CN109585244A - The Electron Beam Focusing device of high power density - Google Patents
The Electron Beam Focusing device of high power density Download PDFInfo
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- CN109585244A CN109585244A CN201811281545.9A CN201811281545A CN109585244A CN 109585244 A CN109585244 A CN 109585244A CN 201811281545 A CN201811281545 A CN 201811281545A CN 109585244 A CN109585244 A CN 109585244A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
- H01J37/10—Lenses
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/252—Tubes for spot-analysing by electron or ion beams; Microanalysers
- H01J37/256—Tubes for spot-analysing by electron or ion beams; Microanalysers using scanning beams
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
- H01J37/261—Details
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/3002—Details
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Abstract
The invention discloses a kind of Electron Beam Focusing devices of high power density, including the condenser module, auxiliary condenser module and objective lens module set gradually along the electron beam direction of the launch；The condenser module is used to form the first magnetic field, so that electron beam forms crosspoint；The auxiliary condenser module is used to form the second magnetic field, so that the motion profile of electron beam is parallel with optical axis, forms parallel beam, first magnetic field is bigger than the magnetic field strength in the second magnetic field；The objective lens module is used to form third magnetic field, makes Electron Beam Focusing to target plane.Using condenser, assist the poly-lens combination of condenser and object lens, realize the intersection-of electron beam it is parallel-focus control, to obtain the high efficiency transmitting of the high reduction magnification of electron beam system, small aberration and line.
Description
Technical field
The invention belongs to three dimensional lossless micro-observation technology fields, and in particular to a kind of Electron Beam Focusing device.
Background technique
The Electron Beam Focusing device of high power density can be used for generating corresponding ray pair using beam bombardment target
In the imaging device that sample is scanned, for example, Micro-CT scanning technology (Micro-Computed Tomography, Micro-CT)
Be it is a kind of sample is scanned using X-ray, the lossless micro-imaging technique by scan data inverting at 3-D image, can be with
In micron dimension, even sub-micrometer scale is come characteristic informations such as the internal structures, density and defect that show sample, extensively
It is general to be applied to the detection of the fields such as life science, materialogy and geology, it improves detection resolution and efficiency is Micro-CT scanning technology
Developing direction.The x-ray source that electron beam is practiced shooting is one of core component of Micro-CT scanning, detection resolution and efficiency and radiographic source
Focal spot size, power density it is directly related.
Electron beam target practice x-ray source generallys use poly-lens focusing system, is known as object apart from the closer magnetic lenses of target plane
Mirror is condenser apart from the farther away magnetic lenses of target surface.Incident beam generates X-ray after acting on target at target surface,
Middle incident beam beam spot determines that the focal spot size of x-ray source, line and acceleration voltage determine the power of X-ray.Adding
Periodically, generation x-ray source power density is also higher after the beam bombardment target plane that line is bigger, beam spot is smaller for fast voltage one,
The detection efficiency and resolution ratio of its X-ray micro imaging system are also higher.However, in magnetic lenses focusing system, by electronics
Lagrange-Helmholtz's relationship in optical theory is it is found that linear narrowing multiplying power and angular magnification are reciprocal each other.If simple
It being reduced using multi-stage lens and obtains small electron beam spot, angle enlargement ratio will become larger accordingly, and in actual lens system
In to guarantee paraxial relationship, the aperture of the diaphragm is typically small in electron beam channel, and electron beam cannot effectively pass through big angle times magnification
The focusing system of rate, so that the electron beam line for making to bombard on target surface is reduced；Therefore, common poly-lens focusing system is difficult
Guarantee that bombardment is provided simultaneously with big line and small beam spot to the electron beam on target surface, and then affects the focal spot ruler of produced X-ray
Very little and power density.
Electron beam target practice x-ray source focusing system reequip mostly or referring to electron microscope magnetic lenses, when target surface
Electron beam spot hour, line is also smaller, and the x-ray power density of generation is not also high, is difficult to obtain the clear of high-resolution ability
Clear picture.
