AT523319A1 - Method and system for generating an ion or electron beam - Google Patents

Abstract

In a method and a system for generating an ion or electron beam, the following elements are provided: a carrier (1) for receiving a magnetic powdery material in a conductive or conductive liquid (2), a device for providing and applying a Magnetic field to the magnetic material to generate tips (3) in the magnetic material, at least one electrode (4) at a distance from the magnetic material or the carrier, and a device for applying an electric field between the magnetic material and the liquid and the electrode (4) for generating an electric field at the tips (3) of the magnetic material and the liquid for emitting ions or electrons.

Description

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The present invention relates to a method and a system for generating an ion or electron beam.

Such an ion beam can be used, for example, as a drive for a space probe, a satellite or the like, while an electron beam is used, for example, in an electron microscope or the like.

Common methods and systems for implementing or using such sources include using a structure, for example in the form of a capillary, a needle, or an array of such elements. However, the process of producing such structures is very expensive and complicated and requires several steps, such as the production of a mold, a molding process and a needle etching process. Steps of this kind are usually difficult to implement, particularly in the case of two-dimensional arrays or fields, with the structures generated additionally being partially fragile, static and thus not adaptable to different circumstances. Embodiments of such ion or electron sources can be found, for example, in FR 2 912 836 A1, US Pat. No. 3,122,882 A, US 2010/0251690 A1 or AT-B 512 617.

In addition, WO 2014/134386 A1 discloses the generation of an electrospray from a ferrofluid, in which case so-called Rosensweig instabilities are responsible for the formation of peaks in a ferrofluidic liquid. Such formed tips in a ferrofluidic liquid have a rounded or blunt shape of elevations, the formation of Taylor cones or Taylor cones, which are generated in the fluid by applying an electric field, is also known from this literature reference, see above that through an attraction to the

Counter electrode forms a sharper tip.

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The present invention aims to provide a method and a system for generating an ion or electron beam, it being possible to provide an ion or electron beam with a simplified outlay compared to known embodiments using needle-shaped emitters or arrays In particular, a simple adaptation of the configuration of such an electron or ion beam to different conditions is also possible.

To solve these problems, a method for generating an ion or electron beam essentially comprises the following steps:

- Providing a magnetic powdery material in a conductive or conductive liquid in a carrier,

- applying a magnetic field to the magnetic material to generate peaks in the magnetic material,

- providing at least one electrode at a distance from the magnetic material or the carrier, and

- applying an electric field between the magnetic material and the liquid and the electrode to create an electric field at the tips of the magnetic material and the liquid to deliver ions or electrons.

By providing a magnetic powdery material in a conductive or conductive liquid in a carrier and applying a magnetic field and an electric field to the magnetic material, tips can be generated in the magnetic material, the configurations of such tips or needle-like configurations of the magnetic Material can be adapted to the application or intended use in accordance with the applied magnetic field and electric field. As explained above, it is

known for having seen magnetic materials in one

Leaking or conductive liquid by applying a "

Magnetic field and an electric field pointed or needle-like

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produce like structures, whereby the use of a magnetic powdery material in a conductive or conductive liquid when a magnetic field and an electric field is applied, so-called Taylor cones or Taylor cones, which sharp points in such a magnetic material and are produced according to the invention the liquid for subsequent release of ions or electrons available. In this context, it is proposed according to the invention that at least one electrode is additionally provided at a distance from the magnetic material or the carrier, so that by additionally applying an electric field between the magnetic material in the liquid and the electrode to generate an electric field at the Tips of the magnetic material and the liquid are released according to the polarity of the electric field ions or electrons. It should be pointed out here again that the tips obtained in this way cannot be compared with the so-called Rosensweig instabilities which are generally found in ferrofluid or ferrofluidic fluids, as discussed at the beginning. Such Rosensweig instabilities are rounded or blunt elevations, while the tips, which can be obtained by using magnetic powdery material, are sharper, which results in a higher electric field at the tip and lower voltages which lead to a production of Taylor cones are required.

