Arrangement for initiating an explosive, method for manufacturing an arrangement for initiating an explosive, and method for initiating an explosive

Abstract

Arrangement (1; 61) for initiating an explosive (3), comprising the explosive (3), wherein the explosive (3) is a secondary explosive; a first layer (6) arranged on the explosive (3), wherein the first layer (6) is applied directly to a surface of the explosive (3), wherein the first layer (6) is designed as a metal foil or metal plate glued onto the explosive (3), wherein the metal foil or metal plate is made of steel; a second layer (10) arranged on the first layer (6), wherein the second layer (10) is formed as an insulating layer with a material that is at least largely laser-permeable and covers at least parts of the first layer (6), wherein the second layer (10) is formed with a film made of a plastic material; and a laser beam delivery device (15; 55) configured to provide a laser beam (28, 29), in particular a laser pulse, in such a way that the laser beam (29) can penetrate the second layer (10) and act upon the first layer (6), wherein the laser beam delivery device (15; 55) comprises at least one laser diode (17); wherein the second layer (10) is designed such that the laser beam (29) can penetrate the second layer (10) essentially without damaging the second layer (10) or being affected by it in the form of absorption and reflection; wherein the second layer (10) is designed to amplify directional shock waves, which are generated by the action of the laser beam (29) on the first layer (6) during at least partial heating and vaporization, in the direction of the explosive (3) and to prevent the propagation of the shock waves in the opposite direction, away from the explosive (3), and a resulting reduction in the shock wave amplitude; and wherein the bonding of the metal foil or metal plate to the explosive (3) is carried out in such a way that an area in which the action of the laser beam (29) on the first layer (6) is provided is kept free of an adhesive layer.

Description

FIELD OF THE INVENTION

[0001] The invention relates to an arrangement for initiating an explosive. Furthermore, the invention relates to a method for producing an arrangement for initiating an explosive and a method for initiating explosives. TECHNICAL BACKGROUND

[0002] The invention and the problem underlying it will be explained below using the example of the initiation of a secondary explosive of a detonator, without, however, limiting the invention in this respect.

[0003] So-called secondary explosives are relatively insensitive to external influences compared to so-called primary explosives. From a safety perspective, a secondary explosive may therefore be well-suited for use in a detonator intended to detonate a larger main charge upon activation. However, it is comparatively more difficult to cause such a secondary explosive to react and thus convert, or initiating, it is also more difficult. In particular, the initiation of such secondary explosives requires very high pressure peaks in the explosive material.

[0004] Foil detonators, commonly known as "Exploding Foil Initiators" (EFIs), already exist for initiating secondary explosives. The desired pressure peaks for initiating the secondary explosive are achieved by an impact pulse on a Kapton® foil, which experiences extremely high acceleration due to the abrupt vaporization of a metal foil and the resulting plasma.

[0005] However, the design of such a detonator (EFI) is complex and laborious, and its function is influenced by a large number of parameters. The design, particularly the definition of the geometry and dimensions of the bridge shape and the layer structure, of such a detonator is based on experimental, empirical research, especially since a hermeneutic, computational design is difficult due to the complex processes in this system.

[0006] Changes to such a detonator therefore require a great deal of effort to determine the effects of such changes experimentally using hardware.

[0007] Furthermore, such foil detonators require electronics for their triggering that are designed for short-term high currents and voltages. This contributes to an increase in component volume and increased component costs.

[0008] In addition, the production of the layer structure of such foil detonators is complex and demanding.

[0009] In existing detonator concepts, it is often necessary to position the ignition electronics as close as possible to the explosive in order to optimize the inductance and resistance with regard to the ignition current.

[0010] It has already been proposed to initiate a secondary explosive using laser radiation generated by laser diodes. A concrete attempt to initiate a secondary explosive using laser diodes is described, for example, in the publication by Xiao FANG and Sheikh R. AHMAD, "Laser Ignition of an Optically Sensitised Secondary Explosive by a Diode Laser," Central European Journal of Energetic Materials, 2016, 13(1), 103-115. However, in this case, the explosive was mixed with an optical sensitizer, which absorbs the laser energy and is thus heated abruptly.

[0011] However, the effects of such an addition of a sensitizing additive to the actual secondary explosive on its properties are not fully known.

[0012] In the field of processing materials and their surfaces, there are also general processes for laser drilling and so-called “laser peening”.

[0013] The determination of drilling progress using piezo pressure sensors, with the aid of detection and evaluation of shock waves during laser drilling, is described, for example, in the publication “Real-time determination and control of the laser-drilled holes depth” by M. Stafe, C. Negutu, IM Popescu, Department of Physics, University “Polytechnica” of Bucharest, Spl. Independentei, nr. 313, Bucharest, 060042, Romania.

