Improved cooling of a roentgen tube having anode heads

Abstract

The invention relates to a roentgen tube (1) comprising a source (4) for emitting electrons and an anode head (6) having a central axis (ZA), on an end side (10) of which a target (11) is formed onto which the electrons impinge in an excited region (9) in operation, the anode head (6) providing a flow path (16) for a cooling fluid, which flow path leads from at least one inlet connection (14a) via a radially outer section (20), further via a cooling gap (21) and further via a radially inner section (22) to at least one outlet connection, characterized in that the excited region of the target (11) is formed substantially ring-shaped and in that the local height (H1, H2) of the cooling gap in a region (26) of the anode head opposite the excited region of the target continuously increases from radially outside to radially inside. The roentgen tube according to the invention can be operated with higher power and / or with lower wear.

Description

Technical Field

[0001] The present invention relates to a Röntgen ray tube comprising a source for releasing electrons and an anode head having a central axis, wherein a target is formed on the end side of the anode head, and electrons strike the target in an excited region during operation, wherein the anode head provides a flow path for cooling fluid, the flow path extending from at least one inlet connection via a radially outer section, further via a cooling gap and further via a radially inner section to at least one outlet connection. Background Technology

[0002] Such a Röntgen ray tube is known from the document EP 4 141 905 A1.

[0003] X-rays are used in a wide variety of ways to examine the chemical and physical properties of all types of samples and objects. For example, X-ray fluorescence can be used to qualitatively and quantitatively determine the atomic composition of a sample. Furthermore, X-rays can penetrate into the interior of an object and pass through it without damaging it. This allows for the determination of the composition within the object.

[0004] In many cases, it is desirable to use high-intensity X-rays in order to achieve more accurate and / or faster X-ray measurements.

[0005] X-rays are typically produced by a X-ray tube as described above. A source for releasing electrons, such as a (spiral) filament, is placed in a vacuum region of the X-ray tube. The source is connected as a cathode. A target, connected as an anode, is further placed in the vacuum region. The target can be made of, for example, copper, rhodium, chromium, molybdenum, or silver. Electrons from the source are accelerated towards the target by an electric field and collide there. The colliding electrons are braked, generating brake radiation. Furthermore, the colliding electrons knock other electrons out of the atoms of the target material; if these fill the free electron shells, then the characteristic X-rays are generated. The electrons colliding with the target intensely heat the target, thus requiring active cooling of the target in most cases. If the target becomes too hot, it may melt, thereby destroying the X-ray tube. In practice, the cooling of the target often limits the power of the X-ray tube.

[0006] A Röntgen ray tube is known from EP 4 141 905 A1, in which a substantially cylindrical anode head within a cathode housing forms a target on its end side. Electrons released from a hot cathode within the cathode housing are accelerated onto the target. An inlet conduit for coolant is connected to a first channel in the anode head, comprising an inclined extension and a subsequent extension along the central axis of the anode head. The first channel leads to a cooling gap beneath the target, perpendicular to the central axis of the anode head and having a uniform height. The cooling gap transitions into an annular channel radially outward within the anode head. A second channel for coolant is diverted from the annular channel, to which a return conduit is connected. Coolant (water) flows axially through the first channel, radially inward through the cooling gap, and axially back into the second channel in the annular gap to cool the target or the anode head as a whole. Alternatively, the water flow can be reversed.

[0007] The structure described herein can provide a X-ray tube with sufficient X-ray power for multiple purposes.

[0008] Based on the thermal power of the electrons striking the target, water can partially evaporate below the target in the cooling gap, forming boiling bubbles. It has been noted that while boiling bubbles (i.e., water vapor) can absorb significant heat during their formation through the phase transition in the evaporation phase, the water vapor in the boiling bubbles absorbs and carries away significantly less heat than liquid water. If the boiling bubbles are not carried away quickly enough, the cooling power at the anode head decreases drastically, and the target may melt.

[0009] Furthermore, the boiling bubbles that are generated can collapse shortly after their formation (a phenomenon known as cavitation), leading to mechanical stress on the surrounding material. While cavitation does not affect cooling power, it does increase wear on the anode tip.

[0010] The power of the Röntgen tube, as known from EP 4 141 905 A1, is thus chosen to avoid target melting and to keep wear due to cavitation within an acceptable range.

[0011] A Röntgen ray tube is known from DE 10 2017 216 059 A1, in which the target is set on a solid, raised substrate.

[0012] US 2021 / 0249214 A1 describes a Röntgen ray tube comprising cooling by a cooling fluid that flows in a structural form through an intermediate pre-flow chamber into an annular radially outer return chamber via a curved gap beneath a target. The curved gap has a constant width.

[0013] A Röntgen ray tube is known from DE 10 2016 000 033 B4, which has a target at the inlet end of a carrier. The carrier is connected to a cooling unit located radially outside via a connector, a heat outlet, and an insulating material region; the cooling unit may be water-cooled. Summary of the Invention

[0014] The object of this invention is to provide a X-ray tube that can operate with higher power and / or lower wear.

[0015] The objective is achieved according to the invention by a Roentgen ray tube of the type described at the beginning, characterized in that the excited region of the target is substantially annular, and in the region of the anode head opposite the excited region of the target, the local height of the cooling gap continuously increases from the radial outside to the radial inside.

[0016] Improved cooling can be achieved using the X-ray tube according to the invention. Based on the improved cooling, the X-ray tube can be operated at a higher X-ray power, or it can be operated with less wear and therefore a longer lifespan at the same X-ray power.

[0017] In the X-ray tube according to the invention, the cooling fluid flows radially from the outside to the inside within a cooling gap based on designated connections (inlet and outlet connections). Boiling bubbles are formed within the cooling gap during operation. A significant cooling effect is achieved through the generation of these boiling bubbles (more precisely, through a phase inversion from liquid water to water vapor, or correspondingly for other cooling fluids). The increased height of the cooling gap along the flow direction of the cooling fluid improves the removal of boiling bubbles from the cooling gap. Furthermore, a large number of boiling bubbles can then be reliably and rapidly flushed out with cooling water. Correspondingly, good heat dissipation can be ensured even at higher X-ray power (and thus for higher heat loads on the target). Therefore, the X-ray tube according to the invention can operate at higher power compared to conventional X-ray tubes.

[0018] By allowing the cooling fluid to flow from the outside in, even as the height of the cooling gap increases along the flow direction, the cross-sectional area of ​​the flow path can remain relatively small along the flow direction. In contrast, when the flow direction is from the inside out, and the height of the flow path increases along the flow direction, the cross-sectional area must necessarily increase significantly. By keeping the cross-sectional area relatively small along the flow direction, the pressure in the coolant can be maintained at a high level, particularly within the cooling gap, where the pressure remains the same or even increases along the flow direction. This prevents the collapse (or cavitation) of boiling bubbles in or near the cooling gap. Consequently, less wear is achieved in the anode head.

[0019] The excited region of the target is substantially annular. In the opposite region of the anode head (i.e., below or after the excited region), a cooling gap can then be established with a height that increases along the flow direction, thereby effectively removing boiling bubbles. The center of the anode head's end side remains free from direct electron impact, thus the center is not heated so intensely, and no or, if necessary, a small amount of boiling bubbles are generated in the adjacent portion of the flow path. Typically, the plunger portion is opposite the center of the end side (see below).

