RU2364004C1 - Power filter for corpuscular-optical system of image construction and transmission - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention relates to corpuscular-optical instrument making. Power filter (PF) comprises the first magnetic deflector (MD1) with optical axis shifted through 90°, first matching lens unit (MLU₁), power analyser (PA), second matching lens unit (MLU₂), second magnetic deflector (MD₂) and power diaphragm (PD). PF input arm represents the first input arm of MD_1, its first optical axis passing from the first input to first output of MD₁. First output arm of MD₁ and input arm of PA are located on the axis MLU₁. PA output arm and MD₂ are located on MLU₂ axis. MD₂ output arm is aligned with the first input arm of MD₁, while PA is located on PF. The nit of guide lens (UGL) is located between MD₁ and MD₂. MLU₁, MLU₂ and UGL represent axially symmetric lenses. MD has two inputs, two outputs and three optical axes. Note here that MD second input is located on straight line aligned with its first input arm. Its second input is located on the straight line aligned with its first output arm. MD₁ is connected to variable-polarity power source. MD₂ output arm is directed toward MD₁ while MD₁ output arm makes output arm of PF. MLU₁ and MLU₂ can accommodate retarding and accelerating lenses. PA can be built around semi-spherical condenser.

EFFECT: expanded performances due to power dispersion in wide range.

7 cl, 2 dwg

Description

The invention relates to corpuscular-optical instrumentation and can be used in the design of corpuscular-optical systems for the formation and transmission of images (KOSPPI) with the possibility of energy filtration and / or precision energy analysis. Preferred fields of its use are emission electron microscopy and energy spectroscopy of micro- and nanotechnology objects, specular electron microscopy, secondary emission ion microscopy, micro- and nanolithography, and also time-of-flight electron energy spectroscopy and microscopy.

Known energy Omega filter for KOSPPI, the input and output shoulders of which are located on the optical axis of the said particle-optical system, containing installed in the direction of image transmission, the first magnetic deflector (MD ₁ ), an energy analyzer formed by magnetic sectors, the second magnetic deflector (MD ₂ ) and energy diaphragm (ED). MD ₁ performs the function of directing the information corpuscular beam (ICP) to the energy analyzer (hereinafter, ICP refers to the corpuscular beam transmitting an image of the studied area of the sample surface or diffraction pattern formed in the focal plane of the KOSPPI lens and containing information about the crystal structure of the studied sample, or transmitting information about the energy spectrum of electrons emitted from the surface of the sample), and MD ₂ - the direction of the ICP from the output of the energy analyzer to registration KOSPPI on-screen (RE) (see, for example: EP 0218920, H01J 37/05, 37/26, 37/04, 49/44, 49/00, 1988; JP 7282773, H01J 37/05, 37/26, 37/04, 49/44, 49/40, 1995; US 6307205, H01J 37/05, 37/04, 49/44, 49/48, 49/42, 49/00, G21K 1/093, 1/00 , 2001). In this technical solution, the input arm of MD ₁ coincides with the input arm of the energy filter, and the output arm of MD ₂ coaxial to the input arm of MD ₁ and serves as the output arm of the energy filter. The design of this energy filter allows you to disconnect it from KOSPPI without changing the further direction of transmission of the corpuscular image, which provides the possibility of image transmission with the connection of the energy filter for energy filtration or energy spectroscopy, and bypassing the energy filter, which simplifies the configuration of the corresponding KOSPPI.

Nevertheless, this design has the following disadvantages: the impossibility of varying the energy dispersion in the modes of energy filtration or energy spectroscopy and the complete absence of energy dispersion when working with the power filter turned off.

An energy filter for KOSPPI is also known, where a spherical electrostatic capacitor is used as an energy analyzer. Here, as in the Omega filter, the output and input optical axes of the energy filter are aligned, however, unlike the Omega filter, the curved section of the optical axis of this energy filter is a closed loop with a total rotation angle of 360 °. MD ₁ and MD _{2 are} structurally combined. To ensure energy filtration, a dispersion screen is installed in the electrostatic field of the capacitor (US 2005285032, H01J 37/05, 37/04, 49/48, 49/00, 47/00, 2005).

The disadvantages of this technical solution are the inevitable distortion of the transmitted image due to perturbation of the capacitor field by the dispersion screen, and the inefficiency of the latter.

