Holographic grating direct-current emission spectrometer

Abstract

The utility model belongs to the field of spectral analysis equipment, and particularly discloses a holographic grating direct-current emission spectrometer which comprises a direct-current arc generation mechanism and a spectral analysis mechanism which are arranged in an integrated mode. The spectral analysis mechanism comprises a base, a front panel, a light inlet assembly, a holographic grating, a rear reflecting plate and a detector, the front panel is fixedly connected to one end of the base, the light inlet assembly, the holographic grating and the detector are all arranged on the front panel, and the rear reflecting plate is slidably connected to the base; the direct-current arc generating mechanism is arranged at one end, close to the front panel, of the base so as to enable light rays generated by the excitation sample to penetrate through the light inlet assembly, then enter the space between the front panel and the rear reflecting plate, and enter the detector after being reflected by the holographic grating and the rear reflecting plate. The volume of the device is reduced, the device is convenient to carry to a sampling area, the collected sample is detected and analyzed in time, the detection efficiency is high, the detection result is accurate, and the progress of spectral analysis work is improved.

Description

Technical Field

[0001] This application belongs to the field of spectral analysis equipment, and more specifically, relates to a holographic grating direct current emission spectrometer. Background Art

[0002] A direct-reading emission spectrometer is a spectral instrument with medium dispersion rate. It uses a spectroscopic optical system to decompose the composite light generated by an arc-excited sample into spectral lines of different bands through a mirror and a grating, and an electronic circuit detection system analyzes the data of the spectral lines of different bands to obtain accurate analysis data. It is mainly used for spectral analysis of soil, rock and minerals.

[0003] Chinese Patent with application number 201520235385.X discloses a spectrograph with a holographic high-density grating, including an excitation mechanism, a condenser mechanism and a dispersion mechanism connected in sequence; the excitation mechanism includes a first housing, two electrodes are arranged in the first housing, a material table is arranged between the two electrodes, and the two electrodes are respectively connected to a power supply through wires to generate a spectrum by exciting the sample material to emit light; the condenser mechanism includes a base, on which a first condenser lens, a second condenser lens and a third condenser lens that are parallel to each other and have the same height are arranged in sequence, and a light-shielding device for restricting the light flux of incident light is arranged between the first condenser lens and the second condenser lens; the light-shielding device includes two light-shielding plates, the two light-shielding plates are connected by an adjusting screw, and the adjusting screw is used to finely adjust the distance between the slits of the two light-shielding plates; the dispersion mechanism includes a second housing, in which a plane mirror, a first concave mirror, a grating and a second concave mirror are arranged. This spectrograph can accurately measure the wavelength and convert the dispersed spectrum into a digital signal.

[0004] Due to its complex structure and large volume, the existing spectrograph is usually placed in a laboratory for use and is not convenient to carry. Therefore, it is impossible to accurately detect and analyze the collected samples in time. Since soil, rock and mineral samples usually need to be collected at different positions in the wild, and then various samples are transported to the laboratory for centralized spectral analysis, this process takes a lot of time, resulting in a longer time to obtain the sample detection and analysis results. Moreover, during the sample collection process, usually the next sample collection coordinate point needs to be determined according to the sample detection and analysis results of the previous step. Since the sample detection and analysis data cannot be obtained in time, the subsequent sample collection positions are prone to errors, thus affecting the progress of the spectral analysis work of soil, rock and minerals. Summary of the Utility Model

[0005] Aiming at the defects of the existing technology, this application provides a holographic grating direct current emission spectrometer, aiming to solve the problems that the existing grating spectrograph is limited by its large volume and is not convenient to carry, resulting in the inability to obtain the sample detection and analysis results in time and the inability to accurately locate the next sample collection coordinate point.

[0006] A holographic grating direct-current emission spectrometer provided by the present application specifically includes an integrated direct-current arc generating mechanism and a spectral analysis mechanism; the spectral analysis mechanism includes a base, a front panel, a light incident component, a holographic grating, a rear reflector and a detector, the front panel is fixedly connected to one end of the base, the light incident component, the holographic grating and the detector are all arranged on the front panel, the rear reflector is slidably connected to the base to be close to or far from the detector, and the rear reflector is a spherical mirror; the direct-current arc generating mechanism is arranged at one end of the base close to the front panel to enable the light generated by exciting a sample to pass through the light incident component and then enter between the front panel and the rear reflector, and after being reflected by the holographic grating and the rear reflector, enter the detector.

