Laser ablation detection device based on flat-topped light beam

Abstract

The utility model discloses a laser ablation detection device based on a flat-topped light beam. The laser ablation detection device comprises a laser ablation module, a sample pool module and a mass spectrum detection module, the laser ablation module comprises a laser emitter, a flat-topped light beam generation module, a galvanometer module and a sample lens which are connected in sequence; the laser ablation module is in light path connection with the sample pool module; and the sample pool module is connected with the mass spectrum detection module through a gas circuit. According to the denudation laser, Gaussian beams with non-uniform energy are converted into flat-topped beams with flat and uniform energy distribution curves through the flat-topped beam generator, the flat-topped beams act on the surface of a sample, and a denudated sample pit is changed into a flat-bottom pit with a sharp edge from a traditional conical pit. The denudation uniformity and the denudated sample amount consistency can be improved, and the reliability, the sensitivity and the accuracy of an LA-ICP-MS system are effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of laser ablation, and in particular relates to a laser ablation detection device based on a flat-top light beam. Background Art

[0002] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a solid direct sampling, in-situ, micro-area, elemental analysis technology. With the gradual maturity of laser ablation systems, LA-ICP-MS has been widely used in geology, environment, archaeology, materials and other fields. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) uses a laser to emit a laser beam, uses an objective lens to focus the laser on a specific area of ​​the sample, and uses the energy of the pulsed laser to directly ablate the solid sample into tiny particles, forming an aerosol with the carrier gas, and then the particles are plasmatized by an inductively coupled plasma source (ICP) and enter the mass spectrometer for element detection.

[0003] In some test scenarios that require deeper erosion depth and more uniform erosion effect, relying solely on existing laser emitters cannot effectively meet the requirements. Utility Model Content

[0004] In view of this, an object of the present invention is to provide a laser ablation detection device based on a flat-top light beam to solve the problems raised in the background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides a laser ablation detection device based on a flat-top light beam, characterized in that it includes a laser ablation module, a sample pool module and a mass spectrometry detection module;

[0006] The laser ablation module comprises a laser emitter, a flat-top light beam generating module, a galvanometer module and a sample lens which are connected in sequence;

[0007] The sample pool module is gas-circuit connected to the mass spectrometry detection module.

[0008] Preferably, the sample pool module comprises a housing, a sample air inlet, a sample air outlet, a sample cup, a sample holder, and a sample moving platform;

[0009] The sample air inlet and the sample air outlet are arranged on the housing;

[0010] The sample moving stage is arranged in the housing;

[0011] The sample holder is arranged above the sample moving platform;

[0012] The sample cup is arranged on a sample support.

[0013] Preferably, the sample pool module further comprises an oxygen sensor, which is disposed outside the housing and connected to the gas path of the sample gas outlet.

[0014] Preferably, the sample moving stage is a three-axis moving stage.

[0015] Preferably, the galvanometer module is a three-dimensional galvanometer module, and the three-dimensional galvanometer module includes a Z-axis moving lens, a Z-axis focusing lens, an X-axis galvanometer and a Y-axis galvanometer;

[0016] The three-dimensional galvanometer module adjusts the position of the focus of the ablation laser along the optical axis at high speed through the cooperation of the Z-axis moving lens and the Z-axis focusing lens; the X-axis galvanometer and the Y-axis galvanometer are used to adjust the position of the focus of the ablation laser along the direction perpendicular to the optical axis at high speed.

[0017] Preferably, the laser ablation module further comprises an optical observation module, and the optical observation module is used to observe the sample and generate a sample photo, and the sample photo is used to determine the sample ablation area.

[0018] The beneficial effects of the utility model are:

[0019] The ablation laser of the utility model converts a Gaussian beam with uneven energy into a flat-top beam with a smooth and uniform energy distribution curve through a flat-top beam generator. The flat-top beam acts on the sample surface, and changes the ablated sample pit from a traditional conical pit into a flat-bottom pit with a sharp edge, which can improve the uniformity of ablation and the consistency of the amount of ablated sample, and effectively improve the reliability, sensitivity and accuracy of the LA-ICP-MS system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a structural schematic diagram of a laser ablation detection device based on a flat-top light beam disclosed in the utility model;

