Production method and target for laser-induced nuclear fusion

Abstract

The invention relates to a method for producing a target (200) of laser-induced nuclear fusion using a channel system (100). The channel system (100) comprises a first channel (110) for a first liquid (10), a second channel (120) for a second liquid (20), a third channel (130) for a third liquid (30), and a fourth channel (140) for a fourth liquid (40). The second channel (120), the third channel (130), and the fourth channel (140) open into the first channel (110) at different positions one after the other. The method comprises: introducing (S110) the first liquid (10) into the first channel (110); introducing (S120) the second liquid (20) into the second channel (120) such that a drop (210) of the first liquid (10) is formed within the second liquid (20) in the first channel; introducing (S130) the third liquid (30) into the third channel (130) such that a first surface layer (220) made of the second liquid (20) is formed on the drop (210); and forming (S140) a precursor of the target (200) by introducing the fourth liquid (40) into the fourth channel (140), such that a second surface layer (230) made of the third liquid (30) is formed on the first surface layer (220). The first liquid (10) is not miscible with the second liquid (20), the third liquid (30) is not miscible with the second liquid (20), and the fourth liquid (40) is not miscible with the third liquid (30).

Description

[0001] 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0002] Manufacturing process and target for

[0003] a laser-induced nuclear fusion

[0004] The present invention relates to a method for producing a target for laser-induced nuclear fusion, to a target of laser-induced nuclear fusion and in particular to microfluidically produced three-phase droplets for the direct production of foam-in-dish targets in a one-step process.

[0005] background

[0006] Shell targets for laser-induced nuclear fusion (nuclear fusion targets) serve on the one hand as containers for the fuel of nuclear fusion (e.g. a deuterium-tritium mixture) and on the other hand for the conversion of the energy of the incident laser beams into heat (ablation), whereby the impact layer is vaporized and energy is directed radially inwards to trigger nuclear fusion there.

[0007] The production of nuclear fusion targets currently involves several separate processes. First, foams and shells are produced. Then, the foam is placed in a shell, ensuring an even distribution within the shell. This procedure is complex, time-consuming, and prone to errors.

[0008] In addition to the aforementioned method, there is another method, such as that described in EP 3 166 112 Bi. Here, a spherical target consisting of several onion-shaped shells made of different polymers is produced, with the concentrically arranged polymer shells serving as containers for deuterium and tritium as fuel for nuclear fusion. This approach is also complex, as it utilizes a sophisticated array of nozzles that first form droplets which are then polymerized.

[0009] Therefore, especially for the highly repetitive fabrication of fusion targets, there is a need for further manufacturing processes for laser fusion targets or their precursors that overcome the aforementioned disadvantages.

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[0011] Brief description of the invention

[0012] At least some of the aforementioned problems are solved by a method for producing a target for laser-induced nuclear fusion according to claim 1 and a target according to claim 10. The dependent claims relate to advantageous embodiments of the subject matter of the independent claims.

[0013] The present invention relates to a method for producing a target for laser-induced nuclear fusion using a channel system. The channel system comprises a first channel for a first liquid, a second channel for a second liquid, a third channel for a third liquid, and a fourth channel for a fourth liquid. The method includes:

[0014] - Introducing the first liquid into the first channel;

[0015] - Introducing the second liquid into the second channel to form a drop of the first liquid inside the second liquid in the first channel;

[0016] - Introducing the third liquid into the third channel to form a first surface layer of the second liquid on the drop; and - forming the target by introducing the fourth liquid into the fourth channel to form a second surface layer of the third liquid on the first surface layer.

[0017] The first liquid is immiscible with the second, the third liquid is immiscible with the second, and the fourth liquid is immiscible with the third. The formation of droplets and / or surface layers can be achieved by controlling the volumetric flow rate or pressure of the liquid additions. Furthermore, the liquids can wet each other, allowing multiple liquid phases to be layered on top of or within each other.

[0018] Optionally, the process further includes: curing the third liquid into an ablation layer for laser-induced nuclear fusion, and / or curing the second liquid into a foam layer. The ablation layer is a layer that corresponds to page 2 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0019] The conversion of laser beams into kinetic energy serves to compress (and thereby heat) the fusion fuel. Advantageously, the ablation layer absorbs the laser radiation very well. At the same time, this layer acts as an outer seal to securely enclose the fusion material (deuterium and / or tritium) and thus seal the target.

[0020] Optionally, the curing steps include at least one of the following:

[0021] - a polymerization,

[0022] - a sol-gel process,

[0023] - a solvent exchange,

[0024] - a drying,

[0025] - drying at the critical point,

[0026] - irradiation (e.g., photocuring).

[0027] The sol-gel process is advantageously used to generate the foam or foam layer from the second liquid. During drying at the critical point, no phase boundary (liquid-gas) advantageously forms, thus avoiding artifacts and resulting in a very high-quality foam layer.

[0028] Optionally, the process further includes the removal of the initial liquid within the foam layer. According to exemplary embodiments, the removal of the initial liquid can be carried out simultaneously during the drying step of the foam layer. Both steps can therefore be performed together (in one process step). However, they can also be independent process steps that are carried out sequentially.

