RU2708637C1 - Method of analyzing ions by energy, mass and charge and device for its implementation - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to a method and an apparatus for analyzing ions based on energies, masses and charges using electric and magnetic fields and can be used to determine elemental composition, for example, plasma of working medium and in studying surfaces of solid bodies. Energy, mass and charge analysis is performed in tandem of energy analyzer with retarding potential and linear Wien filter, and ions are recorded on detector located at tandem output of two analyzers. Analyzer for energies, masses and charges enables analysis of ion beams both by energy and mass and by charge, when analyzing by masses and charges – to work with non-monoenergetic streams of ions, having a large initial angular spread, which provides a large aperture and aperture ratio of the analyzer.

EFFECT: expansion of functional capabilities of existing energy-mass analyzers.

2 cl, 7 dwg

Description

The invention relates to methods and devices for the analysis of ions by energy, mass and charge using electric and magnetic fields and can be used to determine the elemental composition, for example, the plasma of the working substance and when studying the surfaces of solids.

The main areas of application of ion, energy, mass and charge ion analyzers are: studying the surface of solids, studying the structure of matter and interaction processes in particle collisions in gases and plasmas, plasma problems of geophysics and space physics, in particular, placing the analyzer in an area occupied by plasma.

To analyze the ion flow by several parameters, for example, masses and energies, sequentially located energy and mass analyzers are used.

A known method and device for energy-mass analysis according to the Mattauch-Herzog scheme [Alexandrov M.L., Gall L.N., Sachenko V.D. The method of energy-mass spectral analysis of the composition of substances and a device for its implementation // Patent SU No. 1178257. - IPC H01J 49/30. - Publ. 01/27/1996].

The known method is implemented as follows:

1) carry out spatial separation of the ion trajectories in the vertical direction in energy and the ion beam diverging in both directions is converted into parallel monoenergetic ion groups in a toroidal electrostatic analyzer;

2) carry out the separation of ions by mass in the horizontal direction and the focusing of parallel beams at the points of the focal surface coinciding with the detector in a magnetic analyzer with a uniform field;

3) register in the mutually orthogonal directions the energy and mass spectra of the analyte with a spatially extended detector.

The signs of the known method, coinciding with the essential features of the proposed method are:

1) carry out spatial separation of ion trajectories by energy;

2) carry out the separation of ions by mass;

3) register the energy-mass spectrum of the analyzed ion flow.

The disadvantages of this method are:

1) the analysis by mass is carried out when working only with monoenergetic groups of ions of the initial beam; the possibility of mass analysis of groups of ions with a wide continuous energy spectrum is absent due to mixing of ions of different energies at the detector;

2) an increase in the width of the spectrum in energy in the initial ion groups leads to the need to increase the area of creation of a uniform magnetic field of the magnetic analyzer, which leads to an increase in its dimensions;

3) there is no possibility of determining the charge composition in the ion flow.

The device according to the patent [Aleksandrov M.L., Gall L.N., Sachenko V.D. The method of energy-mass spectral analysis of the composition of substances and a device for its implementation // Patent SU No. 1178257. - IPC H01J 49/30. - Publ. 01/27/1996] contains a sequentially located ion source, an electron-optical lens of vertical focusing, a slit diaphragm located in the focus of an electron-optical lens of vertical focusing, an electron-optical lens of horizontal focusing, an output slit of an ion source mounted in the front horizontal focus of the electrostatic toroidal analyzer , electrostatic toroidal analyzer, magnetic analyzer with a uniform field and a spatially extended particle detector with a device stvom reading information.

Signs of a known device that matches the essential features of the claimed device are:

1) energy analyzer;

2) detector.

The disadvantages of the known device are:

1) a narrow input aperture of the device, which is determined by the size of the mandatory vertical and horizontal slots installed in front of the electrostatic toroidal analyzer;

2) a large-sized region with a uniform magnetic field in the magnetic analyzer, the size of which is determined by the area of parallel monoenergetic ion groups formed after passing through the electrostatic toroidal analyzer;

3) the presence of a spatially extended particle detector located in the zone of the edge magnetic field of the magnetic analyzer leads to a deterioration in the mass resolution of the device and complicates the information reading system.

