X-ray source with electromagnetic pump

Abstract

An electromagnetic pump for pumping a conductive liquid is disclosed, the electromagnetic pump comprising a first conduit section and a second conduit section, a current generator arranged to provide a current through the liquid in the first conduit section and the liquid in the second conduit section such that the direction of the current intersects the flow of the liquid in the first conduit section and the second conduit section, and a magnetic field generator arranged to provide a magnetic field through the liquid in the first conduit section and the second conduit section such that the direction of the magnetic field intersects the direction of the liquid flow and the direction of the current.

Description

[Technical field]

[0001] The invention disclosed herein relates generally to electromagnetic pumps, and more particularly to an x-ray source including one or more electromagnetic pumps for pumping a conductive liquid used as a target in the x-ray source. [Background technology]

[0002] Traditionally, x-rays have been produced by bombarding a solid anode target with an electron beam, but thermal effects at the anode limit the performance of x-ray sources.

[0003] One way to mitigate the problems with overheating of solid anode targets has been to use a liquid metal jet as an electron target in generating X-rays. Thus, liquid metal jet X-ray sources are based on the generation of X-ray radiation by interaction between an electron beam and a liquid metal jet. Such a jet of liquid metal is able to withstand strong electron beam bombardment due to its regenerative properties. An example of such a system is disclosed in WO 2010 / 112048. In this system, the liquid metal jet is supplied in a closed loop manner by a pressurizing means, a jet nozzle and a reservoir for collecting the liquid metal at the end of the jet.

[0004] However, the use of liquid metal jets as electron targets has been found to entail potential weaknesses. For example, due to pressure fluctuations and inefficiencies resulting from the pumps used to pressurize the liquid metal, the uniformity of the jet may be less than optimal in terms of velocity, shape, and thickness (cross-sectional size). Furthermore, pumps typically require regular and time-consuming maintenance, which can result in increased operational costs and system downtime. Summary of the Invention

[0005] It is an object of the present invention to address at least some of the above mentioned drawbacks.A particular object is to provide an improved electromagnetic pump and an X-ray source comprising such a pump.

[0006] By way of preamble, a brief background and some challenges related to systems for delivering liquid jets will be presented.

[0007] An X-ray source of the above type may include an electron gun and a system for providing a stable jet of pressurized liquid metal in the vacuum chamber. The metal used is preferably one that has a relatively low melting temperature, for example indium, gallium, tin, lead, bismuth, or mixtures or alloys thereof. The electron gun may work by the principles of cold field emission, thermal field emission, thermionic emission, etc. The system for providing the electron bombardment target, i.e. the liquid jet, may include a heater and / or cooler, a pressurizing means, a jet nozzle, and a reservoir for collecting the liquid at the end of the jet. X-ray radiation is generated in the impact area as a result of the interaction between the electrons and the liquid target. A window with suitable transmission properties allows the generated X-ray radiation to be emitted from the vacuum chamber. To allow continuous operation of the X-ray source, it is generally desirable to collect the liquid in a closed-loop manner.

[0008] In the state of the art, supplying and pressurizing a liquid jet can be difficult, in particular the pumps used to pressurize and circulate the liquid can be less than satisfactory, for example due to pressure fluctuations caused by the movement of the pump pistons, or due to a lack of capacity to build up a sufficiently high pressure.

[0009] Leakage of the liquid, i.e. the target material, is another potential challenge. Leakage can result in metal being lost permanently outside the system. Other problems with leakage include the occurrence of situations where the metal freezes in parts of the system that are difficult or virtually impossible to access. Furthermore, seals, piping, and pumps can all cause liquid leakage and are therefore weak points in the liquid jet delivery system. From the user's perspective, leakage requires the refilling of expensive liquid, shortens maintenance intervals, and generally makes the operation and maintenance of the associated x-ray source more difficult and time-consuming. The present invention aims to address at least some of these challenges.

[0010] The present invention is based on the insight that at least some of the above-mentioned drawbacks of the prior art can be alleviated by using an electromagnetic pump for the target liquid.

[0011] Electromagnetic pumps for conducting liquids are known in the prior art, but have not been employed to generate liquid metal jets for use as targets in electron beam bombardment X-ray sources. One reason for this is that prior art electromagnetic pumps are unable to achieve sufficiently high pressures.

[0012] To generate a liquid metal jet for use as a target in an electron beam impact X-ray source, it is typically necessary to pressurize the liquid to more than 100 bar. One way to achieve such high pressures, at least in principle, is to connect multiple electromagnetic pumps in series. However, this increases the occurrence of seals and piping that constitute potential leak points, as discussed above, and also requires additional electrical connections. Thus, in an embodiment of the invention, an electromagnetic pump is provided with multiple sections in a single body to continuously increase the pressure along the pump to a sufficient level.

[0013] Thus, according to a first aspect of the inventive concept, an electromagnetic pump for pumping a conductive liquid is proposed herein, comprising: a first conduit section having an inlet and an outlet; and a second conduit section having an inlet and an outlet; wherein each of the conduit sections is arranged to provide a flow of liquid from its inlet to its outlet; The outlet of the first conduit section is fluidly connected to the inlet of the second conduit section.

[0014] The pump further comprises: a current generator arranged to provide a current through the liquid in the first conduit section and the liquid in the second conduit section such that the direction of the current intersects the flow of the liquid in the first conduit section and the second conduit section; and a magnetic field generating device arranged to provide a magnetic field through the liquid in the first conduit section and the second conduit section such that the direction of the magnetic field is transverse to the direction of the liquid flow and the electric current; Here, the first conduit section and the second conduit section are configured to provide a liquid flow direction in the first conduit section that is opposite to a liquid flow direction in the second conduit section.

[0015] Accordingly, some embodiments of the present invention may include an electromagnetic pump including at least a first and a second section. A first permanent magnet may be disposed in the first section and a second permanent magnet may be disposed in the second section, the first and second permanent magnets being disposed with opposite magnetic field orientations. To achieve a pumping force in the same direction along the liquid metal in both sections, the winding direction of the conduit in the first section may be opposite to the winding direction of the conduit in the second section. In this way, current may flow in the same direction through the entire device. It is understood that such a device may be extended to any number of sections, with the magnetic field orientation and winding direction of the conduit being switched between each section accordingly.

[0016] An increase in pressure in a conductive liquid may be achieved by a magnetic force resulting from the interaction between a magnetic field and an electric current flowing through the liquid. The direction of the magnetic force is approximately perpendicular to a plane that contains both the magnetic field and the direction of the electric current, and by orienting this plane to be substantially perpendicular to the length of the conduit, a flow of the liquid may be induced through the conduit. The magnetic force on a current carrying conductor may be written as:

number

[0017] It is further envisioned that the electromagnetic pump may be configured to pump the electrically conductive fluid. Such an arrangement may have any of the features and advantages disclosed in this disclosure.

[0018] The first conduit section may be configured to provide a liquid flow direction opposite to that provided by the second conduit section, and the current may maintain substantially the same main direction through both sections. As a result, magnetic forces generated by the interaction between the magnetic field and the current may point in opposite directions between the two sections. This may be compensated for by reversing the liquid flow direction in the second conduit section, such that the resulting flow may flow through both conduit sections.