[0029] Optionally, the process further includes the following: opening the ablation layer and / or opening the foam layer (e.g., partially) and / or introducing a fuel for nuclear fusion into the foam layer. The opened layers can then be closed again.

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[0031] The fuel for nuclear fusion can, for example, contain at least one of the following substances: hydrogen, deuterium, tritium, deuterium-tritium mixture, boron: B11, helium: He3, lithium: Li6, Li7.

[0032] The channel system may further include or be coupled to a control device. The control device may be configured to adjust the flow rates of the first liquid and / or the second liquid and / or the third liquid and / or the fourth liquid. Optionally, the method then includes:

[0033] - Forming the first surface layer with a layer thickness of 50 to 300 pm by adjusting a relative volume flow rate between the first liquid and the second liquid; and / or

[0034] - Forming the second surface layer with a layer thickness of 5 to 100 pm by adjusting a relative volume flow rate between the second liquid and the third liquid.

[0035] The first surface layer can be approximately 100 pm thick. The second surface layer can be approximately 50 pm thick, or in a range of approximately...

[0036] The target can be 10 pm to 100 pm thick. The finished target can have a diameter of approximately 1–5 mm. However, these are only examples; the values ​​are almost infinitely adjustable (e.g., through volume controls or the diameter / dimensions of the channels).

[0037] Optionally, the formation of the first and / or second surface layer occurs concentrically through the generation of a dielectrophoretic force to compensate for gravity. Here, a tailored alternating electromagnetic field can be applied parallel or antiparallel to the direction of gravity, so that the electromagnetic force (e.g., of the dipoles) leads to a uniform alignment of the shells, i.e., gravitational deformations are compensated.

[0038] Optionally, the introduction of the third fluid (into the first channel) includes a

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[0040] Simultaneous introduction of the third fluid into the first channel from different sides. The different sides can be, for example, opposite each other.

[0041] Optionally, the introduction of the fourth fluid (into the first channel) includes the simultaneous introduction of the fourth fluid into the first channel from different sides. These different sides can, for example, be opposite each other.

[0042] Optionally, the second channel and the third channel (and optionally also the fourth channel) can flow into the first channel one after the other at different (axial) positions along a flow direction of the first fluid.

[0043] According to further embodiments, the first channel optionally comprises a first tubular section. The second channel optionally comprises a second tubular section. The third channel optionally comprises a third tubular section. Optionally, the third tubular section extends coaxially around the second tubular section. Likewise, the third tubular section can extend coaxially around the second tubular section. The first tubular section and / or the second tubular section and / or the third tubular section can project into the fourth channel together or sequentially. End sections of the first tubular section and / or the second tubular section and / or the third tubular section can be nozzle-shaped or cylindrical.The end sections can all terminate at the same axial position (along the direction of liquid flow). However, the second end section can also extend beyond the first, and similarly, the third end section can extend beyond the second. The extent of the extension can be less than the diameter of one of the droplets. In this embodiment of the channel system, at least the end sections can be arranged rotationally symmetrically about a common central axis of the coaxial configuration.

[0044] The term "tubular" should be understood to mean that the diameter does not have to be constant, but can be variable. The shape or form of the [page 5 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025]

[0045] The cross-section can be arbitrary. On the other hand, a cylindrical shape should have a constant cross-sectional area and a circular or oval cross-section.

[0046] Optionally, the channel wall(s) of the first channel and / or the fourth channel exhibit the following wettability:

[0047] - initial wettability with respect to the first liquid,

[0048] - a second wettability with respect to the second liquid,

[0049] - a third wettability with respect to the third liquid,

[0050] - a fourth wettability with respect to the fourth liquid.

[0051] The following optionally applies to these wetting applications:

[0052] - the first wettability is lower than the second wettability,

[0053] - the second wettability is lower than the third wettability,

[0054] - the third wettability is lower than the fourth wettability.

[0055] This ensures that the fourth liquid preferentially wets the channel wall. This prevents disturbances or fluctuations in the liquids, or the arrangement or sequence of the individual liquids or layers, from being compromised. The liquids or the surface material for the channels should be selected to meet the above conditions.

[0056] For example, one or more of the following materials can be used as surface material for the canal wall: a metal, a glass, a ceramic material.

[0057] The wettability of the capillaries can be adapted to the required conditions, for example, by means of coatings (plasma-enhanced chemical vapor deposition (PE-CVD), chemical vapor deposition (CVD), silanization (also from the liquid phase), etc.). In particular, the correct arrangement of the fluids in the channel / capillary can be taken into account. For the fluid system chosen here, the use of glass capillaries is a suitable option.

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[0059] which were coated with trichloro(iH,iH,2H,2H-perfluorooctyl)silane using CVD.

[0060] The diameters of the capillaries can be adjusted to suit the specific requirements. For example, the diameters of the (inner) capillaries could be 0.5 mm, the second (middle) capillary 1.2 mm, and the third (outer) capillary 2.6 mm. However, these will be adjusted to the specific experiment.

[0061] Optionally, the liquids in the process include the following materials:

[0062] The first liquid consists of water,

[0063] The second liquid comprises poly-4-methyl-i-pentene, PMP; the third liquid comprises trimethylpropane triacrylate, TMPTA; the fourth liquid comprises mineral oil or silicone oil.

