By dependent claims useful embodiment of the present invention is described.
According to a first aspect of the present invention, a kind of X-ray tube is provided, comprise (a) electron source, it is suitable for producing the electron beam along the beam path projection, (b) target anode, it is arranged in the described beam path and is suitable for producing the X-ray beam that derives from described electron beam focus, and (c) ion processing device, and it is suitable for deflection and collects the ion that is produced by the collision of atom that exists in electron beam and beam path that scattered electron wherein occurs or the space and molecule.The ion processing device comprises collector electrode, and it is chargeable, is made by gettering material so that provide for the electrostatic attraction of at least some ions and its to small part.
Of the present invention this is based on the thought that the ion processing device can have the seedbed to attract ion and absorb ion on the one hand.Its effect is and can removes effectively at the inner ion that produces of the vacuum (-tight) housing of described X-ray tube the most of zone in X-ray tube.With only comprise common electrode and only by to or from ion, add or remove at least one electronics ion is converted to the ion processing device contrast of corresponding atom or molecule, described ion processing device can for good and all be removed ion and corresponding atom or molecule from the vacuum chamber of X-ray tube.
Hold in the vacuum (-tight) housing that after vacuumizing, is permanently sealed under the situation of X-ray tube, for good and all remove ion and help in long-time, the residual pressure in the shell to be maintained reduced levels.
In addition, for good and all remove residual ion and reduced arcing rate.If ion enters the high-voltage region of X-ray tube, arc discharge may take place.
In addition, for good and all remove residual ion has reduced influences electro optical element in indeterminate mode space charge compensation.
In addition, for good and all remove the ion bombardment unintentionally of electronic emitter filament that residual ion has reduced the ion bombardment unintentionally, particularly electron source of electron source.If positive charge ion is attracted by the negative electrical charge electron source and strikes on the electronic emitter filament, this bombardment may take place.Because the electronic emitter filament generally is mechanically highstrung element,, thereby can shorten useful life of X-ray tube significantly so this ion bombardment may cause the accelerated deterioration of electron source.
Described X-ray tube can be understood that improved asepwirator pump.In this respect, the electron beam that is used to produce X ray also is used for atom and the molecule that ionization exists in the vacuum chamber of X-ray tube.This means that electron beam is used as the ionization device of residual atom and molecule.Because this ionisation effect can attract atom and molecule from the relative broad space zone in the vacuum chamber.In contrast, the suction device that uses in known X-ray tube only can just absorb described ion, atom and molecule respectively when ion, atom and molecule strike on the gettering material once in a while.Therefore, compare, improved the collection efficiency of described collector electrode significantly with the known suction device that is used for X-ray tube.
Preferably, gettering material is the metal such as titanium and/or aluminum-zirconium alloy.Therefore, when ion touched gettering material, they were neutralized and can be collected the device electrode immediately and for good and all absorb.Thus, can easily realize from the vacuum chamber of X-ray tube, removing fully.
Atom and molecule generally are the atom and the molecules of residual gas that is positioned at the vacuum chamber of described X-ray tube.Residual gas for example is carbon monoxide, nitrogen, oxygen, water, metal vapors and/or particularly hydrocarbon.
According to the embodiment of the invention, the ion processing device comprises other electrode.This provides the advantage that can set up the electric field of accurate qualification between collector electrode and other electrode.Thus, can with spatially reliably mode limit attracted the deflection path of ion, described deflection path terminates at collector electrode.This means in the interaction zone of ion processing device, particularly, provided predetermined ion deflection path by each the possible ion position in the zone that spatial placement limited of collector electrode and other electrode.
Must mention that in this ion processing device can also have plural electrode.Usually, the ion processing device can comprise any multipole layout of electrode, and described layout is suitable for the charged particle of the interaction zone that is arranged in the ion processing device is produced attraction.
According to further embodiment of the present invention, collector electrode is in negative voltage level with respect to ground voltage and other electrode is in positive voltage level with respect to ground voltage.Such advantage is that two electrodes all produce power to the charged particle of the interaction zone that is arranged in the ion processing device.Thus, two power are come acting in conjunction with mutual support pattern.For example for negatively charged ions, collector electrode applies attraction and other electrode applies repulsive force to negatively charged ions to this ion.