[0019] The magnetic field generator may be arranged to provide a magnetic field in the first conduit section that is opposite in direction compared to the magnetic field in the second conduit section, and the current may maintain substantially the same main direction through both sections.

[0020] In order to fully understand the concepts of the present invention, some terms can first be further clarified.

[0021] The main pumping direction of an electromagnetic pump may be defined as the vector between the inlet of a first conduit section and the outlet of a second conduit section, and thus the "direction" of flow in a conduit section is understood as the direction of flow in the conduits of said conduit section, which is not necessarily the same as the main pumping direction.

[0022] Additionally, each conduit section may also have a section direction defined as the vector between the inlet of the conduit section and the outlet of the conduit section.

[0023] The liquid flow direction in a first conduit section being "opposite" to the liquid flow direction in a second conduit section may be defined, for example, as left-handed and right-handed flow orientations in the respective conduit sections, e.g., left-handed and right-handed spiral or helical flow, respectively, or as section directions in the respective conduit sections being substantially opposite each other.

[0024] Opposite directions of liquid flow in each conduit section may be achieved by having mirrored sections, i.e., a first conduit section having a first layout and a second conduit section having a second layout that is mirrored relative to the first layout. It is further envisioned that opposite directions of liquid flow in each conduit section may be achieved by reversing the flow direction of substantially identical conduit sections, i.e., a first conduit section having a first layout and a second conduit section having the first layout, where a first opening of the first conduit section serves as an inlet, a second opening of the first conduit section serves as an outlet, a first opening of the second conduit section corresponding to the first opening of the first conduit section serves as an outlet, and a second opening of the second conduit section corresponding to the second opening of the first conduit section serves as an inlet.

[0025] Throughout this disclosure, reference is made to "Type 1" and "Type 2" polarities of magnetic field generators, and examples of such types are the south and north poles, respectively, of a magnetic field generator, e.g., the north and south poles, respectively, of a permanent magnet.

[0026] Each of the conduit sections may include a conduit for holding the liquid. The conduit may include a duct, a tube, and / or a pipe. The tubes may be advantageous in that they may be arranged such that the cross section is square, rectangular, etc. Such a cross section may be beneficial to provide an interconnection arrangement that allows the current to travel through each of the conduit sections. In particular, a rectangular cross section may provide an interface between the conduits of the conduit section with a relatively large surface area compared to a circular cross section. On the other hand, a circular cross section pipe may provide higher mechanical strength for a given wall thickness since the hoop stress is the same throughout the cross section, whereas a rectangular cross section would exhibit stress concentrations at the corners. The conduit may be formed by assembling at least two machined parts. The conduit may be formed by 3D printing of a suitable conductive material. Preferably, the conduit should be made of a non-magnetic material to ensure that the magnetic field penetrates the liquid being pumped. In some embodiments, the conduit may be constructed of a stainless steel tube.

[0027] The conductive liquid may be or may include gallium, indium, tin, lead, bismuth, or alloys thereof.

[0028] A compact pump may be realized by the electromagnetic pump according to the concept of the present invention. In particular, the opposite orientation in each conduit section may provide a more compact arrangement of the magnetic field generating devices. In some embodiments, the conduit sections may be associated with respective magnetic field generators. Such magnetic field generators may have opposite polarities between the conduit sections, which may provide a compact arrangement of the magnetic field generators without requiring intermediate material between the magnetic field generators to close the magnetic circuit. The magnetic field generators may be embodied as permanent magnets, such as neodymium magnets.

[0029] Furthermore, electromagnetic pumps according to the concepts of the present invention may provide pumps with fewer (or no) moving parts compared to conventional pumps for conductive liquids, which may facilitate easier maintenance and reduce the risk of pressure fluctuations caused by moving parts.

[0030] Throughout this disclosure, several examples of conduit sections are disclosed, it being understood that further variations of the conduit sections are contemplated within the concepts of the present invention.

[0031] The first conduit section may include a coil having windings in a first direction and the second conduit section may include a coil having windings in a second direction, the first direction being opposite to the second direction.

[0032] The electromagnetic pump may further comprise a yoke surrounding the first conduit section and the second conduit section, the yoke comprising a ferromagnetic material such as iron, magnetic steel, etc. The yoke may be arranged to provide mechanical support. In particular, the yoke may be configured to withstand pressure generated via a force exerted by the electromagnetic pump on the conductive liquid. The yoke may also provide routing of the magnetic field, i.e., the yoke may provide for the containment of the magnetic flux generated by the magnetic field generating device.

[0033] The electromagnetic pump may further comprise a core of ferromagnetic material. The core may provide a closure of a magnetic circuit, i.e. the core may provide a path along which the magnetic flux generated by the magnetic field generating device is confined.

[0034] As will be described in more detail below, to confine the magnetic field, the outer yoke may have a thickness of at least 20% of the diameter of the core. Preferably, taking into account that there is typically a gap between the core and the yoke, the thickness of the yoke may be at least 20% of the diameter of the core plus 6% of the radial distance between the core and the yoke. Such a yoke thickness substantially confines the magnetic field within the electromagnetic pump, thereby virtually eliminating interference with the electron beam of the x-ray source.

[0035] The outlet of the first conduit section may be fluidly connected to the inlet of the second conduit section by an intermediate reservoir formed by an inner wall and an outer wall of the electromagnetic pump. The inner wall may be a core of the aforementioned electromagnetic pump. The outer wall may be a yoke of the aforementioned electromagnetic pump. It is also envisaged that the inner wall and / or the outer wall may be formed by a magnetic field generating device. It is further envisaged that the electromagnetic pump may comprise a separate element providing the inner wall and / or the outer wall forming the intermediate reservoir. The intermediate reservoir may further be formed by at least a portion of the first conduit section and at least a portion of the second conduit section. By providing an intermediate reservoir, a simple fluid connection between the first conduit section and the second conduit section may be achieved.

[0036] The outlet of the first conduit section and the inlet of the second conduit section may be part of one and the same structure, ie the first conduit section and the second conduit section may be a single part.

[0037] The outlet of the first conduit section may be fluidly connected to the inlet of the second conduit section by an intermediate conduit, whereby a simple fluid connection between the first and second conduit sections may be achieved.

[0038] The electromagnetic pump may be further configured to allow electrical current to flow from the first conduit section to the second conduit section. This may be accomplished, for example, at least in part, by the intermediate reservoir described above. A conductive liquid may fill the intermediate reservoir and conduct electrical current from the first conduit section to the second conduit section. It is also envisioned that the electromagnetic pump may include an intermediate conductive element, such as a conductive cuff as described below. The intermediate conductive element may be positioned to conduct electrical current from the first conduit section to the second conduit section.

[0039] Each of the conduit sections may include a liquid path and an interconnect arrangement configured to allow an electric current to travel within each of the conduit sections from an inlet to an outlet of each of the conduit sections a distance shorter than the liquid path. The liquid path may be defined by the geometry of the conduit, i.e., the path of travel along the conduit along which the liquid flows. In contrast, the electric current is not restricted to travel along the liquid path by the interconnect arrangement. The interconnect arrangement may include direct contact between different portions of the conduit of the conduit section and / or contact between different portions of the conduit of the conduit section achieved, for example, by soldering or brazing. It is further envisioned that the conduit may include an inner surface that has been treated with an etchant. The inner surface of the conduit is the surface intended to contact the liquid. Treating the inner surface with an etchant may improve the interface between the conduit and the liquid for conducting electric current. The interconnect arrangement may include or be a conductive material, such as a metal, such as copper. In a further embodiment, the interconnect arrangement may be provided to fill the space between the conduit section and the surrounding wall, thus providing both electrical contact and mechanical support.

