Online powder detecting device and measuring method based on laser-induced breakdown spectroscopy

Abstract

The invention discloses an online powder detecting device and an online powder measuring method based on laser-induced breakdown spectroscopy, and belongs to the technical field of atomic emission spectroscopy measurement. The device comprises a laser-induced breakdown system and a powder sampling system, wherein the powder sampling system comprises a powder jet pump, an air compressor, a sample chamber and a powder conveying pipeline arranged in the sample chamber. A powder sample is conveyed through the conveying pipeline made of an insulating material by utilizing air flow; laser light passes through a detection hole in the side wall of the conveying pipeline to break the powder sample down so as to form plasma; the plasma emits a spectral line signal, and the spectral line signal passes through a window lens of the sample chamber, is collected by a collection lens and optical fiber, is guided into a spectrometer and then is used for a spectral analysis; meanwhile, high voltage is exerted on an electrode embedded into the conveying pipeline to generate a strong electric field, and the strong electric field is used for enhancing the signal emitted by the plasma. According to the device, the signal emitted by the plasma is enhanced through a discharge effect, and the measurement stability is improved, and the pollution of an optical device caused by flying of powder out of the conveying pipeline can be prevented.

Description

technical field [0001] The invention relates to an online powder detection device and measurement method based on laser-induced breakdown spectroscopy technology, belonging to the field of atomic emission spectroscopy measurement. Background technique [0002] Laser-induced breakdown spectroscopy (LIBS for short), also known as laser-induced plasma spectroscopy, is a brand-new material element analysis technology developed in the late 20th century. The working principle of laser-induced breakdown spectroscopy technology is: under the action of strong laser pulses, the material on the surface of the sample is excited to become plasma and decays rapidly. During the decay process, photons of specific frequencies are radiated to generate characteristic spectral lines. The information includes the element type and concentration information of the analysis object. Laser-induced breakdown spectroscopy has the advantages of low operating cost, fast measurement speed, high sensitivi...

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Problems solved by technology

[0003] However, since the laser action point of laser-induced breakdown spectroscopy technology is very small, the amount of ablated material is very small, and the matrix effect is very obvious for inhomogeneous and anisotropic materials; at the same time, fluctuations in laser energy, plasma temperature, electron The difference in physical parameters such as density leads to low repeatability of laser-induced breakdown spectroscopy measurement; in addition, the influence of environmental parameters and the electronic noise of the internal components of the instrument are likely to interfere with LIBS; therefore, the use of laser-induced breakdown spectroscopy The measurement accuracy of the technology directly measuring the sample cannot be guaranteed, which limits the application of laser-induced breakdown spectroscopy technology in actual production

[0004] The LIBS device used for on-line detection of solid powder samples usually has the phenomenon of powder scattering, which leads to increased detection uncertainty

Powder flying will also contaminate the optical components in the LIBS device, which directly leads to the weakening of laser energy and measurement signal

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