RU2459310C2 - Method of analysing charged particles based on energy mass and apparatus for realising said method - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: analysis based on energy and mass is carried out in superimposed radial electric field of a Hughes-Rozhansky energy analyser and the magnetic field if a Wien filter and the longitudinal electric field of the Wien filter which lies across said two fields. The Hughes-Rozhansky energy analyser and the Wien filter are merged in a single structure, the Wien filter being cylindrical. The ion detector and the distance between cylindrical plates are determined by focusing conditions of the target ions.

EFFECT: broader functionalities of charged particle energy-mass analysers.

2 cl, 4 dwg

Description

The invention relates to methods and devices for analyzing ions by energy and mass using electric and magnetic fields and can be used to determine the elemental or isotopic composition, for example, the plasma of the working substance and in the study of the surfaces of solids.

The invention relates to a promising direction in the development of science and technology "Nanotechnology and nanomaterials".

The main fields of application for energy and mass analyzers of charged particles — energy-mass analyzers — are the study of the surface of solids, the study of the structure of matter and interaction processes in particle collisions in gases and plasmas, and plasma problems in geophysics and space physics.

A known method of analysis of charged particles by mass and a device for its implementation [Guenter F. Voss. Mass spectrometer and related ionizer and methods // Patent US 6815674. - IPC H01J 49/28. - Publ. 11/09/2004].

The known method includes:

1) the creation in the work area of mutually perpendicular electric and magnetic fields, and the electric field is not necessarily homogeneous;

2) ionization of the working (analyzed) gas sample by electron impact;

3) the separation of ionized particles in accordance with the ratio of mass to charge, due to movement in electric and magnetic fields perpendicular to each other;

4) registration of ions at the detector.

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

1) the creation in the work area of mutually perpendicular electric and magnetic fields;

2) the separation of ionized particles in accordance with the ratio of mass to charge, due to movement in electric and magnetic fields;

3) registration of ions at the detector.

The disadvantages of this method are:

1) the impossibility of analyzing beams of charged particles having an initial energy spread - during the analysis by mass (for a given value of the ion charge), a monoenergetic particle beam is not provided;

2) the impossibility of analyzing beams of charged particles having an initial spread in the corners - the lack of focusing.

A mass analysis device is known [Guenter F. Voss. Mass spectrometer and related ionizer and methods // Patent US 6815674. - IPC H01J 49/28. - Publ. 11/09/2004].

The device contains:

1) an ionizer;

2) flat parallel electrodes to create an analyzing electric field;

3) a system for creating an analyzing magnetic field whose direction is perpendicular to the direction of the analyzing electric field;

4) detector.

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

1) parallel electrodes to create an analyzing electric field;

2) a system for creating an analyzing magnetic field whose direction is perpendicular to the direction of the analyzing electric field;

3) detector.

The disadvantages of the known device are:

1) the device does not provide the ability to analyze beams of charged particles having an initial energy spread;

2) the device does not provide analysis of beams of charged particles having an initial spread in the corners - it does not have spatial focusing of particles;

3) due to the lack of focusing, the device has a low aperture (sensitivity).

A known method and device for mass analysis [Aleksandrov M. L., Gall L.N., Savchenko 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) the ion beam is decomposed into the spectrum by energy in the transverse relative to the direction of motion of the particles electric field of the electrostatic analyzer;

2) the ion beam expanded in the energy spectrum is affected by a uniform magnetic field of the magnetic analyzer that is transverse relative to the direction of motion of the particles;

3) beam detection is carried out by a spatially extended detector in two mutually perpendicular directions.

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

1) the ion beam is transverse to the direction of particle motion by the electric field of the electrostatic analyzer;

2) the ion beam is transverse with respect to the direction of motion of the particles and the electric field of the electrostatic analyzer by the magnetic field of the magnetic analyzer;

3) carry out the detection of the beam on a spatially extended detector in two mutually perpendicular directions.

The disadvantages of this method are:

1) a small range of energies ΔW of the initial ion beam; for analyzing fields with cylindrical symmetry (on the main trajectory of radius R) with a tuning energy equal to W, ΔW≈W (S ₂ / R) << W, where S ₂ is the width of the exit slit of the energy analyzer;

2) an increase in the spectrum width with respect to the energy of the initial ion beam 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 the heterogeneity of the magnetic field at the boundary of the analyzer and its dimensions.