[0020] The local height of the cooling gap can be measured along the wall toward the target, perpendicular to the cooling gap (ignoring possible microscopic waviness of the wall toward the target). This direction largely corresponds to the axial direction (the direction of the central axis of the anode head).

[0021] The end face is typically oriented at least substantially perpendicular to the central axis of the anode head. The central axis is typically concentric with the annular excited region. Typically, the external configuration of the anode head is configured to be rotationally symmetrical about the central axis, at least in the regions of the end face and the surrounding sidewalls. The anode head may, in particular, have a substantially cylindrical external shape.

[0022] The region in which the local height of the cooling gap increases radially from the outer to the inner side typically includes at least 15%, preferably at least 20%, and particularly preferably at least 25% of the radius of the anode head.

[0023] Preferred embodiments of the present invention

[0024] One preferred embodiment of the Röntgen ray tube according to the invention is wherein the local cross-sectional area of ​​the cooling gap continuously decreases radially from the outer to the inner region in the region of the anode head opposite the excited region of the target, remaining constant or continuously increasing by a maximum of 15%. The pressure in the cooling fluid can be maintained or increased by the reduced cross-sectional area along the flow direction in the cooling gap, particularly in the region further radially inward of the cooling gap. The average flow velocity of the cooling fluid then remains constant or increases radially inward in the cooling gap. This suppresses cavitation and reduces macroscopic recirculation. Typically, the reduction in cross-sectional area is approximately 5-20% in total. Because the volume of the cooling fluid increases along the flow path in the flow direction (i.e., radially inward in the cooling gap) due to boiling bubble formation and thermal expansion, maintaining the same cross-sectional area or a slight increase in cross-sectional area is acceptable without resulting in enhanced cavitation. Lower cavitation improves the durability of the Röntgen ray tube. Less recirculation improves cooling efficiency. The local cross-sectional area can be measured as a sub-surface of a conical or cylindrical circumferential surface, wherein the circumferential surface is oriented along a direction perpendicular to the cooling gap toward the target wall (ignoring possible micro-wavelengths of the target wall). This direction largely corresponds to the axial direction.

[0025] One advantageous embodiment involves a continuous decrease in the local cross-sectional area of ​​the cooling gap in the region of the anode head opposite the excited region of the target, from the radially outer to the radially inner side, particularly a continuous decrease of up to 20%. This reduced cross-sectional area ensures that the pressure in the cooling fluid always increases from the outside to the inside along the flow path in the region of the cooling gap (i.e., even if there should be no or only a small amount of boiling bubble formation and / or the thermal expansion effect should be minimal), and correspondingly, cavitation is minimized. If the reduction in cross-sectional area is 20% or less, and the corresponding flow velocity of the cooling fluid does not increase significantly, then mechanical flushing of the anode head material is suppressed.

[0026] One preferred embodiment is in which the flow path in the anode head is configured to be at least substantially rotationally symmetrical about the central axis. This allows for particularly uniform cooling of the excited region of the target. It is noted that the flow path is typically not perfectly rotationally symmetrical. In particular, deviations can exist in the regions of the outer segments of the flow path through distribution structures in radially spaced, rotationally symmetrical sections, or in the transitions to the inlet or outlet connections. In the regions of rectifier elements, rotational symmetry with multiples (mostly high, e.g., 8 or higher) about the central axis is typical, and in the regions of swirling elements, rotational translational symmetry (e.g., twisting, with the central axis as the helical axis) or rotational symmetry with multiples (mostly high, e.g., 8 or higher) about the central axis can exist. Such deviations are still considered to be consistent with a substantially rotationally symmetrical flow path.

[0027] One advantageous embodiment is that the radially outer section of the flow path forms at least substantially around the entire circumference of the anode head. This contributes to particularly uniform cooling of the excited region of the target. Preferably, the flow path forms completely around the entire circumference of the anode head in the radially outer section.

[0028] One particularly preferred embodiment involves a distribution structure formed in the radially outer section of the flow path, which allows the cooling fluid flow to be distributed and homogenized circumferentially around the anode head from at least one inlet connection to the cooling gap. This achieves particularly uniform and effective cooling of the excited region of the target. The distribution structure may, in particular, consist of multiple axially and azimuthally spaced blades or guide plates.

[0029] An improvement to this embodiment is advantageous in that the distribution structure, in the radially outer section near the target sub-section, includes a set of rectifying elements for the cooling fluid distributed circumferentially around the anode head. These rectifying elements extend between the annular gap on the inlet side and the annular gap or cooling gap on the outlet side. Using these rectifying elements, at least substantially parallel sub-flows of cooling fluid can be established and separated from each other. The rectifying elements achieve the following: the fluid flow that initially flows in circumferentially is distributed circumferentially to axial sub-flows and cannot continue axially without deflection in its position. In particular, vortices previously introduced into the fluid flow can be eliminated or at least minimized in the synthesized fluid flow. The annular gap preceding the set of rectifying elements (“inlet side”) and—wherever they exist—following the set of rectifying elements along the flow direction (“outlet side”) each constitute a homogenization region. The cooling gap is typically connected to the annular gap on the outlet side. Sub-flows that are at least substantially parallel typically have an intermediate angle of 20° or less, mostly 10° or less (with respect to the average flow direction in the respective sub-flow).

[0030] Another advantageous improvement to the above embodiment is that the distribution structure includes a set of rectifying elements for the cooling fluid distributed circumferentially around the anode head in the radially outer section of the flow path, away from the target. These rectifying elements extend between annular gaps on the inlet and outlet sides, and allow the establishment and separation of at least substantially parallel sub-flows of the cooling fluid. The rectifying elements also achieve the following: fluid flows that partially flow in the circumference are distributed circumferentially to axial sub-flows and cannot continue axially without deflection in their position. In particular, swirls previously introduced into the fluid flow can be eliminated or at least minimized in the combined fluid flow. Typically, at least one inlet connection opens into the annular gap on the inlet side of the rectifying element for the target-away sub-section; alternatively, cooling fluid flows with swirls can also flow into the annular gap on the inlet side from an upstream swirling element. Sub-flows that are at least substantially parallel typically have an intermediate angle of 20° or less, mostly 10° or less (with respect to the average flow direction in the respective sub-flow).

[0031] Advantageously, another variation is provided where groups of rectifier elements are provided not only in the radially outer section of the flow path near the target but also in the section far from the target (or further away from the target). The annular gap between the rectifier elements in the section far from the target and the rectifier elements in the section near the target on the outflow side is simultaneously the annular gap between the rectifier elements in the section near the target and the rectifier elements in the section far from the target on the inflow side. Furthermore, the group of rectifier elements in the section near the target is offset from the group of rectifier elements in the section far from the target relative to each other in the azimuth direction about the central axis of the anode head. This results in minimal deflection being introduced into the coolant flow in the intermediate annular gap, and achieves particularly good uniformity of cooling power in the azimuth direction.

[0032] The following sub-variant is also preferred, wherein the rectifier element is oriented at least substantially axially, and correspondingly the sub-flow of cooling fluid is oriented at least substantially axially. This configuration is simple in structure and reliably minimizes swirl in the cooling fluid. Typically, the deviation from the accurate axial orientation is at most 10°, mostly at most 5°, or even 0°.

