In-situ soft X-ray fluorescence absorption spectrum acquisition system

Abstract

The invention relates to the technical field of soft X-ray measurement, in particular to an in-situ soft X-ray fluorescence absorption spectrum acquisition system. Comprising a synchrotron radiation light source, a beam line monochromator, a beam monitoring device and a sample table which are linearly arranged in sequence, synchrotron radiation light emitted by the synchrotron radiation light source is monochromatized by the beam line monochromator and then is projected to a sample at the sample table with specific energy; the beam monitoring device measures the intensity of synchrotron radiation beam flow in real time, generates a first current signal and feeds back the first current signal to the numerical control terminal; a fluorescence signal acquisition device is erected around the sample table, the fluorescence signal acquisition device is used for capturing a fluorescence signal dissipated after the sample is irradiated by the synchrotron radiation light, generating a second current signal and feeding back the second current signal to a numerical control terminal, and the numerical control terminal is configured to control the beam line monochromator to perform energy scanning on the sample. And the first current signal and the second current signal which are received in real time are synthesized to generate a soft X-ray fluorescence absorption spectrum result.

Description

Technical Field

[0001] The invention relates to the technical field of soft X-ray measurement, and in particular to an in-situ soft X-ray fluorescence absorption spectrum acquisition system. Background Art

[0002] Soft X-ray absorption spectroscopy is one of the effective means to characterize the electronic structure of materials. The principle is that when the sample is irradiated with X-rays, the inner electrons will absorb the corresponding energy and transition to an unoccupied state, while forming holes in the inner layer. The electrons in the unoccupied state will radiate energy outward in the form of excited Auger electrons or fluorescence. By measuring the fluorescence or electronic signal emitted by the sample, the absorption intensity of the material to X-rays can be measured, and then the electronic structure of the material can be analyzed. The soft X-ray energy range is about 50-2000eV, mainly covering the K absorption edge of light elements such as lithium, boron, carbon, nitrogen, and oxygen, as well as the L absorption edge of transition metals such as titanium, vanadium, chromium, and manganese. In recent years, it has been widely used in energy science, catalytic conversion, biomedicine, semiconductors and other fields, and has very important scientific significance.

[0003] The detection methods of soft X-ray absorption spectrum mainly include full electron yield mode, Auger electron yield mode, and full fluorescence yield mode. Among them, the Auger electron yield mode collects Auger electrons through an electron energy analyzer to obtain absorption signals; the full electron yield mode measures the sample photocurrent through an electrometer to obtain the signals of all emitted electrons of the sample. However, due to the limited escape depth of the emitted electrons, the detection depth of the above two detection modes is only a dozen nanometers, and neither can provide bulk phase information of the sample material. In addition, the detection depth of more than a dozen nanometers also affects the development of in-situ devices, making it difficult to assist scientific researchers in conducting in-situ experiments to understand the electronic structure evolution of the material under in-situ conditions.

[0004] At present, domestic soft X-ray absorption spectrum detection is still mainly based on the traditional full electron yield mode. Its limited detection depth completely restricts scientific researchers' exploration of the electronic structure of sample materials and in-situ experiments.

[0005] Therefore, it is of great significance to develop an in-situ soft X-ray fluorescence absorption spectrum acquisition system. Summary of the invention

