A Method for Improving the Measurement Accuracy of Elements Based on Double Pulse and Spatial Confinement

Abstract

The invention discloses a method for improving element measurement accuracy based on double pulse and space confinement, which belongs to the technical field of atomic emission spectrometry. In this method, pits or cavities are first made on the surface of the sample to be tested, and then the sample is hit by a double-pulse laser. The first pulse creates a low-pressure environment inside the pit or chamber, and the second pulse excites the sample to create a plasma. The plasma is limited by space during the expansion process, which makes the plasma temperature and electron density significantly increased, and the plasma is more uniform, which is conducive to increasing the stability of the measurement signal, improving the signal-to-noise ratio, and reducing the detection of trace elements in the sample. limit. This method has the characteristics of good calibration and high prediction accuracy.

Description

technical field [0001] The invention relates to a method for improving element measurement accuracy based on double pulses and space limitation, and belongs to the technical field of atomic emission spectrometry. Background technique [0002] LIBS is a brand-new material element analysis technique developed in the late 20th century. The working principle of LIBS 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 frequency are radiated and characteristic spectral lines are generated. The frequency and intensity information of the sample contains the analysis object. The element type and concentration information. LIBS technology has the advantages of low operating cost, fast measurement speed, high sensitivity, no or little sample pretreatment and multi-element measurement, and no radiation hazard, so it has great development potential in industri...

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Problems solved by technology

[0003] However, because the laser action point of LIBS 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, the fluctuation of laser energy, the fluctuation of physical parameters such as plasma temperature and electron density Differences lead to low repeatability of LIBS 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 measurement accuracy of direct measurement samples using LIBS cannot be guaranteed, which limits the use of LIBS in Application in production

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