[0007] Through the above technical solution conceived by the present application, compared with the prior art, since the direct-current arc generating mechanism and the spectral analysis mechanism are integrally arranged in the present application, the distance from the light emitted by the sample on the direct-current arc generating mechanism to the spectral analysis mechanism for detection and analysis is greatly shortened, the volume of the device is reduced, and it is convenient to carry. Moreover, by adjusting the position of the rear reflector, the distance between the front panel and the rear reflector can be adjusted. There are multiple reflection optical paths for the spectral lines passing through the holographic grating and the rear reflector. During the adjustment process, the incident light and the reflected light are adjusted simultaneously to achieve the adjustment of the focal length, so as to facilitate the detector to receive the reflected light for detection and analysis, improve the accuracy and efficiency of the spectral detection results of different samples, and the spectrometer of the present application can be easily carried to the sampling area and timely detect and analyze different samples, with high detection efficiency, accurate detection results, and the detection and analysis results can be obtained faster, thereby improving the process of spectral analysis work.

[0008] As a further preference, the direct-current arc generating mechanism includes a mounting frame and two electrode clamps arranged symmetrically up and down; both of the two electrode clamps are arranged on the mounting frame; the mounting frame includes a horizontally arranged bottom plate and a vertically arranged column, the bottom plate is fixedly connected to one end of the base close to the front panel and the bottom plate and the base are on the same straight line, the column is fixedly connected to the end of the bottom plate far from the base; the direct-current arc generating mechanism further includes a mounting member, both of the two electrode clamps are detachably connected to the column through the mounting member, and the positions of the two electrode clamps are adjustable.

[0009] By adopting the above technical solution, after the sample is excited to generate light, the light can propagate linearly through the front panel, shortening the propagation distance, thereby reducing the volume of the device. The electrode clamp and the mounting frame are detachably connected, which is convenient for disassembly, maintenance and repair.

[0010] As a further preference, the mounting member is an integral structure or includes two sub-mounting members, and the two sub-mounting members are respectively connected to the corresponding electrode clamps.

[0011] By adopting the above technical solution, a suitable mounting structure of the mounting part is selected according to the actual use needs, so as to facilitate the installation of the electrode clamp.

[0012] As a further preference, the sub-mounting part includes a mounting block, a threaded locking part, a connecting rod and a connecting block. A through hole for the column to pass through is formed in the mounting block. The threaded locking part is threadedly connected to the mounting block and one end extends into the through hole. One end of the connecting rod is fixedly connected to the mounting block, and the other end is fixedly connected to the connecting block. A clamping groove for mounting the electrode clamp is formed in the connecting block.

[0013] By adopting the above technical solution, the mounting block is sleeved on the mounting frame and the threaded locking part is rotated to abut against the mounting frame, so as to fix the mounting block. The electrode clamp is mounted in the clamping groove on the connecting block, making the installation more stable.

[0014] As a further preference, the DC arc generating mechanism further includes a DC arc exciter, and the DC arc exciter is electrically connected to the two electrode clamps respectively.

[0015] By adopting the above technical solution, the DC arc exciter is used to energize the upper electrode clamp and the lower electrode clamp, and the sample is excited by the continuous current of the high-power switching power supply, so that the sample generates composite light at high temperature and emits characteristic spectra with different intensities and different wavelength bands correspondingly.

[0016] As a further preference, the light inlet assembly includes a light inlet tube and a slit member. The light inlet tube is fixedly connected to the front panel through the slit member, and the light enters the light inlet tube and then the light quantity is changed by the slit member and then emitted.

[0017] By adopting the above technical solution, the light enters the light inlet tube to separate stray light, focuses the excitation light source on the slit, so that the light intensity entering the slit is the largest, and the light quantity of the light inlet tube is adjusted through the slit member, and the intensity of the spectral line can be changed.

[0018] As a further preference, the holographic grating is connected to the front panel and is located below the slit member, and the holographic grating can rotate with the central axis in its vertical direction as the rotation axis.

[0019] By adopting the above technical solution, the holographic grating is located below the slit member to facilitate the reflection of light, avoid interfering with the incident light, and the light angle can be adjusted to improve the detection effect.

[0020] As a further preference, the spectral analysis mechanism further includes a baffle with windows, which is arranged on the rear reflector and is successively provided with a first light reflection window and a second light reflection window in the vertical direction. After the light passes through the first light reflection window, the incident light is reflected to the holographic grating by the rear reflector, and the light reflected by the holographic grating passes through the second light reflection window and is reflected to the detector by the rear reflector again.

[0021] By adopting the above technical solution, when the rear reflector moves, it drives the first light reflection window and the second light reflection window to move at the same time, and the incident light and the reflected light are adjusted simultaneously, simplifying the focusing method and improving the adjustment efficiency.

[0022] As a further preference, a fine adjustment driving component for driving the rear reflector to move is arranged on the base, and the moving direction of the rear reflector is the same as the light incident direction of the DC arc generating mechanism.

[0023] By adopting the above technical solution, the fine adjustment driving component is set to fine-tune the moving distance of the rear reflector, improving the accuracy of the position adjustment of the rear reflector.