[0006] The present invention provides an in-situ soft X-ray fluorescence absorption spectrum acquisition system, which broadens the detection depth of the soft X-ray absorption spectrum and can perform in-situ experiments, and can better help scientific research users analyze the electronic structure state of the material phase and the electronic structure evolution of the material under in-situ conditions. The specific technical solutions adopted are as follows: The present invention provides an in-situ soft X-ray fluorescence absorption spectrum acquisition system, comprising: a synchrotron radiation light source, a beam line monochromator, a beam current monitoring device and a sample stage which are linearly arranged in sequence; The synchrotron radiation light emitted by the synchrotron radiation source is monochromatized by the beam line monochromator and then projected onto the sample at the sample stage with a specific energy; the beam current monitoring device measures the synchrotron radiation beam current intensity in real time and generates a first current signal to feed back to the numerical control terminal; A fluorescence signal collection device is arranged around the sample stage, and the fluorescence signal collection device is used to capture the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation, and generate a second current signal to feed back to the numerical control terminal; A control circuit, the control circuit is used to provide the operating voltage required for the normal operation of the fluorescence signal acquisition device and has an overvoltage protection function; The monochromatization process of the synchrotron radiation light, the beam intensity detection process, the sample irradiation process and the fluorescence signal capture process are all carried out in a vacuum environment provided by a vacuum device; The numerical control terminal is configured to control the beam line monochromator to perform energy scanning on the sample, and to generate a soft X-ray fluorescence absorption spectrum result by integrating the first current signal and the second current signal received in real time.

[0007] Furthermore, an in-situ illumination device is set up around the sample stage; the in-situ illumination device changes the illumination intensity under the control of the numerical control terminal to provide different illumination conditions for the sample; The sample stage is provided with a thermocouple and a heating resistor. The numerical control terminal controls the input voltage of the heating resistor through a wire to change the power of the heating resistor and provide different temperature conditions for the sample. The thermocouple feeds back the current temperature information of the heating resistor to the numerical control terminal in real time.

[0008] Furthermore, the fluorescence signal collection device comprises: a signal collection end and a vacuum feedthrough; the signal collection end is fixedly connected to the vacuum feedthrough, and the vacuum feedthrough is fixedly installed on the side wall of the vacuum device through a flange port; The signal collecting end captures and collects the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation to generate a second current signal and transfers it to the vacuum feedthrough; the vacuum feedthrough feeds back the second current signal to the numerical control terminal through a wire.

[0009] Further, the signal collection end includes a coaxially mounted gold mesh assembly, a channel electron multiplier tube assembly and a supporting component; The gold mesh assembly is used to filter positive ions and photoelectrons in the vacuum environment, and allows the fluorescent signal to pass through and project to the electron channel multiplier tube assembly; the channel electron multiplier tube assembly amplifies the received fluorescent signal and forms a second current signal to migrate to the vacuum feedthrough; The signal collecting end is fixedly connected to the vacuum feedthrough via a supporting component.

[0010] Furthermore, the gold mesh assembly includes an insulating bolt and an outer insulating sleeve, a first layer of stainless steel ring, a first layer of gold mesh, an insulating ring, a second layer of gold mesh, and a second layer of stainless steel ring, which are coaxially connected and fixed in series in sequence by the insulating bolt; One side of the first stainless steel ring and the second stainless steel ring are connected with wires through fastening screws; the two wires are electrically connected to the vacuum feedthrough respectively, providing different voltages for the first gold mesh and the second gold mesh to filter positive ions and photoelectrons respectively.

[0011] Further, the channel electron multiplier tube assembly includes a channel electron multiplier tube, a channel electron multiplier tube support seat and a rubber pad; The electron channel multiplier tube is fixedly installed on the channel electron multiplier tube support seat by fixing screws through rubber pads; the positive and negative electrodes of the electron channel multiplier tube are respectively connected with wires by screws, and the other ends of the two wires are respectively electrically connected with vacuum feedthroughs, the negative electrode is used to form a voltage drop with the positive electrode, and the secondary electrons excited by the sample output fluorescence signal irradiating the channel electron multiplier tube are amplified, and the signal end of the electron channel multiplier tube is connected with a wire by screws, and the other end of the wire is electrically connected with the vacuum feedthrough for collecting the gained secondary electron signal.

