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    • 专利摘要:
    The invention relates to a source generating ionizing rays and in particular X-rays, an assembly comprising a plurality of sources and a method for producing the source. The source generating ionizing rays comprises: a vacuum chamber (12), a cathode (14) capable of emitting an electron beam (18) in the vacuum chamber (12), an anode (16) receiving the electron beam (18) and comprising a target (20) capable of generating ionizing radiation (22) from the energy received from the electron beam (18); • an electrode (24) disposed in the vicinity of the electron beam (18); cathode (14) and for focusing the electron beam (18). According to the invention, the electrode (24) is formed of a conductive surface disposed on a concave face (26) of a dielectric material.
    公开号:FR3069098A1
    申请号:FR1700741
    申请日:2017-07-11
    公开日:2019-01-18
    发明作者:Pascal Ponard
    申请人:Thales SA；
    IPC主号:
    专利说明:

    Compact ionizing radiation generating source, assembly comprising several sources and method for producing the source
    The invention relates to a source generating ionizing rays and in particular X-rays, an assembly comprising several sources and a method for producing the source.
    X-rays today have many uses, notably in imaging and radiotherapy. X-ray imaging is widely used especially in the medical field, in industry to perform non-destructive testing and in security to detect dangerous objects or materials.
    X-ray imaging has come a long way. Originally only photosensitive films were used. Since then, digital detectors have appeared. These detectors, combined with software, allow rapid reconstruction of two-dimensional or three-dimensional images using scanners.
    On the other hand, since the discovery of X-rays by Rôntgen in 1895, X-ray generators have changed very little. Synchrotrons which appeared after the Second World War generate intense and well-focused radiation. The radiation is due to accelerations or deceleration of charged particles and possibly moving in a magnetic field.
    Linear accelerators and X-ray tubes use an accelerated electron beam bombarding a target. The braking of the beam due to the electric fields of the target's nuclei makes it possible to generate X-ray braking.
    An X-ray tube usually consists of an envelope in which the vacuum is created. The envelope is made up of a metallic structure and an electrical insulator in alumina or glass. In this envelope, two electrodes are arranged. A cathode electrode, brought to a negative potential, is equipped with an electron emitter. A second anode electrode, brought to a positive potential with respect to the first electrode, is associated with a target. The electrons, accelerated by the potential difference between the two electrodes, produce a continuous spectrum of ionizing rays by braking (bremsstralung) when they hit the target. The metal electrodes are necessarily large and have large radii of curvature in order to minimize the electric fields on their surface.
    Depending on the power of the X-ray tubes, they can be fitted with either a fixed anode or a rotating anode allowing spreading of the thermal power. Fixed anode tubes have a power of a few kilowatts and are used in particular in low power industrial, safety and medical applications. Rotating anode tubes can exceed 100 kilowatts and are mainly used in the medical environment for imaging requiring high X-ray fluxes to improve contrast. For example, the diameter of an industrial tube is around 150 mm at 450 kV, 100 mm at 220 kV and 80 mm at 160 kV. The indicated voltage corresponds to the potential difference applied between the two electrodes. For medical tubes with a rotating anode, the diameter varies from 150 to 300 mm depending on the power to be dissipated on the anode.
    The dimensions of the known X-ray tubes therefore remain large, of the order of several hundred mm. Imaging systems have seen the appearance of digital detectors with increasingly rapid and efficient 3D reconstruction software, while at the same time, X-ray tube technologies have practically not evolved for a century and this is a major technological limitation of X-ray imaging systems.
    Several factors stand in the way of the miniaturization of current X-ray tubes.
    The electrical insulators must have sufficient dimensions to guarantee good electrical insulation against high voltages from 30 kV to 300 kV. Sintered alumina, often used to make these insulators, typically has a dielectric strength of the order of 18 MV / m.
    The radius of curvature of the metal electrodes must not be too small in order to maintain a static electric field applied to the surface below an acceptable limit, typically 25 MV / m. Beyond the parasitic emissions of electrons by tunnel effect become difficult to control resulting in heating of walls, emissions of undesirable X-rays thus micro-discharges. Therefore, for high voltages, as encountered in X-ray tubes, the dimensions of the cathode electrodes are important in order to limit the parasitic emission of electrons.
    Thermoin cathodes are often used in conventional tubes. The dimensions of this type of cathode and their operating temperatures, typically greater than 1000 ° C., generate problems of expansion as well as the evaporation of electrically conductive elements such as barium. This makes miniaturization and integration of this type of cathode in contact with a dielectric insulator difficult.
    Surface charge phenomena linked to the Coulomb interaction appear on the surface of the dielectric materials used (Alumina or glass) when this surface is in the vicinity of an electron beam. In order to avoid proximity between the electron beam and the surface of the dielectric materials, an electrostatic screen is produced using a metal screen placed in front of the dielectric, or the distance of the electron beam from the dielectric . The presence of screens or the distance also tend to increase the dimensions of the X-ray tubes.
    The anode forming the target must dissipate significant thermal power. This dissipation can be achieved by circulating a heat transfer fluid or by making a large rotating anode. The need for this dissipation also requires increasing the dimensions of the X-ray tubes.
    Among the emerging technological solutions, the literature describes the use of cold carbon nanotube cathodes in X-ray tube structures, but the solutions currently proposed remain based on conventional X-ray tube structures using a metallic wehnelt. surrounding the cold cathode. This wehnelt is an electrode brought to a high voltage and is always subjected to important dimensional constraints to limit the stray emissions of electrons.
    The invention aims to overcome all or part of the problems mentioned above by proposing a source of ionizing radiation, for example in the form of a high voltage diode or triode, the dimensions of which are much smaller than those of ray tubes. Classic X's. The principle of generating ionizing radiation remains similar to that used in known tubes, namely an electron beam bombarding a target. The electron beam is accelerated between a cathode and an anode between which a potential difference is applied, for example greater than 100 kV. For the same potential difference, the invention makes it possible to significantly reduce the dimensions of the source according to the invention compared to known tubes.
    To achieve this goal, the invention exceeds a significant constraint on the level of the electric field on the surface of the cathode or wehnelt electrode. The constraint mentioned above is linked to the metallic nature of the interface between the electrode and the vacuum present in the enclosure in which the electron beam propagates. The invention mainly consists in replacing at the electrode level, the metal / vacuum interface with a dielectric / vacuum material interface which does not allow parasitic emission of electrons by tunnel effect. It is then possible to accept electric fields much higher than those acceptable with a metal / vacuum interface. Initial internal tests have shown that it is possible to reach static fields well above 30 MV / m without spurious emission of electrons. This dielectric / vacuum interface can for example be obtained by replacing the metal electrode whose external surface is subjected to the electric field by an electrode made of a dielectric material whose surface is subjected to the electric field and whose internal surface is coated with the perfectly adherent conductive deposit ensuring the function of electrostatic wehnelt. It is also possible to cover the external surface of a metal electrode subjected to the electric field with a dielectric material in order to replace the metal / vacuum interface of the known electrodes with a dielectric / vacuum interface where the electric field is important. This arrangement significantly increases the maximum electric field below which spurious electron emissions do not occur.