[0014] It would be desirable to be able to avoid the addition of a sensitizer to the actual secondary explosive in order to prevent any undesirable effects of such additional substances on the explosive, such as a deterioration of its storage life or service life or other properties. Modifying the secondary explosive by adding an additive may also require additional effort, such as documentation, testing, qualification, and the like, which would be desirable to avoid.

[0015] DE 38 38 896 A1 describes a laser-initiated ignition / ignition element provided with a storage layer. The ignition / ignition element is described with a housing whose opening is closed by a window made of BK7 glass. A light-absorbing layer is applied to a roughened inner surface of the window, which layer is in direct thermal contact with a pressed-on explosive. DE 38 38 896 A1 describes the production of the light-absorbing layer using thin-film technologies such as sputtering and vapor deposition. Among other things, the use of metals and metal compounds to form the light-absorbing layer is described. In DE 38 38 896 A1, the layer upstream of the explosive is intended to act as an intermediate thermal storage device.

[0016] A system for laser detonation of an explosive is described in US 4 917 014 A, whereby an in-situ test of the laser light path should be possible without detonating the explosive. US 4 917 014 A describes a flat, flexible disc as a carrier, which is provided with a dichroic coating and sandwiched between an explosive charge and a window. To test the laser path, a laser system is operated in a first wavelength range in which the dichroic coating has a reflective effect, while for detonation by the laser system a second wavelength range is used in which the dichroic coating is transparent and allows the laser radiation to reach the explosive charge. US 4 917 014 A describes the use of vacuum coating processes to produce the dichroic coating.

[0017] DE 198 37 839 A1 describes an ignition element with a laser light source. It is described that a part of a laser diode housing facing an explosive can be coated with a substance that improves the absorption of the laser light, particularly the infrared component. DE 198 37 839 A1 describes carbon or black metal oxides as particularly good absorbers of infrared light. As an alternative, DE 198 37 839 A1 describes the admixture of substances to the explosive itself to improve the absorption of the laser light.

[0018] US 6 047 643 A describes a laser detonator or actuator. It is described that a polyimide disc made of Kapton® is provided as a thermal barrier between a lens and an explosive, which is intended to prevent heat from escaping from the reaction zone through the lens.

[0019] A method and device for optically detonating insensitive high-explosives are described in US Pat. No. 3,812,783. A device is described with a housing containing the explosive. The housing has a window with a transparent window pane, the inner side of which is provided with a metal layer. The metal layer is said to be formed from a metal that can be easily vaporized by pulsed laser energy. US Pat. No. 3,812,783 describes a metal layer as being deposited on the surface of a glass window pane.

[0020] US Pat. No. 5,206,455 A describes that a direct detonation of insensitive explosives such as HNS can be achieved using optical energy. US Pat. No. 5,206,455 A describes driving a "flyer" using a plasma generated by optical vaporization of a material, rather than by vaporizing a metal foil using high electrical currents as in an "exploding foil initiator" (EFI). SUMMARY OF THE INVENTION

[0021] Against this background, the object of the invention is to provide an improved way of initiating a secondary explosive, with which modification of the explosive by adding a sensitizing additive can be avoided.

[0022] According to the invention, this object is achieved by an arrangement for initiating an explosive having the features of claim 1 and / or by a manufacturing method having the features of claim 9 and / or by a method for initiating explosives having the features of claim 11.

[0023] Accordingly, an arrangement for initiating an explosive is proposed, wherein the arrangement comprises the explosive, a first layer arranged on the explosive, and a laser beam providing device. The laser beam providing device is configured to provide a laser beam, in particular a laser pulse, in such a way that the laser beam can act on the first layer.

[0024] Furthermore, a method for producing an arrangement for initiating an explosive, in particular an arrangement according to the invention, is proposed, the method comprising: - Providing the explosives; - Arranging a first layer on the explosive; and - Providing a laser beam providing device and setting it up in such a way that a laser beam, in particular a laser pulse, can be provided by means of the laser beam providing device in such a way that the laser beam can act on the first layer.

[0025] Furthermore, a method for initiating explosives is provided, which comprises: - Providing the explosive, wherein a first layer is arranged on the explosive; and - applying a laser beam, in particular a laser pulse, in such a way that the laser beam acts on the first layer, whereby the first layer is heated and vaporized at least in some areas and a shock wave is generated which propagates into the explosive and causes the explosive to detonate.

[0026] One of the insights underlying the invention is that by applying or arranging a first layer and exposing this first layer to a laser beam, mechanical shock waves can be generated in the explosive with the aid of the laser radiation. These shock waves are capable of causing the explosive to react without adding sensitizing substances to the explosive. This is achieved by abruptly heating and vaporizing the first layer in certain areas and forming a plasma stream that generates the shock waves, which then propagate into the explosive.

[0027] The invention can prevent any undesirable effects on the explosive. Furthermore, the considerable effort that can result from changing the explosive composition can be avoided, since the explosive itself can remain unchanged.

[0028] Advantageously, the explosive could be incorporated as part of an existing system, thus avoiding considerable effort, for example, for qualification.

