DE69430582T2 - DEVICE FOR GENERATING AN IMAGE OF AN OBJECT USING A CURRENT OF NEUTRAL OR CHARGED PARTICLES, AND A LENS FOR CONVERTING THE CURRENT OF NEUTRAL OR CHARGED PARTICLES - Google Patents

Description

Field of technology

The present invention relates to devices for imaging an object during its examination by means of irradiation processes or for forming patterns according to the structure of an object with a given configuration, and to devices for controlling the flow of neutral or charged particles, i.e. for bending the beams of such particles, for focusing said beams, for converting a diverging radiation into a quasi-parallel radiation and vice versa, for filtering and monochromatizing said radiation, splitting particles with different energies, etc., both during the process of forming the image of an object and in solving other problems such as arise in medicine, nuclear physics, etc.

Background of the state of the art

According to the state of the art, methods are known for examining various objects, which involve producing an image of their structure by subjecting the objects to the action of a stream of neutral or charged particles (neutrons, electrons, gamma quanta, X-rays, etc.) and recording the radiation distribution intensity resulting from the interaction with the object. The image produced in this way is considered to be the distribution of the interaction properties between the object and the radiation used, said properties being an inherent part of the various components, in particular as a two-dimensional projection of a spatial distribution attenuation of the radiation resulting from its transmission through the object (see the textbook "Production automation and industrial electronics", Moscow, Sovetskaya entsiklopediya PH, 1954, volume 3, page 277; volume 1, page 209 (in Russian).

It is also known that similar methods are used in electronics, X-ray and other lithography to create a predetermined pattern according to a known structure of a specially manufactured object (i.e. stencil, mask); see, for example, "Electronics: An encyclopedic dictionary", Moscow, Sovetskaya entsiklopediya PH, 1991, pp. 254-255 (in Russian).

The methods discussed above are carried out using apparatus comprising a radiation source, means for arranging an object capable of being exposed to the radiation, and means for recording images responsive to radiation resulting from the interaction between the radiation emerging from the source and the object.

However, the capabilities of said methods are very limited, unless means are used to control a primary particle stream or a stream resulting from interaction with the object, in particular to control the spectrum, direction, width, divergence and other beam parameters.

Some previously known radiation methods for producing an image of an object are known to use the concept described above and are carried out by means of devices which, in addition to the devices mentioned, also have optical elements capable of solving some of the problems mentioned above, in particular the control of the beam width and the selection of particles deviating from a given direction (see "Physics of image visualisation in medicine", edited by S. Webb, Russian translation published in Moscow Mir PH, 1991, pp. 41, 101, 134). Leaving aside the fact that the problems solved in this way are of a special nature, it should also be noted that the concepts used in the methods mentioned are associated with the use of a radiation source with excess intensity.

The use of other types of optics in devices of the type described here is the subject of the symposium "X-ray optics and microscopy", edited by G. Schmahl and Dr. Rudolph, Moscow, Mir PH. 1987, which particularly considers the use of Fresnel zone plates for beam focusing (p. 87) and mirror optics for grazing incidence (p. 174). However, due to the special features of the applied physical concept, Fresnel zone plates are characterized by extremely high selectivity with respect to particle energy (wavelength), which is why the said plates cannot be used to control broad-spectrum radiation. As further noted in the said publication, the said plates should be very small and the devices using the said plates should have a small angular aperture and a low aperture ratio. As for the said mirror optics, despite practically acceptable geometric dimensions, this optics is usually capable of only a single reflection, which is due to extremely low values of the angle of the total external reflection effective for radiations of the discussed ranges. Consequently, devices using such optics have only limited possibilities for controlling the radiation beams and an extremely small angular opening, which corresponds to low angular sizes of the total external reflection.

Another prior art device for producing an image of an object (US Patent No. 5,175,755, published December 29, 1991) is of a more sophisticated design. The device uses an optical system consisting of a group of passages having reflecting walls and adapted for radiation transmission, acting as a lens, to control a radiation beam. Various methods are provided for controlling the particle stream in a device having such an optical system, the said methods being described in said US patent, in particular converting a diverging radiation into a quasi-parallel radiation before the object is exposed to said radiation, transmitting a broad spectrum radiation in conjunction with a possibility of cutting off the hard radiation component and converting the size of the resulting image.

US Patent No. 5,192,869, published on March 9, 1993, describes the construction of a lens for converting the flow of neutral or charged particles, which is of a more sophisticated type than the above-mentioned device for controlling the flow of particles and which is suitable for use as a component part of a device for forming the image of an object. The lens in question uses rigid support members spaced apart along the length so as to provide rigid mounting of the passage-forming members at locations where they are passed through the holes in the support members. A suitably selected arrangement of said holes makes it possible to achieve the correspondence of the axial lines of the individual passages with the forming surfaces of a required shape. In order to meet these conditions of radiation transmission along the passages without significant loss, the cross-sectional dimensions of each individual passage must be as small as possible. However, the above-mentioned structure, which involves the use of a mechanical assembly process, imposes limits on a minimum cross-sectional dimension of the passage. In particular, radiation passages designed as glass capillaries or polycapillaries with a diameter of the order of 300 microns lose the properties required for proper assembly. The capillaries or polycapillaries therefore begin to "float" in the air; they cannot be given the necessary radius curvature during assembly and the capillaries sag slightly between the support point. Such a limitation of their diameter means that the radiation cannot be focused on a point with a diameter smaller than the capillary internal diameter or the polycapillary external diameter. The minimum focal diameter that can be achieved with such lenses is 0.5 mm, which means that a high radiation concentration is impossible due to a focal diameter that is too large.

A limited size of the passages results in a limitation of the range of the energies used. For a given focal length f, even if the radiation source is point-shaped, a Minimum radiation angle of incidence on the capillary edge zone θ = d/2f, where d is the passage diameter.

For efficient radiation transmission, it is desirable that the value θ approaches or even be smaller than the limiting angle of reflection θc, since the limiting angle decreases as the energy increases. This condition limits the use of high energies in first and second generation lenses. For example, at an X-ray energy E = 10 keW, the radiation capture in the passage is not higher than 15%, and with an increase in focal length, the capture angle decreases and, consequently, the efficiency of the system. From all of the above, it follows that it is necessary to switch to radiation passages with cross-sectional dimensions down to micron and submicron, which is not possible with the designs described above for the reasons mentioned above and which entails the use of mechanical assembly during manufacture. Mechanical assembly is the cause of another disadvantage. The angular divergence is determined by Δθ = ΔL/L, where ΔL represents the sum of variations in the capillary diameter and the hole diameter in the support disk. L is the distance between the disks, which should not exceed 1-3 cm. Since ΔL represents about 10% of the mentioned diameters and the value of the latter is in the order of 500 microns, Δθ is in the order of 5·10-3 rad., which proves unacceptable for many applications.

The device and lens described above, as taught by U.S. Patents Nos. 5,175,755 and 5,192,869, respectively, are most relevant to the device and lens proposed herein. In addition to the factors already mentioned, their capabilities are also limited by the fact that only the transit properties of the individual, independently functioning passages are used. In this case, the wave properties of the particles passed through the passage are only exhibited when said particles are reflected from the passage walls during their transmission along said passages, which is due to the fact that no measures are taken in the lens design to reduce the effect of the interaction between the particles after they have passed through different passages. This limits the achievable degree of radiation concentration to the geometric accuracy of aligning the passages towards a desired point and further precludes energy separation of the particles, should this be necessary, and monochromatisation of the radiation by means of the lens itself without the aid of other means. The above-mentioned limitations adversely affect the capabilities of the device for forming an image of an object which has an optical system in the form of a lens consisting of a group of passages with reflecting walls for the purpose of transmitting radiation; in particular, the said limitations preclude any increase in the image resolution of the device, the reduction of the radiation load to which the object under investigation is exposed and the use of a low-power radiation source.

Disclosure of the invention

As far as a device for producing an image of an object is concerned, the present invention aims at increasing the effectiveness of using radiation in the form of a stream of neutral or charged particles to produce an image, which appears as a distribution of the intensity of the radiation after its interaction with the object. The technical result achieved is a higher resolution together with a reduced radiation effect that arises on the object, accompanied by an increased radiation intensity that affects the sensor elements (sensors) of an image-producing device. The above-mentioned factors acting together promote a wider range of examination media and those that serve as carriers of the resulting image.

As regards a lens for converting a stream of neutral or charged particles, the present invention aims to increase the achievable degree of radiation concentration, including concentration of radiation having different wavelengths of an input current in different spatial zones. The structure of the lens proposed in the present invention overcomes the adverse effect of technological limitations inherent in the known lens adopted as a prototype.

Furthermore, the device for forming an image of an object as appears from claim 1 and the lens as appears from claim 27 provide some further technical advantages in a number of particular cases of their implementation and application, which form the subject of a detailed description hereinafter.

The device proposed here for producing an image of an object, like the known device described in US Patent No. 5,175,755, comprises a radiation source in the form of a stream of neutral or charged particles, a device for arranging an object which can be exposed to the radiation effect produced by said source, a device for producing an image which makes it possible to record the distribution of the intensity of the radiation after it has interacted with the object, and an optical system which includes at least one lens for converting a stream of particles and which is located between the radiation source and the device for arranging the object or between said device and the image producing device, said lens being formed by a group of passages with reflecting walls for transmitting radiation. In contrast to the previously known devices, the device proposed here has all or part of the passages that form the lens for converting the particle stream and are arranged in an orderly manner over the lens cross-section while maintaining axial symmetry.

In the present case, the condition of mirror symmetry with respect to one or two mutually perpendicular axes of the lens cross-section can be met for all passages arranged in an orderly manner across the lens cross-section. An orderly arrangement of the passages that maintain a centric or rotational symmetry with respect to the lens longitudinal axis is also possible.

