Thermal ionization ion source device

Abstract

The application discloses a thermal ionization ion source device. It comprises an evaporation belt, an ionization belt parallel to the evaporation belt, and an ion output baffle, an extraction electrode, a split focusing lens, a cylindrical focusing lens, a vertical focusing lens, a collimator and an output lens arranged in sequence along an ion transmission path. The ion output baffle and the extraction electrode are both provided with apertures, the split focusing lens is provided with symmetrical arc-shaped electrode gaps, the cylindrical focusing lens is provided with a hollow inner cavity, the vertical focusing lens is provided with a multi-layer electrode plate structure, the collimator comprises a grid-shaped electrode sheet, and the output lens comprises parallel electrode plates. The application effectively improves the focusing precision of the ion beam and the overall transmission efficiency by means of the optical structure and arrangement of the multi-stage electrostatic lens, and gradually filters, focuses, decouples and controls the ion beam at different transmission stages.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry analysis technology, specifically to a thermal ionization ion source device. Background Technology

[0002] Thermal ionization sources are one of the core components in the field of mass spectrometry. They utilize high-melting-point media such as metal filaments to ionize sample atoms at high temperatures, and are widely used in high-precision isotope measurements. Existing techniques typically employ dual-band or multi-band structures to control the evaporation and ionization temperatures of the sample.

[0003] However, the structural design of traditional thermal ionization sources relies heavily on empirical formulas and experimental trial and error, lacking systematic theoretical guidance on electric field distribution, thermal field distribution, and ion optical transmission characteristics. This results in significant electric field distortion and thermal field inhomogeneity within the ion source, leading to large initial energy dispersion of ions and asymmetric emission beam spots, which restricts the transmission efficiency and analytical sensitivity of subsequent mass analyzers.

[0004] The existing thermal ionization ion sources suffer from poor ion beam focusing and low transmission efficiency. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a thermal ionization ion source device to solve the technical problems of poor ion beam focusing effect and low transmission efficiency in the existing thermal ionization ion source.

[0006] To achieve the above-mentioned technical objectives, this application adopts the following technical solution: This application provides a thermal ionization source device, comprising: Evaporation zone; The ionization zone is arranged parallel to the evaporation zone; An ion output baffle with pores is provided and is located behind the evaporation zone and the ionization zone. An extraction electrode is provided, and the extraction electrode is located behind the ion output baffle. A split focusing lens has a symmetrical arc-shaped electrode gap, and the split focusing lens is disposed behind the lead-out electrode; A tubular focusing lens having a hollow tubular inner cavity, the tubular focusing lens being disposed behind the split focusing lens; A vertical focusing lens having a multi-layer electrode structure, wherein the vertical focusing lens is disposed behind the cylindrical focusing lens; A collimator, including a grid-like electrode sheet, is disposed behind the vertical focusing lens; An output lens includes multiple parallel electrode plates, and the output lens is disposed behind the collimator; The evaporation zone, ionization zone, ion output baffle, lead-out electrode, split focusing lens, cylindrical focusing lens, vertical focusing lens, collimator and output lens are arranged sequentially along the ion transport path.

[0007] In some embodiments of this application, the evaporation band and the ionization band are made of high-melting-point metal materials. The width of the evaporation band and the ionization band are both a first preset width, and the length is both a first preset length. The evaporation band and the ionization band are arranged in parallel, forming a gap of a first preset slit width between them. The rear of the evaporation band and the ionization band is a first preset distance from the ion output baffle.

[0008] In some embodiments of this application, the ion output baffle includes a baffle body and a driving mechanism, the driving mechanism being connected to the baffle body, the baffle body being a high-temperature resistant metal plate; a first central aperture is provided on the ion output baffle, the width of the first central aperture being a second preset width, the length being a second preset length, the extending direction of the first central aperture being parallel to the gap between the evaporation zone and the ionization zone, and the ion output baffle being a second preset distance from the lead-out electrode; It also includes a power supply module, which is electrically connected to the ion output baffle and the lead-out electrode respectively. The voltage applied by the power supply module to the ion output baffle and the lead-out electrode is configured such that the potential distribution in the passive region between them satisfies the Laplace equation to achieve field equilibrium conditions.

[0009] In some embodiments of this application, the lead-out electrode is provided with a second central aperture, the width of the second central aperture is a third preset width, the length is a third preset length, the geometric center of the second central aperture coincides with the geometric center of the lead-out electrode and is parallel to the aperture on the ion output baffle, and the lead-out electrode is a third preset distance away from the separate focusing lens.