By providing a corresponding magnetic field and electric field, it is possible, according to requirements, to have a large number of configurations of the needles or tips, for example by varying the magnetic field strength and / or electrical field strength and / or the shape of the magnetic field and by adaptation the magnetic powder "material and the liquid as well as the conductive"

or to provide conductive liquid. Like that

the magnetic powdery material is essentially a framework, while the conductive or conductive liquid is non-magnetic and represents the component that is ionized and released or expelled.

In this context, according to a preferred embodiment, it is proposed that the magnetic powdery material be formed from ferromagnetic materials such as iron, nickel or cobalt, for example. The use of such ferromagnetic materials enables the tips to be achieved or formed when a magnetic field is applied, and the tips are used to create a high electrical field to achieve correspondingly high rates of ions or electrons. When using ferromagnetic materials, iron powder, for example, can be preferred, in particular because of the lower toxicity of such a material compared to nickel and cobalt.

To achieve correspondingly fine needle-like or pointed structures in the magnetic powdery material contained in a conductive or conductive liquid when a magnetic field is applied, it is proposed according to a further preferred embodiment that the magnetic powdery

Material mean particle dimensions in the nanometer range

to micrometers, in particular about 5 nm to about 150 µm. As a conductive or conductive liquid or liquid component, which serves for wetting the magnetic powdery material which is dispersed or distributed therein, it is proposed according to a further preferred embodiment that the conductive or conductive liquid of a liquid metal, a ionic liquid, a liquid which is capable of influencing electric fields, a reconfigurable ferromagnetic liquid

Liquid or the like. Is formed.

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In general, a substance which is suitable for an emission of ions and / or electrons can be used as the conductive or conductive liquid.

The following liquids can preferably be used as ionic liquids: 1-ethyl-3-methylimidazole tetrafluoroborate, 1- (2-hydroxyethyl) -3-methylimidazole dicyanamide, 1-butyl-1-methylpyrrolidine dicyanamide, 1-butyl-3-methylimidazole hexafluorophosphate , 1,2-dimethyl-3-propylimidazole-tricyanmethide, 1-ethyl-2-methylpyrazole-tetrafluoroborate, allyimethylimidazole-dicyanamide, and 1-butyl-3-methylimidazole-dicyanamide.

For a particularly good use of the powdery magnetic material, it is also proposed that the liquid metal be formed by an alloy that is liquid at ambient temperature, for example gallium-indium-tin, as corresponds to a further preferred embodiment of the method according to the invention. By operating at ambient temperatures, rapid oxidation is avoided and problems which occur due to the use of, for example, hydrochloric acid as a flux at high temperatures, can also be avoided.

According to a further preferred embodiment, it is proposed that the magnetic field be provided by a permanent magnet or an electromagnet. In this way, it is possible to achieve the formation of roughly evenly distributed sharp points or needles. A desired distribution of such sharp points or needles is obtained by a desired arrangement of the magnetic field.

In order to facilitate or support the generation and distribution of the peaks, it is proposed according to a further preferred embodiment that the magnetic field is changed in terms of time and / or location and / or mechanical vibrations are applied. For this purpose, for example, a piezo-electric

tric actuator can be used.

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To achieve the desired sharp points or needles, the procedure is also such that the strength of the magnetic field is selected in a range from 50 uT to 3.5 T, in particular from 2 mT to 500 mT, as in a further preferred embodiment of the invention Procedure.

When a corresponding high voltage is applied to the electrode and the powdered magnetic material and the liquid, correspondingly high electric field strengths are generated at the tips or needles, where the conductive liquid with the powdered magnetic material contained therein has well-defined conical shapes at the tips forms which, as mentioned above, are known as Taylor cones. In this context, it is proposed according to a further preferred embodiment that the applied voltage for generating the electric field is selected in a range from 250 V to 1.5 MV, in particular from 1000 V to 180 kV, preferably 3000 V to 25 kV. The selection of the voltages generally depends on the geometry of the system and on the preferred operating points and, as stated above, can vary within a wide range of values, generally a voltage difference between the emitter (magnetic powder + liquid conductive metal) and the extractor (negative or counter electrode) of a few kilovolts, for example about 15 kV, is sufficient to start an emission of ions.