Meanwhile, modern methods of spectroelectron microscopy require the provision of two alternative energy dispersive modes:

a) energy spectroscopic mode with high-precision energy filtration of transmitted corpuscular images, which requires a large energy dispersion of the energy filter;

b) the energy spectrographic mode of displaying the studied energy spectrum on the RE, requiring a significant reduction (but not to zero!) of the energy dispersion of the energy filter.

Closest to the claimed technical essence is an energy filter for KOSPPI, the input and output shoulders of which are located on its optical axis, containing MD ₁ mounted in the image transmission direction, made with the optical axis rotated 90 °, the first block of matching lenses (BSL ₁ ), energy analyzer, the second block of matching lenses (BSL ₂ ), MD ₂ and ED. The input arm of the energy filter is the first input arm of MD _1. The first optical axis in MD ₁ passes from the first input to the first output. The first output arm MD ₁ and the input arm of the energy analyzer lie on the optical axis of the BSL ₁ , the output arm of the energy analyzer and the input arm of MD ₂ lie on the optical axis of the BSL ₂ , the output arm of MD _{2 is} aligned with the first input arm of the MD ₁ , and the ED is mounted on the output arm of the energy filter, which is the output arm of MD ₂ . In the prototype, the total angle of rotation of the optical axis of the energy filter is zero, the energy analyzer is composed of two magnetic sectors arranged in series, each of which has an optical axis deviation angle of 90 °,

BSL ₁ and BSL _{2 are} composed of quadrupole lenses for sequential correction of astigmatism of the transmitted image; MD _{1 is} installed to match the input optical axis of the energy filter with the optical axis of the energy analyzer, and MD _{2 is} inserted into the energy filter to match the optical axis of the energy analyzer with the optical axis of KOSFPI (EP 0967630, H01J 37/05, 37/153, 37/26, 37/04, 49/46, 2000).

However, the prototype has a low energy dispersion. In addition, it does not allow varying the values of this dispersion, which has the consequence of limiting the possibilities of its use.

The technical task of the invention is the expansion of the functions of the energy filter by creating possibilities for varying the coefficient of its energy dispersion in a wide range.

The solution to this technical problem consists in the fact that in the energy filter for KOSPPI, the input and output shoulders of which are located on its optical axis, containing MD ₁ located in the direction of image transmission, made with the optical axis rotated 90 °, BSL ₁ , energy analyzer, BSL ₂ ,

MD ₂ and ED, in which the first optical axis MD ₁ passes from the first input to the first output MD ₁ , the first output arm MD ₂ and the input arm of the energy analyzer lie on the optical axis BSL ₁ , the output arm of the energy analyzer and the input arm MD ₂ lie on the optical axis BSL ₂ , the output arm of MD _{2 is} aligned with the first input arm of MD ₁ , and the ED is mounted on the output arm of the energy filter, changes are made:

1) an additional guide lens unit (BNL) has been introduced, made on the basis of axisymmetric electronic lenses and installed between MD ₁ and MD ₂ coaxially to the output arm of MD ₂ for optical pairing of the corresponding main points of MD ₁ and MD ₂ in the image transmission mode through an energy analyzer;

2) BSL ₁ and BSL _{2 are} made on the basis of axisymmetric electronic lenses based on the optical conjugation of the center point of the energy analyzer and the corresponding main points MD ₁ and MD ₂ ;

3) MD _{1 is} made with two inputs, two outputs and three geometrically identical optical axes, moreover:

- the second entrance is located on a straight line, coaxial to the first input shoulder;

- the second exit is located on a straight line, coaxial to the first output shoulder;

- the second optical axis passes from the second input to the second output;

- the third optical axis passes from the first input to the second output;

4) MD _{1 is} electrically connected to a current source equipped with a polarity switch;

5) the output arm of MD _{2 is} directed towards MD ₁ ;

6) as the output arm of the energy filter is the second output arm of MD ₁ .

The specified set of known and new distinguishing features is necessary and sufficient for the functioning of the proposed energy filter with the first achieved possibility of electrical control of the energy dispersion coefficient.

The causal relationship of the changes made with the achieved technical result is as follows.

The energy filter operating modes are controlled by switching the magnetic polarity of MD ₁ to the opposite by changing the direction of the current supplying the winding of the magnetic coil of MD ₁ . In this way, the energy filter is ensured in two alternative energy dispersion modes, namely:

1) without passing the ICP energy analyzer (energy spectrographic mode);

2) with the passage of the ICP through the energy analyzer (energy spectroscopic mode).