Must mention that in order to produce described dipole field, two electrodes must be connected to the supply voltage different with ground voltage.This means that described X-ray tube must have two isolation elements so that with the electric mutually isolation of the shell of two electrodes and X-ray tube.Mention further that in this respect the target anode also can be in ground level, and electron source must be in negative high-voltage level so that essential electron accelerating voltage is provided.
According to further embodiment of the present invention, X-ray tube further comprises field plate, and it is disposed between electron source and the target anode.Thus, limit (a) in the first area of extending between electron source and the field plate and the second area that between field plate and target anode, extends.Field plate is suitable for being in the voltage level substantially the same with the target anode.
Must mention that in this respect field plate comprises at least one little opening, so that the ground that electron beam can not be attenuated penetrates described field plate.
In described X-ray tube design, the first area comprises the necessary electric field of electronics that acceleration discharges from electronic emitter.The electronics that is quickened leaves the first area by opening and enters the second area that limits field-free region.Wherein, described electronics can be towards the target anode with straightaway.
Provide the advantage of field-free second area to be: can the arranging electronic beam processing apparatus in second area, such as electron beam focusing optical element and/or electron beam deflecting unit.These equipment can make electricity consumption and/or magnetic field be used for separately electron beam treatment.Bundle focusing optical element can be used for electron beam is pointed to focus on the target anode surface, and but but described whereby focus has predetermined variable shape and predetermined variable size.Electron beam deflecting unit can be used for controlling the position of focus.For example, focus can change between at least two predetermined focal positions discretely, thereby realizes multifocal X-ray tube.
According to the further embodiment of the present invention, the ion processing device is arranged in second area.Such advantage is that above-mentioned ion processing can carry out under the situation that not influenced by the electronics accelerating field.Therefore, compare with accelerating voltage, less relatively voltage just enough is used for the interior ion of vacuum (-tight) housing that deflection reliably and collection are present in the X-ray tube of describing.
According to the further embodiment of the present invention, the ion processing device is orientated as near electron beam.
In this respect, term " approaching " means at the electric field of the ion processing device of ionization position enough strong, so that the ion that is generated attracted to an electrode of ion processing device.Particularly, this ionization position is positioned at electron beam.This means that the ion attraction is suitable for the heat fluctuation of overcompensation ion, described heat fluctuation is generally measured with absolute temperature.
Term " approaching " also means other element of not arranging X-ray tube between ion processing device and beam path.
Be positioned at the ion processing device under the situation of field-free basically second area, the electric field that is produced by the ion processing device must be better than the stray magnetic field of electronics accelerating field, and described stray magnetic field by mistake enters field-free second area.
If the ion processing device comprises two electrodes, so preferred these electrodes directly be arranged in electron beam around.In addition, collector electrode and other electrode can be orientated as near optical electron bundle concentrating element.This means can be with ion from locally directly removing that their produce, promptly near the electron beam and have a zone of scattered electron.Such advantage is that ion will can not enter the critical high voltage first area of X-ray tube, thereby can reduce arcing rate significantly.
According to further embodiment of the present invention, X-ray tube is suitable for controlling the temperature of gettering material.
In this respect, term " control " must be understood with wide in range implication.Control outside the temperature divided by the mode that is limited, any means of the temperature of gettering material also represented to be suitable for influencing, revising and/or handle in term " control ".Such advantage is to remain in the predetermined temperature limitation by the temperature with collector electrode, can improve the efficient of employed gettering material.
According to further embodiment of the present invention, gettering material is heated.The Optimal Temperature scope that is generally used for improving the ion trap ability of gettering material is higher than the mean temperature in the X-ray tube that generally is present in the use.Therefore, by difference heated getter material and ion trap electrode, can improve the efficient of aspiration electrode significantly.
According to further embodiment of the present invention, X-ray tube further comprises the heater control unit, and it is suitable for having seedbed heated getter material.Thus, for example, can realize active heating by means of on the gettering material and/or the heating wires of in gettering material, installing.
Described active heating can be carried out point-device temperature control to aspiration electrode.By using suitable temperature sensor, temperature control can be embodied as open loop or closed loop.
According to further embodiment of the present invention, X-ray tube is designed to not have seedbed heated getter material.Thus,, particularly derive from the waste heat of target anode, can realize not having the temperature that gettering material and ion trap electrode are improved in the seedbed respectively by the waste heat of X-ray tube.