The precise observance of symmetry enables a coherent interaction between equal, radiation source and, after passing through the lens, their progression along different paths at the same spatial convergence point and the onset of interference phenomena which ultimately lead to the technical result mentioned above.

A particle stream converting lens (or any such lens forming part of the optical system when multiple lenses are used) can be formed by densely stacked miniature lenses whose total cross-section is variable in the longitudinal direction of the lens according to their required longitudinal profile. Such structural arrangement of the lens makes it possible to dispense with the need to use support elements as a means of forming the lens longitudinal profile and of determining the shape of the lens passages, and limitations associated with the mechanical structure which entail the use of such support elements can be avoided.

Increased efficiency in radiation focusing, which is the most important goal of the above-described design of a lens (of lenses) forming part of the proposed device for imaging an object, promotes both higher resolution and radiation intensity in the region of positioning of the imaging device, high enough to record the image, and further contributes to a lower intensity of radiation to which the object is exposed.

Such a device for forming an image of an object is most effective when it uses a lens(es) in which the passages, evenly spaced across the lens cross-section while maintaining axial symmetry, are grouped into similar modules, evenly spaced while maintaining axial symmetry. Each of said modules (called first-stage modules) may in turn be formed of second-stage modules having the same shape and mutual arrangement and the same number as the first-stage modules. Accordingly, the second-stage modules may be formed of smaller third-stage modules, etc. Each of the highest-stage modules may in fact be a miniature lens.

According to one of the groups of special embodiments of the proposed device, the image generating device is arranged such that the radiation guided through the object can be forwarded to it.

In such a case, the optical system comprises a number of asymmetric lenses, each of which is capable of reducing the image produced, said asymmetric lenses being arranged between the means for arranging an object and the means for forming an image in such a way that each of said asymmetric lenses passes the radiation from the object elements closest to the lens entrance, and all of the asymmetric lenses make it possible to form a mosaic image of the object. As a result of such an embodiment of the device, the radiation dose to which the object is exposed is reduced in direct proportion to the degree of image size reduction and of focusing of the radiation emerging from the asymmetric lenses.

According to another particular embodiment of the group mentioned, an optical system comprises an image-magnifying diverging half-lens mounted between the device for arranging the object and the image-forming device, said half-lens consisting of conical capillaries or polycapillaries. The radiation source can be located at the focal point of said diverging half-lens or on its optical axis in a defocused position. In the latter case, energy filtering of the particles captured is provided. If the same purpose is intended when a radiation source of fixed size with a circular exit opening is used, its central part can be shielded.

The optical system in the embodiments considered here, characterized by the attachment of a conically diverging half-lens for image magnification, can further comprise a second diverging half-lens consisting of conical capillaries or polycapillaries and having smaller cross-sectional dimensions compared to the first, said half-lens being located between the radiation source and the device for arranging the object This feature enables the formation of an image with sufficient dimensions and the reduction of the object irradiation dose.

In the special cases described above, the object is exposed to directly diverging radiation generated by the source. According to another special embodiment, the optical system has a lens or half-lens for generating a quasi-parallel particle beam, which is located between the radiation source and the device for arranging the object.

A source of divergent radiation may have the ability to form two characteristic Kα spectral lines. In this case, the optical system also has a rotatable filter window located either in front of or behind the lens or hemi-lens with the intention of forming a quasi-parallel beam. The filter window has two alternating sectors, each of which is arranged to suppress the radiation of one of the two Kα spectral lines. The above-mentioned lens or hemi-lens has a longitudinal axis with a curvature to cut off the hard radiation components or a straight longitudinal axis, in which case a set of parallel capillaries is arranged to the object in front of the device to cut off the hard radiation components. In such a case, two images are temporarily formed which correspond to the results of the interaction between the object and the particles with the energy corresponding to the said Kα; spectral lines, thus creating the conditions for the final image formation by subtracting one of the two images from the other, thus making it possible to improve the degree of reproduction of the said image by suppressing the disturbing background.

In a further special case, also characterized by the use of a diverging radiation source with the possibility of forming two characteristic Kα spectral lines, the optical system has two lenses or half lenses arranged at an angle to one another for generating quasi-parallel beams, and two crystal monochromators, each of which differentiates between the two Kα spectral lines, wherein the said crystal monochromators are located behind the said lenses or half lenses. half lenses with the ability to reflect the monochromated rays towards the means for locating the object. The device further comprises a second means for forming images, each of the image forming means being located behind the means for locating the object with the ability to receive the radiation reflected by one of the crystal monochromators after it has passed through the object. The device thus presented also has the ability to form two images corresponding to different Kα spectral lines.

In another particular embodiment of the device, the optical system comprises a lens arranged between the radiation source and the device for positioning the object, said lens being able to focus the radiation within the object to produce the image of its component on which the focusing takes place. In this case, the radiation source, said lens and the device for producing the image are rotatable together with respect to the device for positioning the object without affecting their mutual position and that of the radiation focal point, the latter forming the centre of said rotational movement. Such a structural arrangement makes it possible to concentrate the radiation on the same part of the object during the entire observation time, without irradiating the same parts surrounding the part under observation during said observation time. Due to said feature, said parts are exposed to the radiation alternately, i.e. only for part of the observation time and at a lower radiation concentration than the part under observation.

According to another group of particular embodiments of the proposed device, the image generating device is positioned such that secondary radiation scattered or excited in the matter of the object can be transmitted to the said device as a result of interaction of said matter with the radiation generated by the source.

In one of the above-mentioned special embodiments, the radiation source is capable of generating a stream of electrons or ions to Exciting secondary X-ray radiation in the substance of the object and the optical system comprises a hemi-lens which is arranged to transmit said secondary radiation to the image generating device and is capable of scanning the object with its focal point.

In a further particular embodiment of the group mentioned, the optical system comprises a lens for transmitting the radiation generated by the source to the object and a lens for transmitting the secondary radiation to the image generating device, both of the lenses mentioned having a common focal point and being jointly movable for the purpose of scanning the object with their common focal point.

In both of the above-mentioned special embodiments, a beam monochromatization device, in particular as a double-curved crystal, can be arranged between the lens for transmitting the secondary radiation to the image-generating device and the said device.

A polarizing baffle may be arranged between the lens for directing the radiation to the means for locating the object and said means, the baffle being able to change the direction of the beam reflected therefrom by 90º with respect to the beam incidence. The polarizing baffle may be a crystal monochromator.

According to a particular embodiment of the device, in which confocal lenses are provided, one of which transmits the radiation to the device for arranging the object and the other transmits the secondary radiation from there, the latter can have radiation passages symmetrical with respect to the optical axis and a focal point located in the space between the lens exit and the image generating device, a micro-aperture being provided in said space, which makes it possible to scan the image of the object.

With such a structural arrangement, the device can be used for an elemental analysis of a sample serving as an object.

The device can thus be adjusted to a specific energy value of the secondary radiation particles by positioning the micro-aperture on the optical lens axis, said lens transmitting the secondary radiation with a shift from the focal point according to the energy E of the particles by the following value:

where

f is the focal length in accordance with the energy E and ΔE is the required resolution value with respect to the energy E .

In order to eliminate a background generated by secondary radiation with non-interesting energies, those zones of the lens cross-section over which the particles possessing such energies predominantly spread can be closed at the lens exit with a radiation-tight circular shield (if it is the central part of the lens) or an annular shield (if the lens layers are away from their axis).

In another particular embodiment, which provides for image generation by means of Compton radiation scattered by the object, the optical system comprises a lens arranged between the radiation source and the device for arranging the object, which lens is arranged to form a quasi-parallel beam. In this case, a collimator, which appears as a system of straight capillaries, is arranged between the device for arranging the object and the image generation device. The radiation source, the lens, the collimator and the image generation device are located in the same half-space in relation to the device for arranging the object.

In yet another embodiment, in which the image of an object is generated by means of Compton scattered by internal object elements Radiation is generated, the optical system comprises a lens arranged between the radiation source and the device for arranging the object and arranged to focus the radiation within the object, and a collimator in the form of a system of conical capillaries, said collimator focusing on the same point as the lens. The collimator is arranged between the device for arranging the object and the image forming device, while the lens, the collimator and the image forming device are arranged in the same half-space in relation to the device for arranging the object and are jointly movable in relation to it without affecting their mutual arrangement, whereby the object can be scanned with a common lens and collimator focal point.

In both of the above-mentioned special embodiments, the fact that all parts of the device are arranged in the same half-space in relation to the device for arranging the object makes it possible to examine an object that is only accessible from one side.

Yet another particular embodiment of the device utilizes both the radiation transmitted through the object and the radiation scattered by its internal components. With this objective in mind, the device comprises a source of plane-polarized radiation and the optical system comprises a lens constructed of square mono- or polycapillaries having similarly oriented walls and located between the radiation source and the device for locating the object, said lens being capable of focusing the radiation within the object. Furthermore, the optical system comprises a further lens constructed of conical capillaries, said lens being located in front of the image forming device and having a common focal point with said lens for focusing plane-polarized radiation. An optical axis of the lens constructed of conical capillaries is at right angles to the optical axis of the lens for plane-polarized beam combination in the plane of the vector of intensity of the magnetic field of said radiation. It is possible to use an additional imaging device and a lens consisting of conical capillaries, both arranged symmetrically to those mentioned above on the other side of the device for arranging the object. The device, according to the particular embodiment considered, also comprises a lens for generating a quasi-parallel beam, said lens being located on an extension of the optical axis of the lens for plane-polarized beam combination and confocally thereto, said additional imaging device being located behind said lens for generating quasi-parallel radiation. In this case, the radiation source, all the above-mentioned lenses and both imaging devices are jointly movable relative to the device for arranging the object without affecting the mutual arrangement of said components, thereby enabling scanning of the object, similarly to the previous embodiment. The use of both scattered radiation and radiation transmitted through the object contributes to the amount of information obtained about the object under investigation and, all other things being equal, enables the radiation dose to the object to be reduced.