The device according to the patent [Aleksandrov M.L., Gall L.N., Savchenko 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 sequentially located ion source with focusing lenses, electrostatic toroidal and magnetic with a uniform field analyzers and a spatially extended particle detector with an information reader.

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

1) electrostatic energy analyzer;

2) magnetic analyzer;

3) a detector with a reader.

The disadvantages of the known device are:

1) the sequential inclusion of an electrostatic energy analyzer and a magnetic analyzer increases the dimensions of the device and reduces its aperture (sensitivity), including due to the presence of electromagnetic scattering fields at the boundaries of the analyzers;

2) the presence of a spatially extended particle detector complicates the information reading system.

The prototype of the proposed method and device is the method and device according to the patent [Romaniuk N.I., Papp F.F., Chernyshova I.V., Shpenik O.B. A method for analyzing a beam of charged particles by energy and a device for its implementation (cycloidal analyzer) // Patent SU No. 1756973. - IPC H01J 49/48. - Publ. 08/23/1992].

The prototype analysis method includes:

1) creating a transverse (radial) relative to the direction of motion of the beam of charged particles of the electric field, the equipotential surfaces of which are cylindrical surfaces;

2) the creation of a uniform magnetic field transverse relative to the direction of motion of the beam of charged particles and the direction of the electric field;

3) the introduction of a beam of charged particles into the field of action of crossed radial electric and longitudinal (directed along the cylindrical plates of the capacitor, creating an electric field) magnetic fields;

4) separation of the beam of charged particles having a given mass, according to energy under the action of crossed radial electric and longitudinal magnetic fields;

5) registration of particles at a detector located behind the output diaphragm.

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

1) creating a transverse (radial) relative to the direction of motion of the beam of charged particles of the electric field, the equipotential surfaces of which are cylindrical surfaces;

2) the creation of a magnetic field transverse relative to the direction of motion of the beam of charged particles and the direction of the radial electric field;

3) the introduction of a beam of charged particles in the field of action of crossed radial electric and magnetic fields;

4) registration of particles at a detector located behind the output diaphragm. The disadvantages of the prototype method are:

1) the impossibility of analyzing the energies of beams of charged particles of different masses;

2) the impossibility of analysis by mass of particle beams having different energies.

The device according to the prototype [Romaniuk N.I., Papp F.F., Chernyshova I.V., Shpenik O.B. A method for analyzing a beam of charged particles by energy and a device for its implementation (cycloidal analyzer) // Patent SU No. 1756973. - IPC H01J 49/48. - Publ. 08/23/1992] includes:

1) electrodes to create a transverse direction of the beam of charged particles of the electric field, which are made in the form of a pair of coaxial cylinders;

2) a system for creating a magnetic field, made so that the direction of the uniform magnetic field created by it is perpendicular to both the direction of motion of the beam of charged particles and the direction of the electric (radial) field is directed along the cylindrical electrodes;

3) input and output diaphragms located in the area between the cylindrical electrodes.

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

1) electrodes to create a transverse direction of the beam of charged particles of the electric field, which are made in the form of a pair of coaxial cylinders;

2) a system for creating a magnetic field, made so that the direction of the magnetic field created by it is perpendicular to the direction of motion of the beam of charged particles;

3) input and output diaphragms located in the area between the cylindrical electrodes.

The disadvantage of the prototype device is the lack of spatial focusing of the beam of the analyzed charged particles, which reduces the aperture (sensitivity) of the analyzer.

When creating a method for the analysis of charged particles by energies and masses and a device for its implementation, united by a single inventive concept, the goal was to create such a method and device in which all the positive qualities of the prototype method and device would remain and it was possible to analyze ion fluxes both by mass and energy, when analyzing by mass — the ability to work with non-monoenergetic ion beams having an initial angular velocity spread would increase the aperture ratio ibor and its dimensions decreased.

The technical result is achieved by the fact that in the method of analysis of charged particles by energy and mass, including energy analysis in the electric field of a cylindrical capacitor - Yuz-Rozhansky energy analyzer, mass analysis in crossed electric and magnetic fields of the Wien filter, according to the invention, energy and mass analysis lead in the combined radial electric field of the energy analyzer Yuz-Rozhansky and the magnetic field of the Wien filter and transverse to them longitudinal electric field of the Wien filter, while the angle of rotation analyzed ions is not π / 2 ^0.5 (about 127 °), as in the prior-Rozhansky Hughes energy analyzer and determined by the conditions of focusing the charged particles under the action of a new set of three magnetic fields.