The advantage of the passive heating of described gettering material is and needn't provides extra electrical connection just can realize that temperature raises to the ion trap electrode that described extra electrical connection is used for being installed in the heating wires power supply on the gettering material and/or in gettering material.Therefore, connect by avoiding further cable, the overall structure of described X-ray tube is simple relatively, thereby can keep the manufacturing cost of described X-ray tube relatively low.
According to further embodiment of the present invention, X-ray tube is designed to come the heated getter material by means of the scattered electron that mainly comes from the focus on the target anode.Thus, in the lip-deep focus of target anode, produce scattered electron, and if the target anode be arranged in field-free basically second area, scattered electron is basically along straightaway so.When hitting gettering material and ion trap electrode surperficial respectively, electronics discharges their energy in block materials.In the operating period of X-ray tube, this causes heating automatically the ion trap electrode.
The height that temperature raises depends on the thermal contact of any cooling surface of ion trap electrode and X-ray tube.Therefore, the little thermal contact of design will cause relatively large temperature to raise intentionally.In other words, by suitable thermal conductivity is provided, can select the proper temperature scope of ion collection electrode between ion trap electrode and cooling surface.
Come the advantage of passive heating ion collection electrode to be that the heating of gettering material when X-ray tube enters operation begins immediately by means of scattered electron.
According to further embodiment of the present invention, X-ray tube further comprises shielding element, and its predetermined portions that covers collector electrode at least is to avoid being scattered electrons hit.Such advantage is to protect respectively ion trap electrode and gettering material to avoid overheated, makes temperature can not surpass temperature upper limit.More than this temperature upper limit, will reduce the ionic absorption efficient of gettering material.
Can realize the shielding of ion trap by means of simple projection, it provides the screen effect to scattered electron.Projection can be formed in the cast parts of electron beam path.
Must mention, can also design shielding element in the mode of the particle radiation amount that reduces scattered electron.In other words, shielding element can not absorb and/or reflect the electronics that points to a part of collector electrode fully; Described shielding element only reduces the amount of radiation that acts on collector electrode.Such advantage is can avoid effectively because damage that electron bombard on a large scale caused or acceleration are degenerated for all parts of ion trap electrode.
According to further embodiment of the present invention, X-ray tube is designed to come the heated getter material by means of thermal radiation and/or by means of heat conduction, and this heat conduction derives from the target anode and ends at aspiration electrode.
Thus in particular, thermal radiation and heat conduction can come from the target anode respectively, described target anode general proxy the thermal element in the X-ray tube of describing.Yet other thermal source also can be used for coming the heated getter material by means of thermal radiation and/or heat conduction.Point out that as top such heating that is also advantageous in that gettering material when X-ray tube is operated will begin automatically.
According to further embodiment of the present invention, X-ray tube further comprises attenuating elements, and described attenuating elements protects the predetermined portions of collector electrode to avoid by irradiated with thermal radiation and/or to avoid heating by means of heat conduction at least.
Provide attenuating elements can also prevent that collector electrode is overheated, make temperature can not surpass temperature upper limit.Therefore, attenuating elements can be arranged in any suitable position in the described X-ray tube.
According to another aspect of the present invention, provide a kind of x-ray system, particularly as the medical X-ray imaging system of computed tomography system.The x-ray system that is provided comprises according to any one X-ray tube in the foregoing description.
Of the present inventionly be based on following thought in this respect:, can use above-mentioned X-ray tube according to useful mode for various x-ray systems, particularly for the x-ray system that is used for medical diagnosis.
Must mention that described x-ray system can also be used for other purpose except that medical imaging.For example, described x-ray system can also be used for for example safety system of baggage inspection apparatus.
According to further aspect of the present invention, a kind of X ray that is used to produce is provided, particularly produce the method for the X ray that is used for the picture calculating computed tomography.The method that is provided comprises that use is according to any one X-ray tube in the foregoing description of X-ray tube.
Embodiments of the invention have been should be noted that with reference to different subject descriptions.Particularly, reference device type claim has been described some embodiment, and reference method type claim has been described other embodiment.Yet, those skilled in the art will understand unless otherwise indicated according to above and following description, otherwise belong to any characteristics combination of a class theme and any combination between the feature relevant with different themes, particularly any combination between the feature of the feature of device type claim and Method type claim also is considered to disclosed by the application.