Summary of the invention
The present invention, it is difficult to ensure that aiming at the problem that combining big line and the small beam spot on target surface, is proposed poly-lens system
A kind of poly-lens Compound focusing system device for the high pass efficiency can be realized high reduction magnification, small aberration and line, tool
Body refers to a kind of Electron Beam Focusing device of high power density.
The Electron Beam Focusing device of high power density, including set gradually along the electron beam direction of the launch condenser module,
Assist condenser module and objective lens module；
Condenser module is used to form the first magnetic field, so that electron beam forms crosspoint；Condenser module is assisted to be used for shape
At the second magnetic field, so that the motion profile of electron beam is parallel with optical axis, parallel beam, magnetic field of first magnetic field than the second magnetic field are formed
Intensity is big；Objective lens module is used to form third magnetic field, makes Electron Beam Focusing to target plane.
Optionally, the Electron Beam Focusing device of high power density further includes electron beam channel pipe, and electron beam channel pipe is successively
Across condenser module, auxiliary condenser module and objective lens module.
Optionally, condenser module further includes the first upper magnet yoke being fixedly connected and the first lower yoke, and auxiliary condenser is also
Including the second upper magnet yoke being fixedly connected and the second lower yoke；First lower yoke and the second upper magnet yoke are integrally formed, hereinafter,
First lower yoke and the integrally formed magnetic yoke of the second upper magnet yoke are referred to as condenser-auxiliary condenser magnetic yoke；By condenser module
It is module-integrated with auxiliary condenser, material is not only saved, the centering adjustment of system is also facilitated.
Optionally, there is first annular chamber between the first upper magnet yoke and the first lower yoke；Second upper magnet yoke and the second lower magnetic
There is the second annular chamber between yoke；Condenser module includes the first magnetic field formation component, and setting is arranged first annular intracavitary
On electron beam channel pipe, for generating the first magnetic field；Assisting condenser includes the second magnetic field formation component, is arranged in the second ring
Shape is intracavitary, and is set on electron beam channel pipe, for generating the second magnetic field；First magnetic field formation component and the second magnetic field generate
Component is mutually independent magnetic field formation component.
Optionally, objective lens module includes third magnetic field formation component, for generating third magnetic field, third magnetic field generation group
Part, the first magnetic field formation component and the second magnetic field formation component are respectively mutually independent magnetic field formation component.
Optionally, the first magnetic field formation component includes: the first pole shoe member, is set on electron beam channel pipe；First Line
Coil assembly, setting is in the first pole shoe member periphery；Second magnetic field formation component includes: the second pole shoe member, is set in electron beam
In tube channel；Second coil block, setting is in the second pole shoe member periphery；First coil component and the second coil block all can be only
The vertical respective coil block exciting current of adjustment, so as to adjust the intensity in the first magnetic field and the second magnetic field.
Optionally, optically focused mirror assembly further includes condenser, and the horizontal center line and electron beam of the first pole shoe member is arranged in
The central axis intersection position of tube channel；Auxiliary optically focused mirror assembly further includes auxiliary condenser, and the second pole shoe member is arranged in
The central axis intersection position of horizontal center line and electron beam channel pipe.
Optionally, Electron Beam Focusing device further includes transitional module, is fixed at assisted focused mirror module and object lens mould
Between block.
Optionally, Electron Beam Focusing device further includes lens isis seat, is fixed at the lower end of objective lens module, electron beam
Tube channel is fixedly connected on lens isis seat.
The present invention has the advantages that
(1) the Electron Beam Focusing device of a kind of high power density, using condenser, the poly-lens of auxiliary condenser and object lens
Combination, condenser module are used to form the first magnetic field, so that electron beam strong-focusing, forms crosspoint, realize electron beam
Reduction magnification needed for system, auxiliary condenser module is used to form second magnetic field weak compared to the first magnetic field, so that electronics
Beam weak focus keeps the motion profile of electron beam parallel with optical axis, forms parallel beam, reduces the mutually exclusive power of electronics interfascicular, from
And beam divergence angle is made to become smaller, increase the electron beam in electron beam channel pipe, realizes that the small aberration of system and the high of line pass
Efficiency is passed, realizes that big line, objective lens module are used to form third magnetic field, makes Electron Beam Focusing to target plane, obtain small electronics
Beam beam spot, beam crossover-is parallel-mode that focuses, microbeam spot is realized while ensure that line.
