RU207660U1 - MULTIAPERTURE MATCHING CHANNEL WITH RADIAL COMPRESSION OF ION BEAMS - Google Patents

Abstract

The multi-aperture matching channel with radial compression of ion beams is effective for use in multichannel ion accelerators, the injection into which is performed from a plasma with a low density of the ion component and a large surface area of ion emission. The originality of the proposed technical solution lies in the fact that the dimensions of the inlet apertures of the drift tubes of individual channels of the utility model exceed the geometric dimensions of the apertures at its outlet. This allows the selection of ions for acceleration in each separate channel of the multichannel accelerating RF system from the plasma surface, the area of which exceeds the corresponding size of the channel of the accelerating RF system, thereby increasing the total surface area of the ion extraction for acceleration. The applied method of electrostatic focusing of ions by an electric field in the accelerating gaps between adjacent drift tubes, which in these gaps have the same aperture sizes, synchronously decreasing towards the output of the utility model, provides effective radial compression of the ion beam, which, together with the general direction of the electric field in individual channels , allows you to extract ions from the plasma of various IRs and reduce their losses during transportation and when entering the channels of the accelerating RF system. The factors listed above contribute to an increase in the total current of ion beams accelerated in a multichannel accelerator. 4 fig.

Description

The utility model relates to the field of multichannel charged particle accelerators and can be used to accelerate ions in plasma technology installations and other nuclear technology devices.

Ion sources (IS) with a large atomic mass are characterized by the generation of plasma with a low content of particles with a high electric charge. An increase in the intensity of a beam of such ions accelerated in an accelerator is achieved by selecting them into the acceleration mode from a plasma with a large emission surface area. In these cases, to increase the current of the accelerated beam, multichannel accelerating high-frequency (HF) systems are used (Davis R, Morgan O, Stuart L. Instruments for Scientific Research, 1972, No. 2, p. 99). The use of multi-aperture matching channels in multichannel accelerators makes it possible to increase the selection of ions in the acceleration mode from the plasma. In the known designs of multi-aperture matching channels, the area of the apertures through which the ions are extracted from the plasma and transported to the HF accelerating systems does not exceed the area of the apertures of the accelerating channels of the HF systems, which is limited by factors known in accelerator technology.

Known multi-aperture matching channel for a multibeam ion accelerator (Kondrat'ev B.K., Kushin V.V., Plotnikov S.V. and others, Injector for a multibeam proton accelerator. PTE 2004. No. 4, pp. 5-13). The disadvantages of this channel are the low value of the ion beam accelerated in the accelerator, which is caused by the small area of the apertures that select ions from the plasma.

A multi-aperture ion-optical system is known, consisting of several shells, in which coaxially located apertures of the same diameter are made and an electric voltage with different values of electrical potentials is applied to the shells (Kondrat'ev B.K., Turchin A.V., Turchin V.I., and others. Modernization of the injector of the multibeam proton accelerator, PTE 2009, No. 4, pp. 29-41). The disadvantages of this device are in the limited area of selection of ions from the plasma and a small value of the current of the accelerated ion beam.

The closest analogue to the proposed technical solution, adopted as a prototype, is a multi-aperture ion injector with transverse convergence of beams (E.P. Bogolyubov, V.T. Bobylev, V.A. deuteron injection systems, Proceedings of the interdisciplinary scientific and technical conference. Moscow, 2003, May 26-30, pp. 137-144.). In this injector, which makes it possible to inject ions for acceleration taken from a plasma with a large emission surface area, spherical shells are installed in which coaxial apertures of the same diameter are made, converging to the drift tubes of the accelerating channels of the RF accelerator system. An electrical potential difference is created between the shells.

The disadvantages of the closest analogue consist in weak focusing of ion beams in the space between the shells and in the fact that the area of the apertures of the matching channels in the region of ion selection from the plasma does not exceed the area of the apertures of the accelerating channels of the RF system of the accelerator, which reduces the value of the ion beam current accelerated in it.

The technical problem is the need to increase the ion beam current.

The technical task of the proposed utility model is the creation of a multi-aperture matching channel with an increased current of ion beams.