According to exemplary embodiment described below, above-mentioned aspect of the present invention and further aspect will become clearer, and the example of reference example makes an explanation.Example below with reference to embodiment is described the present invention in more detail, but the present invention is not so limited.
Description of drawings
Fig. 1 shows the sectional view of X-ray tube, and described X-ray tube is equipped with the ion processing device that comprises two electrodes, and wherein said electrode transversely is arranged on the electron beam path.
Fig. 2 a shows the sectional view perpendicular to the electron beam axis of ion processing device depicted in figure 1.
Fig. 2 b shows the sectional view of ion processing device depicted in figure 1, has wherein indicated the some Ion paths towards the ion trap electrode.
Fig. 3 a shows the sectional view of ion processing device, and described ion processing device origin comes from the scattered electron heating of the focus on the target anode.
Fig. 3 b shows the sectional view of ion processing device, and described ion processing device partly avoids receiving the bombardment of scattered electron by projection.
Fig. 4 shows the rough schematic view of calculating computed tomography (CT) system according to the embodiment of the invention, and wherein the CT system disposition has the multi electron beam X-ray tube.
Fig. 5 shows the schematic diagram of prior art X-ray tube, is included in the relatively large distance between electron source and the target anode and wherein is furnished with the field free region of electro optical element.
Embodiment
Explanation in the accompanying drawing is schematic.Should be noted that in different accompanying drawings similar or same element has identical Reference numeral or compares with corresponding Reference numeral is the different Reference numeral of first bit digital.
Fig. 1 shows the sectional view of X-ray tube 100.X-ray tube 100 comprises the electron source 110 with electronic emitter 111.When heating, electronic emitter 111 can discharge along the electronics of beam path 115 projections.For clarity sake, in Fig. 1, do not express the beam optics element of similar Wehnelt cylinder (Wehneltcylinder).
Must mention, can utilize dissimilar target anodes to realize the present invention.Particularly, target anode 120 can be rotatable anode or fixed anode.
The electronics that is discharged is accelerated to target anode 120 from the electron source 110 of expression negative electrode.Thus, they pass opening 130a and enter field free region 132.In the time of on striking target anode 120, they produce the X-ray beam that derives from focus 121.
Because in the pipe is not desirable vacuum, so the atom of residual gas and molecule can be by electron beam 115 and the scattered electron ionization of reflecting from focus 121.Thereby produce ion 150.
Overheated for some parts that compensates X-ray tube, water-cooled sidewall 135 is provided.According to embodiment as described herein, water-cooled sidewall 135 is integrally formed with field plate 130.
Described X-ray tube 100 is equipped with ion processing device 140.Ion processing device 140 comprises two electrodes: ion trap electrode 141 and other electrode 142.Electrode 141,142 is directly arranged by electron beam path 115.Here, term " directly " means between each and the electron beam path 115 in electrode 141,142 and does not have other any element.
With respect to the shell of not describing that is in ground voltage level, ion trap electrode 141 is connected to negative voltage-V.Other electrode 142 is connected to positive voltage+V with respect to ground level.Thus, produce the eelctric dipole field between two electrodes 141,142, this electric field is attracted to ion trap electrode 141 with cation 150.Corresponding Ion paths is represented with Reference numeral 152.
Must mention that in the first of Ion paths 152, ion 150 can be attracted by the residual electricity place of extending between electron source 110 and the target anode 120.Yet when near the interaction zone of ion processing device 140, ion 150 will suffer the eelctric dipole field that produced by two electrodes 141,142.The polarity that depends on ion 150, this makes ion towards one of electrode 141,142 deflection.
Must mention that ion processing device 140 also can comprise plural electrode or passive electrode only.For example, ion processing device 140 can be one pole, four utmost points, five utmost points, sextupole or the ends of the earth.Usually, the ion processing device can comprise any multipole layout of electrode, and described multipole layout is suitable for producing the attraction to the charged particle in the interaction zone that is in ion processing device 140.