In this way, depending on the polarity of the electric field, ions or electrons are emitted from the tips of the TaylorCones.

In order to achieve the objects mentioned at the beginning, according to the invention, a system for generating an ion or electron beam essentially comprises:

- a carrier for holding a magnetic powdery material in a conductive or conductive liquid-

ability,

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- A device for providing and applying a magnetic field to the magnetic material for generating peaks in the magnetic material,

- At least one electrode at a distance from the magnetic material or the carrier, and

a device for applying an electric field between the magnetic material and the liquid and the electrode for generating an electric field at the tips of the magnetic material and the liquid for the delivery of ions or electrons.

In this way, it is possible in a simple and reliable manner by providing a magnetic powdery material in a conductive liquid and by applying a magnetic field and an electric field to the magnetic material and the liquid, correspondingly well-defined peaks in the magnetic material and the liquid To make available, so that a defined release of ions or electrons can be achieved by additionally providing an electrode with the application of an electric field at the tips of the magnetic material and the liquid.

According to a preferred embodiment, it is proposed here that the device for providing a magnetic field is formed by a permanent magnet or an electromagnet.

To adapt to possibly different circumstances while providing different configurations of the arrangement of the tips or needles of the magnetic powdery material, it is also proposed that a device for generating a mechanical application, in particular a vibration or oscillation, to the magnetic material, for example a piezoelectric actuator, and / or a device for changing,

of the magnetic field is (are) provided, as is

preferred embodiment of the system according to the invention.

In particular, depending on the polarity of the electric field to be applied between the electrode and the tips of the magnetic powdery material which is distributed or absorbed in the conductive or conductive liquid, the method according to the invention and the system according to the invention can be used as a drive for a space probe, use a satellite or the like when generating ions.

If the polarity of the electric field is correspondingly reversed with the release of electrons, the method according to the invention and the system according to the invention can be used, for example, in an electron microscope.

An emission of electrons can also be increased, for example, by exposing the tips to electromagnetic radiation, for example, but not limited to UV light, heat.

The invention is explained in more detail below with reference to the exemplary embodiments shown schematically in the accompanying drawing. In this show:

1 shows a schematic view of a first embodiment of a system according to the invention for carrying out the method according to the invention for generating an ion beam;

FIG. 2 shows, in a representation similar to FIG. 1, a schematic view of a modified embodiment of a system according to the invention for carrying out the method according to the invention for generating an electron beam;

3a to 3c show detailed views of a carrier of the system according to the invention with a magnetic powdery material in a conductive or conductive liquid with the formation of peaks under the influence of a magnetic field; and

4a to 4c further modified embodiments of the system according to the invention with different devices for

Generating and / or influencing the magnetic field.

In Fig. 1, 1 denotes a carrier on which a magnetic powdery material is arranged in a conductive or conductive liquid 2, wherein, as will be discussed below, the magnetic powdery material by applying a magnetic field and an electric field Material 2 forms a plurality of needles or tips 3, as will also be discussed in detail below, in particular with reference to FIG. 3.

In addition to the carrier 1, an electrode 4 is provided at a distance therefrom and at a distance from the tips 3.

By applying a high voltage HV of positive polarity to the carrier 1 and applying a high voltage HV of negative polarity to the electrode 4, ions are emitted from the liquid by the tips 3 of the mixture formed by the magnetic powdery material and the conductive liquid, so that through the release of the ions marked +, a thrust corresponding to the arrow 5 is exerted on a device containing the carrier 1 and the electrode 4.