A known method of analyzing ions by energy and mass and a device for its implementation [Strokin N. A., Astrakhantsev N. V., Bardakov V. M., Vo Ny Zan, Kichigin G. N., Lebedev N. B. The method of analysis of ions by energies and masses and a device for its implementation // Patent RU No. 2459310. - IPC H01J 49/00. - Publ. 02/10/2012. - Bull. No. 23].

The known method is implemented as follows:

- analysis of ions by energies and masses is carried out in the combined radial electric field of the Yuza-Rozhansky energy analyzer (UR) and the magnetic field of the Wien sector filter (EF) and the longitudinal electric field of the sector EF transverse to them,

- establish the intensity of the radial electric field E ₀ energy analyzer, setting the energy of ions moving along an equilibrium (axial) circle,

Where:

V _ϕ0 is the particle velocity on the equilibrium trajectory,

R is the radius of the equilibrium circle,

- set the magnitude of the magnetic field induction and the electric field strength of the sector PV so that the particle’s velocity along the equilibrium path is V _ϕ0 and there is no particle motion along the Z axis transverse to the direction of flow:

Where:

In - the induction of the magnetic field of the combined sector PV,

E _z - the electric field strength of the sector PV,

c is the speed of light

- carry out the analysis of ions by mass, changing at fixed E ₀ and B the magnitude of the electric field strength of the sector PV E _z to highlight the mass m _i in accordance with the equation

- measure the distribution of ions in energy for the flow of ions of the same mass,

- the angle of rotation of the analyzed ions is set from the condition for focusing the ions under the action of a combination of three electromagnetic fields.

The signs of the known method, coinciding with the essential features of the proposed method are:

- carry out the analysis of the ion flow by energy,

- carry out the analysis of the flow of ions to the masses,

- set the magnitude of the induction of the magnetic field and the electric field strength of the PV such that there is no movement of the ion along the Z axis transverse to the direction of flow of the stream,

- carry out the analysis of ions by mass, changing at a fixed induction of the magnetic field In the magnitude of the electric field strength PV,

- measure the distribution of ions in energy for the flow of ions of the same mass.

The disadvantages of this method are:

- mass analysis is carried out for a monoenergetic ion beam,

- there is no possibility of determining the charge composition of the ion beam.

The device according to the patent [Strokin N.A., Astrakhantsev N.V., Bardakov V.M., Vo Ny Zan, Kichigin G.N., Lebedev N.V. The method of analysis of ions by energies and masses and a device for its implementation // Patent RU No. 2459310. - IPC H01J 49/00. - Publ. 02/10/2012]:

- contains a sector PV, an energy analyzer, and an ion detector;

- the energy analyzer of the RF and PV is arranged so that the magnetic poles of the PV cover the yyllindric plates of the energy analyzer of the RF, and the PV plates that create the electric field are made in the form of flat electrodes placed on both sides relative to the energy analyzer of the RF and the magnetic system of the PV;

- the ion detector is located at the point of rotation of the trajectory by an angle

ϕ = π / ω,

Where:

ω is a parameter that determines the angle at which the target ions are focused on the equilibrium path,

and cylindrical electrodes are made with a distance between them equal to

Where:

γ is a parameter that determines the angle at which non-target ions go as far away from the equilibrium trajectory as possible.

Signs of a known device that matches the essential features of the claimed device are:

- the device contains PV,

- the device contains an ion detector.

The disadvantages of the known device are:

- a small input aperture of the device, which determines a small allowable angular spread:

Where:

m ₀ is the mass of the setting (central) of the Wine filter,

δm = mm ₀ - range of the analyzed masses.

The prototype of the proposed method and device is the method and device according to the patent [Strokin N.A., Astrakhantsev N.V., Bardakov V.M., Kichigin G.N., Lebedev N.V. The method of analysis of ions by mass and a device for its implementation // Patent RU No. 2431214. - IPC H01J 49/48. - Publ. 10/10/2011. - Bull. No. 28].

The prototype method is implemented as follows:

- carry out the selection of ions of a given energy using an energy analyzer,

- in the PV create a mutually orthogonal electric field and a uniform magnetic field directed along the plates creating an electric field,

- introduce ions into the PV,

- register ions at the detector located at the output of the PV.

The signs of the method according to the prototype, coinciding with the essential features of the proposed method are:

- carry out the allocation of ions of a given energy,

- in the PV create a mutually orthogonal electric field and a uniform magnetic field directed along the plates creating an electric field,

- introduce ions into the PV,

- register ions at the detector located at the output of the PV.