[0024] As a further preference, the fine adjustment driving component includes a fixed seat, a screw rod and a nut. The fixed seat is fixedly connected to the base. The screw rod is rotatably connected to the fixed seat and its axis is arranged along the moving direction of the rear reflector. The nut is fixedly connected to the bottom of the rear reflector and is in threaded connection with the screw rod.

[0025] By adopting the above technical solution, rotating the screw rod drives the nut and the rear reflector to move. The structure is simple, the adjustment is convenient, and the adjustment amplitude is small to achieve fine adjustment.

[0026] Generally speaking, compared with the prior art by the above technical solutions conceived in the present application, the following technical advantages are mainly possessed:

[0027] 1. In the spectrometer of the present application, the DC arc generating mechanism and the spectral analysis mechanism are integrally arranged and located on the same straight line, shortening the optical path and greatly reducing the distance from the sample emission light on the DC arc generating mechanism to the spectral analysis mechanism for detection and analysis. The integrated design can reduce the volume of the device, making it convenient to carry around, so that the sample can be detected and analyzed in a timely manner after sampling. The detection efficiency is high, the detection result is accurate, and the detection and analysis result can be obtained faster, which is convenient for determining the next sample collection coordinate point according to the sample detection and analysis result of the previous step, improving the process of spectral analysis work. In addition, by adjusting the distance between the front panel and the rear reflector, the optical path of the multiple reflections between the holographic grating and the rear reflector of the spectral line is adjusted. During the adjustment process, the incident light and the reflected light are adjusted simultaneously to achieve the adjustment of the focal length, which can be flexibly adjusted according to the sample detection needs, so that the detector can receive the reflected light for detection and analysis, improving the accuracy and efficiency of the spectral detection results of different samples.

[0028] 2. In the present application, the electrode clamp is detachably connected to the mounting bracket to facilitate disassembly, maintenance, and repair, ensuring that the sample to be measured can be stably clamped during use.

[0029] 3. By changing the installation position of the bottom plate, the distance between the electrode clamp and the front panel is adjusted, so that the distance from the sample emission light to the front panel can be adjusted, which can be adjusted according to the sample detection needs, improving the applicability of the present application. Description of the Drawings

[0030] Figure 1 is the overall structural schematic diagram of the spectrometer provided in Embodiment 1 from the first perspective;

[0031] Figure 2 is the overall structural schematic diagram of the spectrometer provided in Embodiment 1 from the second perspective;

[0032] Figure 3 is Figure 2 the enlarged structural schematic diagram of part A in

[0033] Figure 4 is the overall structural schematic diagram of the spectrometer provided in Embodiment 2.

[0034] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0035] 1. DC arc generating mechanism; 11. Mounting frame; 111. Base plate; 112. Column; 12. Electrode clamp; 13. Sub-mounting member; 131. Mounting block; 1311. Perforation; 132. Threaded locking member; 133. Connecting rod; 134. Connecting block; 1341. Card slot; 2. Spectral analysis mechanism; 21. Base; 22. Front panel; 23. Light incident component; 231. Light incident tube; 232. Slit member; 24. Holographic grating; 25. Rear reflector; 26. Baffle with window; 261. First reflective window; 262. Second reflective window; 27. Detector; 28. Fine-tuning drive assembly; 281. Fixed seat; 282. Screw; 283. Nut; 29. Connecting plate. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] Embodiment 1:

[0038] Referring to Figures 1-3 , a holographic grating DC emission spectrometer disclosed in the present application includes an integrally arranged DC arc generating mechanism 1 and a spectral analysis mechanism 2; the DC arc generating mechanism 1 and the spectral analysis mechanism 2 are arranged on the same straight line, and the spectral analysis mechanism 2 is used to detect and analyze the light generated by the DC arc generating mechanism 1. Under this design, the overall device can shorten the optical path during spectral detection, simplify the structure, reduce the volume of the device, facilitate carrying, and can realize timely detection and analysis of the collected samples. The analysis results are accurate and can be obtained faster, which is convenient for determining the next sample collection coordinate points according to the sample detection and analysis results of the previous step, greatly promoting the process of spectral analysis of soil, rock and minerals. In the original spectrograph (a spectrograph with a holographic high-density grating, Chinese patent with application number CN201520235385.X), the composite light enters the spectroscopic system through the slit and is split to the detector, and the total optical path is about 4 meters. The total optical path of the present application is about 2.6 meters, which greatly shortens the optical path, effectively improves the intensity of spectral lines, increases the detection limit of low-sensitivity spectral lines, and improves the accuracy of analysis results.

