CN116223479A - LIBS spectrum detection system with waste gas recovery function based on sub-femtosecond stripe camera - Google Patents
LIBS spectrum detection system with waste gas recovery function based on sub-femtosecond stripe camera Download PDFInfo
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Abstract
The invention discloses a LIBS spectrum detection system with an exhaust gas recovery function based on a sub-femtosecond stripe camera, which comprises the following components: a femtosecond high-energy pulse laser emits laser light; the beam splitter splits the laser; the delay system synchronously operates the femtosecond high-energy pulse laser and the stripe tube detector at the same time; the streak tube detector forms a spectral signal with high time resolution; reflecting laser to the reflecting telescope by the medium film reflecting mirror; focusing a laser pulse signal to a sample chamber by a reflective telescope, and collecting an echo signal of a sample; the optical focusing lens focuses the echo signals to the optical fiber; the optical fiber emits an optical signal to the grating beam-splitting prism; the grating light splitting system separates the optical signals; the cylindrical focusing lens focuses the spectrum signal and transmits the spectrum signal to the photoelectric cathode of the stripe tube detector; the ICCD amplifies the time-resolved spectrum signal; the computer processes the spectral information and performs an analysis. Can avoid the pollution of pollutants to the surrounding environment in the experimental process.
Description
Technical Field
The invention belongs to the technical field of spectrum detection, and particularly relates to a LIBS spectrum detection system with an exhaust gas recovery function based on a sub-femtosecond stripe camera.
Background
Due to the rapid development of industrial technology, the global environment situation is increasingly severe, and particularly, the atmospheric environment is polluted, and haze becomes a special landscape of developed cities, so that the real-time understanding of the atmospheric environment quality and the prediction of the environmental quality development are vital to the production and life of human beings. Atmospheric environmental pollution mainly comes from smoke dust discharged from industrial production, processing processes, various boilers or cooking ranges, pollutants discharged from automobiles, secondary pollutants converted by the smoke dust, and the like. Therefore, detection and tracing of pollutants such as smoke in the atmosphere, a large number of very fine dry dust particles such as aerosol particles, photochemical smog and the like has important research value.
The laser-induced breakdown spectroscopy (Laser Induced Breakdown Spectroscopy, LIBS) is a detection method for elemental analysis of solid, liquid, gas and aerosol state substances, and has the advantages of no need of sample treatment, simple operation, non-destructive detection approximation, multi-element detection, no secondary pollution of excited samples, and the like. There are many specialists applying the LIBS technology to the detection of atmospheric environmental quality. Currently, the LIBS basically adopts a photomultiplier tube or ICCD to acquire a spectrum, and can acquire a time resolution spectrum by controlling the time of a gating shutter, but the method has the defects of low time resolution, long measurement time and the like.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond stripe camera, realizes LIBS spectrum detection with the waste gas recovery function based on the sub-femtosecond time resolution and large detection range stripe tube, can provide a high time resolution fingerprint image, and has high measurement speed and high sensitivity.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a LIBS spectrum detection system with an exhaust gas recovery function based on a sub-femtosecond stripe camera comprises a femtosecond high-energy pulse laser, a beam splitter, a delay system, a sub-femtosecond stripe tube detector, a dielectric film reflector, a reflective telescope, a sample chamber, an exhaust gas recovery device, an optical focusing lens, an optical fiber, a grating beam splitting system, a cylindrical focusing lens, an ICCD and a computer system;
the femtosecond high-energy pulse laser is used for emitting femtosecond high-energy pulse laser with a required wavelength;
the beam splitter is used for splitting the femtosecond high-energy pulse laser;
the delay system is used for synchronizing the simultaneous working of the femtosecond high-energy pulse laser and the stripe tube detector;
the stripe tube detector is used for receiving the optical signal after passing through the grating beam splitting prism and converting the input high-speed time signal into a low-speed space signal to form a spectrum signal with high time resolution;
the dielectric film reflector is used for reflecting the femtosecond high-energy pulse laser after passing through the beam splitter to the reflecting telescope;
the reflecting telescope is used for focusing the laser pulse signals reflected by the dielectric film reflecting mirror to the sample chamber and collecting echo signals of the sample;
the outside of the sample chamber and the waste gas recovery device is opposite to the reflective telescope;
an optical focusing lens for focusing the echo signal to the optical fiber;
the optical fiber is used for emitting the focused optical signals to the grating beam-splitting prism;
the grating light splitting system is used for spatially separating optical signals with different wavelengths;
the cylindrical focusing lens is used for focusing the spectrum signal output by the grating light-splitting system into a bit signal and transmitting the bit signal to the photoelectric cathode of the stripe tube detector;
ICCD, is used for amplifying the weak time-resolved spectrum signal;
and the computer is used for processing the spectrum information and analyzing the spectrum information.
In order to optimize the technical scheme, the specific measures adopted further comprise:
the femtosecond high-energy pulse laser is a high-power high-energy femtosecond laser, the output pulse laser wavelength is 515nm/343nm/257nm/206nm, and the energy is 1 mJ-200 mJ level; the pulse width of 20 fs-50 fs is adjustable.