When solving a technical problem, it was ensured that not only an increase in the current of ion beams was achieved, but also the possibility of focusing and radial compression of ions inside each individual channel by an axially symmetric electric field in the gaps between adjacent drift tubes with a varying aperture area and a change in the direction of movement of the ion beam in space along the trajectory of each individual channel with the same electric field, which is the technical result of the proposed utility model.

Achievement of the technical result is ensured by the creation of a multi-aperture matching channel, which makes it possible to increase the current of ions accelerated in the accelerator by expanding the total area of extraction of ions from the plasma, by increasing the area of extraction of ions from each channel, with the possibility of matching the position in space and the transverse dimensions of the ion beams at the exit of these channels with the sizes and positions of the corresponding apertures of the drift tubes of the accelerating HF system.

A multi-aperture matching channel with radial compression of ion beams is proposed, consisting of a body, shells with coaxially located apertures converging to its central longitudinal axis, and the diameter of these apertures decreases as they converge and hollow drift tubes are installed in the apertures of a conical shape, made in this way, so that the inlet diameter of each drift tube is greater than its outlet diameter, which in turn is equal to the inlet diameter of each subsequent drift tube, and the body and shells are electrically isolated from each other and electrically connected to separate power supplies.

A distinctive physical property of the proposed utility model from the closest analogue, which appeared as a result of the proposed design of shells with drift tubes in apertures, and ensuring the achievement of the claimed technical result, is the possibility of focusing and radial compression of ions inside each separate channel by an axially symmetric electric field in the gaps between adjacent tubes drift with a changing area of apertures and changes in space of the direction of motion of the ion beam along the trajectory of each individual channel by the same electric field.

The claimed technical result in a multi-aperture matching channel with radial compression of ion beams, consisting of shells with coaxial apertures converging to its central longitudinal axis, is achieved by their proposed original design. Namely, the diameter of the apertures in the shells decreases as they converge to the outlet of this device, and hollow drift tubes are installed in these apertures of a conical shape, made in such a way that the inlet diameter of each drift tube is greater than its outlet diameter, which in turn , is equal to the inlet diameter of each subsequent drift tube. All shells are electrically isolated from the body and from each other and connected to separate power supplies.

In contrast to the known analogs, the proposed utility model has new properties due to the proposed original technical solutions. Namely, the force of electrostatic focusing of the ion beam appears in each channel by the electric field lines "sagging" to its central longitudinal axis, which makes it possible to focus and compress the ion beam as it moves from the entrance to its exit from the channel. This contributes to an increase in the ion density of the beam injected into the corresponding channel of the accelerating RF system by each separate channel of the multi-aperture matching channel with radial compression of the ion beams. The general trajectory of the direction in space of the lines of force of the electric field in each separate channel of this useful model allows the ion beams extracted from the plasma to be reduced from the periphery to the central longitudinal axis of the multi-aperture matching channel with radial compression of the ion beams. The factors listed above provide the possibility of matching in size and position in space of the parameters of ion beams with the apertures of the drift tubes of the accelerating RF system.

Analysis of distinctive essential features and properties resulting from the proposed technical solutions, namely, the possibility of selecting ions into the beam from a large area of the plasma surface for each individual channel, spatial matching of the trajectories and geometric dimensions of the beams in these channels with the corresponding parameters of the apertures of the drift tubes of the accelerating RF system, showed that the new properties that have appeared contribute to an increase in the current of the ion beam at the exit of the accelerator and the achievement of the set technical result and make it possible to consider the claimed technical solution as corresponding to the criterion of the utility model.

The multi-aperture matching channel with radial compression of ion beams is effective for use in multichannel ion accelerators, into which charged particles are injected from a plasma with a low ionic component density and a large ion emission surface area. The originality of the proposed technical solution lies in the fact that the dimensions of the input apertures of the drift tubes of individual channels of the utility model exceed the geometric dimensions of the apertures at its outlet, which makes it possible to select ions for acceleration along each separate channel of the multichannel accelerating RF system from the plasma surface, the area of which exceeds the corresponding channel size accelerating RF system. The presence of several such channels in this injector contributes to an increase in the total surface area of ion extraction from the plasma into the acceleration mode. The applied method of electrostatic focusing of ions by an electric field in the accelerating gaps between adjacent drift tubes, which have the same aperture sizes in these gaps, which decrease synchronously towards the output of the utility model, provides effective radial compression of the ion beam. Radial compression, in conjunction with the general directionality of the electric field in individual channels, allows the extraction of ions from a large area of the plasma surface and provides a decrease in the loss of charged particles during their transportation and when they are introduced into the channels of the accelerating HF system. The factors listed above contribute to an increase in the current of ion beams accelerated in a multichannel accelerator.

