X-ray tube with rotating tube shell and X-ray radiator with rotating tube shell

Abstract

The utility model relates to a rotary tube shell X-ray tube and a rotary tube shell X-ray radiator. The X-ray tube with the rotating tube shell is provided with a cathode, a vacuumized rotating tube shell and an anode, the rotating tube shell can be supported around a rotating axis at rotating frequency relative to a fixed supporting component, and the cathode and the anode are connected with the rotating tube shell in an anti-torsion mode. Wherein the cathode has a cathode head and an electron emitter which is inserted in the cathode head in a rotationally fixed manner, characterized in that the rotating shell is made of glass in a section between the anode and the cathode.

Description

Technical Field

[0001] The utility model relates to a rotating anode X-ray tube and a rotating anode X-ray radiator. Background Art

[0002] Conventional rotating anode X-ray radiators typically include a housing and a rotating anode X-ray tube, which is rotatably supported within the housing relative to the housing. For example, an X-ray radiator of this kind is known from DE 19 741 750 A1, which has a forced-cooled rotating anode and a rotating anode tube, the vacuum jacket of which rotates within a radiator housing filled with a liquid coolant.

[0003] Therefore, in conventional rotating anode X-ray radiators, typically the entire rotating anode X-ray tube, in particular the evacuated rotating anode, rotates together with the anode. In some rotating anode X-ray radiators, the cathode with the electron emitter is also torsionally connected to the rotating anode, so that the cathode, the anode and the rotating anode have the same rotation frequency. Other rotating anode X-ray radiators have a cathode with an electron emitter that is fixed in position and thus does not rotate together with the anode and the rotating anode, as described, for example, in DE 4 108 591 A1. In contrast, in a conventional rotating anode X-ray tube, only the rotating anode rotates relative to the evacuated tube housing.

[0004] Another difference between conventional rotating anode X-ray tubes and conventional rotating anode X-ray radiators relates to the placement of the electron emitter. In a conventional rotating anode X-ray tube, the electron emitter, which is fixed in position opposite the anode, is typically placed eccentrically outside the axis of rotation directly on the annular focal track of the anode. The focal track is generated, in particular, in such a way that the electrons arriving at the focal spot interact with the anode on an annular track due to the rotation of the anode. The electron emitter of such a rotating anode X-ray tube can have, for example, up to three different emitter elements, the electrons emitted by which can be geometrically focused to different focal spot sizes. The focusing is achieved, in particular, by means of a deflection unit, which generates an electric or electromagnetic field for this purpose.

[0005] In a conventional rotating anode X-ray tube, the electron emitter is typically centrally located above the anode on the axis of rotation. In order to keep the focal spot in a fixed position relative to the housing, the emitted electrons are typically deflected from the axis of rotation to the edge region of the anode by means of electromagnetic fields. For this purpose, the deflection unit has in particular a first quadrupole magnet which is configured to set the ratio of the length and width of the focal spot. When the deflection unit has a second quadrupole magnet, the size of the focal spot can typically be set using the second quadrupole magnet. The design of a rotating anode X-ray radiator having at least one quadrupole magnet is relatively complex and cost-intensive. SUMMARY OF THE UTILITY MODEL

[0006] The object underlying the present utility model is to provide a rotating anode X-ray radiator having a simpler and thus more cost-effective construction.

[0007] This object is achieved by the features of the independent claims. Advantageous designs are described in the dependent claims.

[0008] Regardless of the grammatical gender of specific terms, including persons with male or female gender identities.

[0009] A rotating anode X-ray tube according to the present utility model has:

[0010] - a cathode,

[0011] - a evacuated rotating housing which is rotatably supported about an axis of rotation with a rotational frequency relative to a fixed support member, and

[0012] - an anode,

[0013] wherein the cathode and the anode are torsionally connected to the rotating housing,

[0014] wherein the cathode has a cathode head and an electron emitter torsionally inserted into the cathode head,

[0015] characterized in that the rotating housing is made of glass in the section between the anode and the cathode.

[0016] The rotating housing made of glass as an embodiment in particular offers advantages directly resulting from the external shape of the rotating housing and thus of the rotating anode X-ray tube. The rotating anode X-ray tube according to the present utility model is particularly suitable as a relatively cost-effective embodiment.

[0017] Another advantage of the rotating housing is that glass is insulating, so that an optional deflection unit can be positioned closer to the glass envelope. The insulating properties of glass are also particularly advantageous since no other materials, such as ceramics which are traditionally used, have to be used for electrical insulation.

[0018] The rotating envelope, as a glass embodiment according to the present utility model, can in particular be referred to as a glass bulb. The glass bulb advantageously enables a relatively compact structural form, which does not require a waist compared to conventional rotating envelope X-ray radiators. Thus, the minimum length of the rotating envelope is particularly preset by the insulation length required between the anode and the cathode. Therefore, the deflection of the emitted electrons by means of the deflection unit can preferably be carried out directly from the cathode, while in conventional rotating envelope X-ray radiators, the deflection is carried out only after the waist.

[0019] In a rotating envelope X-ray tube, the cooling of the anode is direct cooling, where heat can be directly conducted from the anode to a cooling medium flowing around the rotating envelope, such as oil. Thus, the temporary storage of heat in an intermediate heat storage, which is thermally coupled to the anode and is typically made of graphite, can be advantageously omitted. Therefore, preferably, the maximum thermal load of the anode is relatively very large with respect to the size of the anode and the heat capacity somewhat related to this size.

[0020] A rotating envelope X-ray tube, in particular a rotating envelope, typically has a vacuum function. The rotating envelope is advantageously sealed airtight. The evacuated rotating envelope particularly includes a high vacuum.

[0021] The rotating envelope can be supported or is supported about a rotation axis, in particular by means of a support mechanism. The rotating envelope can in particular rotate about the rotation axis at a rotation frequency. The fixed support member can in particular be part of the support unit. The fixed support member is in particular part of a rotating envelope X-ray radiator and not part of the rotating envelope X-ray tube. In principle, it is conceivable that the entire support unit and thus the fixed support member are part of the rotating envelope X-ray tube.

[0022] The cathode head can alternatively in particular have a support mechanism, where the cathode head can be supported about the rotation axis by means of the support mechanism. The cathode head can in particular be supported with respect to the fixed support member. The fixed support member and optionally the support mechanism can be part of the support unit. The support unit can in particular be part of a rotary support and / or the cathode or part of the rotating envelope X-ray tube or part of the rotating envelope X-ray radiator. The support mechanism can be, for example, a rotor and / or a rotating support member. The fixed support member can in particular be a stator. The rotary support can in particular be a ball bearing or in particular a liquid metal bearing or a sliding bearing.

[0023] The support unit enables in particular the cathode head or the electron emitter or the rotating envelope to rotate at a rotation frequency. The rotation frequency is, for example, at least 5 Hz, in particular 50 Hz, preferably 200 Hz.

[0024] The cathode and the anode are typically arranged on opposite sides within a rotating envelope. There is a high vacuum, in particular, between the cathode and the anode. The anti-torsion connection of the cathode and the anode to the rotating envelope is realized, for example, by means of fastening means. The fastening means can in particular be soldered joints and / or welded joints. The anti-torsion connection of the cathode and the anode to the rotating envelope can alternatively or additionally be realized by means of components of a support unit such that the cathode and the anode are not directly coupled to the rotating envelope. The anode and the cathode, as well as the electron emitter and the rotating envelope, in particular rotate about the axis of rotation with the same rotational frequency.