[0040] The magnetic field generating device may include a permanent magnet. It is further envisaged that the magnetic field may be provided by, for example, an electromagnet. The inventive concept provides a technique that allows multiple magnetic field generators to be combined in a space-efficient manner. Furthermore, the magnetic field generating device may comprise a magnetic field generator associated with each conduit section, each magnetic field generator comprising multiple magnetic field generating elements. Such a magnetic field generating element may represent, for example, a sector, i.e., a portion of the circumference of the conduit section relative to the main axis.

[0041] The electromagnetic pump may further include a conductive cuff disposed between the first and second conduit sections to allow electrical current to travel from the first conduit section to the second conduit section. This may facilitate electrical routing of the electromagnetic pump as electrical current may pass between the conduit sections, eliminating the need for separate routing to each conduit section. The conductive cuff may include an open section that allows fluid connection from an outlet of the first conduit section to an inlet of the second conduit section.

[0042] The first conduit section and the second conduit section may be arranged consecutively along a main axis. The main axis may coincide with a main pump direction defined earlier in this disclosure. Furthermore, the main axis may be a longitudinal axis of the electromagnetic pump. The first conduit section and the second conduit section being arranged consecutively may be understood as the conduit sections being arranged in series along the main axis. Furthermore, the first conduit section and the second conduit section may be centered on the main axis.

[0043] The first conduit section may comprise a first coil wound in a first direction about the major axis, and the second conduit section may comprise a second coil wound in a second direction about the major axis, the second direction being opposite to the first direction. In other words, the first conduit section may include a first helix wound in a first direction about the major axis, i.e., one of a right-handed and left-handed helix, and the second conduit section may include a second helix wound in a second direction about the major axis, i.e., the other of the right-handed and left-handed helix.

[0044] Adjacent turns of the first coil and the second coil, respectively, may be in electrical contact with each other such that electrical current may travel through each conduit section.

[0045] The magnetic field generating device may comprise a first magnetic field generator arranged to at least partially surround the first conduit section and a second magnetic field generator arranged to at least partially surround the second conduit section, the first magnetic field generator arranged with type 1 magnetic poles facing radially towards the first conduit section and type 2 magnetic poles facing radially away from the first conduit section, the second magnetic field generator arranged with type 1 magnetic poles facing radially away from the second conduit section and type 2 magnetic poles facing radially towards the second conduit section, the type 1 magnetic poles and type 2 magnetic poles being of opposite polarity. These features are further described in relation to Figures 2 and 3.

[0046] The magnetic field generating device may include a first magnetic field generator arranged on an inlet side of the first conduit section, with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section, and a second magnetic field generator arranged on an outlet side of the first conduit section and on an inlet side of the second conduit section, with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially towards the second conduit section, wherein the type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

[0047] Adjacent turns of the first coil and the second coil, respectively, may be in electrical contact with each other such that electrical current may travel through each conduit section.

[0048] These features are further explained in relation to FIG.

[0049] The first conduit section may include a first spiral shape disposed substantially transversely to the major axis, and the second conduit section may include a second spiral shape disposed substantially transversely to the major axis, and the first and second spiral shapes may each be disposed in a single plane.

[0050] The magnetic field generating device comprises a first magnetic field generator arranged at the inlet side of the first conduit section, with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section, and a second magnetic field generator arranged at the outlet side of the first conduit section and at the inlet side of the second conduit section, with type 1 magnetic poles facing axially towards the second conduit section and type 2 magnetic poles facing axially towards the first conduit section, the type 1 magnetic poles and type 2 magnetic poles being of opposite polarity. These features are further described in relation to FIG. 6.

[0051] According to a second aspect, there is provided an electromagnetic pump for pumping a conductive liquid, which may be configured similarly to the electromagnetic pump disclosed above in relation to the first aspect and embodiment. It should be understood, however, that the pump according to this aspect differs in that it may comprise a single conduit section and therefore does not necessarily comprise more than one conduit section. As with the first aspect and embodiment, the electromagnetic pump may comprise a current generator arranged to provide a current through the liquid in the conduit section such that the direction of the current is intersecting with the flow of the liquid in the conduit section, and may further comprise a magnetic field generator arranged to provide a magnetic field through the liquid in the conduit section such that the direction of the magnetic field is intersecting with the flow of the liquid and the direction of the current.

[0052] In some embodiments, the electromagnetic pump according to the first or second aspect may be configured to allow fluid to be present between the conduit section(s) and the inner surface of the outer wall of the electromagnetic pump. Fluid may therefore be present outside the conduit to balance the pressure exerted by liquid inside the conduit on the conduit wall. Advantageously, balancing the pressure difference across the conduit wall in this way allows the pump to operate at liquid pressures that would otherwise risk damaging the conduit section. In other words, the wall thickness of the conduit section may be reduced, as the wall section is exposed to a lower pressure difference due to the liquid outside the conduit section.

[0053] The fluid may be formed, for example, from a conductive liquid pumped through an electromagnetic pump, and in one example may be provided by a fluid connection between the inside of the conduit and the space between the conduit and the surrounding outer wall. This fluid connection may be provided, for example, via an intermediate reservoir formed by the inner and outer walls of the electromagnetic pump, as described above. The fluid flowing outside the conduit may be considered as being in parallel flow to the liquid being pumped, provided that the space between the conduit and the surrounding wall forms an open connection from the inlet to the outlet of the conduit section. A pumping force is also exerted on this fluid when an electric current is passed through it.

[0054] It is also conceivable within the scope of the invention to provide different liquids on the outside of the conduit section. In such a case, means may be provided to prevent mixing of the two liquids. In a further embodiment, the space between the conduit section and the surrounding inner wall may be filled with an incompressible potting compound, for example an epoxy.

[0055] According to a third aspect of the inventive concept, there is provided an x-ray source comprising a liquid target generator configured to form a liquid target of a conductive liquid, an electron source configured to provide an electron beam that interacts with the liquid target to generate x-ray radiation, and an electromagnetic pump according to any of the preceding aspects of the inventive concept.

[0056] For practical reasons, e.g. to avoid losses and feed-through in radiation shields and vacuum enclosures, the pump is preferably located close to or even inside the vacuum chamber. Such an arrangement of the electromagnetic pump may result in interference with the electron beam. In an embodiment of the invention, interference with the electron beam from the electromagnetic pump is reduced or even eliminated by using an electromagnetic pump having a yoke for the magnetic circuit that is thick enough to prevent magnetic leakage. To this end, a liquid metal jet X-ray source may be provided in which the thickness of the outer yoke is at least 20% of the diameter of the core, preferably at least 20% of the core diameter plus 6% of the radial distance between the core and the yoke. Both the core and the yoke are preferably made of the same ferromagnetic material, such as iron, magnetic steel, etc. The X-ray source may include a closed loop circulation system, such as a recirculation path in which the electromagnetic pump is integrated. Furthermore, the X-ray source may comprise a collection reservoir for collecting liquid discharged from the liquid target generator.