[0033] In a preferred sub-variant configuration, the rectifier element is at least partially composed of the following components:

[0034] - Parallel blades, especially blades that are straight (linearly) parallel, and / or

[0035] - Trapezoidal or triangular blades, and / or

[0036] - Leaflets shaped like droplets or rhombuses

[0037] The blades are formed on the radially outward-oriented and / or radially inward-oriented wall sides of the anode head, wherein the radially outward-oriented and radially inward-oriented wall sides together define the radially outer section of the flow path. This structural form has been proven in practice and can be manufactured relatively simply.

[0038] Furthermore, the following sub-flow variation is advantageous, wherein the rectifier element is at least partially composed of multiple parallel hollow structures arranged in the radially outer segment of the flow path, particularly where the multiple parallel hollow structures form a honeycomb structure. The hollow structures are structurally simple to construct. The honeycomb structure allows for particularly tight packing of the hollow structures and enables the creation of a particularly large cross-sectional area for the sub-flow.

[0039] In an advantageous improvement, the distribution structure includes one or more swirling elements in a target-remote sub-section of the radially outer portion of the flow path. These swirling elements are disposed between at least one inlet connection and an annular gap on the outlet side, and the swirling elements introduce swirling flow about the central axis into the cooling fluid flow. The swirling of the cooling fluid serves to uniformly distribute the cooling fluid (and the cooling fluid flow) circumferentially over the radially outer portion of the flow path. The swirling causes a velocity component of the cooling fluid in the circumferential direction of the anode head, thereby causing the cooling fluid to rotate about the anode axis. Typically, the target-remote sub-section where the swirling elements are located is also the target-remoteest sub-section of the radially outer portion of the flow path.

[0040] The following improvement to this embodiment is preferred, wherein at least one swirling element extends helically around the central axis of the anode head, thereby establishing at least one helical channel for the flow of cooling fluid. This structure has proven in practice and is well-suited for use even with high coolant flow rates, reliably introducing swirls into the coolant flow. The helical swirling element preferably rotates around the central axis at least 0.8 turns, particularly preferably at least 1.0 turns, and completely, particularly preferably at least 2.0 turns.

[0041] In a preferred improvement, multiple swirling elements extend helically around the central axis of the anode head, thereby establishing multiple helical channels for the sub-flows of cooling fluid that are azimuthally and / or axially staggered. The coolant flow can be distributed circumferentially through these multiple helical channels, each coolant flow having its own swirling flow, thus contributing to the uniform distribution of cooling power.

[0042] An improved embodiment with a distribution structure in the radially outer segment of the flow path is preferred, wherein a homogenization region for the cooling fluid flow is established between the distribution structure in the target-away sub-segment of the radially outer segment and the distribution structure in the target-approaching sub-segment of the radially outer segment, particularly wherein this homogenization region is established as an annular gap. The flow velocity of the cooling fluid can be homogenized in the homogenization region between the two (adjacent) sub-segments. In particular, the axial flow velocity (with respect to the flow direction of the cooling fluid) around the circumference after the homogenization region can have a smaller dispersion width compared to before the homogenization region. The homogenization regions can further be respectively set before the distribution structure in the target-away sub-segment and / or after the distribution structure in the target-approaching sub-segment of the radially outer segment of the flow path.

[0043] In a preferred embodiment, the anode head is configured to have a first flow element and a second flow element, which are interlocked and form at least a portion of a flow path therebetween. This is structurally simple and has been proven in practice.

[0044] A particularly preferred embodiment is one in which at least the radially inner section of the flow path, and if necessary, a cooling gap portion, is limited by a plunger portion extending into the interior of the anode head from its end side. In other words, the plunger portion extends from the target-facing wall of the flow path into the radially inner section of the flow path within the anode head. The plunger portion is typically located on the central axis. The plunger portion prevents cooling fluids converging from different radial directions from directly meeting (in the radial direction) in the transition region between the cooling gap and the radially inner section of the flow path. The plunger portion allows the cooling fluid to be redirected, particularly in the axial direction, and the cooling fluid flow can be made particularly approximately parallel. Furthermore, the plunger portion allows for the maintenance or regulation of the pressure distribution and flow velocity in the cooling fluid.

[0045] The X-ray tube arrangement also falls within the scope of this invention, comprising the X-ray tube as described above according to the invention and a cooling fluid supply device, wherein the supply device provides fresh cooling fluid at a delivery outlet connected to at least one inlet connection, and in particular, wherein the supply device further receives heated cooling fluid at a return inlet and the outlet connection is connected to the return inlet. Cooling fluid is supplied and typically also conveyed (e.g., pumped) using the supply device, and the flow of cooling fluid in the anode head is directed from the radial outside to the radial inside. The X-ray tube achieves particularly good cooling.

[0046] The application of the above-described Röntgen ray tube according to the present invention, or the above-described Röntgen ray tube arrangement structure according to the present invention, also falls within the scope of the present invention, wherein, during the operation of the Röntgen ray tube...

[0047] - Electrons are struck by a source used to release electrons into a ring-shaped excited region of the target, thereby producing X-rays, and

[0048] The cooling fluid flows radially from the outside to the inside within a cooling gap positioned opposite the excited region. Cooling is highly efficient through this cooling fluid within the cooling gap. Boiling bubbles contribute to heat absorption and are effectively carried away by the cooling gap, which rises along the flow direction. Simultaneously, cavitation is minimized.

[0049] In a preferred embodiment of the application according to the invention, the average flow velocity of the cooling fluid in the cooling gap placed in the excited region is maintained at the same level or increased from the radial outside to the radial inside, particularly by a maximum increase of 25%. This increased flow velocity ensures that the pressure in the cooling fluid does not decrease, and cavitation remains particularly low. Correspondingly, wear on the anode head is also minimal.

[0050] Further advantages of the invention arise from the specification and drawings. Similarly, the features described above and further elaborated can be applied individually or in any combination thereof according to the invention. The embodiments shown and described should not be construed as a final enumeration, but rather as exemplary features used in the description of the invention. Attached Figure Description

[0051] Detailed description of the present invention and the accompanying drawings.

[0052] Figure 1 A schematic longitudinal section is shown for an exemplary embodiment of the Röntgen ray tube according to the invention;

[0053] Figure 2a A schematic longitudinal section of an exemplary anode head according to a first structural form of the invention is shown, including a rectifier element in an upper sub-section close to the target in the radially outer section of the flow path and a swirling element in a lower sub-section away from the target.

[0054] Figure 2b Shown in Figure 2a On the plane BB Figure 2a A schematic cross-section of the anode head;

[0055] Figure 2c Shown in Figure 2a on the plane CC Figure 2a A schematic cross-section of the anode head;

[0056] Figure 2d Show Figure 2a A schematic top view of the anode head;

[0057] Figure 2e Show Figure 2a A schematic, semi-open perspective view of the anode head, including the internal flow elements;

[0058] Figure 2f Show Figure 2a A schematic, semi-open perspective view of the anode head, without internal flow elements;

[0059] Figure 2g Shown in the region near the end side Figure 2a A magnified view of the anode head;

[0060] Figure 3a A schematic longitudinal section of an exemplary anode head according to a second structural form of the invention is shown, including a rectifier element in an upper sub-section near the target in the radially outer section of the flow path and a rectifier element in a lower sub-section away from the target.