[0025] The section made of glass between the anode and the cathode is in particular configured annularly and / or rotationally symmetrically with respect to the axis of rotation. The glass section extends in particular in the longitudinal direction of the rotating envelope over at least half the distance between the cathode and the anode. The glass section can extend in the longitudinal direction of the rotating envelope up to the height of the cathode or beyond the height of the cathode. Alternatively or additionally, the glass section can extend in the longitudinal direction of the rotating envelope up to a height in front of or behind the focal track on the anode. In the latter case, the glass section is in particular used as an X-ray exit window. The focal track in particular includes the focal spot on the anode where the emitted electrons impinge, and forms an annular focal track due to the rotation.

[0026] The cathode head typically has a circular external shape and can be configured as a focusing head. The external shape of the cathode head can alternatively be elliptical or polygonal.

[0027] The cathode head is supportable and is in particular similarly suitable for the electron emitter. In other words, the support means can be part of the electron emitter by means of which the electron emitter can be rotatably supported about the axis of rotation with a rotational frequency relative to a fixed support member. In particular, since the electron emitter is inserted into the cathode head in an anti-torsion manner, the support of the cathode head also means the support of the electron emitter and vice versa.

[0028] The electron emitter is in particular suitable for medical imaging. Alternatively or additionally, the electron emitter can be suitable for material inspection.

[0029] The electron emitter is typically fixedly connected to the cathode head and thus to the rotating envelope. The anti-torsion insertion in particular includes anti-torsion fastening. The electron emitter can in particular be inserted into the cathode head by means of fastening means. The fastening means can be screws and / or soldered joints and / or welded joints.

[0030] One embodiment proposes that the rotating tube housing is cylindrical in shape, and the first end side of the cylindrical rotating tube housing is configured to accommodate the support member on the cathode side, and the second end side of the cylindrical rotating tube housing is configured to accommodate the support member on the anode side, wherein the cathode is fastened to the support member on the cathode side, and the anode is fastened to the support member on the anode side, and wherein the support member on the cathode side and the support member on the anode side are configured to rotate the rotating tube housing relative to the fixed support member about the rotation axis. The cylindrical shape advantageously enables a compact rotating tube housing X-ray tube. The first end side and the second end side enclose the cylindrical rotating tube housing on opposite sides along the rotation axis. The central axis of the cylinder particularly corresponds to the rotation axis. The support member on the cathode side can be connected to the rotating tube housing in a vacuum-tight manner particularly at the first end side. The support member on the anode side can be connected to the rotating tube housing in a vacuum-tight manner particularly at the second end side. The support member on the cathode side and / or the support member on the anode side are typically part of a support unit, particularly a rotating support member and / or a rotor. The support member on the cathode side and / or the support member on the anode side can cooperate with the fixed support member particularly for the rotation of the rotating tube housing.

[0031] One embodiment proposes that the rotating tube housing is cylindrical in shape, and the entire side surface of the rotating tube housing is made of glass. In this case, the rotating tube housing can consist essentially of the side surface and / or only of glass. This embodiment is particularly advantageous in combination with the previous embodiments.

[0032] One embodiment proposes that the rotating tube housing X-ray tube is a bipolar high-voltage tube, wherein a negative high-voltage potential is applied at the cathode, and a positive high-voltage potential is applied at the anode. The difference between the positive high-voltage potential and the negative high-voltage potential particularly indicates the accelerating voltage, according to which electrons can be accelerated from the cathode towards the anode. Alternatively, it is conceivable that the cathode or the anode is at ground potential and only one of these two electrodes is at high voltage potential.

[0033] One embodiment proposes that the diameter of the rotating tube housing perpendicular to the rotation axis is less than 100 mm, preferably 85 mm or 65 mm. In this embodiment, the central axis of the rotating tube housing particularly corresponds to the rotation axis. The rotating tube housing is particularly constructed rotationally symmetrically with respect to the rotation axis. This structural form is advantageous due to its compactness.

[0034] One embodiment proposes that the length of the rotating tube housing along the rotation axis is less than 200 mm. In this embodiment, the central axis of the rotating tube housing particularly corresponds to the rotation axis. The rotating tube housing is particularly constructed rotationally symmetrically with respect to the rotation axis. Thereby, the structural form of the rotating tube housing X-ray tube can advantageously be smaller.

[0035] One embodiment provides that the rotary housing can be rotated about a rotation axis by means of a ball bearing. In this case, the support unit is a rotary bearing, which is configured as a ball bearing. The support unit can be stored in oil or in a vacuum. The support mechanism can in particular be the balls of the ball bearing.

[0036] Three different embodiments of the electron emitter are described below. The first embodiment relates to a non-segmented thermionic emitter. The second embodiment relates to a segmented emitter having a plurality of emitter elements. The third embodiment relates to a field-effect emitter having a segmented emitter surface.

[0037] One embodiment provides that the electron emitter includes a helical emitter having wire turns, wherein the wire turns of the helical emitter are configured flat such that the flat wire turns include a rectangular hollow core. This embodiment is particularly advantageous because cost advantages can thereby be achieved, in particular because the electron emitter is constructed relatively simply and is thus advantageous.

[0038] An alternative embodiment to the previous embodiment provides that the electron emitter has a segmented emitter surface, wherein the segmented emitter surface has a plurality of emitter pins and is configured to activate a subset of the segments of the segmented emitter surface as an active emission surface for field-effect emission of electrons from the active emission surface, wherein the active emission surfaces activated according to different subsets of the segments rotate pairwise about a rotation point.

[0039] Such a field-effect emitter can be particularly advantageous in that the segmented emitter surface is configured to activate a subset of the segments such that the active emission surfaces activated according to different subsets of the segments can rotate against the rotation direction of the rotary housing by an amount of the rotation frequency such that the active emission surface is substantially position-fixed relative to a fixed support member.

[0040] The electron emitter is particularly advantageous because the active emission surface is rotatable, whereby the electron emission is overall more flexible. The rotation of the active emission surface advantageously enables the reduction and / or omission of additional deflection processes by means of a deflection unit.

[0041] The segmented emitter surface is in particular a field-effect emitter surface. The field-effect emission is in particular carried out by applying a gate voltage to the carrier of the emitter surface, on which a plurality of field-effect emitter pins are provided. By means of the applied gate voltage, electrons are emitted in particular at the tips of the field-effect emitter pins. The field-effect emitter pins typically have carbon, silicon, and / or molybdenum.

[0042] Particularly in the case of a field effect emitter surface, the emitter surface may have a plurality of segments. Activation of only a part of such an emitter element, i.e., not all segments, can be carried out, for example, by exciting only a part of the emitter pins, so that only a part of the segments is excited for field effect emission. Exciting the emitter pins for field effect emission may be referred to as activating or switching on the corresponding segments using the emitter pins. Thus, the emitter surface can be divided into segments that can be activated independently of each other. The field effect emitter surface is in particular a so-called pixelated emitter surface. The segmentation of the field effect emitter surface is in particular Cartesian or rotationally symmetric segmentation.

[0043] The segmented emitter surface in particular has at least four segments arranged in a 2x2 matrix. Preferably, the emitter surface has at least nine or 100 segments. A number of segments greater than 256 or 1024 is also conceivable.

[0044] The outer shape of the segmented emitter surface can be rectangular, in particular square, or circular. In the latter case, the segmented emitter surface is in particular rotationally symmetric. The outer shape of the activated emission surface can deviate from the outer shape of the segmented emitter surface. For example, it is conceivable that the outer shape of the segmented emitter surface is square and the outer shape of the activated emission surface is circular or vice versa. Alternatively, it is conceivable that the outer shape of the activated emission surface is similar to or corresponds to the outer shape of the segmented emitter surface.

[0045] The segments of the emitter surface are in particular designed such that electron emission can be switched on or off via the activated emission surface of the segments. In the latter case, this means that the segments do not have an activated emission surface but a deactivated emission surface.