The strip tube detector is a sub-femtosecond time resolution strip tube with a large detection range, and comprises a photocathode, an acceleration system, a time focusing system, an anode system, a scanning deflection system, a space focusing system and a fluorescent screen which are sequentially arranged;
the photocathode is used for converting an external optical image into an electronic image;
an acceleration system for accelerating the electron image emitted by the photocathode;
a time focusing system for focusing the electronic image in a time direction;
an anode system for accelerating electrons, removing large-angle electrons, and collimating an electron image;
a scanning deflection system for converting time information of the electronic image output from the anode system into spatial information;
the space focusing system is used for focusing the electronic image of the emergent scanning deflection system along the space direction;
a phosphor screen for converting the electronic image after focusing by the spatial focusing system into a visible optical image.
The photocathode is a planar photocathode;
the accelerating system is a high-precision grid structure accelerating system and comprises a planar high-precision grid structure, wherein an electron diffusion preventing upper polar plate and an electron diffusion preventing lower polar plate which are arranged at the rear end part of the high-precision grid structure and are arranged along the space direction are arranged in parallel;
the time focusing system is a flat-plate focusing system and comprises two parallel plates which are symmetrically arranged, and the first parallel plate and the second parallel plate adopt cuboid structures;
the anode system is of a flat plate structure, an electron inlet of the anode system is an upper polar plate of a parallel plate structure and a lower polar plate of the parallel plate structure, a first baffle structure which is mutually perpendicular to the upper polar plate of the parallel plate structure is arranged at an electron outlet, and a second baffle structure which is mutually perpendicular to the lower polar plate of the parallel plate structure is arranged at the electron outlet;
the width of the slit between the first baffle structure and the second baffle structure is adjustable;
the scanning deflection system is a flat-plate scanning deflection system and comprises an upper polar plate and a lower polar plate which are symmetrically arranged up and down, and an electron inlet of the scanning deflection system is close to a slit between the first baffle structure of the anode and the second baffle structure of the anode;
the space focusing system is a single lens focusing system and comprises a first focusing electrode upper plate and a first focusing electrode lower plate which are sequentially arranged along the electron propagation direction and have the same distance from an optical axis and the same axial length, a second focusing electrode upper plate and a second focusing electrode lower plate, and a third focusing electrode upper plate and a third focusing electrode lower plate;
the first focusing electrode upper polar plate and the first focusing electrode lower polar plate are arranged in parallel, the second focusing electrode upper polar plate and the second focusing electrode lower polar plate are arranged in parallel, and the third focusing electrode upper polar plate and the third focusing electrode lower polar plate are arranged in parallel.
The photocathode, the accelerating system, the time focusing system, the anode system, the scanning deflection system, the space focusing system and the fluorescent screen are sequentially connected through a ceramic ring or a glass ring;
the planar high-precision grid structure of the accelerating system is electrically connected with the upper electrode plate for preventing electron diffusion and the lower electrode plate for preventing electron diffusion;
the upper polar plate of the parallel plate structure of the anode system is electrically connected with the first baffle structure, and the lower polar plate of the parallel plate structure is electrically connected with the second baffle structure;
the upper electrode plate of the first focusing electrode, the upper electrode plate of the second focusing electrode and the upper electrode plate of the third focusing electrode of the space focusing system are sequentially connected through a ceramic ring or a glass ring, and the lower electrode plate of the first focusing electrode, the lower electrode plate of the second focusing electrode and the lower electrode plate of the third focusing electrode are sequentially connected through a ceramic ring or a glass ring.
The effective imaging range of the photocathode of the strip tube detector is 4mm multiplied by 40 mu m;
the space length of the one-dimensional optical signal focused by the cylindrical focusing lens is smaller than 4mm, and the width is smaller than 4 mu m;
the distance between the upper polar plate for preventing the electron diffusion of the accelerating system and the lower polar plate for preventing the electron diffusion of the accelerating system is 9 mm-13 mm; the length along the optical axis direction is 9 mm-13 mm;
the front end parallel plate of the anode system has an upper polar plate and a lower polar plate with a parallel structure with a distance of 2 mm-5 mm, a width of 30 mm-40 mm and a length of 20 mm-28 mm along the optical axis direction; the rear end is provided with a first baffle structure and a second baffle structure, and the interval between the first baffle structure and the second baffle structure is 5-50 mu m;
the first focusing electrode upper electrode plate, the first focusing electrode lower electrode plate, the second focusing electrode upper electrode plate and the second focusing electrode lower electrode plate are respectively arranged at intervals of 10 mm-30 mm; the dimension along the length direction of the optical axis is 30 mm-40 mm; the thickness is 0.5mm;
the radius of the fluorescent screen is 15-25 mm.
The potential difference between the photocathode and the accelerating system is 10 kV-16 kV;
the potential difference between the time focusing system and the anode system is 8 kV-13 kV;
the potential difference between the fluorescent screen and the space focusing system is 6 kV-11 kV;
the electric potential between the first focusing electrode upper polar plate, the first focusing electrode lower polar plate, the third focusing electrode upper polar plate and the third focusing electrode lower polar plate is 0V, and the electric potential difference between the first focusing electrode upper polar plate and the second focusing electrode upper polar plate is 3 kV-5 kV.