[0029] Furthermore, the invention's use of laser radiation allows for the initiation of the explosive with significantly lower electrical currents and voltages than with conventional foil detonators, allowing for the use of smaller and / or more cost-effective electronic components. The invention thus also enables the creation of a "low-energy detonator," i.e., a detonator requiring less energy to function.

[0030] Furthermore, compared to known foil detonators, the invention enables a significantly simpler definition and design of a detonator without having to modify its explosive. In particular, analytical and hermeneutic design is facilitated.

[0031] Advantageous embodiments and further developments of the invention emerge from the subclaims and from the description with reference to the figures.

[0032] In particular, the first layer is formed with a material with a high absorption capacity for the incoming laser radiation.

[0033] In particular, the first layer can be formed from a high-density material. This allows for high pressure to be achieved upon exposure to the laser beam due to the expansion and resulting plasma of such a material, which is advantageous for the effective initiation of the explosive.

[0034] In the invention, the first layer is formed with a metal, and in this case as a metal foil or a preferably thin metal plate. By using a metal foil or plate as the first layer, a high absorption capacity and absorption rate of the first layer for the incoming laser radiation can be achieved.

[0035] In particular, the first layer, in this case the metal foil or plate, can advantageously be formed from a high-density metal. This makes it possible to effectively transmit shock waves into the explosive with the help of the first layer.

[0036] According to the invention, the metal foil or plate of the first layer is made of steel. Steel is comparatively inexpensive and also has a relatively high density.

[0037] According to the invention, the arrangement further comprises a second layer arranged on the first layer. The second layer is formed as an insulating layer with an at least largely laser-permeable material and covers the first layer at least in part. Furthermore, according to the invention, the laser beam provision device is configured to provide the laser beam, in particular a laser pulse, in such a way that the laser beam can penetrate the second layer and act on the first layer.

[0038] According to the invention, the method for producing an arrangement for initiating an explosive further comprises arranging a second layer on the first layer, wherein the second layer is formed as an insulating layer with an at least largely laser-permeable material and is designed such that it covers the first layer at least in part. Furthermore, the invention provides for the provision of the laser beam provision device and its configuration such that the laser beam, in particular the laser pulse, can be provided by means of the laser beam provision device in such a way that the laser beam can penetrate the second layer and act on the first layer.

[0039] In the method for initiating explosives according to the invention, a second layer, designed as an insulating layer made of an at least largely laser-permeable material, is arranged on the first layer, which second layer covers the first layer at least in part. The laser beam, in particular a laser pulse, is applied to the second layer in such a way that the laser beam penetrates the second layer and acts on the first layer, heating and vaporizing it at least in part, and generating the shock wave.

[0040] A further improvement can be achieved by additionally applying or arranging the second layer, which acts as an insulating layer, to the first layer(s), and by directing the laser beam onto this configuration and acting on the first layer. The insulating layer amplifies and concentrates the shock waves generated during the sudden, localized heating and vaporization of the first layer and the formation of the plasma stream toward the explosive, preventing the shock waves from propagating in the opposite direction away from the explosive. This allows for a high shock wave amplitude and even more effective, efficient initiation of the explosive.

[0041] According to the invention, the second layer is formed with a plastic material, for example a polyimide, such as Kapton ® . Thus, a laser-transparent second layer can be obtained in an effective manner.

[0042] According to the invention, the second layer is formed with a film made of the plastic material. Such a layer is easy to process and apply to the first layer.

[0043] In one embodiment, the second layer can be formed, for example, with a film made of a polyimide, in particular a Kapton film.

[0044] According to the invention, the first layer is applied directly to a surface of the explosive. This can help to effectively transmit the shock waves into the explosive body.

[0045] According to the invention, the first layer is adhesively bonded to the explosive. This allows for a simple and effective attachment of the first layer to the explosive, provided the first layer is formed as a metal foil or metal plate. In this case, no adhesive layer is provided in an area where the laser beam is intended to act on the first layer, in order to avoid a dampening effect of the adhesive; that is, this area is kept free of the adhesive layer.

[0046] According to the invention, the explosive is a secondary explosive. In one embodiment, the explosive is designed as a hexanitrostilbene or contains a hexanitrostilbene. Hexanitrostilbene is also referred to by the abbreviation HNS.

[0047] So-called secondary explosives are significantly less sensitive to external influences than primary explosives. Secondary explosives can therefore be used advantageously and comparatively safely, for example, in a detonator that, upon ignition, can detonate a larger main charge. The invention advantageously offers the possibility of reliable ignition of such secondary explosives, which are relatively difficult to detonate, while simultaneously achieving significant savings in effort and cost and simplifying the design.

[0048] In particular, the explosive can be in the form of hexanitrostilbene IV, so-called HNS IV, or can contain HNS IV.