[0046] Activation or deactivation of the emission surface can be carried out clock-controlled and / or multiple times according to an emitter switch signal. The emitter switch signal can in particular be provided by a control unit. The emitter switch signal can in particular include switching on or off the gate voltage with respect to an activated subset of the segments.

[0047] The device for a segmented emitter surface for activating at least a subset of the segments in particular means that, for example, according to the emitter switch signal, the segmented emitter surface can be at least partially or completely activated or can be at least partially or completely activated. For example, the emitter switch signal can contain an indication of the segments to be activated or that are to be activated that form a subset and / or directly activate the segments based on electrical and / or physical connections.

[0048] The activated emission surface can include only activated segments. Alternatively, it is conceivable that the activated emission surface includes at least one deactivated segment.

[0049] The fact that the activated emission surface rotates pairwise about the rotation point by means of a change in the subset especially means that, during operation of the electron emitter, the activated emission surface can rotate and / or appear to be rotatable, since the emission surface can be activated successively and can be pairwise different from one another. In this context, the term "rotation" especially includes enclosing or twisting or tilting by an angle greater than zero.

[0050] In this connection, the rotation does not refer to a physical movement of the emitter surface itself in the direction of rotation. The fact that the activated emission surface is rotatable especially means that, with respect to the segmented emitter surface, the emission surface from which electrons are emitted is rotatable. The fact that the activated emission surface is rotatable especially includes activating at least one additional segment and / or deactivating at least one additional segment. Activation and deactivation can take place simultaneously.

[0051] Thus, it is advantageously feasible to rotate the electron emission from the segmented emitter surface over time. This especially means that the segmented emitter surface can operate in the manner of a propeller or a screw or the movement of a pointer, where the activated emission surface can rotate pairwise with respect to one another in each time unit. The fact that the subsets can be changed to rotate pairwise about the rotation point especially means that the first activated emission surface can be rotated compared to the second activated emission surface at a second moment, where the first moment is different from the second moment and the first activated emission surface is different from the broad emission surface. In particular, the subset of segments activated in the first activated emission surface is different from the subset of segments activated in the second activated emission surface.

[0052] The emission of electrons can be carried out by means of a method comprising the following steps:

[0053] - Receiving a rotation frequency signal,

[0054] - Activating different subsets of segments of the segmented emitter surface such that the activated emission surface rotates about the rotation point according to the received rotation frequency signal.

[0055] The rotation frequency signal is especially received by means of an interface, for example, by a control unit. For example, the rotation frequency signal is transmitted to the interface. Alternatively, the reception can be carried out within the control unit by a sub-control unit, where another sub-control unit within the control unit transmits the rotation frequency signal.

[0056] The rotation frequency signal especially describes and / or transmits the value of the rotation frequency. The rotation frequency signal can especially depend on the electron current and / or the acceleration voltage and / or the rotation frequency of the cathode. In particular, the rotation frequency signal can correspond to the rotation frequency of the cathode.

[0057] The rotation of the activated emission surface can in particular be carried out in accordance with a rotation frequency signal, which in particular means that the transformation frequency of at least a subset of its transformation sections is at least influenced by the rotation frequency signal or corresponds to the rotation frequency signal. In other words, advantageously, the transformation of the activated emission surface is carried out at a transformation frequency that corresponds to a particularly negative magnitude of the rotation frequency signal. The transformation of the activated emission surface is in particular carried out against the direction of rotation of the rotating envelope.

[0058] The rotation point is advantageously the center point of the segmented emitter surface. This embodiment is particularly advantageous because thereby the share of the available emitter surface can be increased, especially when the respective activated emission surfaces differ only in terms of their angle of rotation relative to the rotation point. Advantageously, each activated emission surface can essentially have the same shape and / or the same number of activated sections and / or the same size and / or the same electron flow.

[0059] The activated emission surfaces preferably overlap to the greatest extent possible. This embodiment advantageously ensures that the same subset of sections is not reactivated directly following one another. Generally, the activated emission surfaces overlap at the rotation point and / or around the rotation point. In this case, the activated emission surfaces in particular include the rotation point. In principle, alternatively, it is conceivable that, especially when the respective activated emission surfaces are arranged outside the rotation point, the activated emission surfaces do not overlap. In other words, in this case, the respective activated emission surfaces do not include the rotation point.

[0060] The activated emission surfaces typically form a circle by being stacked on top of each other. In this embodiment, typically a plurality of different moments are considered, at which a plurality of different subsets of the activated sections are present. This embodiment can typically be implemented independently of the external shape of the segmented emitter surface. The external shape of the segmented emitter surface can clearly be circular or square, while the external shape of the stacked emission surfaces is circular. The external shape of the stacked emission surfaces is in particular independent of the respective shape of the individually observed activated emission surfaces. Stacking on top of each other in particular means: adding up and / or being activated at least once during the operation of the electron emitter.

[0061] Advantageously, a cathode having a field effect electron emitter can be operated as follows: the activated emission surfaces activated according to different subsets of the sections rotate against the direction of rotation of the rotating envelope. Advantageously, by changing the subsets of the sections, the rotation of the cathode relative to the fixed support member can thereby be compensated, and thus the influence of the rotation can be reduced.

[0062] Particularly advantageously, the activated emission surface can rotate against the direction of rotation of the rotary envelope by an amount corresponding to the rotational frequency, such that the activated emission surface is substantially stationary relative to the fixed support member. Advantageously, by changing a subset of the said sections, it is thus possible to compensate for the rotation of the cathode relative to the fixed support member, such that the electron emission remains substantially stationary during rotation of the cathode. It can be said that the activated emission surface can rotate contrary to the rotation of the cathode head, such that the electron emission remains substantially stationary. The activated emission surface being substantially stationary relative to the fixed support member thus particularly means that, with respect to the coordinate system of the fixed support member, the extent and / or shape of the electron flow starting from the origin is substantially the same in the respective activated emission surface. In this context, stationary means static.

[0063] In the said context, substantially means that due to the dynamics during transformation of the activated emission surface and / or during activation and / or deactivation of the said sections and / or due to the physical interaction between the emitted electrons, marginal deviations in the extent and / or shape of the electron flow may occur. Preferably, the cathode is configured such that such deviations are minimal or non-existent.

[0064] The pivot point of the electron emitter is preferably located on the axis of rotation. This embodiment is particularly advantageous for use of the electron emitter in a rotary envelope X-ray tube.

[0065] Embodiments alternative to the previous field-effect electron emitter are described below.

[0066] The electron emitter has a segmented emitter surface, wherein the segmented emitter surface has at least two emitter elements that can be activated independently of one another, and is configured to activate at least one subset of the sections of the segmented emitter surface as the activated emission surface for emitting electrons from the activated emission surface, wherein the at least two emitter elements are arranged such that the segmented emitter surface is axially symmetrically formed in the emitter surface plane, wherein at least one of the at least two emitter elements is configured for thermionic emission of electrons, and wherein the at least two emitter elements are arranged close to one another such that the spacing between the respective emitter surfaces is minimal.

[0067] By arranging the plurality of emitter elements as close to one another as possible, it is advantageously possible to change the size of the focal spot associated with the extent of the activated emission surface in a cost-effective manner. In this case, preferably, the deflection unit, which usually requires a relatively more expensive quadrupole magnet, can be constructed less complexly, in particular without a quadrupole magnet, and thus more cost-effectively. The present utility model achieves another advantage in that in principle, field effect can be used - in combination with thermionic emitter elements or only using thermionic emitter elements. Due to its cost advantage, it is particularly advantageous to use emitter elements for thermionic emission.