[0061] Figure 3b Shown in Figure 3a On the plane BB Figure 3a A schematic cross-section of the anode head;

[0062] Figure 3c Shown in Figure 3a on the plane CC Figure 3a A schematic cross-section of the anode head;

[0063] Figure 3d Shown in Figure 3a On the plane DD Figure 3a A schematic cross-section of the anode head;

[0064] Figure 3e Show Figure 3a A schematic, semi-open perspective view of the anode head, including the internal flow elements;

[0065] Figure 3f Show Figure 3a A schematic, semi-open perspective view of the anode head, without internal flow elements;

[0066] Figure 3g Shown in the region near the end side Figure 3a A magnified view of the anode head;

[0067] Figure 4a A schematic longitudinal section of an exemplary anode head according to a third structural form of the invention is shown, including a rectifier element in an upper sub-section near the target in the radially outer section of the flow path, a swirling element in a lower sub-section away from the target, and a rectifier element in an intermediate sub-section away from the target.

[0068] Figure 4b Shown in Figure 4a On the plane BB Figure 4a A schematic cross-section of the anode head;

[0069] Figure 4c Shown in Figure 4a on the plane CC Figure 4a A schematic cross-section of the anode head;

[0070] Figure 4d Shown in Figure 4a On the plane DD Figure 4a A schematic cross-section of the anode head;

[0071] Figure 4e Show Figure 4a A schematic, semi-open perspective view of the anode head, including the internal flow elements;

[0072] Figure 4f Show Figure 4a A schematic, semi-open perspective view of the anode head, without internal flow elements;

[0073] Figure 4g Shown in the region near the end side Figure 4a A magnified view of the anode head;

[0074] Figure 5 A schematic, semi-open side view of the anode head of the present invention is shown in the region of the radially outer segment of the flow path, including a helical swirling element and a droplet-shaped rectifying element.

[0075] Figure 6 A schematic, semi-open side view of the anode head of the present invention is shown in the region of the radially outer segment of the flow path, including a swirling element configured as inclined, extended blades and a trapezoidal rectifying element.

[0076] Figure 7 A schematic, semi-open side view of the anode head of the present invention is shown in the region of the radially outer segment of the flow path, including a hollow structure as a rectifier element and a trapezoidal rectifier element. Detailed Implementation

[0077] Figure 1 A schematic longitudinal section is shown of an exemplary embodiment of the Röntgen ray tube 1 according to the present invention.

[0078] In its Figure 1 In the upper part, the housing 2 (also called the cathode housing) surrounds the vacuum-sealed space 3. A source 4 for releasing electrons is provided in the vacuum-sealed space 3, which is constructed of a ring-shaped (spiral) filament. The (spiral) filament can be electrically heated via a connecting part 5. Furthermore, the anode head 6 extends into the vacuum-sealed space 3.

[0079] The source 4 is switched to a negative potential (compared to the anode head 6) via the connection part 5, i.e., it is switched to a cathode. The anode head 6 is switched to a positive potential (compared to the source 4) via the electrical connection part 7, i.e., it is switched to an anode. Electrons released at the source 4 are accelerated towards the anode head 6 through the potential difference between the source 4 and the anode head 6 and then through the vacuum space 3. Typically, the potential difference (also called the accelerating voltage) is between 1 kV and 100 kV.

[0080] By appropriately establishing the deflection of electrons 8 at a suitable potential, the flight trajectory of the electrons is thus established, such that the electrons are in the toroidal region 9 (in Figure 1 Midpoint marking, see also Figure 2d The particles impact the end side 10 of the anode head 6. A target 11 is formed on the end side 10 of the anode head 6. The target 11 is composed of an applied disk made of rhodium (or alternatively, copper, molybdenum, chromium, or silver, depending on the desired characteristic X-rays), which extends across the entire surface of the end side 10 of the plane.

[0081] Electrons that collide with the target 11 in the annular excited region 9 enter the material of the target 11 and are braked there. This generates X-rays in the form of braked radiation. Electrons are then ejected from the electron shells of the atoms in the material of the target 11. If these electron shells are then filled with electrons from higher shells, characteristic X-rays are generated. Most of the X-rays thus generated on the target 11 exit through the X-ray window 12 of the shell 2 and are then used for applications, such as X-ray fluorescence experiments (applications not further shown). The X-ray window 12 here is constructed of a beryllium disk.

[0082] The housing 2 and the anode head 6 are disposed on the isolator 13. The isolator 13 can be configured, for example, as in EP 4 141 905A1.

[0083] The anode head 6 is heated very strongly by electrons striking the target 11 during operation. Therefore, the anode head 6 is actively cooled with a cooling fluid. The cooling fluid can be, for example, water.

[0084] An inlet line 14 for fresh (cold) cooling fluid extends through an insulator 13 to the inlet connection 14a of the anode head 6. Furthermore, an outlet line 15 for the used (heated) cooling fluid extends from the outlet connection 15a of the anode head 6 through the insulator 13. Within the anode head 6, a flow path 16 for the cooling fluid extends from the inlet connection 14a to the outlet connection 15a (see, in particular, the flow path 16). Figures 2a-2g lower part).

[0085] The Röntgen ray tube 1 is connected to a cooling fluid supply device 17. Fresh cooling fluid is supplied from the supply device 17 at the delivery outlet 14b and fed into the anode head 6 via the inlet line 14. Heated cooling fluid flows from the anode head 6 to the return inlet 15b of the supply device 17 via the outlet line 15. The supply device 17 may include a cooling unit and a pump for the cooling fluid (not shown further). The entire assembly consisting of the Röntgen ray tube 1 and the connected cooling fluid supply device 17 is also referred to as the Röntgen ray tube arrangement structure 40.

[0086] Figures 2a to 2g An exemplary anode head 6 in the first structural form of the present invention is illustrated. Figure 2a The longitudinal section is shown, and Figure 2b and 2c The cross-sections at planes BB and CC are shown. Figure 2d A top view of the anode head 6 on the end side 10 of the anode head is shown. Figure 2e and 2f A partially open perspective view of the anode head 6 is shown, including the internal flow element 18. Figure 2e ) and without internal flow elements ( Figure 2f ). Figure 2g Finally, the region near the end 10 of the anode head 6 is shown. Figure 2a Enlarged view of the longitudinal section.

[0087] Figures 2a-2g The anode head 6 corresponds to Figure 1 (See also the anode head) Additionally, portions of the inlet line 14 and outlet line 15 for the coolant are also described; see [link to relevant documentation] for details. Figure 2a , 2e 2f. The coolant flows along the flow direction FR. In Figure 2d In the top view, the annular excitation region 9 of the target 11 is also clearly visible (the boundary is shown by dashed lines). The target 11 is perpendicular to the central axis ZA of the anode head 6. The anode head 6 is generally cylindrical in shape, with two small surrounding shoulders.

[0088] In the illustrated embodiment, the anode head 6 is composed of a first internal flow element (or sub-component) 18 and a second external flow element (or sub-component) 19. The flow elements 18 and 19 are nested and interlocked along the central axis ZA of the anode head 6. The second external flow element 19 here includes a cover 19a, which is located on and brazed or welded to the base 19b. A flow path 16 for cooling fluid is formed within the internal flow element 18 and between the flow elements 18 and 19. The flow path 16 extends from the inlet connection 14a via an inlet channel 14c (extending axially but off-center), a radially outer section 20, a cooling gap 21, a radially inner section 22 (extending axially and centrally), and an outlet channel 15c (inclined relative to the central axis) to the outlet connection 15a.