[0010] In some embodiments of this application, the split focusing lens includes two symmetrically arranged arc-shaped electrode plates, an ion channel is formed between the two arc-shaped electrode plates, the curvature of the arc-shaped electrode plates is a preset curvature, and the closest distance between the two arc-shaped electrode plates is a fourth preset distance; The lead-out electrode and the separate focusing lens constitute an electrostatic immersion lens. They are respectively connected to different DC voltage output terminals, so that the electric field formed between them satisfies the horizontal electrostatic lens focusing condition including the ion equivalent voltage parameter.

[0011] In some embodiments of this application, the cylindrical focusing lens is a cylindrical electrode structure, and the cylindrical electrode has an inner cavity that runs through the ion transport path, the inner diameter of which is a first preset diameter.

[0012] In some embodiments of this application, the vertical focusing lens includes three electrode plates arranged sequentially along the ion transport path, with a fifth preset distance between adjacent electrode plates. The center plate of the three electrode plates is a pair of semi-circular electrodes arranged vertically opposite each other. The planes on which the pair of semi-circular electrodes are located are parallel to each other and are in the same vertical cross-section. The diameter of the semi-circular electrodes is a second preset diameter. There is a gap between the electrode plates to allow ions to pass through, and the width of the gap is a fourth preset width. The cylindrical focusing lens and the vertical focusing lens work together, and the two are connected to independent power supplies to form an electric field gradient, so as to achieve independent focusing and decoupling of the ion beam in the horizontal and vertical directions, so that the ion trajectory satisfies the linear equation relationship between off-axis distance and equivalent focal length under the paraxial approximation condition.

[0013] In some embodiments of this application, the collimator includes a plurality of parallel grid-shaped electrode sheets, which are arranged at equal intervals along the ion transport path. Each grid-shaped electrode sheet has a plurality of uniformly distributed edge grid holes. A cylindrical gap is formed in the central region of the collimator, and the diameter of the cylindrical gap is a third preset diameter.

[0014] In some embodiments of this application, the output lens includes three output electrode plates arranged in parallel along the ion transport path, with a sixth preset distance between adjacent output electrode plates. Each output electrode plate is composed of two rectangular electrode plates joined together, with a gap between the two rectangular electrode plates. The pore width of the gap is a fifth preset width.

[0015] In some embodiments of this application, the ion output baffle, lead-out electrode, split focusing lens, cylindrical focusing lens, vertical focusing lens, collimator and output lens are each provided with an independently adjustable DC voltage input terminal.

[0016] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include: By utilizing the structural configuration and positional synergy of a multi-stage electrostatic lens system, the ion beams of the pre-stage, intermediate, and post-stages can be decoupled and controlled, effectively improving the focusing accuracy and transmission efficiency of the ion beams and enhancing the overall signal-to-noise ratio of the ion source system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the embodiments will be briefly described below: Figure 1 This is a schematic diagram of the thermal ionization source device in the embodiments of this application. Figure 2 for Figure 1 A top-down view; Figure 3 for Figure 1 The left view; Figure 4 for Figure 1 A cross-sectional view along the axial direction; Figure 5 This is a schematic diagram of a split focusing lens. Figure 6 This is a schematic diagram of the structure of a tubular focusing lens; Figure 7 This is a schematic diagram of the structure of a vertical focusing lens; Figure 8 This is a schematic diagram of the collimator structure; Figure 9 This is a schematic diagram of the output lens structure; Figure 10 To set the voltage diagram for each plate; Figure 11 To set the initial ion values; Figure 12 The simulated ion flight trajectory diagram; Figure 13 This is a flowchart of ion beam formation and multi-level optical control.

[0018] Figure label: 1-Evaporation zone, 2-Ionization zone, 3-Ion output baffle, 4-Extraction electrode, 5-Separated focusing lens, 6-Tube focusing lens, 7-Vertical focusing lens, 701-Electrode plate, 702-Electrode plate, 703-Electrode plate, 8-Collimator, 9-Output lens, 901-Electrode plate, 902-Electrode plate, 903-Electrode plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] Those skilled in the art will understand that, in this specification, the term "comprising" is an open-ended expression, meaning that the stated feature is present but other features are excluded. Directional terms such as "upper," "lower," "left," and "right" refer to exemplary directions based on the accompanying drawings. Features specified as "first" or "second" implicitly include one or more of that feature. Singular expressions can also be used in plural forms. "Multiple" means two or more. The terms "installed," "connected," and "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection via an intermediate medium, and it can be a connection within two components. Furthermore, "linked" can include wireless connections.