(2) the Electron Beam Focusing device of a kind of high power density, objective lens module, condenser module and auxiliary condenser module
Respective coil block exciting current can be adjusted, independently all so as to adjust objective lens module, condenser module and auxiliary condenser mould
The magnetic field strength of block.
(3) the Electron Beam Focusing device of a kind of high power density, condenser module and auxiliary condenser module are saturating by two
Mirror integration, not only saves material, also facilitates the centering adjustment of system.
Detailed description of the invention
It, below will be to specific in order to illustrate more clearly of the specific embodiment of the invention or technical solution in the prior art
Embodiment or attached drawing needed to be used in the description of the prior art be briefly described, it should be apparent that, it is described below
Attached drawing is some embodiments of the present invention, for those of ordinary skill in the art, before not making the creative labor
It puts, is also possible to obtain other drawings based on these drawings.
Fig. 1 shows the electronics light path schematic diagram of the Electron Beam Focusing device of the high power density of the present embodiment；
Fig. 2 (a) show the present embodiment beam crossover-it is parallel-schematic diagram of focusing mode work, (b) show
Beam crossover without auxiliary condenser-focusing mode work schematic diagram；
Fig. 3 shows the overall structure figure of the Electron Beam Focusing device of the present embodiment；
Fig. 4 shows the condenser module of the present embodiment and the structural schematic diagram of auxiliary condenser module；
Fig. 5 shows the structural schematic diagram of the objective lens module of the present embodiment；
Wherein appended drawing reference are as follows:
10- electron gun；20- condenser module；30- assists condenser module；40- objective lens module；50- target；60- object lens
Diaphragm module；The first upper magnet yoke of 101-；102- condenser-auxiliary condenser magnetic yoke；The second lower yoke of 103-；The first pole shoe of 104-
Component；Pole shoe on 1041- condenser；Pole shoe under 1042- condenser；1043- condenser pole shoe magnetism-isolating loop；1044- condenser position
It sets；105- first coil component；1051- condenser coil；1052- condenser coil rack；106- condenser sealing ring；107-
Second pole shoe member；1071- assists pole shoe on condenser；1072- assists pole shoe under condenser；1073- assists condenser pole shoe
Magnetism-isolating loop；1074- assists condenser position；The second coil block of 108-；1081- assists condenser coil；1082- assists optically focused
Mirror coil rack；109- assists condenser sealing ring；201- transition root module；202- object lens upper module；203- object lens lower module；
204- objective lens coil component；2041- objective lens coil；2042- objective lens coil skeleton；205- object lens position；501- electron beam channel
Pipe；601- lens isis seat.
Specific embodiment
Technical solution of the present invention is clearly and completely described below in conjunction with attached drawing, it is clear that described implementation
Example is a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiment of the present invention, ordinary skill people
Member's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
As shown in Figure 1, the embodiment of the invention provides a kind of Electron Beam Focusing devices, comprising: along the electron beam direction of the launch
Condenser module 20, auxiliary condenser module 30, objective lens module 40 and the lens isis module 60 set gradually；
Condenser module 20 is used to form the first magnetic field, so that electron beam forms crosspoint；
Auxiliary condenser module 30 is used to form the second magnetic field, so that the motion profile of electron beam is parallel with optical axis, is formed
Parallel beam, first magnetic field are bigger than the magnetic field strength in the second magnetic field；
Objective lens module 40 is used to form third magnetic field, and electron beam is made to focus on target plane by lens isis module 60.