Two electrodes 141,142 are made by gettering material, and described gettering material can for good and all absorb described ion 150 when ion 150 touches each self-electrode.Gettering material is the metal such as titanium and/or aluminum-zirconium alloy.Therefore, when ion 150 contact gettering materials, they are neutralized immediately.This makes the permanent ion 150 that absorbs be more prone to.For good and all removing ion 150 helps to keep low-residual pressure and reaches the long period in casing.Thereby, also reduced by atom that enters first electron acceleration region 131 and the caused residual arc discharge rate of molecule.
As can be seen from Figure 1, ion trap electrode 141 is electrically coupled to heater control unit 145.Other electrode 142 is provided with equally.Yet, for the purpose of drawings clear, in Fig. 1, omitted corresponding cable.Heater control unit 145 can be with the thermal wire power supply of thermocurrent for not describing.Thermocurrent can be AC or DC electric current.
Thermal wire is installed in the electrode 141,142 or on electrode 141,142, thereby allows the gettering material of two electrodes to be heated.By heating electrode, can distinguish the gettering efficiency and the air-breathing rate that improve gettering material significantly.By there being seedbed control to offer the thermocurrent of two electrodes 141,142, can avoid the harmful overheated of gettering material.
In contrast, but known X-ray tube also comprises no electric field region does not comprise described ion processing device 140, thereby has the risk that makes the emitter structures accelerated deterioration.This deterioration can be caused by the ion that produces in no electric field region, for example the ion that collision produced by residual atom and molecule and electron beam.In these ions some are quickened towards electronic emitter.The electron-optical system that is arranged in the no electric field region can focus on these ions, and described ion strikes on the surface of reflector with point subsequently.This can damage emitter structures and reduce useful life thus or cause instant fault.
Must mention, in not having the standard X-ray pipe of electric field region, also the ion bombardment of described electron source may not occur and bring out deterioration.Yet this situation is especially obvious for the high-end X-ray tube with high voltage acceleration region and back to back no electric field region.
Here, described ion processing device 140 can be interpreted as preventing that ion 150 from entering the reliable barrier of high voltage acceleration region 131.
Described X-ray tube be applicable to wherein must avoid ion bombardment to the electronic emitter to keep any field of X-ray tube steady operation.In addition, described X-ray tube is applicable to the arcing rate that reduces by ion brought out in electron-beam tube.
Fig. 2 a shows the sectional view perpendicular to the electron beam axis of ion processing device 140 depicted in figure 1, and described ion processing device indicates with Reference numeral 240 now.The field plate 230 that is connected to level electrical ground in a tubular form.In the middle of field plate 230, be furnished with ion trap electrode 241 and other electrode 242.Electrode 241,242 all comprises arc.Ion trap electrode 241 is connected to negative voltage-V.Other electrode 242 is connected to positive voltage+V.Electrical insulation parts 243 is provided for is respectively realizing that electricity separates between the field plate 230 of ground connection and the ion trap electrode 241 and between the field plate 230 of ground connection and other electrode 242.
Fig. 2 b shows the sectional view of ion processing device 240.The eelctric dipole field of extending between two electrodes 241 and 242 causes acting on the electrostatic force of ion 250, and described ion is by electron beam of not describing and the scattered electron generation do not described.Some Ion paths 252 have also been indicated among the figure towards ion trap electrode 241.
Fig. 3 a shows the sectional view of the ion processing device 340 of the further embodiment according to the present invention.According to the foregoing description, ion processing device 340 also is disposed in the tubular field electrode 330, and described tubular field electrode 330 has been represented water-cooled sidewall 335.Ion processing device 340 comprises two electrodes: collector electrode 341 and other electrode 342, both are made by gettering material at least in part.
With the foregoing description contrast, gettering material is not had the seedbed heating.On the contrary, gettering material heats with passive mode.Particularly, electrode 341 and 342 is heated by the particle radiation that comprises electronics.According to embodiment as described herein, these electronics are produced by back scattered electron, described back scattered electron produce at the focus place on the target anode and described back scattered electron in no electric field region along straightaway.These scattered electrons are represented with arrow 322.When hitting the surface, electronics discharges their energy in the block materials of electrode 341,342.
Must mention that electrode 341,342 can also heat by thermal radiation and/or heat conduction between target anode and electrode 341,342.
Surpass temperature extremes and reduced the air-breathing rate of ion, described temperature extremes depends on employed gettering material.Therefore, it is useful avoiding overheated.