[0064] It is understood here and in the following that the order in which process steps are listed does not necessarily correspond to the order in which the process steps are executed. The steps can be carried out in the order listed, but they can also be carried out in a different order (insofar as technically possible). Likewise, only some of the process steps need to be carried out.

[0065] Exemplary embodiments also relate to a target for laser-induced nuclear fusion. The target comprises: a spherical cavity which, when filled, contains a low-density gas; a foam layer for holding a fusion fuel, e.g., a mixture of deuterium and tritium; and an ablation layer for the thermal conversion of incident laser radiation. The foam layer surrounds the spherical cavity, and the ablation layer surrounds the foam layer.

[0066] Optionally, the foam layer can have a thickness ranging from 50 pm to 300 pm. The ablation layer can have a thickness ranging from 5 pm to 100 pm. The target can have a diameter ranging from 400 pm to 5 mm.

[0067] Page 7 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0068] Optionally, the foam layer contains a fuel for nuclear fusion. The fuel can be chosen almost freely.

[0069] Exemplary embodiments overcome the problems of conventional nuclear fusion target fabrication by forming a shell-shaped foam material to hold the fusion fuel (deuterium, tritium, or a mixture thereof). The fuel is therefore not contained in a (central) cavity within a shell-shaped container, but rather absorbed by the foam material, which then serves as the carrier matrix for the fuel. Even if the outer shell were not airtight, the fuel would remain within the foam material due to capillary action. The nuclear fusion target according to these exemplary embodiments is thus a foam-in-shell target suitable for proton fast ignition or, more generally, as a direct-drive target.

[0070] A key advantage of these embodiments lies in the simplified and automated mass production of the nuclear fusion targets or their precursors (e.g., without the fusion material). This can be achieved via a chip-based process that continuously supplies targets / precursors. The precursors are triple emulsion droplets (TEDs) produced microfluidically (chip-based or capillary-based). Compared to filling by differential pressure or using syringe pumps, microfluidics allows for increased dosing accuracy of foam materials within the tray. This, in turn, reduces the required amount of chemicals, as all liquids reach their destination without leaving any chemical residue. This simultaneously leads to a reduction in both the investment costs of the process and the ongoing operating costs.the consumables (chemicals) and ultimately a reduction in the overall costs for the production of the targets.

[0071] BRIEF DESCRIPTION OF THE FIGURES

[0072] The embodiments of the present invention are better understood by

[0073] Page 8 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0074] the following detailed description and the accompanying drawings, which, however, should not be understood as limiting the disclosure to the specific embodiments, but merely serve for explanation and understanding.

[0075] Fig. 1 shows a schematic flowchart for a process for manufacturing a laser fusion target.

[0076] Figs. 2A and 2B illustrate details of the production of the targets with a channel system as used according to the exemplary embodiments.

[0077] Fig. 3 shows a laser fusion target according to exemplary embodiments.

[0078] DETAILED DESCRIPTION

[0079] Fig. 1 shows a schematic flowchart for a process for producing a precursor or target for laser-induced nuclear fusion. The process utilizes a channel system comprising: a first channel for a first liquid, a second channel for a second liquid, a third channel for a third liquid, and a fourth channel for a fourth liquid. The process includes the following steps:

[0080] - Introducing S110 of the first liquid into the first channel;

[0081] - Introducing S120 of the second liquid into the second channel to form a drop of the first liquid inside the second liquid in the first channel;

[0082] - Introducing S130 of the third liquid into the third channel to form a first surface layer of the second liquid on the droplet; and

[0083] - Form S140 of the precursor / target by introducing the fourth liquid into the fourth channel to form a second surface layer from the third liquid on the first surface layer.

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[0085] The first liquid is immiscible with the second. The third liquid is immiscible with the second. The fourth liquid is immiscible with the third. In this way, the liquid phases remain separate. Therefore, the aforementioned droplets or surface layers form automatically upon introduction of the liquids. The surface tensions of the immiscible liquids cause the introduced liquids to assume a minimal surface area, resulting in the droplets or coatings. However, it is also important to ensure that at least the wettability of the outermost liquid on the channel wall is the best of all the liquids. Otherwise, a disturbance in the system could cause another liquid to wet the channel wall in order to minimize the energy of the overall system.According to exemplary embodiments, the liquids are therefore selected such that the liquid at the channel wall has a higher wettability than the other liquids of the droplet.

[0086] In the following, the liquids or the surface layers formed therefrom are also referred to as phases. In a subsequent post-treatment, the phases can be completely or partially cured (e.g., polymerized) so that the phases are no longer liquid. Both terms are used synonymously in this disclosure. For the sake of clarity, the same reference numerals are used.

[0087] Fig. 2A illustrates further details of the manufacturing process, as it can be carried out according to exemplary embodiments using a channel system 100. The channel system 100 shown comprises a first channel 110 for a first liquid 10 (first phase), a second channel 120 for a second liquid 20 (second phase), a third channel 130 for a third liquid 30 (third phase), and a fourth channel 140 for a fourth liquid 40 (fourth phase). The first liquid 10 is introduced into the first channel 110 under volume or pressure control and flows towards the other channels (second channel 120 to fourth channel 140). Downstream, the second channel 120, containing the second liquid 20, opens into the first channel 110. The second liquid 20, like the first liquid 10, can also be introduced into the first channel 110.