10 launching electronics beam of electron gun passes sequentially through condenser module 20, auxiliary condenser module 30,40 and of objective lens module
Lens isis module 60, as shown in Fig. 2 (a), condenser module 20 is used to form the first magnetic field, so that electron beam strong-focusing, shape
At crosspoint, reduction magnification needed for making electron beam realization system, auxiliary condenser module 30 is used to form compared to the first magnetic
The second weak magnetic field of field forms parallel beam, makes electricity so that electron beam weak focus, keeps the motion profile of electron beam parallel with optical axis
Mutually exclusive power reduces between beamlet, so that beam divergence angle be made to become smaller, realizes the small aberration of system and the high pass effect of line
Rate realizes that big line, objective lens module 40 are used to form third magnetic field, and electron beam is made to focus on target by lens isis module 60
50 planes obtain small electron beam spot, to realize microbeam spot while guaranteeing line, the electron beam of microbeam spot passes through bombardment target
Material 50 generates X-ray beam.If without the second magnetic field that auxiliary condenser 30 is formed, as shown in Fig. 2 (b), under same minification,
Beam divergence angle is too big when electron beam forms crosspoint by 20 electron beam of condenser module, has been more than lens isis module 60
Acceptance angle, reduce focusing system to the transmission efficiency of electron beam line, reduce the line for reaching target surface.
Electron Beam Focusing device generally cylindrical structure, as shown in figure 3, including electron beam channel pipe 501, condenser mould
Block 20, auxiliary condenser module 30, transition root module 201, objective lens module 40 and lens isis seat 601.
In order to avoid electronics flies around in entire Electron Beam Focusing device, using electron beam channel pipe 501 and object lens
Electronics is limited in the paraxial region of system by diaphragm seat 601.
Electron beam channel pipe 501 is integrally located on the central axis of Electron Beam Focusing device, using duralumin or copper product system
At hollow pipe, 501 upper end of electron beam channel pipe connect with electron gun 10, sequentially passes through condenser module 20, auxiliary condenser
After module 30, transition root module 201, objective lens module 40, lower end is connect with lens isis seat 601.Condenser module 20, auxiliary are poly-
Connected realized by screw between light microscopic module 30, transition root module 201, objective lens module 40 and lens isis seat 601 connects
It connects.
Transition root module 201 is the cylindrical body of inner hollow, the central axes of cylindrical body and the axis of electron beam channel pipe 501
Line is identical.
Condenser module 20 and auxiliary condenser module 30 are as shown in figure 4, include the first upper magnet yoke 101, condenser-auxiliary
Condenser magnetic yoke 102, the second lower yoke 103 and the first pole shoe member 104, first coil component 105, condenser sealing ring 106
And second pole shoe member 107, the second coil block 108, auxiliary condenser sealing ring 109；
Condenser-auxiliary condenser magnetic yoke 102 upper and lower end face is all provided with annular groove；
The lower end surface of first upper magnet yoke 101 is provided with annular groove, with condenser-auxiliary condenser magnetic yoke 102 upper surface
Make-up fixed placement, and sealed off with condenser sealing ring 106, form first annular chamber, the first upper magnet yoke 101, condenser-
Assist the central axes of condenser magnetic yoke 102 identical as the central axes of electron beam channel pipe 501；First magnetic field formation component includes the
One pole shoe member 104 and first coil component 105, the first pole shoe member 104 is including under pole shoe 1041 and condenser on condenser
Pole shoe 1042 is assembled integrally by pole shoe magnetism-isolating loop 1043, identical as the central axes of electron beam channel pipe 501；First pole shoe
The horizontal center line of component 104 and the central axis upright of electron beam channel pipe 501, and intersection position is condenser position
1044；First coil component 105 is circular rings, including condenser coil 1051 and condenser skeleton 1052, is pacified by bobbin
In the first annular chamber that the first upper magnet yoke 101 is formed with condenser-auxiliary condenser magnetic yoke 102, and in the first pole shoe group
The periphery of part 104；First magnetic field formation component is used to form the first magnetic field, so that electron beam strong-focusing, forms crosspoint, make electricity
Reduction magnification needed for beamlet realization system；
The upper surface of second lower yoke 103 is provided with annular groove, with condenser-auxiliary condenser magnetic yoke 102 lower end surface
Make-up fixed placement, and sealed off with auxiliary condenser sealing ring 109, the second annular chamber of formation, in the second lower yoke 103