[0057] Depending on the properties of the liquid metal used for the target material, the electromagnetic pump described above may need to operate at different temperatures. Two non-limiting examples may be gallium, with a melting point of 30°C, and indium, with a melting point of 157°C. To avoid losing performance at higher temperatures, any part of the magnetic circuit that does not contain magnetic material should be kept as small as possible. In other words, the gap between the poles should be narrowed. However, a conduit that transports the liquid metal typically exists in this gap, so that a reduction in the gap width reduces the pump capacity. To solve this, a liquid metal jet X-ray source may be provided with a suitably designed electromagnetic pump. The electromagnetic pump may comprise a hollow cylindrical radially magnetized permanent magnet having an outer first diameter and an inner second diameter, and a cylindrical core having a third diameter arranged concentrically with said permanent magnet, the distance between the inner diameter of the magnet and the diameter of the core being less than the product of the third diameter and the difference between the first and second diameters divided by the sum of the first and second diameters. The x-ray source may also incorporate a yoke for the magnetic circuit that is thick enough to prevent magnetic leakage. Additionally, the electromagnetic pump may include multiple sections to achieve the desired pump performance.

[0058] Several modifications and variations are possible within the scope of the third aspect. In particular, X-ray sources and systems with more than one liquid target or more than one electron beam are considered within the scope of the inventive concept. Furthermore, X-ray sources of the type described herein may be advantageously combined with X-ray optics and / or detectors tailored to specific applications, exemplified by but not limited to medical diagnostics, non-destructive testing, lithography, crystallography, microscopy, materials science, microscopy surface physics, protein structure determination by X-ray diffraction, X-ray photospectroscopy (XPS), critical dimension small angle X-ray scattering (CD-SAXS), and X-ray fluorescence (XRF).

[0059] Additionally, variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0060] A feature described in relation to one embodiment may be incorporated in other embodiments, and the advantages of that feature are applicable to all embodiments in which it is incorporated.

[0061] Other objects, features, and advantages of the inventive concepts will become apparent from the following detailed disclosure, from the appended claims, as well as from the drawings.

[0062] In general, all terms used in the claims should be interpreted according to their ordinary meaning in the art unless expressly defined otherwise herein. Moreover, the use of terms such as "first," "second," and "third" herein does not denote any order, quantity, or importance, but is used to distinguish one element from another. All references to "a / an / the [element, device, component, means, step, etc.]" should be openly interpreted as referring to at least one instance of said element, device, component, means, step, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the order disclosed, unless expressly stated.

[0063] The above as well as additional objects, features, and advantages of the inventive concept will be better understood through the following illustrative, non-limiting detailed description of different embodiments of the inventive concept, with reference to the accompanying drawings. [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 illustrates diagrammatically a first conduit section and a second conduit section. [Diagram 2] FIG. 2 illustrates diagrammatically in cross-section an electromagnetic pump. [Diagram 3] FIG. 3 illustrates a schematic cross-sectional view of an embodiment of a first conduit section and a second conduit section. [Figure 4] FIG. 4 illustrates a further embodiment of a first conduit section and a second conduit section diagrammatically in cross section. [Figure 5a] FIG. 5a illustrates diagrammatically in cross section a further embodiment of a first conduit section and a second conduit section. [Figure 5b] FIG. 5b illustrates a further embodiment of the first and second conduit sections in a cross-sectional view. [Figure 6] FIG. 6 illustrates a further embodiment of a first conduit section and a second conduit section diagrammatically in cross section. [Figure 7] FIG. 7 illustrates diagrammatically an X-ray source with an electromagnetic pump. [Figure 8] FIG. 8 illustrates a schematic of the core and yoke geometry of one embodiment. [Figure 9] FIG. 9 is a cross-sectional view illustrating the dimensions and size of one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] These figures are not necessarily to scale and generally show only those parts necessary to clarify the concept of the invention; other parts may be omitted or may merely be suggested.

[0066] 1, a first conduit section 102 and a second conduit section 104 are illustrated. The first conduit section 102, here comprising a tube or pipe, is arranged as a right-handed spiral, and the second conduit section 104, here comprising a tube or pipe, is arranged as a left-handed spiral. The first conduit section 102 may be fluidly connected to the second conduit section via an intermediate conduit 157. Illustrated are the direction B of a magnetic field generated by a magnetic field generating device (not shown), the direction I of current, and the direction P of flow within each conduit section. As shown, the direction B of the magnetic field, the direction I of current, and the direction P of flow are all perpendicular to each other.

[0067] 2 illustrates an electromagnetic pump 100 for pumping a conductive liquid in a cross-sectional view along a main axis A of the electromagnetic pump 100. The electromagnetic pump 100 here comprises four conduit sections 102, 104, 106, 108. However, it should be understood that the electromagnetic pump 100 may comprise at least a first conduit section 102 having an inlet 110 and an outlet 112, and a second conduit section 104 having an inlet 114 and an outlet 116, each of these conduit sections 102, 104 being arranged to provide a flow of liquid from its inlet to its outlet. The outlet 112 of the first conduit section 102 is further fluidly connected to the inlet 114 of the second conduit section 104. The further conduit sections 106, 108 illustrated in this embodiment may be considered as a repeat of the first conduit section 102 and the second conduit section 104, i.e., the first conduit section 102 and the second conduit section 104 are followed by yet another first conduit section 106 and second conduit section 108. In this regard, the terms "first conduit section" and "second conduit section" may be considered as a reference to a type of conduit section rather than a particular conduit section.

[0068] The electromagnetic pump 100 further comprises a current generator 120 arranged to provide a current through the liquid in the first conduit section 102 and the liquid in the second conduit section 104 such that the direction of the current is substantially perpendicular to the flow of liquid in the first conduit section 102 and the second conduit section 104. The direction of the current and the flow of liquid in the conduit sections are more clearly illustrated in Figure 3. It should be noted that the current generator 120 may be connected to points other than those illustrated in Figure 2.

[0069] The electromagnetic pump 100 further comprises a magnetic field generator 122 arranged to provide a magnetic field through the liquid in the first conduit section 102 and the second conduit section 104 such that the direction of the magnetic field is substantially perpendicular to the direction of liquid flow and current flow. As above, the direction of the magnetic field is more clearly illustrated in FIG.

[0070] The first conduit section 102 and the second conduit section 104 are configured to provide a liquid flow direction in the first conduit section 102 that is opposite to the liquid flow direction in the second conduit section 104 .