[0068] The emitter surface of an electron emitter typically has at least as many segments as the emitter element part of the electron emitter. Thus, typically, an electron emitter has at least two segments.

[0069] Typically, one segment corresponds to each emitter surface. It is conceivable that, depending on the design of the emitter element and / or the emitter surface, an emitter surface includes more than one segment. In such a case, for example, the emitter surface can be divided into sub-regions that can be activated independently of each other. Thus, in principle, it is conceivable that an electron emitter with two electron emitters has an emitter surface with more than two segments.

[0070] The activatable emitter element is particularly designed such that electron emission can be switched on or off through the activated emission surface of the emitter element. In the latter case, this means that the emitter element does not have an activated emission surface but a deactivated emission surface. The activation or deactivation of the emission surface can be controlled continuously and / or multiple times according to an emitter switching signal. The emitter switching signal can be provided particularly by a control unit. The emitter switching signal can include, for example, switching on or off a thermionic heating current device connected upstream of the emitter element, switching on or off a high voltage at a grid connected downstream of the emitter element, and / or switching on or off the grid voltage of the emitter element.

[0071] The means for activating at least a subset of the segments of a segmented emitter surface particularly means that, for example, at least partially activates or can at least partially activate the segmented emitter surface according to the emitter switching signal. For example, the emitter switching signal can contain an indication of the segments to be activated or that are being activated that form the subset and / or directly activate the segments based on electrical and / or physical connections.

[0072] If the emitter element has more than one segment, the activated emission surface of the emitter element can include only the activated segments. Alternatively, it is conceivable that the activated emission surface includes at least one deactivated segment.

[0073] Axial symmetry in the emitter surface plane particularly means that the electron emitter includes at least one axis of symmetry. Depending on the design of the electron emitter, the axis of symmetry can be located within one emitter element or multiple emitter elements. Alternatively or additionally, the axis of symmetry can be located between two adjacent emitter elements.

[0074] The emission of electrons can typically be distinguished according to the physical effect on which the emission is based. In the case of thermionic emission, in particular, direct or indirect heating of the electron emitter is carried out, and the electron emitter emits electrons after reaching a minimum temperature. In the case of direct heating, in particular, the electron emitter itself is heated by means of a heating current, which is provided, for example, by a heating current device. In the case of indirect heating, another thermionic or non-thermionic emitter element is connected upstream of the thermionic emitter element, and the other thermionic or non-thermionic emitter element heats the thermionic emitter element together with the electrons emitted into the vacuum, and in the vacuum, free electrons are accelerated from the upstream-connected electron emitter towards the thermionic emitter. In this case, the heating current device is typically connected to the upstream-connected electron emitter to provide a heating current.

[0075] Field emission is carried out, in particular, by applying a gate voltage with respect to the carrier of the emitter element, on which a plurality of field emission emitter needles are provided. By the applied gate voltage, electrons are emitted, in particular, at the tips of the field emission emitter needles. The field emission emitter needles typically have carbon, silicon, and / or molybdenum.

[0076] In particular, in the field emission emitter element and / or in the indirectly heated thermionic emitter element, the emitter surface of such an emitter element can have a plurality of sections. Activation of only a part, i.e., not all sections, of such an emitter element can be carried out, for example, by exciting only a part of the emitter needles for field emission or by heating a defined area of only the indirectly heated electron emitter with free electrons.

[0077] The emitter elements are preferably arranged as close to each other as possible. The spacing between the corresponding emitter surfaces is advantageously small such that the emitter surfaces almost merge into each other. Typically, in any case, there is current isolation between the emitter surfaces. At least two emitter elements are arranged close to each other such that, in the case of simultaneous electron emission, the emitted electrons can be directly superimposed and / or cannot be distinguished. The emitter surfaces of the emitter elements are typically arranged and oriented such that the segmented emitter surfaces are in a plane and / or are flat.

[0078] The electron emitter can in particular assume different operating states in time. It is conceivable that the operating states are configured such that the corresponding emitter elements do not operate alternately. In other words, the activated emission surface does not change from one electron emitter to another over time. When emitter elements are additionally activated or deactivated, the activated emission surface typically only changes in terms of its extent. In an example with a total of two electron emitters, this means that theoretically four operating states are conventionally conceivable, namely that no emitter element is activated, that each one emitter element is activated, and that two emitter elements are activated. Preferably, the electron emitter according to the present invention is limited to three operating states, namely that no emitter element is activated, that one emitter element is activated, and that two emitter elements are activated.

[0079] One embodiment provides that the segmented emitter surface consists of two emitter elements and is substantially rotationally symmetric, wherein the first emitter element is formed annularly with a central opening, and wherein the second emitter element is arranged in the central opening within the first emitter element. This embodiment is particularly advantageous because the first emitter element, due to its annular shape, enables a rotationally symmetric electron emitter, which is particularly advantageous for a rotating anode X-ray tube. This embodiment advantageously enables two different extents at the activated emission surface, thus enabling two focal spot sizes. Substantially rotationally symmetric means that, apart from generally two supply sections to the first emitter element, which may be necessary for heating and / or maintaining the electron emitter, the first emitter element depicts a complete ring and / or circle. The emitter surface of the first emitter element and the emitter surface of the second emitter element are typically located in the emitter surface plane. The first emitter element is in particular bent around the central opening. The central opening in particular enables the second emitter element to be arranged in the central opening.

[0080] In particular, the first emitter element can be a helical emitter and thus configured for thermionic emission of electrons. Alternatively or additionally, the second emitter element can be configured for thermionic emission, for example configured as a helical emitter or a surface emitter. The second emitter element can alternatively be configured as a field effect emitter element. This embodiment in particular offers the advantage that a helical emitter can be formed annularly particularly simply.

[0081] One embodiment provides that the segmented emitter surface is composed of two emitter elements, which are configured symmetrically and rectangularly with respect to two mutually perpendicular spatial axes, and the height of the segmented emitter surface is greater than the width. Thus, the electron emitter has a total of two emitter elements that can be activated independently of each other. The respective emitter surfaces of these two electron emitters can be configured rectangularly, in particular square. In this embodiment, the electron emitter particularly includes two symmetry axes that are perpendicular to each other. One of these two symmetry axes is particularly located on the dividing line between the two emitter elements, where the width of the dividing line is preset by the spacing between the two emitter elements. The other symmetry axis of these two symmetry axes particularly extends centrally through the two emitter elements. The segmented emitter surface is particularly not square. In other words, the extended height of the emitter surface is greater than the width or the width is greater than the height, depending on the viewing angle of the emitter surface. This embodiment realizes an electron emitter with slightly asymmetrically mounted emitter elements and two focal spot sizes.

[0082] In particular, the first emitter element can be a helical emitter, and the second emitter element can be a helical emitter. This embodiment realizes a relatively cost-effective electron emitter.

[0083] One embodiment provides that the segmented emitter surface is composed of three emitter elements arranged side by side in a straight line and the height is greater than the width, and the emitter surface of one of the emitter elements is larger than the emitter surfaces of the other two emitter elements together. This straight line can particularly correspond to the symmetry axis. The emitter elements are particularly arranged in a row on the straight line. Preferably, the spacing between each two adjacent emitter elements is minimal. The segmented emitter surface is particularly rectangular, non-square, and / or the width is greater than the height. The relatively large emitter surface is typically arranged between the two small emitter surfaces. In one operating state, for example, all three emitter elements can be operated, and in another operating state, for example, only the emitter element with the relatively large emitter surface can be operated.