Fig. 3 b shows the exergonic principle possibility of ion processing device 340 restrictions for fixed geometry.Shielding element 337 coated electrodes 341 and 342 qualifying part, and reduced the number of electrons that strikes on electronics 341 and 342 thus.Therefore, with respect to the embodiment shown in Fig. 3 a, electrode 341 and 342 maximum temperature have reduced.
According to embodiment as described herein, shielding element is the simple protrusion that forms on tubular field electrode 330.Yet the shielding element that obviously can also use other type is to realize reducing the constructed effect of scattered electron and/or caloradiance.
Must mention that owing to do not reach maximum temperature before finishing applying load, the passive heating by scattered electron 322 utilizes the active heating of heating wires to compare so inaccurate with above-mentioned.Yet, being used to realize that the effort of heating is much smaller for passive alternative, passive alternative also can realize by thermal radiation and/or heat conduction.
Fig. 4 shows calculating computed tomography (CT) equipment 470, and it is also referred to as CT scanner.CT scanner 470 comprises frame 471, and they can be around rotating shaft 472 rotations.Described frame 471 drives by means of motor 473.
The radiation source of Reference numeral 475 expression such as X-ray tubes, described radiation source emission multiple spectra radiation 477.X-ray tube 475 is the X-ray tubes corresponding to any the foregoing description.
During scanning area-of-interest 480a, x-ray source 485, aperture system 476 and detector 485 rotate with frame 471 on by the direction of rotation of arrow 487 expressions.For rotary frame 471, motor 473 is connected to motor control unit 490, itself is connected to data processing equipment 495.Data processing equipment 495 comprises reconfiguration unit, and it can be realized by means of hardware and/or software.Reconfiguration unit is suitable for coming the reconstruct 3D rendering according to a plurality of 2D images that obtain under each viewing angle.
In addition, data processing equipment 495 is also as control unit, and it is communicated by letter so that the motion of the motion of frame 471 and operating desk 482 is coordinated mutually with motor control unit 490.The line shifting of operating desk 482 is carried out by motor 483, and it also is connected to motor control unit 490.
In 470 operating periods of CT scanner, frame 471 rotations and simultaneously operating desk 482 be parallel to rotating shaft 472 straight lines and move, thereby carry out helical scanning to area-of-interest 480a.Should be noted that and to carry out circular scanning wherein on the direction parallel, do not have displacement, and just come rotary frame 471 around rotating shaft 472 with rotating shaft 472.Thus, can measure head 480a section accurately.By after at least one half frame rotation of operating desk position executed discrete for each, with rotating shaft 472 abreast with discrete step sequence ground move operation platform 482, can obtain the bigger three dimensional representation of patient's head.
For the 3D of the reconstruct of observing patient's head 480a represents that display 496 is provided, and described display 496 is coupled to data processing equipment 495.In addition, can also print any section that 3D represents perspective view by printer 497, described printer 497 also is coupled to data processing equipment 495.In addition, data processing equipment 495 also can be coupled to PACS 498 (PACS).
Should be noted that the monitor 496, printer 497 and/or the miscellaneous equipment that are provided in the CT scanner 470 can be arranged in the computed tomography apparatus 470 this locality.Perhaps, these assemblies can be away from CT scanner 470, such as other place in research institute or hospital, or diverse position, this position is linked to CT scanner 470 via the one or more configurable network such as the Internet, VPN (virtual private network) etc.
Should be noted that term " comprises " that not getting rid of other element or step and " one " or " a kind of " does not get rid of a plurality of situations.Can also make up the element that is associated and describes with different embodiment.Shall also be noted that Reference numeral in the claim should not be interpreted as the restriction to the claim scope.
In order to summarize the above embodiment of the present invention, can state:
Described a kind of X-ray tube 100 that comprises ion processing device 140, described ion processing device 140 has at least one ion trap electrode 141.Described ion trap electrode 141 to small part is made by gettering material.Described ion processing device 140 is particularly useful for the high-end X-ray tube that comprises no electric field region 131.Described ion processing device 140 produces the electric field of deflect ions 150.In the time of on striking aspiration electrode 141, ion 150 is for good and all collected and is therefore removed from the vacuum (-tight) housing of described X-ray tube 100 is inner.This has been avoided ion bombardment to the electronic emitter 111 of X-ray tube 100.In addition, can reduce the arcing rate that causes by residual gas significantly.The heating of gettering material can utilize heating wires to realize, or comprises by 322 pairs of scattered electrons that the qualification of the electrode 341,342 of gettering material is bombarded and realize.