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[0089] The third liquid 30 is introduced into the first channel 110 via a volume- or pressure-controlled flow. Further downstream, the third channel 130, carrying the third liquid 30, enters the first channel 110. The third liquid 30 can also be introduced into the first channel 110 via a volume- or pressure-controlled flow. Finally, the fourth channel 140, carrying the fourth liquid 40, enters the first channel 110. The fourth liquid 40 can also be introduced into the first channel 110 via a volume- or pressure-controlled flow.

[0090] As a result of the volume control, the volume of liquid supplied per unit of time is regulated. The respective volume control can be set via the pressure value of one of the liquids 10, 20, 30, 40 relative to the pressure values ​​of the other liquids. According to exemplary embodiments, the liquids 10, 20, 30, 40 are immiscible—at least those adjacent to each other. Since the first liquid 10 is thus forced into the second liquid 20 (by the volume control), and due to the surface tension of the first liquid 10, a multitude of droplets 210 form successively within the second liquid 20. The droplet density or droplet size can be adjusted, for example, by the following parameters: channel diameter, surface tensions, and volumetric flow rates.

[0091] At the inlet of the third liquid 30 into the first channel 110, the inflowing third liquid 30 causes the second liquid 20 to be displaced from the channel wall (due, among other reasons, to its lower wettability) and to form a surface layer on the droplets. Since the second liquid 20 is also chosen to wet the first liquid 10, it cannot be completely wiped off by the third liquid 30. Thus, a first surface layer 220 forms on the droplets 210 from the first liquid 10 in the core. The droplets 210 coated in this way are then moved further within the third liquid 30. Advantageously, the third liquid 30 is not only introduced into the first channel 110 from one side, but from two or more sides (e.g., opposite sides). This ensures a homogeneous coating of the droplets 210 by the second liquid 20.

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[0093] This process is repeated when the fourth liquid 40 (through the fourth channel 140) enters the first channel 110. Since the third liquid 30 in turn wets the second liquid 20, the third liquid 30 is not completely wiped off by the fourth liquid 40, but forms a second surface layer 230. The doubly coated droplets 210 are then transported within the fourth liquid as a transport fluid. The doubly coated droplets 210 within the fourth liquid 40 are again controlled by volumetric flow rates. At the inlet of the fourth channel 140, the flow of the third liquid 30 is displaced from the channel wall (due to the better wettability of the channel wall by the fourth liquid), and – as a result of the surface wetting – the second surface layer 230 forms from within the third liquid 30.Advantageously, the fourth liquid 40 is introduced into the first channel 110 from two or more sides. This, in turn, provides the effect of achieving a homogeneous coating, i.e., the second surface layer 230 from the third liquid 30 is formed uniformly everywhere on the first surface layer 220.

[0094] Fig. 2B shows another embodiment of the channel system 100. In the channel system 100 shown, the first channel 110 comprises a first tubular section 117, the second channel 120 comprises a second tubular section 127, and the third channel comprises a third tubular section 137. The fourth channel 140 may also comprise a fourth tubular section 147. Optionally, the third tubular section 137 extends coaxially around the second tubular section 127. Likewise, the third tubular section 137 may extend coaxially around the second tubular section 127. The first tubular section 117 and / or the second tubular section 127 and / or the third tubular section 137 may project into the fourth channel 140 or the fourth tubular section 147 together or sequentially.The first tubular section 117 and / or the second tubular section 127 and / or the third tubular section 137 each comprise an end section from which the respective liquid exits. Some or all of the end sections may be nozzle-shaped or cylindrical. Fig. 2B.

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[0096] The cylindrical design is shown. The end sections can all terminate at the same axial position (along the direction of liquid flow). However, the end section of the second channel 120 can also project beyond the end section of the first channel 110. Similarly, the end section of the third channel 130 can project beyond the end section of the second channel 120. The amount of the projection can be less than the diameter of one of the droplets (TED 200). In this embodiment of the channel system 100, at least the end sections can be arranged rotationally symmetrically about a common central axis of the coaxial design. The central axis can run centrally from the first tubular section 117 and centrally from the fourth tubular section 147.

[0097] The channel system 100 according to the illustrated embodiment is also modular in design, with each module having a connection for one of the liquids 10, 20, 30, or 40. Thus, the channel system 100 comprises a first module 115, a second module 125, a third module 135, and a fourth module 145. The first module 115 includes a first connection 113 for the first channel 110 or the first liquid 10. The second module 125 includes a second connection 123 for the second channel 120 or the second liquid 20. The third module 135 includes a third connection 133 for the third channel 130 or the third liquid 30. The fourth module 145 includes a fourth connection 143 for the fourth channel 140 or the fourth liquid 40.

[0098] The module configuration shown can be expanded as desired, or some modules can be omitted. For example, the fourth module 145 is optional. The liquid droplets 200 can be pressed directly into a container with the fourth liquid 40 and collected.

[0099] The modules are connected to each other in a liquid-tight manner. For this purpose, suitable sealing elements 105 (e.g., O-rings) can be arranged between modules 115, 125, 135, and 145. Likewise, the connections 113, 123, 133, and 143 can be connected to the respective individual modules 115, 125, 135, and 145 in a liquid-tight manner via suitable sealing elements 105.