The sample chamber and the exhaust gas recovery device include: the device comprises a device body, a sample placing turntable, a sample supporting rod, a sample placing groove, a flange, a first waste gas recovery device, a second waste gas recovery device, a firing source device and a combustion improver storage device;
the device comprises a device body, a plurality of flanges, a combustion improver device, a sample placing device, a fire source device, a combustion improver device, a plurality of flanges, a plurality of fire source devices, a plurality of combustion improver devices and a plurality of fire source devices, wherein the flanges are arranged on the outer wall of the device body; the other two flanges are used for being connected with the first waste gas recovery device and the second waste gas recovery device;
the device body is connected with the sample placing turntable through a sample supporting rod;
the sample placing turntable can rotate 0-360 degrees along the horizontal direction;
the sample placing groove can rotate anticlockwise by 0-45 degrees;
the sample placing groove is a groove type sample holder and is used for placing a sample;
the sample support is provided with a hole with the size of the laser beam spot for spectrum detection.
The ignition source placing device and the combustion improver placing device are connected with the sample chamber through the flange in the initial stage of the experiment, and are isolated through the flange before and after the experiment;
the first waste gas recovery device and the second waste gas recovery device are isolated from the sample chamber through flanges in the experimental stage;
when LIBS detection is needed to be carried out on the combustion ashes, the sample tray is started to rotate anticlockwise for 30-45 degrees.
The invention has the following beneficial effects:
1. the LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond time resolution and large detection range stripe tube utilizes the unique sub-femtosecond time resolution and large detection range stripe tube as a spectrum receiving detection device, and can provide a femtosecond time resolution 'spectrum fingerprint' by converting ultra-high speed time information into low-speed space information, and meanwhile, the LIBS spectrum detection system has the advantages of high response speed and high sensitivity.
2. The LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond time resolution and large detection range strip tube provides a waste gas treatment function, and avoids pollution of pollutants to the surrounding environment in the experimental process;
3. the LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond time resolution and the large detection range strip tube provided by the invention provides a sample chamber and a waste gas recovery device, and can carry out spectrum detection on solid, liquid, gas and aerosol state substances; the advantages are that the gas (including the gas generated by combustion) is not easy to diffuse and has high concentration.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram of a sub-femtosecond level large detection range streak tube structure;
FIG. 3 is a schematic diagram of an acceleration system configuration;
FIG. 4 is a schematic diagram of a spatial focusing system configuration;
the reference numerals are as follows:
the device comprises a 1-femtosecond high-energy pulse laser, a 2-beam splitter, a 3-delay system, a 4-stripe tube detector, a 5-dielectric film reflector, a 6-reflecting telescope, a 7-sample chamber and an exhaust gas recovery device, an 8-optical focusing lens, a 9-optical fiber, a 10-grating beam splitter system, an 11-cylindrical focusing lens, a 12-ICCD and a 13-computer system;
41-photocathode, 42-accelerating system, 43-time focusing system, 44-anode system, 45-scanning deflection system, 46-space focusing system, 47-fluorescent screen;
421-plane high-precision grid structure, 422-upper electrode plate for electron diffusion and 423-lower electrode plate for electron diffusion prevention;
431-first parallel plate, 432-second parallel plate;
441-upper plate structure, 442-lower plate structure, 443-first baffle structure, 444-second baffle structure;
451-upper polar plate, 452-lower polar plate;
4611-a first focusing electrode upper plate, 4612-a first focusing electrode lower plate, 4621-a second focusing electrode upper plate, 4622-a second focusing electrode lower plate, 4631-a third focusing electrode upper plate, 4632-a third focusing electrode lower plate;
the device comprises a sample 71-part, a sample placing groove 72-part, a firing source device 73-part, a first waste gas recovery device 74-part, a combustion improver accommodating device 75-part, a first waste gas recovery device 76-part, a flange 77-part, a sample placing turntable 78-part and a sample supporting rod 79-part.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Although the steps of the present invention are arranged by reference numerals, the order of the steps is not limited, and the relative order of the steps may be adjusted unless the order of the steps is explicitly stated or the execution of a step requires other steps as a basis. It is to be understood that the term "and/or" as used herein relates to and encompasses any and all possible combinations of one or more of the associated listed items.
As shown in fig. 1, the LIBS spectrum detection system with the waste gas recovery function based on the sub-femto-second fringe camera comprises a femto-second high-energy pulse laser 1, a beam splitter 2, a delay system 3, a sub-femto-second fringe tube detector 4, a dielectric film reflector 5, a reflecting telescope 6, a sample room and waste gas recovery device 7, an optical focusing lens 8, an optical fiber 9, a grating beam splitting system 10, a cylindrical focusing lens 11, an ICCD12 and a computer system 13;
the femtosecond high-energy pulse laser 1 is used for emitting femtosecond high-energy pulse laser with a required wavelength; a solid-state pulse laser with an output light pulse wavelength of 532nm may be used. Other types of pulsed lasers, such as carbon dioxide lasers, laser diode arrays, etc., may also be employed.