The lens proposed here for converting a stream of neutral or charged particles, which is a component of the previously described optical system of the device in each individual embodiment thereof, is formed, like the known lens described in American Patent No. 5,192,869, by an aggregate of radiation passages with reflecting walls. In contrast to the said known lens, all or parts of the said passages of the proposed lens are evenly arranged while maintaining axial symmetry across the lens. In particular, the types of symmetries listed above in the summary of the invention are possible, which relate to the device for imaging an object.

In a special case, all the passages of the lens can have straight longitudinal axes, which can be either parallel or convergent (divergent). In the latter case, the passages are conical. Interference phenomena that occur due to the uniform and symmetrical arrangement of the passages across the lens cross-section make it possible to focus the radiation emerging from the lens itself onto parallel passages from which the lens is formed.

In the special lens designs in which the passages forming the lens are curved (except for the central passage), their curvature is the same for the passages equidistant from the lens's longitudinal axis or plane(s) of symmetry. This makes it possible to satisfy the condition of a uniform and symmetrical arrangement of the passages over any lens cross-section and to focus the emerging radiation using not only the conducting properties of the passages forming the lens, but also the interference phenomena occurring in the space in which the radiation emerging from the lens propagates (on the basis of reciprocity, the lens has similar properties when it acts "as a receiver", i.e. with respect to the diverging radiation emerging from the quasi-point source and incident at its output, the lens can serve as a device for generating a quasi-parallel beam). The cross-section of the passages is variable in their longitudinal direction in accordance with a change in the longitudinal cross-section as a whole, whereby the passages can be stacked closely together, thus eliminating the need for support elements when assembling the lens.

If the lens passages are curved, the lens can be conical or funnel-shaped, semi-drum-shaped, symmetrical or asymmetrical drum-shaped, etc.

If the outer surface of the lens is convex (in particular, semi-drum-shaped, drum-shaped, etc.) with the aim of creating the most favourable conditions for the interference of the outgoing radiation (from the point of view of its efficient focusing), the passages can be conveniently arranged in layers around the longitudinal axis of the lens, while having the same total cross-sectional areas of the passages belonging to said layers, the radii of the curved passages (ie all except the central passage) decreasing from the longitudinal axis of the lens towards the lens circumference. The most suitable is an inversely proportional relationship between the radius of curvature and the number of layers, counting from the central layer located on the longitudinal axis of the lens.

The best results are achieved when one of the following quantitative relationships is maintained:

a) The radii of curvature of all curved passages must not

Rc = 2d/θ²c

not exceed,

where

d is the passage diameter; and

θc represents the critical reflection angle for the particles with the lowest energy in the spectrum of the transmitted radiation;

b) the radii of curvature of all curved passages have a minimum value of

Rc = 2d/²c

where

d is the passage diameter; and

θc represents the critical reflection angle for the particles with the highest energy in the spectrum of the transmitted radiation;

(c) the radii of curvature of all curved passages satisfy condition "a" and are inversely proportional to the number of layers to which they belong (when the number of layers is counted from the lens's long axis towards its circumference).

The curvature of the lens can also be variable in the longitudinal direction of the lens, in particular monotonically variable.

The passages may have a spiral surface that helps to control polarized radiation. It is useful for a lens with such passages if all of its passages have the same spiral direction or if the passages of different groups have opposite spiral directions.

The lens assembly step can be facilitated and its accuracy improved if the lens consists of similar modules evenly arranged over the lens cross-section with precise axial symmetry (in particular, symmetry with respect to mutually square cross-sectional axes). In this case, said modules (first-stage modules) can consist of smaller modules (second-stage modules), which in turn can be formed of even smaller modules (third-stage modules), and so on. Each individual module of a given height is formed from modules of lower height in a number equal to the number of first-stage modules, with the same shape and mutual arrangement as the first-stage modules.

In all embodiments of the above-mentioned lens, its passages are formed in particular by inner walls made of glass mono- or polycapillaries.

In all particular embodiments of the lens, the inner walls of their passages can be provided with coatings consisting of at least one layer and forming together with the walls themselves a multilayer structure in which their adjacent layers have different electromagnetic properties. Furthermore, the contact surface between at least two adjacent media can be in a different phase state compared to their base layer. In the conduction of particles, this enables the use not only of the phenomenon of multiple reflection, but also diffuse and potential scattering, which contributes to increasing the radiation capture angle and improves the conduction of charged particles (if the coating electrically conductive and superconductive) and that of neutral particles (if the coating appears as a magnetic layer), etc.

Single or multi-period diffraction structures can be applied to the inner walls of the passages, making it possible to use the lens to monochromatize the radiation entering its entrance, to split said radiation into streams corresponding to the different spectral lines (if the coatings are applied as multi-period diffraction structures), etc.

A lens design is also possible in which a single reflection is used in each of the lens passages to convert a diverging radiation into a quasi-parallel radiation or to focus this radiation. In this case, the abutting ends of the passages are located on two concentric spherical surfaces. The axes of the passages are radial and their longitudinal and cross-sectional dimensions are chosen to provide a single reflection that allows radiation capture within the limits of four times the critical angle of reflection when the radiation source is located on the optical lens axis and is spaced from the inner spherical surface so that its distance corresponds to half its radius.

According to the various embodiments, the lens may be a miniature lens group, in particular densely layered and with a total cross-section that is variable in the lens longitudinal direction according to its longitudinal profile. In particular, in the above-mentioned lens embodiment consisting of modules of the first, second and higher levels, each module of the highest level may be a miniature lens. In this case, a variety of miniature lenses may be provided, e.g. those belonging to the various layers surrounding the longitudinal axis with different radiation capture angles and different focal lengths.

With the exception of the uniform arrangement across the lens cross-section, the lens can also have unevenly arranged passages, whereby these passages can outnumber the evenly arranged ones.

Short description of the drawings

The present invention is illustrated below with reference to the accompanying drawings, in which:

Fig. 1 the generation of the image of an object irradiated by a quasi-parallel particle beam using a reducing half-lens;

Fig. 2 the generation of the image of an object irradiated by a diverging particle beam using a reducing asymmetric lens;

Fig. 3 the generation of a magnified image of the internal object component using the radiation passed through the object;

Fig. 4 the generation of a mosaic image of an object using a source of diverging radiation and a system of reducing asymmetric lenses;

Fig. 5 the generation of a magnified image of an object using a diverging radiation source and a conical hemi-lens;

Fig. 6 the formation of the image of an object using a diverging radiation source, a conical lens for radiation filtering and a magnifying conical half-lens;

Fig. 7 and 8 special cases of generating alternating images of an object in accordance with the two Kα spectral lines, where the mentioned cases differ in their methods or cut off the hard spectral part;

Fig. 9 the simultaneous generation of images of an object corresponding to the two Kα; spectral lines.

Fig. 10 the formation of the image of an internal part of an object, on which the radiation emanating from the source is focused, without the same tissues surrounding said part being subjected to a permanent radiation effect;

Fig. 11 the generation of the image of an object using the radiation scattered by the object;

Fig. 12 the formation of the image of an object, whereby the image-transmitting lens focuses on one of the object components and irradiates it with a particle stream that excites X-rays;

Fig. 13 is a view of Fig. 12 with monochromatization of a secondary radiation;

Fig. 14 the use of a conical half-lens, which focuses to transmit the secondary radiation to one of the object components, and an asymmetrically cut, double-curved crystal monochromator;

Fig. 15 the generation of the image of an object using backscattered Compton radiation;

Fig. 16 is a view of Fig. 15 with the radiation emerging from the source focused on the inner object component;

Fig. 17 the simultaneous formation of images of an object using radiation that has been passed through and scattered by the object, the object being subjected to the action of plane-polarized radiation;

Fig. 18 a uniform arrangement of passages across the lens cross-section with a mirror symmetry with respect to two axes as well as a centric and a rotational symmetry;

Fig. 19 a symmetrical lens consisting of planar arrangements in cross section;

Fig. 20 a lens structure in cross section that only has rotational symmetry;

Fig. 21 the use of a group of parallel, straight capillaries as a lens and the distribution of the intensity of the emerging radiation in the focal plane;

Fig. 22 shows a symmetrical lens arrangement in cross section, wherein said lens consists of rectangular shaped modules and a module of said arrangement is formed from smaller modules of the second stage;

Fig. 23 is a view of a lens in the form of a curved capillary bundle;

Fig. 24 a view of a polycapillary with a cross-section that does not change in length;

Fig. 25 is a view of a lens in the form of a miniature lens aggregate;

Fig. 26 is a view of a conical lens formed using miniature lenses;

Fig. 27 is a view of a lens (half-lens) designed as a half-drum and designed to convert diverging radiation into quasi-parallel radiation (or to focus quasi-parallel radiation);

Fig. 28 is a view of a drum-shaped lens for focusing diverging radiation;

Fig. 29 and 30 asymmetric lenses for focusing a diverging radiation, wherein said lenses have a constant or a variable radius of curvature of the passages in the longitudinal direction of the lens;

Fig. 31 is a view of a funnel-shaped lens with a concave side surface;

Fig. 32 is a view of a lens with coaxial passages or layers of passages with a symmetry in relation to the lens longitudinal axis; and

Fig. 33 a lens for converting a diverging radiation into a quasi-parallel radiation (or for focusing a quasi-parallel radiation), said lens being designed as an aggregate of radially laid out passages and being capable of individually reflecting the converted radiation.