The disadvantages of the prototype method are:

- mass analysis is carried out for a monoenergetic ion beam,

- there is no possibility of determining the charge composition of the ion beam.

The device according to the prototype [Strokin N.A., Astrakhantsev N.V., Bardakov V.M., Kichigin G.N., Lebedev N.V. The method of analysis of ions by mass and a device for its implementation // Patent RU No. 2431214. - IPC H01J 49/48. - Publ. 10/10/2011. - Bull. No. 28] contains:

- energy analyzer,

- Wines filter placed sequentially behind the energy analyzer,

- an ion detector located at the output of the PV.

The signs of the device according to the prototype, coinciding with the essential features of the claimed device are:

- Wine filter,

- ion detector.

The disadvantages of the device of the prototype are:

- a small allowable angular spread of the ion flux, which determines a small input working aperture of the device.

When creating a method for analyzing ions by energies, masses and charges, and a device for its implementation, united by a single inventive concept, the task was to create as a result such a method and device in which all the positive qualities of the prototype method and device would remain and the flow analysis was provided ions both in energies and masses, and in charges, and in the analysis of masses and charges, it was possible to work with non-monoenergetic ion beams having an initial angular spread, which allows Flashes to increase the aperture of the device without increasing its size.

The technical result is achieved by the fact that in the method of analyzing ions by energy and mass, including analyzing the energies in the energy analyzer, analyzing the masses in crossed electrical and uniform, directed along the plates creating the electric field, the magnetic field of the PV and registering the ions at the detector located on the output of the PV, according to the invention, the analysis of energies, masses and charges is carried out in tandem of a sequentially located energy analyzer with a retarding potential (EES) and PV, and the ions are recorded in the detector Åre is located at the outlet of the tandem of the two analyzers.

The technical result is achieved by the fact that in the device for analyzing ions by energy, mass and charge, containing an EZP, PV and ion detector, according to the invention, an energy analyzer with a delay potential is located in front of the Wien filter, and the ion detector is located at the output of the Wien filter; the areas of the analyzing fields of the energy analyzer with a delay potential and the Wien filter are separated by electrostatic and magnetic screens, and the detector is made with an input window, the area of which is larger than the area of the output aperture of the Wien filter.

The advantages of the inventive analyzer in terms of energy, mass and charges compared to the prototype are the ability to analyze ion beams both in terms of energy and mass, and in charges, while in analysis of mass and charges - work with non-monoenergetic ion flows having an initial angular spread, which determines large the analyzer aperture and aperture, which are ensured by the fact that the analysis of energies, masses and charges is carried out in the longitudinal electric field of the EZP and homogeneous crossed PV electric and magnetic fields, an energy analyzer with rzhivayuschim potential have to PV, and the ion detector is positioned on the output PV.

The new functions realized by the claimed method and device, including its ability to work as an analyzer in both energies and masses and charges, and in analyzing masses and charges, to work with non-monoenergetic ion flows having an initial angular spread, allows us to consider the claimed device in a new quality - analyzer for energies, masses and charges.

The inventive method for analyzing ions by energies, masses and charges and a device for its implementation are illustrated by the drawings shown in FIG. 1-7.

In FIG. 1 schematically depicts the claimed device and gives the designation of the analyzing fields and the geometric elements necessary for the implementation of the method and device: E is the electric field between the plates of the capacitor in the region of the flow of the analyzed PV ion; B — magnetic field induction between the plates of the capacitor in the region of the flow of the analyzed PV ions; 1 - energy analyzer with a delay potential; 2 - Wine filter; 3 - detector; C1 - input mesh of the EZP; C2 - separation grid of the EZP; C3 - analyzing mesh of EZP.

In FIG. 2 shows an embodiment of the EZP of the claimed device: 4 - housing; 5 - input grid; 6 - separation grid; 7 - analyzing grid; 8 - collector; 9 - insulators.

In FIG. 3 shows the embodiment of the PV and the characteristic dimensions of the PV are shown: 10 — permanent magnet —; 11 - pole tip; 12 - insulator electrical input; 13 - plate analyzing capacitor; 14 - magnetic circuit; the distance between the plates of the capacitor, for example, 6 mm; the distance between the pole pieces of the magnets, for example, 16 mm; the length of permanent NeFeB magnets, for example, L = 50 mm.

