Mass spectrometry imaging apparatus and method

Abstract

The application provides a mass spectrometry imaging device and method. The device comprises an adjustment channel for adjusting the flight direction and vertical direction offset of the ion beam emitted by the emission unit, so that the ion beam flies through the ion lens focusing beam spot shape at different angles, and is bombarded to the target area of the sample target along the optical axis; a plurality of deflection plate groups are arranged in the adjustment channel, each deflection plate group comprises four deflection plates of the same size and arranged oppositely, and the plurality of deflection plate groups are arranged horizontally; each deflection plate group is connected with an adjustable voltage signal, the amplitude of the adjustable voltage signal is associated with the target flight direction of the ion beam, the size of the deflection plate and the arrangement position of each deflection plate group in the adjustment channel through which the ion beam passes; and a detection unit is arranged for receiving the secondary ions generated after the ion beam bombarded to the surface of the sample target in the adjustment channel. The mass spectrometry imaging device and method are used for accurately positioning the sampling point of the secondary ion mass spectrometry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of secondary ion mass spectrometry, and in particular to a mass spectrometry imaging device and method. BACKGROUND

[0002] As a high-sensitivity and high-spatial-resolution surface analysis technique, secondary ion mass spectrometry plays a key role in the fields of material science, geology, biology, etc. By ion beam bombardment of the sample surface to generate secondary ions, and by mass-to-charge ratio separation and detection, it can achieve analysis of element composition, isotope distribution and chemical state at the nanometer to micrometer scale, and is suitable for studying the composition characteristics of the microstructure of the material surface and near-surface, providing an important means for understanding the microstructure and performance correlation of matter.

[0003] Currently, the selection of sampling points in secondary ion mass spectrometry analysis mainly relies on optical image observation and the experience of the operator. The general area of the sample surface is determined through an optical system or a scanning electron microscope, based on the preliminary understanding of the sample structure, the position possibly containing the target component is manually selected as the sampling point, and the selected position is analyzed by single-point analysis using the secondary ion mass spectrometry equipment.

[0004] The existing sampling point selection method has obvious limitations: on the one hand, the samples in the fields of geology, biology, etc. have complex and fine microstructures, and are easily affected by interfering elements in the environment, making it difficult to accurately locate the target area relying only on optical images and experience, which may cause the sampling point to deviate from the true analysis area, resulting in loss of target information; on the other hand, the fixed ion beam bombardment and extraction structure cannot balance the beam spot quality and scanning requirements, limiting the accuracy and reliability of the sampling point selection. SUMMARY

[0005] In view of this, the present application provides a mass spectrometry imaging device and method for accurately locating the sampling point of secondary ion mass spectrometry.

[0006] Specifically, the present application is realized by the following technical solutions:

[0007] The first aspect of the present application provides a mass spectrometry imaging device, which comprises:

[0008] a transmitting unit for transmitting an ion beam to a sample target;

[0009] an adjusting channel for adjusting the flight direction and vertical direction offset of the ion beam emitted by the transmitting unit, so that the ion beam flies at different angles through the ion lens focusing beam spot shape and along the optical axis, and bombards the target area of the sample target;

[0010] A plurality of deflection plate groups are arranged in the adjustment channel, each deflection plate group includes four deflection plates of the same size arranged oppositely, and the plurality of deflection plate groups are arranged horizontally; each deflection plate group is connected to an adjustable voltage signal, and the amplitude of the adjustable voltage signal is associated with the target flight direction of the ion beam, the size of the deflection plate, and the arrangement position of each deflection plate group in the adjustment channel through which the ion beam passes;

[0011] A detection unit is configured to receive secondary ions generated after the ion beam passing through the adjustment channel strikes the sample target surface.

[0012] The second aspect of the present application provides a mass spectrometry imaging method, which comprises:

[0013] A transmission unit transmits a primary ion beam to a sample target surface;

[0014] An adjustment channel adjusts the flight direction and vertical offset of the primary ion beam, and sputters secondary ions;

[0015] A detection unit receives the sputtered secondary ions to obtain a mass spectrum image.

[0016] The mass spectrometry imaging device and method provided by the present application can complete the adjustment of the ion beam with a specified flight direction and a beam spot shape unchanged through the adjustment of the multiple deflection plate groups with adjustable voltages and the cooperation between the voltages, so that the beam spot shape of the position actually struck by the ion beam is basically consistent with the beam spot shape of the position struck by the ion beam along the optical axis, the ion beam striking with a specified flight direction is realized, and the effect of mass spectrometry imaging is improved. On the one hand, the adjustment channel can simultaneously adjust the flight direction and the vertical offset of the ion beam through the multiple groups of horizontally arranged deflection plates, so as to ensure that the flight direction of the ion beam is basically consistent with the actual flight condition, avoid the beam spot distortion caused by the offset amount of the ion beam deviating from the optical axis when passing through the focusing lens and the degree of inclination of the ion beam flight direction when being incident to the ion lens, and ensure the stability and consistency of the ion beam striking the target region of the sample target, thereby providing a reliable ion beam source for subsequent detection. On the other hand, the amplitude of the adjustable voltage signal connected to each deflection plate group is associated with the target flight direction of the ion beam, the size of the deflection plate, and the arrangement position, so that the device can dynamically adjust the voltage according to the actual demand, accurately match the parameters of the ion beam, and expand the application range of the device. Through stable ion beam striking and accurate target region positioning, the detection unit can more accurately receive the secondary ions generated on the sample surface, reduce the detection error caused by the unstable ion beam parameters or the deviation of the striking position, lay a foundation for the accurate positioning of the sampling points in the secondary ion mass spectrometry analysis, and improve the reliability of the mass spectrometry imaging result. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural schematic diagram of a mass spectrometry imaging device according to an embodiment of the present application;

[0018] Figure 2 A schematic diagram of the xy horizontal cross section of the adjustment channel in the case of setting two deflection plate groups, as shown in an exemplary embodiment of this application;

[0019] Figure 3 This is a flowchart of an embodiment of the mass spectrometry imaging method provided in this application;

[0020] Figure 4 This is a schematic diagram illustrating the division of the maximum scan region as an exemplary embodiment of this application.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1: Transmission unit;

[0023] 2: Adjust the channel;

[0024] 3: Detection unit;

[0025] 21: Deflection plate assembly;

[0026] 22: Single deflection plate. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0028] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0030] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0031] Figure 1This is a schematic diagram of the structure of a first embodiment of the mass spectrometry imaging device provided in this application. Please refer to... Figure 1 The apparatus provided in this embodiment may include:

[0032] Emission unit 1 is used to emit an ion beam toward the sample target;

[0033] Adjustment channel 2 is used to adjust the flight direction and vertical offset of the ion beam emitted by the emission unit 1, so that the beam spot shape after the ion beam flies at different angles and is focused by the ion lens is the same as when it flies along the optical axis, and bombards the target area of ​​the sample target.