A beam splitter 2 for splitting the femtosecond high-energy pulse laser;
the delay system 3 is used for synchronously working the femtosecond high-energy pulse laser 1 and the streak tube detector 4 at the same time;
the stripe tube detector 4 is used for receiving the optical signal after passing through the grating beam splitting prism 10 and converting the input high-speed time signal into a low-speed space signal to form a spectrum signal with high time resolution;
a dielectric film reflector 5 for reflecting the femtosecond high energy pulse laser after passing through the beam splitter 2 to a reflective telescope 6;
a reflective telescope 6 for focusing the laser pulse signal reflected by the dielectric film mirror 5 to the sample chamber 7 and collecting the echo signal of the sample;
the outside of the sample chamber and the waste gas recovery device 7 is opposite to the reflection telescope 6;
an optical focusing lens 8 for focusing the echo signal to an optical fiber 9;
an optical fiber 9 for outputting the focused optical signal to a grating beam-splitting prism 10;
a grating light-splitting system 10 for spatially separating optical signals of different wavelengths;
a cylindrical focusing lens 11 for focusing the spectrum signal outputted from the grating beam-splitting system 10 into a bit signal and transmitting the bit signal to the photocathode of the streak tube detector 4;
ICCD12, is used for amplifying the weak time-resolved spectrum signal;
and a computer 13 for processing and analyzing the spectral information.
In the embodiment, the femtosecond high-energy pulse laser 1 is a high-power high-energy femtosecond laser, the output pulse laser wavelength is 515nm/343nm/257nm/206nm, and the energy is 1 mJ-200 mJ level; the pulse width of 20 fs-50 fs is adjustable.
In an embodiment, the streak tube detector 4 is a sub-femto-second time resolution and large detection range streak tube structure, see fig. 2, 3 and 4, wherein fig. 2 is a schematic diagram of a sub-femto-second large detection range streak tube structure, fig. 3 is a schematic diagram of an acceleration system structure, and fig. 4 is a schematic diagram of a spatial focusing system structure. As can be seen from fig. 2, 3 and 4, the streak tube detector 4 includes a photocathode 41, an acceleration system 42, a time focusing system 43, an anode system 44, a scanning deflection system 45, a spatial focusing system 46 and a screen 47, which are arranged in this order;
wherein, the photocathode 41 is used for converting an external optical image into an electronic image;
an acceleration system 42 for accelerating the electron image emitted from the photocathode 41;
a time focusing system 43 for focusing the electronic image in a time direction;
an anode system 44 for accelerating electrons, removing large angle electrons, and collimating the electron image;
a scanning deflection system 45 for converting time information of the electronic image output from the anode system 44 into spatial information;
a spatial focusing system 46 for focusing the electronic image of the exit scanning deflection system 45 in a spatial direction;
a phosphor screen 47 for converting the electronic image after focusing by the spatial focusing system 46 into a visible optical image;
in an embodiment, the photocathode 41 is a planar photocathode; the radius of the planar photocathode is 18 mm-25 mm, and the radius is 20mm optionally; the dimension along the length direction of the optical axis direction is 0.05 mm-0.5 mm, and the optional dimension is 0.5mm;
the accelerating system 42 is a high-precision grid structure accelerating system, and mainly comprises a planar high-precision grid structure 421, and an electron diffusion preventing upper electrode plate 422 and an electron diffusion preventing lower electrode plate 423 which are arranged at the rear end part of the high-precision grid structure 421 and are arranged along the space direction, wherein the electron diffusion preventing upper electrode plate 422 and the electron diffusion preventing lower electrode plate 423 are arranged in parallel.
The time focusing system 43 is a flat-plate focusing system, and comprises two parallel plates which are symmetrically placed, and the first parallel plate 431 and the second parallel plate 432 adopt a cuboid structure; the dimension of the upper polar plate and the lower polar plate of the time focusing system along the length direction of the optical axis is 25 mm-32 mm, and 26mm is optional; the dimension along the space direction is 30 mm-42 mm, and 36mm is optional; the distance between the upper polar plate and the lower polar plate is 2 mm-5 mm, and 3mm is optional;
the anode system 44 has a flat plate structure, the electron inlet is an upper plate 441 of a parallel plate structure and a lower plate 442 of a parallel plate structure, a first baffle structure 443 perpendicular to the upper plate 441 of the parallel plate structure is arranged at the electron outlet, and a second baffle structure 444 perpendicular to the lower plate 442 of the parallel plate structure is arranged at the electron outlet;
the slit width between the first baffle structure 443 and the second baffle structure 444 is adjustable;
the scanning deflection system 45 is a flat-plate scanning deflection system, and comprises an upper polar plate 451 and a lower polar plate 452 which are arranged in an upper-lower symmetrical way, and an electron inlet of the upper polar plate 451 and the lower polar plate 452 is close to a slit between the anode first baffle structure 443 and the anode second baffle structure 444; the distance between two parallel plates which are arranged vertically symmetrically of the scanning deflection system is 2.5 mm-6.5 mm, and 3mm is optional; the dimension along the length direction of the optical axis is 12 mm-18 mm, and the optional dimension is 12mm; the dimension along the slit direction is 30 mm-50 mm, optionally 48mm;
the upper plate 451 and the lower plate 452 are both rectangular structures.
The space focusing system 46 is a single lens focusing system, and comprises a first focusing electrode upper plate 4611 and a first focusing electrode lower plate 4612, a second focusing electrode upper plate 4621 and a second focusing electrode lower plate 4622, and a third focusing electrode upper plate 4631 and a third focusing electrode lower plate 4632 which are sequentially arranged along the electron propagation direction and have equal distances from the optical axis and axial lengths;
the first focus electrode upper plate 4611 and the first focus electrode lower plate 4612 are placed in parallel, the second focus electrode upper plate 4621 and the second focus electrode lower plate 4622 are placed in parallel, and the third focus electrode upper plate 4631 and the third focus electrode lower plate 4632 are placed in parallel;
the first focusing electrode upper plate 4611, the first focusing electrode lower plate 4612, the second focusing electrode upper plate 4621, the second focusing electrode lower plate 4622, the third focusing electrode upper plate 4631 and the third focusing electrode lower plate 4632 are all rectangular parallelepiped electrodes.