Brief description of the drawings.

In fig. 1 shows a diagram of a diagram explaining the device of a multi-aperture matching channel with radial compression of ion beams and its operation, where:

1 - case,

2 - shells,

3 - drift tubes,

4 - lines of force of the electric field in the gaps between the drift tubes,

5 - final apertures of the drift tubes at the exit of the matching channel with radial compression of ion beams,

6 - input apertures of the drift tubes of the accelerating HF system,

BP - power supply unit.

In fig. 2 shows a general view of a multi-aperture matching channel with radial compression of ion beams, where:

2 - shells (similar to Fig. 1),

3 - drift tubes (similar to Fig. 1),

7 - racks,

8 - flanges.

In fig. 3 shows a view from the side of the accelerating RF system of a multi-aperture matching channel with radial compression of ion beams, where:

5 - final apertures of the drift tubes at the exit of the matching channel with radial compression of ion beams (similar to Fig. 1),

7 - stands (similar to Fig. 2).

In fig. 4 shows a view from the side of the ion source of a multi-aperture matching channel with radial compression of ion beams, where:

3 - drift tubes (similar to Fig. 1),

7 - stands (similar to Fig. 2).

An example of implementation.

In fig. 1 shows in a schematic form a structure that explains the process of matching the apertures in this utility model with the input apertures of the drift tubes 6 of the accelerating RF system of the multi-aperture ion accelerator and its operation.

According to fig. 1, individual channels in this utility model have a common angular directivity in space, converging to the central longitudinal axis of the entire device, from the AI to the drift tubes of the accelerating HF system. Such their trajectory and the proposed design of these channels make it possible to match the output apertures of the 5 end drift tubes 3 in size and spatial position with the apertures of the 6 drift tubes installed at the input of the accelerating HF system. The dimensions of the apertures of the drift tubes of 3 separate channels at the inlet of the multi-aperture matching channel with radial compression of ion beams exceed the dimensions of the apertures of the drift tubes of the same 3 separate channels installed at the outlet of this utility model, which makes it possible to efficiently use a large part of the plasma surface of the IR for the extraction and acceleration of ions. in the accelerator, regardless of the size of this surface.

As shown in fig. 1, a multi-aperture matching channel with radial compression of ion beams consists of a housing 1 made in the form of two end flanges with apertures for separate channels and separated in space by 6 posts electrically isolated from these flanges. These flanges 8 and posts 7 are shown in Fig. 2, fig. 3, fig. 4. Shells 2 with apertures of separate accelerating channels are attached to these posts through electrical insulators, fig. 1. Moreover, the diameters of the apertures are reduced towards the outlet flange of the housing 1 in such a way as to match the dimensions of the apertures 6 of the drift tubes installed at the input of the accelerating RF system. Shells 2 are electrically connected to power supply units (PSUs) in such a way that an electric potential difference arises between them, the value of which provides electrostatic focusing of the ion beam, sufficient for its passage through drift tubes 3 along the length of the entire individual channel, Fig. 1. A conical drift tube 3 is installed in the apertures of the shells 2 of such a design, in which the sizes of the inlet and outlet holes of each drift tube 3 coincide with the size of the outlet of the previous drift tube and the size of the inlet of the subsequent drift tube, respectively, Fig. 1. This provides focusing and radially symmetric compression of the ion beam by the "sagging" focusing electric field 4 when the beam is accelerated in the gap between the drift tubes 3.