Axis is identical as the central axes of electron beam channel pipe 501；First magnetic field formation component includes the second pole shoe member 107 and the second line
Coil assembly 108, the second pole shoe member 107 include pole shoe 1071 and pole shoe 1072 under auxiliary condenser on auxiliary condenser, are passed through
Pole shoe magnetism-isolating loop 1073 assembles integrally, identical as the central axes of electron beam channel pipe 501；The level of second pole shoe member 107
The central axis upright of center line and electron beam channel pipe 501, and intersection position is auxiliary condenser position 1074；Second coil
Component 108 is circular rings, including auxiliary condenser coil 1081 and auxiliary condenser skeleton 1082, is mounted on the by bobbin
In the second annular chamber that two lower yokes 103 are formed with condenser-auxiliary condenser magnetic yoke 102, and in the second pole shoe member 107
Periphery；Second magnetic field formation component is used to form the second magnetic field, so that electron beam weak focus, makes the motion profile of electron beam with light
Axis is parallel, forms parallel beam, reduces the mutually exclusive power of electronics interfascicular, so that beam divergence angle be made to become smaller, increases electron beam
Electron beam in tube channel 501 realizes the small aberration of system and the high pass efficiency of line, realizes big line；
First magnetic field formation component and the second magnetic field formation component can be mutually independent magnetic field formation component, all can be only
The vertical respective coil block exciting current of adjustment, so as to adjust the magnetic field strength in the first magnetic field and the second magnetic field.
Objective lens module 40 is as shown in figure 5, objective lens module 40 includes object lens upper module 202, object lens lower module 203 and objective line
Coil assembly 204；Object lens upper module 202 is in " mountain " font, including pole shoe on object lens upper magnet yoke and object lens, by one block of pure iron material
Or spheroidal graphite cast-iron is process；Object lens lower module 203 uses the cylindrical body of inner hollow, including pole under object lens lower yoke and object lens
Boots are process by one block of pure iron material or spheroidal graphite cast-iron；Third magnetic field formation component includes pole shoe on object lens, pole shoe under object lens
With objective lens coil component 204, third magnetic field formation component is used to form third magnetic field, makes Electron Beam Focusing to 50 plane of target,
Obtain small electron beam spot.
203 make-up fixed placement of object lens upper module 202 and object lens lower module, hollow internal placement objective lens coil component 204；
The axial symmetry center of object lens upper module 202 and object lens lower module 203 is identical as the central axis of electron beam channel pipe 501, while
Axial symmetry is provided with channel on center, so that electron beam passes through；
Objective lens coil component 204 is circular ring shape, 203 top of object lens lower module is placed in, by adjusting objective lens coil component
204 exciting currents, so as to adjust the magnetic field strength in third magnetic field；The horizontal direction of object lens upper module 202 and object lens lower module 203
Gap is formed, the center in gap and the crosspoint of axis are object lens positions 205.
40 lower end of objective lens module is socketed lens isis seat 601, the whole rounded ring structure of lens isis seat, circle ring center
Hole is lens isis hole.
It is described in detail below with reference to the parameter of the Electron Beam Focusing device of Fig. 1-5 pairs of high power densities, specifically, electric
The parameter of beamlet focusing device may include: initial parameter and performance indicator, according to the knot of the objective lens module of initial parameter setting
The position of structure parameter and electric parameter and condenser module and auxiliary condenser module, structurally and electrically parameter, specific:
The initial parameter of the Electron Beam Focusing device of high power density includes the parameter of electron source parameter and target；
Electron source parameter include beam energy, beam energy divergence, emission lamp point position and diameter, lamp tip temperature,
Theoretical brightness, spatial distribution, intersects spot diameter and the angle of emergence at source line；The parameter of target includes type and the position of target, commonly
There are two types of targets: reflecting target and transmission target, and transmission-type high geometry amplification factor easy to accomplish is usually used in high resolution detection；And it is anti-
The formula of penetrating has the characteristics that powerful, but there are heel effects, and resolution ratio is smaller, and the present invention illustrates by taking transmission target as an example.