[0089] The radially outer section 20 extends between the radially outer side of the inner flow element 18 and the radially inner side of the outer flow element 19. The cooling gap 21 is located behind the annular excitation region 9 of the target 11 (in...). Figure 2g (Well visible in the middle). The cooling gap 21 is defined upward by the external flow element 19 and downward by the internal flow element 18. The cooling gap 21 extends substantially transversely to the central axis ZA. In the upper portion, the plunger portion 23 of the external flow element 19 extends into the radially inner section 22, thereby defining the radially inner section 22 in this upper portion by both the external flow element 19 and the internal flow element 18. In the lower portion of the radially inner section 22 of the flow path 16, only the radially inner flow element 18 defines the radially inner section 22. The axially radially inner section 22 transitions into the inclined discharge channel 15c.

[0090] The cooling fluid flows axially upward along the radially outer section in the flow path 16, flows from the radially outer to the radially inner region in the region of the cooling gap 21, and flows axially downward in the region of the radially inner section 22.

[0091] As in Figure 2g As can be clearly seen in the illustrated configuration, the upper wall 24 of the cooling gap 21 facing the target is perpendicular to the central axis ZA. The lower wall 25 of the cooling gap 21 facing away from the target extends straight but slightly inclined relative to the direction perpendicular to the central axis, wherein the wall 25 facing away from the target descends radially inward. In region 26 of the annular excitation region 9 placed on the target 11, the height of the cooling gap 21 (measured along the direction perpendicular to the wall 24 facing the target, i.e., along the axial direction) continuously increases from the radially outer to the radially inner (i.e., along the flow direction FR in the cooling gap 21). A first height H1 further radially outer and a second height H2 further radially inner are exemplarily depicted at the edges of region 26. The increasing height of the cooling gap 21 along the flow direction FR promotes the transport of boiling bubbles from the cooling gap 21 to the radially inner section 22 (and thus generally out of the anode head 6). Region 26—where the height of the cooling gap 21 continuously increases—extends at approximately 30% of the radius of the anode head 6 (in the axial position of the cooling gap 21).

[0092] Furthermore, in region 26, the cross-sectional area available for the cooling fluid in the cooling gap 21 also varies along the flow direction FR, i.e., from the radially outer to the radially inner side. This cross-sectional area corresponds here to the circumferential area of ​​the cylinder in the cooling gap 21, located at the corresponding radial position perpendicular to the upper wall 24 facing the target. For example, on the edge of region 26, a first area F1 further radially outer and a second area F2 further radially inner are marked in dots. It is noted that the cross-sectional area is calculated based on the product of the circumference and the height of the cooling gap at the corresponding radial position. In the embodiment shown, the cross-sectional area decreases slightly from the radially outer to the radially inner side, where approximately F2 = 0.8 * F1 (it is noted that in...). Figure 2g The radius decreases more rapidly inward than the height of the cooling gap, so that although the height increases, the cross-sectional area decreases radially inward. This reduction in cross-sectional area along the flow direction FR in the cooling gap 21 ensures that the pressure in the cooling fluid within the cooling gap 21 increases slightly radially inward; this prevents the collapse (cavitation) of boiling bubbles.

[0093] The plunger portion 23 deflects the cooling fluid flowing radially inward from the cooling gap 21 axially downward. Sub-flows of cooling fluid from different azimuth positions flow substantially parallel to each other in the axial direction after being deflected by the plunger portion 23, until they finally merge radially at the lower end of the plunger portion. This facilitates efficient flow of the cooling fluid.

[0094] In the illustrated structure, the radially outer segment 20 includes two sub-segments 27a and 27b, each constituting a distribution structure 28 for the cooling fluid. Annular gaps 29a, 29b, and 29c (also called annular channels) are provided before, between, and after the sub-segments 27a and 27b along the flow direction FR. In these annular gaps, the cooling fluid can diffuse throughout the entire circumference; no distribution structure is provided within the annular gaps. Utilizing the distribution structure 28 in the sub-segments 27a and 27b and the annular gaps 29a-29c acting as homogenization regions 32, the cooling fluid flowing into the anode head 6 via the respective inlet connections 14a and inlet channels 14c is distributed circumferentially around the anode head 6, thereby achieving substantially uniform coolant flow in the axial direction at all circumferential positions directly before the cooling gap 21.

[0095] Entering channel 14c—it is in Figure 2a The lower portion of the anode head 6 is formed near the right edge, opening into the lower annular gap 29a. This annular gap surrounds the entire circumference of the anode head 6. The lower annular gap 29a serves as a homogenization region 32 and does not contain any distribution structures.

[0096] A sub-section 27a, farther from the target, is connected to the lower annular gap 29a. In this embodiment, the first distribution structure 28, farther from the target, is provided with a helical swirling element 30, which is configured here on the radially outer side of the inner flow element 18, as in... Figure 2e The spiral swirling element 30 is clearly visible. It rotates approximately twice around the central axis ZA. The spiral swirling element 30 extends to the radially inner side of the outer flow element 19, thus forming a spiral channel 31 in the sub-section 27a away from the target (in the radial gap between flow elements 18 and 19). When flowing through the spiral channel 31, the cooling fluid acquires a velocity component in the circumferential direction around the central axis ZA.

[0097] A spiral channel 31 leads into the central annular gap 29b. The annular gap 29b also surrounds the entire circumference of the anode head 6. Furthermore, the central annular gap 29b acts as a homogenization region 32 and does not contain any distribution structures. The swirling flow introduced into the cooling fluid distributes the cooling fluid flow very evenly across the entire circumference of the anode head 6 within the annular gap 29b.

[0098] A sub-section 27b approaching the target is connected to the annular gap 29b in the middle. A set of rectifier elements 34 33 is provided in the sub-section 27b approaching the target (in the radial gap between flow elements 18 and 19). The rectifier element 34 is configured as a straight blade 34a extending parallel to the central axis ZA. The straight blade 34a is configured as a radially inwardly pointing protrusion on the radially inner side of the outer flow element 19, with the intermediate space as shown in… Figure 2f It is clearly visible in the middle. The swirling flow from the cooling fluid is removed by the rectifier element 34. The coolant flows axially upward in the section 27 near the target into the intermediate space 35 between the blades 34a.

[0099] An upper annular gap 29c is connected to the sub-section 27b near the target. An intermediate space 35 passes through this annular gap 29c. The annular gap 29c also surrounds the entire circumference of the anode head 6. Furthermore, this annular gap 29c also functions as a homogenization region 32 and does not contain any distribution structures.

[0100] The upper annular gap 29c transitions into the cooling gap 21 at its upper end. This is achieved through the distribution structure 28 in sections 27a and 27b, in conjunction with the homogenization region 32 (annular gaps 29a, 29b, 29c): the cooling fluid flows radially inward from all locations along the circumference of the anode head 6 at approximately the same speed into and through the cooling gap 21. This results in uniform cooling of the anode head 6, particularly in the (radial) region 26—which is opposite to and close to the excitation region 9 of the target 11.