[0039] Specifically, the volume of the arc generating mechanism in the original spectrograph is about 1 m 3 , and it is a two-part split structure, with extremely high heat generation, the overall power of 3000 w, and the working efficiency of about 30%. The volume of the integrated DC arc generating mechanism is about 0.007 m 3(280mm * 210mm * 110mm) The maximum power of the whole machine is about 1000w, and the working efficiency reaches over 95%; the appearance of the spectral analysis mechanism in the original spectrograph is an L-shaped structure with dimensions of about 1300mm * 400mm * 1300mm, having a long and complex external optical axis spectroscopic lens system. In this application, the overall appearance size of the spectral analysis mechanism is (1500mm * 350mm * 400mm), greatly reducing the overall volume of the equipment and improving the working efficiency of the equipment. That is, the overall appearance size of the original equipment is about 1300mm * 1400mm * 1300mm, and its weight is about 100kg. The overall appearance size of the equipment in this application is about 1780mm * 350mm * 400mm, and the weight is about 20kg, greatly reducing in terms of volume and weight, making it convenient to carry.

[0040] More specifically, the process of using the original spectrograph to detect samples is as follows: field sample collection, solid samples at different coordinates and depths in rocks, underground soil, or watercourse beds are collected through drilling, and then transported to the laboratory by logistics or self-transportation. After multi-stage sample processing such as coarse crushing and fine crushing, they are analyzed and tested by the instrument. It takes about three days to complete the analysis data for one sample from collection to obtaining. Among them, the transportation of the sample from the field to the laboratory takes a relatively long time. The sample collection takes about one day. If self-transported, it takes about one day from the field operation area to the laboratory, and the transportation cost is high. If transported by logistics, it takes at least two days, and the transportation timeliness cannot be guaranteed.

[0041] Experimental data shows that the analysis results of the spectrograph in this application are significantly improved compared with those of the traditional spectrograph. Specifically, a series of comparison experiments are conducted on volatile elements, moderately volatile elements, and refractory elements in geological samples in this application. Six national standard substances are selected, and under the same sample pretreatment conditions and the same experimental environment, the spectrograph in this application and the traditional spectrograph are respectively used for spectroscopic experiments. Each sample is spectroscopically analyzed 12 times, and their relative standard deviation (RSD) and relative error (RE) are calculated correspondingly. The summary comparison data is shown in the following table: where GBW refers to national primary standard substances, and GSD refers to standard substances of stream sediments.

[0042] Volatile elements B, Sn, Ag

[0043]

[0044] Moderately volatile elements Li, Be, refractory element Nb

[0045]

[0046] It can be seen from the comparison of AC / DC experimental data that the accuracy and precision of each element under DC excitation are comparable to those under AC excitation, and the data of some elements are better than those under AC excitation; the analytical performance of each element meets the requirements of the Specification for Quality Control of Tests in Geological and Mineral Laboratories (DZ / T 0130-2006).

[0047] The process of detecting samples in this application is as follows: Use common off-road vehicles or special operation vehicles to bring the equipment to the field sample collection site. Drill and collect solid samples at different coordinates and depths in rocks, underground soils or watercourse beds. After multi-stage sample processing of coarse crushing and fine crushing, conduct instrument analysis and testing; it takes about half a day to complete from sample collection to obtaining analysis data for one sample. After obtaining the experimental data, further arrange the sampling work for the target element, and repeat the above work repeatedly to determine the coordinate points where the target element is located. Therefore, the sample collection team does not need to wait too long for the analysis data. The field environment is harsh and changeable, and the costs of drilling equipment and personnel are high, which greatly saves the time and economic costs of the sample collection team and effectively improves the work efficiency of the field operation team.

[0048] In this embodiment, the DC arc generating mechanism 1 includes a mounting frame 11, a mounting member, and two electrode clamps 12 arranged symmetrically up and down. The mounting frame 11 includes a horizontally arranged bottom plate 111 and a vertically arranged column 112. The bottom plate 111 is welded to one end of the base 21 close to the front panel 22, and the bottom plate 111 and the base 21 are on the same straight line. The column 112 is fixedly connected to the end of the bottom plate 111 away from the base 21. Both electrode clamps 12 are detachably connected to the column 112 through the mounting member, and the positions of the electrode clamps 12 on the column 112 are adjustable. The electrode clamps 12 are clamps commonly used in the art for clamping samples, and the specific structure will not be elaborated. Specifically, the mounting member is an integral structure or includes two sub-mounting members 13. When the mounting member is an integral structure, both electrode clamps 12 are fixedly connected to the mounting member by screws, and the mounting member is connected to the column 112 by screws. In this embodiment, the two sub-mounting members 13 are respectively connected to the corresponding electrode clamps 12. To facilitate the installation of the electrode clamps 12, the sub-mounting member 13 includes a mounting block 131, a threaded locking member 132, a connecting rod 133, and a connecting block 134. A through hole 1311 for the column 112 to pass through is provided on the mounting block 131. The threaded locking member 132 is threadedly connected to the mounting block 131 and one end extends into the through hole 1311. After the mounting block 131 is sleeved on the mounting frame 11, rotate the threaded locking member 132 to make it abut against the mounting frame 11 to fix the mounting block 131. One end of the connecting rod 133 is fixedly connected to the mounting block 131, and the other end is fixedly connected to the connecting block 134. A card slot 1341 for installing the electrode clamp 12 is provided on the connecting block 134. The electrode clamp 12 is fixedly connected to the connecting block 134 by screws and is located in the card slot 1341.