[0071] Furthermore, the electromagnetic pump 100 may comprise a main inlet 124 and a main outlet 126 for receiving and discharging the liquid, respectively. Furthermore, the electromagnetic pump 100 may comprise a yoke 128 surrounding the first conduit section 102 and the second conduit section 104. The yoke 128 comprises a ferromagnetic material. Furthermore, the yoke 128 comprises end pieces 130, 132 respectively arranged before the first conduit section of the electromagnetic pump 100, here the first conduit section 102, and after the last conduit section of the electromagnetic pump 100, here the second conduit section 108. In this regard, the terms "before" and "after" are made with respect to a main flow direction M defined by a flow vector between the main inlet 124 and the main outlet 126. In particular, the term "before" may be interchangeable with the term "upstream" and the term "after" may be interchangeable with the term "downstream". The yoke end pieces 130, 132 may provide routing for the magnetic field. A core 129 is also disposed in the electromagnetic pump 100. Thus, the magnetic field may emanate from the inner pole of the magnetic field generator 122, pass radially through the conduits of the first conduit section 102, through the core 129, the end pieces 130, and the yoke 128, and enter the outer pole of the magnetic field generator, thus completing a closed magnetic circuit.

[0072] The electromagnetic pump 100 may further include lids 136, 138 configured to be connected to the yoke 128. The lids 136, 138 may provide mechanical support and a feedthrough for the conductive liquids 124, 126 and the electrical current I. In particular, the lids 136, 138 may be configured to withstand pressure generated via forces exerted by the electromagnetic pump 100 on the conductive liquid.

[0073] 3, a first conduit section 102 and a second conduit section 104 are illustrated in cross-sectional view. The main flow direction is now indicated in the figure by direction M. A main axis A is also indicated. The first conduit section 102 and the second conduit section 104 are now arranged consecutively along the main axis A.

[0074] The first conduit section 102 comprises a first coil 140 wound in a first direction around the main axis A, and the second conduit section 104 comprises a second coil 142 wound in a second direction around the main axis, the second direction being opposite to the first direction. In other words, the first conduit section 102 comprises a first coil 140 that is one of a right-handed coil and a left-handed coil, and the second conduit section 104 comprises a second coil 142 wound in a second direction around the main axis, i.e. the other of a right-handed coil and a left-handed coil. From the illustrated cross-sections, it is not possible to infer the specific orientation of the conduit sections 102, 104, i.e. whether they are left-handed or right-handed coils. In contrast, what is important is that the first conduit section 102 and the second conduit section 104 have opposite orientations, respectively.

[0075] In the illustrated cross-section, the flow of liquid in the first conduit section 102 is indicated by flow directions 144 and 146, and the flow direction in the second conduit section 104 is indicated by flow directions 145 and 147, with the flow propagating out of the illustrated plane (indicated by dots) or into the illustrated plane (indicated by crosses).

[0076] The direction of current I through the liquid in the first conduit section 102 and the second conduit section 104 is shown, where the direction of current I is substantially perpendicular to the flow of liquid in the first conduit section 102 and the second conduit section 104.

[0077] The electromagnetic pump 100 further comprises a magnetic field generating device, here comprising a first magnetic field generator 148 arranged to at least partially surround the first conduit section 102 and a second magnetic field generator 150 arranged to at least partially surround the second conduit section 104, where the first magnetic field generator 148 has a type 1 magnetic pole 152 (in this example a south pole S) facing radially towards the first conduit section 102 and a type 2 magnetic pole 154 (in this example a south pole S) facing radially towards the first conduit section 102. The first magnetic field generator 148 and the second magnetic field generator 150 are arranged with type 1 magnetic poles 152 (in this example, south pole S) facing radially away from the first conduit section 102 and type 2 magnetic poles 154 (in this example, north pole N) facing radially towards the second conduit section 104, the type 1 magnetic poles 152 and type 2 magnetic poles 154 being of opposite magnetic poles. Due to the arrangement of the first magnetic field generator 148 and the second magnetic field generator 150, the magnetic fields generated by the respective magnetic field generators 148, 150 are mutually closed by each other.

[0078] The magnetic circuit provided by each magnetic field generator 148, 150 passes through the liquid in the first conduit section 102 and the second conduit section 104, respectively, such that the direction of the magnetic field is substantially perpendicular to the direction of the liquid flow and the current I.

[0079] A yoke 128 that surrounds the first and second conduit sections 102, 104, and a core 129 are also visible in the illustrated cross section.

[0080] The intermediate reservoir 156 is fluidly connected to the outlet 112 of the first conduit section and the inlet 114 of the second conduit section 104. The intermediate reservoir 156 is here formed by the core 129, the outer wall 158, and at least a portion of the first conduit section 102 and at least a portion of the second conduit section 104. Thus, a conductive liquid (not shown) may flow from the first conduit section 102 through the intermediate reservoir 156 into the second conduit section 104. The conductive liquid located in the intermediate reservoir 156 may also serve to pass the current I from the first conduit section 102 to the second conduit section 104. It is further envisioned that an intermediate conductive element, such as a conductive cuff (not shown), may be disposed between the first conduit section 102 and the second conduit section 104. The intermediate conductive element may extend about the major axis A, thus increasing the contact area between the intermediate conductive element and each of the first and second conduit sections 102, 104. One embodiment of such an intermediate conductive element may be represented by an open cuff, with an opening in the cuff forming a portion of the intermediate reservoir 156.

[0081] The outer wall 158 may be electrically insulating and / or may be made from an electrically insulating material.

[0082] Each conduit section 102, 104 may further comprise an interconnect arrangement. The interconnect arrangement may be configured to allow electrical current to travel within each of the conduit sections. In particular, the interconnect arrangement may be configured to allow electrical current to travel in a direction perpendicular to the flow direction within each conduit section. The interconnect arrangement may be configured to conduct electrical current.

[0083] Referring now to Figure 4, a similar arrangement is shown as described in relation to Figure 3. To avoid repeating features already described, similar elements between the embodiments described in relation to Figures 2, 3 and 4 will not be further described in the following sections. The main flow direction is indicated by direction M.

[0084] The magnetic field generating device here comprises a first magnetic field generator 148 arranged on the inlet side 111 of the first conduit section 102 with type 2 magnetic poles 154 facing axially towards the first conduit section 102 and type 1 magnetic poles 152 facing axially away from the first conduit section 102. A second magnetic field generator 150 is arranged on the outlet side 113 of the first conduit section 102 and on the inlet side 115 of the second conduit section 104 with type 2 magnetic poles 154 facing axially towards the first conduit section 102 and type 1 magnetic poles 152 facing axially towards the second conduit section 104, the type 1 magnetic poles 152 and type 2 magnetic poles 154 being of opposite polarity. The term "axial" here refers to the main axis A. Additionally, the first magnetic field generator 148 is now a cylinder having a first diameter 160 that is smaller than a first coil diameter 161 of the coil in the first conduit section 102. Similarly, the second magnetic field generator 150 is a cylinder having a second diameter 163 that is smaller than a second coil diameter 165 of the coil in the second conduit section 104.

[0085] The first magnetic field generator 148 is positioned to provide a magnetic field through the liquid in the first conduit section 102 such that the direction of the magnetic field is substantially perpendicular to the direction of the liquid flow and the current I. The second magnetic field generator 150 is positioned to provide a magnetic field through the liquid in the second conduit section 104 and the liquid in the first conduit section 102 such that the direction of the magnetic field is substantially perpendicular to the direction of the liquid flow and the current I.

[0086] In the illustrated cross-section, the flow of liquid in the first conduit section 102 is indicated by flow directions 144 and 146, and the flow direction in the second conduit section 104 is indicated by flow directions 145 and 147, with the flow propagating out of the illustrated plane (indicated by dots) or into the illustrated plane (indicated by crosses).