Select 160kV lanthanum hexaboride as the electronics of the micro- focal spot x-ray source focusing device of electron beam target practice high power density
Emission source, parameter are as shown in table 1.
Table 1 is the parameter of electron emission source of the present invention
The parameter of target is shown in Table 2.
Table 2 is the parameter of target of the present invention
| The type of target | Transmission target |
| The position of target surface | Closely pole shoe lower surface under object lens |
2) performance indicator of Electron Beam Focusing device is the line and beam spot diameter, of electron beam on target surface, and parameter is listed in table 3；
Line at target surface is expressed as
In formula, β is the brightness of electron gun, and m is the reduction magnification of system, 0 < m < 1, d0Intersect spot diameter, α for electron source
For the angular aperture of electron beam；
At target surface lectron beam spot diameter can approximate representation be
In formula,It is spherical aberration disperse spot diameter,It is color difference disperse spot diameter, CsAnd CcRespectively
For the coefficient of spherical aberration and chromatic aberration coefficient of object lens；E is the energy of electronics, and Δ E is the energy spread of electronics.
Under given electron source parameter, the focal spot of high power density is obtained, then needs big line, small beam spot, but big beam
Stream necessarily brings big target surface incidence angle, and beam spot also can be big, therefore big line and small beam spot contradiction each other, need to comprehensively consider；Due to
Voltage of the present invention is relatively high, it is possible to ignore color difference, and in order to obtain microbeam spot, the object lens of low coefficient of spherical aberration need to be designed, together
When comprehensively consider incident beam half-angle at reduction magnification and target surface.
Table 3 is the line and diameter of electron beam on target surface of the present invention
| Electron beam line | ≥50μA |
| Beam spot diameter, | ≤1μm |
The structural parameters and electric parameter of objective lens module are set according to primary condition, specific:
1), the position and structure parameter of objective lens module is set；
The structural parameters of objective lens module include the structure ginseng of lower yoke on the structural parameters and object lens of pole shoe above and below object lens
Number；
The structural parameters of object lens pole shoe up and down include: object lens pole shoe material, the operating distance of object lens, pole shoe on object lens up and down
Aperture D1, under object lens pole shoe aperture D2 and upper and lower pole shoe gap S；
The structural parameters of lower yoke include: object lens magnetic yoke size, pole shoe outer diameter on object lens, angle, pole on object lens on object lens
Under boots thickness, object lens under pole shoe outer diameter, angle, object lens pole shoe thickness and objective line coil geomery；
The position of object lens is the center in object lens or more pole shoe gap；
According to the image-forming condition of electron source parameter and the parameter designing objective lens module of target, the property of focusing system device is obtained
The structure design of energy index, objective lens module should meet: bigger according to focal length more long reach, the aberration of focusing system device is got over
Greatly, and the principle that becomes smaller of the scaling of focusing system device should be use up to reduce the lectron beam spot diameter at target surface incidence
Amount shortens the operating distance that the distance between pole shoe lower end surface and target surface under object lens are object lens, in conjunction with practical focusing system device
Assembly, preferably 0mm；In order to limit stray electron, the diameter range of the aperture among lens isis seat is 0.2mm~1.5mm, excellent
It is selected as 1mm.The aperture D2 of pole shoe is bigger under the aperture D1 and object lens of pole shoe on object lens, more readily satisfies optical axis paraxial condition, object
Mirror stability is higher and aberration is smaller, but the magnetic yoke of object lens is easily saturated, and after comprehensively considering, the range of aperture D1 and D2 are 4mm
~30mm, preferably 12mm.With the reduction of the gap S of pole shoe under pole shoe on object lens and object lens, aberration becomes smaller, but too small and appearance
It is also easy to produce saturation, the range of gap S is 1mm~20mm, preferably 5.5mm.Meanwhile in order to avoid magnetic circuit saturation, also need to optimize
Magnetic yoke length, thickness etc., important parameter is shown in Table 4.