    The increase in admissible electric fields allows miniaturization of X-ray sources and more generally of ionizing radiation sources.
    More specifically, the subject of the invention is a source generating ionizing rays comprising:
    • a vacuum enclosure, • a cathode capable of emitting an electron beam in the vacuum enclosure, • an anode receiving the electron beam and comprising a target capable of generating ionizing radiation from the energy received from the beam of electrons, • an electrode placed in the vicinity of the cathode and making it possible to focus the electron beam, characterized in that the electrode is formed of a conductive surface arranged on a concave face of a dielectric material.
    Advantageously, the source comprises a mechanical part produced in the dielectric material, and comprising the concave face.
    Advantageously, the conductive surface is formed of a metal deposit arranged on the concave face.
    Advantageously, the mechanical part comprises an internal face having a surface resistivity of between 1.10 9 Ω.carred and 1.10 13 Ω.carred.
    Advantageously, the dielectric material is formed from a nitride-based ceramic.
    The surface resistivity of the internal face can be obtained by depositing a semiconductor material on the dielectric material of the mechanical part. Alternatively, the surface resistivity of the internal face can be obtained by adding a material to the volume of the nitride-based ceramic to reduce the intrinsic resistivity of the nitride-based ceramic.
    Advantageously, the cathode emits the electron beam by field effect and in that the electrode is placed in contact with the cathode.
    Advantageously, the mechanical part forms a support for the cathode.
    Advantageously, the mechanical part forms part of the vacuum enclosure.
    Advantageously, the mechanical part forms a support for the anode.
    Advantageously, the mechanical part comprises an external surface in the form of an internal truncated cone. The source comprises a support whose surface in the form of an external truncated cone is complementary to the external surface in the form of an internal truncated cone and at least one high-voltage contact supplying the cathode. The contact and the frusto-conical surfaces form a high voltage connector of the source.
    Advantageously, the source comprises a flexible seal disposed between the frusto-conical surface of the support and the frusto-conical surface of the mechanical part. The frusto-conical surface of the support has a more open apex angle than the frusto-conical surface of the mechanical part. The high voltage connector is configured so that air located between the two frusto-conical surfaces escapes inside the high voltage connector into a cavity not subjected to an electric field generated by a high voltage conveyed by the connector.
    Advantageously, the mechanical part comprises an outer surface in the form of an outer truncated cone. The support includes a surface in the form of an internal truncated cone complementary to the external surface in the form of an external truncated cone.
    Advantageously, the anode is tightly fixed to the mechanical part.
    Advantageously, the dielectric material has a dielectric rigidity greater than 30MV / m.
    The subject of the invention is also a set of generation of ionizing rays comprising:
    • several sources juxtaposed and stationary in the whole, • a control module configured to switch each of the sources according to a predetermined sequence.
    Advantageously, in the assembly comprising several sources, the mechanical part is common to all the sources.
    The sources can be aligned on an axis passing through each of the cathodes. The electrode is then advantageously common to the different sources.
    Advantageously, anodes from all sources are common.
    The invention also relates to a method for producing a source consisting in assembling on the mechanical part by translation along an axis of the electron beam, on the one hand the anode and on the other hand the cathode, a cavity formed by the concave face, being closed by a plug.
    The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, description illustrated by the attached drawing in which:
    Figure 1 shows schematically the main elements of an X-ray generating source according to the invention;
    FIG. 2 represents a variant of the source of FIG. 1 allowing other modes of electrical connection;
    Figure 3 is a partial and enlarged view of the source of Figure 1 around its cathode;
    Figures 4a and 4b are partial and enlarged views of the source of Figure 1 around its anode according to two variants;
    Figure 5 shows in section an integration mode comprising several sources according to the invention;
    Figures 6a 6b, 6c, 6d and 6e show variants of an assembly comprising several sources in the same vacuum enclosure;
    Figures 7a and 7b show several modes of electrical connection of an assembly comprising several sources.
    FIGS. 8a, 8b and 8c represent three examples of assemblies comprising several sources according to the invention and which can be produced according to the variants proposed in FIGS. 5 or 6.
    For the sake of clarity, the same elements will have the same references in the different figures.
    Figure 1 shows in section a source 10 generating X-rays. The source 10 comprises a vacuum chamber 12 in which are arranged a cathode 14 and an anode 16. The cathode 14 is intended to emit an electron beam 18 in the enclosure 12 in the direction of the anode 16. The anode 16 comprises a target 20 bombarded by the beam 18 and emitting X-ray radiation 22 as a function of the energy of the electron beam
    18. The beam 18 develops around an axis 19 passing through the cathode 14 and the anode 16.
    X-ray generating tubes conventionally use a thermionic cathode operating at high temperature, typically around 1000 ° C. This type of cathode is commonly called a hot cathode. This type of cathode composed of a metallic matrix or metallic oxides emits a flow of electrons caused by the vibrations of atoms due to thermal energy. However, hot cathodes suffer from several drawbacks, such as a weak temporal current control dynamic linked to the time constants of thermal processes, the need to use grids located between the cathode and the anode and polarized at high voltages in order to ability to monitor current. The grids are therefore located in an area of very strong electric fields, they are subjected to high operating temperatures around 1000 ° C. All of these constraints greatly limit the possibilities of integration and lead to large dimensions of the electron gun.
    More recently, cathodes operating on the principle of field emission have been developed. These cathodes operate at room temperature and are commonly called cold cathodes. Most of them consist of a flat conductive surface provided with raised structures, on which an electric field is concentrated. These relief structures are emitters of electrons when the field at the top is sufficiently high. The emitters in relief can be formed of carbon nanotubes. Such embodiments are for example described in the patent application published under the number WO 2006/063982 A1 and filed in the name of the applicant. Cold cathodes do not have the disadvantages of hot cathodes and are above all much more compact. In the example shown, the cathode 14 is a cold cathode and therefore emits the electron beam 18 by field effect. The control of the cathode 14 is not shown in FIG. 1. This control can be carried out electrically or optically as also described in the document WO 2006/063982 A1
    Under the effect of a potential difference between the cathode 14 and the anode 16, the electron beam 18 is accelerated and strikes the target 20 comprising for example a membrane 20a for example made of diamond or beryllium coated with a thin layer 20b made of an alloy based on material with a high atomic number such as in particular tungsten or molybdenum. The layer 20b can have a variable thickness for example between 1 and 12 μm depending on the energy of the electrons of the beam 18. The interaction between the electrons of the electron beam 18 accelerated at high speed and the material of the thin layer 20b Advantageously, X-ray radiation is produced 22. In the example shown, the target 20 forms a window of the vacuum enclosure 12. In other words, the target 20 forms part of the wall of the vacuum enclosure 12. This arrangement is in particular implemented for a target operating in transmission. For this arrangement, the membrane 20a is formed from a material with a low atomic number, such as diamond or beryllium for its transparency to X-ray radiation. The membrane 20a is configured to ensure vacuum tightness with the anode 16 enclosure 12.