[0021] Combination Figures 1 to 4 As shown, this application provides a thermal ionization source device, which includes an evaporation zone 1, an ionization zone 2, an ion output baffle 3, an extraction electrode 4, a split focusing lens 5, a cylindrical focusing lens 6, a vertical focusing lens 7, a collimator 8, and an output lens 9.

[0022] In this architecture, the main direction of ion transport from the source to the subsequent mass analyzer is axial. Evaporation zone 1 and ionization zone 2 are arranged parallel to each other and together form the high-temperature ionization region at the front end. Ion output baffle 3 is located behind this region to define the extraction space; extraction electrode 4 is positioned behind ion output baffle 3 to form an accelerating extraction field. Subsequently, a multi-stage electrostatic lens spatial control group is formed by sequentially arranging a split focusing lens 5, a cylindrical focusing lens 6, and a vertical focusing lens 7; finally, the ion beam is filtered by a collimator 8 and an output lens 9 to achieve a final divergence angle.

[0023] During operation, the sample vaporizes in evaporation zone 1 and ionizes on the surface of high-temperature ionization zone 2. The positive ions generated by random thermal motion are directionally accelerated by extraction electrode 4 and then sequentially pass through the electrostatic field compression and edge trimming of each stage of lenses and collimation structure, causing the ion divergence angle to gradually converge and achieve spatial energy matching with the subsequent analyzer. Through this multi-level, layer-by-layer optical control structure design, the aberration distortion present in a single focusing electrode is overcome, and the overall precision of the focal spot is improved.

[0024] The evaporation and ionization core region, consisting of evaporation zone 1 and ionization zone 2, is made of rhenium, a high-melting-point metal. Both evaporation zone 1 and ionization zone 2 are 0.5 mm wide and 2.0 mm long. They are arranged parallel to each other, forming a 0.8 mm wide slit gap between them, parallel to the horizontal direction. The rear sides of evaporation zone 1 and ionization zone 2 maintain a precise distance of 0.5 mm from the ion output baffle 3. During operation, a direct current heats both zones. The evaporated neutral particles enter the high-temperature surface of ionization zone 2 and undergo thermal ionization. The precisely defined slit size and parallel position ensure a high initial symmetry in the generated thermal field and ion distribution, reducing beam asymmetry caused by hotspot shift.

[0025] For the extraction and acceleration region, the ion output baffle 3 includes a baffle body made of a high-temperature resistant metal plate and a drive mechanism connected thereto. A first central aperture is formed on the ion output baffle 3, which is 1.0 mm wide and 5.0 mm long. The extension direction of the aperture is parallel to the gap between the evaporation zone 1 and the ionization zone 2, and the ion output baffle 3 is 4.5 mm away from the extraction electrode 4. A power supply module is also provided within the device, which is electrically connected to the ion output baffle 3 and the extraction electrode 4. This power supply module is configured such that the potential distribution Φ(x,y,z) in the passive region between the two satisfies the Laplace equation, thereby achieving field equilibrium. The extraction electrode 4, located behind it, has a second central aperture 2.0 mm wide and 5.0 mm long. Its geometric center is aligned with the aperture direction, and the extraction electrode 4 is 4.5 mm away from the subsequent separate focusing lens 5. During operation, the balanced Laplace electric potential field enables the nascent ion cluster to smoothly enter the extraction electric field, effectively limiting the initial emission angle of the ions and suppressing ineffective edge scattering, further standardizing the geometric envelope shape of the initial accelerated ion beam.

[0026] Furthermore, the voltage configuration of the ion output baffle and the lead-in electrode satisfies the field equilibrium condition, making the electric field distribution in the region between them tend to be uniform. According to electrostatic field theory, the potential distribution in the passive region... Satisfies the Laplace equation:

[0027] A voltage V3 is applied at the axial position z3 where the ion output baffle is located, and a voltage V4 is applied at the axial position z4 where the lead-out electrode is located, thus establishing the boundary conditions:

[0028] The ratio of V3 to V4 was determined through simulation optimization to ensure the potential gradient... By maintaining a constant ion emission region, the initial ion energy is dispersed and controlled within +0.5 eV.