Table 4 is the key parameter of objective lens module of the present invention
| Pole shoe material | Electrical pure iron DT4C |
| The operating distance of object lens | 0mm |
| Pole shoe aperture D1 on object lens | 12mm |
| Pole shoe aperture D2 under object lens | 12mm |
| Pole shoe gap S above and below object lens | 5.5mm |
| Pole shoe thickness under object lens | 2.865mm |
| The excitation of objective lens coil component | 4297A-t |
| The position of object lens | 294.5mm |
| Lens isis bore dia | 1mm |
2), the electric parameter of objective lens module is set；
The electric parameter of object lens is the excitation A-t of objective lens coil module.According to the design of front, in conjunction with the knot of objective lens module
After structure parameter model numerical value calculates the spatial distribution for obtaining magnetic objective, electron source, object lens and target are placed in the object formed together
Mirror focusing system calculates motion profile of the electron beam under magnetic fields and adjusts the excitation of object lens according to the operating distance of selection
Electron Beam Focusing is controlled on target plane.By calculating, when object lens are actuated to 4297A-t, line is 80 μ A on target, and beam spot is
1μm。
Condenser module is set and assists the position of condenser module, structurally and electrically parameter, contracting needed for realization system
Intersection-parallel model of small multiplying power and electron beam, specific:
1), condenser module is set and assists the position and structure parameter of condenser module, diminution needed for realization system
Multiplying power；
The structural parameters of condenser module and auxiliary condenser module include the knot of about the first pole shoe, about the second pole shoe
The structural parameters of structure parameter and the first upper magnet yoke, condenser-auxiliary condenser magnetic yoke, the second lower yoke；
The structural parameters of about first pole shoe, material including about the first pole shoe, the aperture D11 of pole shoe, on first
The aperture D21 of pole shoe and about the first pole shoe gap S1 once；
The structural parameters of about second pole shoe, material including about the second pole shoe, the aperture D12 of pole shoe, on second
The aperture D22 and about the second pole shoe gap S2 of two lower pole shoes；
First upper magnet yoke, condenser-auxiliary condenser magnetic yoke, the second lower yoke structural parameters include each yoke material,
Every magnetic assembly parts, the structure size of first coil, the structure size of the second coil；
Condenser and auxiliary condenser position are respectively the center and about the second pole shoe gap in about the first pole shoe gap
Center；
Condenser module and auxiliary condenser module important parameter are listed in table 5.
Table 5 is condenser of the present invention-auxiliary condenser module important parameter
| Condenser pole shoe, yoke material | Electrical pure iron DT4C |
| Pole shoe aperture D11 on first | 12mm |
| First lower pole shoe aperture D21 | 12mm |
| About first pole shoe gap S1 | 6mm |
| Condenser position | 80mm |
| The excitation of first coil component | 2554A-t |
| Second pole shoe, yoke material | Electrical pure iron DT4C |
| Pole shoe aperture D12 on second | 12mm |
| Second lower pole shoe aperture D22 | 12mm |
| About second pole shoe gap S2 | 6mm |
| Assist condenser position | 152mm |
| The excitation of second coil block | 1264A-t |
| Every magnetic assembly parts | Copper/duralumin, hard alumin ium alloy |
2), optimize condenser module and assist the electric parameter of condenser module, realize the parallel mould of the intersection-of electron beam
Formula；
The electric parameter of condenser module is the excitation A-t of first coil component, assists the electric parameter of condenser module
For the excitation A-t of the second coil block；By theory it is found that system can be improved in the object distance increase of condenser and auxiliary condenser
Zoom ratio, but in order to guarantee line on target, object distance should not be too large.According to condenser module parameter, second-order finite element meter is utilized
The first magnetic field is calculated, control first coil excitation makes it form crosspoint in place, later according to auxiliary condenser module
Parameter calculates the second magnetic field using second-order finite element, controls the second coil stimulating, makes electron beam by moving behind the second magnetic field
Track is parallel with optical axis, forms parallel beam.