In the first case, the angular energy dispersion of the ICP when exiting the energy filter becomes minimal (but not zero!), Which makes it possible to display the entire energy spectrum under study in RE or to achieve maximum intensity of the transmitted particle image (in the latter situation, the level of illumination of the particle image and its degree energy filtration is regulated by the size of the ED hole). In the second case, it is possible to carry out high-precision energy spectroscopy of the transmitted corpuscular image.

Compared with the prototype, the functions of MD ₁ and MD _{2 are} changed and supplemented, namely:

- MD ₁ additionally performs new functions: directing the ICP to the RE and creating a minimum energy dispersion of the ICP at the output of the energy filter in the energy spectrographic mode;

- MD ₂ directs the ICP towards MD ₁ (in the prototype MD ₂ sent the ICP to the RE).

A significant increase in the energy dispersion in the energy spectroscopic mode can be achieved by slowing down the ICP before entering the energy analyzer using a retardation lens installed in BSL ₁ . In this embodiment, BSL ₂ includes an accelerating lens, which is necessary to restore the energy of the ICP before it enters MD ₂ (claim 2 of the formula). An additional extension of the range of variation of the energy dispersion in this embodiment is due to the fact that the energy dispersion of the energy analyzer is inversely proportional to the average energy of the ICP passing through it. Therefore, this dispersion can be controlled by the voltage supplied to the extreme electrodes of these lenses closest to the energy analyzer. At the same time, there is an additional opportunity to expand the range of values of this dispersion by varying the optical power of these immersion lenses by changing the voltages at their focusing electrodes.

Energy dispersion takes maximum values if BSL ₁ and BSL _{2 are} set to the intermediate image formation mode, which requires high optical power of BSL ₂ lenses. In this case, it is advisable to establish an additional slotted energy diaphragm (DSED) on the optical axis of the second block of matching lenses to increase the energy resolution (claim 3 of the formula). The installation of the ДДДЭД and the formation of the ICP crossover in its plane make it possible to realize high-precision energy spectroscopy of the transmitted image with maximum transmission, since the dispersion of the energy analyzer is not formed in the direction perpendicular to its middle plane. For a uniform distribution of the illumination of the transmitted image, the ED mounted on the output arm of the energy filter is made with a round hole.

In the technical implementation of the energy filter, a magnetic type energy analyzer with stigmatic focusing can be used as an energy analyzer (see, for example: US 3761707, H01J 49/32, 49/26, 1973; US 6066852, H01J 37/05, 49/44, 49 / 46, 49/48, 37/04, 49/00, 2000). This simplifies the design.

BSL ₁ and BSL ₂ , having removed quadrupole lenses from them, due to the need to perform the function of correcting astigmatism that occurs during image transmission. It is even more advisable to use an electrostatic spherical capacitor as an energy analyzer, which, as you know, provides stigmatism for the transmission of ICPs at any angle of deviation of the optical axis. This embodiment has the simplicity and convenience of regulating the field strength of the energy analyzer (in proportion to the energy of the ICP at its input) by changing the voltage on the plates of a spherical capacitor. In this embodiment, the most appropriate implementation of the energy analyzer based on a hemispherical capacitor (paragraph 4 of the formula). In this case, the maximum energy-dispersion coefficient is achieved, and, as established by the author, the distortion of the particle image due to the action of the edge fields of the capacitor is minimal in this embodiment.

The pole pieces of the magnetic baffles may be flat. However, for flexible adjustment of the mating optical axes, it is advisable to perform MD ₁ and / or MD ₂ with cylindrical boundaries of the pole pieces (claim 5 of the formula).

To further expand the functionality, the energy filter can be additionally equipped with a third magnetic deflector (MD ₃ ), the output of which is connected to the first input of MD ₁ directly or through a block of transporting lenses (BTL) for optical coupling of the output main point of MD ₃ and the input main point of MD ₁ and variation in magnification of the transmitted image; wherein the output arm of MD _{3 is} aligned with the first input arm of MD ₁ (claim 6 of the formula). In this embodiment, the image of the sample is transmitted by the electronic lenses of the KOSPPI lens to the main plane of MD ₃ to ensure achromaticity of the further transmission of the image. By varying the excitations of the lenses included in the BTL, it is possible to electrically control the change in the energy dispersion of the energy filter in the energy spectrographic mode, since the value of the angular dispersion coefficient at the output of the energy filter depends on the value of the optical increase coefficient of the BTL when transferring the particle image from MD ₃ to MD ₁ . The author found that if the polarities MD ₃ and MD ₁ coincide in the energy spectrographic mode, in the variant of transmitting a corpuscular image without the formation of an intermediate image in BTL, the value of the angular energy dispersion coefficient of the energy filter in the energy spectrographic mode is

where K is the coefficient of angular dispersion of the energy filter;

N ₁ and N ₃ are the angular energy dispersion coefficients of MD ₁ and MD _3, respectively;

M is the absolute value of the optical zoom coefficient BTL.