In the embodiment, the photocathode 41, the acceleration system 42, the time focusing system 43, the anode system 44, the scanning deflection system 45, the space focusing system 46 and the fluorescent screen 47 are sequentially connected through a ceramic ring or a glass ring;
the planar high-precision grid structure 421 of the acceleration system 42 is electrically connected with the upper electrode plate 422 and the lower electrode plate 423;
the upper plate 441 of the parallel plate structure of the anode system 44 is electrically connected to the first baffle structure 443, and the lower plate 442 of the parallel plate structure is electrically connected to the second baffle structure 444;
the first upper focusing electrode plate 4611, the second upper focusing electrode plate 4621 and the third upper focusing electrode plate 4631 of the spatial focusing system 46 are sequentially connected by a ceramic ring or a glass ring, and the first lower focusing electrode plate 4612, the second lower focusing electrode plate 4622 and the third lower focusing electrode plate 4632 are sequentially connected by a ceramic ring or a glass ring.
In an embodiment, the effective imaging range of the photocathode of the streak tube detector 4 is 4mm×40 μm;
the space length of the one-dimensional optical signal after being focused by the cylindrical focusing lens 11 is smaller than 4mm, and the width is smaller than 4 mu m;
the distance between the upper polar plate 422 for preventing the electron diffusion of the accelerating system and the lower polar plate 423 for preventing the electron diffusion of the accelerating system is 9 mm-13 mm; the length along the optical axis direction is 9 mm-13 mm; in specific implementation, the method can also comprise the following steps: the radius of the acceleration system is 18 mm-25 mm, and the optional radius is 20mm; the dimension along the length direction of the optical axis is 0.05 mm-0.1 mm, and the optional dimension is 0.05mm; the middle slit is arranged along the slit direction, and the size is 10mm multiplied by 10 mu m;
the front end parallel plate structure upper polar plate 441 and the parallel plate structure lower polar plate 442 of the anode system 44 have a distance of 2 mm-5 mm, a width of 30 mm-40 mm, and a length of 20 mm-28 mm along the optical axis direction; the rear end is provided with a first baffle structure 443 and a second baffle structure 444, and the interval between the first baffle structure 443 and the second baffle structure 444 is 5 mu m-50 mu m; in specific implementation, the method can also comprise the following steps: the size of the parallel plate structure at the front end of the anode system along the length direction of the optical axis is 20 mm-28 mm, and 22mm is optional; the dimension along the space direction is 30 mm-40 mm, and 36mm is optional; the distance between the upper polar plate and the lower polar plate is 2 mm-5 mm, and 3mm is optional; the size of the baffle plate with the rear end perpendicular to the optical axis along the length direction of the optical axis is 0.01 mm-0.2 mm, and the optional size is 0.1mm; the size of the baffle plate along the space direction is 30 mm-40 mm, and 36mm is optional; the distance between the upper polar plate and the lower polar plate is 5-50 μm and is adjustable, and the distance is 10 μm;
the first focusing electrode upper plate 4611, the first focusing electrode lower plate 4612, the second focusing electrode upper plate 4621 and the second focusing electrode lower plate 4622, and the intervals between the third focusing electrode upper plate 4631 and the third focusing electrode lower plate 4632 are all 10 mm-30 mm; the dimension along the length direction of the optical axis is 30 mm-40 mm; the thickness is 0.5mm;
the radius of the fluorescent screen 47 is 15-25 mm, optionally 20mm; the thickness is 0.1 mm-0.5 mm, optionally 0.5mm.
In an embodiment, the potential difference between the photocathode 41 and the acceleration system 42 is 10 kV-16 kV; the potential difference between the photocathode and the accelerating electrode is 10 kV-16 kV, and 15kV is optional; the potential difference between the time focusing system and the accelerating electrode is 3 kV-8 kV, and 5kV is optional;
the potential difference between the time focusing system 43 and the anode system 44 is 8 kV-13 kV;
the potential difference between the fluorescent screen 47 and the space focusing system 46 is 6 kV-11 kV;
the potential difference between the fluorescent screen 47 and the anode system 44 is 3 kV-6 kV, optionally 5kV;
the potentials of the anode system 5, the first focus electrode upper plate 611, the first focus electrode lower plate 612, the third focus electrode upper plate 631, and the third focus electrode lower plate 632 are 0V.
The electric potential between the first focusing electrode upper polar plate 4611, the first focusing electrode lower polar plate 4612, the third focusing electrode upper polar plate 4631 and the third focusing electrode lower polar plate 4632 is 0V, and the electric potential difference between the first focusing electrode upper polar plate 4611 and the second focusing electrode upper polar plate 4621 is 3 kV-5 kV.
The potential difference between the second focusing electrode upper plate 4621 and the second focusing electrode lower plate 4622 and the anode system 44 is 3kV to 5kV, optionally 4.4kV.