In FIG. Figure 4 shows an example for embodiment No. 1 of current I from the detector (delay curve) when registering a three-component ion flux having a wide energy spectrum W from the minimum energy in the spectrum W _min to maximum W _max , with masses m ₁ , m ₂ and m ₃ with a fixed PV setting when the potential of the analyzing (C3) grid U _en EZP changes from zero to a value eU _an.max > W _max , which ensures that all ions of the incident stream are _blocked .

In FIG. 5 shows for example a wide range of ions in energy from a minimum W _min to a maximum W _max . The spectrum was measured at the output of a plasma accelerator with an anode layer at a discharge voltage of 1100 V, magnetic induction at the anode of 970 G, and argon - plasma-forming gas pressure P = 9⋅10 ^-5 Torr.

In FIG. Figure 6 shows the trajectories of singly and doubly charged krypton ions in the analytic space of the Wien filter — in the region of constant uniform fields transverse to the direction of ion motion.

In FIG. Figure 7 shows the trajectories of single, double, and triple charged xenon ions in the analyzing space of the Wien filter.

The device (Fig. 1) contains an EZP (position 1), PV (2) and an ion beam detector (3). The pole pieces of the PV are made of soft magnetic steel and are used to align the magnetic field over the entire area of permanent NeFeB magnets. An optimized pole shape provides focusing of the ion flow in a plane perpendicular to the flow velocity. Permanent magnets are used to reduce the size of the PV. Such a PV can be placed in a vacuum volume and used, for example, for the diagnosis of multicomponent plasma flows. The possibility of changing the PV setting remains - with the help of an electric field.

The following is a brief theoretical justification for the possibility of implementing the method and creating a device (Fig. 1) for this application.

The Wine Filter is “short”: length, for example, L = 50 mm; the detector is placed directly at the output of the PV. This is explained by the need to have a large aperture of the device. This property of the analyzer is mandatory when registering ions propagating in multicomponent flows and having not linear, but three-dimensional motion trajectories. In addition, the length of the PV is as small as possible. The detector is also chosen wide-aperture with an input window, the area of which overlaps the output gap of the PV, for example, a secondary emission multiplier VEU-6.

An energy analyzer with a retarding potential is located in the zone of scattered magnetic fields of the PV, but, due to the decisive influence on the movement of ions in the EZP region of the electric field between closely spaced EDS grid electrodes, the distortion of the ion paths in the EZP by the scattered PV magnetic field can be neglected. In addition, the EZP and the PV are separated by a magnetic core wall having an entrance slit for introducing the flow into the PV.

The input grid C1 of the EES has zero potential (grounded) and separates the electric fields of the EES and plasma.

Ions at the entrance to the EZP have a wide spectrum of energies (see the example-illustration in Fig. 5) and can move, including in the plasma stream. We do not consider the case of monoenergetic ion beams when the EZP-PV tandem is not needed, but one PV is enough.

When applying a negative potential U _C2 to the grid C2, such that

eU _C2 > W _e ,

Where:

W _e is the plasma electron energy,

the electrons are reflected in the region between the grids C1 and C2 of the energy analyzer and are neutralized on its walls. In the region C2-C3 only the ion flux moves.

Let the PV be tuned to a specific, so-called drift velocity, which can be selected for an ion in the beam whose mass is known (predicted),

Where:

ν ₀ - PV tuning speed (drift velocity),

E is the electric field strength in the analyzing space of the PV,

In - the induction of a magnetic field in the analyzing space PV.

On the analysis grid of the EES, the potential is zero (not supplied).

Ions having a velocity ν ₀ pass through the PV to the detector. An ion of mass m ₁ passing through the PV has energy

If ions have a wide energy spectrum, not only ions with mass m ₁ , but also all other ions in the beam for which the condition

or subject to (1), (2)

At the detector located at the output of the PV, a mixture of ions m ₁ ... m _k will come; the registration system will give a total maximum current signal - there will be no mass separation m ₁ ... m _k .