Condenser module, auxiliary condenser module combined with objective lens module the intersection-to be formed it is parallel-focusing focusing system
System, as shown in Figs. 1-5, in conjunction with electron source parameter, the position of each lens, excitation etc., by numerical simulation calculation, finally exists
It is 80 μ A that line is obtained under the acceleration voltage of 160kV, and beam spot is 0.9 μm, and power density is better than 1W/ μm2Microbeam beam spot electronic.
Although the embodiments of the invention are described in conjunction with the attached drawings, but those skilled in the art can not depart from this hair
Various modifications and variations can be made in the case where bright spirit and scope, and such modifications and variations are each fallen within by appended claims
Within limited range.
Claims (10)
1. a kind of Electron Beam Focusing device of high power density characterized by comprising
Condenser module, auxiliary condenser module and the objective lens module set gradually along the electron beam direction of the launch；
The condenser module is used to form the first magnetic field, so that electron beam forms crosspoint；
The auxiliary condenser module is used to form the second magnetic field, so that the motion profile of electron beam is parallel with optical axis, is formed flat
Row beam, first magnetic field are bigger than the magnetic field strength in the second magnetic field；
The objective lens module is used to form third magnetic field, makes Electron Beam Focusing to target plane.
2. focusing device according to claim 1, which is characterized in that further include:
Electron beam channel pipe sequentially passes through the condenser module, the auxiliary condenser module and the objective lens module.
3. focusing device according to claim 2, which is characterized in that the condenser module further includes be fixedly connected
One upper magnet yoke, the first lower yoke, the auxiliary condenser further includes the second upper magnet yoke being fixedly connected, the second lower yoke；
First lower yoke and second upper magnet yoke are integrally formed.
4. focusing device according to claim 3, which is characterized in that
There is first annular chamber between first upper magnet yoke and first lower yoke；
There is the second annular chamber between second upper magnet yoke and second lower yoke；
The condenser module includes the first magnetic field formation component, and setting is set in the electricity described first annular intracavitary
In beamlet tube channel；
The auxiliary condenser includes the second magnetic field formation component, is arranged in second annular chamber, and be set in the electricity
In beamlet tube channel；
First magnetic field formation component and the second magnetic field formation component are mutually independent magnetic field formation component.
5. focusing device according to claim 4, which is characterized in that the objective lens module includes:
Third magnetic field formation component, for generating third magnetic field, third magnetic field formation component, the first magnetic field generation group
Part and the second magnetic field formation component are respectively mutually independent magnetic field formation component.
6. focusing device according to claim 4, which is characterized in that
First magnetic field formation component includes:
First pole shoe member is set on the electron beam channel pipe；
First coil component, setting is in the first pole shoe member periphery；
Second magnetic field formation component includes:
Second pole shoe member is set on the electron beam channel pipe；
Second coil block, setting is in the second pole shoe member periphery.
7. focusing device according to claim 6, which is characterized in that
The optically focused mirror assembly further includes condenser, and the horizontal center line and electron beam channel of first pole shoe member is arranged in
The central axis intersection position of pipe；
The auxiliary optically focused mirror assembly further includes auxiliary condenser, and the horizontal center line and electricity of second pole shoe member is arranged in
The central axis intersection position of beamlet tube channel.
8. focusing device described in -6 any one according to claim 1, which is characterized in that further include:
Transitional module is fixed between the assisted focused mirror module and the objective lens module.
9. focusing device described in -6 any one according to claim 1, which is characterized in that further include:
Lens isis seat, is fixed at the lower end of the objective lens module, and the electron beam channel pipe is fixedly connected on the object
On mirror diaphragm seat.
10. a kind of imaging device characterized by comprising
Electron beam launcher is used for launching electronics beam；
The Electron Beam Focusing device of high power density as described in any one of claims 1-9；
Imaging device, for utilizing the Electron Beam Focusing device treated electron beam imaging.
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| CN201811281545.9A CN109585244B (en) | 2018-10-23 | 2018-10-23 | High power density electron beam focusing device |
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| CN111413727A (en) * | 2020-04-15 | 2020-07-14 | 中国科学院电工研究所 | Electron beam divergence angle measuring device and preparation method and measuring method thereof |
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