In this way, the system shown in FIG. 1 can be used, for example, as an ion drive for a space probe, a satellite or the like.

In this context it is noted that the electrode 4 can theoretically also be at ground potential or even be positive, a necessary condition being that the difference between the voltage applied to the ion-emitting material and the electrode is positive have to be.

If the voltage applied to the ion-emitting material were negative, the ions would immediately afterwards again impinge on the carrier 1, so that generally the voltage applied to the ion-emitting material is positive.

The magnetic one is responsible for the release of the ions

powdery material a framework, especially for training

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of the tips 3, while the liquid, which is non-magnetic, is ionized and releases ions.

In the embodiment shown in FIG. 2, a magnetic powdery material is again provided in a conductive or conductive liquid 12 on a carrier 11, needles or tips 13 being formed by applying a magnetic field. Furthermore, an electrode 14 is provided at a distance from the carrier 1L and the powdery magnetic material arranged thereon in the conductive liquid.

When a high voltage HV is applied with the polarity reversed to that of the configuration according to FIG. 1, in the system shown in FIG.

Such an arrangement as shown in FIG. 2 can be used, for example, in an electron microscope.

Electron emission can also be used for a space probe or a satellite, such emission of electrons being used, inter alia, for charge compensation or for controlling or regulating the charge of the satellite.

In FIG. 3, in the individual representations according to FIGS. 3a to 3c, essential details for the formation of the tips 3 or 13 in the magnetic powdery material in a conductive liquid 2 or 12 are shown.

From Fig. 3a it can be seen that the carrier 1 or 11 is formed, for example, directly by a magnet, for example a permanent magnet or an electromagnet, with N and S poles of such a magnet being indicated. With such an orientation of the magnet, field lines indicated schematically with 6 are generated by the magnet.

By arranging magnetic powdery material in a conductive liquid, which as in

Fig. 1 and 2 is designated by 2 and 12, respectively, on the carrier 1 and

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11, which contains a magnet or is formed directly by it, the tips 3 and 13 are formed along the magnetic field lines 6.

A formation of very thin or fine needles or points 3 or 13 is supported in addition to the provision of the magnetic field by the application of a high voltage HV, so that a formation of a very fine point 3 or 3c shown in an enlarged detail of FIG 13 can be achieved, the uppermost part of the tip usually being referred to as Taylor cone or Taylor cone.

By appropriately setting and / or spatial design of the magnetic field in the carrier 1 or 11, it is possible to adapt the configuration and the number of tips 3 or 13 formed in accordance with the requirements.

4 schematically shows different or modified embodiments of a carrier for receiving a magnetic powdery material in a conductive or conductive liquid to form the tips of the magnetic powdery material and the conductive liquid, again denoted by 3 in the previous figures formed mixture for the emission of ions or electrons shown.

In the embodiment shown schematically in FIG. 4a, a permanent magnet 21 is used as the carrier, which is coupled to a piezo-like actuation device 22, the piezo-actuation device 22 for changing or influencing the magnetic field, in particular for changing the configuration of the tips 3 can be used.

In the embodiment shown in FIG. 4b, an electromagnet is used for the carrier 23, with a coil core made of a ferromagnetic material being indicated at 24 and a coil winding being indicated at 25.

In addition, in the embodiment shown in Fig. 4c

Approximate form for a carrier 26 is a combination of one

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Electromagnet, the essential elements of which are again denoted by 23 and 24, and a piezo actuator 22 is formed.

Instead of a piezo actuating element 22, an actuating element similar to a vibrator, which is based, for example, on eccentrically suspended rotating masses, can be used to achieve mechanical loading.

The frequencies used for such a loading of a carrier formed, for example, by a permanent magnet 21 or an electromagnet 23, can be 2.5 MHz in the case of the piezo actuating element or 50 Hz in the case of a mechanical vibrator.

The following material combinations can be used as materials for the magnetic powdery material in a conductive or conductive liquid, as this is designated in the preceding figures with 2 or 12.

