A quartz tuning fork type laser breakdown detection device

Abstract

A quartz tuning fork type laser breakdown detection device includes a photoacoustic absorption cavity, an excitation light source, a detection light source, a detection light modulation unit, and a quartz tuning fork detector. The quartz tuning fork detector is composed of a resonance tube and a quartz tuning fork. When working, the excitation light is focused and incident on the substance to be tested, and the substance to be tested forms a nanoparticle cloud due to heat absorption and diffuses into the photoacoustic absorption cavity, and the detection light is absorbed by the components in the nanoparticle cloud to generate photoacoustic Effect, the sound energy is accumulated in the resonance tube and transmitted to the quartz tuning fork to output an electrical signal, based on which the content of a certain component in the substance to be tested is estimated. The invention combines laser-induced breakdown and photoacoustic spectroscopy to improve the detection limit of the traditional laser-induced breakdown method; the quartz tuning fork is used as the detection device, which effectively simplifies the detection system; The broadening effect is small, the detected spectral lines are easy to distinguish and the noise is small, and the detection sensitivity is improved.

Description

technical field [0001] The invention relates to the technical field of spectrum measurement, in particular to a laser-induced breakdown detection device using quartz tuning fork photoacoustic spectroscopy, which is suitable for quantitative analysis of substance concentration. Background technique [0002] Laser-induced breakdown spectroscopy is a laser ablation spectral analysis method. The laser is focused on the substance to be measured (which can be solid, liquid or gas) through a lens. When the energy density of the laser is greater than the breakdown threshold of the substance to be measured, the first Nanoscale cloud clusters will be generated, and plasma will be generated if the laser continues to irradiate. The local energy density and temperature of this plasma are very high. Use a spectrometer to collect the signal of the emission line generated on the plasma surface of the substance to be measured, and then you can use the emission Quantitatively analyze the conc...

AI Technical Summary

Problems solved by technology

[0004] At present, the detection limit of the current laser-induced breakdown spectroscopy is on the order of ppm, and there is still a problem of low detection sensitivity.

However, when using photoacoustic spectroscopy to directly detect solid substances, the detection sensitivity decreases and the spectral lines are difficult to distinguish due to the problem of spectral line broadening.

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