[0029] Combination Figure 5The split focusing lens 5 comprises two symmetrically arranged arc-shaped electrode plates. The arcs contract inward, forming an ion channel in the middle. The arc of the two electrode plates is set to 90 degrees, and the closest distance between the central regions is only 0.4 mm. The lead-out electrode 4 and the split focusing lens 5 are respectively connected to different DC voltage output terminals, forming an electrostatic immersion lens. The applied electric field satisfies the horizontal electrostatic lens focusing condition including the ion equivalent voltage parameter. During operation, a hyperbolic radial electric field is excited within the split configuration, which laterally compresses the passing ions and deflects large-angle stray ions, achieving preliminary purification and first-stage horizontal convergence of the ion beam.

[0030] Furthermore, the lead-out electrode and the separate focusing lens constitute an electrostatic immersion lens, and their voltage configuration satisfies the focusing conditions of an electrostatic lens in the horizontal direction:

[0031] in, The horizontal focusing focal length provided for the split focusing lens To extract the voltage of the electrodes, This is the voltage of the split focusing lens. This is the equivalent voltage corresponding to the initial energy of the ions, which is determined by the ionization band temperature and the ionization energy of the sample. The axial distance between the lead-out electrode and the split focusing lens. This is the horizontal focusing correction factor, which is related to the geometry of the curved electrode plate of the split focusing lens. With the above configuration, the ion beam achieves initial focusing in the horizontal direction.

[0032] Combination Figure 6 and Figure 7 The cylindrical focusing lens 6 is a cylindrical electrode structure with an inner diameter of 50 mm along the ion transport path. The vertical focusing lens 7 consists of three electrode plates 701, 702, and 703 spaced 5.0 mm apart along the axial direction. The middle electrode plate 702 is a pair of parallel semicircular electrodes with a diameter of 50.0 mm, and the spacing between the apertures of each electrode plate is 5.0 mm. The cylindrical focusing lens 6 and the vertical focusing lens 7 are connected to independent power supplies to form specific electric field gradients, approximately forming a single-plane quadrupole focusing configuration in the vertical direction. This allows the horizontal and vertical off-axis motions of ions to be independently decoupled under paraxial approximation conditions, and the trajectory evolution follows a linear differential equation related to the off-axis distance and the equivalent focal length of the lens. This electrode arrangement achieves compression in different directions of the cross-sectional dimension: the cylindrical shape provides global circumferential barrier constraint, while the vertical focusing lens 7 focuses on enhancing spatial convergence in the longitudinal direction, thereby smoothing and correcting the linear or rectangular diverging beam at the front end into a near-circular regular beam spot.

[0033] Furthermore, the focusing lens, in conjunction with the vertical focusing lens, enables independent focusing of the ion beam in both the horizontal and vertical directions. Under the paraxial approximation, the ion's lateral motion can be decoupled, and its trajectory is described by the following linear equation:

[0034]

[0035] in, , These represent the ion's off-axis distance in the horizontal and vertical directions as a function of the axial direction. Changes; , These represent the initial positions of the ions at the inlet of focusing lens 6. The initial divergence angle (slope); The horizontal equivalent focal length provided for the focusing lens, The equivalent focal length in the vertical direction provided for the vertical focusing lens 7.

[0036] The voltages of the focusing lens and the vertical focusing lens are optimized through simulation, so that... and The matching conditions are met, thereby obtaining an approximately circular cross-section ion beam with a beam spot ellipticity of less than 5% at the inlet of collimator 8.

[0037] Combination Figure 8 and Figure 9 The collimator 8 consists of equally spaced parallel grid-like electrode plates with uniform grid holes at the electrode edges and a cylindrical gap with a diameter of 13.0 mm at the center. The output lens 9, located at the end of the system, comprises three output electrode plates 901, 902, and 903, spaced 5.0 mm apart. Each plate is composed of two rectangular electrode plates spaced 3.0 mm apart. Each electrode plate has an independently adjustable DC voltage input terminal from the front of the lens group to the output lens 9. During operation, based on the pinhole imaging principle, the central gap of the collimator 8 acts as a light-passing aperture to intercept ions with excessive divergence angles, while the grid smooths and filters the edge field. Subsequently, low-divergence ion clusters pass through the rectangular slit of the output lens 9, achieving end-effector energy uniformity modulation. This process significantly reduces energy dispersion and parallelism divergence before injection into the mass spectrometer, improving the overall resolution of the instrument.