[0012] Furthermore, the supporting component includes two stainless steel semi-cylinders, a stainless steel base, an insulating fixed base, and a vacuum venting screw; the insulating fixed base is fixed to the vacuum feedthrough by the vacuum venting screw, the stainless steel base is fixed to the insulating fixed base by the vacuum venting screw, the two stainless steel semi-cylinders are fixed to the screw holes on the sides of the stainless steel base by screws, the gold mesh assembly is fixed to the two stainless steel semi-cylinders by screws, and the channel electron multiplier tube assembly is fixed to the two stainless steel semi-cylinders by screws.

[0013] Further, the vacuum feedthrough includes a first ceramic electrode, a second ceramic electrode, a third ceramic electrode and a fourth ceramic electrode; The first ceramic electrode is electrically connected to the first stainless steel ring and the control circuit via a wire; The second ceramic electrode is electrically connected to the second stainless steel ring through a wire, and the second ceramic electrode is also electrically connected to the negative electrode of the channel electron multiplier tube and the control circuit through a wire; The third ceramic electrode is electrically connected to the positive electrode of the channel electron multiplier tube through a wire, and the third ceramic electrode is also electrically connected to the control circuit through a wire; The fourth ceramic electrode is electrically connected to the signal end of the channel electron multiplier tube through a wire, and the fourth ceramic electrode is also electrically connected to the numerical control terminal through a wire.

[0014] Further, the beam monitoring device includes a linear introducer, a gold mesh, a vacuum electrode and a microammeter; The linear introducer is connected to the gold mesh and the gold mesh is placed on the optical path of the synchrotron radiation by adjusting the introduction distance; the gold mesh is electrically connected to the vacuum electrode through a wire, and the other end of the vacuum electrode is electrically connected to the microammeter through a wire.

[0015] Furthermore, the numerical control unit includes a current amplifier, a signal acquisition card and a computer; The current amplifier is electrically connected to the fourth ceramic electrode and the signal end of the channel electron multiplier tube through a wire; the signal acquisition card collects the first current signal and the second current signal amplified by the current amplifier and outputs them to a computer; The computer controls the beam line monochromator to perform energy scanning on the sample and collects the first current signal and the second current signal sent by the signal acquisition card to generate a soft X-ray fluorescence absorption spectrum result.

[0016] The present invention has at least the following advantages: 1. The present invention abandons the traditional full electron yield mode and uses the full fluorescence yield mode to measure and explore the electronic structure of the material phase. In this process, because the full fluorescence yield mode detects and captures the fluorescence signal, the escape depth of the fluorescence signal is deep, usually reaching the level of hundreds of nanometers. Therefore, under this detection mode, the absorption spectrum information of elements at a depth of hundreds of nanometers can be detected, which significantly broadens the detection depth of the soft X-ray absorption spectrum and provides a strong guarantee for the exploration of the electronic structure of the material phase.