[0049] For example, in further embodiments, the secondary explosive can be manufactured as a compact or a pellet or a plate made of HNS, in particular HNS IV.

[0050] In one embodiment, the arrangement is designed as a detonator for igniting a main charge or with such a detonator. In a detonator, the relative insensitivity of a secondary explosive can offer advantages, for example, from a safety perspective.

[0051] According to the invention, a secondary explosive is initiated by means of the method for initiating explosives. According to one embodiment, the method for initiating explosives is used, in particular, to initiate a secondary explosive of a detonator for igniting a main charge.

[0052] According to a further embodiment, the laser beam supply device comprises a laser beam generating device and an optical fiber for transmitting a laser beam generated by the laser beam generating device. The installation location of electrical and electronic components, in particular ignition electronics, including the laser beam generating device, can thus be selected independently of the installation location of the detonator and in particular of its explosive. The laser beam or laser pulse used for ignition can be guided via the optical fiber, which can be designed to be flexible if necessary, to the location of the explosive with the first and second layers, depending on the application.

[0053] According to the invention, the laser beam supply device comprises at least one laser diode. In one embodiment, the laser diode is, in particular, a high-power laser diode. The use of a laser diode, in particular a high-power laser diode, as the laser beam generating device enables the provision of a high-power laser beam with minimal installation space requirements.

[0054] In a further embodiment, the arrangement further comprises a lens for focusing the laser beam. This allows the laser radiation to be concentrated on the area of ​​the first layer to be treated, which can improve the evaporation of the first layer in certain areas, the formation of the plasma, and the generation of the shock waves.

[0055] In the method according to the invention for initiating explosives, the laser beam is generated by means of a laser diode.

[0056] In embodiments of the method for initiating explosives, it is provided that the laser beam is generated by means of preferably a high-power laser diode, in particular in pulsed operation, and / or that the laser beam, in particular the laser pulse, is focused by means of a lens and / or that the laser beam, in particular the laser pulse, is guided to the explosive provided with the first layer and the second layer by means of an optical fiber.

[0057] The above embodiments and further developments can be combined with one another as desired, where appropriate. Further possible embodiments, further developments, and implementations of the invention also include combinations of features of the invention not explicitly mentioned above or described below with regard to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0058] Furthermore, it should be noted that, in particular, the embodiments and further developments explained above can each be applied to the arrangement for initiating an explosive, the method for producing an arrangement for initiating an explosive, and the method for initiating explosives. TABLE OF CONTENTS OF THE DRAWING

[0059] The invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures: Fig. 1 shows an arrangement according to a first embodiment of the invention in a schematic representation and schematically illustrates methods in accordance with the first embodiment; Fig. 2 shows an arrangement according to a second embodiment of the invention in a schematic representation and schematically illustrates methods in accordance with the second embodiment; Fig. 3 shows a schematic diagram of an experimental setup; and Fig. Figure 4 shows a schematic of another experimental setup.

[0060] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will be apparent upon review of the drawings. Elements of the drawings are not necessarily shown to scale relative to one another.

[0061] In the figures, identical, functionally identical and acting elements, features and components are provided with the same reference symbols, unless otherwise stated. DESCRIPTION OF EMBODIMENTS

[0062] Fig. 1 schematically shows an arrangement 1 for initiating a secondary explosive 3 according to a first embodiment. In the embodiment of Fig. 1, the explosive 3 is a hexanitrostilbene (HNS), in particular of type HNS IV. The explosive 3 is in Fig. 1 and can be formed, for example, as a pellet-shaped or platelet-shaped compact (not shown in detail).

[0063] The arrangement 1 serves as a detonator for igniting a main charge not shown in the figures.

[0064] Fig. Figure 1 further shows that a first layer 6 is arranged on an outer side of the explosive 3, and a second layer 10 is arranged on the first layer 6. The first layer 6 is thus located between the explosive 3 and the second layer 10, which covers the first layer 6. In other words, the first layer 6 forms a lower or inner material layer, while the second layer 10 forms an upper or outer material layer.

[0065] Here, the first layer 6 is formed as a thin metal foil or a thin metal plate. In the case of the first layer 6 formed as a metal foil or metal plate, the metal foil or plate is made of steel.

[0066] The first layer 6, in this case the metal foil / plate, is applied directly to the outer surface of the explosive 3. The metal foil or metal plate is glued to the outer surface of the explosive 3.

[0067] The second layer 10, which covers the first layer 6, serves as a laser-permeable insulating layer or insulation layer, the function of which will be explained below. The second layer 10 is formed from a material that is essentially permeable or transparent to the laser radiation used in the first embodiment, as described further below.

[0068] The second layer 10 is formed as an additional film applied to the first layer 6, wherein the film is made of a plastic material, in particular of a polyimide, such as Kapton ® .