[0087] The magnetic field circuit lines are illustrated in FIG. 4, where the magnetic fields provided by the respective magnetic field generators 148, 150 pass through the liquid in the first conduit section 102 and the second conduit section 104, respectively, such that the direction of the magnetic field is substantially perpendicular to the direction of the liquid flow and the current I.

[0088] An intermediate conductive element 162, e.g., a conductive cuff, is disposed between the first conduit section 102 and the second conduit section 104. The intermediate conductive element 162 is now also disposed in front of the first conduit section 102. The intermediate conductive element 162 may extend about the main axis A, thus increasing the contact area between the intermediate conductive element 162 and the first conduit section 102 and the second conduit section 104, respectively.

[0089] The outlet 112 of the first conduit section 102 may be fluidly connected to the inlet 114 of the second conduit section 104 by an intermediate reservoir, as described in connection with Figure 3, and / or by an intermediate conduit (not shown). The intermediate conduit may extend substantially the same distance from the major axis A as the first and second conduit sections.

[0090] 5a and 5b, further embodiments of the first conduit section 102 and the second conduit section 104 are illustrated. For clarity, some parts of the electromagnetic pump are omitted here in the figures. It should be noted that the illustrated figures are merely schematic and are not necessarily to scale.

[0091] Referring initially to Figure 5a, a cross-sectional view illustrates several conduit sections 102, 104, 106, 108. An interconnect arrangement 158 ​​is arranged within each of the conduit sections 102, 104, 106, 108 to allow a current I to travel a distance from an inlet to an outlet of each of the conduit sections that is less than the liquid path. The liquid path of the first conduit section 102 is illustrated here as path P, and the distance traveled by the current from an inlet to an outlet of the first conduit section 102 is shown as distance D. Each conduit section in the illustrated embodiment may have a serpentine shape.

[0092] The flow of liquid in the first conduit section 102 is shown here with a flow direction 144. The positive direction is also shown with an arrow having a (+) sign for clarity. It can thus be seen that the flow of liquid in the first conduit section 102 follows a substantially positive direction. The flow of liquid in the second conduit section 104 is shown with a flow direction 145. The flow direction in the second conduit section 104 is opposite to the flow direction in the first conduit section 102, i.e. the flow direction 145 in the second conduit section 104 is substantially opposite to the indicated positive direction. This arrangement and the resulting flow are partly made possible by the arrangement of the magnetic field generating devices, which will be further described in relation to FIG. 5b.

[0093] 5b, there is illustrated a cross-sectional view of a further embodiment of the first conduit section 102 and the second conduit section 104. The cross-sectional view is perpendicular to the cross-sectional view illustrated in connection with FIG 5a.

[0094] Here, several conduit sections are illustrated. Each conduit section is associated with a respective magnetic field generator. For example, a first magnetic field generator 148 is arranged to at least partially surround the first conduit section 102. The first magnetic field generator 148 is arranged with a type 1 magnetic pole 152 and a type 2 magnetic pole 154 such that a magnetic field circuit passes through the conduit and the liquid in the conduit is substantially perpendicular to the direction of the current I. Furthermore, the arrangement of the magnetic field generators 148, 150 may serve to close the magnetic field circuit between the two magnetic field generators.

[0095] 6, a further embodiment of the first conduit section 102 and the second conduit section 104 is illustrated. For clarity, some parts of the electromagnetic pump are omitted from the illustration here. It should be noted that the illustrated view is merely schematic and is not necessarily to scale.

[0096] Each conduit section in the illustrated embodiment may be formed as a spiral shape in a single plane. For example, the first conduit section 102 may be formed as a spiral shape in a single plane S1, and the second conduit section 104 may be formed as a spiral shape in a single plane S2. The first conduit section 102 and the second conduit section 104 preferably have the same orientation, i.e., both are either clockwise or counterclockwise rotating spirals. However, the direction of liquid flow in the first conduit section 102 and the second conduit section 104, respectively, is opposite in that it flows radially from the outer portion of the first conduit section 102 to the inner portion of the first conduit section 102 and flows radially from the inner portion of the second conduit section 104 to the outer portion of the second conduit section 104.

[0097] Further, now there is provided an outer current conductor 164 and an inner current conductor 166. Current I is directed from the outer current conductor 164 to the inner current conductor 166 through the conduit sections and optionally an interconnect arrangement configured to allow the current to travel within each conduit section, thereby causing current to flow from one side of the conduit, through the conductive liquid to the opposite side of the conduit, and further, optionally through the interconnect arrangement, to a nearby portion of the conduit.

[0098] The magnetic field generating device comprises a first magnetic field generator 148 arranged on the inlet side 111 of the first conduit section 102, with type 2 magnetic poles 154 facing axially towards the first conduit section 102 and type 1 magnetic poles 152 facing axially away from the first conduit section 102, and a second magnetic field generator 150 arranged on the outlet side 113 of the first conduit section 102 and on the inlet side 115 of the second conduit section 104, with type 2 magnetic poles 154 facing axially towards the second conduit section 104 and type 1 magnetic poles 152 facing axially towards the first conduit section 102, the type 1 magnetic poles and type 2 magnetic poles being opposite magnetic poles.

[0099] The intermediate conduit 157 is here disposed between the first conduit section 102 and the second conduit section 104, the intermediate conduit 157 providing a fluid connection between the outlet 112 of the first conduit section 102 and the inlet 114 of the second conduit section 104.

[0100] 7, an X-ray source 170 is illustrated comprising a liquid target generator 172 with a nozzle configured to form a liquid target 174 of a conductive liquid, an electron source 176 configured to provide an electron beam that interacts with the liquid target 174 to generate X-ray radiation 177, and an electromagnetic pump 100 according to the inventive concept. The liquid target 174 may be a liquid jet. Thus, the electromagnetic pump 100 according to the inventive concept may be configured and / or suitable to provide a liquid jet. The X-ray source 170 may further comprise a low pressure chamber 178 or a vacuum chamber 178. A recirculation path 180 may also be arranged in liquid communication with a collection reservoir 182 for collecting liquid discharged from the liquid target generator 172 and in liquid communication with the liquid target generator 172. The generated X-ray radiation 177 may exit the X-ray source 170 by transmission through an X-ray transmissive window 184.

[0101] As illustrated in Fig. 7, the electromagnetic pump 100 may be located within a vacuum chamber 178 in relatively close proximity to an electron source 176. It may therefore be advantageous to take measures to ensure that the pump does not magnetically interfere with the electron beam. An embodiment taking this into account will be described with reference to Fig. 8.

[0102] A schematic cross-sectional view of two sections of an electromagnetic pump according to the present disclosure is shown in FIG. 8. FIG. 8 is similar to FIG. 3, and the same reference numbers are used in this description. However, some reference numbers have been omitted in FIG. 8 to avoid cluttering the figure. The liquid metal is transported in a tube, e.g., a thin-walled stainless steel tube, wound around a central core. The flow direction of the liquid metal in the tube is indicated by dots (flow out of the plane of the figure) and crosses (flow into the plane of the figure).