[0017] 2. The present invention arranges a heating resistor inside the sample stage and an in-situ illumination device around the sample stage. Under the control of a numerical control terminal, the light field and the thermal field can be simulated, thereby facilitating in-situ experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the in-situ soft X-ray fluorescence absorption spectrum acquisition system of the present invention; Figure 2 It is a three-dimensional structural diagram of the fluorescence signal acquisition device of the present invention; Figure 3 It is a schematic diagram of the structural explosion of the gold mesh assembly of the present invention; Figure 4 It is a structural explosion diagram of the channel electron multiplier tube assembly of the present invention; Figure 5 This is a schematic diagram of electrical connections of the fluorescence signal acquisition device of the present invention; Figure 6It is a schematic diagram of the working principle of the in-situ soft X-ray fluorescence absorption spectrum acquisition system of the present invention; Figure 7 The TiL-edge soft X-ray fluorescence absorption spectrum of the titanium oxide single crystal sample obtained by using the embodiment of the present invention; In the figure: 1: vacuum device; 2: sample stage; 3: beam monitoring device; 4: fluorescence signal acquisition device; 4-1: signal collection end; 4-2: vacuum feedthrough; 4-1-1: outer insulating sleeve; 4-1-2: first layer of stainless steel ring; 4-1-3: first layer of gold mesh; 4-1-4: insulating ring; 4-1-5: second layer of gold mesh; 4-1-6: second layer of stainless steel ring; 4-1-7: insulating bolt; 4-1-8: fastening screw; 4-1-9: channel Electron multiplier tube support seat; 4-1-10: channel electron multiplier tube; 4-1-11: rubber pad; 4-1-12: nut; 4-1-13: screw; 5: control circuit; 6: in-situ illumination device; 7: numerical control terminal; 7-1: current amplifier; 7-2 signal acquisition card; 7-3 computer; 8: beam line monochromator; 9: sample; 10: synchrotron radiation; 11: in-situ illumination; 12: positive ions; 13: sample emitted photoelectrons; 14: sample emitted fluorescence. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0020] like Figure 1 As shown, the present invention provides an in-situ soft X-ray fluorescence absorption spectrum acquisition system, comprising: a synchrotron radiation light source, a beam line monochromator, a beam current monitoring device and a sample stage which are linearly arranged in sequence; The synchrotron radiation light emitted by the synchrotron radiation source is monochromatized by the beam line monochromator and then projected onto the sample at the sample stage with a specific energy; the beam current monitoring device measures the synchrotron radiation beam current intensity in real time and generates a first current signal to feed back to the numerical control terminal; A fluorescence signal collection device is arranged around the sample stage, and the fluorescence signal collection device is used to capture the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation, and generate a second current signal to feed back to the numerical control terminal; A control circuit, the control circuit is used to provide the operating voltage required for the normal operation of the fluorescence signal acquisition device and has an overvoltage protection function; The monochromatization process of the synchrotron radiation light, the beam intensity detection process, the sample irradiation process and the fluorescence signal capture process are all carried out in a vacuum environment provided by a vacuum device; The numerical control terminal is configured to control the beam line monochromator to perform energy scanning on the sample, and to generate a soft X-ray fluorescence absorption spectrum result by integrating the first current signal and the second current signal received in real time.

[0021] The vacuum device only needs to be able to maintain the vacuum degree at 1×10 -9 Up to 1×10 -10 Millibars are sufficient. Existing vacuum devices are mature in technology and fully functional. This embodiment can directly use existing vacuum devices. As a known technology, its structure and working principle are not described in detail here. The soft X-ray fluorescence absorption spectrum results reflect the bulk electronic structure information of the material, and the in-situ soft X-ray fluorescence absorption spectrum reflects the bulk electronic structure information of the material under the in-situ conditions. The solution provided by the embodiment of the present invention can effectively improve the characterization depth of the absorption spectrum, and at the same time effectively reveal the changes in the electronic structure of the material under in-situ conditions.

[0022] An in-situ illumination device is also set up around the sample stage; the in-situ illumination device changes the illumination intensity under the control of the numerical control terminal to provide different illumination conditions for the sample; The sample stage is provided with a thermocouple and a heating resistor. The numerical control terminal controls the input voltage of the heating resistor through a wire to change the power of the heating resistor and provide different temperature conditions for the sample. The thermocouple feeds back the current temperature information of the heating resistor to the numerical control terminal in real time.

[0023] The sample stage 2 is placed on the sample holder in the vacuum device 1, and the sample 9 is mounted on the sample stage 2. The sample stage 2 has a thermocouple and a resistor and is electrically connected to the sample holder. The sample holder is electrically connected to an external instrument, so that the sample can be heated in situ.

[0024] The in-situ illumination device 6 comprises: a light source and a fixing device. The light source is fixed to the outside of the quartz window on the vacuum cavity of the vacuum device 1 by the fixing device. During testing, the light source can be turned on to provide in-situ illumination conditions. The light source is an ultraviolet LED light source.