. Часть ионов, кинетические энергии которых меньше соответствующих анализирующему напряжению величин eU_aнk, отражаются в пространство между сетками С3 и С2 ЭЗП и нейтрализуются на его стенках. Прошедшие через сетку С3 ионы доускоряются в промежутке С3-входная диафрагма (щель) ФВ, которая находится под нулевым потенциалом (заземлена), до энергий, которые они имели на входе в ЭЗП; энергетический спектр прошедших через ЭЗП частиц, таким образом, не изменяется при вариации U_aн.When applied to analyzing the grid C3 EZP positive voltage U _en ions incident flow inhibited; their energies become equal to W _0k = W _0k -eU _ank . The ion velocities before C3 change as

. Some ions whose kinetic energies are less than the values eU _ank corresponding to the analyzing voltage are reflected into the space between the C3 and C2 networks of the EZP and are neutralized on its walls. The ions passing through the C3 grid are accelerated in the gap by the C3-input diaphragm (gap) of the PV, which is at zero potential (grounded), to the energies that they had at the entrance to the EZP; the energy spectrum of particles passing through the EZP, therefore, does not change with variation of U _an .

.Let it be known that in the ion stream there are ions of three masses: m ₁ , m ₂ and m ₃ , with m ₁ <m ₂ <m ₃ . Ions of mass m ₁ will not disappear on the detector until ions of mass m ₁ with energies from the initial minimum W _min.1 to the tuning energy W ₀ + ΔW, where ΔW is the absolute PV resolution in energies, are reflected by the braking field of the C3 EZP grid. On the delay curve I = ƒ (U _an ), the current under these conditions will be determined as I = I ₁ + I ₂ + I ₃ (see Fig. 4). With further increase of U _en mass ions m ₁ are located from the region PV setting signal from these ions disappears at a rate determined by the energy resolution of the PV. On the delay curve, the current amplitude decreases to the level I = I ₁ + I ₂ . At even greater values of U _{an, the} contribution from the ions with mass m ₂ will also disappear and the ion current will be determined only by the current of particles with mass m ₃ . The current from the detector will become zero at eU _en ≥W _max.3 + ΔW. On the delay curve, current steps will be visible, the number of which is equal to the number of different masses of the ions in the incident stream — 3 in our case. Differentiation of the delay curve gives the ion energy distribution - dI / dW, which shows 3 ion peaks, starting with the lightest, at different energies corresponding to ions of three different masses (see Fig. 4). Since the condition for the passage of ions to the detector is known (formula (3)), the values of electric E and magnetic B fields are known, the masses are automatically calculated from the most probable energies obtained for three ion beams:

.

Integration of the distribution functions of the ions extracted by the analyzer gives the particle density of a particular mass.

A Wien filter with parameters L = 50 mm, input and output slit widths d ₀ = d _L = 1 mm at B = 0.25 T, W ₀ = 1 keV has a small energy resolution: R _W ≈2 (ΔW ≈ 500 eV ) An additional advantage of using EZP in tandem with PV is the ability to improve, in comparison with PV only, the energy resolution, defined as the ratio of the half-width of the spectrum at its half height, in certain energy ranges at different stages of scanning.

Thus, the analysis of energies and masses in the analyzer for the flow of ions having a wide spectrum of energies is possible.

To expand the functionality of the analyzer, the EZP - PV - detector can be supplemented by a retractable collector located at the output of the EZP. This will make it possible to measure the total spectrum of all ions by energy before analysis by mass and charge, determine the energy range W _max - W _min , the most probable energy, and see the features of the spectrum. This information will be useful in adjusting the PV and analysis of ions by mass and charge.

It is known that a “short” PV with mutually perpendicular analyzing fields, in which the geometrical length of the motion paths during the cycloid for single and multiply charged ions is much greater than the length of the PV (for illustration see Fig. 6), practically cannot distinguish ions of the same mass, moving at the same speed, but having different charges. For example, for the PV described in FIG. 3, both single- and doubly charged krypton ions Kr ⁺ and Kr ²⁺ with an energy of 1 keV pass (and mix) through the PV with an exit slit 0.8 mm wide at 68 V <U _PV <74 V; only Kr ⁺ passes when 68 V <U _PV <69 V and 74 V <U _PV <76 V. It can be seen that the transmission range for Kr ²⁺ lies within the Kr ^{+ +} transmission range and, thus, overlapping transmission ranges are predominantly observed, therefore, there is the problem of the allocation of ions of the same mass having different charges.