[0103] In some embodiments, liquid may also flow on the outside of the tube, thereby reducing the pressure difference between the two sides of the tube wall. More generally, the tube (i.e., the conduit for the liquid metal) may be immersed or buried in an incompressible medium. Such an incompressible medium may be a co-flow of the same liquid metal as inside the tube, or may be another liquid separated from the liquid metal inside the tube. It is also contemplated that the incompressible medium may be an incompressible potting compound, such as, for example, an epoxy. The incompressible medium may also provide an electrical connection between adjacent tube walls.

[0104] To maximize the magnetic field through the liquid metal and thereby maximize the pumping force, the inner core C and the outer yoke Y are preferably made from a ferromagnetic material. Thus, both the core and the outer yoke may comprise iron, magnetic steel, or the like. In the embodiment of FIG. 8, the magnetic field generator is a permanent magnet disposed between the core and the yoke. Permanent magnets may be advantageous because no electrical feedthroughs are required for the generation of the magnetic field, thereby allowing for a less complex design.

[0105] The length of one section is indicated by the arrow b in Figure 8. As shown in the figure, each section has a permanent magnet. The length b of one segment is limited by the saturation magnetization of the (iron) core. Assuming circular symmetry, which may be the typical case, this condition can be written as:

number

number

[0106] From the corresponding discussion of the outer yoke Y, we obtain the minimum thickness of the yoke to contain the magnetic field. Again, for a circular symmetry with the inner yoke diameter φ1 and the outer yoke diameter φ2, the following condition applies:

number

number

[0107] Inserting an upper limit for b that corresponds to utilizing as much flux as possible in the core, this equation transforms to:

number

number

number

[0108] It can be appreciated that the thickness of the yoke should be at least 20% of the core diameter. In many embodiments, the magnet has a non-negligible thickness and a gap is necessary between the core and the yoke to make room for the tube carrying the liquid metal. Denoting by t the radial distance from the outside of the core to the inside of the yoke, the following applies:

number

number

number

number

number

[0109] Thus, as explained above, embodiments in which the thickness of the outer yoke is at least 20% of the core diameter, or preferably at least 20% of the core diameter plus 6% of the radial distance between the core and the yoke, have the advantage that magnetic leakage is prevented or at least greatly reduced, thereby eliminating or at least greatly reducing interference with the electron beam. A thick outer yoke also has the added advantage that a higher pressure can be maintained in and around the tube carrying the liquid metal.

[0110] In some embodiments of the present invention, it may also be preferred to consider the size of the gap in the magnetic circuit. To avoid performance degradation at high temperatures, the gap in the magnetic circuit should be as small as possible. However, reducing the gap may reduce the pump capacity. A consideration of this point is given below.

[0111] When designing an electromagnetic pump based on permanent magnets, the properties of the magnet material must be taken into account. Rare-earth permanent magnets, especially those based on neodymium, exhibit a reversible linear behavior, at least over some parameter ranges. This makes them particularly suitable for this type of device. However, with increasing temperature, the linear relationship breaks down at high demagnetizing fields. This drawback can be avoided if the point of application corresponds to a sufficiently high induced magnetic field. For rare-earth magnets, such as neodymium magnets, the magnitude of the induced magnetic field is generally larger than the magnitude of the demagnetizing field, i.e. B m >-μ0H m It is.

[0112] Referring to FIG. 9, for the cylindrical case, and assuming that the field does not leak to the surroundings, the following equation can be set:

number

number

number

number

number

number

[0113] FIG. 9 illustrates the measures used in the above equations and also shows the helical conduit provided in the annular space between the magnet and the core. As will be appreciated, an actual embodiment would also include a yoke to complete the magnetic circuit, but such a yoke is not shown in FIG. 9 for clarity. An embodiment having multiple sections with alternating magnet polarity and conduit winding direction can be used to achieve the desired pump performance. In FIG. 9, the magnet is shown as a single radially magnetized hollow cylinder, but could alternatively be comprised of multiple arc-shaped magnets assembled to obtain a cylindrical shape.

[0114] The pressure drop across the conduit decreases rapidly (to the fourth power) as the diameter of the conduit increases. This encourages implementations that make the diameter of the conduit, and therefore the gap in the magnetic circuit, larger. However, as the gap increases, the effective magnetic field also decreases, reducing the efficiency of the pump. The reduction in the magnetic field is a relatively weak function of the gap size. A preferred embodiment has a gap size close to the limit value δ / 2 derived above.

[0115] The inventive concept has been described above primarily with reference to certain embodiments, however, as will be readily apparent to those skilled in the art, other embodiments besides those disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims.

[0116] [List of reference numbers] A spindle b Segment length C Core I current M Mainstream direction N magnetic north pole S magnetic south pole S1 Single Plane S2 Single Plane t Radial distance between the core and the yoke Y York φ c Core Diameter Inner diameter of φ1 yoke Outer diameter of φ2 yoke 100 Electromagnetic Pump 102 First Conduit Section 104 Second Conduit Section 106 Conduit Section 108 Conduit Section 110 Entrance 111 Entrance side 112 Exit 113 Exit side 114 Entrance 115 Entrance side 116 Exit 120 Current Generator 122 Magnetic Field Generator 124 Main Entrance 126 Main exit 128 York 129 cores 130 End Piece 132 End Piece 136 Lid 138 Lid 140 First coil 142 Second Coil 144 Flow Direction 145 Flow direction 146 Flow Direction 147 Flow Direction 148 First magnetic field generator 150 Second magnetic field generator 152 Type 1 magnetic pole 154 Type 2 magnetic pole 156 Intermediate Reservoir 158 Exterior Wall 160 First Diameter 161 First coil diameter 162 Intermediate Conductive Element 163 Second Diameter 164 Outer current conductor 165 Second coil diameter 166 Inner Current Conductor 170 X-ray source 172 Liquid Target Generator 174 Liquid Target 176 Electron source 177 X-ray radiation 178 Low Pressure Chamber / Vacuum Chamber 180 Recirculation Path 182 Collection Reservoir 184 X-ray transparent window The following is a summary of the claims as originally filed: [1] An electromagnetic pump for pumping a conductive liquid, comprising: a first conduit section having an inlet and an outlet; a second conduit section having an inlet and an outlet; and Equipped with each of the conduit sections is arranged to provide a flow of the liquid from its inlet to its outlet; the outlet of the first conduit section is fluidly connected to the inlet of the second conduit section; The electromagnetic pump is a current generator positioned to provide the current through the liquid in the first conduit section and the liquid in the second conduit section such that the direction of the current intersects the flow of the liquid in the first conduit section and the second conduit section; a magnetic field generating device arranged to provide a magnetic field through the liquid in the first conduit section and the second conduit section such that the direction of the magnetic field intersects the direction of the liquid flow and the direction of the electric current; Further comprising: the first conduit section and the second conduit section are configured to provide a flow direction of the liquid in the first conduit section that is opposite to a flow direction of the liquid in the second conduit section. [2] The electromagnetic pump described in [1], further comprising a yoke surrounding the first conduit section and the second conduit section, the yoke comprising a ferromagnetic material. [3] The electromagnetic pump described in [1] or [2], further comprising a core of a ferromagnetic material. [4] An electromagnetic pump described in any one of [1] to [3], wherein the outlet of the first conduit section is fluidly connected to the inlet of the second conduit section by an intermediate reservoir formed by an inner wall and an outer wall of the electromagnetic pump. [5] The electromagnetic pump described in any one of [1] to [4], wherein the outlet of the first conduit section is fluidly connected to the inlet of the second conduit section by an intermediate conduit. [6] An electromagnetic pump described in any one of [1] to [5], further configured to allow the current to flow from the first conduit section to the second conduit section. [7] The electromagnetic pump described in any one of [1] to [6], wherein the magnetic field generating device includes a permanent magnet or an electromagnet. [8] The electromagnetic pump described in any one of [1] to [7], further comprising a conductive cuff disposed between the first conduit section and the second conduit section to enable the current to be conducted from the first conduit section to the second conduit section. [9] The electromagnetic pump described in any one of [1] to [8], wherein the first conduit section and the second conduit section are arranged continuously along a main axis.