[0084] In particular, each emitter element can be a helical emitter and / or a surface emitter. Alternatively, the central emitter element can be a helical emitter and / or a surface emitter, and the emitter elements adjacent to the central emitter element are non-helical wire emitters. The non-helical emitter is particularly a hot electron emitter composed of a single wire. The wire emitter can particularly be straight. When the wire emitter is bent, the number of turns is usually less than 2, preferably less than 1. The helical emitter has at least 2 turns.

[0085] One embodiment proposes that two adjacent emitter elements are oriented relative to each other such that the longitudinal directions of the emitters are perpendicular to each other. In a helical emitter, the longitudinal direction of the emitter is in particular defined as the direction in which the windings are arranged in succession. In a linear emitter, the longitudinal direction of the emitter is defined as the direction of the longest extension of the line.

[0086] The rotating anode X-ray radiator according to the present invention has:

[0087] - a housing,

[0088] - a rotating anode X-ray tube, and

[0089] - a deflection unit,

[0090] wherein the rotating anode X-ray tube is rotatably supported in the housing about a rotation axis relative to the housing at a rotation frequency,

[0091] wherein the rotating anode X-ray tube has a cathode, a rotating anode and an anode,

[0092] wherein the anode is torsionally connected to the rotating anode within the rotating anode,

[0093] wherein the cathode has a cathode head and an electron emitter inserted into the cathode head for emitting electrons, and is arranged on the rotation axis within the rotating anode,

[0094] It is characterized in that the deflection unit is configured to generate a non-uniform field between the cathode and the anode within the rotating anode, wherein the non-uniform field affects the emitted electrons such that they are on different trajectories towards the anode, and is designed such that the path length differences of the emitted electrons along different trajectories within the non-uniform field are taken into account.

[0095] The rotating anode X-ray radiator is particularly advantageous because by using a deflection unit to generate a non-uniform field, the construction of the rotating anode X-ray radiator is substantially less complex and thus more cost-effective. The rotating anode X-ray radiator preferably does not include a separate bipolar / quadrupole magnet or other additional multipole magnets. According to the present invention, a non-uniform field is generated without using a bipolar / quadrupole magnet or other additional multipole magnets in order to deflect the electrons and at the same time focus the electrons in a suitable manner. Since the non-uniform field takes into account the path length differences of the emitted electrons, the need for complex deflection is preferably eliminated. Advantageously, the deflection unit achieves a uniform distribution in the electric focal spot, which is preferably accompanied by a uniform temperature distribution.

[0096] The housing typically completely surrounds the rotating anode X-ray tube and the deflection unit and / or is closed. The housing may have a cooling medium for cooling the rotating anode X-ray tube and / or the deflection unit. The cooling medium may be liquid and / or gaseous. The cooling medium is in particular air and / or oil. The housing may have a cooling device by which the cooling medium is tempered and / or replaced and / or circulated. The cooling device may have a heat exchanger and / or a cooling medium conveying section and a cooling medium discharge section. On the outer side of the housing, the surface of the housing can be increased, for example, by cooling fins.

[0097] The deflection unit generates a non-uniform field, in particular in a manner that conventionally requires quadrupole magnets. According to the present invention, compared with a conventional rotating anode X-ray radiator having quadrupole magnets, the deflection unit is simplified, whereby the deflection unit can be optimally set for relatively few operating points. Conversely, the deflection unit according to the present invention is thus technically less complex and does not require complex adjustment, and is thus more cost-effective.

[0098] The deflection unit preferably generates a non-uniform field in such a way that electrons can be fanned out and / or deflected in the radial direction, in particular taking into account the path length difference. The fanning out in the radial direction advantageously increases the length of the electric focal spot. The deflection in the radial direction in particular enables the electrons to reach a preset focal track. Another advantage of the radial deflection is that the width of the focal spot can be reduced, especially when the activated emission surface of the electron emitter is wider than the desired optical width.

[0099] The deflection unit in particular generates a field whose field strength is position-dependent. The deflection unit in particular generates such a non-uniform field in a volume section of the rotating anode located between the electron emitter and the anode. The volume section is in particular located between the activated emission surface and the focal track on the anode. It is conceivable that the volume section is not on a direct line of sight between the activated emission surface and the focal track, in particular due to the forces acting on the electrons, which are obtained from the generated non-uniform field. The deflection unit is in particular arranged and oriented such that the forces act on most of the emitted electrons, which are obtained from the generated non-uniform field. The deflection and / or fanning out of the electrons in the radial direction is in particular carried out by means of position-dependent forces.

[0100] The generation of a non-uniform field by the deflection unit may include generating a uniform field by the deflection unit in a further volume section. In principle, it is conceivable that in the volume section with a non-uniform field, a small part of the field strength is position-independent. This part is advantageously located outside the flight path of the electrons and / or acts on less than 50%, preferably less than 20%, of the emitted electrons. The deflection unit in particular aligns the orbits of the electrons such that most, advantageously at least 80%, of the electrons are affected by the non-uniform field. The deflection unit in particular aligns the orbits of the electrons such that most, advantageously at least 80%, of the electrons are affected by the non-uniform field.

[0101] The deflection unit in particular generates a non-uniform field, which is static during the emission period. The non-uniform field is in particular invariant during the emission period. The emission period in particular includes at least one pulse duration of the X-ray pulse.

[0102] The influence on the emitted electrons on their different orbits in particular means that, due to the non-uniform field, a force acts on the emitted electrons, which force may cause the deflection of at least one electron. Since the electron emitter is typically not a point-like electron source, but emits electrons from an activated emission surface within a specific, non-point-like extension with different starting positions, the emitted electrons typically have a spatial distribution perpendicular to the axis of rotation, which causes the emitted electrons to propagate on different orbits. The path length differences are in particular based on the different starting positions or spatial distributions of the respective electrons at the electron emitter. The propagation towards the anode is in particular effected by an acceleration unit, which in particular provides the high voltage between the cathode and the anode. In this context, the deflection of a plurality of electrons can in particular represent a movement and / or focusing and / or defocusing while maintaining their relative spacing from each other. During focusing or defocusing, at least one spacing between the electrons is changed by deflecting a plurality of electrons, in particular reduced during focusing and in particular increased during defocusing.

[0103] By fanning out and / or deflecting in the radial direction, the propagation of the emitted electrons typically takes place on a curved trajectory. The different orbits of the emitted electrons are typically curved according to the curved trajectory. From the curvature of the trajectory it follows that the electrons can pass through different path lengths along the respective orbits until the electrons interact with the anode in the focal spot. The path length differences resulting from the curvature of the trajectory along the different orbits of the electrons are advantageously taken into account by a design of the position-dependent forces of the non-uniform field. The non-uniform field can in particular be designed such that the electrons are subjected to different position-dependent forces according to their orbits.

[0104] It is conceivable that the non-uniform field is generated by the deflection unit according to the magnitude of the high voltage between the cathode and the anode. The non-uniform field can in particular be generated such that the spatial distribution of the electrons on the cathode side is different from the spatial distribution of the electrons on the anode side. The cathode side or the anode side in particular means after the electron emission at the cathode or before the electrons strike the anode. The difference in the spatial distribution between the cathode and the anode can lie in different extensions, in particular extensions perpendicular to the axis of rotation, preferably different widths and / or different lengths.

[0105] One embodiment provides that the deflection unit surrounds the rotary envelope in a plane perpendicular to the axis of rotation in a manner less than 360°, in particular less than 180°. In this case, the deflection unit does not completely surround the rotary envelope in the circumferential direction, in particular not to a large extent. Thus, this embodiment offers the advantage of a smaller space requirement for the deflection unit.