    Alternatively, the target 20, or at least the layer produced in an alloy with a high atomic number, can be placed completely inside the vacuum enclosure 12 and the X-rays leave the enclosure 12 by passing through a window. forming a part of the wall of the vacuum enclosure 12. This arrangement is in particular implemented for a target operating in reflection. The target is then separate from the window. The layer in which X-rays are produced can be thick. The target can be fixed or rotating allowing spreading of the thermal power generated during the interaction with the electrons of beam 18.
    The source 10 comprises an electrode 24 arranged in the vicinity of the cathode 14 and making it possible to focus the electron beam 18. The invention is advantageously implemented with a so-called cold cathode. It is a cathode emitting an electron beam by field effect. This type of cathode is for example described in the document
    WO 2006/063982 A1 filed on behalf of the applicant. In the case of a cold cathode, the electrode 24 is arranged in contact with the cathode
    14. The electrode 24 is formed of a continuous conductive surface disposed on a concave face 26 of a dielectric material. The concave face 26 of the dielectric material forms a convex face of the electrode 24 facing the anode 16. It is from this convex face of the electrode 24 that large electric fields develop. In the prior art, a metal / vacuum interface exists on this convex face of the electrode. Consequently, this interface can be the seat of emission of electrons under the effect of the electric field inside the vacuum enclosure. This interface of the electrode with the vacuum of the enclosure is eliminated by replacing it with a dielectric / vacuum interface. A dielectric material, having no free charge, cannot therefore be the seat of a maintained electron emission.
    It is important to avoid any air or vacuum gap between the electrode 24 and the concave face 26 of the dielectric material. In fact, in the event of uncertain contact between the electrode 24 and the dielectric material, a very strong amplification of the electric field would appear at the interface and emissions of electrons or the development of a plasma could occur there. To this end, the source 10 comprises a mechanical part 28 formed in the dielectric material. One of the faces of the mechanical part 28 is the concave face 26. The electrode 24 is, in this case, constituted by a deposit of a conductive material perfectly adherent to the concave face 26. Different techniques can be used to produce this deposition, such as in particular the physical vapor deposition (known in the English literature under the acronym PVD for Physical Vapor Deposition) or chemical phase (CVD) possibly assisted by plasma (PECVD).
    Alternatively, it is possible to deposit a dielectric material on the surface of a massive metal electrode. The deposition of dielectric material always avoids any air or vacuum gap at the electrode / dielectric material interface. This deposit of dielectric material is chosen to withstand high electric fields, typically greater than 30 MV / m, and to have sufficient flexibility compatible with possible thermal expansion of the massive metal electrode. However, the reverse arrangement implementing the deposition of a conductive material on the internal face of a solid piece of dielectric material has other advantages, in particular that of allowing the use of the mechanical piece 28 to fulfill other functions. .
    More specifically, the mechanical part 28 can form a part of the vacuum enclosure 12. This part of the vacuum enclosure can even be a predominant part of the vacuum enclosure 12. In the example shown, the mechanical part 28 forms on the one hand a support for the cathode 14 and on the other hand a support for the anode 16. The part 28 provides electrical isolation between the anode 16 and the cathode electrode 24.
    For the production of mechanical part 28, the use of conventional dielectric materials such as, for example, sintered alumina, already makes it possible to avoid any metal / vacuum interface. However, the dielectric strength of this type of material, of the order of 18 MV / m, further limits the miniaturization of the source 10. To further miniaturize the source 10, a dielectric material is chosen having a dielectric rigidity greater than 20MV / m and advantageously greater than 30 MV / m. The value of the dielectric strength is for example maintained above 30 MV / m in a temperature range between 20 and 200 ° C. Composite ceramics of the nitride type make it possible to fulfill this criterion. Internal tests have shown that such a ceramic can even exceed 60 MV / m.
    By miniaturizing the source 10, surface charges can accumulate on an internal face 30 of the vacuum enclosure 12, and in particular the internal face of the mechanical part 28, when the electron beam 18 is established. It is useful to be able to drain these charges and for this purpose, the internal face 30 has a surface resistivity measured at ambient temperature between 1.10 9 Ω.carred and 1.10 13 Ω.carred and typically close to
    1.10 11 Ω square. Such resistivity can be obtained by adding a conductive or semiconductor material compatible with the dielectric material to the surface. As a semiconductor material, it is for example possible to deposit silicon on the internal face 30. In order to obtain the good resistivity range, for example for a nitride-based ceramic, it is possible to modify its intrinsic properties by adding a few percent (typically less than 10%) of a titanium nitride powder known for its low resistivity properties of the order of 4.10 3 cm or of semiconductor materials such as silicon carbide SiC .
    It is possible to disperse the titanium nitride in the volume of the dielectric material in order to obtain a homogeneous resistivity in the material of the mechanical part 28. Alternatively, it is possible to obtain a resistivity gradient by diffusing titanium nitride from the internal face 30 by a high temperature heat treatment greater than 1500 ° C.
    The source 10 comprises a plug 32 ensuring the tightness of the vacuum enclosure 12. The mechanical part 28 comprises a cavity 34 in which the cathode 14 is disposed. The cavity 34 is delimited by the concave face 26. The plug 32 closes the cavity 34. The electrode 24 comprises two ends 36 and 38 distant along the axis 19. The first end 36 is in contact with the cathode 14 and in electrical continuity therewith. The second end 38 is opposite the first. The mechanical part 28 comprises an inner truncated cone 40 of circular section disposed around the axis 19 of the bundle 18. The truncated cone 40 is located at the second end 38 of the electrode 24. The truncated cone 40 s 'opens away from the cathode 14. The plug 32 includes a shape complementary to the truncated cone 40 to be disposed there. The truncated cone 40 ensures the positioning of the plug 32 in the mechanical part 28. The plug 32 can be implemented independently of the production of the electrode 24 in the form of a conductive surface disposed on the concave face 26 of the dielectric material .
    Advantageously, the plug 32 is made of the same dielectric material as the mechanical part 28. This makes it possible to limit possible phenomena of differential thermal expansion between the mechanical part 28 and the plug 32 when the source 10 is used.
    The plug 32 is for example fixed to the mechanical part 28 by means of a brazing film 42 produced in the truncated cone 40 and more generally in an interface zone between the plug 32 and the mechanical part 28. It is possible to metallize the surfaces intended to be brazed with the plug 32 and the mechanical part 28 and then to make the solder by means of a metal alloy whose melting point is higher than the maximum temperature of use of the source 10. The metallization and the solder film 42 come in electrical continuity with the end 38 of the electrode 24. The frustoconical shape of the metallized interface between the plug 32 and the mechanical part 28 makes it possible to avoid angular shapes which are too pronounced for the electrode 24 and for the conductive areas extending the electrode 24 in order to limit possible peak effects of the electric field.
    Alternatively, it is possible to avoid metallization of the surfaces by integrating into the brazing alloy an active element which reacts with the material of the plug 32 and that of the mechanical part 28. For ceramics based on nitride, titanium is integrated in the brazing alloy. Titanium is a metal that reacts with nitrogen and creates a strong chemical bond with ceramic. Other reactive metals can be used such as vanadium, niobium or zirconium.
