Double-source excitation EDXRF analysis instrument based on spectrum partitioning

Abstract

The invention discloses a double-source excitation EDXRF analysis instrument based on spectrum zoning, and belongs to the technical field of analysis and detection instruments, the double-source excitation EDXRF analysis instrument comprises a vacuum measurement chamber formed by a sealed shell, a vacuum system, a sample carrying table, a detection unit, double excitation sources and a control processing module, the first excitation source is a rhodium target X-ray tube and is adaptive to light element excitation, and the second excitation source is a rhodium target X-ray tube and is adaptive to light element excitation; a second excitation source is a tungsten target X-ray tube, is adaptive to medium and heavy element excitation, is provided with an aluminum-copper composite optical filter, adopts a compact layout of double units, is matched with a circulating water cooling system and a graphene window SDD detector, and is matched with a spectrum partition design to physically separate double-source signals and a low-vacuum environment to guarantee light element transmission; the instrument solves the problem that a traditional single source cannot give consideration to full-spectrum excitation and spectrum overlapping interference, realizes high-sensitivity and high-signal-to-noise-ratio measurement of all elements from sodium to uranium, supports synchronization and time sequence dual modes, and improves the detection efficiency and precision.

Description

Technical Field

[0001] This invention belongs to the technical field of analytical instruments, specifically relating to a dual-source excitation EDXRF analyzer based on spectral partitioning. Background Technology

[0002] Dual-source excitation EDXRF analyzers are analytical devices that utilize dual X-ray excitation sources combined with energy-dispersive X-ray fluorescence spectroscopy to detect the elemental composition and content of substances. Due to their non-destructive and rapid characteristics, they are widely used in materials science, environmental monitoring, geological exploration and other fields.

[0003] However, existing traditional single-source EDXRF cannot simultaneously excite light and medium-heavy elements. When optimizing light elements with low voltage, it cannot excite heavy elements. When exciting heavy elements with high voltage, it will generate high-energy background interference with the detection of light elements. The characteristic X-rays of light elements have low energy and are easily absorbed by air and traditional window materials, resulting in insufficient detection sensitivity. Dual-source designs are mostly homogeneous architectures, lack effective spectral separation methods, and are prone to signal overlap. Furthermore, heat dissipation of the X-ray tube is difficult in a vacuum environment, affecting long-term operational stability. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-source excitation EDXRF analyzer based on spectral partitioning, in order to solve the problems mentioned in the background art, such as the inability of existing instruments to simultaneously excite the full spectrum of elements, severe spectral overlap and interference, light element detection being affected by air and window absorption, and poor heat dissipation and insufficient stability in a vacuum environment.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a dual-source excitation EDXRF analyzer based on spectral partitioning, comprising a vacuum cabinet, wherein a vacuum-electrifiable measurement chamber is formed inside the vacuum cabinet, the inner wall of the chamber is lined with a low atomic number material, the measurement chamber is connected to a vacuum system, and a sample stage, a rotating stage and a detection unit are arranged inside the chamber sample, the detection unit including a high count rate SDD detector, the instrument also comprising a first excitation source, a second excitation source and a control and processing module, the control and processing module being electrically connected to each unit respectively.

[0006] Preferably, the first excitation source includes a first excitation source and a first brass collimator. The first excitation source is a rhodium target or scandium target X-ray tube equipped with an ultrathin polymer window or graphene window. There is no filter in the optical path. The first excitation source operates in a low voltage mode of 5-8kV and a high current mode of 800-1000μA.

[0007] Preferably, the second excitation source includes a second excitation source, a second brass collimator, and a filter. The second excitation source is a tungsten target or a gold target X-ray tube, operating in a 40-50kV high-voltage mode. The filter is an aluminum-copper composite filter used to absorb X-ray photons below 10keV.

[0008] Preferably, the vacuum system includes a vacuum gauge, a vacuum pipeline, and a rotary vane pump. The vacuum pipeline connects the vacuum cabinet and the rotary vane pump. The vacuum system can regulate the air pressure inside the chamber to below 10 Pa.

[0009] Preferably, the SDD detector is equipped with a graphene incident window, an output count rate greater than 300 kcps, and an energy resolution better than 125 eV (@MnKα).

[0010] Preferably, both the first and second excitation sources are equipped with cooling circuits, which include circulating water inlet pipes and circulating water outlet pipes, and are connected to an external circulating water chiller to form a closed-loop heat dissipation system.

[0011] Preferably, the sample stage is connected to the rotary stage, which is driven by a rotary motor. The first and second excitation sources are mounted on an integrated support, and a compact direct excitation geometry is adopted.