[0069] The arrangement 1 further comprises a laser beam providing device 15, which comprises a laser beam generating device 16 with one or more high-power laser diodes 17 and a lens 19. Furthermore, the laser beam providing device 15 in the embodiment of the Fig. 1 a high-voltage assembly 36 for supplying the laser beam providing device 15, and a driver assembly 45 which is coupled to the high-voltage assembly 36 and the laser beam generating device 16.

[0070] To initiate the secondary explosive 3 and thus trigger its detonation, a laser pulse is generated which impinges on the arrangement of layers 10 and 6 as a focused laser beam 29. The laser beam 29 penetrates the second, outer layer 10, designed as an insulating layer, essentially without damaging it or being influenced by it in the form of absorption and reflection. After penetrating the second, outer layer 10, the laser beam 29 strikes the first, inner layer 6, acts on it and thus suddenly heats the metal foil or plate with which the first layer 6 is formed. The first layer 6 evaporates at least in part and generates a plasma stream, which in turn generates shock waves that travel through the secondary explosive 3 and cause it to detonate.

[0071] The first layer 6 is thus formed with a material which enables the first layer 6 to absorb the laser radiation with a high absorption rate.

[0072] The second layer or insulating layer 10 causes an amplification of the directional shock waves in the direction of the secondary explosive 3. In other words, the insulating layer 10 advantageously serves to prevent a propagation of the shock waves in an opposite direction, away from the explosive 3, and a resulting reduction in the shock wave amplitude.

[0073] By means of the focused laser beam 29, a kind of hole is thus "drilled" into the first layer 6, for example, with an ultrashort pulse duration, thereby generating the shock or pressure waves, which, with the help of the second layer 10, are directed in a concentrated manner toward the explosive 3 and exert pressure on the secondary explosive 3, present as an HNS compact. By removing material from the first layer 6, shock waves are thus generated, and pressure is exerted on the explosive 3.

[0074] In this way, the explosive 3 does not need to be doped or sensitized with an additive as an optical sensitizer for initiation. Thus, with the arrangement 1 according to Fig. 1, in particular, any undesirable interactions of such an additive for sensitization with the explosive 3 are avoided. Instead, initiation occurs by generating the directed, mechanical shock waves by means of the laser pulse 29 impinging on the layer structure with the layers 6, 10.

[0075] In the case of the above-described bonding of the metal foil or metal plate of the first layer 6 to the outer surface of the explosive 3, the bond is designed such that the adhesive layer is not located in the focus area of ​​the laser beam 29. This prevents absorption of the laser beam by the adhesive layer and the associated loss of power. Undesirable thermal or mechanical influences from the adhesive are not to be expected in this case, given the very rapid generation of the plasma.

[0076] If the second layer 10 is formed as a film, it can also be glued to the first layer 6, for example, in an edge region thereof. Again, an area in the vicinity of the focus of the laser beam 29 is kept free of an adhesive layer. Alternatively, the second layer 10 can be held to the first layer 6 in another way, without gluing.

[0077] The high-voltage assembly 36 of the laser beam providing device 15 in Fig. 1, for example, includes a high-voltage source and a high-voltage ignition capacitor. The ignition capacitor is charged by the high-voltage source. Its discharge is triggered and regulated by the driver module 45. In arrangement 1, it is therefore conceivable in principle to advantageously use an ignition electronics system based on a principle already known as such, so that the effort required for the design of the electronics remains limited.

[0078] In comparison with conventional foil detonators, the laser beam generating device 16 of the Fig. 1, lower voltages and currents are required. For example, an electrical voltage of up to approximately 500 volts and a current of up to approximately 160 amperes may be sufficient for practical, effective operation in the first embodiment.

[0079] Thus, in an exemplary variant, the laser beam generating device 16 is supplied with electrical energy for generating the laser beam 28, 29 at an electrical voltage of no more than approximately 500 volts and an electrical current of no more than approximately 160 amperes. However, other maximum voltage and current values ​​are conceivable.

[0080] Both the lower voltage level and the lower power consumption of the laser diodes 17 compared to, for example, conventional foil detonators are advantageous with regard to semiconductor components such as semiconductor switches or high-voltage capacitors. These components can therefore be designed with a smaller footprint and lower cost, and are easier to obtain and more readily available.

[0081] The optical power of the laser pulse 28, 29 may, for example, be between about 45 watts and about 650 watts, in particular between 125 watts and 500 watts.

[0082] An arrangement 1 according to the first embodiment thus has in particular the following advantages: - Explosive 3 can remain unchanged; - lower electrical voltages and currents are required, which enables lower component costs, smaller component volumes and higher component availability; - if necessary, an already existing ignition electronics can be used, for example in an adapted form, to control the laser beam generating device 16, provided that it is capable of generating a pulse with a suitable current and voltage profile - a complete and complex new development of the electronic arrangement can thus be avoided, the ignition electronics for the arrangement 1 can have a structure that is comparable to an already existing one, for example for a foil detonator (EFI); - a significantly improved analytical and hermeneutic design of a detonator is possible; - a low-energy detonator can be realized due to the significantly lower voltages and currents compared to conventional detonators.