When electrically adjusting the BTL lens excitations corresponding to the transfer of a particle image with the formation of an intermediate image in the BTL, the value of the angular energy dispersion coefficient of the energy filter is

If the polarity of MD _{3 is} set opposite to the polarity of MD ₁ in the energy spectrographic mode, then in the variant of transmitting a particle image without the formation of an intermediate image in BTL, the magnitude of the coefficient of angular dispersion of the energy filter is determined according to formula (2), and when electrically adjusting the excitations of BTL lenses corresponding to the formation of the intermediate image BTL, the value of the coefficient of angular energy dispersion of the energy filter is determined according to formula (1).

Thus, in all these BTL tuning options, the energy dispersion of the energy filter in the energy spectrographic mode can be changed electrically by varying the M value by correspondingly changing the electric excitations of the lenses that make up the BTL. Thus, the range of values of the energy dispersion of the energy filter in the energy spectrographic mode is expanded.

When performing MD ₃ with an additional input and an additional optical axis passing through the geometric conjugation of the additional input and the input arm of the energy filter, for the possibility of connecting an electron gun (EF) to KOSPPI (claim 7), it becomes possible to obtain electronic diffraction patterns containing topographic information about the surface layer of the test sample. In this case, the use of the proposed energy filter allows energy spectroscopy of the diffraction pattern, which gives additional physico-chemical information about the sample under study.

Figure 1 shows a diagram of an energy filter made using claims 1 to 5 of the claims; figure 2 shows a diagram of an energy filter made using claims 1 to 7 of the claims. Places of intermediate images are marked by transverse arrows.

In these examples, MD ₁ and MD _{2 are} made in the form of structures with plane-parallel pairs of magnetic pole pieces symmetrically mounted relative to the middle plane in which the optical axes lie and in which the transverse energy dispersion forms. In the direction perpendicular to the middle plane, there is no energy dispersion. The optical axes of MD ₁ and MD _{2 are} indicated by arcs.

In order to avoid complicating the schemes, well-known details regarding the arrangement of the elements of the energy filter are omitted, and both main points of each of the magnetic deflectors are combined in the optical centers of the latter. In reality, the input and output principal points of MD ₁ and MD _{2 are} somewhat offset from the optical centers. However, these biases are small, since from the optical point of view, MD ₁ and MD ₂ are weak lenses.

In the energy filter (figure 1) for KOSPPI its input a and output e shoulders are mounted on the optical axis of KOSPPI. The energy filter contains MD ₁ (pos. ₁ ) images located in the direction of transmission, made with the optical axis rotated 90 °, BSL ₁ (pos. 2), an energy analyzer (pos. 3), BSL ₂ (pos. 4), MD ₂ ( pos. 5) and ED (pos. 6). The input arm a of the energy filter is the first input arm MD ₁ 1, the first optical axis r ₁ / MD ₁ passes from the first input to the first output MD ₁ , the first output arm b 'MD ₁ and the input arm b "of the energy analyzer 3 lie on the optical axis b of the BSL ₁ , the output arm with 'energy analyzer 3 and the input arm with'

MD ₂ lie on the optical axis with BSL ₂ , the output arm d 'MD _{2 is} aligned with the first input arm a MD ₁ , and ED 6 is mounted on the output arm e of the energy filter. The energy filter additionally contains BNL 7, made on the basis of axisymmetric electronic lenses with the d axis and installed between MD ₁ and MD ₂ (items ₁ and 5, respectively) coaxially to the output arm d 'MD ₂ , BSL ₁ and BSL ₂ (items ₂ and 4 respectively) are made on the basis of axisymmetric electronic lenses, MD _{1 is} configured to form two inputs, two outputs and three geometrically identical optical axes r ₁ , r ₄ and r ₅ , providing the connection of the corresponding inputs and outputs, and in MD _{1 the} second input is located on line d ", coaxial to the first input the shoulder and the second outlet is located on the line e, coaxial with the first output port b ', Optical r ₁ axis connects the first input and an output, the second lens r ₄ axis connects the second input and output, and the third lens r axle ₅ connects a first input and a second output MD _{1 is} electrically connected to a current source (pos. 8) equipped with a polarity switch. The output arm d 'of MD _{2 is} directed towards MD ₁ , and the output arm of the energy filter is the second output arm of MD ₁ .