There is a practically important task of elucidating the formation mechanism of the ion distribution function in the stream generated by a plasma accelerator, a plasma engine designed for spacecraft. Xenon, which has one-, two- and three-fold ions (Xe ⁺ , Xe ²⁺ , Xe ³⁺ ), is more often used as a plasma-forming gas. Through the PV (Fig. 3), ions pass at the following voltages between the plates:

Xe ⁺ : 53.70 V≤U _PV ≤61.38 V;

Xe ²⁺ : 55.62 V U U _PV 59 59.46 V;

Xe ³⁺ : 56.26 V≤U _PV ≤58.82 V.

с учетом абсолютного разрешения ФВ по энергиям ΔW. Трудности в данном случае связаны с тем, что придется регистрировать малые токи ионов, так как названные настройки подразумевают работу на хвостах функции распределения ионов по энергиям.It can be seen that the Xe ³⁺ transmission range lies within the Xe ⁺ and Xe ²⁺ transmission ranges; the range of passage of Xe ²⁺ (see Fig. 7) lies within the range of passage of Xe ⁺ . With great difficulties, which are associated with a significant energy spread of ion beams and a finite energy resolution of the PV, only a singly charged xenon ion can be distinguished. It should be noted that, theoretically, the lightest and heaviest ions can also be distinguished from a wide spectrum if the PV settings are made, respectively, by

taking into account the absolute resolution of the PV in energies ΔW. The difficulties in this case are associated with the fact that it is necessary to register small ion currents, since the above settings imply the work on the tails of the ion energy distribution function.

; ток детектора максимальный.When the analyzer registers an ion flux with different charges, with a known identical mass m, having a wide energy spectrum, when there is no delay potential U _an on the C3 EZP analysis grid, and the PV is tuned to the energy W _{0 of a} singly charged ion, ions with all multiplicities of charge whose energies satisfy the condition

; detector current maximum.

With increasing U _an ion with a large charge in the electric field, the EZP will slow down more strongly, since the force acting on the ion, F = qE _{an, is} directly proportional to its charge q and the electric field strength E _en between the analyzing C3 and C2 decoupling networks of the EZP. When eU _{the An} ≈ W _0/3 + ΔW from PV aperture leave ions with q = 3; when _{the An} eU ≈ W _0/2 + ΔW - go ions with charge q = 2; if the value eU _an ≈ W ₀ + ΔW - is reached and ions with q = 1 exit the PV aperture. Thus, the detector current in the presence of ions with different charge multiplicities with increasing U _en will decrease stepwise (the delay curve will be similar to that shown in Fig. 4). The maximum charge ratio will be equal to the number of steps on the delay curve. The amplitude of the current steps will be proportional to the content in the flux of ions with different charge multiplicities. Differentiation of the delay curve will give a quantitative characteristic - the density of ions with different charge multiplicities.

Thus, the analysis of charges in the analyzer for the flow of ions with different charges, with a known identical mass m, having a wide energy spectrum, is possible; In this case, the tandem of the electron-beam condensation plus PV becomes an analyzer of the “charge multiplicity” of the ion flux.

The inventive method is implemented as follows.

A multicomponent ion flux having different energies is introduced into the EZP through the C1 network (Fig. 1), which has zero potential, which shields the analyzer's electrostatic field from the fields in the plasma in the area in front of the EZP.

A negative potential U _C2 , such that eU _C2 > W _e , is fed onto the grid C2 of the EES. The electrons that penetrated through the C1 grid reflect the inhibiting electric field into the area between the grids C1 and C2 of the energy analyzer, where they are neutralized on the walls.

, которая выбирается для иона, масса которого известная (или прогнозируемая).Set the PV to a specific drift velocity

, which is selected for an ion whose mass is known (or predicted).

.The ions passed through the PV are recorded on the detector for which the condition

.

.A positive voltage U an is _{applied to the} analyzing grid C3 of the EZP, thereby inhibiting the ions of the incident stream; their energies become equal to W _0k = W _0k -eU _ank and the ion velocities vary as follows:

.

Part of the ions is reflected into the space between the grids C3 and C2 of the EZP, the kinetic energies of which are less than the values of eU _an.k corresponding to the analyzing voltage.

Ions passing through the C3 grid accelerate in the gap C3 — the input PV diaphragm to the energies that they had at the entrance to the EZP; Thus, the energy spectrum of the transmitted particles does not change with variation of U _an .