[0083] Laser diodes that are already known per se can be used for the laser beam generating device 16. For example, high-power laser diodes 17, such as high-power infrared laser diodes, such as those used for LiDAR applications, can be used. However, the use of other high-power laser diodes 17 is also conceivable.

[0084] Such laser diodes are available, for example, for a center wavelength of λ centroid ≈ 905 ± 10 nanometers and suitable for pulse widths between 1 nanosecond and 100 nanoseconds with an optical output power of approximately 125 W per channel and a current consumption of approximately 40 amperes. In particular, an optical output power of, for example, up to approximately 650 watts with a current consumption of approximately 60 amperes at λ is also possible. centroid ≈ 905 ± 10 nanometers and pulse widths between 1 ns and 200 ns are conceivable.

[0085] It may be particularly acceptable for the application of the detonator if the laser diode(s) 17 used in the arrangement 1 is / are only capable of generating the one high-power laser pulse required to initiate the explosive 3, or a few such pulses, ie it may be acceptable if the generation of one or fewer such pulses is accompanied by damage to the diode(s) 17, especially since the diode(s) 17 will be destroyed at the latest upon detonation of the main charge.

[0086] By means of the laser beam providing device 15, Fig. 1 generates a high-power laser pulse which introduces a sufficient amount of energy into the explosive 3, causing the explosive 3 to convert and thus detonate. When operating the arrangement 1 according to Fig. 1, the initiation of the explosive 3 is not primarily thermal, although some heat may be introduced into the explosive 3 by the laser pulse 29. Instead, the initiation occurs essentially mechanically by the shock wave propagating into the explosive 3.

[0087] Here, the first layer 6, i.e. the metal foil or metal plate, absorbs the energy of the focused laser pulse, a plasma is formed, and this plasma generates a directed shock wave that runs into the explosive 3.

[0088] In an exemplary implementation of the arrangement 1 and the method for initiating the explosive 3 according to Fig. 1, a pulse duration of the laser pulse of approximately 100 ns with a total optical output power of the laser diode(s) 17 of approximately 125 W and a focus diameter of approximately 0.325 mm can be provided in order to introduce a sufficiently high-energy shock wave into the explosive 3. In another exemplary implementation, also with a pulse duration of 100 ns, a total optical output power of the laser diode(s) 17 of 500 W and a focus diameter of approximately 0.65 mm can be provided. The latter case can be implemented, for example, with four channels of 125 W each.

[0089] Fig. Figure 2 shows an arrangement 61 for initiating an explosive 3 according to a second embodiment. The second embodiment differs from the first embodiment described above only in that a laser beam providing device 55 is used instead of the laser beam providing device 15 of the Fig. 1 is provided. The laser beam supply device 55 is designed essentially in the same way as the laser beam supply device 15, with the exception that the laser beam supply device 55 additionally has an optical waveguide 18. By means of the optical waveguide 18, the high-energy laser pulse generated by the laser beam generation device 16 can be guided to where the secondary explosive 3 with the layers 6 and 10 located thereon is located. In this way, the high-voltage module 36, the driver module 45, as well as the laser diode(s) 17 and possibly other components can advantageously be arranged away from the explosive 3, for example the HNS IV pellet. At the exit of the optical waveguide 18, Fig. 2 the lens 19, which focuses the outgoing laser pulse 29 onto the layer arrangement with the first and second layers 6, 10.

[0090] The second embodiment thus achieves a high degree of flexibility in the spatial arrangement of the detonator components. Laser initiation decouples the installation location of the ignition electronics from that of the secondary explosive 3, since the laser energy can be transmitted with virtually no loss via the optical fiber 18.

[0091] In addition to what has been described above, the arrangement 61 according to the second embodiment is designed in the same way as the arrangement 1 according to the first embodiment.

[0092] The Fig. 1 and Fig. 2 further illustrate embodiments of methods for producing an arrangement 1 or 61 for initiating an explosive 3, in which in each case the first layer 6 is arranged on the secondary explosive 3, the second layer 10 is arranged on the first layer 6 in such a way that the second layer 10, as an insulating layer, covers the first layer 6 at least in regions, and the laser beam providing device 15 or 55 is provided and configured as described above.

[0093] In addition, the Fig. 1 and Fig. 2 embodiments of methods for initiating secondary explosives 3, wherein the laser beam 29 is applied to the second layer 10 as a laser pulse or impinges upon it in such a way that the laser beam 29 penetrates the second, outer layer 10, essentially unhindered and without damaging it, and acts on the first, inner layer 6. As a result, the first layer 6 is heated and vaporized at least in certain regions, and a shock wave is generated that travels into the explosive 3 and detonates the explosive 3.