Most suitable method for carrying out the invention

As stated above in the description of the present invention, which relates to an apparatus for forming an image of an object, said apparatus is capable of forming a direct shadow image in of the radiation passed through the object and an image in the form of a distribution of the radiation intensity scattered by the object or excited in the substance.

Considering the function of the proposed device in detail, as long as correct intelligibility is not affected, the term "object" is used for the sake of brevity instead of the term "device for arranging the object" (since in describing the function of the device it is essentially an interaction between the radiation and the object itself rather than an interaction with the device for its arrangement, although it is the said device and not the object which turns out to be the unit of the device).

An embodiment of the device according to the previous of the above-mentioned cases is shown in Fig. 1, wherein an object 2 is irradiated by a quasi-parallel particle stream (means for generating said stream, e.g. a synchrotron, have been omitted from the drawing). The radiation passed through the object 2 is transmitted to an image forming device 4 by means of an image-reducing half-lens 3. As stated above, this enables the irradiation dose of the object to be reduced without reducing the radiation intensity, which is possible due to the radiation concentration that occurs when the image size is reduced by the half-lens 3. As device 4, any radiation receiver (detector) can be used that is able to visualize the acquired image (e.g. a film reel loaded with film, an X-ray image intensifier, etc.; see in particular "Physics of image visualization in medicine", edited by S. Webb, Moscow Mir PH, 1991, Volume 1 (Russian translation).

If the condition is met

?1 ? (d1 /d2 )?2

where

θ1 represents the divergence of a quasi-parallel beam;

θ2 represents the divergence of the radiation emerging from the half lens 3; and

do, d1 represent the entrance and exit diameters of the half lens 3 the minimum loss of transmitted radiation is achieved. This allows the current of the irradiation source to be reduced and the object irradiation dose to be reduced.

If the object 2 is exposed to radiation emerging from a source 1 of finite dimensions and a diverging radiation (Fig. 2) is generated which, after being passed through the object 2, is transmitted to the image forming device 4 by means of the asymmetric lens 3 which, as in the previous case, reduces the image size, the following condition must be met:

b/f = (d1 /do)?2 ,

where

b represents the diameter of the exit aperture of the radiation source 1 ;

f represents the distance between the radiation source 1 and the object 2 ;

do, d1 represent the entrance and exit diameters of the asymmetric lens 3; and

θ2 represents the divergence of the radiation emerging from the asymmetric lens 3 and incident on the image forming device 4.

To produce an enlarged image of an internal component 6 of the object 2 (Fig. 3), the radiation emerging from the source 1 is focused on said component 6 by means of a lens 5. The distance of the image generating device 4 from the object 2 in this case depends on the desired degree of image magnification.

Information about the object can be obtained in divergent rays (Fig. 4); in this case, behind the object 2 there is a system of converging lenses 3, while behind said system there is the image forming device 4 in the form of a mosaic pattern formed by the half-lens system 3, while the radiation source 1 is located at the focal point of said system. In this case, the Relation (2) applies to each of the half lenses 3. Such an embodiment of the device is used in particular in mammography.

According to one of the embodiments, the image of the object 2 is transmitted with the help of a diverging lens 7 at the focal point at which the radiation source 1 (Fig. 5) is located. In the embodiment mentioned, the components of the lens 7 are made up of conical passages that widen conically in the direction of the image generating device 4. The spatial resolution of such an optical system approaches the diameter of the transmission passage at the lens entrance.

The radiation may be subjected to filtering before the object, using a further conical lens 7' located in front of the object 2 and a secondary scattered radiation arising in the object 2 is suppressed by means of the lens 7 (Fig. 6), which is an improved version of a medical grid.

A number of embodiments of the proposed device, primarily intended for use in angiography, are shown in Figs. 7 to 9.

In an embodiment according to Fig. 7, the radiation source emits photons with two Kα spectral lines (in angiography, these lines lie above and below the iodine absorption line, i.e. in the vicinity of 33 keV). A rotating window is filled with a filter which absorbs one of the above-mentioned lines at one moment and lets the other line through, and reverses its effect at the next moment. The window mentioned can also be arranged behind the lens. A lens 10 makes the beam quasi-parallel and at the same time, due to a curvature present in it, cuts off the hard radiation component emitted from the X-ray tube.

Fig. 8 shows an embodiment of the device in which a set 11 of parallel capillaries is used to cut off the hard radiation component, which is located behind a half-lens 9 forming a quasi-parallel beam.

In a further embodiment (Fig. 9), the image is formed by means of two half lenses 9, 9', two crystal monochromators 12, 12' and two In this case, one of the Kα spectral lines is transmitted and reproduced by means of the crystal monochromator 12 and the image forming device 4 and the other Kα spectral line is transmitted and reproduced by means of the crystal monochromator 12' and the image forming device 4'.

Protective shields 13, 13' are provided so that the radiation emerging from the source 1 does not directly hit the object 2.

The half lenses 9, 9' form quasi-parallel beams, while the crystal monochromators 12, 12' provide monochromatized radiation corresponding to one of the Kα spectral lines mentioned. In all three embodiments described above (Figs. 7 to 9), a further lens can be provided in front of each image generating device, said lens being intended to reduce the image size and also serving to reduce the radiation dose for the patient. In order to achieve an effective reduction in the radiation dose, the beam divergence θ1 in front of the patient must satisfy the condition:

θ1 = θc(d1/do)², where θc is the critical reflection angle with energy E = 33 keV and the factor (d1/do)² is the ratio between the output and input cross-sectional areas of the lens.

The two resulting X-ray images (which alternate at regular intervals in the device according to Figs. 7, 8 or are present simultaneously in the device according to Fig. 9) are processed together using the subtraction method with the resulting suppressed background image, in which the object components that are of interest to the operating personnel, for example blood vessels, are more easily recognizable.

According to one of the variants of a practical application of the proposed device, wherein an image is formed by means of radiation passed through the object, the radiation is focused using the lens 5 on the inner component 6 of the object 2, which is the target of the examination, e.g. a tumor (Fig. 10). The image forming device 4 is located opposite the object 2 on the optical axis of the lens 5. The radiation source 1, the lens 5 and the image forming device 4 are arranged stationary in relation to each other, however, a system which they jointly form is provided for the center, which is in reality the point 6 of radiation focusing. The radiation source 1 and the image generating device 4 are movable over the spherical surfaces of the corresponding radii (such a surface 14 for the radiation source 1 is shown in dashed lines in Fig. 10). Due to such a movement, the radiation is constantly concentrated, for example, on the tumor 6 whose image is to be generated, while the tissues surrounding the tumor are exposed to the radiation only for a certain period of time during the observation process.

Fig. 11 shows an embodiment of the device in the case where secondary radiation is used for image formation, which is scattered by the object or excited therein by the radiation emerging from the source. In the drawing of the said figure, the lens 5 focuses the radiation emerging from the source 1 onto one of the components of the object 2, and a lens 15 focused on the same components from the input side transmits the secondary radiation to the image forming device 4. Due to the movement of a system consisting of the radiation source 1 and the lenses 5, 15 in relation to the object 2 (the mutual arrangement of the said components remains unaffected) or due to the displacement of the object in relation to the said system, scanning of the object with a common focus of the lenses 5 and 15 becomes possible, whereby by means of the image forming device 4 one can generate a distribution pattern of the object properties that affect the parameters of the secondary radiation. Such a design helps to both solve the problem of locality and suppress the background resulting from the scattered radiation, which contributes to the sensitivity of the method. This particular embodiment of the proposed device is suitably used for precision location of the location or position of defects, for locating heavy components, etc.

Figures 12 to 14 show an embodiment of the proposed device for use in image formation of an object with the aid of the radiation excited therein.

Secondary X-rays can be excited using an electron or ion beam 16 in the object 2 (in the area of which a sample of the material or substance to be examined can be located), whereby said radiation can be collected at the image generating device 4 with the aid of a half lens 17 (Fig. 12).

According to a further embodiment of the device (Fig. 13), the radiation collected by the half lens 17 is directed to a monochromator 12 and further to the image generating device 4.

The radiation can be efficiently monochromatized by using a conical half lens 18 and a double-curved crystal monochromator 19 (Fig. 14).

Two further specific embodiments of the proposed invention provide for image formation using Compton backscatter radiation.

According to a previous embodiment (Fig. 15), a quasi-parallel beam formed by the half-lens 9 (or obtained directly from a synchrotron source) is directed onto the object 2. A backscattered radiation is directed onto the image generating device 4 via a collimator 20 consisting of a system of straight capillaries.

According to the latter embodiment (Fig. 16), the radiation generated by the source 1 is focused via the lens 5 onto the object 2, in particular onto its inner component 6. A lens 21 consisting of conical capillaries focuses on the same point, with the image forming device 4 arranged behind the lens 21. Depending on the situation, the object can be scanned by a beam (in which case a system consisting of the radiation source 1, the lens 5, the lens 21 and the image forming device is movable relative to the object as an integral unit), or conversely, the object is movable relative to the aforementioned components of the device.

In both cases, all components of the device are located in the same half-space in relation to the object. The device for arranging the object can be an aid that facilitates contact with the object, e.g. a probe that can be moved together with the other components of the device in relation to the object.

To analyze a variety of objects, including medical diagnoses, one can effectively use polarized radiation. Plane-polarized, quasi-parallel radiation, for example from a synchrotron source, is focused on the inner component 6 of the object 2 by means of a lens 22 constructed of square mono- or polycapillaries, the walls of which are all aligned in the same way (Fig. 17). Another lens 24 works in pairs with the lens 22, while the image generating device 4' is located behind the lens 24.