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[0101] In this embodiment as well, it is advantageous if the fourth liquid 40 has the highest wettability with respect to the fourth tubular section 147. In this way, the doubly coated droplets will not adhere to the channel wall of the fourth tubular section 147, but will be kept away from the channel wall; that is, a film of the fourth liquid 40 will always form between the channel wall and the doubly coated droplets.

[0102] The doubly coated liquid-core droplets 210 are so-called triple-emulsion droplets 200 (TEDs), which, according to exemplary embodiments, are a precursor for nuclear fusion targets 200. As shown in Figures 2A and 2B, the TEDs 200 can be continuously produced in the channel system 100 shown using chip- or capillary-based droplet microfluidics. The TEDs 200 are a special type of emulsion that—as explained above—consists of four immiscible fluids (the first liquid 10, the second liquid 20, the third liquid 30, and the fourth liquid 40), wherein the first liquid 10 is surrounded by the second liquid 20, which in turn is enclosed by an outer, third liquid 30. Thus, a fluid sphere is located inside two concentrically arranged hollow liquid spheres, similar to the structure of an onion. Due to the spatial constraints within the microchannels (e.g.,(The first channel 110, the second channel 120, the third channel 130, the fourth channel 140) the liquids are generally not yet arranged spherically within each other.

[0103] These double-coated droplets 200 are then transported along the first channel 110 within the transport liquid (fourth liquid / fourth phase 40) for further processing.

[0104] The finished nuclear fusion targets 200 are intended to form a foam within a shell, with the foam serving to hold the nuclear fusion material and the shell forming an ablation layer. For this purpose, the liquids in the TEDs 200 are cured and / or dried. Downstream of the channel system 100 shown, windows or transparent channel sections can be formed, for example, to trigger a curing process for the second and third liquids 20, 30 by means of irradiation or heating, and optionally a page 14 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0105] Drying should be carried out. This is described in more detail below.

[0106] According to exemplary embodiments, the third phase (third liquid 30) or the second surface layer 230 comprises a monomer that polymerizes to form the ablation layer 230 upon curing. The inner shell or first surface layer 220 comprises a material that is polymerized to foam, for example, in a subsequent sol-gel process. The foam then serves as a carrier material for a deuterium-tritium mixture. The inner or first phase (first liquid 10 of the droplet 210) is removed after the polymerization of the second phase 20 or the third phase 30. According to exemplary embodiments, it is also possible for the polymerization of the second phase (second liquid 20) and the third phase 30 to occur simultaneously. This can be achieved, for example, thermally or by means of light of a specific wavelength via a photoinitiator.The polymerization of the second phase 20 and the third phase 30 can also be carried out independently of each other, for example by choosing different photoinitiators. Thus, the outer, second surface layer 230 can first cure (to form the ablation layer). Subsequently, the foam layer 220 can be formed from the first surface layer 220 by a sol-gel process.

[0107] For subsequent nuclear fusion, it is advantageous if the layers (foam layer 220 and ablation layer 230) are formed as concentrically as possible with a constant thickness (as spherical spheres). Before curing, this concentricity of the individual layers 220 and 230 can be ensured, for example, by means of dielectrophoretic forces. Here, an alternating electromagnetic field is applied to both sides of a channel (e.g., channel 110) using the TEDs 200, with the alternating electromagnetic field acting parallel or antiparallel to gravity. This compensates for gravitational deformations of the layer thicknesses and thus ensures a concentric alignment of the layers 220 and 230. Curing / drying can then take place in this concentric arrangement, i.e., the transformation of the first surface layer 220 into the foam layer and the second surface layer 230 into the ablation layer.

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[0109] Fig. 3 shows an embodiment of a Target 200 or a precursor (TED) for such a Target 200. This Target 200 can be produced by the process described with Fig. 2. The Target comprises the three phases (the immiscible liquids / fluids 10, 20, 30):

[0110] - A first phase 210 or core phase: This can, for example, contain water. Before being used as a nuclear fusion target, this first phase 10 can be removed later (e.g., by diffusing out of the solidified second phase 20 / third phase 30). This creates a cavity 211 in the center of the target 200.

[0111] - a foam phase 220 (second phase 20): Forms from the second liquid 20 as a precursor material, which is polymerized to a sol-gel material and subsequently becomes the foam phase 220 by drying.

[0112] - A shell phase 230 (from the third phase 30): after polymerization, it serves as an ablation sphere shell or ablation layer, i.e., for coupling the laser beams to trigger nuclear fusion after filling.

[0113] The foam phase 220 serves to receive and fix the liquid fuel for nuclear fusion (e.g., deuterium, tritium, hydrogen, or a mixture thereof). Since the second phase 20 was arranged concentrically before hardening, the exemplary deuterium-tritium mixture in the foam phase 220 is also arranged concentrically. This offers an advantage for the nuclear fusion, which is triggered by coupling the laser beams into the ablation layer 230: The exemplary deuterium-tritium mixture is forced radially inward into the cavity 211 under high temperature and high pressure, in order to initiate nuclear fusion there when the ignition conditions are reached. Another advantage of the foam phase 220 lies in its capillary forces, which can be used to carry out the filling with nuclear fuel quickly and easily and to store it safely.