[0025] like Figure 2-Figure 4 As shown, the fluorescence signal collection device includes: a signal collection end and a vacuum feedthrough; the signal collection end is fixedly connected to the vacuum feedthrough, and the vacuum feedthrough is fixedly installed on the side wall of the vacuum device through a flange port; the size of the vacuum feedthrough mounting flange is DN40CF; The signal collecting end captures and collects the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation to generate a second current signal and transfers it to the vacuum feedthrough; the vacuum feedthrough feeds back the second current signal to the numerical control terminal through a wire.

[0026] The signal collection end includes a coaxially mounted gold mesh assembly, a channel electron multiplier tube assembly and a supporting component; The gold mesh assembly is used to filter positive ions and photoelectrons in the vacuum environment, and allows the fluorescent signal to pass through and project to the electron channel multiplier tube assembly; the channel electron multiplier tube assembly amplifies the received fluorescent signal and forms a second current signal to migrate to the vacuum feedthrough; The signal collecting end is fixedly connected to the vacuum feedthrough via a supporting component.

[0027] The gold mesh assembly and the channel electron multiplier tube assembly are mounted on the support component via M3 screws, and the support component is mounted on the vacuum feedthrough via M3 screws.

[0028] The gold mesh assembly includes an insulating bolt, and an outer insulating sleeve, a first layer of stainless steel ring, a first layer of gold mesh, an insulating ring, a second layer of gold mesh, and a second layer of stainless steel ring, which are coaxially connected and fixed in series in sequence through the insulating bolt; One side of the first stainless steel ring and the second stainless steel ring are connected with wires through fastening screws; the two wires are electrically connected to the vacuum feedthrough respectively, providing different voltages for the first gold mesh and the second gold mesh to filter positive ions and photoelectrons respectively.

[0029] The stainless steel ring, gold mesh and insulating ring form a "sandwich" structure, which is fixed in the outer insulating sleeve by insulating bolts. The two layers of gold mesh are in close contact with the stainless steel rings they are in contact with, and the voltages on the two layers of gold mesh are provided by the wires fixed on the stainless steel rings. The transmittance of the first layer of gold mesh 4-1-3 and the second layer of gold mesh 4-1-5 is greater than 85%. The first layer of stainless steel ring and the second layer of stainless steel ring are made of stainless steel 316L, and the outer insulating sleeve, insulating ring and insulating bolt are made of PEEK. The fastening screw 4-1-8 is an M1.6 stud.

[0030] like Figure 4 As shown, the channel electron multiplier tube assembly includes a channel electron multiplier tube, a channel electron multiplier tube support seat and a rubber pad; The electron channel multiplier tube is fixedly installed on the channel electron multiplier tube support seat by fixing screws through rubber pads; the positive and negative electrodes of the electron channel multiplier tube are respectively connected with wires by screws, and the other ends of the two wires are respectively electrically connected with vacuum feedthroughs, the negative electrode is used to form a voltage drop with the positive electrode, and the secondary electrons excited by the sample output fluorescence signal irradiating the channel electron multiplier tube are amplified, and the signal end of the electron channel multiplier tube is connected with a wire by screws, and the other end of the wire is electrically connected with the vacuum feedthrough for collecting the gained secondary electron signal.

[0031] The channel electron multiplier tube support seat is made of PEEK, and the rubber pad is made of fluorine-containing rubber.

[0032] The supporting component includes two stainless steel semi-cylinders, a stainless steel base, an insulating fixed base, and a vacuum venting screw; the insulating fixed base is fixed to the vacuum feedthrough by the vacuum venting screw, the stainless steel base is fixed to the insulating fixed base by the vacuum venting screw, the two stainless steel semi-cylinders are fixed to the screw holes on the sides of the stainless steel base by screws, the gold mesh assembly is fixed to the two stainless steel semi-cylinders by screws, and the channel electron multiplier tube assembly is fixed to the two stainless steel semi-cylinders by screws.

[0033] The stainless steel semi-cylinder and the stainless steel base are made of stainless steel, and the insulating fixed base is made of PEEK.