[0034] The adjustment channel 2 is provided with multiple deflection plate groups 21. Each deflection plate group 21 includes four deflection plates 22 of the same size and arranged opposite each other. The multiple deflection plate groups 21 are arranged horizontally. Each deflection plate group 21 is connected to an adjustable voltage signal. The amplitude of the adjustable voltage signal is related to the target flight direction of the ion beam, the size of the deflection plate 22, and the arrangement position of each deflection plate group 21 in the adjustment channel through which the ion beam passes.

[0035] The detection unit 3 is used to receive secondary ions generated after the ion beam in the adjustment channel 2 bombards the surface of the sample target.

[0036] Specifically, the emitting unit is used to emit an ion beam towards the sample target. The type of ions emitted by the ion beam is set according to actual needs, and the ion beam type can include O + Cs + Ar + The sample target is a component used to hold the sample to be analyzed. It is used to fix the sample and ensure that the sample surface is within the range that the ion beam can bombard, so as to facilitate the subsequent interaction between the ion beam and the sample and the generation of secondary ions. In other words, the ion beam emitted by the emission unit acts on the sample surface of the sample target. When the ion beam is emitted to the sample surface, it will cause the atoms or molecules on the sample surface to be sputtered out to form charged secondary ions. These secondary ions carry information such as the elemental and chemical state of the sample.

[0037] Furthermore, the diameter of the ion beam is determined based on the sample size. If the sample is macroscopic (such as centimeter-scale geological slices or large-area thin film materials), the ion beam diameter can be selected from micrometers to nanometers according to the analytical requirements: when macroscopic regional distribution is required, a larger beam spot (such as micrometers) can be used to improve scanning efficiency; when microstructure needs to be observed (such as nanoparticles or interface defects), a smaller beam spot (such as less than 10 nanometers) should be selected to ensure high spatial resolution; if the sample is microscopic (such as micrometer-scale cells or nanoparticles), the ion beam diameter needs to be smaller than or close to the sample size. For example, when analyzing nanoparticles with a diameter of 500 nanometers, an ion beam with a diameter ≤500 nanometers should be selected to avoid beam spot covering the substrate area and causing signal interference, ensuring that only the secondary ion signal of the sample itself is collected.

[0038] Furthermore, the detection unit typically includes an extraction module, a mass analyzer, and a receiver. The extraction unit extracts secondary ions and transmits them to the mass analyzer for focusing and separation. The focused and separated secondary ions are received and detected by the receiver to obtain the signal intensity of the target element / isotope, and then a mass spectrometry image is generated based on this information.

[0039] Furthermore, during the process of the ion beam being emitted from the emitting unit to the sample surface, in order to ensure that the shape of the ion beam after being focused by the ion lens is the same as the flight direction of the optical axis at the front of the focusing edge of the ion lens, an adjustment channel is set between the emitting unit and the sample target. The adjustment channel adjusts the flight direction and vertical offset of the ion beam emitted from the emitting unit. It can be understood that the flight direction of the ion beam in the adjustment channel is a combination of horizontal and vertical velocities. Since the horizontal velocity remains constant and the same as the initial horizontal velocity, the change in the vertical velocity causes a vertical displacement of the ion beam in the adjustment channel. In order to ensure that the shape of the ion beam spot after being focused by the ion lens, regardless of the angle at which the ion beam passes through the ion lens, is the same as the shape of the ion beam spot after being focused along the optical axis, it is necessary to adjust the voltage of the deflection plate in the adjustment channel to control the flight direction and vertical offset of the ion beam. Displacement; ensuring that the beam spot shape of the ion beam hitting the sample target at different angles is the same as the beam spot shape hitting the sample target along the optical axis ensures the accuracy and comparability of the acquired secondary ion data; the stability of the beam spot shape is crucial to the detection accuracy, as the beam spot shape directly affects the morphology of the area where the ion beam bombards the sample target; during the movement of the ion beam, the beam spot shape changes with the incident tilt angle of the ion beam and the offset of the optical axis, resulting in stretching, twisting, etc. The actual effective range of the same ion beam bombarding the sample will change under different flight directions, leading to instability in the secondary ion generation area. This makes it impossible for the detected secondary ion signal to accurately correspond to a specific position and area on the sample, thus affecting the accuracy of judging information such as the distribution and concentration of sample elements and interfering with the reliability of mass spectrometry imaging results. Therefore, maintaining the stability of the beam spot shape is essential to ensure that the beam spot shape is consistent with each ion beam bombardment, making the detection data comparable and reliable.