A multi-aperture matching channel with radial compression of ion beams operates as follows. The ions extracted from the ionizing plasma into the drift tube 3 of a separate channel by the electric field of the first shell 2 and accelerated by this field, passing through the first drift tube 3 along the beam, fall into the gap between the exit of this drift tube and the entrance of the drift tube 3, installed in the aperture of the next shells 2, Fig. 1. Electric field 4 in this gap acts on the ion beam similarly to an immersion electrostatic lens (the principle of which is described in the work of SI Molokovsky, AD Sushkov. Intensive electron and ion beams. M. EnergoAtomizdat 1991. pp. 89-99 ), focusing the ions to the central longitudinal axis of the channel by the "sagging" lines of force of the electric field 4, Fig. 1. Electrostatic focusing of an ion beam by a static electric field (the principle of which is set forth in the work of SI Molokovsky, AD Sushkov. Intense electron and ion beams. M. EnergoAtomizdat 1991. pp. 26-31) arises as a result of a special configuration, namely, symmetric sagging to the central axis of the gap, the lines of force of the electric field 4 in the area between the drift tubes 3, Fig. 1. The essence of the effect of this focusing is that the ions emerging from the first drift tube are acted upon by an electric field with a force F, of different directivity in the first and second halves of this gap, Fig. 1. The horizontal component of this force accelerates the ions throughout the gap. The vertical component of the force F, in the first half of the gap, displaces the ions towards its central axis, Fig. 1, causing a focusing effect. In the second half of this gap, the vertical component of the force F deflects the ions in the opposite direction, Fig. 1, defocusing the ion beam, since the ions in the first half of the gap have a lower velocity than in the second, and spend more time on its passage than the time they pass through the second half of the gap, which they pass with a higher velocity, since they constantly experience acceleration throughout the gap between the drift tubes from the action of the horizontal component of the force F, Fig. 1. As a result of the combined action of the above factors, the ion beam focusing effect appears in the gap between adjacent drift tubes. The difference in electrical potentials in the gaps between the drift tubes 3 is set to such a value that the ion beam, passing through the corresponding drift tube, falls into the next gap without losses. This algorithm of ion movement is repeated in all gaps along a single channel and operates in all separate channels of this utility model. The general direction of the electric fields in the gaps between the drift tubes of 3 separate channels, Fig. 1, allows deflecting ion beams from the periphery, reducing them to the central longitudinal axis of a multi-aperture matching channel with radial compression of ion beams. The configuration of the lines of force of the electric field in the gaps between the drift tubes 3, Fig. 1, creating a focusing effect, promotes radial compression (squeezing) of the ion beam in these gaps during the flight of ions through the channel.

The applied technical solution, with the same size and decreasing in magnitude from the input of the multi-aperture matching channel with radial compression of ion beams to its output, the output and corresponding input apertures of adjacent drift tubes 3 in combination with a varying magnitude of the electric potential difference on the shells 2, in the apertures of which these drift tubes are installed 3, Fig. 1, creates factors that make it possible to increase the rigidity of ion focusing in the gaps between the drift tubes as the beam passes through a separate channel, increasing the possibility of its compression. This promotes an increase in the ion density in the beam and an increase in the current in the channel. The dimensions of the outlet apertures 5 in the drift tubes of 3 separate channels installed at the outlet of the multi-aperture matching channel with radial compression of ion beams are matched in magnitude and position in space with the corresponding channels 6 of the drift tubes of the accelerating RF system of the accelerator, Fig. 1.

Implemented in the proposed application, the possibility of spatially spaced regions of ion extraction from plasma with simultaneous radial compression of ion beams in separate channels allows in multi-beam ion accelerators, with a low density of the ion component in the plasma, to increase the total current of the ion beam accelerated by the accelerator.

The multi-aperture matching channel with radial compression of ion beams is distinguished by its simplicity of design, reliable operation, and low cost of manufacture.

Claims (1)

A multi-aperture matching channel with radial compression of ion beams, consisting of a body, shells with coaxially located apertures converging to its central longitudinal axis, characterized in that the diameter of these apertures decreases as they converge, and hollow drift tubes, made so that the inlet diameter of each drift tube is greater than its outlet diameter, which in turn is equal to the inlet diameter of each subsequent drift tube, and the housing and shells are electrically isolated from each other and electrically connected to separate power supplies.

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