The energy filter is made using claims 1-5 of the formula, namely:

- in BSL ₁ and BSL ₂ (pos. 2 and 4) there are retarding and accelerating electrostatic lenses, respectively;

- on the optical axis with BSL ₂ installed DSCHED 9;

- a hemispherical capacitor with an optical axis r _{2 is} installed as an energy analyzer 3 _;

- MD ₁ and MD ₂ (items 1 and 5) are made with cylindrical boundaries of the pole pieces;

- on the input shoulder and the energy filter in the plane of the crossover K ₁ installed a removable contrast aperture 10.

In the energy-spectroscopic mode, the ICP enters the input of the energy filter (shoulder a), passes a contrast aperture 10, and enters the first input of MD ₁ (item ₁ ), whose field along the optical axis r ₁ deviates 90 ° to the first output of MD ₁ , acquiring an angular energy dispersion. In this case, the KOSPPI optical elements installed in front of the energy filter (not shown in FIG. 1), the corpuscular image is transmitted to the main plane of MD ₁ , in which its input main point (in the vicinity of the center O ₁ ) is located, which is necessary to ensure the achromaticity of the final image outside depending on the choice of polarity MD ₁ . After exiting MD _1, on the b 'axis, the ICP passes through BSL ₁ (pos. 2) to the input of energy analyzer 3, along the optical axis r _{2 of} which the ICP goes to the c axis, BSL ₂ (pos. 4) passes, in which it restores energy , and arrives at the input of MD ₂ (item 5), the polarity of which is set to the opposite polarity of MD ₁ , after which, along the optical axis, r ₃ rotates through an angle of 90 ° towards BNL 7, going to the d axis, and passing BNL 7 enters for the second time in MD _1, through its second input, along its second optical axis, r ₄ exits through the second output on the e-axis, passes ED 6 and using the projection ion block (not shown) transmits an energy-filtered enlarged particle image on the RE.

In the energy spectrographic mode, in which the studied energy spectrum is displayed on the RE, or in the mode of weak energy filtering of the image in order to achieve its maximum brightness, the magnetic polarity of MD ₁ (item ₁ ) is switched by means of current source 8. In this case, the ICP, entering along the optical axis a ₁ in the MD field moves along a third optical axis r _5, it exits through the second exit to the e axis passes through 6 and ED via a projection unit (not shown), depending on the setting of the latter transmits to the RE enlarged Korpu angles to display the image or on the ER full energy spectrum of the ICP.

The energy filter for KOSPPI, made using claims 1 to 7 of the formula (Fig. 2), is additionally equipped with MD ₃ (pos. 11), the output of which is connected to the first input of MD ₁ (pos. ₁ ) via BTL 12 for optical coupling of the output main points MD ₃ and the input main point MD ₁ and the variation of the magnification of the transmitted image. The output arm a 'MD ₃ coaxial to the first input arm a MD ₁ . The optical axis r ₆ passes with the pairing of the output arm a 'MD ₃ with the input arm ƒ of the energy filter coaxial in this embodiment with the optical axis of the KOSPPI lens. The polarity MD ₃ and MD ₁ in the energy spectrographic mode of operation of the energy filter in this example are the same. MD ₃ is equipped with an additional input and an additional optical axis r ₇ , passing with the geometric conjugation of the additional input and arm ƒ of the energy filter, for the possibility of connecting the ET 13 with the optical axis g to KOSPPI.

IKP e _{1 is} formed as a result of illumination of the test sample by radiation from a light or synchrotron source (not shown) or PEP e ₀ generated by ES 13.

Regardless of the illumination source of the sample generating the ICP, the latter is accelerated by the field of the lens and along the оси axis enters the main input MD ₃ (item 11), which in this embodiment is the input of the energy filter, goes along the optical axis r ₆ to the axis a, and through BTL 12 at the first entrance of MD ₁ (item ₁ ). Further movement of the ICP occurs, as in the example of Fig 1. Due to the optical conjugation of the main points MD ₃ and MD ₁ by BTL 12, the particle image is transmitted to the input main plane of MD ₁ , which is necessary to ensure achromaticity of the transmitted particle image. By changing the electrical excitations of the lenses included in the BTL 12, a variation in the optical magnification M of the transmitted image is provided, and thereby the magnitude of the coefficient of angular energy dispersion of the energy filter in the energy spectrographic mode according to formula (1) is changed.