[0040] Furthermore, taking a two-deflection-plate assembly as an example, Figure 2 A schematic diagram of the xy-axis horizontal cross-section of the adjustment channel in the case of setting two deflection plate groups, which is an exemplary embodiment of this application, is shown in the following figure. Figure 2 The adjustment channel contains multiple deflection plate assemblies 21. The adjustment channel can be square or cylindrical. Each deflection plate assembly 21 in the adjustment channel contains four deflection plates 22 of the same size, arranged opposite each other. Figure 2 The vertical cross-sectional schematic diagram shows two deflection plate assemblies. Each deflection plate assembly 21 includes four deflection plates 22 arranged opposite each other in the adjustment channel. An ion lens is located at the outlet of the adjustment channel. The center of the ion lens and the center of the deflection plates are both on the optical axis. The inner diameter of the ion lens is half the distance between the deflection plates. Furthermore, if the shape of the adjustment channel is a cylindrical pipe, in addition to... Figure 2In addition to the horizontal cross-sectional diagram shown, two deflection plates are also installed at the vertical position of the adjustment channel (yz direction) at a 90-degree angle to the horizontal deflection plate. That is, four deflection plates are simultaneously arranged on the inner wall of the adjustment channel at the same location. One set consists of a first pair of vertically oriented deflection plates, arranged vertically opposite each other; the other set consists of a second pair of horizontally oriented deflection plates, arranged horizontally opposite each other. The voltage values ​​of the two opposing deflection plates are the same, but their polarities are opposite. The two pairs of deflection plates are spatially perpendicular to each other, achieving control of the ion beam from both vertical and horizontal dimensions. When the ion beam enters the adjustment channel and passes through the area between the deflection plates, the adjustable voltage signal applied to the deflection plates creates an electric field around them. The ion charges in the ion beam are subjected to an electric force under the influence of this electric field. According to the law of action of the electric field force, the trajectory of the ions changes, thereby achieving adjustment of the ion beam direction. By controlling the amplitude and polarity of the voltage signal on each deflection plate group, the magnitude and direction of the electric field force on ions at different positions in the ion beam can be changed in a targeted manner, thereby achieving coordinated control of the ion beam flight direction and vertical offset, so that the ion beam can both reach the required target flight direction and maintain the beam spot shape, in order to meet the requirement of accurately bombarding the target area of ​​the sample.

[0041] Furthermore, the inlet of the adjustment channel is connected to the emission unit, and an ion lens is provided at the outlet of the adjustment channel. The device also includes a voltage adjustment unit, which is connected to each deflection plate group. The voltage adjustment unit is used to calculate the directional voltage based on the direction requirement of the ion beam bombarding the sample target, calculate the distance adjustment voltage based on the directional voltage, set the voltage of the N deflection plate groups farthest from the ion lens as the directional voltage, and set the voltage of the M deflection plate groups closest to the ion lens as the distance adjustment voltage. The flight direction of the ion beam is controlled according to the directional voltage, and the vertical offset of the ion beam after directional adjustment is controlled according to the distance adjustment voltage, so that the displacement of the ion beam perpendicular to the emission direction after directional adjustment is zero compared with that before directional adjustment.

[0042] Specifically, the inlet of the adjustment channel is connected to the emission unit to ensure that the ion beam emitted by the emission unit can smoothly enter the adjustment channel for processing; an ion lens is provided at its outlet, which can further focus the adjusted ion beam and optimize the beam spot quality. The ion beam adjusted by the adjustment channel is focused at a preset position point of the ion lens, so that the ion beam bombards the target area of ​​the sample target after being focused by the lens.

[0043] Furthermore, within the same deflection plate group, minute displacement of the ion beam can be controlled by applying a small voltage difference. Specifically, for small-range adjustments in the vertical direction, a slight voltage change can be applied to the directional voltage. When the voltage of the upper deflection plate is slightly higher than that of the lower one, the ion beam experiences an upward electric field force, resulting in a slight upward shift; conversely, it shifts downward. The voltage difference and the shift amount are approximately linearly related. Similarly, small-range adjustments in the horizontal direction can be achieved through a small voltage difference in the vertical directional voltage, allowing for precise control of the ion beam's left and right shift.

[0044] Furthermore, the steps for calculating the directional voltage based on the required direction of the ion beam bombardment of the sample target include:

[0045] (1) Determine the incident angle of the ion beam onto the ion lens according to the directional requirements;

[0046] Specifically, the core function of an ion lens is to alter the trajectory of an ion beam through the action of an electric field. The angle of incidence of the ion beam when it enters the lens (i.e., the angle between the ion beam and the optical axis of the lens) directly determines its exit direction after passing through the lens. The directional requirement refers to the specific location (such as a point within a scanning area determined by optical imaging) that the ion beam must ultimately strike. To ensure the ion beam accurately reaches this target location after passing through the ion lens, it is necessary to first deduce in reverse: based on the relative geometric relationship between the target location and the lens, calculate the necessary angle of incidence for the ion beam to enter the lens. Only an ion beam with this angle, after being focused by the ion lens, can reach the target point along a predetermined path.

[0047] Furthermore, experiments can be conducted to determine the different positions of the sample after the ion beam is incident on the ion lens at different incident angles, thereby establishing the geometric relationship between the bombardment position and the incident angle. In subsequent use, the corresponding incident angle can be obtained by inputting the positional relationship between the bombardment position and the optical axis into the geometric relationship.

[0048] For example, if the target position is 5mm to the right of the lens optical axis, it is necessary to calculate through geometric optics that the ion beam must be incident on the ion lens at an incident angle of 3° (tilted to the right relative to the optical axis) in order to accurately bombard the target position after being deflected by the ion lens.

[0049] (2) Determine the directional voltage based on the incident angle.

[0050] Specifically, the incident angle of the ion beam is determined by its direction of motion before entering the lens, and this direction can be controlled by the directional voltage of the deflector plate. The deflector plate generates an electric field by applying a voltage, and this electric field exerts a Coulomb force on the charged ion beam, causing it to deflect before entering the lens, thus obtaining the desired incident angle. Therefore, a definite functional relationship between the incident angle and the directional voltage can be obtained through experimental calibration or theoretical derivation. Once the desired incident angle is determined in the first step, the corresponding directional voltage value can be derived from this functional relationship. When this directional voltage is applied, the electric field generated by the deflector plate precisely enables the ion beam to obtain the target incident angle, laying the foundation for precise positioning under the subsequent lens action.

[0051] Please continue to refer to Figure 1 The mass spectrometry imaging device also includes a voltage adjustment unit. This unit calculates the directional voltage based on the vertical offset of the ion beam from the optical axis when it bombards the sample target, and controls the flight direction of the ion beam accordingly. Based on the directional voltage, a distance adjustment voltage is further calculated, which controls the vertical offset of the ion beam. Furthermore, the deflection plates are grouped according to their distance from the ion lens. The voltage of the farthest N-group deflection plates is set as the directional voltage, and this group is responsible for controlling the flight direction of the ion beam. By applying the directional voltage, the ion beam obtains the desired motion direction. The voltage of the closest M-group deflection plates is set as the distance adjustment voltage, and this group is responsible for adjusting the vertical offset of the ion beam. The N-group and M-group deflection plates work together; under the influence of the directional voltage, the flight direction of the ion beam is effectively controlled, meeting the directional requirements for bombarding the sample target. The distance adjustment voltage applied to the ion beam ensures that the displacement of the ion beam perpendicular to the emission direction is zero compared to the ion beam before directional adjustment. This means that after the ion beam's flight direction is adjusted, when it bombards the target area of ​​the sample target, the beam spot shape distortion caused by the change in flight direction is avoided, ensuring the accuracy and stability of the beam spot shape each time the ion beam hits the sample.