In an embodiment, the sample chamber and the exhaust gas recovery apparatus 7 include: the device comprises a device body, a sample placing turntable 78, a sample supporting rod 79, a sample 71, a sample placing groove 72, a flange 77, a first waste gas recovery device 74, a second waste gas recovery device 76, an ignition source device 73 and a combustion improver containing device 75;
wherein, the number of the flanges 77 is a plurality and the flanges are arranged on the outer wall of the device body, one flange is used for being connected with the ignition source device 73, one flange is used for being connected with the combustion improver device 75, and one flange is used for placing samples; two further flanges for connection with a first exhaust gas recovery means 74 and a second exhaust gas recovery means 76;
the device body is connected with a sample placing turntable 78 through a sample supporting rod 79;
the sample placing turntable 78 can rotate 0 to 360 degrees in the horizontal direction;
the sample placement groove 72 can be rotated counterclockwise by 0 to 45 degrees;
the sample placing groove 72, i.e. the sample holder, is a groove type for placing a sample;
the sample support is provided with a hole with the size of the laser beam spot for spectrum detection.
In an embodiment, the ignition source placing device 73 and the combustion improver placing device 75 are connected with the sample chamber 7 through the flange 77 in the initial stage of the experiment, and are isolated through the flange 77 before and after the experiment;
the first waste gas recovery device 74 and the second waste gas recovery device 76 are isolated from the sample chamber 7 by a flange 77 in the experimental stage;
when LIBS detection of the burning ashes is required, the sample tray 72 is started to rotate counterclockwise by 30-45 degrees.
The LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond time resolution and the large detection range strip tube comprises the following specific working processes:
the femtosecond high-energy pulse laser 1 emits 1064nm pulse laser (can output pulsed laser of 532nm,355nm and 266nm through frequency multiplication according to actual needs, the output energy is adjustable, the maximum output energy is about 1000 mJ), the pulsed laser enters a dielectric film reflector 5 through a beam splitter 2, one beam of the pulsed laser enters the surface of a sample 71 (such as plasma, ash and the like) of a sample chamber 7 through a reflective telescope 6, a flange 77 connected with the sample chamber by a fire source device 73 and a flange 77 connected with a combustion improver device 75 and the sample chamber are simultaneously opened, two flanges are immediately closed after the sample burns, and the other beam of the pulsed laser enters a delay system 3 to trigger a stripe tube 4 to work, and the stripe tube 4 collects spectral information and fingerprint images of the plasma or the ash; after the combustion full experiment is finished, opening the exhaust gas recovery device 74 and the flange 77 of the exhaust gas recovery device 76 connected with the sample chamber, treating the exhaust gas, and closing the flange after the treatment is finished; when the spectrum detection is carried out on the ashes generated by combustion, the sample placing groove 72 is controlled to rotate anticlockwise by 30 degrees, so that the pulse laser can fully act with the sample ashes, and the time resolution spectrum information and the fingerprint image of the femtosecond level can be extracted.
In summary, the present invention provides a spectrum detection system with high time resolution and capable of automatically processing a polluted gas, aiming at the disadvantages of low time resolution, long measurement time, etc. of the current LIBS spectrum detection system based on PMT or ICCD, comprising: the system comprises a pulse laser, a transmitting optical system, a time delay system, a receiving optical system, an optical fiber image sensor, a grating beam splitter prism, a sample chamber, a rotary table, a stripe tube detector, an ICCD enhancer, an exhaust gas recovery device and a computer system. The streak tube detector adopts a streak tube with a large detection range and sub-femtosecond time resolution; the optical fiber image sensor is reasonably selected according to the effective detection range of the receiving optical system and the cathode of the strip tube detector; the exhaust gas recovery apparatus may be designed according to the pollutants. The invention has the advantages of high time resolution, high response speed, wide spectrum and no pollution.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (9)
1. LIBS spectrum detection system with waste gas recovery function based on inferior femtosecond stripe camera, its characterized in that:
the device comprises a femtosecond high-energy pulse laser (1), a beam splitter (2), a delay system (3), a sub-femtosecond stripe tube detector (4), a dielectric film reflector (5), a reflecting telescope (6), a sample chamber and waste gas recovery device (7), an optical focusing lens (8), an optical fiber (9), a grating beam splitter system (10), a cylindrical focusing lens (11), an ICCD (12) and a computer system (13);
the high-energy femtosecond pulse laser (1) is used for emitting high-energy femtosecond pulse laser with a required wavelength;
a beam splitter (2) for splitting the femtosecond high-energy pulse laser;
the delay system (3) is used for synchronously working the femtosecond high-energy pulse laser (1) and the streak tube detector (4) at the same time;
the stripe tube detector (4) is used for receiving the optical signal after passing through the grating beam-splitting prism (10) and converting the input high-speed time signal into a low-speed space signal to form a spectrum signal with high time resolution;
a dielectric film reflector (5) for reflecting the femtosecond high-energy pulse laser after passing through the beam splitter (2) to a reflective telescope (6);
a reflective telescope (6) for focusing the laser pulse signal reflected by the dielectric film reflector (5) to the sample chamber (7) and collecting the echo signal of the sample;
the outer parts of the sample chamber and the waste gas recovery device (7) are opposite to the reflecting telescope (6);
an optical focusing lens (8) for focusing the echo signal to an optical fiber (9);
an optical fiber (9) for emitting the focused optical signal to a grating beam-splitting prism (10);
a grating light splitting system (10) for spatially separating optical signals of different wavelengths;
the cylindrical focusing lens (11) is used for focusing the spectrum signal output by the grating light-splitting system (10) into a bit signal and transmitting the bit signal to the photocathode of the streak tube detector (4);
an ICCD (12) for amplifying the weak time-resolved spectroscopic signal;
and a computer (13) for processing and analyzing the spectral information.