[0114] According to the exemplary embodiments, the curing (polymerization) of the ablation layer 230 can first take place. Subsequently, the polymerization of the foam-

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[0116] Layer 220 is formed, which can then be dried via diffusion through the cured ablation layer 230. Partial or final drying can also be carried out via the opened target 200 before filling with the deuterium-tritium mixture.

[0117] In the polymerization of the second phase 20 to form the foam layer 220, the sol-gel process described below is used, according to the exemplary embodiments. In this process, the second phase 20 is first converted into a gel by polycondensation of monomers, and the foam layer 220 is formed by subsequent drying. The gel results from the aggregation of monomers to oligomers that were previously dissolved in a solvent (sol). After polymerization, the solvent is located in the pores of the network structure that forms during polymerization. For example, liquid CO2 can be used to replace the solvent. The CO2 can also diffuse from the outside through the ablation layer 230 and replace the solvent there. Optionally, an "intermediate solvent" such as acetone can be used to first replace the solvent from the sol-gel process with acetone and then with liquid CO2.Drying can then be carried out by supercritical drying (e.g., drying at the critical point of the phase diagram). In this type of drying, no phase transition occurs, or the phase changes continuously. Consequently, significantly fewer drying artifacts are formed, and the quality of the foam is considerably improved. The resulting solid foam comprises aerogels. The described sol-gel process occurs either via photoinitiators or spontaneously after two precursor solutions are combined.

[0118] According to further embodiments, a photocurable material can also be used for the second phase 20 or foam layer 220, which cures via irradiation (e.g. using IR, UV etc.).

[0119] According to further embodiments, the layers of the targets 200 are not manufactured in parallel, but serially (see Fig. 2A), i.e., a large number of droplets 210 are first formed, which can stabilize on their way to the second channel 130 and form a shape that is as uniform as possible before the next page 17 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0120] Layer 220 is formed. After the third channel 130, the droplets have time to stabilize again before immersing themselves in the fourth liquid 140. It has been shown that this results in very homogeneous layer formation (with a predetermined, constant layer thickness). This procedure is also possible in the embodiment shown in Fig. 2B. For this purpose, the ends of the channels 127, 137 can be extended downwards accordingly, so that a plurality of spheres 210 also form there initially, before they are coated one after the other, with a relaxation phase provided between each coating according to exemplary embodiments (for homogenization).

[0121] According to further embodiments, the foam layer 220 in the shell 230 (ablation layer) is designed such that the nuclear propellant is drawn into the foam layer 220 via capillary forces. After filling, this creates a cavity in the center of the target 200 in which little or no nuclear propellant is present (for example, less than 10% or less than 30%). This has proven advantageous for nuclear fusion. To achieve this, the material of the foam layer 220 (e.g., PMP) and / or the pore size of the foam material 220 can be selected accordingly via the process parameters during manufacturing (e.g., via the sol-gel process).

[0122] According to further embodiments, the ablation layer 230 seals the foam layer 220 tightly and firmly, preventing introduced nuclear fuel from escaping through the ablation layer 230. Furthermore, this allows for a targeted increase in radial pressure during nuclear fusion, as nuclear fuel cannot escape through the (dense) ablation layer 230. This feature can also be achieved by using a suitable material for the ablation layer 230 (e.g., TMPTA) and / or by adjusting the manufacturing process parameters.

[0123] Advantages of exemplary embodiments lie particularly in the simpler process control and the reduction of process steps. For example, the following steps must be performed in the conventional manufacturing process for nuclear fusion targets mentioned at the beginning:

[0124] Page 18 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0125] (1) Production of so-called double emulsion droplets (DED, drop-in-droplet in a carrier medium) via a microfluidic process;

[0126] (2) Centering of the inner and outer droplet, whereby the outer droplet is embedded in the still liquid shell material (e.g., made of monomers), for which, for example, an adjustment of the densities or viscous forces are used; (3) Polymerization of the outer droplet to form a solid shell;

[0127] (4) Removal of the internal fluid, for example by drying;

[0128] (5) Forming a small opening for filling the dish (e.g., laser drilling); (6) Filling with a precursor still present as a monomer solution, for example, by filling using a needle or by a pressure difference;

[0129] (7) Rotate the dish filled with the polymer solution to distribute it evenly on the inside of the dish;

[0130] (8) Simultaneous polymerization of the monomer solution to form a sol-gel product; (9) Drying at a critical point of the sol-gel within the shell to form an aerogel.

[0131] Exemplary embodiments require significantly fewer manufacturing steps and therefore enable more efficient production of targets 200. The described "foam-in-shell" process for manufacturing TEDs 200 automatically forms the foam material 220 directly onto an inner surface of the shell material 230. Thus, there is no need to drill a hole in a hard shell (as in step 5 above) to introduce liquid foam material into the shell and then laboriously distribute it evenly onto an inner surface of the shell (as in step 7 above). According to exemplary embodiments, it is also possible to remove the first phase 10 along with the drying of the second phase 20. Both phases can diffuse out through the finished ablation layer 230 during drying. This could eliminate up to five process steps compared to a conventional manufacturing method for the targets.Thus, the (conventional) step (6) can be integrated into step (1), step (7) into step (2), step (4) into step (9), and step (5) is no longer required. The polymerization.