[0052] Understandably, when bombarding a sample on a target, it is necessary to sequentially modify the position of each ion bombardment on the sample to obtain elemental information at different positions. A voltage is applied to the ion beam using deflection plates to change the flight direction of the ion beam. The flight direction of the ion beam refers to the incident angle of the ion beam when it is incident on the ion lens. However, the change in the voltage applied to the ion beam by the deflection plates causes a vertical offset in the vertical direction of the ion beam during flight. The vertical offset causes distortion of the beam spot shape when it hits the sample, which in turn leads to inconsistency in the elemental information of the sample collected each time. Therefore, it is necessary to set the voltage of the M deflection plate group after the N deflection plate group to the pitch voltage, and use the pitch voltage to correct the vertical offset of the ion beam caused by the change in the pitch voltage. It is understandable that the voltage control of a pair of deflecting plates in the vertical direction is described here only. Similarly, the voltage control principle of a pair of deflecting plates in the horizontal direction is the same as that of a pair of deflecting plates in the vertical direction. By forming a deflecting plate group with two pairs of deflecting plates in the horizontal and vertical directions, the flight direction and vertical offset of the ion beam are ultimately controlled.

[0053] Specifically, the motion of the ion beam between the deflection plates follows the parabolic trajectory of charged particles in a uniform electric field. Along the axis of the adjustment channel (set as the x-axis), the ion beam is not subject to electric force and moves in uniform linear motion. In the direction perpendicular to the axis (y-axis), the ion beam is subject to a constant electric force in the electric field of the deflection plates and moves in uniformly accelerated linear motion.

[0054] For further details, please refer to [link / reference]. Figure 2 The specific steps for calculating the adjustment voltage based on the adjustment voltage include:

[0055] (1) Obtain the size information of each deflection plate;

[0056] Specifically, the dimensional information of each deflection plate includes the length of the deflection plate and the spacing between the relatively set deflection plates in each deflection plate group. The length of each deflection plate and the spacing between the relatively set deflection plates in each deflection plate group can be obtained based on design parameters or physical measurements.

[0057] (2) Determine the relative positional relationship between adjacent deflection plate groups;

[0058] Specifically, the relative positional relationship refers to the distance between adjacent deflection plate groups. Please refer to [reference needed]. Figure 2 ,by Figure 2 Taking the two deflection plate groups shown as an example, the coordinates of the rightmost edge of the left deflection plate group and the rightmost edge of the right deflection plate group are measured. The relative positions of the adjacent deflection plate groups are obtained by calculating the difference between the coordinates of the rightmost edges. It should be noted that the relative positional relationship of each adjacent deflection plate group is the same in the adjustment channel.

[0059] (3) Determine the minimum distance between the plurality of deflection plate groups and the ion lens;

[0060] Specifically, determine the deflection plate group that is closest to the ion lens among the multiple deflection plate groups, and measure the distance between the edge of the deflection plate group closest to the ion lens and the ion lens, which is taken as the minimum distance.

[0061] (4) Calculate the voltage transformation coefficient based on the size information, relative positional relationship, and minimum spacing;

[0062] (5) Calculate the adjustment voltage based on the product of the voltage transformation coefficient and the adjustment voltage.

[0063] For specific details, please continue with the parameters. Figure 2 Taking an adjustment channel with two deflection plate groups as an example, the two deflection plate groups in the adjustment channel are divided into an orientation deflection plate group and a distance deflection plate group according to their distance from the ion lens. The length 'a' of the deflection plate and the distance 'd' between the two deflection plates in the orientation deflection plate group are obtained based on the physical parameters of the deflection plates. It should be noted that the distance between the two deflection plates in each deflection plate group is the same in the adjustment channel. Further, the endpoint coordinates of the right edge of any deflection plate in the orientation deflection plate group and the endpoint coordinates of the left edge of any deflection plate in the distance deflection plate group are obtained. The difference between the endpoint coordinates of the right and left edges is used to obtain the horizontal distance 'b' between the orientation deflection plate group and the distance deflection plate group. The endpoint coordinates of the right edge of any deflection plate in the distance deflection plate group and its horizontal position in the ion lens under the same vertical coordinate are obtained, and the difference is used to obtain the minimum distance 'c' between the distance deflection plate group and the ion lens. The directional deflection plate group has a directional voltage of V1, and the pitch deflection plate group has a pitch voltage of V2.

[0064] Furthermore, the initial emission energy E of the ion beam is obtained from the emission unit parameters, the ion charge q and ion mass m are determined according to the ion type of the ion beam, and the initial horizontal velocity of the ion in the horizontal direction is calculated. At this point, the initial vertical velocity of the ion beam is 0;

[0065] Furthermore, based on the dimensions of each deflector plate (length), the relative distance between adjacent deflector plate groups, and the minimum spacing, the first time the ion beam passes through each deflector plate is calculated. The second time the ion beam passes through the relative positions of adjacent deflector plate groups and the third time when the ion beam passes through the minimum spacing. Based on kinematic principles, it can be determined that the ion beam accelerates when passing through the first deflection plate group. The first acceleration, the first vertical offset, and the first vertical velocity of the ion beam when leaving the first deflection plate group can be calculated. The first acceleration, the first vertical offset, and the first vertical velocity can be calculated using the following formulas:

[0066] ;

[0067] ;

[0068] ;

[0069] in, It is an ionic charge;

[0070] This is the voltage for directional adjustment;

[0071] It refers to the ion mass;

[0072] For spacing;

[0073] The length of a single deflection plate;

[0074] The initial horizontal velocity of the ion beam is given.

[0075] Furthermore, after leaving the first deflection plate group and before reaching the second deflection plate group, the ion beam moves at a constant speed within the horizontal distance between the two deflection plate groups. The second vertical offset of the ion beam during its horizontal movement can be calculated using the following formula:

[0076] ;

[0077] in, This is the horizontal distance between the two deflection plate groups.