The tabulation of Reference numeral:
100 X-ray tubes
110 electron sources
111 electronic emitter filaments
112 high voltage sourcies
115 electron beams/beam path
120 target anodes
121 focuses
125 X-ray beams
130 field plates
The 130a opening
131 first areas/electron acceleration region
132 second areas/field free region
135 water-cooled sidewalls
140 ion processing devices
141 collector electrodes
142 other electrodes
145 heater control units
150 ions
152 Ion paths to ion trap electrode 141
230 field plates
240 ion processing devices
241 collector electrodes
242 other electrodes
243 electrical insulation parts
250 ions
252 Ion paths to collector electrode 241
322 scattered electrons
335 water-cooled sidewalls
337 shielding elements/projection
330 field plates
340 ion processing devices
341 collector electrodes
342 other electrodes
470 medical X-ray imaging system/computed tomography apparatus
471 frames
472 rotating shafts
473 motors
475 x-ray sources/X-ray tube
476 aperture system
477 radiation beams
480 interested object/patients
480a area-of-interest/patient's head
482 operating desks
483 motors
485 X-ray detectors
The 485a detector element
487 direction of rotation
488 pulse discriminator unit
490 motor control units, 495 data processing equipments (comprising reconfiguration unit)
496 monitors
497 printers
498 PACSs (PACS)
500 X-ray tubes
510 electron sources
511 electronic emitter filaments
512 high voltage sourcies
515 electron beams/beam path
520 target anodes
521 focuses
522 scattered electrons
530 field plates
The 530a opening
531 first areas/electron acceleration region
532 second areas/field free region
536 electro optical elements
Claims (16)
1, a kind of X-ray tube comprises:
Electron source (110), it is suitable for producing the electron beam (115) along the beam path projection,
Target anode (120), it is arranged in the described beam path (115) and is suitable for producing the X-ray beam (125) of the focus (121) that derives from described electron beam (115), and
Ion processing device (140), it is suitable for deflection and is suitable for collecting the ion (150) that is produced with the collision of interior atom that exists of described beam path and molecule by described electron beam or scattered electron (115), wherein said ion processing device (140) comprises collector electrode (141)
-described collector electrode (141) is chargeable, so as to provide for the attraction of at least some described ions (150) and
-described collector electrode (141) to small part is made by gettering material.
2, X-ray tube as claimed in claim 1, wherein
Described ion processing device (140) comprises other electrode (142).
3, X-ray tube as claimed in claim 1, wherein
Described collector electrode is in negative voltage level with respect to ground voltage, and
Described other electrode (142) is in positive voltage level with respect to ground voltage.
4, X-ray tube as claimed in claim 1 also comprises
Field plate (130,230,330), it is arranged between described electron source (110) and the described target anode (120), thereby limits:
The first area (131) of-extension between described electron source (110) and described field plate (130), and
The second area (132) of-extension between described field plate (130) and described target anode (120),
Described thus field plate (130) is suitable for being in and the substantially the same voltage level of described target anode (120).
5, X-ray tube as claimed in claim 4, wherein
Described ion processing device (140) is arranged in the described second area (132).
6, X-ray tube as claimed in claim 1, wherein
Described ion processing device (140) is set near described electron beam (115).
7, X-ray tube as claimed in claim 1, wherein
Described X-ray tube (100) is suitable for controlling the temperature of described gettering material (141,142,341,342).
8, X-ray tube as claimed in claim 7, wherein
Described gettering material (141,142,341,342) is heated.
9, X-ray tube as claimed in claim 8 also comprises
Heater control unit (145), it is suitable for having the seedbed to heat described gettering material (141).
10, X-ray tube as claimed in claim 8, wherein
Described X-ray tube is designed to not have the seedbed and heats described gettering material (341,342).
11, X-ray tube as claimed in claim 10, wherein
Described X-ray tube is designed to heat described gettering material (341,342) by means of the scattered electron (322) that is mainly derived from the described focus on the described target anode.