[0012] Compared with existing technologies, this invention provides a dual-source excitation EDXRF analyzer based on spectral partitioning, which has the following advantages: By setting up a first excitation source, a second excitation source, a low-energy cutoff filter, an ultra-thin window, and a composite filter, the system achieves precise excitation of all elements and spectral partitioning. The first unit's low-voltage, high-current mode is adapted to light elements, while the second unit's high-voltage mode, combined with the composite filter, is adapted to medium and heavy elements. This physically cuts off low-energy interference, solves the problems of spectral overlap and full-spectrum excitation, and improves the detection sensitivity and signal-to-noise ratio of each element.

[0013] By incorporating a vacuum system, a circulating water chiller, a cooling circuit, and a graphene window detector, the system ensures detection stability and light element detection effectiveness. The low vacuum environment reduces the absorption of light element rays by the air, the circulating water cooling system solves the heat dissipation problem under vacuum, and the graphene window improves the transmittance of low-energy photons. This addresses the issues of insufficient light element detection and long-term instability in existing instruments, and supports dual-mode measurement to improve detection efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the structure of the excitation unit and the detection unit in this invention.

[0016] Figure 3 This is a schematic diagram of the excitation source in this invention.

[0017] Figure 4 This is a schematic diagram of the rotary vane pump in this invention.

[0018] Figure 5 This is a schematic diagram of the spectrum in this invention.

[0019] In the diagram: 1. Circulating water chiller; 2. Circulating water inlet pipe; 3. SDD detector; 4. Circulating water outlet pipe; 5. Second excitation source; 6. Integrated support; 7. Sample stage; 8. Rotary motor; 9. First excitation source; 10. Vacuum gauge; 11. Vacuum cabinet; 12. Vacuum pipe; 13. Rotary vane pump; 14. First brass collimator; 15. Second brass collimator; 16. Filter; 17. Sample; 18. Rotary stage; 19. Cathode end cap flange; 20. Cathode end cap; 21. Filament holder; 22. Small seat; 23. Window flange; 24. Anode end cap flange. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In this embodiment, the specific implementation steps of a dual-source excitation EDXRF analyzer based on spectral partitioning are as follows: The sample 17 to be tested is placed on the sample stage 7 and the rotating stage 18. The door of the sealed housing 11 is closed. The rotary vane pump 13 is started, and the measurement chamber is evacuated through the vacuum pipe 12. The vacuum gauge 10 is observed until the air pressure in the chamber drops below 10 Pa, thus establishing a low-vacuum environment. The measurement mode is selected through the control and processing module. In the sequential mode, the first excitation source is activated first, followed by the second excitation source. In the synchronous mode, both excitation sources are activated simultaneously. The first X-ray tube 9 of the first excitation source operates in a low-voltage (5-8 kV) and high-current (800-1000 μA) mode, passing through the first brass... Collimator 14 emits low-energy rays to excite the light elements in the sample. The second X-ray tube 5 of the second excitation source operates in a 40-50kV high-voltage mode. After being filtered by the second brass collimator 15 and filter 16, it emits high-energy rays to excite the heavy elements in the sample. SDD detector 3 collects the fluorescence spectrum generated by the sample after excitation and transmits it to the control and processing module. The control and processing module processes the spectral data through a dual-source spectral decomposition algorithm or blind source separation technology, separates overlapping backgrounds, calculates the content of each element, and finally outputs an analysis report containing all elements from sodium to uranium. After the measurement is completed, the dual excitation sources are turned off, the rotary vane pump 13 is stopped, and after the measurement chamber returns to normal pressure, the sample 17 is taken out and the circulating water chiller 1 is turned off.

[0022] like Figure 1-5As shown, the first excitation source includes a first excitation source 9 and a first brass collimator 14. The first excitation source 9 is a rhodium target X-ray tube equipped with an ultrathin polymer window or graphene window, and there is no filter in the optical path. The second excitation source includes a second excitation source 5, a second brass collimator 15, and a filter 16. The second excitation source 5 is a tungsten target X-ray tube, and the filter 16 is a composite filter composed of 200-500μm aluminum and 50-100μm copper. The first and second excitation sources are mounted on an integrated bracket 6 and adopt a compact direct excitation geometry layout.

[0023] Preferably, the first brass collimator 14 is lined with pure silver and has an aperture of 2mm to maximize the low-energy photon flux. The second brass collimator 15 is integrated with the filter 16 to ensure stable filtering effect. The rays from the dual excitation sources and the receiving field of view of the SDD detector 3 are precisely confocal at the same point on the surface of the sample 17 to eliminate parallax effect.

[0024] like Figure 1-2 and Figure 4 As shown, the vacuum system includes a vacuum gauge 10, a vacuum pipe 12, and a rotary vane pump 13. The vacuum pipe 12 connects the vacuum cabinet 11 and the rotary vane pump 13. The vacuum gauge 10 is used to monitor the air pressure inside the chamber. The circulating water chiller 1 is connected to the cooling circuit of the dual excitation source through the circulating water inlet pipe 2 and the circulating water outlet pipe 4.