[0078] Furthermore, the ion beam reaches the second deflection plate group with a first vertical velocity and undergoes acceleration within the second deflection plate group. Based on kinematic principles, the second acceleration, third vertical offset, and second vertical velocity of the ion beam upon leaving the second deflection plate group can be calculated using the following formulas:

[0079] ;

[0080] ;

[0081] ;

[0082] in, It is an ionic charge;

[0083] This is the voltage for directional adjustment;

[0084] It refers to the ion mass;

[0085] For spacing;

[0086] The length of a single deflection plate;

[0087] The initial horizontal velocity of the ion beam;

[0088] This is the adjustable voltage.

[0089] Furthermore, the ion beam leaves the second deflection plate group and moves at a constant speed within the minimum spacing before finally reaching the ion lens. The fourth vertical offset of the ion beam within the minimum spacing can be calculated using the following formula:

[0090] ;

[0091] in, This is the minimum spacing.

[0092] Therefore, the total vertical offset is calculated based on the sum of the first, second, third, and fourth vertical offsets:

[0093] ;

[0094] Furthermore, to make the total vertical offset zero, substituting the calculation formulas for each of the above vertical offsets into the equation, we finally obtain:

[0095] ;

[0096] in, This represents the voltage transformation coefficient.

[0097] When adjusting the directional voltage to regulate the speed of the ion beam, the corresponding adjustment voltage is calculated based on the product of the voltage conversion coefficient and the adjusted directional voltage. This ensures that the beam spot shape hitting the sample target at different angles is the same as the beam spot shape hitting the sample target along the optical axis.

[0098] By combining dimensional information, relative positional relationships, and minimum spacing, the voltage transformation coefficient is derived through kinematic formulas, transforming the relationship between structural parameters and voltage into a clear mathematical one. The voltage transformation coefficient enables dynamic matching between the directional voltage and the pitch voltage. When the directional voltage is adjusted due to the ion beam direction requirements, the pitch voltage can be updated synchronously through the voltage transformation coefficient, ensuring that both always meet the balance condition for beam spot shape correction. By offsetting the beam spot shape distortion caused by the offset of the ion beam due to the electric field force during the directional process (i.e., the total offset in the vertical direction), it ensures that the ion beam still bombards the sample target along the preset path after the flight direction changes, avoiding beam spot shape changes caused by direction changes.

[0099] Furthermore, the device also includes an optical imaging module for optical imaging of the sample target. The device is also used to determine the core deflection plate group based on the voltage magnitude relationship between multiple deflection plate groups, and to determine the target area based on the optical image and the scanning range of the core deflection plate.

[0100] Specifically, optical images are used to determine the position of the sample on the target and the specific area to be scanned. Optical imaging technology images the target surface, providing a visual morphological reference for subsequent target region localization. The core deflection plate group is determined based on the voltage conversion coefficient. The directional voltage and pitch voltage of different deflection plate groups must satisfy a voltage conversion coefficient relationship, with the directional voltage adjustment range of a particular deflection plate group being the smallest, becoming the boundary condition limiting the overall scanning range. If the scanning range is calculated based on the maximum pitch voltage of other deflection plate groups, it will exceed the voltage operating range of the core group and cannot be achieved. For example, when the directional voltage of a certain deflection plate group only supports a maximum of ±200V, while the pitch voltage of other deflection plate groups can reach ±300V, the actual maximum scanning range can only be determined by the directional voltage due to the voltage conversion coefficient limitation. Therefore, the core deflection plate group refers to the deflection plate group that, due to its smallest voltage range and constraint by the voltage conversion coefficient, becomes the upper limit of the overall scanning range; its voltage boundary directly defines the largest physical area that the ion beam can bombard. It should be noted that after imaging the sample target surface using optical imaging technology to obtain the sample's morphological features and determine the specific area to be scanned on the sample, the scanning range determined by the optical system is itself relatively small, far below the voltage operating limit of the core deflection plate assembly. Therefore, even if the core deflection plate assembly limits the overall maximum scanning range, the required scan will not be impossible due to exceeding its voltage range. For example, if the core deflection plate assembly's adjustment voltage supports a maximum of ±200V (corresponding to the system's maximum scanning range), and the small-range scan determined by the optical system only requires ±50V voltage adjustment, then the scan is entirely within the core assembly's operating range and can be stably achieved.

[0101] By selecting the core deflection plate in this way, it can be ensured that the target area is within the actual bombardment range of the ion beam, thus avoiding positioning failure caused by exceeding the device's control capabilities.

[0102] Furthermore, the optical imaging module acquires high-resolution images of the sample target surface. Operators can identify the microstructures to be analyzed from these images and preliminarily delineate the approximate area to be analyzed. The scanning range corresponding to the maximum voltage of the core deflection plate assembly determines the actual physical area that the ion beam can bombard. Areas outside this range cannot be covered by the ion beam. The mass spectrometry imaging device matches the preliminarily delineated area in the optical image with the scanning range of the core deflection plate assembly, ensuring that the target area is both contained within the structure of interest shown in the optical image and within the physical boundary that the ion beam can scan, ultimately determining the precise target area for ion beam bombardment.

[0103] Furthermore, the sample is fixed on a sample target, and the surface of the sample target is optically imaged using an optical imaging module to obtain a direct image of the sample's microstructure. Based on this, potential analyte regions containing the target components are initially screened. The core deflection plate group is determined based on the voltage ratio of the multiple deflection plate groups, and the maximum scanning area is calculated based on its voltage boundary. The analyte region selected from the optical image is matched with the maximum scanning area to determine the target area for the first ion beam bombardment. The emission unit emits an ion beam, and the flight direction and vertical offset are adjusted via the channel to bombard the target area. The detection unit receives the secondary ions and generates a mass spectrometry image. After one bombardment, the target area is updated according to the analytical requirements, and the above adjustment and bombardment process is repeated until the analyte region is covered. It should be noted that the target area is the specific location of each bombardment, and its size is necessarily less than or equal to the maximum scanning area. The target area is a further defined sub-region from the analyte region selected from the optical image; that is, the target area is contained within the analyte region. The optical image provides morphological analysis guidance, while the target area is the specific range of bombardment that can be performed under this guidance, combined with the actual scanning capability of the device.