[0094] As described above, the arrangements 1, 61 can be designed computationally in an improved manner. For example, for experimental verification, a comparison can additionally be made between a foil detonator (EFI) of conventional design and an arrangement 1, 61 according to the exemplary embodiments described above.

[0095] For this purpose, a steel plate or foil with a thickness in the micrometer range, for example, can be bombarded with the laser pulse 29 on the one hand, and with the flyer of an EFI on the other. Pressure waves then propagate in the steel plate / foil, and the pressure profiles can be recorded using a piezo signal generator. The pressure peak amplitudes can provide a direct comparison of the two technologies. In addition, the effects of varying the focus diameter and steel plate thickness can be reproduced. Advantageously, the use of explosives can be avoided in such experiments, thereby reducing costs and effort, while still allowing the achieved pressure peak amplitude to be compared with the amplitude of the shock waves 91 required for initiation. Experimental setups are shown schematically for arrangements 1 or 61 in Fig. 3 and in the case of the EFI in Fig.4, schematically showing the steel plate / foil 66, an insulating layer 67 arranged on the steel plate / foil similar to the second layer 10, a piezo signal generator 68, and an oscilloscope 70. Reference numeral 78 denotes a schematic EFI, and reference numeral 91 schematically depicts pressure waves.

[0096] In the embodiments described above, an insulating layer 10 is provided in each case, which concentrates the shock waves in the direction of the explosive 3 in an advantageous and useful manner for a reliable initiation of the explosive 3.

[0097] Although the invention has been fully described above using preferred embodiments, it is not limited thereto but can be modified in many ways. List of reference symbols 1 arrangement 3 Explosives 6 first layer 10 second layer 15 Laser beam delivery device 16 Laser beam generating device 17 laser diode 18 optical fibers 19 lens 28 laser beam 29 focused laser beam 36 High-voltage assembly 45 Driver assembly 55 Laser beam delivery device 61 Arrangement 66 steel plate 67 Insulation layer 68 piezo signal generators 70 Oscilloscope 78 EFI 91 pressure waves