[0034] like Figure 5 As shown, the vacuum feedthrough includes a first ceramic electrode, a second ceramic electrode, a third ceramic electrode and a fourth ceramic electrode; The first ceramic electrode is electrically connected to the first stainless steel ring and the control circuit via a wire; The second ceramic electrode is electrically connected to the second stainless steel ring through a wire, and the second ceramic electrode is also electrically connected to the negative electrode of the channel electron multiplier tube and the control circuit through a wire; The third ceramic electrode is electrically connected to the positive electrode of the channel electron multiplier tube through a wire, and the third ceramic electrode is also electrically connected to the control circuit through a wire; The fourth ceramic electrode is electrically connected to the signal end of the channel electron multiplier tube through a wire, and the fourth ceramic electrode is also electrically connected to the numerical control terminal through a wire.

[0035] The control circuit 5 is connected to the vacuum feedthrough 4-2 through a wire, and is used to provide the working voltage required for the normal operation of the fluorescence signal collection device 4, and has an overvoltage protection function. The control circuit 5 applies a positive voltage in the range of +50-100V to the first ceramic electrode and the first layer of gold mesh 4-1-2 electrically connected to the first ceramic electrode, which is used to shield the positive ions in the vacuum chamber. The control circuit 5 applies a negative voltage in the range of -1000 to -2500V to the second ceramic electrode and the second layer of gold mesh 4-1-5 electrically connected to the second ceramic electrode and the negative electrode of the channel electron multiplier tube. The second layer of gold mesh is used to shield the photoelectrons emitted from the sample 9. The negative electrode of the channel electron multiplier tube is used to form a voltage drop with the positive electrode, and the secondary electrons excited by the fluorescence signal emitted by the sample 9 irradiated on the channel electron multiplier tube are amplified. The control circuit 5 is connected to the third ceramic electrode and the positive electrode of the channel electron multiplier tube electrically connected to the third ceramic electrode to form a voltage divider circuit, which is used to promote the migration of the amplified secondary electron signal to the signal end of the channel electron multiplier tube and be collected.

[0036] The beam monitoring device includes a linear introducer (manufacturer: Fei Mian / model: LTM35L200M), a gold mesh (manufacturer: Precisioneforming / model: MG49117.6LPIAu Mesh 11x11), a vacuum electrode and a microammeter (manufacturer: KEITHLEY / model: 6517A); The linear introducer is connected to the gold mesh and the gold mesh is placed on the optical path of the synchrotron radiation by adjusting the introduction distance; the gold mesh is electrically connected to the vacuum electrode through a wire, and the other end of the vacuum electrode is electrically connected to the microammeter through a wire.

[0037] The transmittance of the gold mesh is better than 85%, and the weak current signal measured by the microammeter reflects the beam intensity of the synchrotron radiation light.

[0038] The numerical control unit includes a current amplifier, a signal acquisition card and a computer; The current amplifier is electrically connected to the fourth ceramic electrode and the signal end of the channel electron multiplier tube through a wire; the signal acquisition card collects the first current signal and the second current signal amplified by the current amplifier and outputs them to a computer; The computer controls the beam line monochromator to perform energy scanning on the sample and collects the first current signal and the second current signal sent by the signal acquisition card to generate a soft X-ray fluorescence absorption spectrum result.

[0039] like Figure 6 As shown, when the test is carried out, the monochromatized synchrotron radiation light 10 irradiates the sample, the sample output photoelectron 13 signal is intercepted by the second layer of gold mesh 4-1-5, the positive ions 12 in the vacuum device are intercepted by the first layer of gold mesh 4-1-3, and the sample output fluorescence 14 signal is collected and amplified by the current amplifier 7-1 after gain by the channel electron multiplier tube 4-1-10, and then collected by the signal acquisition card 7-2, and finally a soft X-ray fluorescence absorption spectrum result is generated on the computer 7-3. When the sample is subjected to in-situ heating treatment or in-situ illumination 11 is applied, an in-situ soft X-ray fluorescence absorption spectrum result is generated.