[0104] The mass spectrometry imaging device provided in this embodiment achieves precise positioning of secondary ion mass spectrometry sampling points through the coordinated action of the emission unit, adjustment channel, and detection unit. Each deflector plate group is uniformly sized and relatively positioned. Combined with an adjustable voltage signal linked to the ion beam target flight direction and deflector plate parameters, a symmetrical electric field distribution counteracts the interference of directional changes on the beam spot shape, ensuring the beam spot always maintains its initial shape. This resolves the contradiction of inevitable distortion during directional adjustment in traditional devices, providing a consistent ion beam shape for stable bombardment. Furthermore, by deriving the mathematical relationship between deflector plate size, spacing, and the minimum spacing of the ion lenses, a voltage transformation coefficient is obtained, ensuring that the pitch voltage is always dynamically matched with the directional voltage. This counteracts the vertical displacement during ion beam acceleration, avoiding trajectory deviation caused by directional changes and reducing beam spot shape deviation. Optical imaging provides a visual reference of the sample surface microstructure, while the core deflector plate group defines the physically accessible range. The target area formed by the intersection of these two elements avoids both visible but unreachable invalid areas in the optical image and valueless blank areas within the device's physical range. This ensures that the target area for each bombardment is within a meaningful and achievable precise range, improving the stability of ion beam bombardment, the accuracy of control, and the reliability of detection.

[0105] Corresponding to the aforementioned embodiment of a mass spectrometry imaging device, this application also provides an embodiment of a mass spectrometry imaging method.

[0106] Figure 3 This is a flowchart of an embodiment of the mass spectrometry imaging method provided in this application. Please refer to... Figure 3 The method provided in this embodiment includes:

[0107] S101, The emission unit emits a single ion beam toward the surface of the sample target;

[0108] S102. Adjust the channel to adjust the flight direction and vertical offset of the primary ion beam, and sputter secondary ions;

[0109] S103. The detection unit receives the sputtered secondary ions and obtains a mass spectrometry image.

[0110] Specifically, the emission unit, acting as the source of the ion beam, emits a primary ion beam onto the sample target surface, providing the initial source for subsequent sample bombardment. The adjustment channel regulates the emitted primary ion beam through multiple horizontally positioned deflection plates and associated adjustable voltage signals, adjusting the beam's flight direction and vertical offset to ensure stable beam shape while changing its flight direction. This ultimately bombards the sample target surface and sputters secondary ions, achieving precise targeting of the ion beam to the target area. The sputtered secondary ions are then analyzed by the extraction unit and mass analyzer before finally being processed by the detection unit. If simply described as a detection unit, without the process of separating different elements, it cannot achieve signal intensity statistics for a specific element, thus hindering mass spectrometry imaging.

[0111] The extraction unit extracts secondary ions, which are then transmitted to a mass analyzer for focusing and separation. The focused and separated secondary ions are received and detected by a receiver to obtain the target element / isotope signal intensity.

[0112] The detection unit receives secondary ions generated by sputtering. By detecting and processing these secondary ions carrying sample composition information, a mass spectrometry image reflecting the elemental distribution on the sample surface is generated. This realizes a complete mass spectrometry imaging process from ion beam emission and modulation to signal detection. It should be noted that the above process describes only one mass spectrometry procedure. After the detection unit receives the sputtered secondary ions and generates the mass spectrometry image, a new target area different from the previous bombardment area can be determined according to the detection requirements, and the above process can be repeated for ion mass spectrometry analysis.

[0113] Furthermore, mass spectrometry imaging methods also include:

[0114] S201. Determine the maximum scanning area of ​​the mass spectrometry imaging device on the sample target surface;

[0115] Specifically, the steps for determining the maximum scanning area of ​​the mass spectrometry imaging device on the sample target surface include:

[0116] (1) Determine the initial scanning range based on the optical image and the target requirements;

[0117] (2) Determine the maximum and minimum values ​​of the directional voltage based on the scanning boundaries of the initial scanning range;

[0118] (3) The scanning area of ​​the mass spectrometry imaging device is obtained based on the maximum and minimum values ​​of the directional voltage;

[0119] Specifically, the maximum voltage range is determined by the optical image and the preset experimental requirements, and the scanning range is used to determine the maximum voltage range. Based on the ion beam displacement distance in the optical image, the directional voltage is continuously adjusted until the scanning boundary of the initial scanning range is reached. Then, the interleaving voltage is determined based on the voltage transformation coefficient. The directional voltage and interleaving voltage obtained at the scanning boundary of the initial scanning range are the maximum and minimum values. For example, in a target range of 50*50, assuming the center point coordinates are (0,0), then the voltage values ​​at +25 and -25 are the maximum and minimum values.

[0120] Furthermore, it is easy to see from the voltage relationship between the two deflection plates that |V2|>|V1|, and this always holds true since distances a, b, and c are all positive. In addition, the aperture of the ion lens is much larger than the diameter of the ion beam, and will not obstruct the ion beam's flight trajectory. In summary, the maximum range of the deflection plate voltages for the adjustable voltage can be considered as the maximum scannable region.

[0121] (4) The area after subtracting the beam diameter of the ion beam from the scanning area is taken as the maximum scanning area.

[0122] Specifically, to avoid the edge of the ion beam spot exceeding the effective analysis range, the distance by which the scanning area is reduced inward by the diameter of the ion beam spot is used as the boundary of the maximum scanning area. This determines the maximum scanning area and avoids invalid sampling caused by exceeding the physical capabilities of the device.

[0123] Furthermore, Figure 4 A schematic diagram illustrating the division of the maximum scan region, which is an exemplary embodiment of this application, is provided below. Figure 4 , Figure 4 The largest square area is the scanning area, and the circle represents the ion beam spot. Starting from the edge of the square, the diameter of the ion beam spot is reduced inward, and the side of the ion beam spot formed by multiple ion beam spots away from the edge of the square is taken as the outer edge of the maximum scanning range.