[0106] One embodiment provides that the inhomogeneous field is a magnetic field, and the deflection unit in particular has a coil with a magnetic core. In principle, it is conceivable that the deflection unit has a coil without a magnetic core. Alternatively, the deflection unit in particular only includes permanent magnets. The deflection unit in particular generates an inhomogeneous magnetic field by means of a coil with a magnetic core. The coil in particular has a current flowing through it and / or has a plurality of windings. The plurality of windings can be distributed on a single winding package or a plurality of winding packages. The magnetic field generated by the coil with a magnetic core is in particular static during the emission period. This embodiment is particularly advantageous because the inhomogeneous magnetic field is particularly suitable for taking into account the path length differences of electrons. The magnetic core typically has a soft magnetic material and / or ferrite or is a permanent magnet. In the case of the combination of the coil and the magnetic core, the inhomogeneous field is in particular jointly generated by the coil and the magnetic core. In this case, if the magnetic core is a permanent magnet, the coil current of the coil can be advantageously reduced because the permanent magnet can compensate for the smaller magnetic field of the coil. The magnetic core advantageously reduces the required coil current intensity for achieving the magnetic field. Alternatively or additionally, the magnetic core can affect the field gradient of the inhomogeneous field. Thereby, in particular, the deflection in length and / or width can be affected. Ideally, the higher torque of the magnetic field can be minimized by means of the magnetic core. Physically, the magnetic field typically has no effect in the direction of the (instantaneous) velocity of the electrons. Since the electrons essentially fly along the axis of rotation, the magnetic field is in particular inhomogeneous in a plane perpendicular to the axis of rotation.

[0107] It is conceivable that the coil includes a plurality of packages with windings, wherein the plurality of winding packages are arranged at angular sections of the magnetic core. In other words, in this embodiment, the central axis of the first winding package forms an angle other than 180° with the central axis of the second winding package, so that the two are not on the same straight line. The number of winding packages can in particular be two or three. The winding packages and the sections of the magnetic core can be arranged and configured symmetrically with respect to each other.

[0108] The magnetic core can in particular have a curved shape. The magnetic core is in particular not rod-shaped. The curved shape can in particular be C-shaped. The ends of the magnetic core can enclose an angle other than zero. This angle can in particular be equal to or less than 180°. This angle can in particular be between 90° and 180°.

[0109] Alternatively or additionally, at least one end or both ends of the magnetic core may be inclined. The inclination relates to the bending direction of the magnetic core in this context. In particular, when the closing surface forming the end of the magnetic core is perpendicular to the bending direction of the magnetic core, the magnetic core is not inclined. Thus, in particular, when the closing surface forming the end of the magnetic core forms an angle other than 90° with respect to the bending direction, there is an inclination.

[0110] The bent shape and / or the inclined ends particularly mean that the magnetic core is advantageously designed such that the share of magnetic field lines extending parallel outside the magnetic core is reduced. Thus, an inhomogeneous field is advantageously generated.

[0111] One embodiment provides that the magnetic core is oriented such that the ends of the magnetic core lie in the same plane perpendicular to the axis of rotation and are oriented equidistantly with respect to the axis of rotation. The ends of the magnetic core particularly lie at the same height with respect to the axis of rotation. The equidistant orientation particularly enables a symmetric orientation of the magnetic core about the axis of rotation.

[0112] One embodiment provides that the magnetic core is oriented such that the plane in which the ends of the magnetic core lie, which is perpendicular to the axis of rotation, intersects the axis of rotation between the cathode and the anode. This embodiment is particularly advantageous because the deflection unit is arranged relatively close to the electrons.

[0113] One embodiment provides that the magnetic core is oriented such that the central axis of the winding of the coil lies in the plane in which the ends of the magnetic core lie, which is perpendicular to the axis of rotation. In this case, in particular, the ends of the magnetic core and the central axis of the winding preferably lie at the same height with respect to the axis of rotation. Description of the Drawings

[0114] Below, the present utility model is described and explained in detail based on the embodiments shown in the drawings. In principle, in the following description of the drawings, structures and units that are substantially the same are named with the same reference numerals as when they first appear in the corresponding structures or units.

[0115] The drawings show:

[0116] Figure 1 showing a rotating anode X-ray tube according to the present utility model,

[0117] Figure 2 showing a variant of the rotating anode X-ray tube according to the present utility model,

[0118] Figure 3 showing a first embodiment of the electron emitter 10,

[0119] Figure 4 showing a second embodiment of the electron emitter,

[0120] Figure 5 showing a variant of the second embodiment of the electron emitter,

[0121] Figure 6 A cathode of a second embodiment with an electron emitter is shown,

[0122] Figure 7 Another view showing a cathode of a second embodiment with an electron emitter,

[0123] Figure 8 A third embodiment of an electron emitter is shown,

[0124] Figure 9 A variation of the third embodiment of the electron emitter is shown,

[0125] Figure 10 Another variation of the third embodiment of the electron emitter is shown.

[0126] Figure 11 The rotating tube shell X-ray radiator according to the utility model is shown.

[0127] Figure 12 shows a variant of the deflection unit,

[0128] Figure 13 Another variant of the deflection unit is shown,

[0129] Figure 14 A further variant of the deflection unit is shown.

[0130] Figure 15 A non-uniform field is shown. DETAILED DESCRIPTION

[0131] Figure 1 The rotating envelope X-ray tube 30 is shown in a longitudinal section along the axis A of rotation.

[0132] The rotating tube X-ray tube 30 has a cathode 20, a rotating shaft A and a rotating frequency relative to the cathode 20. Figure 1 The fixed support part (not shown) can support the evacuated rotating shell 31 and the anode 32. The cathode 30 and the anode 32 are connected to the rotating shell 31 in a rotationally fixed manner. The cathode 20 has a cathode head 21 and an electron emitter 10, which is inserted in a rotationally fixed manner into the cathode head 21. The rotating shell 31 is made of glass in the section 33 between the anode 32 and the cathode 20.

[0133] In addition, Figure 1As shown, the rotating envelope 31 is cylindrically configured. The first end side of the cylindrical rotating envelope 31 is configured to accommodate the support member 34 on the cathode side. The cathode 20 is fastened to the support member 34 on the cathode side. The second end side of the cylindrical rotating envelope 31 is configured to accommodate the support member 35 on the anode side. The anode 32 is fastened to the support member 35 on the anode side. The support member 34 on the cathode side and the support member 35 on the anode side are configured to rotate the rotating envelope 31 relative to a fixed support member (not shown in Figure 1 around the rotation axis A in the rotation direction R or against the rotation direction R. The support member 34 on the cathode side and the support member 35 on the anode side each have an axis that aligns with the rotation axis A. The axis rotates, for example, in the rotation direction R or against the rotation direction R, and the rest of the rotating envelope X-ray tube 30 rotates with the axis. The rotating envelope 31 can be rotatable around the rotation axis A by means of a ball bearing (not shown).

[0134] In the described embodiment, the entire side surface of the rotating envelope 31 is made of glass. The rotating envelope X-ray tube 30 is a bipolar high-voltage tube, where a negative high-voltage potential is applied at the cathode 20 and a positive high-voltage potential is applied at the anode 32.

[0135] In the described embodiment, the diameter of the rotating envelope 31 perpendicular to the rotation axis A is less than 100 mm and is 85 mm. The length of the rotating envelope 31 along the rotation axis A is less than 200 mm and is 156 mm. This length is suitable for insulating the glass envelope 30 between the cathode 20 and the anode 32 up to an accelerating voltage of 125 kV. For example, the negative high-voltage potential can be -62.5 kV, and the positive high-voltage potential can be 62.5 kV. The distance between the cathode 20 and the anode 32 is, for example, 90 mm, where the anode 32 has an anode angle of particularly 14°.