[0049] Furthermore, the DC arc generating mechanism 1 further includes a DC arc exciter. The positive and negative electrodes of the DC arc exciter are respectively connected to two electrode clamps 12. The two electrode clamps 12 hold a sample. The sample generates composite light at high temperature under the excitation of the DC arc exciter and correspondingly emits characteristic spectra with different intensities and different wavelength bands. At the same time, this application uses control and data analysis software to control the start and stop of arc excitation, sets the excitation time and data acquisition time according to the performance of the analyzed sample, analyzes and reorganizes the acquired data. By collecting the characteristic spectral line intensities of several known standard samples and using a variety of mathematical models to fit the standard curve, and then analyzing the characteristic spectral line intensities of the unknown sample to calculate the analysis result and output it.

[0050] In this embodiment, the spectral analysis mechanism 2 includes a base 21, a front panel 22, a light incident component 23, a holographic grating 24, a rear reflector 25, and a detector 27. The front panel 22 is fixedly connected to one end of the base 21. The light incident component 23, the holographic grating 24, and the detector 27 are all arranged on the front panel 22. The detector 27 is a commonly used light detector 27 in the art. In this embodiment, a CCD detector 27 is used. The rear reflector 25 is slidably connected to the base 21 to approach or move away from the detector 27. The moving direction of the rear reflector 25 is the same as the light incident direction of the DC arc generating mechanism 1. The mounting bracket 11 is fixedly connected to the front panel 22 so that the light generated by the DC arc generating mechanism 1 exciting the sample passes through the light incident component 23 and then enters between the front panel 22 and the rear reflector 25, and enters the detector 27 for analysis after being reflected multiple times by the holographic grating 24 and the rear reflector 25. Among them, the rear reflector 25 is a spherical mirror, and the side of the spherical mirror facing the front panel 22 is concave, so that the rear reflector 25 of this application forms a vertical symmetric spectroscopic system. The vertical symmetric spectroscopic system can effectively eliminate coma, has small astigmatism, and because of the optical axis symmetry, it is easier to measure and control the incident angle and reflection angle, and at the same time reduces additional light scattering. Therefore, the spectral line wavelength is clear and has high sharpness.

[0051] Further, in this embodiment, the spectral analysis mechanism 2 further includes a window baffle 26. The window baffle 26 is an alloy aluminum plate, which is fixedly connected to the rear reflector 25. The window baffle 26 is sequentially provided with a first reflective window 261 and a second reflective window 262 in the vertical direction. The positions of the first reflective window 261 and the second reflective window 262 are set according to actual needs. The position where the first reflective window 261 is opened can receive the light passing through the light incident component 23 and reflect the incident light to the holographic grating 24 through the reflector 25. The position where the second reflective window 262 is opened can receive the light reflected by the holographic grating 24 and be reflected to the detector 27 again through the rear reflector 25. Among them, the shape of the first reflective window 261 is the same as that of the holographic grating 24, the height of the second reflective window 262 is the same as that of the holographic grating 24, and the length of the second reflective window 262 is the same as that of the detector 27. Through the settings of the first reflective window 261 and the second reflective window 262, the light will not interfere with each other during reflection, so that the light is fully reflected, thereby improving the intensity of the spectral line.

[0052] Furthermore, this application adopts the method of grating spectroscopy. Traditional spectrographs usually adopt prism spectroscopy. The required spectroscopic optical path of a prism spectroscopic spectrograph is relatively long, and the resolution is affected by the optical path and is relatively low. Moreover, the intensity of the spectral line is severely lost after passing through the prism, and the detection result is inaccurate. Grating spectroscopy includes a vertical symmetric spectroscopy system and a Rowland circle spectroscopy system. In the Rowland circle spectroscopy system, the detector receiving surface is on an arc, the distance between the spectral plane and the grating is inconsistent, and the clarity of different wavelengths is different. It is difficult to present a clear image for spectral lines with relatively low intensity. Therefore, a vertical symmetric spectroscopy system is adopted in this application. Among them, the holographic grating 24 is a grating made by holographic technology, which can record the amplitude and phase information of light waves, so as to produce a three-dimensional image effect during reproduction. The CCD detector can convert the dispersed spectrum into a digital signal, which is convenient for intuitive and accurate analysis.