[0124] S202. Oversample the maximum scanning region to obtain a convolutional image with superimposed noise;

[0125] Specifically, within the maximum scanning area, point-by-point scanning is performed with a step size higher than the conventional sampling density, recording the ion signal intensity at each sampling point to form an original signal matrix. The original signal naturally has noise superimposed due to factors such as ion statistical fluctuations and device electronic noise, and is affected by the ion beam point spread function, resulting in a convolution effect, ultimately generating a convolutional image.

[0126] Specifically, by increasing the sampling density, we can ensure that no microscopic compositional changes on the sample surface are missed: high-density sampling can capture more detailed information, retain sufficient original data for subsequent deconvolution processing, record the ion signal intensity through the detector, and map the spatial location to the signal value to obtain the original data for image reconstruction; noise mainly comes from the Poisson statistical characteristics of ion emission and the thermal noise of electronic components, while the convolution effect is caused by the spatial distribution of the ion beam spot.

[0127] Oversampling enhances image detail preservation by increasing the amount of data, providing a rich information base for subsequent numerical processing even with noise and convolution effects. While superimposed noise and convolution effects distort the image, they can be restored using mathematical algorithms, helping to improve the accuracy of the final sampling point localization.

[0128] For example, in one embodiment, the diameter D of the ion beam spot is adjusted, and each spot overlaps three times Δ=3 in both the x and y directions (taking a step size of D / 3 as an example). The maximum scanning area is scanned point by point with a step size of D / 3, using an S-shaped scanning trajectory. The scanning trajectory can be set in the host computer software. By scanning the maximum scanning area with a step size of D / 3, and preprocessing the secondary ion signals detected by the detector, a convolutional image with a certain degree of Poisson and Gaussian noise is obtained.

[0129] S203. Perform numerical processing on the convolutional image to obtain a mass spectrum image;

[0130] Specifically, the convolutional image can be numerically processed through the following steps:

[0131] (1) Obtain the point spread function (PSF);

[0132] Specifically, the beam spot generated by the system is considered to be a perfectly circular beam spot with uniform energy distribution, and its diameter is consistent with the actual beam spot diameter. In addition, the area of ​​each pixel block needs to be determined. The pixel block is square, and its side length is equal to the diameter of the circular beam spot divided by the number of overlaps (i.e., the number of oversampling times). The circular beam spot is divided into blocks by the pixel blocks. Since the beam spot is uniformly distributed, the ratio of the area covered by the beam spot in each pixel block can be used as an approximation of the energy ratio in the point spread function (PSF), thus obtaining the PSF.

[0133] For example, in one embodiment, the overlap number is 3 and the beam spot diameter is D. Therefore, the side length of the pixel block is D / 3. In this case, the center of the beam spot corresponds to the center of the central pixel, and it should exactly cover 3*3 pixel blocks. Since the energy distribution is uniform, the area can represent the signal strength. The energy ratio of the nine pixel blocks can be obtained based on the ratio of the areas covered by each pixel block. These nine pixel blocks with different energy ratios are the point spread function (PSF) when the overlap number is 3.

[0134] Furthermore, the steps for obtaining the point spread function (PSF) include: placing the sample in a pre-arranged optical system, adjusting the optical path to make the point light source clearly imaged on the sample surface, acquiring the original image of the point light source using a detector, performing preprocessing on the original image to remove background noise and correct system distortion, locating the central region in the preprocessed original image using the centroid method or peak detection, and using the light intensity distribution of the central region as the point spread function (PSF).

[0135] (2) The convolutional image is deconvolved using the point spread function PSF to obtain a deconvolutional image.

[0136] Specifically, since the oversampling process yields a convolutional image with a certain degree of Poisson and Gaussian noise, rather than the true distribution of analyte concentration, it needs to be processed through deconvolution. The point spread function (PSF) is used to deconvolve the convolutional image. After deconvolution, the total integral of the scanned region is adjusted, and the signal intensity is recalculated. This recalculated mass spectrometry image is considered to represent the true distribution of analyte concentration.

[0137] Furthermore, the steps for determining the optimal sampling point based on the numerical processing results include:

[0138] (1) Obtain the coordinates and relative intensity values ​​of each pixel block in the deconvolution image;

[0139] (2) Calculate the sum of the relative intensity values ​​of all pixel blocks within the ion beam coverage area, and take the coverage area with the largest sum as the target area;

[0140] (3) Determine the center pixel block in the target area and use the center pixel block as the optimal sampling point.

[0141] Specifically, the numerically processed convolutional image refers to the real image obtained after operations such as deconvolution and counting integration adjustment. The coordinates of each pixel block correspond to the physical position on the sample target surface, and the relative intensity value reflects the concentration characteristics of the analyte at that position.

[0142] The ion beam coverage area refers to the spatial range of the actual effect of the beam spot when the ion beam bombards the sample target surface. For each coverage area, the relative intensity values ​​of all the pixels it contains are summed. The sum value reflects the total concentration of the analyte in that coverage area; the larger the sum value, the more enriched the target component is in that coverage area. All coverage areas are sorted according to the sum value, and the coverage area with the largest sum value is selected as the target area.

[0143] Furthermore, the central pixel block is the pixel corresponding to the geometric center of the target area. Selecting the central pixel block as the optimal sampling point can ensure that the ion beam bombardment position coincides with the high-concentration center of the target area, reduce errors caused by beam spot edge effects, and improve sampling accuracy.

[0144] S204. Determine the optimal sampling point of the mass spectrometry image based on the numerical processing results, and perform single-point elemental analysis based on the optimal sampling point.

[0145] Specifically, after oversampling to obtain a convolutional image and then deconvolution to obtain the true image, mass spectrometry imaging is achieved, and the optimal sampling point is determined. Single-point analysis is then performed on the optimal sampling point, which, as the analysis effect is best within the region. The control and adjustment channel precisely guides the ion beam to the optimal sampling point. The ion beam bombards this point, generating secondary ions. The detection unit receives and records the secondary ion signals, and mass-to-charge ratio analysis and intensity quantification are performed on the secondary ion signals to generate the compositional data for that point. Targeted imaging of the optimal sampling point avoids information redundancy from indiscriminate scanning, focusing on the most valuable region and significantly improving analysis efficiency. Combined with the device's precise control capabilities, high signal-to-noise ratio mass spectrometry data can be stably acquired, providing reliable experimental evidence for subsequent material composition analysis and structural studies.