[0101] Figures 3a to 3g An exemplary anode head 6 in the second structural form of the present invention is illustrated. Figure 3a The longitudinal section is shown, and Figure 3b , 3c Figure 3d shows the cross-sections at planes BB, CC, and DD. Figure 3e and 3f A half-open perspective view of the anode head 6 is shown, each including and without internal flow elements 18. Figure 3g Finally, the region near the end 10 of the anode head 6 is shown. Figure 3a An enlarged view of the longitudinal section. The second structural form is as similar as possible to... Figures 2a-2g The first structural form (particularly concerning the radial inner section 22 of the cooling channel 21 and the flow path 16) thus only clarifies the main differences (mainly in the region of the radial outer section 20 of the flow path 16) below.

[0102] A sub-section 27a, located away from the target, is connected to the lower annular gap 29a. A first set of rectifier elements 34 33a is provided in this sub-section. The rectifier elements 34 are configured as straight blades 34a extending parallel to the central axis ZA. The straight blades 34a are configured as radially inwardly pointing protrusions on the radially inner side of the outer flow element 19. Cooling fluid flows axially upward into the intermediate space 35 between the blades 34a in the section 27 near the target.

[0103] A central annular gap 29b is connected to the lower sub-section 27a, which is farther from the target. The annular gap 29b also surrounds the entire circumference of the anode head 6. The central annular gap 29b functions as a homogenization region 32.

[0104] A sub-section 27b approaching the target is connected to the annular gap 29b in the middle. A second set 33b of rectifier elements 34 is provided in this sub-section approaching the target. The rectifier elements 34 are also configured as straight blades 34a extending parallel to the central axis ZA. The straight blades 34a are configured as radially inwardly pointing protrusions on the radially inner side of the outer flow element 19, as in... Figure 3f The cooling fluid flows axially upward in the section 27b near the target into the intermediate space 35 between the blades 34a.

[0105] The second group of rectifier elements 33b is here staggered relative to the first group of rectifier elements 33a in the azimuth direction, as in... Figure 3c and 3d The intermediate space 35 in the second group 33b is clearly visible. The corresponding blades 34a in the first group 33a are aligned at their azimuth angles, and vice versa. This achieves the following: the sub-flow of cooling fluid from the intermediate space 35 in the first group 33a cannot travel in a straight (axial) direction into the intermediate space 35 of the second group 33b, but must be deflected laterally there. This lateral deflection is continued through the intermediate annular gap 29b.

[0106] An upper annular gap 29c is connected to the sub-section 27b near the target. The intermediate space 35 of the second group 33b passes through this annular gap 29c. The annular gap 29c also surrounds the entire circumference of the anode head 6. Moreover, this annular gap 29c functions as a homogenization region 32.

[0107] Figures 4a to 4g An exemplary anode head 6 in the third structural form of the present invention is illustrated. Figure 4a The longitudinal section is shown, and Figure 4b , 4c Figures 4d and 4d show the cross sections at planes BB, CC, and DD. Figure 4e and 4fA half-open perspective view of the anode head 6 is shown, each including and without internal flow elements 18. Figure 4g Finally, the region near the end 10 of the anode head 6 is shown. Figure 4a An enlarged view of the longitudinal section. The third structural form is as similar as possible to... Figures 2a-2g The first structural form, thus only the main differences will be explained below.

[0108] exist Figures 4a-4f In the structural form, the radial outer segment 20 of the flow path 16 includes three sub-segments: a lower sub-segment 27a that is farthest from the target (and the furthest from the target), a middle sub-segment 27c that is also far from the target, and an upper sub-segment 27b that is close to the target. The annular gaps 29a, 29b, 29c, and 29d are respectively located before sub-segment 27a, after sub-segment 27b, and between sub-segments 27a, 27b, and 27c, and each of them is simultaneously a homogenization region 32.

[0109] The lower annular gap 29a, the lower sub-section 27a away from the target, together with the spiral swirling element 30 serving as the distribution structure 28, and the immediately following middle annular gap 29b, are configured accordingly. Figures 2a-2g The structural form.

[0110] A middle sub-segment 27c is connected to the annular gap 29b in the middle. Because this middle sub-segment 27c is not the sub-segment that is closest to the target 11 in the axial direction, it is also considered to be far away from the target.

[0111] In the middle sub-section 27c, a first set of rectifier elements 34 33a is provided. The rectifier elements 34 are configured as straight blades 34a extending parallel to the central axis ZA. The straight blades 34a are configured as radially inwardly pointing protrusions on the radially inner side of the outer flow element 19, as in... Figure 4f The coolant flows axially upward in the intermediate sub-section 27c into the intermediate space 35 between the blades 34a.

[0112] Another intermediate annular gap 29d is connected to the intermediate sub-segment 27c. The annular gap 29d also surrounds the entire circumference of the anode head 6. The annular gap 29d functions as a homogenization region 32.

[0113] A sub-section 27b approaching the target is connected to the annular gap 29d in the middle. A second set 33b of rectifier elements 34 is provided in this sub-section approaching the target. The rectifier elements 34 are also configured as straight blades 34a extending parallel to the central axis ZA. The straight blades 34a are configured as radially inwardly pointing protrusions on the radially inner side of the outer flow element 19, as shown in... Figure 4fThe cooling fluid flows axially upward in the sub-section 27b near the target into the intermediate space 35 between the blades 34a.

[0114] The second group of rectifier elements 33b is here staggered relative to the first group of rectifier elements 33a in the azimuth direction, as in... Figure 4c and 4d The intermediate space 35 in the second group 33b is well visible. Aligned at the azimuth positions of the corresponding blades 34a in the first group 33a, the intermediate space 35 in the second group 33b is also present. This ensures that the sub-flow from the intermediate space 35 in the first group 33a cannot travel in a straight (axial) direction into the intermediate space 35 of the second group 33b, but must be deflected laterally there. This lateral deflection is continued through the intermediate annular gap 29b. It is noted that the blades 34a and the intermediate space 35 can have different widths along the azimuth direction.

[0115] An upper annular gap 29c is connected to the sub-section 27b near the target. The intermediate space 35 of the second group 33b passes through this annular gap 29c. The annular gap 29c also surrounds the entire circumference of the anode head 6. Moreover, this annular gap 29c functions as a homogenization region 32.

[0116] As in Figure 4g As can be clearly seen in the illustrated embodiment, the upper wall 24 of the cooling gap 21 facing the target is oriented at a slight inclination relative to the direction perpendicular to the central axis ZA, wherein the wall 24 facing the target descends radially inward. The lower wall 25 of the cooling gap 21 facing away from the target extends approximately linearly at a slightly stronger inclination relative to the direction perpendicular to the central axis ZA, wherein the wall 25 facing away from the target also descends radially inward. In region 26 of the annular excitation region 9 placed on the target 11, the height of the cooling gap 21 (measured along the direction perpendicular to the wall 24 facing the target, i.e., along the direction slightly inclination relative to the central axis ZA) increases from the radially outer to the radially inner (i.e., along the flow direction FR in the cooling gap 21). A first height H1 further radially outer and a second height H2 further radially inner are exemplarily depicted at the edge of region 26. This promotes the transport of boiling bubbles from the cooling gap 21 to the radially inner section 22.

[0117] Furthermore, in region 26, the cross-sectional area available for the coolant in the cooling gap 21 varies along the flow direction FR, i.e., from the radially outer to the radially inner side. This cross-sectional area corresponds here to the circumferential area of ​​the (circular) cone in the cooling gap 21, located at a corresponding radial position perpendicular to the upper wall 24 facing the target. For example, on the edge of region 26, a first area F1 further radially outer and a second area F2 further radially inner are marked in dots. The cross-sectional area in this structural configuration also decreases from the radially outer to the inner side, i.e., F2 < F1. The decreasing cross-sectional area along the flow direction FR in the cooling gap 21 ensures that the pressure in the cooling fluid increases slightly radially inward; this prevents the collapse (cavitation) of boiling bubbles.