    Advantageously, the solder film 42 is conductive and is used to electrically connect the electrode 24 to a supply from the source 10. The electrical connection of the electrode 24 by means of the solder film 42 can be implemented for other types of electrodes, in particular metal electrodes covered with a deposit of dielectric material. To strengthen the connection with the electrode 24, it is possible to drown a metallic contact in the solder film 42. This contact is advantageous for connecting a solid metal electrode covered with a deposit of dielectric material. The electrical connection of electrode 24 is provided by this electrical contact. Alternatively, it is possible to partially metallize a surface 43 of the plug 32. The surface 43 is located outside the vacuum enclosure 12. The metallization of the surface 43 is in electrical contact with the solder film 42. It is possible to solder on the metallization of the surface 43 a contact which can be electrically connected to a supply of the source 10.
    The solder film 42 prolongs the shape of revolution of the electrode 24 and in fact contributes to the main function of the electrode 24. This is particularly advantageous when the electrode 24 is formed from a conductive surface arranged on the concave face. 26. The solder film 42 extends the conductive surface forming the electrode 24 directly and without discontinuity or angular point moving away from the axis 19. The electrode 24, associated with the solder film 42 when it is conductive, form an equipotential surface which contributes to the focusing of the electron beam 18 and to the potentialization of the cathode 14. This makes it possible to minimize the local electric fields to gain in compactness of the source 10.
    The face 26 may have locally convex zones, such as for example at its junction with the truncated cone 40. In practice, the face 26 is at least partially concave. The face 26 is generally concave.
    In FIG. 1, the source 10 is polarized by means of a high voltage source 50, a negative terminal of which is connected to the electrode 24, for example through the metallization of the solder film 42 and of which a positive terminal is connected at the anode 16. This type of connection is characteristic of a monopolar operation of the source 10 in which the potential of the anode 16 is earthed 52. It is also possible to replace the high voltage source 50 by two high voltage sources 56 and 58 in series to operate the source 10 in a bipolar manner as shown in FIG. 2. This type of operation is advantageous for simplifying the production of the associated high voltage generator. For example in the case of a high-frequency pulsed high-frequency operating mode, it may be advantageous to lower the absolute voltage by summing the two positive and negative half voltages at the source 10. For this purpose, the high voltage source may include an output transformer controlled by a half-H bridge.
    With a source 10 as shown in FIG. 1, the bipolar operation can be done by connecting the common point of the generators 56 and 58 to earth 52. Alternatively, it is also possible to keep the high voltage source 50 floating relative to earth 52 as in figure 2.
    Bipolar operation of a source as described in Figure 1 is done by keeping floating the common point of two high voltage sources connected in series. Alternatively, this common point can be used to polarize another electrode of the source 10 as shown in FIG. 2. In this variant, the source 10 comprises an intermediate electrode 54 dividing the mechanical part 28 into two parts 28a and 28b. intermediate electrode 54 extends perpendicularly to the axis 19 of the beam 18 and is crossed by the beam 18. The presence of the electrode 54 allows bipolar operation by connecting the electrode 54 to the common point of the two high voltage sources 56 and 58 connected in series. In FIG. 2, the assembly formed by the two high voltage sources 56 and 58 is floating relative to the earth 52. As shown in FIG. 1, it is also possible to connect to the earth 52, one of the electrodes from the source 10, for example the intermediate electrode 54.
    FIG. 3 is a partial and enlarged view of the source 10 around the cathode 14. The cathode 14 is disposed in the cavity 34 bearing against the end 36 of the electrode 24. A support 60 makes it possible to center the cathode 14 with respect to the electrode 24. Since the electrode 24 is of revolution about the axis 19, the cathode 14 is therefore centered on the axis 19 allowing it to emit the electron beam 18 along the axis 19. The support 60 comprises a counterbore 61 centered on the axis 19 and in which the cathode 14 is disposed. At its periphery, the support 60 comprises an annular zone 63 centered in the electrode 24. A spring 64 bears on the support 60 of so as to keep the cathode 14 in abutment against the electrode 24. The support 60 is made of insulating material. The spring 64 may have an electrical function making it possible to convey a control signal to the cathode 14. More specifically, the cathode 14 emits the electron beam 18 through a face 65, called the front face and oriented towards the anode 16. The electrical control of the cathode 14 is done by its rear face 66 opposite the front face 65. The support 60 can comprise an opening 67 with circular section centered on the axis 19. The opening 67 can be metallized so to electrically connect the spring 64 and the rear face 66 of the cathode 14. The plug 32 can ensure the electrical connection of the control of the cathode 14 by means of a metallized via 68 passing therethrough and of a contact 69 integral with the plug 32. The contact 69 presses on the spring 64 along the axis 19 to keep the cathode 14 in abutment against the electrode 24. The contact 69 ensures electrical continuity between the via 68 and the spring 64.
    The surface 43 of the plug 32, located outside the vacuum enclosure 12, can be metallized into two distinct zones: a zone 43a centered on the axis 19 and a peripheral annular zone 43b around the axis 19. The metallized zone 43a is in electrical continuity with the metallized via 68. The metallized zone 43b is in electrical continuity with the solder film 42. A central contact 70 comes to bear against the area 43a and a peripheral contact 71 comes to bear against the zone 43b. The two contacts 70 and form a coaxial connector ensuring the electrical connection of the cathode 14 and the electrode 24 via the metallized zones 43a and 43b and via the metallized via 68 and the solder film 42.
    The cathode 14 can comprise several distinct emitting zones which can be addressed separately. The rear face 66 then has several separate electrical contact zones. The support 60 and the spring 64 are adapted accordingly. Several contacts similar to contact 69 and several metallized vias similar to via 68 make it possible to connect the different zones of the rear face 66. The surface 43 of the plug 32, the contact 69 as well as the spring 64 are sectorized accordingly to provide several zones there. similar to zone 43a and in electrical continuity with each of the metallized vias.
    At least one sorber 35 (known in the Anglo-Saxon literature under the name of "getter") can be placed in the cavity 34, between the cathode 14 and the plug 32, in order to trap any particle capable of altering the quality of the vacuum of the enclosure 12. The sorber 35 generally acts by chemisorption. Alloys based on zirconium or titanium can be used to trap possible particles emitted by the various components of the source 10 surrounding the cavity 34. The sorber 35 is, in the example shown, fixed to the plug 32. The absorber 35 is produced from annular discs stacked and surrounding the contact 69.
    FIG. 4a represents a variant of a source of ionizing radiation 75 in which an anode 76 replaces the anode 16 described above. FIG. 4a is a partial and enlarged view of the source 75 around the anode 76. As for the anode 16, the anode 76 comprises a target 20 bombarded by the beam 18 and emitting X-radiation 22. Unlike from the anode 16, the anode 76 comprises a cavity 80 into which the electron beam 18 penetrates to reach the target 20. More precisely, the electron beam 18 strikes the target 20 by its internal face 84 carrying the layer thin 20b and emits X-rays 22 through its external face 86. In the example shown, the walls of the cavity 80 have a cylindrical part 88 around the axis 19 extending between two ends 88a and 88b. The end 88a is in contact with the target 20 and the end 88b approaches the cathode 14. The walls of the cavity 80 also have a part 90 in the form of a washer having a hole 89 and closing the cylindrical part at the level of the end 88b. The electron beam 18 enters the cavity 80 through the hole 89 of the part 90.