1. As the magnetic metal powder, cobalt can be used in combination with the ionic liquid 1-ethyl-3-methylimidazole tetrafluoroborate. The following parameters can be selected for the magnetic field, the electrical voltage and the particle or particle size:

800 mT, 2,500 V, 900 nm

2. The following configuration can also be used for the combination of the magnetic powdery material and the conductive or conductive liquid:

A powder made of an alloy between iron, aluminum, copper, cobalt, titanium and nickel (similar to Alnico), the liquid metal Galinstan, using the following parameters for the magnetic field strength, the electrical voltage and the typical particle size:

900 mT, 18,500 V, 10 µm

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Claims (14)

+ - 13 - claims 1. A method for generating an ion or electron beam, comprising the following steps: - Providing a magnetic powdery material in a conductive or conductive liquid (2, 12) in a carrier (1, 11), - applying a magnetic field to the magnetic material to generate tips (3, 13) in the magnetic material, - providing at least one electrode (4, 14) at a distance from the magnetic material or the carrier (1, 11, 21, 23), and - Application of an electric field between the magnetic material and the liquid and the electrode (4, 14) to generate an electric field at the tips (3, 13) of the magnetic material and the liquid to give off ions (+) or electrons (- ). 2. The method according to claim 1, characterized in that the magnetic powdery material is formed from ferromagnetic materials such as iron, nickel or cobalt. 3. The method according to claim 1 or 2, characterized in that the magnetic powdery material medium particle dimensions in the range from nanometers to micrometers, in particular about 5 nm to about 150 µm. 4. The method according to claim 1, 2 or 3, characterized in that the conductive liquid (2, 12) of a liquid metal, an ionic liquid, a liquid which is capable of influencing electrical fields, a reconfigurable one ferromagnetic liquid or the like. Is formed. _ 5. The method according to claim 4, characterized in that the liquid metal is from a liquid at ambient temperature Alloy, for example gallium-indium-tin, is formed. * - 14 - 6. The method according to any one of claims 1 to 5, characterized in that the magnetic field is provided by a permanent magnet (21) or an electromagnet (23). 7. The method according to any one of claims 1 to 6, characterized in that the magnetic field is changed in terms of time and / or location and / or mechanical vibrations are applied. 8. The method according to any one of claims 1 to 7, characterized in that the strength of the magnetic field is selected in a range from 50 uT to 3.5 T, in particular from 2 mT to 500 mT. 9. The method according to any one of claims 1 to 8, characterized in that the applied voltage for generating the electric field is selected in a range from 250 V to 1.5 MV, in particular from 1000 V to 180 kV, preferably 3000 V to 25 kV will. 10. A system for generating an ion or electron beam, comprising: - a carrier (1, 11, 21, 23) for holding a magnetic powdery material in a conductive liquid (2, 12), - A device for providing and applying a magnetic field to the magnetic material for generating tips (3, 13) in the magnetic material, - at least one electrode (4, 14) at a distance from the magnetic material or the carrier (1, 11, 21, 23), and - A device for applying an electric field between the magnetic material and the liquid and the electrode (4, 14) for generating an electric field at the tips (3, 13) of the magnetic material and the liquid to release ions (+) or Electrons (-). 11. System according to claim 10, characterized in that the device for providing a magnetic field of a Permanent magnet (21) or an electromagnet (23) is formed. - 15 - 12. System according to claim 10 or 11, characterized in that in addition a device for generating a mechanical application, in particular a vibration or oscillation on the magnetic material, for example a piezoelectric actuating device (22), and / or a device for changing the magnetic field is (are) provided. 13. Use of a method and a system for generating an ion or electron beam according to one of the preceding claims as a drive for a space probe, a satellite or the like. 14. Use of a method and a system according to one of claims 1 to 12 in an electron microscope or like Korneuburg, December 11, 2019 FOTEC Fökrschungs- und Technolpfgietransfer GmbH