[0053] Most traditional grating spectrometers use mechanically ruled blazed gratings and concave gratings. Mechanically ruled gratings have a blazed wavelength (i.e., the cutting angle of the grating rulings on the grating substrate). Within the range of its adapted blazed wavelength, most spectral lines can be imaged clearly and sharply. However, for spectral lines outside the blazed wavelength range, the clarity is relatively low. Therefore, the spectral line wavelength coverage range is severely limited, and it is difficult to achieve clear spectral line wavelengths over a large range. For example, for a blazed grating with a blazed wavelength of 300 nm, the range where the spectral lines are relatively clear is approximately 250 nm - 350 nm. When the spectral line wavelength exceeds this range, it is difficult to be imaged clearly and sharply, which affects the accuracy of the analysis results. To increase the number of elements for analysis, that is, more spectral line wavelengths are required, so a wider coverage range is needed, and on the premise of a wider coverage range, the clarity of the spectral lines is good. The concave grating uses the Rowland circle spectroscopic system, so it is also called the Rowland grating. Its advantage is that the required spectroscopic chamber is relatively small, and direct spectroscopy can be achieved without a reflector. The disadvantages are coma and astigmatism. Coma distorts the spectral lines, and in severe cases, low-intensity spectral lines cannot be distinguished, which may lead to misjudgment or omission of some weak spectral lines. Astigmatism means there are differences in the clarity and focusing position of the image, which will cause uneven imaging and different intensities of the spectral lines on the detector, thus affecting the analysis results. At the same time, the manufacturing cost of concave gratings is high.

[0054] Compared with traditional grating spectrometers, the holographic grating used in this application is irradiated onto the grating substrate through holographic imaging technology, presenting vertical lines on the grating substrate with high density and uniformity. After exposure by holographic imaging irradiation, the rulings on the grating surface are achieved by controlling the degree of corrosion. Compared with mechanically ruled gratings, the rulings of the holographic grating are clear, of the same depth, and have uniform gaps, with almost no ruling number error. The cutting angles on the holographic grating substrate are the same, and there is no problem of blazed wavelength. Therefore, within the full spectral line range, the spectral lines can be imaged clearly and sharply, which can improve the effect of reflected light in the vertical spectroscopic system, and thus improve the accuracy of the detection results.

[0055] Specifically, the light incident component 23 includes a light incident tube 231 and a slit member 232. The light incident tube 231 separates stray light and focuses the excitation light source onto the slit, such that the light intensity entering the slit is maximized. The light incident tube 231 is fixedly connected to the front panel 22 through the slit member 232. After the light enters the light incident tube 231, the light quantity is changed by the slit member 232 and then emitted. The light incident tube 231 is fixedly connected to the front panel 22 through the slit member 232. The center of the top of the holographic grating 24 is connected to the front panel 22 through a connecting frame and is located below the slit member 232. Specifically, the holographic grating 24 is fixedly connected to the bottom of the connecting frame. The holographic grating 24 can rotate about an axis in the vertical direction through the connecting frame, that is, the central axis of the holographic grating 24 and the rotation axis of the connecting frame are on the same axis. A rotation adjusting member is fixedly installed on one side of the front panel 22 close to the rear reflector 25. The rotation adjusting member can adopt a commonly used angle adjusting mechanism in the art, such as a stepper motor. The output end of the rotation adjusting member is arranged vertically and the end is connected to the connecting frame, and the output end of the rotation adjusting member is coaxially arranged with the rotation axis of the connecting frame. The rotation adjusting member can drive the holographic grating 24 to rotate, thereby adjusting the light reflection angle. The rotation adjusting member can drive the connecting frame and the holographic grating 24 to rotate, thereby adjusting the light reflection route, so that the light is accurately reflected onto the detector 27. During the adjustment process of the rotation adjusting member, the height and the position in the horizontal direction of the holographic grating 24 remain unchanged, and only the angle deflection is realized.

[0056] In the traditional spectrograph, the grating rotation angle is fixed during operation, that is, the central wavelength is fixed. However, the physical distance of the detection window of the spectrograph is limited, and the single-shot spectral coverage range is relatively narrow, usually only about 80 nm. If it is desired to cover other different wavelength bands again, the position of the central wavelength needs to be readjusted to achieve it. In this application, the angle of the holographic grating 24 is adjusted by a rotation adjusting member such as a stepper motor, and the coverage of spectral line wavelengths in different ranges can be realized. Combining with the data processing system, the spectra obtained from multiple scans are data-reorganized. Specifically, when the grating is at different rotation angles, the corresponding central wavelengths are different (the central wavelength is the center point of the detected wavelength range. For example, when the detection coverage range is 250 nm - 330 nm, the central wavelength is 290 nm). The stepper motor is used to drive the grating to change the grating rotation angle, so as to collect spectral lines with different central wavelengths during the spectral analysis process (for example, collect spectral lines of 240 nm - 330 nm at one time, and collect spectral lines of 330 nm - 410 nm after rotating the grating rotation angle). In addition, a baffle is fixedly connected to the top of the holographic grating 24. The light incident from the light incident tube 231 is located above the baffle, and the baffle is used to prevent interference between the incident light and the light reflected by the holographic grating 24.