[0038] By simulating and optimizing the electrode structure and layout, the uniformity of electric and thermal field distribution is effectively improved, while significantly reducing ion energy dispersion and background noise interference, thus improving the stability and signal purity of the ion beam. Compared with the 30%-50% efficiency of traditional thermal ionization ion sources, this invention can achieve an ion transmission efficiency of over 80% under simulation conditions, significantly improving ion utilization.

[0039] To verify the transmission performance of the ion source device of this invention, the ion current intensity was measured at the outlet of the output lens using a Faraday cup and compared with the total ion current intensity generated in the evaporation and ionization zones. Ion transmission efficiency is defined as... :

[0040] in, The ion current intensity measured at the outlet of the output lens. The total ion current intensity generated in the evaporation and ionization zones is represented. To verify the transmission performance of the ion source device of this invention, SIMION simulation was used to statistically analyze the ion trajectory. Using ions passing through a cross-section of X ≥ 100 mm as the criterion for successful transmission, simulations were performed on 2000 initial ions, resulting in 1670 successfully transmitted ions, corresponding to an ion transmission efficiency of 83.5%. This efficiency reflects the performance of the ion source extraction and transmission structure and does not include the ionization efficiency of the thermal ionization process.

[0041] Figure 13 This is a flowchart of the ion beam formation and multi-stage control process of this thermal ionization ion source device. The workflow of this device includes four stages: S101 is the ion generation stage, where the sample is heated and evaporated into neutral atoms, which then undergo thermal ionization at high temperature to form positive ions. In this stage, the initial energy of the ions is low and their motion direction is randomly distributed; S102 is the ion extraction and initial acceleration stage, where ions are extracted from the source region and gain kinetic energy under the action of the extraction electric field, realizing the transformation from disordered thermal motion to directional motion, forming an initially accelerated ion beam; S103 is the multi-stage electrostatic lens spatial control stage, where the ion beam is spatially controlled by separate focusing lenses, focusing lenses, and vertical focusing lenses to achieve focusing and beam shape optimization in different directions, so that the ion beam gradually converges and improves spatial consistency; S104 is the collimation and output stage, where the ion divergence angle and energy distribution are screened and matched by collimators and output lenses, finally forming a low-divergence, high-parallelism ion beam and injecting it into the mass analyzer.

[0042] In S101, the sample is heated and evaporated into neutral atoms, which then undergo thermal ionization at high temperatures to form positive ions. In this stage, the ions have low initial energy and their motion is randomly distributed. This stage is achieved through the synergistic effect of evaporation zone 1 and ionization zone 2.

[0043] The evaporation zone 1 and ionization zone 2 are arranged parallel to each other and are both made of rhenium, a high-melting-point metallic material. During operation, the sample (such as a solid rhenium salt or the analyte coated on a tantalum strip) is placed on evaporation zone 1 and heated to 1200-1800 K using a direct current (dynamically adjusted according to the sample's volatility characteristics), causing the sample to evaporate into neutral atomic or molecular clusters. The evaporated neutral particles collide with the surface of ionization zone 2 during diffusion. The temperature of ionization zone 2 is maintained at 2000-2500 K. Under these high-temperature conditions, the neutral particles undergo surface thermal ionization, generating positive ions. At this stage, the ions have low initial energy and their movement direction is randomly distributed.

[0044] In S102, the ion extraction stage achieves ion beam orientation and initial acceleration through the extraction electric field formed by the ion output baffle 3 and the extraction electrode 4. The ion output baffle 3 is located behind the evaporation zone 1 and the ionization zone 2, 0.5 mm away from their geometric centers. The baffle is 1.0 mm thick and has a rectangular aperture of 1.0 mm (width) × 5.0 mm (length) in the center. This aperture is parallel to the evaporation zone-ionization zone slit, and the center line of the aperture coincides with the center line of the slit, which is used to define the ion emission area and suppress edge-scattered ions.

[0045] The extraction electrode 4 is positioned behind the ion output baffle 3, 4.5 mm away from it. The extraction electrode 4 is a flat plate electrode structure with an extraction aperture of 2.0 mm (width) × 5.0 mm (length) in the center, aligned with the center of the aperture in the baffle. A negative voltage of -800 V to -2000 V is applied to the extraction electrode 4 relative to the ionization band 2. The specific value is optimized based on the target ion mass and the required beam energy, forming an axial extraction electric field with a field strength of approximately 200-500 V / mm.