    During the bombardment of the target 20 by the electron beam 18, the temperature rise of the target 20 can cause molecular degassing of the target 20 which, under the effect of X-rays 22, are ionized. Ions 91 appearing on the inner face 84 of the target 20 can damage the cathode if they return to the accelerating electric field located between the anode and the cathode. Advantageously, the walls of the cavity 80 can be used to trap the ions 91. To this end, the walls 88 and 90 of the cavity 80 are electrical conductors and form a faraday cage with respect to parasitic ions which can be emitted by the target 20 inside the vacuum enclosure 12. The ions 91 possibly emitted by the target 20 towards the interior of the vacuum enclosure 12 are largely trapped in the cavity 80. Only the hole 89 of the part 90 allows the ions to exit from the cavity 80 and could be accelerated towards the cathode 14. To better trap the ions in the cavity 80, at least one sorber 92 is disposed in the cavity 80. Like the sorber 34 , the adsorber 92 generally acts by chemisorption. Zirconium or titanium-based alloys can be used to trap the 91 ions emitted.
    In addition to the trapping of ions, the walls of the cavity 80 can form a shielding screen against parasitic ionizing radiation 82 generated inside the vacuum enclosure 12 and possibly an electrostatic shielding of the electric field. generated between the cathode 14 and the anode 76. The X-ray 22 forms the useful radiation emitted by the source 75. However, parasitic X-radiation can exit from the target 20 by the internal face 84. This parasitic radiation is useless and undesirable . Usually, shielding screens opposing this type of stray radiation are placed around the X-ray generators. However, this type of embodiment has a drawback. In fact, the further the shielding screens are placed from the X-ray source, that is to say away from the target 20, the more the screens require material surface due to their distance. This aspect of the invention proposes to have such screens as close as possible to the parasitic source, which makes it possible to miniaturize them.
    The anode 76 and in particular the walls of the cavity 80 are advantageously made of a material with a high atomic number, for example in an alloy based on tungsten or molybdenum in order to stop the stray radiation 82.
    The walls of the cavity 80 surround the electron beam 18 in the vicinity of the target 20.
    Advantageously, the walls of the cavity 80 form part of the vacuum enclosure 12.
    Advantageously, the walls of the cavity 80 are arranged coaxially with the axis 19 so as to be located radially around the axis 19 at a constant distance and therefore as close as possible to the parasitic radiation. At the end 88a, the cylindrical part 88 can partially or totally surround the target 20, thus preventing any stray radiation X from escaping from the target 20 radially with respect to the axis 19.
    Thus the anode 76 fulfills several functions, its electrical function of course, moreover, a faraday cage function surrounding parasitic ions which can be emitted by the target 20 inside the vacuum enclosure 12, a function of shielding against parasitic X-radiation and, moreover, a wall of the vacuum enclosure 12. By fulfilling several functions by means of a single mechanical part, in this case the anode 76, the source 75 becomes more compact and by weight.
    Furthermore, around the cavity 80, it is possible to have at least one magnet or electromagnet 94 making it possible to focus the electron beam 18 towards the target 20. Advantageously, the arrangement of the magnet or electromagnet 94 can be also defined so as to deflect the parasitic ions 91 towards the absorber (s) 92 in order to avoid that the parasitic ions cannot leave the cavity through the hole 89 of the part 90 or at least are deviated with respect to the axis 19 passing through the cathode 14. For this purpose, the magnet or the electromagnet 94 generates a magnetic field B oriented along the axis 19. In FIG. 4a, the ions 91 deflected towards the sorber 92 follow a path 91a and the ions leaving cavity 80 follow a path 91b.
    The means for trapping the parasitic ions 91 which can be emitted by the target 20, are multiple: faraday cage formed by the walls of the cavity 80, presence of sorbers 92 in the cavity 80 and presence of a magnet or electromagnet 94 for deflect parasitic ions. These means can be implemented independently or in addition to the shielding function against parasitic X-radiation and the wall function of the vacuum chamber 12.
    The anode 76 is advantageously produced in the form of a one-piece mechanical part of revolution around the axis 19. The cavity 80 forms a central tubular part of the anode 76. The magnet or electromagnet 94 is arranged around the cavity 80 in an annular space 95 advantageously located outside of the vacuum enclosure 12. So that the magnetic flux of the magnet or electromagnet 94 affects the electron beam 18 as well as the ions degassed by the target 20 at the inside the enclosure 12, the walls of the cavity 80 are made of non-magnetic material. More generally, all of the anode 76 is made of the same material, for example by machining.
    The adsorber 92 is located in the cavity 80 and the magnet or the electromagnet 94 is located outside the cavity. Advantageously, a mechanical support 97 of the adsorber 92 maintains the adsorber 92 and is made of magnetic material. The support 97 is arranged in the cavity so as to guide the magnetic flux coming from the magnet or the electromagnet 94. In the case of an electromagnet 94, it can be formed around a magnetic circuit 99. The support 97 is advantageously arranged in the extension of the magnetic circuit 99. The fact of using the mechanical support 97 to fulfill two functions: maintaining the sorber 92 and guiding a magnetic flux makes it possible to further reduce the dimensions of the anode 76 and therefore from source 75.
    At the periphery of the annular space 95, the anode comprises a support area 96 on the mechanical part 28. The support area 96 has for example the shape of a flat washer extending perpendicular to the axis
    19.
    In FIG. 4a, an orthogonal coordinate system X, Y, Z is defined. Z is a direction carried by the axis 19. The field Bz, carried by the axis Z makes it possible to focus the electron beam 18 on the target 20 The size of the electronic spot 18a on the target 20 is shown near the target 20 in the XY plane. The electronic spot 18a is circular. The size of the X-ray spot 22a emitted by the target 20 is also shown near the target 20 in the XY plane. Since the target 20 is perpendicular to the axis 19, the X-ray spot 22a is also circular.
    FIG. 4b represents a variant of the anode 76 in which a target 21 is inclined relative to the XY plane perpendicular to the axis 19. This inclination makes it possible to enlarge the surface of the target 20 bombarded by the beam of electrons 18. By enlarging this surface, the increase in temperature of target 20 due to the interaction with electrons is better distributed. When the source 75 is used for imaging, it is useful to keep an X-ray spot 22a as punctual as possible or at least circular as in the variant of FIG. 4a. To keep this spot 22a, with an inclined target 21, it is useful to modify the shape of the electronic spot in the XY plane. For the variant of FIG. 4b, the electronic spot carries the mark 18b and is represented near the target 21 in its mark XY. The spot is advantageously elliptical in shape. Such a spot shape can be obtained from emitting zones of the cathode distributed in the plane of the cathode in a shape similar to the shape desired for the spot 18b. Alternatively or in addition, it is possible to modify the shape of the section of the electron beam 18 by means of a magnetic field By oriented along the Y axis and for example generated by a quadrupole having windings 98 also located in the annular space 95. The quadrupole forms an active magnetic system generating a magnetic field transverse to the axis 19 making it possible to obtain the shape expected for the electronic spot 18b. For example, for a target inclined relative to the direction X, the electron beam 18 is spread out in the direction X and is concentrated in the direction Y in order to maintain a circular X-ray spot 22a. The active magnetic system can also be controlled so as to obtain other forms of electronic spot and possibly other forms of X-ray spot. The active magnetic system is of particular interest when the target 21 is tilted. The active magnetic system can also be used with a target 20 perpendicular to the axis 19.