The technical result is achieved by the fact that in the device for the analysis of charged particles by energy and mass, containing the Yuz-Rozhansky energy analyzer and the Wien filter, according to the invention, the Wien filter is cylindrical, the Yuz-Rozhansky energy analyzer and the Wien filter are arranged so that the magnetic poles of the Wien filter cover cylindrical plates of the energy analyzer Yuza-Rozhansky, and plates of the Wine filter that create an electric field are made in the form of flat round electrodes placed on both sides relative to the energy the Hughes-Rozhansky analyzer and the Wien filter magnetic system, while the ion detector is located at the point of rotation of the trajectory by an angle

φ = π / ω,

where ω is the parameter that determines the angle at which the target ions are focused on the equilibrium path, 1 / rad,

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

where γ is the parameter that determines the angle at which non-target ions go as far as possible from the equilibrium trajectory, 1 / rad.

The advantages of the claimed energy mass analyzer compared to the prototype are the ability to analyze ion beams both in energy and mass and in mass analysis - work with non-monoenergetic flows of charged particles having an initial angular velocity dispersion, large aperture of the energy-mass analyzer which are ensured by the fact that the analysis of energies and masses is carried out in the combined radial electric field of the Yuz-Rozhansky energy analyzer and the magnetic field of the Wien filter and the longitudinal electric field transverse to them the Wine filter, the Wine filter is cylindrical, the Yuz-Rozhansky energy analyzer and the Wine filter are arranged so that the magnetic poles of the Wine filter cover the cylindrical plates of the Yuz-Rozhansky energy analyzer, and the Wine filter plates creating an electric field are made in the form of flat circular electrodes placed along both sides relative to the Hughes-Rozhansky energy analyzer and the Wien filter magnetic system, while the ion detector is located at the angle of the trajectory

φ = π / ω,

where ω is the parameter that determines the angle at which the target ions are focused on the equilibrium path, 1 / rad,

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

where γ is the parameter that determines the angle at which non-target ions go as far as possible from the equilibrium trajectory, 1 / rad.

The new functions realized by the claimed device, including its ability to work both as an energy and mass analyzer, when operating in the mass analyzer mode, diagnose non-monoenergetic ion beams having an initial angular velocity dispersion, allow us to consider the claimed device in a new quality - energy-mass analyzer Wines-Hughes-Rozhansky.

The inventive method for the analysis of charged particles by energy and mass and the device for its implementation are illustrated by the drawings shown in figures 1-4.

Figure 1 schematically shows the inventive device and gives the designation of the analyzing fields and geometric elements necessary for the implementation of the method: E ₀ - electric field strength on an equilibrium trajectory of radius R; In _r = BR / r, E _r = -E ₀ R / r.

Figure 2 shows a side view (arrow A in figure 1) of the inventive device.

. Начальный разброс скоростей отсутствует.Figure 3 shows the dependence of the radial deviation of the ion trajectories on the magnitude of the azimuthal velocity component. Accepted

. There is no initial velocity spread.

.Figure 4 shows the dependence of the radial deviation of the ion trajectory on the values of the initial radial and Z-components of the ion velocities at ε = E ₀ / E _z0 = 1; E ₀ , E _z0 - the intensity of the radial and longitudinal analyzing electric fields. Accepted

.

The device comprises (see FIGS. 1, 2) an input diaphragm 1, an axially symmetric system 2 for creating a radial magnetic field B _r , two axially symmetric cylindrical electrodes 3 for creating a radial electric field _Er , two flat electrodes 4, designed to create a homogeneous electric field E _z directed along the axis of cylindrical electrodes (along the Z axis), an output diaphragm 5, and a charged particle beam detector 6.

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

The analyzer is a combination of a Hughes-Rozhansky energy analyzer (UR) with a radial analyzing electric field E ₀ and a Wien filter “rolled” into a cylinder, with a radial magnetic field B _r that is created between the plates of the UR energy analyzer (forming a cylinder) and longitudinal (along cylindrical plates — along the Z axis) with a uniform electric field E _z (see Figs. 1, 2); let's call it the energy-mass analyzer of Wien-Hughes-Rozhansky (FYR).

The equations of motion of a singly charged ion in the energy-mass analyzer of VUR in a cylindrical coordinate system have the form:

where m is the mass of the charged particle, e is the electron charge, and c is the speed of light.