[0136] Figure 2 A variant of the rotating envelope X-ray tube 30 is shown in a longitudinal section along the rotation axis A. In this variant, the anode angle of the anode 32 is 16°, and the diameter of the rotating envelope 31 perpendicular to the rotation axis A is 65 mm.

[0137] Figure 3 A first embodiment of the electron emitter 10 is shown in a perspective view. The electron emitter 10 includes a helical emitter having wire turns. The wire turns of the helical emitter are flatly configured such that the flat wire turns include a rectangular hollow core. A particularly advantageous rectangular embodiment is the square embodiment shown.

[0138] Figure 4 A second embodiment of the electron emitter 10 for the rotating envelope X-ray tube 30 is shown in a top view.

[0139] The electron emitter 10 has a segmented emitter face 11. The segmented emitter face 11 has a plurality of emitter pins in a plurality of segments. Each segment typically includes at least one emitter pin.

[0140] For reasons of overview, the segmentation of the emitter face 11 is not shown in Figure 4 . The segmentation of the emitter face 11 can approximately be derived from the shown activated emission face 11.A, the boundaries of which run along the boundaries of the segments. Figure 4 The illustration in Figure 4 is schematic in this regard, since typically a segment is not formed infinitesimally small, i.e., includes only one punctiform emitter pin. It follows therefrom that the rod-shaped emission face 11.A has, for example, a serrated or ribbed edge in practice. As detailed above, in extreme cases, the number of segments can be four, and in the

[0141] shown embodiment, this number is, for example, 100 or more.

[0142] In Figure 4 it is also shown that the pivot point D is the center point of the segmented emitter face. The activated emission faces 11.A overlap maximally and form a circle on top of one another. Figure 4 Each activated emission face 11.A in

[0143] Figure 5 basically has the same rod shape, preferably the same number of activated segments, the same size and advantageously the same electron flow. Figure 4 shows an electron emitter 10 in an alternative embodiment. Instead of the circular outer shape as shown in

[0144] Figure 6 the segmented emitter face 11 has an angular outer shape. In this case, the segmented emitter face 11 has segments in the regions facing the corners that typically do not emit electrons.

[0145] The cathode 20 for a rotating anode X-ray tube 30 has a cathode head 21 and an electron emitter 10 according to Figure 4 and Figure 5 , which is inserted torsionally resistant into the cathode head 21.

[0146] In the described embodiment, the cathode head 21 and the electron emitter 10 have a circular outer shape. It is conceivable that the cathode head 21 in particular has a non-circular, but oval, outer shape. The cathode head 21 can be rotatably supported relative to a fixed support member about a rotation axis A at a rotation frequency. The rotation point D of the electron emitter 10 lies on the rotation axis A.

[0147] The segmented emitter surface 11 is configured to activate a subset of the segments such that the emission surface 11.A activated according to different subsets of the segments rotates against the rotation direction of the rotating envelope.

[0148] Figure 7 Shown in another view Figure 6 of the cathode 20.

[0149] Here, the cathode 20 is supported relative to Figure 7 a fixed support member not shown herein and rotates at a rotation frequency. The direction of rotation of the cathode head 21 together with the electron emitter 10 is indicated by a dashed arrow. The activated emission surface 11.A can rotate against the rotation direction of the rotating envelope by an amount of the rotation frequency such that the activated emission surface 11.A is substantially position-fixed relative to the fixed support member.

[0150] According to Figure 7 the described embodiment in, the activated emission surfaces 11.A appear to overlap each other and be position-fixed. In other words, the common rotation of the cathode head 21 with the inserted electron emitter 21 and the rotation of the activated emission surface 11.A cancel each other out.

[0151] Figure 8 The electron emitter 10 in the third embodiment is shown in a top view.

[0152] The electron emitter 10 is suitable for a rotating envelope X-ray tube 30. The electron emitter 10 has a segmented emitter surface 11. The segmented emitter surface 11 has at least two emitter elements 12.E, 12.1, 12.2 that can be activated independently of each other and is configured to activate at least one subset of the segments of the segmented emitter surface 11 as an activated emission surface 11.A for emitting electrons from the activated emission surface 11.A.

[0153] At least one of the at least two emitter elements 12.E, 12.1, 12.2, namely the emitter elements 12.1, 12.2, constitutes a thermionic emission for electrons. The at least two emitter elements 12.E, 12.1, 12.2 are arranged close to each other such that the spacing 12.A between the respective emitter surfaces is minimized.

[0154] At least two emitter elements 12.E, 12.1, 12.2 are arranged such that the segmented emitter surface 11 is formed axially symmetrically in the plane of the emitter surface and is substantially rotationally symmetric in the illustrated embodiment. With respect to Figure 1 the embodiment shown in

[0155] in the first embodiment, the segmented emitter surface 11 is formed by two emitter elements 12.1, 12.2. The first emitter element 12.1 is formed annularly with a central opening 12. The second emitter element 12.2 is arranged in the central opening 12.Z within the first emitter element 12.1. The shape of the central opening 12.Z is preset by the annular shape of the first emitter element 12.1.

[0156] The first emitter element 12.1 is a helical emitter. The second emitter element 12.2 can likewise be configured as a thermionic emitter element or as a field effect emitter element.

[0157] Figure 9 A variant of the electron emitter 10 of the third embodiment is shown. The variant differs from Figure 8 the variant of

[0158] in particular in the design of the emitter elements 12.E, 12.1, 12.2. The segmented emitter surface 11 formed by two emitter elements 12.1, 12.2 is formed axially symmetrically and rectangularly with respect to two mutually perpendicular spatial axes. The height of the segmented emitter surface 11 is greater than the width, in particular not square. The emitter elements 12.1, 12.2 are inserted into a circular cathode head 21.

[0159] Figure 10 Another variant of the electron emitter 10 of the third embodiment is shown.

[0160] The segmented emitter surface 11 is formed by three emitter elements 12.1, 12.2, 12.3 arranged side by side in a straight line and the height is greater than the width. The emitter surface of one of the emitter elements 12.1 of the emitter elements is larger than the emitter surfaces of the other two emitter elements 12.2, 12.3 together. For example, by additionally activating the other two emitter elements 12.2, 12.3, the focal spot generated by the activated emission surface of one electron emitter 12 can be increased. The segmented emitter surface 11 is formed axially symmetrically and, in the illustrated embodiment, rectangularly with respect to two mutually perpendicular spatial axes.

[0161] Figure 11 A longitudinal section through the rotating envelope X-ray radiator 40 is shown.

[0162] The rotating anode X-ray radiator 40 has a housing 41, a rotating anode X-ray tube 30, and a deflection unit 42. The rotating anode X-ray tube 30 is rotatably supported within the housing 41 about a rotation axis A at a rotation frequency relative to the housing 41. The rotating anode X-ray tube 30 has a cathode 20, a rotating anode 31, and an anode 32. The anode 32 is torsionally connected to the rotating anode 31. The cathode 20 has a cathode head 21 and an electron emitter 10 inserted into the cathode head 21 for emitting electrons, and is disposed on the rotation axis A within the rotating anode 31.

[0163] The deflection unit 42 is configured to generate a non-uniform field between the cathode 20 and the anode 32 within the rotating anode 31. The non-uniform field affects the emitted electrons such that they are on different trajectories towards the anode 32, and is designed such that the path length differences of the emitted electrons along different trajectories within the non-uniform field are taken into account. If the deflection unit 42 has a coil with a magnetic core, then Figure 11 in an example, the deflection unit 42 is designed such that a plane in which the ends of the magnetic core are located and which is perpendicular to the rotation axis A intersects the rotation axis A between the cathode 20 and the anode 31.