[10] The electromagnetic pump described in [9], wherein the first conduit section comprises a first coil wound in a first direction around the main shaft, and the second conduit section comprises a second coil wound in a second direction around the main shaft, the second direction being opposite to the first direction.

[11] The electromagnetic pump of

[10] , wherein each of the conduit sections includes an interconnection arrangement configured to allow the current to travel between adjacent windings of a respective coil.

[12] The magnetic field generating device comprises: a first magnetic field generator disposed to at least partially surround the first conduit section; a second magnetic field generator disposed to at least partially surround the second conduit section; Equipped with the first magnetic field generator is arranged with type 1 magnetic poles facing radially towards the first conduit section and type 2 magnetic poles facing radially away from the first conduit section; the second magnetic field generator is arranged with the type 1 magnetic poles facing radially away from the second conduit section and the type 2 magnetic poles facing radially towards the second conduit section; The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

[10] 。 The electromagnetic pump according to claim 1.

[13] The magnetic field generating device comprises: a first magnetic field generator disposed on the inlet side of the first conduit section, with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section; a second magnetic field generator disposed at the outlet side of the first conduit section and at the inlet side of the second conduit section, with the type 1 magnetic poles facing axially towards the first conduit section and the type 2 magnetic poles facing axially towards the second conduit section; Equipped with The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

[10] 。 The electromagnetic pump according to claim 1.

[14] The first conduit section includes a first spiral shape disposed substantially transversely to the major axis, and the second conduit section includes a second spiral shape disposed substantially transversely to the major axis; The magnetic field generating device is a first magnetic field generator disposed on the inlet side of the first conduit section, with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section; a second magnetic field generator disposed at the outlet side of the first conduit section and at the inlet side of the second conduit section, with the type 1 magnetic poles facing axially towards the second conduit section and the type 2 magnetic poles facing axially towards the first conduit section; Preparation, The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

[10] 。 The electromagnetic pump according to claim 1.

[15] A liquid target generator configured to form a liquid target of a conductive liquid; an electron source configured to provide an electron beam that interacts with the liquid target to generate x-ray radiation; [1] to

[14] , and An X-ray source comprising:

Claims

1. 1. An electromagnetic pump for pumping a conductive liquid, comprising: a first conduit section having an inlet and an outlet; a second conduit section having an inlet and an outlet; and Equipped with each of the conduit sections is arranged to provide a flow of the liquid from its inlet to its outlet; the outlet of the first conduit section is fluidly connected to the inlet of the second conduit section; The electromagnetic pump is a current generator positioned to provide the current through the liquid in the first conduit section and the liquid in the second conduit section such that the direction of the current intersects the flow of the liquid in the first conduit section and the second conduit section; a magnetic field generating device arranged to provide a magnetic field through the liquid in the first conduit section and the second conduit section such that the direction of the magnetic field intersects the direction of the liquid flow and the direction of the electric current; Further comprising: the first conduit section and the second conduit section are arranged successively along a major axis and configured to provide a direction of flow of the liquid in the first conduit section opposite a direction of flow of the liquid in the second conduit section; the first conduit section comprises a first coil wound in a first direction about the main axis, and the second conduit section comprises a second coil wound in a second direction about the main axis, the second direction being opposite to the first direction; the outlet of the first conduit section is fluidly connected to the inlet of the second conduit section by an intermediate conduit; The first conduit section, the second conduit section, and the intermediate conduit comprise pipes of circular cross section.

2. 2. The electromagnetic pump of claim 1, further comprising a yoke surrounding the first conduit section and the second conduit section, the yoke comprising a ferromagnetic material.

3. 3. The electromagnetic pump of claim 1 or 2, further comprising a core of ferromagnetic material.

4. An electromagnetic pump according to any preceding claim, further configured to allow the current to flow from the first conduit section to the second conduit section.

5. The electromagnetic pump according to any one of claims 1 to 4, wherein the magnetic field generating device includes a permanent magnet or an electromagnet.

6. 6. The electromagnetic pump of claim 1, further comprising a conductive cuff disposed between the first conduit section and the second conduit section to enable the current to pass from the first conduit section to the second conduit section.

7. 2. The electromagnetic pump of claim 1, wherein each of the conduit sections comprises an interconnection arrangement configured to allow the current to travel between adjacent turns of a respective coil.

8. The magnetic field generating device is a first magnetic field generator disposed to at least partially surround the first conduit section; a second magnetic field generator disposed to at least partially surround the second conduit section; and Equipped with the first magnetic field generator is arranged with type 1 magnetic poles facing radially towards the first conduit section and type 2 magnetic poles facing radially away from the first conduit section; the second magnetic field generator is arranged with the type 1 magnetic poles facing radially away from the second conduit section and the type 2 magnetic poles facing radially towards the second conduit section; The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

2. The electromagnetic pump according to claim 1.

9. The magnetic field generating device is a first magnetic field generator disposed on an inlet side of the first conduit section, the first magnetic field generator being disposed with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section; a second magnetic field generator disposed at the outlet side of the first conduit section and at the inlet side of the second conduit section, with the type 1 magnetic poles facing axially towards the first conduit section and the type 2 magnetic poles facing axially towards the second conduit section; Equipped with The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

2. The electromagnetic pump according to claim 1.

10. the first conduit section includes a first spiral shape disposed substantially transversely to the major axis, and the second conduit section includes a second spiral shape disposed substantially transversely to the major axis; The magnetic field generating device is a first magnetic field generator disposed on an inlet side of the first conduit section, the first magnetic field generator being disposed with type 1 magnetic poles facing axially towards the first conduit section and type 2 magnetic poles facing axially away from the first conduit section; a second magnetic field generator disposed at the outlet side of the first conduit section and at the inlet side of the second conduit section, the second magnetic field generator being disposed with the type 1 magnetic poles facing axially towards the second conduit section and the type 2 magnetic poles facing axially towards the first conduit section; Preparation, The type 1 magnetic poles and the type 2 magnetic poles are opposite magnetic poles.

2. The electromagnetic pump according to claim 1.

11. a liquid target generator configured to form a liquid target of a conductive liquid; an electron source configured to provide an electron beam that interacts with the liquid target to generate x-ray radiation; The electromagnetic pump according to any one of claims 1 to 10. An X-ray source comprising:

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