Let us find the conditions on the parameters B, E _z , E ₀ under which the ion entering the region of the analyzing fields at a point with radius R with velocity V _φ0 at V _z0 = V _r0 = 0 remains on the trajectory of radius R and further, when passing through the analyzer .

From equation (1) it follows that

The radial electric field strength E ₀ thus determines the energy of charged particles W ₀ moving along a circle of radius R.

Using equation (3), we set the azimuthal velocity

such that there is no movement along the Z axis. From equations (4) and (5) we obtain the relation:

which shows that for fixed E ₀ and B, ions of different masses will remain on the main trajectory (radius R) if

For positioning on the main trajectory of an ion of mass m _i it is necessary to change E _z in accordance with equation (7) - see figure 2.

In the future, we will consider in detail how until now not implemented in this configuration of electromagnetic fields and electrodes, the most complex is mass analysis.

.We choose an ion of mass m ₀ for which, according to (7), E _{z0 is} chosen. We introduce the parameter ε = Е ₀ / Е _z0 and the variables χ = r / R, ξ = z / R, τ = ω ₀ t, ω ₀ = еВ ₀ / (m ₀ s) (ω ₀ is the Larmor frequency). We write equations (1-3) in a dimensionless form for a particle of mass m ≠ m ₀ that has energy

.

при τ=0, для массы m и энергии W. Кроме того,

The constant in equation (10) is equal to:

at τ = 0, for mass m and energy W. In addition,

Then the ratio for the energies is obtained in the form:

то при условии {τ=0, m, W} получим, чтоSince for m ₀ , W ₀ it follows from (8) that for τ = 0 the derivative

then under the condition {τ = 0, m, W} we get that

Then the constant in (10) is equal to:

 and from equation (10) we obtain the following relation:

Consider the case when the deviations of W from W ₀ and m from m ₀ are small. The initial spreads in the velocities dχ / dτ and dξ / dτ at the time instant τ = 0 are also small. Equations (8-10) in this case will describe the trajectories near the main trajectory:

W = W ₀ + δW, m = m ₀ + δm,

 χ = 1 + χ *.

,

и производным dχ*/dτ, dξ/dτ из уравнений (8-12) получим:At the moment τ = 0 in the first order of smallness with respect to

,

and the derivatives dχ * / dτ, dξ / dτ from equations (8-12) we obtain:

Given that in the first order of smallness

уравнения (13) и (14) записываем так:

equations (13) and (14) are written as follows:

The initial conditions for equations (15), (16) have the form:

χ * (0) = 0, ξ (0) = 0,

The system (15-16) of two linear equations of the second order is reduced to one linear equation of the fourth order:

The initial conditions for equation (17) are of the form:

χ * (0) = 0;

. Для нее получим однородное уравнение:We introduce the function

. For her we get a homogeneous equation:

ρ'(0)=U;

at

ρ '(0) = U;

We solve for (19) the characteristic equation:

;

.

;

.

The general solution of equation (19) has the form:

ρ (φ) = C ₁ e ^γφ + C ₂ e ^-γφ + C ₃ cos (ωφ) + C ₄ sin (ωφ).

The integration constants C ₁ , C ₂ , C ₃ , C _{4 are} determined from the initial conditions (20):

Based on these results for the ion trajectory, we obtain the following equation:

с учетом которых получим следующее выражение:

We introduce the notation

taking into account which we obtain the following expression:

и

Возьмем частицы, которые удовлетворяют таким условиям. Тогда для их траекторий получим следующее уравнение:As can be seen from equation (21), the ion crosses a trajectory of radius R (about χ * = 0) if b ₁ = 0 and b ₂ = 0, which can happen (see Fig. 3) for certain values of δm / δW and U / V, namely when

and

We take particles that satisfy such conditions. Then for their trajectories we obtain the following equation:

возвращение к χ*(φ)=0 (на радиус R) будет при

В случае

выбранные частицы сфокусируются при следующем значении угла:At

a return to χ * (φ) = 0 (by radius R) will be for

When

the selected particles will focus with the following angle:

частицы с

отходят от положения χ*(φ)=0 на максимальное расстояние, равное

. Это означает, что приемник ионов в энерго-масс-анализаторе необходимо располагать в точке поворота траектории иона на угол φ₁=π/ω, на котором целевые ионы с δm=δW=0 фокусируются, а ионы с δm≠0 максимально отходят от основной траектории χ*(φ)=0.At the focal points of ions with

particles with

deviate from the position χ * (φ) = 0 by a maximum distance equal to

. This means that the ion receiver in the energy-mass analyzer must be placed at the turning point of the ion path at an angle φ ₁ = π / ω, at which target ions with δm = δW = 0 are focused, and ions with δm ≠ 0 are maximally removed from the main trajectories χ * (φ) = 0.