A further image forming device 4 is located behind the conical lens 23, the optical axis of which is perpendicular to a common optical axis of the lenses 23 and 24 and which is parallel to the vector of a magnetic field generated by the plane-polarized radiation. The conical lens 23 is focused on the same inner point of the object as the lenses 22 and 24. According to such an embodiment, two images are generated in the device, one of which is formed by the device 4' using the radiation transmitted through the object and the other by the device 4 using the scattered radiation. Another pair of similar components can be arranged symmetrically in relation to the lens 23 and the image forming device 4, which makes the device more informative.

It should be emphasized that the possibility of scanning with the lens focus inside the object opens up fundamentally new possibilities in the diagnosis of various objects, including medical diagnosis. It is in fact the beginning of a new type of microscopy, in which the focus of a source is, so to speak, inside the object. Furthermore, the geometric image blur of the source is significantly reduced. Such image blur is usually expressed by the following conventional formula:

Ur = bds/If,

where

b is the size of the object, If is the distance between the object and the tube focus and ds is the distance between the object and the detector.

If the source is outside the object, the values of ds and If are comparable and the value of Ur approaches that of b, i.e. the resolution approaches the source size. If the lens focus is in close proximity to the defect in the object, the value of ds can be very low; consequently, the resolution increases. In this case, a fundamentally new possibility arises, i.e. a large increase in the spatial dimensions of the defect to be examined.

As stated above, axially symmetric lenses have interference properties, i.e. the mentioned lenses have a centric maximum, as well as secondary maxima and minima. The width of the centric maxima approaches the diameter of the radiation passage, e.g. the capillary diameter. A total intensity in the centric maximum is directly proportional to N²c, where Nc represents the number of capillaries in the lens. Thus, such lenses can be used effectively to obtain information about the object having defects.

For example, if the defect Nq overshadows capillaries, the intensity in the centric maximum becomes almost proportional (Nc-Nq)². This quadratic relationship makes it possible to very effectively observe even small defects, even small defects in relation to the object. For example, by scanning different zones in the object and then subtracting the intensity values from each other in the centric maxima (the so-called subtraction method), one can easily determine the presence of the defect and its location.

High energy resolution can be achieved by using a device in which the device for arranging the object (sample) is followed by a lens with axial symmetry. Such a lens is capable of very high energy resolution. For example, if it is required to achieve energy resolution on the optical lens axis up to a certain degree ΔE in the range of a certain energy E, a spatial resolution Δf = fΔE/E corresponds to the energy resolution mentioned, where f is the lens focal length for the energy E.

In an embodiment of the device adapted for use in science and in analytical instruments and devices, X-rays are used to obtain information about the elemental composition of the sample. In fluorescence analysis, a primary X-ray beam excites characteristics and the elemental composition of the sample is reproduced by analyzing said lines. Usually, two methods are used in this case, namely fine dispersion analysis against wavelengths, since Bragg diffraction is used, or energy dispersion analysis, in which the energy spectrum of secondary particles is measured.

In both cases, the use of the lenses of the proposed device offers obvious advantages. For example, when performing diffraction measurements using X-rays generated by an X-ray tube as output rays, a loss of radiation intensity of the order of 6-7 occurs. This is due to the fact that only those photons that satisfy the Bragg condition are used, i.e. the photons should have a divergence of 10-3 to 10-4 rad, depending on the type of crystal used.

Tomographs have found widespread use in modern diagnosis, despite having a number of inherent disadvantages, namely high radiation dose and the fact that their spatial resolution is always far less than adequate, both of which are related. If, for example, one tries to double the resolution, the radiation dose must be increased by 16 times. For this reason, a resolution value of one to several millimeters is common in current tomographs.

It is routine practice to use a continuous spectrum of bremsstrahlung, which is associated with the onset of the so-called "hardening effect", whereby harder photons are absorbed in the object to a lesser extent than softer ones, which is why some Difficulties were encountered in image reconstruction, especially in the bone-muscle interface.

The above-mentioned difficulties can be overcome by using the device proposed here. In this case, the tomograph design can be the same in the second generation of tomographs, i.e. the radiation source is located in front of the patient, while an image-reducing lens and a detector are arranged behind it (i.e. the sensor of the image generating device). The patient is immobilized while the radiation source, the lens and the detector are rigidly connected to one another and scan the patient's body.

To get rid of the "hardness effect", the radiation emerging from the source can be monochromatized using various methods. For example, a half-lens can be arranged behind the radiation source and a group of parallel capillaries can be located behind the half-lens, while the angle of incidence of the radiation emerging from the half-lens to the said group can be adjusted, thus adjusting the radiation spectrum.

In modern tomographs, the distribution density is estimated by recording the radiation from the source to the radiation detector. In this case, in order to obtain information about the distribution density in one or another section, a large number of irradiations of the section (usually more than a hundred) must be carried out at different angles, with the irradiation dose usually being 1R or more. The situation can be improved by recording the Compton scattering at the point of the object under investigation simultaneously with the recording of the radiation absorption.

For this purpose, the focal point of the X-ray beam is directed at the area to be examined. Another lens system (or collimator system) rigidly connected to the aforementioned X-ray lens is directed at the same focal point. Such a system is able to scan the object in three directions. The second lens system mentioned above is connected to detectors that are able to record Compton scattering. Another detector system is located to record the radiation absorption behind the object opposite the first lens. Such a tomography system is intended to provide better resolution at a lower radiation dose. The arrangement of the device which carries out the said method is similar to the arrangement shown in Fig. 17.

The practical application of the proposed device in medical diagnosis can lead to a drastically reduced radiation dose and a high spatial resolution. A reduction in the radiation dose can be achieved due to filtering of quasi-parallel radiation and due to the possibility of image transmission with a reduction in the size of the object under examination.

X-ray screens, intensifying screens, vidicons, etc. have an image formation threshold that varies depending on the screen type, photon energy, etc. Here and in the following, the threshold mentioned is taken as n = 10⁸ photons/cm² for estimation purposes.

The object is irradiated by a parallel beam of photons. Behind the object there is a lens (or a series of lenses) adapted to focus the radiation; behind the said lens or series of lenses there is a screen. In the proposed device the ratio of the input diameter to the output diameter can be 100:1.

For efficient focusing, the output beam divergence δθ in this case must be δθ/θc = d₁/do, i.e. do/d₁ = 100. It is clear that δθ/θc should be of the order of 10⁻²; where E = 20 keV, θc = 2·10⁻³, i.e. with dimensions reduced by a factor of 100, δθ = 2·10⁻⁵ rad. In this case, the output area of a single capillary is 10⁴ times reduced. With such focusing, an amount as small as half the amount of photons that reached the blunt exit end of the lens behind the object falls on the screen.

In this particular case, the number of photons required for the image formation threshold is reduced by a factor of 1/2·10⊃min; ⊃4;. This means that in the case where a lens is placed behind the object, the number of photons incident on the object can be reduced by a factor of 5000. At the same time, a good spatial resolution is required. Since the resolution is two or three times the capillary entrance diameter, for a 100 micron resolution the capillary diameter should be of the order of 30 microns. In this case, with dimensions reduced by a factor of 100, the capillary exit diameter should be of the order of 0.3 microns. The convergence angle (or conical angle) of the capillaries is of the order of 2 10-5 rad. and the lens length is about 75 cm, assuming that the lens is made up of several capillaries or polycapillaries. There are two constraints on the minimum size of a capillary, one of which is related to diffraction and is independent of the photon energy, the limiting size being C/ωp = 100 Å and where C is the speed of light and ωp is the plasma frequency (Langmuir). The limit mentioned is small and can be ignored in this particular case. The other limitation is the physical imaging process. The photon energy is converted on the screen of the imaging device, ie in the detector, into electron energy, which when dissipated forms light quanta that create the image of an object.

Maximum resolution in this case is related to the width of the electron beam, which corresponds to about 10 microns.

Let S₁ designate a minimum area of the capillaries at the exit end in front of the screen, said area depending on the final electron beam width; S₁ = (10 µm)² = 10⁻⁶ cm². If the entrance area of the capillaries is So, the reduction in the irradiation dose J is J = aSo/S₁, where a represents the loss of radiation when it is passed through a converging capillary, said loss being equal to ¹/₂ and So = 10⁻², J = 5000.

A minimum resolution of 1 corresponds to the capillary entrance diameter multiplied by a factor of the order of 3, i.e. 1 = 0.3 mm in this specific case.

Consequently, as So increases, J also increases, but 1 decreases inversely proportional to the increase in So.

In cases where small images are to be produced, J decreases because it is necessary to use capillaries with small entrance diameters.

For example, if it is required to obtain the resolution of an image of a tumor of approximately 1 mm in size, capillaries with a diameter of approximately 0.3 mm must be used, where J = 500. Similarly, for a 0.3 mm tumor, J = 50.

A particular design feature which is part of at least one of the lenses of the optical system used in the proposed device (and, whenever the optical system has a single lens, is present as an inherent feature of said single lens) is the fact, as stated above in the description of the present inventions, that radiation passages are evenly arranged across the cross-section of said lens while maintaining axial symmetry. Such a feature is inherent in the design of the lens proposed here, even when said lens is used alone or as a component of other devices in which streams of neutral or charged particles are to be converted.

Fig. 18 shows a uniform arrangement of lens passages, in which there is a mirror symmetry with respect to the cross-sectional axes X and Y. In this special case, a centric symmetry also occurs with respect to the lens longitudinal axis, which runs perpendicular to the drawing plane through the intersection point of the X and Y axes: each component to be examined corresponds to the same component that lies on a straight line and runs through the named component and the named point is on the other side of the named point (center of symmetry) at the same distance from it as the component under consideration.