[0118] Figure 5 Another exemplary structural form of the anode head 6 of the present invention is illustrated. Here, only a portion of the anode head 6 is shown in a highly schematic side view, which includes the radially outer segment of the flow path 16. The radially outer flow element 19 is cut off here and removed on the side facing the observer, so that the observer can see the internal flow element 18 and the distribution structure 28 (“semi-open” anode head 6) in the radially outer segment 20 of the flow path 16. This is illustrated relative to Figures 2a-2g The main difference in their structural forms.

[0119] In the lower section 27a, which is far from the target, there are a total of four helical swirling elements 30 (shown in dashed lines on the rear side of the radially inner flow element 18), through which a total of four helical channels 31 are established.

[0120] In the upper section 27b near the target, a flow-rectifying element 34, in the form of droplet-shaped blades 34b, is provided. All these blades are oriented axially (along the central axis ZA). The blades 34b are configured on the radially outward-oriented wall side 38 of the inner flow element 18 and extend into the radial gap 37 between the wall side 38 and the radially inward-oriented wall side 39 of the radially outer flow element 19. Alternatively, the blades 34b may also be configured on the wall side 39 (not shown further, but for this purpose see, for example, see...). Figure 2f The radial outer segment 20, which essentially forms the flow path 16, is formed by the radial gap 37.

[0121] Figure 6 This illustrates another exemplary structural form of the anode head 6 of the present invention, and further illustrates... Figure 5 This will be explained in a half-open view. This explanation is relative to... Figures 2a-2g The main difference in their structural forms.

[0122] In the lower section 27a, away from the target, a plurality of swirling elements 36 are provided, each configured as a single blade inclined relative to the central axis ZA. All swirling elements 36 have the same inclination position (“slope”) relative to the central axis ZA and are distributed along the circumferential and axial directions on the outer side of the radially inner flow element 18 in section 27a. It is noted that in other configurations, subsets of the swirling elements may be inclined differently (not shown further). Each single blade here spans only a small portion of the circumference (e.g., 1 / 10 or less of the circumference). The single blades are radially and axially spaced apart from each other.

[0123] In the upper section 27b near the target, a flow-rectifying element 34 with trapezoidal blades 34c is provided. All trapezoidal blades 34c are oriented axially (along the central axis ZA). However, the orientation of the trapezoidal blades 34c alternates, so that the thinner ends are alternately arranged in the upper and lower sections. Thus, the intermediate spaces 35 between each blade each have a slight inclination relative to the central axis ZA, wherein this inclination also alternates along the circumferential direction. Accordingly, the sub-flows of cooling fluid in adjacent intermediate spaces 35 are also slightly incised relative to each other (see also the flow direction FR regarding its average flow direction). This can contribute to better homogenization of the sub-flows of cooling fluid.

[0124] Figure 7 This illustrates another exemplary structural form of the anode head 6, and further illustrates... Figure 5 This will be explained in a half-open view. This explanation is relative to... Figures 3a-3g The main difference in their structural forms.

[0125] In the lower section 27a, away from the target, a plurality of rectifier elements 34 are provided, which are formed as hollow structures 34d in the form of small circular tubes. These tubes are all oriented parallel to the central axis ZA. The tubes completely fill the radial gap 37 between the inner flow element 18 and the outer flow element 19, here as a single layer of circular tubes or hollow structure 34d; the remaining space (“wedge”) is filled with resin (not shown further). Alternatively, the hollow structure 34d may also be configured, for example, as a honeycomb shape and fill the gap 37 (not shown further) with multiple layers typically honeycomb.

[0126] In the upper sub-section 27b near the target, the rectifier element 34 is configured as triangular blades 34e. All triangular blades 34e are axially oriented (along the central axis ZA) and have upward-pointing tips. Correspondingly, the intermediate space 35 is narrower at the bottom than at the top. This allows the pressure in the annular gap 29b preceding it to be maintained at a high level, which improves the homogenization of the cooling fluid flow.

[0127] List of reference numerals

[0128] 1 Roentgen ray tube

[0129] 2 shells

[0130] 3. Vacuum-enclosed space

[0131] 4. The source for releasing electrons, in this (spiral) filament.

[0132] 5. Electrical connection (of the cathode)

[0133] 6 anode heads

[0134] 7. Electrical connection (of the anode)

[0135] 8 deflection electrons

[0136] 9 (ring-shaped) excited region

[0137] 10. End side of the anode head

[0138] 11 targets

[0139] 12 rondo windows, here the beryllium plate

[0140] 13 isolation bodies

[0141] 14 Cooling fluid inlet piping

[0142] 14a Anode head inlet connection

[0143] 14b Conveying and Discharging Section

[0144] 14c Enter Channel

[0145] 15 Cooling fluid discharge piping

[0146] 15a anode head discharge connection

[0147] 15b Retraction into the entry section

[0148] 15c discharge channel

[0149] 16 Flow Paths

[0150] 17 Cooling fluid supply device

[0151] 18 Internal (First) Flow Element

[0152] 19 External (Second) Flow Element

[0153] 19a Cover of external flow element

[0154] 19b Base of external flow element

[0155] 20 Radial outer segment of the flow path

[0156] 21 Cooling gap

[0157] 22 Radial inner section of the flow path

[0158] 23 Plunger Section

[0159] 24. Cooling gap facing the target wall

[0160] 25 Cooling gap wall facing away from the target

[0161] 26. The region of the anode head is opposite to the excited region of the target.

[0162] 27a (lower) sub-section far from the target

[0163] 27b (upper) sub-section near the target

[0164] 27c (middle) sub-segment furthest from the target

[0165] 28. Allocation structure (general)

[0166] 29a-d Annular Gap

[0167] 30 spiral swirl element

[0168] 31 spiral channel

[0169] 32 homogenization region

[0170] 33 Rectifier Components Group

[0171] 33a First group of rectifier elements

[0172] 33b Second group of rectifier elements

[0173] 34 Rectifier Components (General)

[0174] 34a straight blades

[0175] 34b teardrop-shaped blade

[0176] 34c trapezoidal blades

[0177] 34d hollow structure (the small tube in this circle)

[0178] 34e triangular blade

[0179] 35 intermediate space

[0180] 36 swirl elements (single blades set at an angle)

[0181] 37 radial clearance

[0182] 38. Radially outward oriented wall side (on internal flow elements)

[0183] 39. Radially inward oriented wall side (on external flow elements)

[0184] 40 Roentgen ray tube arrangement structure

[0185] FR flow direction

[0186] ZA Central Axis

Claims

1. A Röntgen ray tube (1), comprising a source (4) for releasing electrons and an anode head (6) having a central axis (ZA), wherein, A target (11) is formed on the end side (10) of the anode head (6), and electrons collide with the target in the excited region (9) during operation. The anode head (6) provides a flow path (16) for cooling fluid, which extends from at least one inlet connection (14a) via a radially outer section (20), further via a cooling gap (21) and further via a radially inner section (22) to at least one outlet connection (15a). The excited region (9) of the target (11) is substantially annular, and in the region (26) of the anode head (6) opposite to the excited region (9) of the target (11), the local height (H1, H2) of the cooling gap (21) continuously increases from the radially outer to the radially inner.