[0046] Under the influence of this extraction electric field, positive ions are drawn out of the ionization region and gain kinetic energy, realizing the transformation from disordered thermal motion to directed motion. After acceleration, the ions form an initial accelerated ion beam, at which point the ion beam energy is... ( (To extract voltage), the beam diverges, with a divergence angle of approximately 5°-10°.

[0047] In S103, the ion beam control stage uses a multi-stage electrostatic lens system consisting of a split focusing lens 5, a focusing lens 6, and a vertical focusing lens 7 to spatially control the ion beam and achieve focusing and beam shape optimization in different directions.

[0048] The separate focusing lens 5 is positioned behind the extraction electrode 4, 4.5 mm away, and is used for preliminary focusing of the ion beam. The separate focusing lens 5 includes two symmetrically arranged arc-shaped electrode plates, forming an ion channel between them. The arc of each electrode plate is 90°, and the distance between the two plates is 0.4 mm. A symmetrical bias voltage is applied to the two arc-shaped electrodes, creating an approximately hyperbolic radial electric field within the gap. According to electrostatic lens theory, its equivalent focal length f can be estimated as follows:

[0049] in The mass-to-ion ratio. The axial velocity is [value missing]. This structure not only provides horizontal focusing, but its asymmetric electric field can also deflect low-energy impurity ions, enabling preliminary mass screening.

[0050] The focusing lens 6 is located behind the split focusing lens 5 and has a cylindrical electrode structure with an inner diameter of 50 mm. It is used to focus the ion beam as a whole. A voltage is applied to the middle electrode of the focusing lens 6, and a lower bias voltage is applied to the front and rear electrodes to form an axisymmetric electrostatic barrier, thereby focusing the ion beam as a whole and reducing the beam envelope radius.

[0051] The vertical focusing lens 7 is positioned behind the focusing lens 6 and includes three electrode plates, with a distance of 5.0 mm between adjacent electrode plates. The middle electrode plate consists of a pair of semicircular electrodes arranged vertically opposite each other, with each semicircular electrode having a diameter of 50.0 mm. Since the upper and lower semicircular electrodes can be independently charged, they generate a strong gradient electric field in the Y direction (vertical direction), while the electric field is approximately uniform in the X direction (horizontal direction). According to the quadrupole field approximation in ion optics, this configuration is equivalent to a single-plane focusing lens, and its focusing intensity is proportional to the voltage difference between the electrodes. ,satisfy:

[0052] in The distance between the electrodes. This is the ion beam energy. This allows for the formation of a strong focusing field in the vertical direction, while maintaining weak focusing or divergence in the horizontal direction (X direction), enabling active control of the ion beam cross-sectional shape, gradually converging the beam and improving spatial consistency.

[0053] In S104, the ion beam output stage uses collimator 8 and output lens 9 to screen and match the ion divergence angle and energy distribution, ultimately forming a low-divergence, high-parallelism ion beam which is then injected into the mass analyzer.

[0054] The collimator 8 is located behind the vertical focusing lens 7 and includes several parallel grid-like electrode plates. Each grid-like electrode plate is evenly spaced and has several uniformly distributed grid holes. A cylindrical gap (light-transmitting aperture) with a diameter of 13.0 mm is opened at the center of the collimator 8. The edge electric field is homogenized through the grid structure, spatially filtering the ion beam and removing edge ions with a divergence angle greater than 3°, thus making the beam tend to be parallel. This angle filtering follows the pinhole imaging principle: if the collimator's light-transmitting aperture is... If the distance between it and the image plane of the preceding lens is L, then the maximum allowable divergence angle is... satisfy:

[0055] The output lens 9 is located behind the collimator 8 and has a three-unit parallel plate lens structure. It is used for final energy modulation and aberration correction of the ion beam. The lens includes: Three electrode plates, spaced 5.0 mm apart, are arranged parallel to each other. Each electrode plate consists of two rectangular electrode pieces, each measuring 20 mm (length) × 10 mm (height), spaced 3.0 mm apart. The central aperture is a rectangular channel measuring 3.0 mm × 10.0 mm. By optimizing the voltage distribution applied to the output lens 9, the ion beam divergence angle can be further compressed to... And match the acceptance requirements of subsequent quality analyzers.