Apart from the above, Fig. 18 shows a rotational symmetry with respect to the same axis as the centric symmetry, i.e. when rotated 180º around said axis, the figure shown in the drawing coincides with itself.

Fig. 19 shows the presence of a mirror symmetry in a structure having passages with cross-sectionally open surfaces of their walls and formed by curved flat arrangements 25.

Fig. 20 shows an ordered arrangement of square passages across the lens cross-section while maintaining rotational symmetry: when rotating around the lens longitudinal axis, which passes through point 0 at right angles to the drawing plane, the figure depicted in the drawing coincides with itself.

As indicated in the above description of the invention, the uniform arrangement of the passages provided in the lens over the lens cross-section, while maintaining axial symmetry, creates the conditions for the onset of interference phenomena for the particles emerging from the lens. This makes it possible to focus the radiation efficiently, even in the simplest design of the lens, i.e. in the form of a group 26 (Fig. 21) made up of straight parallel mono- or polycapillaries (the so-called "capillary bar"). The presence of coatings applied to the walls of the radiation passages is indicated in dashed lines in Fig. 21 and is described in a series of figures below, with the role played by them being considered separately. Depending on the length of the group 26, a single, double or multiple reflection can occur in each of the passages 27. The result is an interference pattern occurring in a focal plane 28 which is exactly as far from the lens exit end as the radiation source 1 is from the lens entrance end, said interference pattern corresponding to a graphical representation 29 (Fig. 21) of radiation intensity I in relation to the X coordinate, said graphical representation showing the width of the main maximum which corresponds approximately to the diameter of a single passage.

The size of the focal point is of the same order of magnitude in other lens designs with passages evenly arranged over the lens cross-section while maintaining axial symmetry. For comparison purposes, it is worth noting that in the absence of interference phenomena, the size of the focal point is of the following order of magnitude:

If d + 2θcf,

where

d is the cross-sectional dimension of a single passage;

f is the focal length; and

θc represents the critical external reflection angle.

To give an example, with the particle energy E = 8 keV, the angle θc has a magnitude of 3·10⊃min;³ rad. For a typical value of f = 10 cm, the following expression applies: If = d + 0.6 mm, i.e. the degree of focusing better than 0.6 mm is unattainable, even if the passages are made of very fine capillaries. By providing interference conditions in the proposed lens, it is possible to overcome the above limitation, with the result that the degree of focusing depends solely on the passage diameter.

The interference-generated performance of the proposed lens is combined with technological advantages inherent in the lens structure, in which orderly arranged radiation passages are in reality an aggregate of similar modules 30 arranged uniformly while maintaining axial symmetry (Fig. 22, 20).

The above modules can in turn consist of smaller modules that are second-level modules relative to the previous ones, which are in fact first-level modules, and so on.

Fig. 22 shows smaller modules 31 from which each of the modules 30 is constructed, in particular a module aa'b'b.

Depending on the number of stages of the modules used in the lens construction, the symmetry of the first, second, etc. order is determined. The modules of the next stage, which form the module of the previous stage, have the same number, shape and mutual arrangement as the modules of the first stage for each module of the previous stage. The modules of the highest stage are formed directly by the radiation passages.

The use of a lens in the form of curved capillaries 27 (Fig. 23) is very promising. In this case, it is convenient to use a polycapillary, i.e. a miniature optical system (Fig. 24). In such a case, the lens is actually a group of miniature optical systems, which allows its effect to be increased several times.

An important trend in the optics proposed here may be an optical system appearing as an aggregate or as a group of miniature lenses, half lenses, etc. Such groups of miniature half lenses 33 and lenses are shown in Figs. 25 and 26.

A miniature lens is usually a drum-shaped polycapillary with a diameter that is usually no larger than 0.1-1 mm. The polycapillary is filled with several thousand or several tens of thousands of hollow passages, the cross-section of which is variable in the longitudinal direction of the passages so that all passages can be aligned to the same point.

The miniature lenses are arranged in a single group of hundreds or thousands of passages without using any support elements to form and maintain the longitudinal profile of an optical system. In cases where support elements are used, they perform their function with respect to the miniature lenses rather than the individual passage capillaries. In this case, the effect of such an optical system is increased many times over in comparison with the case where the optical system consists only of capillaries or polycapillaries.

A set of miniature lenses creates many new possibilities, e.g. one can form a lens with two, three or more focal lengths, for which purpose the set can be divided into two, three or more layers, each layer consisting of miniature lenses whose focal lengths are different.

Miniature lenses with passages of micron and submicron sizes are manufactured using intricately designed geometric figures according to the drawing technique in a furnace having an appropriate configuration and a specified temperature range.

An optical system shown in Fig. 26 and designed as a beam of conical lenses, also having the miniature lenses 33, makes it possible to focus a quasi-parallel radiation efficiently. Furthermore, such a structure is able to suppress the hard part of the radiation spectrum. This is the fact that that as the radiation passes along the passages, the angle of reflection for both the photons and the neutrons increases in relation to the passage walls. Since harder radiation has a smaller angle of reflection, the high-energy photons and neutrons are the first to be eliminated from the multiple reflection mode.

If the lens consists of modules 30 (Figs. 20 and 22) or of smaller modules 31 (Fig. 22), such modules may in fact be the miniature lenses described above.

Fig. 27 shows a half-drum-shaped half-lens for converting a diverging radiation emerging from the source 1 into a quasi-parallel radiation. An input end 34 of said half-lens is concave in order to provide a uniform intensity of the emerging beam within its cross-section.

Figs. 28-30 show a drum-shaped symmetrical lens and a drum-shaped asymmetrical lens, both arranged to focus a diverging radiation emerging from the source 1. When the symmetrical lens according to Fig. 28 is used, the radiation focuses at a distance f from the output end which corresponds to a distance between the radiation source 1 and the lens input end. For the lenses according to Figs. 29 and 30, the above distances differ from each other in that they correspond to f₂ and f₁ respectively. In the lens according to Fig. 29, its passages have the same radius of curvature over their entire length, while in the lens according to Fig. 30 the right-hand part of the radiation passages is curved by a radius R₂ which is longer than a radius R₁ by which the left-hand part of the passages is curved. There can be asymmetrical lenses in longitudinal section, in which the passages have a variable radius of curvature that changes monotonically. A lens with curved passages can also be conical or funnel-shaped (Fig. 31); in this case, the lens side surface is concave instead of convex, in contrast to the lenses according to Figs. 27-30. Such a lens can be used to produce a magnified image of an object located in front of the lens entrance (if a quasi point source of radiation is used). The precision of the resulting image corresponds approximately to the cross-sectional dimension of the passage at the lens entrance.

Apart from the fact that the proposed lens may have passages arranged in an orderly manner over its cross-section in the sense discussed above, each "layer" of passages usually has its own radius of curvature and consequently its own length. Here and in the following, passage layers are understood to mean in particular groups of passages forming closed contours which are rectangular with a rectangular cross-section of the lens shown in Fig. 22 or annular with a circular cross-section; a layer may be formed by a single passage, e.g. corresponding to the configuration in Fig. 32. Such layers are coaxial and surround the lens longitudinal axis, being spaced from said axis at different distances. It is also possible for the layers not to form closed contours, e.g. to be "flat", which is the case when the lens (Fig. 19) has a rectangular cross-section, said layers having the same width as said cross-section. For each of these layers arranged on one side of the plane of symmetry of the lens, said plane extending through the lens longitudinal axis, there should be a similarly symmetrically arranged layer on the other side of said plane. In a cross-sectional view of the lens, the passages forming such layers are symmetrical with respect to the axis of said cross-section. For this reason, monochromatic photons are subjected to an unequal number of reflections in different passages, so that a phase-different wave system is formed after said photons have emerged from the lens, considering the process from the standpoint of wave theory. A phase difference arises due to different path lengths of the photons through the passages in their longitudinal direction. If the passages are unevenly arranged, no useful effects are produced, but in the case of axial symmetry, as mentioned above, wave interference results. Of practical importance is the fact that a considerable proportion of the The energy emerging from the lens is concentrated in the central maximum and the size of the central interference point itself approximately corresponds to the cross-sectional dimension of a radiation passage.

In some cases, straight mono- or polycapillaries, or otherwise a group of them, can be used efficiently to focus the radiation emerging from the quasi-point source, the radiation capture angle being 2θc and the number of reflections being equal to "1". One of these cases, in which a system of source-aligned mono- or polycapillaries is used, is shown in Fig. 33. In this case, the abutting ends of the capillaries are located on two spherical surfaces 34, 35 with a respective radius R, Rx and a common center 36. The radiation source 1 is located on the axis of the optical axis at a distance corresponding to R/2 from the inner spherical surface and the dimensions of the optical system and the capillary length are chosen so that the capture angle is equal to 4θc and the radiation is subjected to only a single reflection. The same lens can be used to focus a quasi-parallel beam.

Capillary lenses and half lenses can be designed to function in many respects as Fresnel zone plates. To do this, it is necessary that all layers have approximately the same surface area, which can be achieved in two ways.

One of them is as follows. With a given energy value, the radiation capture is determined by the factor γ = Rθc²/2d; where R < Rc = 2d/θ², so that γ < 1, i.e. the factor of capillary filling with radiation is less than 1. The surface area of the n-th layer of capillaries, which is located at a distance rn from the center, is obviously Sn = 2πrΔrn, where Δrn represents the capillary diameter in the n-th layer (or the width of the n-th layer). However, Δrn is directly proportional to γ, which in turn is proportional to Rn. If we now choose Rn ~ 1/n (i.e. the radii of curvature decrease in the direction away from the center), then It is clear that Sn is directly proportional to rn1/n, but since rn is directly proportional to n, Sn is independent of n, ie all layers have the same area, but the layer width decreases from the center towards the outline. Such a geometry is completely similar to the geometry of a Fresnel zone plate.