их траектории определяются величиной δW/W. Пусть значение δW/W=-А_m. Различным δW/W соответствуют траектории двух классов. При δW/W<-А_m величина b₁<0, и ионы, не возвращаясь к χ*=0, уходят при φ→∞ на -∞ по χ*. Однако при δW/W>-А_m величина b₁>0, и ионы некоторое количество раз возвращаются к χ*=0, а при φ→∞ уходят на +∞ по χ*. Обязательно найдется такое значение δW/W, которое лежит в области

, и при котором траектория иона с

пройдет через χ*=0 при φ=φ₁. Это означает, что в детектор будут попадать ионы и других, кроме m₀, масс и для разделения ионов использование только сепарирующих возможностей данного набора электромагнитных полей недостаточно.We turn to the case when b ₁ ≠ 0, but the initial transverse velocities U and V, to simplify the calculations, but to demonstrate the effect, are zero and, therefore, b ₂ = 0. For ions with a given

their trajectories are determined by δW / W. Let the value δW / W = -A _m . Different δW / W correspond to the trajectories of two classes. For δW / W <-A _{m, the} quantity b ₁ <0, and the ions, not returning to χ * = 0, go as φ → ∞ to -∞ in χ *. However, for δW / W> -A _{m, the} quantity b ₁ > 0, and the ions return to χ * = 0 a number of times, and as φ → ∞ they go to + ∞ in χ *. There is sure to be a value of δW / W that lies in the region

, and in which the trajectory of the ion with

passes through χ * = 0 for φ = φ ₁ . This means that ions of masses other than m ₀ will fall into the detector, and for separating ions, using only the separating capabilities of this set of electromagnetic fields is not enough.

и

Рассмотрим такую траекторию иона при каком-то, пока неизвестном δW/W=-А_k, когда траектория лежит обязательно выше, чем

Причем она касается

при каком-то φ=φ₀, то есть

Кроме того, пусть данная траектория проходит через точку

, φ=φ₁. Тогда частицы с фиксированным значением

вообще не попадут на фокусную плоскость φ=φ₁. Действительно, при δW/W<-A_k ионы гибнут на поверхности

a при δW/W>-А_k они идут выше критической траектории δW/W=-A_k и гибнут на поверхности

. Ионы с массами, большими, чем выбранная масса m, также попадают на электроды.To achieve this goal, we will interrupt the trajectories of non-target particles on the cylindrical electrodes of the analyzer (on the channel walls). Let us find the condition under which ions with masses greater than m ₀ + δm (δm> 0) hit the walls before reaching the particle detection plane φ = φ ₁ . We arrange the conductive cylindrical surfaces between which a radial electric field is created, at distances

and

Let us consider such an ion trajectory for some, as yet unknown δW / W = -A _k , when the trajectory lies necessarily higher than

And it concerns

for some φ = φ ₀ , i.e.

In addition, let this trajectory pass through a point

, φ = φ ₁ . Then particles with a fixed value

generally do not fall on the focal plane φ = φ ₁ . Indeed, for δW / W <-A _{k, the} ions die on the surface

a when δW / W> -A _k they go above the critical trajectory δW / W = -A _k and die on the surface

. Ions with masses larger than the selected mass m also fall on the electrodes.

надо определить критическую траекторию, для чего необходимо найти значения -A_k, χ_c и φ₀. Для этого есть три уравнения:So for a fixed relationship

it is necessary to determine the critical trajectory, for which it is necessary to find the values -A _k , χ _c and φ ₀ . There are three equations for this:

χ * (φ = φ ₁ ) = χ _c ;

χ * (φ = φ ₀ ) = - χ _C.