2. The LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond stripe camera according to claim 1, wherein the femto-second high-energy pulse laser (1) is a high-power high-energy femto-second laser, the output pulse laser wavelength is 515nm/343nm/257nm/206nm, and the energy is 1 mJ-200 mJ level; the pulse width of 20 fs-50 fs is adjustable.
3. The LIBS spectrum detection system with the exhaust gas recovery function based on the sub-femtosecond streak camera according to claim 1, wherein the streak tube detector (4) is a sub-femtosecond time resolution large detection range streak tube, and comprises a photocathode (41), an acceleration system (42), a time focusing system (43), an anode system (44), a scanning deflection system (45), a spatial focusing system (46) and a fluorescent screen (47) which are sequentially arranged;
wherein, the photocathode (41) is used for converting the external optical image into an electronic image;
an acceleration system (42) for accelerating the electron image emitted by the photocathode (41);
a time focusing system (43) for focusing the electronic image in a time direction;
an anode system (44) for accelerating electrons, removing large angle electrons and collimating the electron image;
a scanning deflection system (45) for converting time information of the electronic image output from the anode system (44) into spatial information;
a spatial focusing system (46) for focusing the electronic image of the exit scanning deflection system (45) in a spatial direction;
a phosphor screen (47) for converting the electronic image after focusing by the spatial focusing system (46) into a visible optical image.
4. A LIBS spectrum detection system with exhaust gas recovery function based on a sub-femtosecond stripe camera according to claim 3 characterized in that the photocathode (41) is a planar photocathode;
the accelerating system (42) is a high-precision grid structure accelerating system and comprises a planar high-precision grid structure (421), and an electron diffusion preventing upper polar plate (422) and an electron diffusion preventing lower polar plate (423) which are arranged at the rear end part of the high-precision grid structure (421) along the space direction are arranged in parallel;
the time focusing system (43) is a flat-plate type focusing system and comprises two parallel plates which are symmetrically arranged, and the first parallel plate (431) and the second parallel plate (432) adopt cuboid structures;
the anode system (44) is of a flat plate structure, an electron inlet of the anode system is an upper polar plate (441) of a parallel plate structure and a lower polar plate (442) of a parallel plate structure, a first baffle structure (443) which is mutually perpendicular to the upper polar plate (441) of the parallel plate structure is arranged at an electron outlet, and a second baffle structure (444) which is mutually perpendicular to the lower polar plate (442) of the parallel plate structure is arranged at the electron outlet;
the width of the slit between the first baffle structure (443) and the second baffle structure (444) is adjustable;
the scanning deflection system (45) is a flat-plate type scanning deflection system and comprises an upper polar plate (451) and a lower polar plate (452) which are symmetrically arranged up and down, and an electron inlet of the scanning deflection system is close to a slit between the anode first baffle structure (443) and the anode second baffle structure (444);
the space focusing system (46) is a single lens focusing system and comprises a first focusing electrode upper polar plate (4611) and a first focusing electrode lower polar plate (4612), a second focusing electrode upper polar plate (4621) and a second focusing electrode lower polar plate (4622), a third focusing electrode upper polar plate (4631) and a third focusing electrode lower polar plate (4632) which are sequentially arranged along the electron propagation direction and have the same distance from an optical axis and the same axial length;
the first focusing electrode upper plate (4611) and the first focusing electrode lower plate (4612) are arranged in parallel, the second focusing electrode upper plate (4621) and the second focusing electrode lower plate (4622) are arranged in parallel, and the third focusing electrode upper plate (4631) and the third focusing electrode lower plate (4632) are arranged in parallel.
5. The LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond stripe camera according to claim 4, wherein the photocathode (41), the acceleration system (42), the time focusing system (43), the anode system (44), the scanning deflection system (45), the space focusing system (46) and the fluorescent screen (47) are sequentially connected through a ceramic ring or a glass ring;
the planar high-precision grid structure (421) of the acceleration system (42) is electrically connected with the upper electrode plate (422) and the lower electrode plate (423) for preventing electron diffusion;
an upper plate (441) of the parallel plate structure of the anode system (44) is electrically connected with a first baffle structure (443), and a lower plate (442) of the parallel plate structure is electrically connected with a second baffle structure (444);
the first focusing electrode upper polar plate (4611), the second focusing electrode upper polar plate (4621) and the third focusing electrode upper polar plate (4631) of the space focusing system (46) are sequentially connected through a ceramic ring or a glass ring, and the first focusing electrode lower polar plate (4612), the second focusing electrode lower polar plate (4622) and the third focusing electrode lower polar plate (4632) are sequentially connected through a ceramic ring or a glass ring.