[0132] Page 19 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0133] With a suitable material combination (see below), the process can also be carried out in a single step according to the exemplary embodiments. Thus, the integration of steps (3) and (8) according to the exemplary embodiments is possible. In this way, the time required to manufacture the Fusiontargets 200 is significantly reduced, and the process's susceptibility to errors is further reduced.

[0134] Consequently, the production of the Nuclear Fusion Targets 200 is faster, more precise, and more cost-effective than with conventional methods. Furthermore, the application of chip-based or capillary-based microfluidic techniques allows for compliance with the required dosing accuracy. This also leads to a reduction in the reject rate. In these embodiments, the process is continuous until drying, eliminating the need for batch processing.

[0135] According to the exemplary embodiments, the following materials can be used: the first phase 10: water; the second phase 20: PMP (poly-4-methyl-i-pentene) dissolved in cyclohexane, precipitation in 1-hexanol or butanol; the third phase 30: TMPTA (trimethylpropane triacrylate); the fourth phase 40: mineral oil or silicone oil. The TED production process would take place at an elevated temperature (approx. 90 °C). Subsequently, the third phase 30 could be polymerized via a photoinitiator, and the second phase 20 could be foamed upon cooling.

[0136] According to further embodiments, other materials can also be used. For example, the following materials can also be used for the second phase 20:

[0137] Material chemical formula density pore size

[0138] RF C7H8O3 50 mg / cm3 <100 nm

[0139] PF C7H6O5 / CH2O 145 mg / cm3 <100 nm

[0140] PS C8H8 40 mg / cm3 4 m

[0141] PS-based NA 200 mg / cm3 NA

[0142] TMPTMA C15H2OO6 130 mg / cm3 NA

[0143] Page 20 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0144] TMPT C18H26O6 52 mg / cm3 ~pm

[0145] EGDM C10H20N204 59 mg / cm3 ~pm

[0146] DVB C10H10 20 mg / cm3 1-4 pm

[0147] PMP C6H12 2 mg / cm3 2-10 pm

[0148] DCPD-NB C10H12 / C7H10 25 mg / cm3 NA

[0149] The following materials can also be used for the third phase:

[0150] TMPTA (trimethylolpropane triacrylate)

[0151] Poly-alpha-methylstyrene

[0152] Poly(divinylbenzene)

[0153] where RF: resorcinol formaldehyde, PF: phenol formaldehyde, DCPD-NB: dicyclopentadi ene-norbornene, PS: polystyrene, EGDM: ethylene glycol dimethacrylate, DVB: divinylbenzene, DCPD: dicyclopentadiene.

[0154] The polymerization of the second liquid 20 and the third liquid 30 can be initiated, for example, by a photoinitiator or thermally, while concentricity can be ensured by applying electromagnetic or dielectrophoretic forces. The corresponding parameters must be set depending on the material used.

[0155] In summary, according to exemplary embodiments, targets or their precursors 200 comprise three concentrically arranged, immiscible liquids 10, 20, 30, which extend in an onion-like pattern from the inside out. A spherical core phase 210 is formed from the first liquid 10 and can later be removed. Above this, a monomer material (second liquid 20) acts as a precursor, which reacts to form a sol-gel in the subsequent process and can be dried using a suitable drying process, such as critical-point drying (CPD). An outer shell material 230 (made from the third liquid 30) envelops the monomer material 20 and is subsequently cured. Centering of the core 210 or the foam phase 220, as well as centering of the foam phase 220 in the shell phase 230, can be seen, for example, on page 21 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0156] This can be carried out using DEP (dielectric electrophoresis). This makes it possible to produce ablation sphere layers 230 already filled with foam or a corresponding monomer solution. In particular, this enables the production of foam-in-shell targets 200 in a single-step process (production of the liquid shell filled with a liquid that polymerizes into a foam material).

[0157] The features of the invention disclosed in the description, claims and figures may be essential for the realization of the invention, either individually or in any combination.

[0158] Page 22 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025

[0159] REFERENCE MARK LIST

[0160] 10 first liquid (first phase)

[0161] 20 second liquid (second phase)

[0162] 30 third fluid (third phase)

[0163] 40 fourth fluid (fourth phase)

[0164] 100-channel system

[0165] 105 Sealing elements (seals, O-rings, seals) 110 First channel

[0166] 113 first connection

[0167] 115 first module

[0168] 117 first tubular section

[0169] 120 second channel

[0170] 123 second connection

[0171] 125 second module

[0172] 127 second tubular section

[0173] 130 third channel

[0174] 133 third connection

[0175] 135 third module

[0176] 137 third tubular section

[0177] 140 fourth channel

[0178] 143 fourth connection

[0179] 145 fourth module

[0180] 147 fourth tubular section

[0181] 200 target(s) for laser-induced nuclear fusion

[0182] 210 drops (from first liquid, core phase)

[0183] 211 (central) cavity

[0184] 220 First surface layer (e.g., foam layer; foam phase) 230 Second surface layer (e.g., ablation layer; shell phase)