Claims

[1] Arrangement (1; 61) for initiating an explosive (3), comprising the explosive (3), wherein the explosive (3) is a secondary explosive; a first layer (6) arranged on the explosive (3), wherein the first layer (6) is applied directly to a surface of the explosive (3), wherein the first layer (6) is designed as a metal foil or metal plate glued onto the explosive (3), wherein the metal foil or metal plate is made of a steel; a second layer (10) arranged on the first layer (6), wherein the second layer (10) is formed as an insulating layer with an at least largely laser-permeable material and covers the first layer (6) at least in regions, wherein the second layer (10) is formed with a film formed with a plastic material; and a laser beam providing device (15; 55) which is designed to provide a laser beam (28, 29), in particular a laser pulse, in such a way that the laser beam (29) can penetrate the second layer (10) and act on the first layer (6), wherein the laser beam providing device (15; 55) comprises at least one laser diode (17); wherein the second layer (10) is formed such that the laser beam (29) can penetrate the second layer (10) substantially without damaging the second layer (10) or being influenced by it in the form of absorption and reflection; wherein the second layer (10) is designed to amplify directional shock waves, which are generated during at least partial heating and evaporation of the first layer (6) by the action of the laser beam (29) on the first layer (6), in the direction of the explosive (3) and to prevent propagation of the shock waves in an opposite direction, away from the explosive (3), and a resulting reduction in the shock wave amplitude; and wherein the bonding of the metal foil or metal plate to the explosive (3) is carried out in such a way that an area in which the action of the laser beam (29) on the first layer (6) is intended is kept free of an adhesive layer. [2] Arrangement according to claim 1, characterized bythat the film of the second layer (10) is made of the plastic material, the second layer (10) is designed as the film made of the plastic material and the film made of the plastic material is glued to the first layer (6), the gluing of the metal foil or metal plate to the explosive (3) is carried out in such a way that an area of ​​a focus of the laser beam (29) is kept free of the adhesive layer, and the gluing of the film of the second layer (10) to the first layer (6) is carried out in such a way that an area in the vicinity of the focus of the laser beam (29) is kept free of an adhesive layer. [3] Arrangement according to claim 1 or 2, characterized by that the film with which the second layer (10) is formed is made of a polyimide. [4] Arrangement according to at least one of the preceding claims, characterized bythat the explosive (3) is designed as a hexanitrostilbene or contains a hexanitrostilbene. [5] Arrangement according to at least one of the preceding claims, characterized by that the arrangement (1) is designed as or with a detonator for igniting a main charge. [6] Arrangement according to at least one of the preceding claims, characterized by that the laser beam providing device (55) has a laser beam generating device (16) and an optical fiber (18) for transmitting a laser beam (28) generated by the laser beam generating device (16). [7] Arrangement according to at least one of the preceding claims, characterized by that the laser diode (17) is a high-power laser diode. [8] Arrangement according to at least one of the preceding claims, characterized by that the arrangement (1; 61) further comprises a lens (19) for focusing the laser beam (28). [9] Method for producing an arrangement (1; 61) for initiating an explosive (3), in particular an arrangement (1; 61) according to one of the preceding claims, comprising: Providing the explosive (3), wherein the explosive (3) is a secondary explosive; Arranging a first layer (6) on the explosive (3), wherein the first layer (6) is formed as a metal foil or metal plate made of steel and is glued onto the explosive (3), wherein the first layer (6) is applied directly to a surface of the explosive (3); Arranging a second layer (10) on the first layer (6), wherein the second layer (10) is formed as an insulating layer with an at least largely laser-permeable material and is designed such that it covers the first layer (6) at least in regions, wherein the second layer (10) is formed with a film formed with a plastic material; and Providing a laser beam providing device (15; 55) and setting it up in such a way that a laser beam (28, 29), in particular a laser pulse, can be provided by means of the laser beam providing device (15; 55) in such a way that the laser beam (29) can penetrate the second layer (10) and act on the first layer (6), wherein the laser beam providing device (15; 55) comprises at least one laser diode (17); wherein the second layer (10) is formed such that the laser beam (29) can penetrate the second layer (10) substantially without damaging the second layer (10) or being influenced by it in the form of absorption and reflection; wherein the second layer (10) is designed to effect an amplification of directional shock waves, which are generated during at least partial heating and evaporation of the first layer (6) by the action of the laser beam (29) on the first layer (6), in the direction of the explosive (3) and to prevent a propagation of the shock waves in an opposite direction, away from the explosive (3), and a resulting reduction in the shock wave amplitude; and wherein for the bonding of the metal foil or metal plate to the explosive (3), the bonding is carried out in such a way that an area in which the action of the laser beam (29) on the first layer (6) is intended is kept free of an adhesive layer. [10] Method according to claim 9, characterized by that the film of the second layer (10) is made of the plastic material and is glued to the first layer (6), and that the gluing of the metal foil or metal plate to the explosive (3) and the gluing of the film of the second layer (10) to the first layer (6) are each carried out in such a way that a region of a focus of the laser beam (29) is kept free of an adhesive layer. [11] A method for initiating a secondary explosive (3), comprising: Providing the explosive (3), wherein a first layer (6) is arranged on the explosive (3) and the first layer (6) is applied directly to a surface of the explosive (3), wherein the first layer (6) is formed as a metal foil or metal plate made of steel and glued onto the explosive (3), and wherein a second layer (10) is arranged on the first layer (6) and is formed as an insulating layer with an at least largely laser-permeable material, which second layer (10) covers the first layer (6) at least in regions, wherein the second layer (10) is formed with a foil formed with a plastic material; and Applying a laser beam (28, 29), in particular a laser pulse, such that the laser beam (29) acts on the first layer (6), whereby the first layer (6) is heated and vaporized at least in some areas and a shock wave is generated which propagates into the explosive (3) and detonates the explosive (3), wherein the laser beam (28, 29) is generated by means of a laser diode (17) and wherein the laser beam (28, 29), in particular a laser pulse, is applied to the second layer (10) such that the laser beam (29) penetrates the second layer (10) and acts on the first layer (6) for its at least partial heating and vaporization and the generation of the shock wave, wherein the laser beam (29) penetrates the second layer (10) substantially without damaging the second layer (10) or being influenced by it in the form of absorption and reflection, and wherein the second layer (10) causes an amplification of the directional shock waves in the direction of the explosive (3) and prevents a propagation of the shock waves in an opposite direction, away from the explosive (3), and a resulting reduction in the shock wave amplitude; and wherein the bonding of the metal foil or metal plate to the explosive (3) is carried out in such a way that an area in which the action of the laser beam (29) on the first layer (6) is intended is kept free of an adhesive layer. [12] Method according to claim 11, characterized by that the secondary explosive (3) initiated by the method is a secondary explosive of a detonator for igniting a main charge. [13] Method according to claim 11 or 12, characterized by , that the laser diode (17) by means of which the laser beam (28, 29) is generated is a high-power laser diode and / or the laser beam (28, 29) is generated by means of the laser diode (17), in particular in pulsed operation and / or that the laser beam (28), in particular laser pulse, is focused by means of a lens (19) and / or that the laser beam (28), in particular laser pulse, is guided to the explosive (3) provided with the first layer (6) and the second layer (10) by means of an optical waveguide (18). [14] Method according to one of claims 11 to 13, characterized bythat the film of the second layer (10) is made of the plastic material, the second layer (10) is designed as the film made of the plastic material and is glued to the first layer (6), the gluing of the metal foil or metal plate to the explosive (3) is carried out in such a way that an area of ​​a focus of the laser beam (29) is kept free of the adhesive layer, and the gluing of the second layer (10) to the first layer (6) is carried out in such a way that an area in the vicinity of the focus of the laser beam (29) is kept free of an adhesive layer.

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