[0164] The rotating anode X-ray radiator 40 further has a fixed support member 43, which is torsionally connected to the housing 41. The fixed support member 43 particularly acts together with a cathode-side support member 34 and an anode-side support member 35 such that the rotating anode X-ray tube 30 can rotate relative to the housing 41.

[0165] Figure 12 Three views showing a variant form of the deflection unit 42 are presented. The deflection unit 42 surrounds the rotating anode 31 in a plane perpendicular to the rotation axis A by less than 360°, particularly less than 180°.

[0166] The deflection unit 42 has a coil with a magnetic core. The magnetic core is oriented such that the ends of the magnetic core are in the same plane perpendicular to the rotation axis A and are equidistantly oriented relative to the rotation axis A. The magnetic core is further oriented such that the central axis of the winding of the coil lies in the plane in which the ends of the magnetic core are located and which is perpendicular to the rotation axis A. Additionally, the magnetic core is designed such that the proportion of magnetic field lines extending parallel outside the magnetic core is reduced.

[0167] In the upper row, the two views show the deflection unit 42 together with the rotating anode 31, with the left side in a front view and the right side in a side view. In the lower row, a perspective view of the deflection unit 42 is shown.

[0168] Figure 13Another variant of the deflection unit 42 is shown in a detailed view. The non-uniform field is a magnetic field. The deflection unit 42 has a coil with a magnetic core. The magnetic core is curved and at least one end (in this embodiment, both ends) of the magnetic core is beveled.

[0169] Figure 14 Three views (front view, side view, perspective view from left to right) showing another variant of the deflection unit 42. The deflection unit 42 has a coil with a magnetic core. The coil includes a plurality of packages with windings. The plurality of winding packages are arranged at angled sections of the magnetic core.

[0170] Figure 15 A non-uniform magnetic field is shown. The deflection unit 42 has a coil with a magnetic core. The magnetic field components are schematically drawn, from which the drawn extension of the field lines shown along the solid lines is obtained. The non-uniform magnetic field configured in this way is particularly advantageous because Bx has a gradient in the negative y direction, and By has the sign of the x-axis and has a gradient in the y direction.

[0171] In addition, Figure 15 the position of the axis of rotation A is drawn purely exemplarily at the height of the x-axis. A movement of the axis of rotation A up or down along the y-axis can be easily envisaged.

[0172] Although the details of the present utility model have been described in detail and described by preferred embodiments, the present utility model is not limited by the disclosed examples, and other variant solutions can be derived by those skilled in the art without departing from the protection scope of the present utility model.

Claims

1. A rotating tube shell X-ray tube (30), the rotating tube shell X-ray tube having: - a cathode (20), - a evacuated rotating tubular housing (31) which can be supported at a rotational frequency about a rotation axis (A) relative to a fixed support member, and - an anode (32), The cathode (20) and the anode (32) are connected to the rotating tube shell (31) in a rotationally fixed manner. The cathode (20) comprises a cathode head (21) and an electron emitter (10) inserted into the cathode head (21) in a rotationally fixed manner. It is characterized in that The rotating tube shell (31) is made of glass in a section (33) between the anode (32) and the cathode (20).

2. The rotating tube housing X-ray tube (30) according to claim 1, It is characterized in that The rotating tube shell (31) is cylindrical in shape, and a first end side of the cylindrical rotating tube shell (31) is configured to accommodate a cathode-side support component (34), and a second end side of the cylindrical rotating tube shell (31) is configured to accommodate an anode-side support component (35), wherein the cathode (20) is fastened to the cathode-side support component (34), and the anode (32) is fastened to the anode-side support component (35), and wherein the cathode-side support component (34) and the anode-side support component (35) are configured to enable the rotating tube shell (31) to rotate around the rotation axis (A) relative to the fixed support component.

3. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The rotating housing (31) is cylindrical, and the entire side surface of the rotating housing (31) is made of glass.

4. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The rotating tube shell X-ray tube (30) is a bipolar high-voltage tube, in which a negative high-voltage potential is applied to the cathode (20) and a positive high-voltage potential is applied to the anode (32).

5. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The diameter of the rotating tube shell (31) perpendicular to the rotating axis (A) is less than 100 mm.

6. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The length of the rotating tube shell (31) along the rotating axis (A) is less than 200 mm.

7. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The rotating housing (31) is rotatable about the rotation axis (A) by means of a ball bearing.

8. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The electron emitter (10) comprises a spiral emitter with turns, wherein the turns of the spiral emitter are designed to be flat, so that the flat turns comprise a rectangular hollow core.

9. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The electron emitter (10) has a segmented emitter surface (11), wherein the segmented emitter surface (11) has a plurality of emitter needles and is configured to activate a subset of the segments of the segmented emitter surface (11) as an activated emission surface (11.A) for field effect emission of electrons in the activated emission surface (11.A), wherein the emission surfaces (11.A) activated according to different subsets of the segments rotate in pairs around a rotation point (D).

10. The rotating tube housing X-ray tube (30) according to claim 9, It is characterized in that The segmented transmitter surface (11) is configured to activate subsets of the segments, so that the transmitter surface (11.A) activated according to different subsets of the segments can rotate in the direction of rotation of the rotating tube shell at the value of the rotation frequency, so that the activated transmitter surface (11.A) is fixed in position relative to the fixed support component.

11. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The electron emitter (10) has a segmented emitter surface (11), wherein the segmented emitter surface (11) has at least two emitter elements (12.E, 12.1, 12.2) which can be activated independently of each other, and is configured to activate at least a subset of the segments of the segmented emitter surface (11) as an activated emission surface (11.A) for emitting electrons from the activated emission surface (11.A), wherein the at least two emitter elements (12.E, 12.1, 12.2) are arranged so that the segmented emitter surface (11) is designed axisymmetrically in the emitter surface plane, At least one of the at least two emitter elements (12.1, 12.2) is designed for thermionic emission of electrons, wherein the at least two emitter elements (12.E, 12.1, 12.2) are arranged close to one another such that a distance (12.A) between the respective emitter surfaces is minimized.

12. The rotating tube housing X-ray tube (30) according to claim 1 or 2, It is characterized in that The diameter of the rotating tube shell (31) perpendicular to the rotating axis (A) is 85 mm or 65 mm.

13. A rotating tube shell X-ray radiator (40), characterized in that: The rotating tube shell X-ray radiator (40) comprises: - a housing (41), - a fixed support member (43), and - A rotating envelope X-ray tube (30) according to any one of claims 1 to 12, The fixed bearing part (43) is connected to the housing (41) in a rotationally fixed manner, and the rotating tube housing X-ray tube (30) is supported in the housing (41) in a rotatable manner relative to the housing (41) by means of the fixed bearing part (43).

14. The rotating tube shell X-ray radiator (40) according to claim 13, It is characterized in that The rotating tube shell X-ray radiator (40) has a deflection unit (42), wherein the deflection unit (42) is configured to generate an inhomogeneous field between the cathode (20) and the anode (32) in the rotating tube shell (31), wherein the inhomogeneous field affects the emitted electrons to different orbits toward the anode (32), and is designed to take into account the path length differences of the emitted electrons along the different orbits in the inhomogeneous field.

15. The rotating tube shell X-ray radiator (40) according to claim 14, It is characterized in that The deflection unit (42) surrounds the rotating tube housing (31) by less than 360° in a plane perpendicular to the rotation axis (A).

16. The rotating tube shell X-ray radiator (40) according to claim 14 or 15, It is characterized in that The inhomogeneous field is a magnetic field, and the deflection unit (42) has a coil with a curved magnetic core.

17. The rotating tube shell X-ray radiator (40) according to claim 14, It is characterized in that The deflection unit (42) surrounds the rotating tube housing (31) by less than 180° in a plane perpendicular to the rotation axis (A).

Images