The other type consists in that from the beginning each capillary layer has its own diameter in order to fulfill the condition of constant areas of all layers.

In both cases described above, the lens functions similarly to a Fresnel zone plate.

When making capillary lenses and hemi-lenses, the capillary can be drawn in such a way that it is twisted and the photon paths resemble a spiral line. It is possible that part of the capillary "twist" in one direction and the other part of it in the other. This gives rise to a number of interesting possibilities. Firstly, if a beam of non-polarized photons (or neutrons or charged particles) is applied to the lens entrance, the said beam can be subdivided into a series of plane-polarized beams due to the rotation effect. Secondly, if a plane-polarized beam is provided from the beginning, the plane of polarization of the said beam rotates in a twisted capillary.

Some further possibilities open up as a result of applying coatings to the walls of the radiation passages to create diffuse and possible scattering or interference of the transmitted radiation, which occurs in multilayer structures formed by the mentioned coatings and the passage walls (the presence of such coatings is shown schematically in dashed lines in Fig. 21, 25, 26 and 31).

To cut off the soft part of the spectrum in order to obtain a quasi-monochromatic spectrum from a complex spectrum, the passage walls can be coated with a material which effectively absorbs said spectral part.

The fact that the coatings are multilayered allows not only the transmission of radiation, but also the selective selection of a part of it. Due to the resulting interference, the critical angle of reflection and the reflection factor are significantly increased, causing the above-mentioned phenomenon to occur in the passages.

The presence of a small transition layer can, in many cases, increase the lens efficiency significantly. For example, if neutrons are transmitted, the layer in question can be ferromagnetic, which increases the angle of reflection. If charged particles are transmitted, the layer can be crystalline, which causes reflection to occur in a way that behaves like the transmission of particles in crystals.

Coating the dielectric substrate with a metal layer enables the "flow through" of charged particles through such a medium. In the opposite case, the dielectric substrate is charged in order to prevent the "flow through" of particles through its charge.

In this case, the substrate and the reflection surface differ in their properties, since the latter is a metal layer.

When simultaneous multiple reflection of radiation on alternating media differing in physical properties and scattering is used, a possibility for effective control of said radiation arises, while the lenses using said combination can be widely used in different fields of engineering. In particular, a set of rectangular or square capillaries can be used, coated with a multilayered structure in such a way that the period of said structure alternates, whereby after reflection two different quasi-monochromatic beams are formed, which are similarly space-oriented.

Alternating media can be in different phase states. For charged particles, crystalline structures are used as a reflection medium, e.g. a layer with a thickness of several dozen Ångström units. In this case, the reflection from the layer in question takes place in a similar way to the passage between the atomic levels of a crystal.

The critical angle of reflection of neutrons in a layer in which a magnetic field is present is determined according to the following formula:

?c = ?[Nb/? ± (m/2πr²²)uB]1/2

where

N is the nuclear density;

λ represents the neutron wavelength;

b is the nuclear coherent scattering range;

u is the neutron magnetic moment;

m represents the neutron mass;

B represents the magnetic induction; and

which represents Planck’s constant.

The presence of two signs, plus and minus, and consequently two angles, represents two possible polarizations of neutron spin.

For strong magnetic fields where Nb < (m/2π²)uB, a single critical angle of reflection is observed. In this case, totally reflected neutrons are polarized.

For example, if you form two- or three-dimensional structures with a magnetic reflection surface, you can control not only the path of the neutrons, but also their polarization.

Alternating media can be used where the reflecting medium is actually a magnetic mirror, e.g. a thin cobalt mirror. By using alternating media with different magnetic properties, critical reflection angles can be increased without decreasing the reflection factor.

Commercial applicability

The invention proposed here can be used in the manufacture of analytical instruments, in particular in elemental analysis, three-dimensional local analysis, defectoscopy, ecological monitoring, for the manufacture of tomographs with micron and submicron resolution, in microscopy for the development of high-performance and high-intensity microscopes, in particular for the microscopic examination of biological objects, in microelectronics for contact and projection lithography, in X-ray and diffractometry for the development of novel collimators as novel diffraction and interference devices, in particular for improving radiation density.

As far as medicine is concerned, the present invention can find application in the early diagnosis of oncological, cardiovascular and some other diseases, in the development of novel endoscopes and dental devices, in the treatment of inoperable diseases, including carcinomas, as well as in neurosurgery, medical radiology, etc.

Claims (59)