We write these equations using (21) for U = V = 0:

To solve system (24-26), we use the smallness of the parameter ^γ / _ω ; with φ ₀ << 1. Adding (24) and (26), we obtain:

Expanding in equation (25) sin (ωφ ₀ ) and sinh (γφ ₀ ) to the third order in φ ₀ , we obtain:

From equation (27), in turn, we obtain:

Substituting (28) and (29) into equation (24), we find:

The trajectories of particles with masses less than m (δm <0) will be located symmetrically with respect to the trajectories of ions with masses larger than m (δm> 0). The symmetry of the trajectories will be realized relative to the line χ * (φ) = 0. Therefore, formula (30), determining the quantity | χ _c |, sets the distance from χ * (φ) = 0 to the channel walls, on which ions with masses differing from m ₀ by an amount greater than | δm | die. As a result, mass analysis of ions in this device is also carried out in the presence of an initial energy spread.

Обозначая через S=U(ω²-2)+2V/ε и решая уравнение (21), получаем, что в плоскости детектирования при φ₁=π/ω к величине χ*(φ₁) с b₁=b₂=0 добавляется величина

Для того чтобы при наличии углового разброса у ионов исходного потока на детекторе не появлялись нецелевые частицы с массами m₀+Δm, где |Δm| существенно превышало бы |δm|, необходимо выполнение условия:Now we take into account the final initial spread in the angle for the analyzed ion flux. Consider the case when b ₂ ≠ 0, i.e.

Denoting by S = U (ω ² -2) + 2V / ε and solving equation (21), we find that in the detection plane for φ ₁ = π / ω to χ * (φ ₁ ) with b ₁ = b ₂ = 0 value is added

In order to prevent the appearance of non-target particles with masses m ₀ + Δm, where | Δm | would significantly exceed | δm |, it is necessary to fulfill the condition:

Using the fact that max | U | = max | V | = θ, where θ is the maximum angular spread of the analyzed ion flux, from (31) we obtain the condition for the permissible angular spread:

For ε = 1, the quantities γ and ω are approximately equal to 0.75 and 1.9, respectively. Then condition (32) is modified:

Thus, the claimed energy-mass analyzer provides mass diagnostics for both a specific energy and angular dispersion of the ions of the analyzed stream.

The inventive method is implemented as follows.

, аналогично работе энергоанализатора Юза-Рожанского. Движение вдоль оси Z (уход из области выходной диафрагмы; непопадание на детектор) исключается совместным действием полей E_z и В, задающих величину скорости иона, проходящего на детектор,

, так же, как работает классический фильтр Вина. Ион другой массы будет оставаться на центральной основной траектории (радиусом R), если напряженность электрического поля Е_z, при фиксированных Е₀ и В, выбрана равнойThe stream of analyzed ions with a certain set of masses with different energies enters through the input diaphragm at a point with radius R at φ = 0 into the region of the energy-mass analyzer - into the zone of action of electric fields: radial E ₀ and longitudinal E _z , magnetic field B directed along the radius. In the absence of an initial angular spread, an ion having an initial velocity V _φ0 remains on a trajectory of radius R if it has an energy W ₀ defined by the value of the radial electric field strength

, similar to the work of the energy analyzer Yuz-Rozhansky. Movement along the Z axis (moving away from the area of the output diaphragm; missing the detector) is excluded by the combined action of the fields E _z and B, which specify the velocity of the ion passing to the detector,

, just like the classic Vin filter works. An ion of a different mass will remain on the central main trajectory (radius R) if the electric field strength E _z , at fixed E ₀ and B, is chosen equal to

, будет наблюдаться пространственная фокусировка частиц (см. фиг.3) после поворота иона в анализаторе на угол

В случае

частицы сфокусируются при значении угла, равном

. В точках фокусировки ионов с

частицы с

отходят от равновесной траектории на максимальное расстояние, равное

.If the deviation of the ion mass m from the value of m _{0 is} small, as well as the initial scatter in the velocities U and V, then for certain values of δm / δW and U / V, when

, spatial focusing of particles will be observed (see Fig. 3) after the ion is rotated through an angle in the analyzer

When

particles will focus at an angle equal to

. At the focal points of ions with

particles with

move away from the equilibrium trajectory to a maximum distance equal to

.