[0022] Figure 2 It is a structural schematic diagram of the three-dimensional galvanometer module disclosed in the utility model; DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] like Figure 1 As shown, a laser ablation detection device based on a flat-top light beam disclosed in this embodiment includes a laser ablation module 10, a sample pool module 20 and a mass spectrometer detection module 30. The laser ablation module 10 includes a laser emitter 11, a flat-top light beam generating module 16, a galvanometer module 13 and a sample lens 14 connected in sequence. The laser emitter is used to generate an ablation laser 12. The flat-top light beam generating module 16 is used to form the ablation laser 12 into a flat-top light beam. The flat-top light beam passes through the galvanometer module and is imaged onto the sample. The galvanometer module 13 is used to adjust the focus position of the ablation laser at high speed. The sample lens 14 is an objective lens. Those skilled in the art can also replace the objective lens with a field lens according to actual needs to achieve laser ablation with a larger range and a larger depth of field. The laser ablation module 10 is optically connected to the sample pool module 20. The sample pool module 20 is connected to the mass spectrometer detection module 30 through the homogenization tube 40; the sample 15 and the standard sample particles removed by the laser are mixed with the carrier gas to form an aerosol. After the aerosol is homogenized by the homogenization tube 40, it enters the mass spectrometer detection module 30 through the gas path for element content analysis. The homogenization tube 40 can fully mix the sample aerosol and significantly improve the mass spectrometer signal. Compared with the traditional Gaussian beam, the flat-top beam is a laser beam or electron beam with almost uniform flux (energy density) in a circular area. Therefore, the flat-top light beam of this embodiment acts on the sample surface more uniformly than Gaussian light, and the ablation effect is better, which can improve the ablation depth and uniformity, and effectively improve the reliability, sensitivity and accuracy of the LA-ICP-MS system.

[0025] In this embodiment, the laser emitter 11 is a femtosecond laser, which realizes high-frequency laser ablation (up to more than 10,000 Hz). In addition, through the optimization of the optical path, the energy of each pulse is stable, which can ensure that regular flat-bottomed pits are produced and the weight of the ablated sample aerosol particles is stable.

[0026] In this embodiment, the mass spectrometry detection module 30 may be a mass spectrometry analysis instrument such as ICP-MS or ICP-TOF-MS.

[0027] In this embodiment, the sample pool module 20 includes a housing 24, a sample air inlet 25, a sample air outlet 26, a sample cup 21, a sample holder 22, a sample moving platform 23, a vacuum pump 27 and an oxygen sensor 28; the sample air inlet 25 and the sample air outlet 26 are arranged on both sides of the housing; the sample moving platform is arranged in the housing 24; the sample holder 22 is arranged above the sample moving platform 23; and the sample cup 21 is arranged on the sample holder 22. In this embodiment, there are two sample air inlets 25, which are respectively used to introduce carrier gas and protective gas. In other embodiments, the number of sample air inlets 25 can be set as needed, which is not limited here. In this embodiment, there are two sample air outlets 26, one of which is connected to the homogenization tube 40, and the aerosol particles are transmitted to the ICP-MS for analysis through the homogenization tube 40, and the other is connected to the vacuum pump 27, which is used to subsequently empty the gas in the sample pool module 20. The sample air outlet 26 connected to the vacuum pump 27 should be in a sealed / closed state during laser ablation. In some other embodiments, a sample outlet 26 is provided and connected to an oxygen sensor 28. The oxygen sensor 28 is used to monitor the oxygen content in the sample pool module 20 at any time. One purpose is to ensure the gas atmosphere during laser ablation. Another purpose is to ensure that the ICP-MS mass spectrometer will not shut down due to excessive oxygen content during sample testing. Another purpose is to ensure that the gas replacement is relatively thorough during gas replacement operations. For example, before sample testing, replacing the air with helium can ensure that the oxygen is completely discharged.

[0028] In this embodiment, if Figure 1 As shown, the laser ablation module also includes a coaxially arranged optical observation module 50, which is used to generate sample photos. A person skilled in the art can select the ablation area of ​​the sample to be tested and the standard sample on the sample photo through the operating software, and automatically generate the corresponding instrument parameters of the galvanometer module, thereby completing automatic ablation scanning of the sample to be tested and the standard sample.