    The anodes 16 and 76 in all their variants can be implemented independently of the production of the electrode 24 in the form of a conductive surface disposed on the concave face 26 of the dielectric material and independently of the implementation of the plug
    32.
    In the variants proposed using FIGS. 1 to 4, all the components can be assembled by translation of each along the same axis, in this case axis 19. This makes it possible to simplify the production of a source conforming to the invention by automating its manufacture.
    More specifically, the mechanical part 28 made of dielectric material and on which various metallizations have been carried out, in particular the metallization forming the electrode 24, forms a monolithic support. It is possible to assemble on one side of this support, the cathode 14 and the plug 32. On the other side of this support, it is possible to assemble the anode 16 or 76. The fixing of the anode 16 or 76 and of the plug 32 on the mechanical part 28 can be produced by brazing under ultra vacuum. The target 20 or 21 can also be assembled by translation along the axis 19 on the anode 76.
    FIG. 5 shows two identical sources 75 mounted in the same support 100. This mounting example can be used for mounting more than two sources. This example also applies to sources 10. Sources 10 as shown in FIGS. 1 and 2 can also be mounted in the support 100. The description of the support 100 and additional parts can apply regardless of the number of sources . The mechanical part 28 advantageously has a surface external to the vacuum enclosure 12 having two frustoconical shapes 102 and 104 extending around the axis 19. The shape 102 is an outer truncated cone widening towards the anode 16 The form 104 is an inner truncated cone flaring from the cathode 14 and more precisely from the outer face 43 of the plug 32. The two truncated cones 102 and 104 meet on a crown 106 also centered on the axis 19. The crown 106 forms the smallest diameter of the truncated cone 102 and the largest diameter of the truncated cone 104. The crown 106 for example has the shape of a portion of a torus allowing a connection without sharp angles of the two truncated cones 102 and 104. The shape of the external surface of the mechanical part 28 facilitates the positioning of the source 75 in the support
    100 which has a complementary surface also having two frustoconical shapes 108 and 110. The truncated cone 108 of the support 100 is complementary to the truncated cone 102 of the mechanical part 28. Similarly, the truncated cone 110 of the support 100 is complementary to the truncated cone 104 of the mechanical part 28. The support 100 has a crown 112 complementary to the crown 106 of the mechanical part 28.
    In order to avoid any air gap at the high voltage interface between the support 100 and the mechanical part 28, a flexible seal 114, for example based on silicone, is placed between the support 100 and the mechanical part 28 and more precisely between the trunks of cones and complementary crowns. Advantageously, the truncated cone 108 of the support 100 has a more open apex angle than that of the truncated cone 102 of the mechanical part 28. Similarly the truncated cone 110 of the support 100 has a more open apex angle than that of the truncated cone 104 of the mechanical part 28. The difference in angle value at the apex between the truncated cones can be less than 1 degree, for example of the order of 0.5 degree. Thus when the source 75 is mounted in its support 100, and more precisely when the seal 114 is crushed between the support 100 and the mechanical part 28, air can escape from the interface between the rings 106 and 112 on the one hand towards the most flared part of the two truncated cones 102 and 108 in the direction of the anode 16 and on the other hand towards the most constricted part of the two truncated cones 104 and 110 in the direction of the cathode 14 and more precisely in the direction of the plug 32. The air located between the two truncated cones 102 and 108 escapes towards the ambient air and the air located between two truncated cones 104 and 110 escapes towards the plug 32. In order to prevent trapped air from being subjected to a strong electric field, the source 75 and its support 100 are configured so that the air located between two truncated cones 104 and 110 escapes inside. of the coaxial connection formed by the two contacts 70 and 71 e t supplying the cathode 14. To do this, the external contact 71 ensuring the supply of the electrode 24 comes into contact with the metallized zone 43b by means of a spring 116 allowing a functional clearance between the contact 71 and the plug 32 In addition, the plug 32 may include an annular groove 118 separating the two metallized zones 43a and 43b. Thus the air escaping between the trunks of cones 104 and 110 crosses the functional clearance between the contact 71 and the plug 32 to reach a cavity 120 located between the contacts 70 and 71. This cavity 120 is protected from the large electric field because being located inside the coaxial contact 71.
    In other words, the cavity 120 is screened with the main electric field of the source 10, electric field due to the potential difference between the anode 16 and the cathode electrode 24.
    After mounting the mechanical part 28 equipped with its cathode 14 and its anode 76, a closure plate 130 can ensure the maintenance of the mechanical part 28, equipped with its cathode 14 and its anode 76, in the support 100. The plate 130 can be made of conductive material or comprise a metallized face to ensure the electrical connection of anode 76. Plate 130 can allow cooling of anode 76. Cooling can be provided for conduction by means of a contact between the anode 76 and for example the cylindrical part 88 of the cavity 80 of the anode 76. To reinforce this cooling, it is possible to provide a channel 132 arranged in the plate 130 and surrounding the cylindrical part 88. A heat transfer fluid circulates in channel 132 to cool the anode 76.
    In FIG. 5, the sources 75 all have separate mechanical parts 28. FIG. 6a represents a variant of a multi-source assembly 150 in which a mechanical part 152 common to several sources 75, four in the example shown, fulfills all the functions of the mechanical part 28. The vacuum chamber 153 is common to the different sources 75. The support 152 is advantageously formed from a dielectric material in which, for each of the sources 75, a concave face 26 is produced. For each of the sources, an electrode 24 (not shown) is arranged on the corresponding concave face 26. In order not to overload the figure, the cathodes 14 of the different sources 75 are not shown.
    In the variant of FIG. 6a, the anodes of all the sources 75 are advantageously common and together bear the reference 154. To facilitate their production, the anodes comprise a plate 156 in contact with the mechanical part 152 and pierced with 4 holes 158 allowing each the passage of an electron beam 18 from each of the cathodes of the sources 75. The plate 156 fills, for each of the sources
    75, the function of part 90 described above. Above each hole
    158, are arranged a cavity 80 limited by its wall 88 and a target
    20. Alternatively, it is possible to keep separate anodes which allows their electrical connection to be dissociated.
    FIG. 6b represents another variant of a multi-source assembly 160 in which a mechanical part 162 is also common to several sources, the respective cathodes 14 of which are aligned on an axis 164 passing through each of the cathodes 14. The axis 164 is perpendicular to axis 19 of each of the sources. An electrode 166 for focusing the electron beams emitted by the different cathodes 14 is common to all the cathodes 14. The variant of FIG. 6b makes it possible to further reduce the distance separating two neighboring sources.