пройдет через точку фокусировки частиц с

и в детектор будут попадать ионы и других, кроме m₀, масс. Для исключения перемешивания ионов разных масс на детекторе в энерго-масс-анализаторе по данной заявке используется, аналогично классическому фильтру скоростей Вина, прерывание траекторий нецелевых частиц (с массами, отличающимися от m₀ на величину, большую чем |δm|) на цилиндрических электродах анализатора, которые располагаются на расстоянии друг от друга, равном

В результате, масс-анализ ионов в данном устройстве осуществляется и при наличии начального разброса по энергиям.A case is possible for some value of δW / W, when the ion trajectory with

will go through the particle focal point with

and ions other than m ₀ , masses will fall into the detector. To exclude mixing of ions of different masses at the detector in the energy-mass analyzer, according to this application, interruption of the trajectories of non-target particles (with masses different from m ₀ by an amount greater than | δm |) on the analyzer’s cylindrical electrodes is used which are located at a distance from each other equal to

As a result, mass analysis of ions in this device is also carried out in the presence of an initial energy spread.

.If there is a finite initial dispersion of the flow of analyzed particles in angle, non-target particles will not get to the detector when the maximum angular spread of the analyzed ion flux θ, for example, for the case of equal radial and longitudinal electric fields, does not exceed

.

Thus, the inventive energy-mass analyzer provides mass diagnostics both in the presence of ions of the analyzed flow of energy and angular dispersion. For an ion flux of one mass, the analyzer measures the energy distribution of ions.

The inventive device operates as follows.

The analyzed ion flux is included in the inventive device — the Vin-Yuz-Rozhansky analyzer through the input diaphragm 1 (Fig. 1, 2) at a point with coordinates φ = 0, r = R. An inhomogeneous radial magnetic field B _{r of the} cylindrical Wien filter, which is created using the magnetic field creation system 2, an inhomogeneous radial electric field E _{r of the} Yuz-Rozhansky energy analyzer, which is created using two cylindrical electrodes 3, and a uniform electric field E begin to act on charged particles. _z cylindrical Wien filter produced electrode system 4. As a result, the energy-mass analysis in the outlet aperture 5 and the detector (receiver ions) 6 reach a predetermined mass and ions nergii. Figures 3 and 4 show examples of calculations of ion trajectories when changing the azimuthal velocity component (Fig. 3) and the magnitude of the initial radial and Z-component of ion velocities (Fig. 4).

The ion detector 6 is located at the turning point of the trajectory of the target ion at an angle φ = π / ω (ω, 1 / rad), on which these ions are focused, and ions of other masses move as far away from the main trajectory as possible. The cylindrical electrodes 3 of the analyzer are made with a distance between them equal to

where γ, 1 / rad is a parameter that determines the angle at which non-target ions go as far as possible from the equilibrium path and die on cylindrical electrodes; ω is a parameter that determines the angle at which the target ions are focused on the equilibrium trajectory, at which the detector is located.

Claims (2)

1. The method of analysis of charged particles by energy and mass, including energy analysis in the electric field of a cylindrical capacitor — in the Yuz-Rozhansky energy analyzer, mass analysis in crossed electric and magnetic fields of the Wien filter, characterized in that the energy and mass analysis is carried out in the combined radial electric field of the Yuz-Rozhansky energy analyzer and the radial magnetic field of the Wien filter and the longitudinal electric field of the Wien filter transverse to them, while the ion detector is placed at the turning point trajectory at an angle
φ = π / ω,
where ω is the parameter that determines the angle at which the target ions are focused on the equilibrium path, 1 / rad,
and the cylindrical electrodes of the energy analyzer Yuz-Rozhansky have a distance between them, determined by the formula

where γ is the parameter that determines the angle at which non-target ions go as far as possible from the equilibrium trajectory, 1 / rad. 2. A device for analyzing charged particles by energy and mass, comprising a Yuz-Rozhansky energy analyzer and a Wine filter, characterized in that the Wien filter is cylindrical, a Yuz-Rozhansky energy analyzer and a Wien filter so that the magnetic poles of the Wien filter cover the cylindrical electrodes of the Yuz energy analyzer Rozhansky, and the Wien filter plates that create the electric field are made in the form of flat round electrodes placed on both sides relative to the Yuz-Rozhansky energy analyzer and the magnetic system emy Wien filter, wherein the ion detector is positioned at the turning point of the trajectory at a corner
φ = π / ω,
where ω is the parameter determining the angle at which the target ions are focused on the equilibrium path, 1 / rad,
and the cylindrical electrodes of the Yuz-Rozhansky energy analyzer are made with a distance between them equal to

where γ is the parameter that determines the angle at which non-target ions go as far as possible from the equilibrium trajectory, 1 / rad.

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