[0029] In some other embodiments, such as Figure 2As shown, the galvanometer module is a three-dimensional galvanometer module, which includes a Z-axis moving lens 101, a Z-axis focusing lens 102, an X-axis galvanometer 103, and a Y-axis galvanometer 104; the three-dimensional galvanometer module adjusts the position of the focus of the ablation laser along the optical axis at high speed through the cooperation of the Z-axis moving lens 101 and the Z-axis focusing lens 102 (adjusting the distance between the Z-axis moving lens 101 and the Z-axis focusing lens 102); the X-axis galvanometer 103 and the Y-axis galvanometer 104 are used to adjust the position of the focus of the ablation laser along the direction perpendicular to the optical axis at high speed, and the X-axis galvanometer 103 and the Y-axis galvanometer 104 can respectively perform high-frequency reciprocating rotation around the axis. Through the high-speed rotation of the galvanometer motor of the three-dimensional galvanometer module, it is possible to switch back and forth between the sample to be tested and the standard sample at high speed in a very short time and perform multiple laser ablation (the number of times can be up to 1 million times, so that the quantitative addition result is more accurate), just like ablation of a sample.

[0030] The specific operation process of the detection device of this embodiment is as follows:

[0031] 1) Turn on the power of the computer and each subsystem, and preheat each subsystem;

[0032] 2) Open the sample cell door of the sample cell module 20, put the sample to be tested and the standard sample into the sample holder and fix them, install them on the three-axis precision moving table of the sample cell, and close the sample cell door.

[0033] 3) The sample cell module is fed with carrier gas and protective gas, mainly helium, but different gases can also be selected according to the main elements to be detected;

[0034] 4) Through the coaxial optical observation module 50, adjust the height of the three-axis precision moving stage in the sample pool module 20, focus, and take pictures of the sample to be tested and the standard sample;

[0035] 5) Import the photo and select the erosion area of ​​the sample to be tested and the standard sample on the photo;

[0036] 6) Perform software programming to set laser ablation parameters, ablation sequence of the sample to be tested and the standard sample, ablation frequency, etc.;

[0037] 7) The computer starts to control each subsystem to work according to the pre-set parameters;

[0038] 8) The ablation laser generated by the femtosecond laser forms a flat-top beam through a flat-top beam generation module, and then the flat-top beam passes through an optical path system and is focused on the ablation area of ​​the sample to be tested and the standard sample for ablation;

[0039] 9) The sample and standard particles removed by laser ablation are mixed with carrier gas to form an aerosol. After the aerosol is homogenized by a homogenizer, it enters the ICP-MS through the gas path for element content analysis;

[0040] 10) After the test is completed, open the sample pool door, take out the sample, store it in the designated area, and close the door;

[0041] 11) If all analysis tasks are completed, turn off the carrier gas and all subsystems;

[0042] 12) Use analysis software to process data and obtain sample content.

[0043] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0044] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser ablation detection device based on a flat-top light beam, characterized in that: It includes a laser ablation module, a sample pool module and a mass spectrometry detection module; The laser ablation module comprises a laser emitter, a flat-top light beam generating module, a galvanometer module and a sample lens which are connected in sequence; The laser ablation module is optically connected to the sample cell module; The sample pool module is gas-circuit connected to the mass spectrometry detection module.

2. The detection device according to claim 1, characterized in that: The sample pool module comprises a housing, a sample air inlet, a sample air outlet, a sample cup, a sample bracket, and a sample moving platform; The sample air inlet and the sample air outlet are arranged on the housing; The sample moving stage is arranged in the housing; The sample holder is arranged above the sample moving platform; The sample cup is arranged on a sample support.

3. The detection device according to claim 1, characterized in that: The sample pool module also includes an oxygen sensor, which is arranged outside the housing and connected to the gas path of the sample gas outlet.

4. The detection device according to claim 2, characterized in that: The sample moving stage is a three-axis moving stage.

5. The detection device according to claim 1, characterized in that: The galvanometer module is a three-dimensional galvanometer module, and the three-dimensional galvanometer module includes a Z-axis moving lens, a Z-axis focusing lens, an X-axis galvanometer and a Y-axis galvanometer; The three-dimensional galvanometer module adjusts the position of the focus of the ablation laser along the optical axis at high speed through the cooperation of the Z-axis moving lens and the Z-axis focusing lens; the X-axis galvanometer and the Y-axis galvanometer are used to adjust the position of the focus of the ablation laser along the direction perpendicular to the optical axis at high speed.

6. The detection device according to claim 1, characterized in that: The laser ablation module further comprises an optical observation module, wherein the optical observation module is used to generate sample photos, and the sample photos are used to determine the sample ablation area.

7. The detection device according to claim 1, characterized in that: The sample pool module is connected to the mass spectrometry detection module through a homogenization tube.

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