[0057] More specifically, the slit member 232 includes a fixed box and two slit blocks (not shown in the figure). The fixed box is fixedly connected through the front panel 22. The light inlet tube 231 is fixedly connected to and communicated with the fixed box. Both slit blocks are slidably connected to the inner wall of the fixed box to approach or move away from each other. The two slit blocks are connected by an elastic member. In this embodiment, the elastic member is a spring. After the light passes through the light inlet tube 231, it emits from between the two slit blocks. The slit member 232 further includes an adjusting member for driving the two slit blocks to move away from each other. In this embodiment, the adjusting member is a threaded ejector rod. The threaded ejector rod is threadedly connected to the fixed box and the diameter of the end located inside the fixed box gradually changes from small to large. Connection blocks 134 are fixedly connected to both slit blocks. A gap for the threaded ejector rod to insert is left between the two connection blocks 134. By rotating the threaded ejector rod, the end extends between the two slit blocks to push the two slit blocks away from each other, thereby increasing the slit spacing.

[0058] Furthermore, to adjust the position of the rear reflector 25, a fine-tuning drive assembly 28 for driving the rear reflector 25 to move is provided on the base 21. The fine-tuning drive assembly 28 includes a fixed seat 281, a screw 282, and a nut 283. The fixed seat 281 is fixedly connected to the base 21. The screw 282 is rotatably connected to the fixed seat 281 and its axis is arranged along the moving direction of the rear reflector 25. The nut 283 is fixedly connected to the bottom of the rear reflector 25 and is threadedly connected to the screw 282. Rotating the screw 282 can drive the nut 283 and the rear reflector 25 to move. To improve the sliding stability of the rear reflector 25, two guiding sliders 211 are fixedly connected to the base 21. The guiding sliders 211 are precision guiding sliders to improve the translational stability of the reflector 25. The two guiding sliders 211 are arranged symmetrically left and right. The rear reflector 25 is slidably connected to both guiding sliders 211. The sliding direction of the rear reflector 25 is perpendicular to the front panel 22. In a traditional plane grating spectrograph, to adjust the optical distance between the slit and the CCD detector, a movable tube-shaped mechanical structure is usually selected at the position of the slit, so that the slit can be translated horizontally. Due to its complex mechanical structure, many components, it is easy to generate more mechanical errors, and the adjustment stroke is long. After frequent adjustment, the mechanical wear is serious, resulting in errors, reducing the adjustment accuracy. And because the slit assembly is on its adjustment mechanical structure, after long-term use, problems such as the slit tilting and offset occur; in this application, by moving the reflector 25, the physical distance between the slit and the rear reflector 25 is adjusted, so as to change the optical distance between the slit and the CCD detector, so as to make the optical distance between the slit and the CCD detector equal to the focal length of the rear reflector 25. This adjustment method will not cause any impact on the slit assembly, and ensure the stability of the rear reflector 25 in the vertical and horizontal directions during the adjustment process.

[0059] By changing the physical position of the rear reflector 25 in the spectroscopic optical system, this application enables the spectral lines to have an optical path of incidence and reflection twice on the rear reflector 25. During the adjustment process, the incident light and the reflected light are adjusted simultaneously. Therefore, the physical adjustment distance can be shortened by half, greatly simplifying the focusing method and improving the adjustment efficiency. Moreover, the adjustment mechanical structure is independent and will not affect other mechanical structures and components during the adjustment process. In practical applications, the spectral lines are clear and sharp, effectively improving the accuracy of the analysis results. At the same time, the light source irradiates the upper part of the spherical mirror through the slit. This part acts as a collimating mirror. The parallel light beam emitted by the collimating mirror irradiates the grating. After being spectroscopically dispersed by the grating, it irradiates the lower part of the concave mirror. This part acts as a photographic objective lens. The CCD detector is placed on the rubber surface of the spherical mirror. The advantage of this optical system is that it can effectively eliminate the coma at the center of the field of view and reduce the coma at the edge of the field of view, and the astigmatism is also very small. Therefore, the characteristic spectral lines are imaged clearly and sharply, symmetric left and right, compact in structure, and low in cost.

[0060] Embodiment 2:

[0061] Referring to Figure 4 , the difference between this embodiment and Embodiment 1 is that a connecting plate 29 is fixedly connected to one end of the base 21 close to the front panel 22. The connecting plate 29, the base 21, and the bottom plate 111 are on the same straight line. A connecting groove for inserting the connecting plate 29 is opened at one end of the bottom plate 111 away from the column 112. A plurality of first connecting holes are opened along the length direction on the connecting plate 29, and a second connecting hole is opened on the bottom plate 111. Bolts are used to pass through the first connecting hole and the second connecting hole to fix the relative positions of the connecting plate 29 and the bottom plate 111, so as to be able to adjust the distance from the sample-emitted light to the front panel 22, improving the applicability of this application; and this device can be disassembled and stored during transportation, and is also convenient for installation and use.