2. The Röntgen ray tube (1) according to claim 1, characterized in that, The local cross-sectional area (F1, F2) of the cooling gap (21) continuously decreases from the radial outside to the radial inside in the region (26) of the anode head (6) opposite to the excited region (9) of the target (11), remaining the same or continuously increasing by a maximum of 15%.

3. The Röntgen ray tube (1) according to claim 1 or 2, characterized in that, The local cross-sectional area (F1, F2) of the cooling gap (21) continuously decreases from the radial outside to the radial inside in the region (26) of the anode head (6) opposite to the excited region (9) of the target (11), especially by a maximum continuous decrease of 20%.

4. The Röntgen ray tube (1) according to any one of the preceding claims, characterized in that, The flow path (16) is configured in the anode head (6) in a manner that is at least substantially rotationally symmetrical about the central axis (ZA).

5. The Röntgen ray tube (1) according to any one of the preceding claims, characterized in that, The radial outer segment (20) of the flow path (16) is formed at least substantially around the entire circumference of the anode head (6).

6. The Röntgen ray tube (1) according to any one of the preceding claims, characterized in that, A distribution structure (28) is formed in the radial outer section (20) of the flow path (16), which enables the cooling fluid flow from the at least one inlet connection (14a) to the cooling gap (21) to be distributed and homogenized on the circumference of the anode head (6).

7. The Röntgen ray tube (1) according to claim 6, characterized in that, The distribution structure (28) includes a set of (33; 33b) rectifier elements (34) for cooling fluid distributed around the anode head (6) in the sub-section (27b) near the target of the radial outer section (20). The rectifier elements extend between the annular gap (29b; 29d) on the inlet side and the annular gap (29c) or cooling gap (21) on the outlet side. The rectifier elements enable the establishment of at least substantially parallel sub-flows of cooling fluid and enable the separation of the sub-flows from each other.

8. The Röntgen ray tube (1) according to claim 6 or 7, characterized in that, The distribution structure (28) includes a set (33a) of rectifier elements (34) for cooling fluid distributed around the anode head (6) in the radially outer section (20) of the flow path (16) away from the target sub-section (27a; 27c). The rectifier elements extend between annular gaps (29a; 29b) on the inlet side and annular gaps (29b; 29d) on the outlet side. The rectifier elements enable the establishment of at least substantially parallel sub-flows of cooling fluid and enable the separation of the sub-flows from each other.

9. The Röntgen ray tube (1) according to claims 7 and 8, characterized in that, The annular gap (29b; 29d) on the outflow side of the rectifier element (34) of the subsection (27a; 27c) that is far from the target is also the annular gap (29b; 29d) on the inflow side of the rectifier element (34) of the subsection (27b) that is close to the target, and the group (33b) of the rectifier element (34) of the subsection (27b) that is close to the target is offset from the group (33a) of the rectifier element (34) of the subsection (33a) that is far from the target in the azimuth direction with respect to the central axis (ZA).

10. The Röntgen ray tube (1) according to any one of claims 7 to 9, characterized in that, The rectifier element (34) is oriented at least substantially in the axial direction, and correspondingly the sub-flow of the cooling fluid is oriented at least substantially in the axial direction.

11. The Röntgen ray tube (1) according to any one of claims 7 to 10, characterized in that, The rectifier element (34) is at least partially composed of the following: - Parallel blades (34a; 34b; 34e), especially straight parallel blades (34a), and / or - Trapezoidal (34c) or triangular blades (34e), and / or - Teardrop-shaped (34b) or rhomboid leaves, The blades (34a; 34b; 34c; 34e) are formed on the radially outward oriented wall side (38) and / or the radially inward oriented wall side (39) of the anode head (6), wherein the radially outward oriented wall side (38) and the radially inward oriented wall side (39) together define the radially outer segment (20) of the flow path (16).

12. The Röntgen ray tube (1) according to any one of claims 7 to 11, characterized in that, The rectifier element (34) is at least partially composed of a plurality of parallel hollow structures (34d) disposed in the radially outer segment (20) of the flow path (16), and in particular, the plurality of parallel hollow structures (34d) constitute a honeycomb structure.

13. The Röntgen ray tube (1) according to any one of claims 6 to 12, characterized in that, The distribution structure (28) includes one or more swirling elements (30; 36) in the radially outer section (20) of the flow path (16) in a sub-section (27a) away from the target. The swirling elements are disposed between the at least one inlet connection (14a) and the annular gap (29b) on the outflow side, and the swirling elements are used to introduce swirling flow about the central axis (ZA) into the cooling fluid flow.

14. The Röntgen ray tube (1) according to claim 13, characterized in that, The at least one swirling element (30) extends spirally around the central axis (ZA) of the anode head (6), thereby establishing at least one spiral channel (31) for the flow of cooling fluid.

15. The Röntgen ray tube (1) according to claim 13 or 14, characterized in that, Multiple swirling elements (30) extend spirally around the central axis (ZA) of the anode head (6), thereby establishing multiple spiral channels (31) that are azimuthally and / or axially staggered for the sub-flow of the cooling fluid.

16. The Röntgen ray tube (1) according to any one of claims 6 to 15, characterized in that, A homogenization region (32) for cooling fluid flow is established between the distribution structure (28) of the radial outer segment (20) away from the target sub-segment (27a; 27c) and the distribution structure (28) of the radial outer segment (20) near the target sub-segment (27b), and in particular, the homogenization region (32) is established as an annular gap (29b; 29d).

17. The Röntgen ray tube (1) according to any one of the preceding claims, characterized in that, The anode head (6) is configured to have a first flow element (18) and a second flow element (19), the first flow element and the second flow element being interlocked with each other and forming at least a portion therebetween the flow path (16).

18. The Röntgen ray tube (1) according to any one of the preceding claims, characterized in that, At least the radial inner section (22) of the flow path (16) and, if necessary, the cooling gap (21) are partially limited by a plunger portion (23) that extends into the interior of the anode head (6) from the end side (10) of the anode head (6).

19. A Röntgen ray tube arrangement structure (40), comprising a Röntgen ray tube (1) according to any one of the preceding claims and a means (17) for supplying cooling fluid, wherein, The supplying device (17) provides fresh cooling fluid to the delivery discharge section (14b) and the delivery discharge section (14b) is connected to the at least one inlet connection section (14a). In particular, the supplying device (17) also receives heated cooling fluid to the return inlet section (15b) and the discharge connection section (15a) is connected to the return inlet section (15b).

20. The application of the Röntgen ray tube (1) according to any one of claims 1 to 18 or the Röntgen ray tube arrangement structure (40) according to claim 19, wherein, During the operation of the Röntgen ray tube (1): - Electrons are struck by a source (4) used to release electrons onto a ring-shaped excited region (9) of the target (11), thereby generating X-rays, and - The cooling fluid flows from the radial outside to the radial inside in the cooling gap (21) opposite to the excited region (9).

21. The application according to claim 20, characterized in that, The average flow velocity of the cooling fluid in the cooling gap (21) placed in the excited region (9) remains the same or increases from the radial outside to the radial inside, especially increasing by a maximum of 25%.

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