In a stream of ions of three masses: m ₁ , m ₂ and m ₃ (m ₁ <m ₂ <m ₃ ), ions of mass m ₁ are recorded at the detector until ions of mass m ₁ with energies from the initial minimum W _min . ₁ to the tuning energy W ₀ , taking into account the energy resolution ΔW. On the delay curve I = ƒ (U _an ), the current under these conditions will be determined as I = I ₁ + I ₂ + I ₃ .

U _an is increased until ions of mass m ₁ leave the area of the PV setting. The signal from these ions disappears at a speed determined by the energy resolution ΔW of the Wien filter. On the delay curve, the current amplitude decreases to the level I = I ₁ + I ₂ .

U _{an is} increased until the contribution from ions with mass m ₂ disappears on the detector and the ion current is determined only by the current of particles with mass m ₃ .

The analysis voltage is increased to eU _an ≥W _max . 3. The detector current will be zero.

The delay curve is recorded, which has a step shape, the number of steps on which is equal to the number of different masses of the ions in the incident stream — 3 in our case.

They differentiate the delay curve, obtaining the energy distribution of ions - dI / dW, which shows 3 ion peaks, starting with the lightest, at different energies corresponding to ions of three different masses (similar to the data shown in Fig. 4).

.Using the most probable energies obtained for three ion beams, the ion masses are calculated by the formula

.

The particle densities of a given mass are calculated by integrating the distribution functions of the ions extracted by the analyzer.

When the analyzer registers an ion flux of the same mass m with different charges having a wide energy spectrum, the inventive method is implemented as follows;

PV is tuned to the energy W _{0 of a} singly charged ion.

.The maximum ion current is recorded on the detector, the contribution to which is made by ions with all charge multiplicities, whose energies satisfy the condition

.

U is increased to a value of _{the An} eU _en ≈ W _0/3 + ΔW.

A decrease in current is recorded on the delay curve due to the departure of ions from q = 3 from the PV aperture.

U is increased to a value of _{the An} eU _{the An} ≈ W _0/2 + ΔW.

A decrease in current is recorded on the delay curve due to the departure of ions with q = 2 from the PV aperture.

Increase U _an to eU _an ≈ W ₀ + ΔW.

A decrease in current is recorded on the delay curve due to the departure of ions with q = 1 from the PV aperture.

Thus, the detector current in the presence of ions with different charge multiplicities with increasing U _an will decrease stepwise (the delay curve is similar to that shown in Fig. 4). The maximum charge multiplicity will be equal to the number of steps on the delay curve. The amplitude of the current steps will be proportional to the content in the flux of ions with different charge multiplicities.

The delay curve is differentiated, obtaining a quantitative characteristic of the ion flux — the density of ions with different charge multiplicities.

The inventive device operates as follows.

The device contains an EZP (position 1 in Fig. 1), PV (2) and an ion detector (3). EZP is located in front of the PV. The ion detector is located at the output of the PV. EZP and PV are made with large input apertures, which makes it possible to increase the analyzer sensitivity and register particles that have three-dimensional trajectories. The Wine Filter is made short: length L = 50 mm; an ion detector is placed directly at the output of the PV. The areas of the analyzing fields of the EZP and PV are separated by electrostatic and magnetic screens. The detector is made with an input window, the area of which is larger than the area of the output diaphragm-gap PV.

Thus, the inventive analyzer provides diagnostics for energies, masses and charges both in the presence of ions of the analyzed flow of energy and angular dispersion.

Claims (2)

1. The method of analysis of ions by energy and mass, including energy analysis in an energy analyzer, mass analysis in crossed electrical and uniform, directed along the plates creating an electric field, magnetic field of the Wien filter and registration of ions at the detector located at the output of the Wien filter, characterized in that the analysis of energies, masses and charges is carried out in tandem of a sequentially located energy analyzer with a delay potential and a Wien filter, and the ions are recorded on a detector located and the output of the two tandem analyzers. 2. A device for analyzing ions by energy, mass and charge, comprising a Wien filter and an ion detector, characterized in that an energy analyzer with a delay potential is located in front of the Wien filter, and an ion detector is located at the output of the Wien filter; the areas of the analyzing fields of the energy analyzer with a delay potential and the Wien filter are separated by electrostatic and magnetic screens, and the detector is made with an input window, the area of which is larger than the area of the output aperture of the Wien filter.

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