    In the example shown, the mechanical part 162 is made of dielectric material and comprises a concave face 168 disposed in the vicinity of the different cathodes 14. The electrode 166 is formed of a conductive surface disposed on the concave face 168. The electrode 166 fulfills all the functions of the electrode 24 described above.
    Alternatively, it is possible to use an electrode common to several sources in the form of a metal electrode without the presence of dielectric material, that is to say having a metal / vacuum interface. Similarly, the cathodes can be thermionic. In this embodiment, the common metal electrode forms the support for the different cathodes of the different sources. Since this electrode is large, it is advantageous to connect it to the ground of the generator of the multi-source assembly. The anode (s) are then connected to one or more positive potentials of the generator.
    The multi-source assembly 160 may include a plug 170 common to all the sources. The plug 170 can fulfill all the functions of the plug 32 described above. The plug 170 can in particular be fixed to the mechanical part 162 by means of a conductive solder film 172 used to electrically connect the electrode 166.
    As in the variant of FIG. 6a, the multi-source assembly 160 may include an anode 174 common to the different sources. Anode 174 is similar to anode 154 of the variant in FIG. 6a. The anode 174 comprises a plate 176 fulfilling all the functions of the plate 156 described with the aid of FIG. 6a. To avoid overloading the figure
    6b, for anode 174, only plate 176 is shown.
    In FIG. 6b, the axis 164 is rectilinear. It is also possible to arrange the cathodes on a curved axis, such as for example an arc of a circle as shown in FIG. 6c making it possible to focus the X-rays 22 from all the sources at a point located in the center of the arc of a circle . Other forms of curved axis, in particular a parabolic curve, also allow the focusing of X-rays at a point. The curved axis remains locally perpendicular to each of the axes 19 around which the electron beam of each source develops.
    The arrangement of the cathodes 14 on an axis makes it possible to obtain sources distributed in a direction. It is also possible to produce a multi-source assembly in which the cathodes are distributed along several concurrent axes. It is for example possible to arrange the sources along several curved axes, each produced in a plane and the planes being intersecting. By way of example, as shown in FIG. 6d, it is for example possible to have several axes 180 and 182 distributed over a parabolic surface of revolution 184. This makes it possible to focus the X-rays 22 from all the sources at the focus of the parabolic surface. In FIG. 6e, the different axes 190, 192 and 194 on which the different cathodes 14 of the multi-source assembly are distributed are parallel to each other.
    Figures 7a and 7b show two embodiments of the power supply of the assembly shown in Figure 6a. Figures 7a and 7b are shown in section in a plane passing through several axes 19 of different sources 75. Two sources appear in Figure 7a, and three sources in Figure 7b. It is understood that the description of the multi-source assembly 150 can be implemented regardless of the number of sources 75 or possibly 10.
    In these two embodiments, the anodes 114 are common to all the sources 75 of the assembly 150 and their potential is the same, for example that of the earth 52. The control of each of the sources 10 can be distinct in the two embodiments. In FIG. 7a, two high voltage sources V1 and V2 separately supply the electrodes of each of the sources 10. The insulating nature of the mechanical part
    152 makes it possible to separate the two high voltage sources V1 and V2 which can, for example, be pulsed at two different energies. Similarly, separate current sources 11 and I2 each control the different cathodes 14.
    In the embodiment of FIG. 7b, the electrodes 24 of all the sources 75 are connected together for example by means of a metallization produced on the mechanical part 152. A high voltage source V Co mmun supplies all the electrodes 24. The piloting of the different cathodes 14 remains ensured by separate current sources 11 and I2. The electrical supply of the multi-source assembly described using FIG. 7b is well suited to the variant described using FIGS. 6b, 6d and 6e.
    FIGS. 8a, 8b and 8c represent several examples of sets of generation of ionizing rays each comprising several sources 10 or 75. In these various examples, the support, as described with the aid of FIG. 5 is common to all sources 10. A high voltage connector 140 enables the various sources to be supplied. A pilot connector 142 makes it possible to connect each of the assemblies to a pilot module not shown and configured to switch each of the sources 10 according to a predetermined sequence.
    In FIG. 8a, the support 144 has a shape in an arc of a circle and the different sources 10 are aligned on the shape in an arc of a circle. This type of arrangement is for example useful in a medical scanner in order to avoid moving the X-ray source around the patient. The different sources 10 each emit X-ray radiation in turn. The scanner also includes a radiation detector and a module making it possible to reconstruct an image in 3 dimensions from information captured by the detector. In order not to overload the figure, the detector and the reconstruction module are not shown. In FIG. 8b, the support 146 and the sources 10 follow a straight line segment. In FIG. 8c, the support 148 has the form of a plate and the sources are distributed in two directions on the support 148. For the generating sets of ionizing rays shown in FIGS. 8a and 8b, the variant of FIG. 6b is particularly interesting. This variant makes it possible to reduce the pitch between the different sources.
    权利要求:
    Claims (21)
    [1" id="c-fr-0001]
    1. Source generating ionizing rays comprising:
    • a vacuum enclosure (12; 153), • a cathode (14) capable of emitting an electron beam (18) in the vacuum enclosure (12; 153), • an anode (16; 76; 154; 174 ) receiving the electron beam (18) and comprising a target (20; 21) capable of generating ionizing radiation (22) from the energy received from the electron beam (18), • an electrode (24; 166 ) arranged in the vicinity of the cathode (14) and making it possible to focus the electron beam (18), characterized in that the electrode (24) is formed of a conductive surface arranged on a concave face (26; 168) of a dielectric material.
    [2" id="c-fr-0002]
    2. Source according to claim 1, characterized in that it comprises a mechanical part (28; 152; 162) made of the dielectric material, and comprising the concave face (26; 168).
    [3" id="c-fr-0003]
    3. Source according to claim 2, characterized in that the conductive surface is formed of a metal deposit disposed on the concave face (26; 168).
    [4" id="c-fr-0004]
    4. Source according to one of claims 2 or 3, characterized in that the mechanical part (28; 152; 162) comprises an internal face (30) having a surface resistivity between 1.10 9 Ω.carré and 1.10 13 Q .square.
    [5" id="c-fr-0005]
    5. Source according to one of the preceding claims, characterized in that the dielectric material is formed from a nitride-based ceramic.
    [6" id="c-fr-0006]
    6. Source according to claims 4 and 5, characterized in that the surface resistivity of the internal face (30) is obtained by deposition, on the dielectric material of the mechanical part (28; 152; 162), of a material semiconductor.
    [7" id="c-fr-0007]
    7. Source according to claims 4 and 5, characterized in that the surface resistivity of the internal face (30) is obtained by adding in the volume of the nitride-based ceramic a material making it possible to reduce the intrinsic resistivity of the nitride-based ceramic.