6. The LIBS spectrum detection system with exhaust gas recovery function based on the sub-femtosecond streak camera according to claim 4, wherein the effective imaging range of the photocathode of the streak tube detector (4) is 4mm x 40 μm;
the space length of the one-dimensional optical signal after being focused by the cylindrical focusing lens (11) is smaller than 4mm, and the width is smaller than 4 mu m;
the distance between the upper polar plate (422) for preventing the electron diffusion of the accelerating system and the lower polar plate (423) for preventing the electron diffusion of the accelerating system is 9-13 mm; the length along the optical axis direction is 9 mm-13 mm;
the distance between the upper polar plate (441) of the front parallel plate structure and the lower polar plate (442) of the parallel plate structure of the anode system (44) is 2 mm-5 mm, the width is 30 mm-40 mm, and the length along the optical axis direction is 20 mm-28 mm; the rear end is provided with a first baffle structure (443) and a second baffle structure (444), and the interval between the first baffle structure (443) and the second baffle structure (444) is 5-50 mu m;
the first focusing electrode upper polar plate (4611) and the first focusing electrode lower polar plate (4612), the second focusing electrode upper polar plate (4621) and the second focusing electrode lower polar plate (4622) are respectively arranged at intervals of 10 mm-30 mm; the dimension along the length direction of the optical axis is 30 mm-40 mm; the thickness is 0.5mm;
the radius of the fluorescent screen (47) is 15-25 mm.
7. The LIBS spectrum detection system with the waste gas recovery function based on the sub-femtosecond stripe camera according to claim 4, wherein the potential difference between the photocathode (41) and the acceleration system (42) is 10 kV-16 kV;
the potential difference between the time focusing system (43) and the anode system (44) is 8 kV-13 kV;
the potential difference between the fluorescent screen (47) and the space focusing system (46) is 6 kV-11 kV;
the electric potential between the first focusing electrode upper polar plate (4611), the first focusing electrode lower polar plate (4612), the third focusing electrode upper polar plate (4631) and the third focusing electrode lower polar plate (4632) is 0V, and the electric potential difference between the first focusing electrode upper polar plate (4611) and the second focusing electrode upper polar plate (4621) is 3 kV-5 kV.
8. The lifs spectrum detection system with an exhaust gas recovery function based on a sub-femto-second streak camera of claim 1, wherein the sample chamber and exhaust gas recovery device (7) comprises: the device comprises a device body, a sample placing rotary table (78), a sample supporting rod (79), a sample (71), a sample placing groove (72), a flange (77), a first waste gas recovery device (74) and a second waste gas recovery device (76), an ignition source device (73) and a combustion improver containing device (75);
wherein the number of the flanges (77) is a plurality, and the flanges are arranged on the outer wall of the device body, one flange is used for being connected with the ignition source device (73), one flange is used for being connected with the combustion improver device (75), and one flange is used for placing a sample; two further flanges for connection to a first exhaust gas recovery means (74) and a second exhaust gas recovery means (76);
the device body is connected with a sample placing rotary table (78) through a sample supporting rod (79);
the sample placing turntable (78) can rotate 0-360 degrees along the horizontal direction;
the sample placing groove (72) can rotate anticlockwise by 0-45 degrees;
the sample placing groove (72) is a groove type sample holder and is used for placing a sample;
the sample support is provided with a hole with the size of the laser beam spot for spectrum detection.
9. The lifs spectrum detection system with exhaust gas recovery function based on the sub-femto-second streak camera of claim 8, wherein the ignition source placement device (73) and the combustion improver placement device (75) are separated from the sample chamber (7) by a flange (77) at the initial stage of the experiment, and are separated by the flange (77) before and after the experiment;
the first waste gas recovery device (74) and the second waste gas recovery device (76) are isolated from the sample chamber (7) through a flange (77) in the experimental stage;
when LIBS detection is needed for the burning ashes, the sample tray (72) is started to rotate anticlockwise for 30-45 degrees.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104034703A (en) * | 2014-06-12 | 2014-09-10 | 中国科学院上海技术物理研究所 | Improved system and method for detecting composition of material by LIBS (Laser Induced Breakdown Spectroscopy) with high signal and noise ratio and low detection limit |
| CN108152268A (en) * | 2018-01-08 | 2018-06-12 | 威海怡和专用设备制造有限公司 | LIBS spectrum investigating systems based on streak tube |
| CN112213297A (en) * | 2020-10-10 | 2021-01-12 | 中北大学南通智能光机电研究院 | Paraxial double-pulse LIBS system based on annular light beam |
| CN114544597A (en) * | 2022-03-24 | 2022-05-27 | 郭帅 | LIBS spectral line enhancement system based on double laser beams in different time domains |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104034703A (en) * | 2014-06-12 | 2014-09-10 | 中国科学院上海技术物理研究所 | Improved system and method for detecting composition of material by LIBS (Laser Induced Breakdown Spectroscopy) with high signal and noise ratio and low detection limit |
| CN108152268A (en) * | 2018-01-08 | 2018-06-12 | 威海怡和专用设备制造有限公司 | LIBS spectrum investigating systems based on streak tube |
| CN112213297A (en) * | 2020-10-10 | 2021-01-12 | 中北大学南通智能光机电研究院 | Paraxial double-pulse LIBS system based on annular light beam |
| CN114544597A (en) * | 2022-03-24 | 2022-05-27 | 郭帅 | LIBS spectral line enhancement system based on double laser beams in different time domains |
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