In the variant of electronic illumination of the sample, the probe E ₀ generated by EP 13 along the optical axis g enters the additional input MD ₃ , is deflected by its magnetic field along the optical axis r _7, and the KOSPPI lens passes along the optical axis,, focusing in its focal plane, is inhibited by the field lens near the sample, and, becoming parallel, coherently illuminates the studied surface of the sample normal to it, generating an ICP with the formation of a diffraction pattern in the focal plane of the lens. This diffraction pattern, like the corpuscular image of the sample, can be transmitted through the energy filter to the RE.

The proposed technical solution, in comparison with the prototype, significantly expands the functions of the energy filter by creating the possibility of varying the coefficient of its energy dispersion electrically in a wide range, which results in achieving the universality of the use of the energy filter in spectroscopic studies. This is illustrated by the possibility of the proposed energy filter in energy spectroscopic and energy spectrographic modes.

A positive effect, derived from the achieved, is the possibility of an alternative image transmission, which greatly simplifies the adjustment of the corresponding KOSPPI due to the autonomous adjustment of the energy filter elements.

In addition, the proposed energy filter has the necessary particle-optical properties to ensure time-of-flight electron microscopy and energy spectroscopy.

The use of the proposed energy filter in emission electron microscope and energy spectrometer and their time-of-flight counterparts can significantly expand the range of obtained physical and chemical information about the test sample.

Claims (7)

1. An energy filter for a particle-optical system for forming and transmitting an image, the input and output arms of which are located on its optical axis, comprising a first magnetic deflector mounted in the direction of image transmission and rotated by 90 °, the first block of matching lenses, an energy analyzer, a second block of matching lenses, a second magnetic deflector and an energy diaphragm, while the first optical axis of the first magnetic deflector passes from the first input to the first output of this the reflector, the first output arm of this deflector and the input arm of the energy analyzer lie on the optical axis of the first block of matching lenses, the output arm of the analyzer and the input arm of the second magnetic deflector lie on the optical axis of the second block of matching lenses, the output arm of the second magnetic deflector is aligned with the first input arm of the first magnetic deflector and the energy diaphragm is mounted on the output arm of the energy filter, characterized in that it further comprises a block of guide lenses based on axisymmetric electronic lenses and mounted between the first and second magnetic deflectors coaxially to the output arm of the second magnetic deflector, the first and second blocks of matching lenses are made on the basis of axisymmetric electronic lenses based on optical conjugation of the center point of the energy analyzer and the corresponding principal points of the first and second magnetic deflectors, the first magnetic deflector is made with two inputs, two outputs and three geometrically identical optical axes and electrically It is connected to a current source equipped with a polarity switch, and in this magnetic deflector the second input is located on a straight line, coaxial to the first input arm, the second output is located on a straight line, coaxial to the first output arm, the second optical axis passes from the second input to the second output, the third optical axis passes from the first input to the second output, while the output arm of the second magnetic deflector is directed towards the first magnetic deflector, and the second output arm of the first magnetic deflector serves as running shoulder of the energy filter. 2. The energy filter according to claim 1, characterized in that in the first and second blocks of matching lenses are installed slowing and accelerating electrostatic lenses, respectively. 3. The energy filter according to claim 1, characterized in that an additional slotted energy diaphragm is mounted on the optical axis of the second block of matching lenses. 4. The energy filter according to claim 1, characterized in that a hemispherical capacitor is installed as an energy analyzer. 5. The energy filter according to claim 1, characterized in that the first and / or second magnetic deflector (s) is made (s) with cylindrical borders of the pole pieces. 6. The energy filter according to claim 1, characterized in that it is additionally equipped with a third magnetic deflector, the output of which is connected to the first input of the first magnetic deflector directly or through a block of transporting lenses for optical coupling of the output main point of the third magnetic deflector and the input main point of the first magnetic deflector and variations in magnification of the transmitted image, wherein the output arm of the third magnetic deflector is aligned with the first input arm of the first magnetic deflector. 7. The energy filter according to claim 6, characterized in that the third magnetic deflector is made with an additional input and an additional optical axis passing with the geometric conjugation of the additional input and input arm of the energy filter, for the possibility of connecting the electron gun to the particle-optical system.

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