[0062] It should be understood that expressions such as "including" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit the existence of one or more additional functions, operations, and constituent elements. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or a combination thereof.

[0063] It should be understood that the orientation or positional relationships indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0064] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0065] In the present application, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0066] Those skilled in the art can easily understand that the above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A holographic grating direct current emission spectrometer, characterized in that, It comprises an integrated DC arc generating mechanism (1) and a spectrum analyzing mechanism (2); The spectrum analysis mechanism (2) comprises a base (21), a front panel (22), a light-incoming assembly (23), a holographic grating (24), a rear reflector (25) and a detector (27); the front panel (22) is fixedly connected to one end of the base (21); the light-incoming assembly (23), the holographic grating (24) and the detector (27) are all arranged on the front panel (22); the rear reflector (25) is slidably connected to the base (21) to move closer to or farther away from the detector (27); and the rear reflector (25) is a spherical reflector. The DC arc generating mechanism (1) is arranged at one end of the base (21) close to the front panel (22) so as to allow the light generated by the excited sample to pass through the light input component (23) and enter between the front panel (22) and the rear reflector (25), and then enter the detector (27) after being reflected by the holographic grating (24) and the rear reflector (25).

2. The holographic grating direct emission spectrometer according to claim 1, wherein The DC arc generating mechanism (1) comprises a mounting frame (11) and two electrode clamps (12) arranged symmetrically in an upper and lower direction, wherein the two electrode clamps (12) are both arranged on the mounting frame (11); The mounting frame (11) includes a horizontally arranged bottom plate (111) and a vertically arranged column (112), wherein the bottom plate (111) is fixedly connected to one end of the base (21) close to the front panel (22), and the bottom plate (111) and the base (21) are located on the same straight line, and the column (112) is fixedly connected to one end of the bottom plate (111) away from the base (21); the DC arc generating mechanism (1) also includes a mounting member, and the two electrode clamps (12) are both detachably connected to the column (112) via the mounting member, and the positions of the two electrode clamps (12) are adjustable.

3. The holographic grating direct current emission spectrometer according to claim 2, characterized in that, The mounting member is an integrated structure or includes two sub-mounting members (13), and the two sub-mounting members (13) are respectively connected to corresponding electrode clamps (12).

4. The holographic grating direct current emission spectrometer according to claim 3, characterized in that, The sub-mounting member (13) includes a mounting block (131), a threaded locking member (132), a connecting rod (133) and a connecting block (134); the mounting block (131) is provided with a through hole (1311) for the column (112) to pass through; the threaded locking member (132) is threadedly connected to the mounting block (131) and one end extends into the through hole (1311); one end of the connecting rod (133) is fixedly connected to the mounting block (131) and the other end is fixedly connected to the connecting block (134); the connecting block (134) is provided with a slot (1341) for mounting the electrode clamp (12).

5. A holographic grating direct current emission spectrometer according to any one of claims 1-4, characterized in that, The DC arc generating mechanism (1) further comprises a DC arc energizer, and the DC arc energizer is electrically connected to the two electrode clamps (12) respectively.

6. The holographic grating direct current emission spectrometer according to claim 1, wherein The light intake assembly (23) comprises a light intake tube (231) and a slit member (232). The light intake tube (231) is fixedly connected to the front panel (22) via the slit member (232). After light enters the light intake tube (231), the amount of light entering the light is changed by the slit member (232) and then emitted.

7. The holographic grating direct current emission spectrometer according to claim 6, characterized in that, The holographic grating (24) is connected to the front panel (22) and is located below the slit member (232). The holographic grating (24) can rotate about the central axis in its vertical direction as the rotation axis.

8. The holographic grating direct current emission spectrometer according to claim 7, characterized in that, The spectral analysis mechanism (2) further includes a window baffle (26). The window baffle (26) is disposed on the rear reflector (25) and is provided with a first reflective window (261) and a second reflective window (262) in sequence along the vertical direction. After the light passes through the first reflective window (261), the incident light is reflected by the rear reflector (25) to the holographic grating (24). The light reflected by the holographic grating (24) passes through the second reflective window (262) and is reflected by the rear reflector (25) again to the detector (27).

9. The holographic grating direct current emission spectrometer according to claim 1, wherein, A fine-tuning drive assembly (28) for driving the movement of the rear reflector (25) is provided on the base (21). The movement direction of the rear reflector (25) is the same as the light incident direction of the DC arc generating mechanism (1).

10. A holographic grating direct-current emission spectrometer according to claim 9, characterized in that, The fine-tuning drive assembly (28) includes a fixed seat (281), a screw (282), and a nut (283). The fixed seat (281) is fixedly connected to the base (21). The screw (282) is rotatably connected to the fixed seat (281) and its axis is arranged along the movement direction of the rear reflector (25). The nut (283) is fixedly connected to the bottom of the rear reflector (25) and is threadedly connected to the screw (282).

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