[0146] The mass spectrometry imaging method provided in this embodiment determines the initial scanning range based on optical images and target requirements. It then determines the corresponding extreme values ​​of the directional voltage based on the boundaries of the initial scanning range, and combines this with beam spot diameter correction boundaries. This ensures that the sampling range does not exceed the physical control capabilities of the device while preventing the beam spot edges from exceeding the effective analysis area, thus defining reliable physical boundaries for subsequent sampling. Oversampling is performed on the maximum scanning region to obtain a convolutional image with superimposed noise at a higher density than usual. By increasing the data volume, more detailed information about the microscopic compositional changes of the sample is preserved, providing a rich raw data foundation for subsequent numerical processing. Further numerical processing is performed on the convolutional image, and the sample concentration distribution is obtained through deconvolution. Based on the concentration distribution, the relative intensity and value of each ion beam coverage area are calculated. The region with the largest sum is selected, and its central pixel block is used as the optimal sampling point. Sampling is then performed on the optimal sampling point. This method ensures that the sampling point is located in the high-concentration core region, avoids errors caused by beam spot edge effects, eliminates reliance on human experience, achieves precise positioning of the sampling point, enables targeted imaging of the optimal sampling point, focuses on the region with the highest sample concentration, improves the relevance and analysis efficiency of mass spectrometry images, reduces information redundancy, and provides reliable support for the accurate analysis of the microscopic components of the sample.

[0147] The method in this embodiment can be used to execute Figure 1 The steps of the device embodiment shown are similar in principle and process, and will not be repeated here.

[0148] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A mass spectrometry imaging device, characterized in that, The device includes: The emission unit is used to emit an ion beam toward the sample target; The adjustment channel is used to adjust the flight direction and vertical offset of the ion beam emitted by the emission unit, so that the beam spot shape after the ion beam flies at different angles and is focused by the ion lens is the same as when it flies along the optical axis, and bombards the target area of ​​the sample target. The adjustment channel is provided with multiple deflection plate groups, each deflection plate group includes four deflection plates of the same size and arranged opposite each other, and the multiple deflection plate groups are arranged horizontally; each deflection plate group is connected to an adjustable voltage signal, the amplitude of the adjustable voltage signal is related to the target flight direction of the ion beam, the size of the deflection plate, and the arrangement position of each deflection plate group in the adjustment channel through which the ion beam passes; The inlet of the adjustment channel is connected to the emission unit, and the outlet of the adjustment channel is provided with an ion lens. The device also includes a voltage adjustment unit, which is connected to each deflection plate group. The voltage adjustment unit is used to calculate the adjustment voltage based on the direction requirement of the ion beam bombarding the sample target, calculate the adjustment distance voltage based on the adjustment voltage, set the voltage of the N deflection plate groups farthest from the ion lens as the adjustment voltage, and set the voltage of the M deflection plate groups closest to the ion lens as the adjustment distance voltage; control the flight direction of the ion beam according to the adjustment voltage, and control the vertical offset of the adjusted ion beam according to the adjustment distance voltage, so that the displacement of the adjusted ion beam perpendicular to the emission direction is zero compared with the ion beam before adjustment. A detection unit is used to receive secondary ions generated after the ion beam passes through the adjustment channel and bombards the surface of the sample target.

2. The apparatus according to claim 1, characterized in that, The calculation of the directional voltage based on the direction requirement of the ion beam bombarding the sample target includes: The incident angle of the ion beam onto the ion lens is determined according to the stated direction requirements; The directional voltage is determined based on the incident angle.

3. The apparatus according to claim 1, characterized in that, The calculation of the adjustment voltage based on the directional voltage includes: Obtain the dimension information of each deflection plate; Determine the relative positional relationship between adjacent deflector plate groups; Determine the minimum distance between the plurality of deflection plate groups and the ion lens; The voltage transformation coefficient is calculated based on the size information, relative positional relationship, and minimum spacing. The adjustment voltage is calculated based on the product of the voltage transformation coefficient and the adjustment voltage.

4. The apparatus according to claim 1, characterized in that, The device also includes an optical imaging module for optical imaging of the sample target. The device is also used to determine the core deflection plate group based on the voltage relationship between multiple deflection plate groups, and to determine the target area based on the optical image and the scanning range of the core deflection plate.

5. A mass spectrometry imaging method, characterized in that, The method is implemented based on the apparatus according to any one of claims 1-4, and the method includes: The emission unit emits a single ion beam toward the sample target surface; Adjust the channel to adjust the flight direction and vertical offset of the primary ion beam, and sputter secondary ions; The detection unit receives the sputtered secondary ions and obtains a mass spectrum image.

6. The method according to claim 5, characterized in that, The method further includes: Determine the maximum scanning area of ​​the mass spectrometry imaging device on the sample target surface; Oversampling is performed on the maximum scanning region to obtain a convolutional image with superimposed noise; Numerical processing is performed on the convolutional image to obtain a mass spectrum image; The optimal sampling point of the mass spectrometry image is determined based on the numerical processing results, and single-point elemental analysis is performed based on the optimal sampling point.

7. The method according to claim 6, characterized in that, Determining the maximum scanning area of ​​the mass spectrometry imaging device on the sample target surface includes: Determine the initial scanning range based on the optical image and the target requirements; The maximum and minimum values ​​of the directional voltage are determined based on the scan boundaries of the initial scan range; The scanning area of ​​the mass spectrometry imaging device is obtained based on the maximum and minimum values ​​of the switching voltage; The maximum scanning area is the region obtained by subtracting the beam diameter of the ion beam from the scanning area inward.

8. The method according to claim 6, characterized in that, The numerical processing of the convolutional image includes: Obtain the point spread function (PSF); The convolutional image is deconvolved using the point spread function (PSF) to obtain a deconvolutional image.

9. The method according to claim 6, characterized in that, The numerical processing result is a concentration distribution image, and the determination of the optimal sampling point based on the numerical processing result includes: Obtain the coordinates and relative intensity values ​​of each pixel block in the deconvolutioned image; Calculate the sum of the relative intensity values ​​of all pixel blocks within the ion beam coverage area, and take the coverage area with the largest sum as the target area; Determine the center pixel block in the target region and use the center pixel block as the optimal sampling point.

Images