[0056] Figure 10 A schematic diagram showing the voltage assignments for each electrode plate is provided, with the following voltage settings for each component: Evaporation zone 1 is applied with a +10000V DC voltage; ionization zone 2 is applied with a +10000V DC voltage; ion output baffle 3 is applied with a +9950V DC voltage; lead-out electrode 4 is applied with a +8000V DC voltage; split focusing lens 5 is applied with a +9095V DC voltage; focusing lens 6 is applied with a +4600V DC voltage; the three electrode plates 701, 702, and 703 of the vertical focusing lens 7 are applied with 0V, 500V, and 0V DC voltages respectively; collimator 8 is applied with a 0V DC voltage; and the three electrodes 901, 902, and 903 of the output lens 9 are applied with 0V, +1500V, and 0V DC voltages respectively. These voltage values ​​were determined based on ion optics simulation optimization to ensure maximum ion transport efficiency.

[0057] Figure 11 This is the interface for setting initial particle parameters in the ion source simulation. The particle swarm parameters are configured as follows: total number of particles is set to 2000, mass is set to 186 u, and charge is set to +1 e; the source position is uniformly distributed in the X direction, ranging from 0 to 0.8 mm; uniformly distributed in the Y direction, ranging from 25 to 27 mm; and a single value of 26.5 mm in the Z direction; the velocity direction adopts an angle plus kinetic energy scheme, with the azimuth angle following a Gaussian distribution and a mean of -90°. Standard deviation 20 The elevation angle follows a Gaussian distribution with a mean of 0. Standard deviation 20 The kinetic energy is uniformly distributed, ranging from 0 to 0.2. Flight start time set to 0 This parameter configuration is used to simulate the initial emission characteristics of ions in an electric field, ensuring that the simulation results are consistent with the behavior of actual ion sources.

[0058] Figure 12 The simulation results of the ion transport trajectory are shown, illustrating the complete path of the ion beam from the ion source through various lens systems to the output end under the aforementioned electrode voltage and initial particle parameter settings. The red trajectory line in the figure indicates that after passing through the evaporation zone, ionization zone, extraction electrode, and multiple focusing lenses, the ion beam achieves optimal focusing and collimation, and finally stably transmits to the mass analyzer inlet, verifying the rationality and effectiveness of the ion source system design.

[0059] When the test input is an initial ion flow of 2000 particles with a mass of 186u, the equivalent focal length of the split lens 5 and the equivalent focal length of the immersion lens between the lead-out electrode 4 and the split electrode 5, under voltage matching, enable the overall system to achieve perfect relay compression of the horizontal and vertical phases. Figure 12 Statistical analysis of the trajectories showed that 1670 ions successfully transported and stably passed through the axial decision section, and the system's ion transport efficiency was as high as 83.5% as evaluated by the Faraday cup. This indicates that the depth of the potential trap and the gradient layout inside the system have extremely high ion utilization.

[0060] The initial diffuse positive ions generated by the phase transition of neutral atoms after high-temperature evaporation and ionization are drawn into the Laplace field equilibrium region and initially extracted and accelerated. Subsequently, relying on the high-order non-uniform electrostatic field generated by different electrode structures (arc-shaped holes, cylindrical cavities, single-layer semi-circular electrodes, etc.), they undergo radial convergence, horizontal and vertical independent decoupling and shaping, and spatial edge defocusing filtering in the paraxial domain.

[0061] The device described in this application overcomes the severe phase space distortion and energy background tailing of traditional ion sources by using multi-plate voltage regulation with high degrees of freedom and pure structured physical cutting, significantly reducing the signal-to-noise ratio loss and maintaining a high transmission cross-section for long-term high efficiency.

[0062] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, processes, and procedures discussed in this application can be alternated, modified, rearranged, decomposed, combined, or deleted.

[0063] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of the claims of this application.

Claims

1. A thermal ionization source device, characterized in that, include: Evaporation zone; The ionization zone is arranged parallel to the evaporation zone; An ion output baffle with pores is provided and is located behind the evaporation zone and the ionization zone. An extraction electrode is provided, and the extraction electrode is located behind the ion output baffle. A split focusing lens has a symmetrical arc-shaped electrode gap, and the split focusing lens is disposed behind the lead-out electrode; A tubular focusing lens having a hollow tubular inner cavity, the tubular focusing lens being disposed behind the split focusing lens; A vertical focusing lens having a multi-layer electrode structure, wherein the vertical focusing lens is disposed behind the cylindrical focusing lens; A collimator, including a grid-like electrode sheet, is disposed behind the vertical focusing lens; An output lens includes multiple parallel electrode plates, and the output lens is disposed behind the collimator; The evaporation zone, ionization zone, ion output baffle, lead-out electrode, split focusing lens, cylindrical focusing lens, vertical focusing lens, collimator and output lens are arranged sequentially along the ion transport path.