1. Device for generating an image of an object with a radiation source (1), the radiation occurring as a stream of neutral or charged particles, a device (2) for arranging the object with the possibility of being exposed to the radiation effect produced by the said source (1), a device (4) for generating images, said device (4) being able to record the distribution of the intensity of the radiation after its interaction with the object and an optical system comprising at least one lens for converting a particle stream and located between the radiation source (1) and the device (2) for arranging the object or between said device (2) and the image generating device (4), said lens being formed by a group of passages having reflecting walls for transmitting radiation by means of multiple total external reflection, characterized in that said lens is formed by densely stacked miniature lenses, each miniature lens consisting of several of said radiation passages, the diameters of which are variable in the longitudinal direction of the miniature lens and which define a common single focal point, the total cross-section of each miniature lens is variable in the longitudinal direction of said lens and the central axis of each miniature lens is curved and all or part of the radiation passages are arranged axially symmetrically over the cross-section of said lens. 2. Device according to claim 1, characterized in that the passages arranged in an orderly manner over the lens cross-section are grouped in a number of similar modules (30) which are arranged uniformly while maintaining the axial symmetry. 3. Device according to claim 2, characterized in that the lens comprises, in addition to said modules (30), the modules of the first stage also comprises modules (31) of higher levels, each module of the previous levels being formed by modules of a next level having the same shape, mutual arrangement and the same number as the modules of the first level. 4. Device according to claim 2 or 3, characterized in that each of the modules of the highest level is a miniature lens. 5. Device according to one of claims 1 to 3, characterized in that the image generating device (4) is in such a position that the radiation guided through the object can be forwarded to said device. 6. Device according to claim 5, characterized in that the optical system has an aggregate of asymmetric lenses (3) which are arranged between the device (2) for arranging the object and the image generating device (4), said lenses being composed in such a way that they transmit the radiation emerging from different components of the object. 7. Device according to claim 5, characterized in that the optical system comprises a diverging half lens (7) which is constructed from conical capillaries or polycapillaries and is located between the device (2) for arranging the object and the image generating device (4) in order to magnify the image of the object. 8. Device according to claim 7, characterized in that the radiation source (1) is located at the focal point of the diverging half-lens (7) consisting of conical capillaries or polycapillaries. 9. Device according to claim 7, characterized in that the radiation source (1) is located on the optical axis of the diverging half-lens (7) consisting of conical capillaries or polycapillaries in a position outside the focal point. 10. Device according to claim 7, characterized in that the radiation source (1) has a circular exit opening, the central part being shielded and arranged on the optical axis of the diverging half-lens consisting of conical capillaries or polycapillaries in the focal plane of said half-lens. 11. Device according to claim 7, characterized in that the optical system further comprises a second diverging half-lens (7') consisting of conical capillaries or polycapillaries, said second diverging lens having smaller cross-sectional dimensions compared to the first lens (7) and being located between the radiation source (1) and the device (2) for arranging the object. 12. Device according to claim 5, characterized in that the optical system comprises a lens or half-lens for generating a quasi-parallel beam of particles, said lens or half-lens being located between the radiation source and the device for arranging the object. 13. Device according to claim 12, characterized in that the radiation source (1) is capable of generating two characteristic Kα spectral lines and that the optical system also comprises a rotatable filter window (8) having two alternating sectors, each of which is adapted to suppress the radiation of one of the two Kα spectral lines, said filter window being located either in front of or behind the lens or half-lens adapted to form a quasi-parallel beam, said lens or half-lens having either a longitudinal axis with a curvature to cut off the hard radiation components or a straight longitudinal axis, in which case a set of parallel capillaries (11) for arranging the object is arranged in front of the device (2) to cut off the hard radiation components. 14. Device according to claim 12, characterized in that the radiation source (1) is able to generate two characteristic Kα spectral lines and the optical system further comprises a second lens or half-lens (9') adapted to form a quasi-parallel beam, non-parallel to the first beam, and two crystal monochromators (12, 12'), each arranged to be located between the two Kα spectral lines. distinguish spectral lines, wherein said crystal monochromators are located behind said lens or hemi-lens to reflect the monochromatized rays towards the device (2) for arranging the object, the device further comprising a shield (13, 13') to prevent the radiation generated by the source (1) from being directly incident on the device (2) for arranging the object, and a second image generating device (4'), each of the image generating devices (4, 4') being located behind the device (2) for arranging the object to record the distribution of the intensity of the radiation moving through the object and reflected by one of the crystal monochromators (12, 12'). 15. Device according to claim 5, characterized in that the optical system comprises a lens (5) located between the radiation source (1) and the device (2) for arranging the object, said lens being able to focus the radiation within the object, said lens, the radiation source (1) and the image generating device (4) being rotatable together with respect to the device (2) for arranging the object without influencing their mutual arrangement and the position of a radiation point (6) which forms the focal point as the center of said rotary movement. 16. Device according to one of claims 1 to 3, characterized in that the image generating device is designed in such a way that secondary radiation scattered or excited in the material of the object can be transmitted to the said device as a result of interaction of said material with the radiation generated by the source. 17. Device according to claim 16, characterized in that the radiation source is capable of generating a current (16) of electrons or ions for exciting a secondary X-ray radiation in the substance of the object (2) and that the optical system comprises a half-lens (17) which is arranged to transmit said secondary radiation to the image generating device (4) and is capable of scanning the object (2) with the focal point of said half-lens. 18. Device according to claim 16, characterized in that the optical system has a lens (5) for transmitting the radiation generated by the source (1) to the device (2) for arranging the object and a lens (15) for transmitting the secondary radiation to the image generating device (4), both of said lenses having a common focal point and being jointly movable for the purpose of scanning the object with their common focal point. 19. Device according to claim 17 or 18, characterized in that a beam monochromatization device (12) is arranged between the lens (15, 17) for transmitting the secondary radiation to the image generating device (4) and said device (4). 20. Device according to claim 18, characterized in that between the lens for transmitting the radiation generated by the source to the device for arranging the object and said device, a polarizing baffle is applied, said baffle being able to change the direction of the beam reflected therefrom by 90º with respect to the beam incidence. 21. Device according to claim 20, characterized in that the polarization baffle is a crystal monochromator. 22. Device according to claim 17 or 18, characterized in that the lens for transmitting the secondary radiation has radiation passages which have a centric symmetry with respect to its optical axis and capable of focusing the radiation transmitted into the space between the lens exit and the image forming device, a microdiaphragm being provided in said space with a possibility of scanning said image. 23. Device according to claim 22, characterized in that the microdiaphragm is arranged so that its opening lies on the optical axis of said lens and is spaced apart by a distance specified below is shifted from the focal point, which corresponds to a given energy of the passed particles, where E represents the given energy of the particles being transmitted; f is the focal length of said lens in accordance with said energy; and ΔE represents the required level of energy resolution. 24. Device according to claim 16, characterized in that the optical system comprises a lens (9) located between the radiation source (1) and the device (2) for arranging the object and capable of forming a quasi-parallel beam, and a collimator (20) acting as a system of straight capillaries and located between the device (2) for arranging the object and the image generating device (4), the radiation source (1), the lens (9), the collimator (20) and the image generating device (4) being arranged in the same half-space with respect to the device (2) for arranging the object. 25. Device according to claim 16, characterized in that the optical system comprises the lens (5) located between the radiation source (1) and the device (2) for arranging the object and is arranged to focus the radiation within the object and a collimator (21) which appears as a system of conical capillaries, wherein said collimator is focused on the same point as the lens (5) and is located between the device (2) for arranging the object and the image generating device (4), wherein the lens (5), the collimator (21) and the image generating device (4) are arranged in the same half-space in relation to the device (2) for arranging the object and are jointly movable in relation to the device (2) without affecting their mutual arrangement. 26. Device according to claim 16, characterized in that the radiation source (1) is capable of generating a quasi-parallel, plane-polarized radiation and the optical system comprises a lens (22) arranged to focus said plane-polarized radiation and made up of square mono- or polycapillaries, said lens being located between the radiation source (1) and the device (2) for arranging the object and being arranged to focus the radiation within the object and a lens (23) consisting of conical capillaries and located in front of the image generating device (4), said lens (23) having a common focal point with the lens (22) for forming a plane-polarized radiation and an optical axis located in the plane of the vector of the intensity of the magnetic field of said radiation and arranged at a right angle to the optical axis of the lens (22) for combining the rays of said plane-polarized radiation, and a lens (24) which is located on an extension of the optical axis of the lens (22) and which has a common focal point with it, said lens (24) being designed to generate quasi-parallel radiation, the additional image generating device (4') being placed past the lens (24) while the radiation source (1), all of the above-mentioned lenses and the two image generating devices are jointly movable with respect to the device (2) for arranging the object, so that their mutual arrangement is not influenced. 27. Lens for converting the flow of neutral or charged particles formed by an aggregate of passages which have reflective walls for radiation transmission by means of multiple, total external reflection, characterized in that said lens is formed by densely layered miniature lenses, each miniature lens consisting of a plurality of said radiation transmission passages whose diameters are variable in the longitudinal direction of the miniature lens and which define a common single focal point, the total cross-section of each miniature lens is variable in the longitudinal direction of said lens and the central axis of each miniature lens is curved and all or part of the radiation passages are arranged axially symmetrically over the cross-section of said lens. 28. Lens according to claim 27, characterized in that the condition of mirror symmetry with respect to one or two mutually perpendicular axes of the lens cross-section is fulfilled for an aggregate of passages arranged in an orderly manner over the lens cross-section. 29. Lens according to claim 28, characterized in that its passages have straight longitudinal axes. 30. Lens according to claim 28, characterized in that the passages whose longitudinal axis is not aligned with the axis or if they are aligned with only one of the lens symmetry planes in their longitudinal direction, are curved, so that all passages which are equidistant from the said axis or plane and have a cross-section which varies in length corresponding to the longitudinal profile of the lens are also curved. 31. Lens according to claim 27, characterized in that the condition of centric or rotational symmetry with respect to the lens longitudinal axis is fulfilled for an aggregate of passages which are evenly arranged over the lens cross-section. 32. Lens according to claim 31, characterized in that its passages have straight longitudinal axes. 33. Lens according to claim 31, characterized in that all passages of the lens, with the exception of the central passage, are curved and all passages equidistant from the lens longitudinal axis are also curved and have a longitudinally variable cross-section corresponding to the lens longitudinal profile. 34. Lens according to one of claims 27, 28 and 31, characterized in that the passages arranged evenly over the lens cross-section while maintaining axial symmetry are grouped into a number of similar modules (30) which are arranged evenly while maintaining axial symmetry. 35. Lens according to claim 34, characterized in that each of the said modules (3), namely the modules of the first stage, is formed by modules (31) of the second stage with an equal number and the same shape and mutual arrangement as the modules of the first stage. 36. Lens according to claim 34, characterized in that it comprises, in addition to those modules which are modules of the first stage, also modules of higher stages and each module of each preceding stage is formed by modules of a next stage with the same number, the same shape and mutual arrangement as the modules of the first stage. 37. Lens according to claim 34, characterized in that its passages have straight longitudinal axes. 38. Lens according to claim 34, characterized in that the passages whose longitudinal axis is not aligned with the axis or if they are aligned with only one of the lens symmetry planes in their longitudinal direction, are curved, so that all the passages equidistant from the said axis or plane are uniformly curved and have a cross-section that varies in length according to the longitudinal profile of the lens. 39. Lens according to one of claims 29, 32 and 37, characterized in that its passages have parallel longitudinal axes. 40. Lens according to one of claims 29, 32 and 27, characterized in that its passages have a cross-section which is uniformly variable in the longitudinal direction of the lens. 41. Lens according to claim 40, characterized in that its passages are conical. 42. Lens according to one of claims 30, 33 or 38, characterized in that it is funnel-shaped. 43. Lens according to one of claims 30, 33 or 38, characterized in that it is semi-drum-shaped or in a symmetrical or asymmetrical drum shape. 44. Lens according to claim 43, characterized in that its passages form a number of layers arranged around the lens longitudinal axis and which have the same total cross-sectional areas of the passages belonging to said layers, the radii of curvature in the curved passages decreasing from the lens longitudinal axis towards the lens periphery. 45. Lens according to claim 44, characterized in that its passages are formed by inner walls of glass mono- or polycapillaries. 46. Lens according to claim 45, characterized in that the radii of curvature of all curved passages are not greater than Rc = 2d/θ²c, where d is the passage diameter; and θc represents the critical reflection angle for the particles with the lowest energy in the spectrum of the transmitted radiation. 47. Lens according to claim 45, characterized in that the radii of curvature of all curved passages have a minimum value of Rc = 2d/θ²c exhibit, where d is the passage diameter; and θc represents the critical reflection angle for the particles with the highest energy in the spectrum of the transmitted radiation. 48. Lens according to claim 45, characterized in that the radii of curvature of all passages having a curvature are inversely proportional to the number of layers to which said passages belong, the number of said layers being counted from the lens longitudinal axis and not being greater than Rc = 2d/θ²c, where d is the diameter of a single passage; and θc represents the critical reflection angle for the particles with the lowest energy in the spectrum of the transmitted radiation. 49. Lens according to claim 45, characterized in that the curvature of the curved passages is variable in the longitudinal direction of the lens. 50. Lens according to claim 49, characterized in that the curvature of the passages varies uniformly in the longitudinal direction of the lens. 51. Lens according to one of claims 27 to 33, 35 to 38, 41 and 44 to 50, characterized in that it has passages with a spirally reflecting surface. 52. Lens according to claim 51, characterized in that all passages with said spiral surface have the same spiral direction as the spiral surface. 53. Lens according to claim 51, characterized in that it has passages in which its spiral surfaces point in both spiral directions. 54. Lens according to one of claims 27 to 33, 35 to 38, 41, 44 to 50, 52 and 53, characterized in that coatings are applied to the inner walls of the passages, these coatings consisting of at least one layer and together with the walls themselves forming a multi-layered structure with different electromagnetic properties of the layers adjacent to it. 55. Lens according to claim 54, characterized in that the contact surfaces between at least two adjacent media are in the other phase state compared to their base layer. 56. Lens according to one of claims 27 to 33, 35 to 38, 41, 44 to 50, 52, 53 and 55, characterized in that diffraction structures with one or more periods are applied to the inner walls of the radiation transmission passages. 57. Lens according to claim 34, characterized in that each of the modules is a miniature lens. 58. Lens according to one of claims 27 to 33, 35 to 38, 41, 44 to 50, 52, 53, 55, characterized in that the miniature lenses (33) differ from each other in terms of radiation capture angles and focal lengths. 59. Lens according to one of claims 27 to 33, 35 to 38, 41, 44 to 50, 52, 53, 55, 57 and 58, characterized in that it comprises radiation passages which are arranged randomly over its cross-section and which outnumber the ordered lens passages.