[0185] Page 23 of 29

Claims

207-0005DE - Triple Emulsion Droplet 07.11.2025 REQUIREMENTS 1. A method for producing a target (200) for laser-induced nuclear fusion using a channel system (100), wherein the channel system (100) has a first channel (110) for a first liquid (10), a second channel (120) for a second liquid (20), a third channel (130) for a third liquid (30) and a fourth channel (140) for a fourth liquid (40), the method comprising: Introducing (S110) the first liquid (10) into the first channel (110); Introducing (S120) the second liquid (20) into the second channel (120) so that a drop (210) of the first liquid (10) is formed within the second liquid (20) in the first channel; Introducing (S130) the third liquid (30) into the third channel (130) so that a first surface layer (220) of the second liquid (20) is formed on the drop (210); and Formation (S140) of the target (200) by introducing the fourth liquid (40) into the fourth channel (140), so that a second surface layer (230) is formed from the third liquid (30) on the first surface layer (220), where the first liquid (10) is immiscible with the second liquid (20), the third liquid (30) is immiscible with the second liquid (20), and the fourth liquid (40) is immiscible with the third liquid (30).

2. The method of claim 1, which further comprises the following: The second liquid (20) hardens to form a foam layer (220); Page 24 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025 Curing of the third liquid (30) to form an ablation layer (230) for laser-induced nuclear fusion.

3. The method of claim 2, wherein the curing steps comprise at least one of the following: - a polymerization, - a sol-gel process, - a drying, - drying at the critical point, - radiation therapy.

4. Method according to claim 2 or claim 3, which further comprises removing the first liquid (10) within the foam layer (220).

5. A method according to any one of claims 2 to 4, further comprising: Opening of the ablation layer (230) and / or the foam layer (220); Introducing a fuel for nuclear fusion into the foam layer (220).

6. The method of claim 5, wherein the fuel for nuclear fusion comprises one of the following substances: hydrogen, deuterium, tritium, boron: Bll, helium: He3, lithium: Li6, Li7.

7. A method according to any one of claims 1 to 6, wherein the channel system (100) further comprises a control device configured to adjust volume flows of at least one of the first liquid, the second liquid, the third liquid and the fourth liquid, and the method further comprises: Forming the first surface layer (220) with a layer thickness of 50 to Page 25 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025 200 pm by adjusting a relative volume flow rate between the first liquid (10) and the second liquid (20); and / or Forming the second surface layer (230) with a layer thickness of 5 to 50 pm by adjusting a relative volume flow between the second liquid (20) and the third liquid (30).

8. Method according to one of the preceding claims, wherein the formation of the first surface layer (220) and / or the second surface layer (230) is carried out concentrically by forming a dielectrophoretic force for gravitational compensation.

9. Method according to any one of the preceding claims, wherein the introduction of the third liquid (30) comprises the simultaneous introduction of the third liquid (30) from different sides into the first channel (110), and / or wherein the introduction of the fourth liquid (40) comprises the simultaneous introduction of the fourth liquid (40) into the first channel (110) from different sides.

10. Method according to one of the preceding claims, wherein the second channel (120) and the third channel (130) successively open into the first channel (110) at different positions along a flow direction of the first liquid (10).

11. Method according to any one of claims 1 to 9, wherein the first channel (110) has a first tubular section (117), the second channel (120) has a second tubular section (127), the third channel (130) has a third tubular section (137), Page 26 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025 and the third tubular section (137) extends coaxially around the second tubular section (117) and the third tubular section (137) extends coaxially around the second tubular section (127) and projects into the fourth channel (140), and wherein end sections of the first tubular section (117) and of the second tubular section (127) and of the third tubular section (137) are formed as nozzle-shaped or tubular.

12. Method according to any one of claims 1 to 11, wherein a channel wall of the first channel (110) and / or the fourth channel (140) has the following wettabilities: a first wettability with respect to the first liquid (10), a second wettability with respect to the second liquid (20), a third wettability with respect to the third liquid (30), a fourth wettability with respect to the fourth liquid (40), and where the following applies: The first wettability is lower than the second wettability. The second wettability is lower than the third wettability. The third wettability is lower than the fourth wettability.

13. Method according to any one of the preceding claims, wherein the first liquid includes water, the second liquid (20) comprises poly-4-methyl-i-pentene, PMP, the third liquid (30) comprises trimethylpropane triacrylate, TMPTA, the fourth liquid (40) comprises mineral oil or silicone oil.

14. One target (200) for laser-induced nuclear fusion comprising: Page 27 of 29 207-0005DE - Triple Emulsion Droplet 07.11.2025 a cavity (211); a foam layer (220) for receiving a fuel for nuclear fusion; and an ablation layer (230) for the thermal conversion of incident laser radiation, wherein the foam layer (220) surrounds the cavity (211) and the ablation layer (230) surrounds the foam layer (220).

15. The target (200) according to claim 14, wherein the foam layer (220) has a layer thickness in the range of 50 pm to 300 pm, and / or wherein the ablation layer has a thickness in the range of 5 pm to 100 pm, and / or the target has a diameter in the range of 400 pm to 5 mm.

16. The target (200) according to claim 14 or claim 15, wherein the foam layer (220) comprises a mixture of deuterium and tritium as fuel for nuclear fusion. Page 28 of 29

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