    [8" id="c-fr-0008]
    8. Source according to one of the preceding claims, characterized in that the cathode (14) emits the electron beam (18) by field effect and in that the electrode (24; 166) is arranged in contact with the cathode (14).
    [9" id="c-fr-0009]
    9. Source according to one of claims 2 to 8 as a dependent claim of claim 2, characterized in that the mechanical part (28; 152; 162) forms a support for the cathode (14).
    [10" id="c-fr-0010]
    10. Source according to one of claims 2 to 9 as a dependent claim of claim 2, characterized in that the mechanical part (28; 152; 162) forms a part of the vacuum enclosure (12).
    [11" id="c-fr-0011]
    11. Source according to one of claims 2 to 10 as a dependent claim of claim 2, characterized in that the mechanical part (28; 152; 162) forms a support for the anode (16; 76; 154) .
    [12" id="c-fr-0012]
    12. Source according to one of claims 2 to 11 as a dependent claim of claim 2, characterized in that the mechanical part (28; 152; 162) comprises an outer surface in the form of an inner truncated cone (104) , in that the source (10; 76; 154) comprises a support (100) whose surface (110) in the form of an external truncated cone is complementary to the external surface in the form of an internal truncated cone (104) and at at least one high voltage contact (71) supplying the cathode (14) and in that the contact and the frusto-conical surfaces (104, 110) form a high voltage connector of the source (10; 76; 154).
    [13" id="c-fr-0013]
    13. Source according to claim 12, characterized in that it comprises a flexible seal (114) disposed between the surface (110) in the form of a truncated cone of the support (100) and the surface (104) in the form of a trunk of cone of the mechanical part (28; 152), in that the surface (110) in the form of a truncated cone of the support (100) has a more open apex angle than the surface (104) in the form of a truncated cone of the mechanical part (28; 152) and in that the high-voltage connector is configured so that air located between the two frusto-conical surfaces (104, 110) escapes inside the high connector voltage in a cavity (120) not subjected to an electric field generated by a high voltage conveyed by the connector.
    [14" id="c-fr-0014]
    14. Source according to one of claims 12 or 13, characterized in that the mechanical part (28; 152; 162) comprises an outer surface in the form of an outer truncated cone (102), in that the support (100) including a surface (108) in the form of an internal truncated cone complementary to the external surface in the form of an external truncated cone (102).
    [15" id="c-fr-0015]
    15. Source according to one of claims 2 to 14 as a dependent claim of claim 2, characterized in that the anode (16; 76; 154; 174) is tightly fixed to the mechanical part (28; 152; 162).
    [16" id="c-fr-0016]
    16. Source according to one of the preceding claims, characterized in that the dielectric material has a dielectric strength greater than 30MV / m.
    [17" id="c-fr-0017]
    17. Ionizing ray generation assembly characterized in that it comprises:
    • several sources (10, 75) according to one of the preceding claims, the sources being juxtaposed and stationary in the assembly, • a control module configured to switch each of the sources according to a predetermined sequence.
    [18" id="c-fr-0018]
    18. An assembly according to claim 17 and comprising several sources according to claim 2, characterized in that the mechanical part (152; 162) is common to all the sources (10, 75).
    [19" id="c-fr-0019]
    19. The assembly of claim 18, characterized in that the sources are aligned on an axis passing through each of the cathodes (14) and in that the electrode (166) is common to the different sources.
    [20" id="c-fr-0020]
    20. Assembly according to one of claims 17 to 19, characterized in that the anodes (154; 174) from all the sources (10, 75) are common.
    [21" id="c-fr-0021]
    21. A method of producing a source according to claims 4 and 6, characterized in that it consists in assembling on the mechanical part (28; 152; 162) by translation along an axis (19) of the electron beam ( 18), on the one hand the anode (16; 76; 154; 174) and on the other hand the cathode (14), a cavity (34) formed by the concave face (26), being closed by a plug ( 32; 170).
    类似技术:
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    同族专利:
    公开号 | 公开日
    US11004647B2|2021-05-11|
    WO2019011980A1|2019-01-17|
    IL271796D0|2020-02-27|
    KR20200024211A|2020-03-06|
    ES2881314T3|2021-11-29|
    CN110870036A|2020-03-06|
    JP2020526868A|2020-08-31|
    TW201909226A|2019-03-01|
    SG11201912205QA|2020-01-30|
    AU2018298781A1|2019-12-19|
    US20200203113A1|2020-06-25|
    FR3069098B1|2020-11-06|
    EP3652773B1|2021-05-26|
    EP3652773A1|2020-05-20|
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    法律状态:
    2019-01-18| PLSC| Publication of the preliminary search report|Effective date: 20190118 |
    2020-06-25| PLFP| Fee payment|Year of fee payment: 4 |
    2021-06-24| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1700741|2017-07-11|
    FR1700741A|FR3069098B1|2017-07-11|2017-07-11|COMPACT IONIZING RAY GENERATOR SOURCE, ASSEMBLY INCLUDING SEVERAL SOURCES AND PROCESS FOR REALIZING THE SOURCE|FR1700741A| FR3069098B1|2017-07-11|2017-07-11|COMPACT IONIZING RAY GENERATOR SOURCE, ASSEMBLY INCLUDING SEVERAL SOURCES AND PROCESS FOR REALIZING THE SOURCE|
    TW107123868A| TW201909226A|2017-07-11|2018-07-10|a miniature source for generating free radiation, an assembly comprising a plurality of sources, and a process for manufacturing the source|
    ES18736941T| ES2881314T3|2017-07-11|2018-07-11|Compact ionizing ray generator source, set comprising several sources and procedure for making the source|
    US16/612,738| US11004647B2|2017-07-11|2018-07-11|Compact source for generating ionizing radiation, assembly comprising a plurality of sources and process for producing the source|
    JP2019561262A| JP2020526868A|2017-07-11|2018-07-11|Small sources for producing ionizing radiation, assemblies with multiple sources, and processes for producing sources|
    PCT/EP2018/068779| WO2019011980A1|2017-07-11|2018-07-11|Compact, ionising ray-generating source, assembly comprising a plurality of sources and method for producing the source|
    SG11201912205QA| SG11201912205QA|2017-07-11|2018-07-11|Compact source for generating ionizing radiation, assembly comprising a plurality of sources and process for producing the source|
    EP18736941.8A| EP3652773B1|2017-07-11|2018-07-11|Compact, ionising ray-generating source, assembly comprising a plurality of sources and method for producing the source|
    AU2018298781A| AU2018298781A1|2017-07-11|2018-07-11|Compact, ionising ray-generating source, assembly comprising a plurality of sources and method for producing the source|
    CN201880045808.8A| CN110870036A|2017-07-11|2018-07-11|Compact ionizing radiation generating source, assembly comprising a plurality of sources and method for producing the source|
    KR1020207000373A| KR20200024211A|2017-07-11|2018-07-11|Compact ionizing radiation generating source, assembly comprising a plurality of sources and method of manufacturing the source|
    IL271796A| IL271796D0|2017-07-11|2020-01-01|Compact source for generating ionizing radiation, assembly comprising a plurality of sources and process for producing the source|
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