[0040] In this embodiment, in the computer software program, parameters such as the synchrotron radiation photon energy scanning range, scanning step length, and dwell time are set. The synchrotron radiation source is turned on, and the synchrotron radiation light 10 passes through the gold mesh of the beam monitoring device 3 and irradiates the surface of the sample 9 to be tested. The soft X-ray fluorescence absorption spectrum test is started, and the weak current signal obtained by the beam monitoring device 3 and the signal obtained by the fluorescence signal acquisition device 4 after amplification by the current amplifier 7-1 are collected by the data acquisition card 7-2 and entered into the computer 7-3 software program, and the soft X-ray fluorescence absorption spectrum is output after calculation.

[0041] Experimental example: The sample to be tested is a titanium oxide single crystal, and the vacuum degree of the vacuum chamber is 4×10 -9 mbar, the working voltage of the first layer of gold mesh is +100 volts, the working voltage of the second layer of gold mesh is -1800 volts, the negative voltage of the channel electron multiplier tube is -1800 volts, and the positive voltage of the channel electron multiplier tube is 0 volts, so we get Figure 7 The TiL-edge soft X-ray fluorescence absorption spectrum of the titanium oxide single crystal sample in full fluorescence yield mode is shown, confirming that the in-situ soft X-ray fluorescence absorption spectrum acquisition system works normally.

Claims

1. In-situ soft X-ray fluorescence absorption spectrum acquisition system, characterized in that: include: A synchrotron radiation source, beam line monochromator, beam monitoring device and sample stage are arranged linearly in sequence; The synchrotron radiation light emitted by the synchrotron radiation source is monochromatized by the beam line monochromator and then projected onto the sample at the sample stage with a specific energy; the beam current monitoring device measures the synchrotron radiation beam current intensity in real time and generates a first current signal to feed back to the numerical control terminal; A fluorescence signal collection device is arranged around the sample stage, and the fluorescence signal collection device is used to capture the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation, and generate a second current signal to feed back to the numerical control terminal; A control circuit, the control circuit is used to provide the operating voltage required for the normal operation of the fluorescence signal acquisition device and has an overvoltage protection function; The monochromatization process of the synchrotron radiation light, the beam intensity detection process, the sample irradiation process and the fluorescence signal capture process are all carried out in a vacuum environment provided by a vacuum device; The numerical control terminal is configured to control the beam line monochromator to perform energy scanning on the sample, and to generate a soft X-ray fluorescence absorption spectrum result by integrating the first current signal and the second current signal received in real time.

2. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 1, characterized in that: An in-situ illumination device is also set up around the sample stage; the in-situ illumination device changes the illumination intensity under the control of the numerical control terminal to provide different illumination conditions for the sample; The sample stage is provided with a thermocouple and a heating resistor. The numerical control terminal controls the input voltage of the heating resistor through a wire to change the power of the heating resistor and provide different temperature conditions for the sample. The thermocouple feeds back the current temperature information of the heating resistor to the numerical control terminal in real time.

3. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 1, characterized in that: The fluorescence signal collection device comprises: a signal collection end and a vacuum feedthrough; the signal collection end is fixedly connected to the vacuum feedthrough, and the vacuum feedthrough is fixedly installed on the side wall of the vacuum device through a flange port; The signal collecting end captures and collects the fluorescence signal emitted by the sample after being irradiated by synchrotron radiation to generate a second current signal and transfers it to the vacuum feedthrough; the vacuum feedthrough feeds back the second current signal to the numerical control terminal through a wire.

4. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 3, characterized in that: The signal collection end includes a coaxially mounted gold mesh assembly, a channel electron multiplier tube assembly and a supporting component; The gold mesh assembly is used to filter positive ions and photoelectrons in the vacuum environment, and allows the fluorescent signal to pass through and project to the electron channel multiplier tube assembly; the channel electron multiplier tube assembly amplifies the received fluorescent signal and forms a second current signal to migrate to the vacuum feedthrough; The signal collecting end is fixedly connected to the vacuum feedthrough via a supporting component.

5. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 4, characterized in that: The gold mesh assembly includes an insulating bolt, and an outer insulating sleeve, a first layer of stainless steel ring, a first layer of gold mesh, an insulating ring, a second layer of gold mesh, and a second layer of stainless steel ring, which are coaxially connected and fixed in series in sequence through the insulating bolt; One side of the first stainless steel ring and the second stainless steel ring are connected with wires through fastening screws; the two wires are electrically connected to the vacuum feedthrough respectively, providing different voltages for the first gold mesh and the second gold mesh to filter positive ions and photoelectrons respectively.

6. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 4, characterized in that: The channel electron multiplier tube assembly comprises a channel electron multiplier tube, a channel electron multiplier tube support seat and a rubber pad; The electron channel multiplier tube is fixedly installed on the channel electron multiplier tube support seat by fixing screws through rubber pads; the positive and negative electrodes of the electron channel multiplier tube are respectively connected with wires by screws, and the other ends of the two wires are respectively electrically connected with vacuum feedthroughs, the negative electrode is used to form a voltage drop with the positive electrode, and the secondary electrons excited by the sample output fluorescence signal irradiating the channel electron multiplier tube are amplified, and the signal end of the electron channel multiplier tube is connected with a wire by screws, and the other end of the wire is electrically connected with the vacuum feedthrough for collecting the gained secondary electron signal.

7. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 4, characterized in that: The supporting component includes two stainless steel semi-cylinders, a stainless steel base, an insulating fixed base, and a vacuum venting screw; the insulating fixed base is fixed to the vacuum feedthrough by the vacuum venting screw, the stainless steel base is fixed to the insulating fixed base by the vacuum venting screw, the two stainless steel semi-cylinders are fixed to the screw holes on the sides of the stainless steel base by screws, the gold mesh assembly is fixed to the two stainless steel semi-cylinders by screws, and the channel electron multiplier tube assembly is fixed to the two stainless steel semi-cylinders by screws.

8. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 3, characterized in that: The vacuum feedthrough comprises a first ceramic electrode, a second ceramic electrode, a third ceramic electrode and a fourth ceramic electrode; The first ceramic electrode is electrically connected to the first stainless steel ring and the control circuit via a wire; The second ceramic electrode is electrically connected to the second stainless steel ring through a wire, and the second ceramic electrode is also electrically connected to the negative electrode of the channel electron multiplier tube and the control circuit through a wire; The third ceramic electrode is electrically connected to the positive electrode of the channel electron multiplier tube through a wire, and the third ceramic electrode is also electrically connected to the control circuit through a wire; The fourth ceramic electrode is electrically connected to the signal end of the channel electron multiplier tube through a wire, and the fourth ceramic electrode is also electrically connected to the numerical control terminal through a wire.

9. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 1, characterized in that: The beam monitoring device comprises a linear introducer, a gold mesh, a vacuum electrode and a micro-ammeter; The linear introducer is connected to the gold mesh and the gold mesh is placed on the optical path of the synchrotron radiation by adjusting the introduction distance; the gold mesh is electrically connected to the vacuum electrode through a wire, and the other end of the vacuum electrode is electrically connected to the microammeter through a wire.

10. The in-situ soft X-ray fluorescence absorption spectrum acquisition system according to claim 1, characterized in that: The numerical control unit includes a current amplifier, a signal acquisition card and a computer; The current amplifier is electrically connected to the fourth ceramic electrode and the signal end of the channel electron multiplier tube through a wire; the signal acquisition card collects the first current signal and the second current signal amplified by the current amplifier and outputs them to a computer; The computer controls the beam line monochromator to perform energy scanning on the sample and collects the first current signal and the second current signal sent by the signal acquisition card to generate a soft X-ray fluorescence absorption spectrum result.

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