[0025] Preferably, the rotary vane pump 13 has a fast vacuuming rate, which can quickly reduce the chamber pressure to below 10Pa. The circulating water inlet pipe 2 and the circulating water outlet pipe 4 adopt a sealed design to prevent vacuum leakage. The cooling circuit adopts an oxygen-free copper conductive cooling module, which has high heat dissipation efficiency and ensures long-term stable operation of the X-ray tube.

[0026] like Figure 1-3 As shown, the SDD detector 3 is equipped with a graphene incident window, the sample stage 7 is connected to the rotary stage 18, the rotary motor 8 drives the rotary stage 18 to rotate, the inner wall of the vacuum cabinet 11 is lined with high-purity aluminum or polytetrafluoroethylene material, and the front and rear sides of the emission source include a cathode end cover flange 19, a cathode end cover 20, a filament holder 21, a small seat 22, a window flange 23, and an anode end cover flange 24.

[0027] Optionally, the SDD detector 3 has an output count rate greater than 300 kcps, an energy resolution better than 125 eV (@MnKα), and a stacking rejection function. The rotary stage 18 can rotate 360 ​​degrees to eliminate the influence of sample inhomogeneity on the measurement results. Each flange interface uses a sealing gasket to ensure the vacuum sealing of the measurement chamber.

[0028] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-source excitation EDXRF analyzer based on spectral partitioning, comprising a vacuum cabinet (11), characterized in that: The vacuum cabinet (11) forms a vacuum measurement chamber inside, the inner wall of which is lined with a low atomic number material. The measurement chamber is connected to a vacuum system. The chamber is equipped with a sample stage (7), a rotating stage (18), and a detection unit. The detection unit includes a high count rate SDD detector (3). The instrument is also equipped with a first excitation source, a second excitation source, and a control and processing module. The control and processing module is electrically connected to each unit.

2. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 1, characterized in that: The first excitation source includes a first excitation source (9) and a first brass collimator (14). The first excitation source (9) is a rhodium target or scandium target X-ray tube equipped with an ultra-thin polymer window or graphene window. There is no filter in the optical path. The first excitation source (9) operates in a low voltage mode of 5-8kV and a high current mode of 800-1000μA.

3. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 2, characterized in that: The second excitation source includes a second excitation source (5), a second brass collimator (15), and a filter (16). The second excitation source (5) is a tungsten target or gold target X-ray tube, which operates in a 40-50kV high voltage mode. The filter (16) is an aluminum-copper composite filter used to absorb X-ray photons below 10keV.

4. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 3, characterized in that: The vacuum system includes a vacuum gauge (10), a vacuum pipe (12) and a rotary vane pump (13). The vacuum pipe (12) connects the vacuum cabinet (11) and the rotary vane pump (13). The vacuum system can adjust the air pressure in the chamber to below 10 Pa.

5. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 1, characterized in that: The SDD detector (3) is equipped with a graphene incident window, with an output count rate greater than 300 kcps and an energy resolution better than 125 eV (@MnKα).

6. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 1, characterized in that: Both the first and second excitation sources are equipped with cooling circuits, which include a circulating water inlet pipe (2) and a circulating water outlet pipe (4), and are connected to an external circulating water chiller (1) to form a closed-loop heat dissipation system.

7. A dual-source excitation EDXRF analyzer based on spectral partitioning according to claim 1, characterized in that: The sample stage (7) is connected to the rotary stage (18), which is driven by a rotary motor (8). The first and second excitation sources are mounted on the integrated bracket (6) and adopt a compact direct excitation geometry.

8. A measurement method based on the spectrometer according to any one of claims 1-7, characterized in that, The process includes the following steps: S1 Environment Setup: Start the vacuum system to reduce the pressure in the measurement chamber to below 10 Pa to ensure that the transmittance of the NaKα line is greater than 90%; S2 Spectral Zone Excitation: Mode A (Time-sequential measurement): First, turn on the first excitation source (9) and collect only the low-energy spectrum of 0-5keV; then turn on the second excitation source (5) and collect only the high-energy spectrum of 5-50keV; Mode B (Synchronous measurement): Turn on the first excitation source (9) and the second excitation source (5) at the same time, and use the low-energy cutoff filter (16) to prevent the high-energy electrons and scattered rays of the second excitation source from interfering with the low-energy region, and obtain the full spectrum in a single exposure; S3 Data Processing: Using dual-source spectral decomposition algorithms or blind source separation (BSS) technology, overlapping backgrounds are separated, and elemental contents are calculated for different energy ranges.

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