12, X-ray tube as claimed in claim 11 also comprises
Shielding element (337), its predetermined portions that covers described collector electrode (341) are at least hit by described scattered electron (322) avoiding.
13, X-ray tube as claimed in claim 10, wherein
Described X-ray tube is designed to heat described gettering material by means of thermal radiation between described target anode and aspiration electrode and/or heat conduction.
14, X-ray tube as claimed in claim 13 also comprises
Attenuating elements, its predetermined portions of protecting described collector electrode at least is to avoid by described irradiated with thermal radiation and/or to avoid being heated by means of heat conduction.
15, a kind of x-ray system, particularly as the medical X-ray imaging system of computed tomography system (470), described x-ray system comprises:
X-ray tube as claimed in claim 1 (100).
16, a kind ofly be used to produce X ray, particularly produce the method for the X ray of the medical X-ray imaging that is used for the picture computed tomography, described method comprises:
Use X-ray tube as claimed in claim 1 (100).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP06122319 | 2006-10-16 | ||
| EP06122319.4 | 2006-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101523543A true CN101523543A (en) | 2009-09-02 |
Family
ID=39231810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007800384029A Pending CN101523543A (en) | 2006-10-16 | 2007-10-10 | X-ray tube with ion deflecting and collecting device made from a getter material |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP2082411A2 (en) |
| JP (1) | JP2010507188A (en) |
| CN (1) | CN101523543A (en) |
| WO (1) | WO2008047267A2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102456527A (en) * | 2010-10-26 | 2012-05-16 | 通用电气公司 | Apparatus and method for improved transient response in an electromagnetically controlled X-ray tube |
| CN102842477A (en) * | 2012-09-20 | 2012-12-26 | 苏州生物医学工程技术研究所 | X-ray tube |
| CN104541332A (en) * | 2012-06-14 | 2015-04-22 | 伊克斯拉姆公司 | Limiting migration of target material |
| CN104616952A (en) * | 2012-12-31 | 2015-05-13 | 同方威视技术股份有限公司 | Cathode-control multi-cathode distributed X-ray device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6244897B2 (en) * | 2013-12-26 | 2017-12-13 | 株式会社島津製作所 | X-ray analyzer |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3309523A (en) * | 1963-06-24 | 1967-03-14 | Field Emission Corp | X-ray tube having field emission cathode and evaporative anode in combination with electrical pulser means |
| JPS5590039A (en) * | 1978-12-28 | 1980-07-08 | Jeol Ltd | X-ray generator |
| US6044129A (en) * | 1997-11-21 | 2000-03-28 | Picker International, Inc. | Gas overload and metalization prevention for x-ray tubes |
| JP4409120B2 (en) * | 2001-06-29 | 2010-02-03 | 株式会社東芝 | Rotating anode X-ray tube |
| JP2004146158A (en) * | 2002-10-23 | 2004-05-20 | Shigekimi Kita | Field emission type x-ray source |
-
2007
- 2007-10-10 WO PCT/IB2007/054121 patent/WO2008047267A2/en active Application Filing
- 2007-10-10 EP EP07826703A patent/EP2082411A2/en not_active Withdrawn
- 2007-10-10 JP JP2009531964A patent/JP2010507188A/en active Pending
- 2007-10-10 CN CNA2007800384029A patent/CN101523543A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102456527A (en) * | 2010-10-26 | 2012-05-16 | 通用电气公司 | Apparatus and method for improved transient response in an electromagnetically controlled X-ray tube |
| CN102456527B (en) * | 2010-10-26 | 2014-06-18 | 通用电气公司 | Apparatus and method for improved transient response in an electromagnetically controlled X-ray tube |
| CN104541332A (en) * | 2012-06-14 | 2015-04-22 | 伊克斯拉姆公司 | Limiting migration of target material |
| CN102842477A (en) * | 2012-09-20 | 2012-12-26 | 苏州生物医学工程技术研究所 | X-ray tube |
| CN104616952A (en) * | 2012-12-31 | 2015-05-13 | 同方威视技术股份有限公司 | Cathode-control multi-cathode distributed X-ray device |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2082411A2 (en) | 2009-07-29 |
| WO2008047267A3 (en) | 2008-09-04 |
| WO2008047267A2 (en) | 2008-04-24 |
| JP2010507188A (en) | 2010-03-04 |
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Open date: 20090902 |