2. The thermal ionization ion source device according to claim 1, characterized in that, The evaporation band and the ionization band are made of high-melting-point metal materials. The width of the evaporation band and the ionization band are both a first preset width, and the length of the evaporation band and the ionization band are both a first preset length. The evaporation band and the ionization band are arranged in parallel, forming a gap of a first preset slit width between them. The rear of the evaporation band and the ionization band is a first preset distance away from the ion output baffle.

3. The thermal ionization source device according to claim 1, characterized in that, The ion output baffle includes a baffle body and a driving mechanism. The driving mechanism is connected to the baffle body, and the baffle body is a high-temperature resistant metal plate. A first central hole is formed on the ion output baffle. The width of the first central hole is a second preset width, and the length is a second preset length. The extending direction of the first central hole is parallel to the gap between the evaporation zone and the ionization zone. The ion output baffle is a second preset distance away from the lead-out electrode. It also includes a power supply module, which is electrically connected to the ion output baffle and the lead-out electrode respectively. The voltage applied by the power supply module to the ion output baffle and the lead-out electrode is configured such that the potential distribution in the passive region between them satisfies the Laplace equation to achieve field equilibrium conditions.

4. The thermal ionization source device according to claim 1, characterized in that, The lead-out electrode has a second central aperture, the width of which is a third preset width and the length of which is a third preset length. The geometric center of the second central aperture coincides with the geometric center of the lead-out electrode and is parallel to the aperture on the ion output baffle. The lead-out electrode is a third preset distance away from the separate focusing lens.

5. The thermal ionization source device according to claim 1, characterized in that, The split focusing lens includes two symmetrically arranged arc-shaped electrode plates, an ion channel is formed between the two arc-shaped electrode plates, the curvature of the arc-shaped electrode plates is a preset curvature, and the closest distance between the two arc-shaped electrode plates is a fourth preset distance; The lead-out electrode and the separate focusing lens constitute an electrostatic immersion lens. They are respectively connected to different DC voltage output terminals, so that the electric field formed between them satisfies the horizontal electrostatic lens focusing condition including the ion equivalent voltage parameter.

6. The thermal ionization source device according to claim 1, characterized in that, The cylindrical focusing lens has a cylindrical electrode structure, and the cylindrical electrode has an inner cavity that runs through the ion transport path, with an inner diameter that is a first preset diameter.

7. The thermal ionization ion source device according to claim 1, characterized in that, The vertical focusing lens includes three electrode plates arranged sequentially along the ion transport path. The adjacent electrode plates are spaced a fifth preset distance apart. The center plate of the three electrode plates is a pair of semi-circular electrodes arranged vertically opposite each other. The planes on which the pair of semi-circular electrodes are located are parallel to each other and are in the same vertical cross-section. The diameter of the semi-circular electrodes is a second preset diameter. There is a gap between the electrode plates to allow ions to pass through. The width of the gap is a fourth preset width. The cylindrical focusing lens and the vertical focusing lens work together, and the two are connected to independent power supplies to form an electric field gradient, so as to achieve independent focusing and decoupling of the ion beam in the horizontal and vertical directions, so that the ion trajectory satisfies the linear equation relationship between off-axis distance and equivalent focal length under the paraxial approximation condition.

8. The thermal ionization source device according to claim 1, characterized in that, The collimator includes several parallel grid-shaped electrode plates, which are arranged at equal intervals along the ion transport path. Each grid-shaped electrode plate has several uniformly distributed edge grid holes. A cylindrical gap is formed in the central region of the collimator, and the diameter of the cylindrical gap is a third preset diameter.

9. The thermal ionization source device according to claim 1, characterized in that, The output lens includes three output electrode plates arranged in parallel along the ion transport path. The adjacent output electrode plates are spaced a sixth preset distance apart. Each output electrode plate is composed of two rectangular electrode plates spliced ​​together. There is a gap between the two rectangular electrode plates. The pore width of the gap is a fifth preset width.

10. The thermal ionization source device according to claim 1, characterized in that, The ion output baffle, lead-out electrode, split focusing lens, cylindrical focusing lens, vertical focusing lens, collimator, and output lens are each equipped with an independently adjustable DC voltage input terminal.

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