Raman spectrum multi-site excitation structure and gas analysis method

Abstract

The invention discloses a Raman spectrum multi-site excitation structure and a gas analysis method. The excitation structure comprises a plane mirror I, a plane mirror II and convex lenses arranged between the plane mirror I and the plane mirror II, the plane mirror I and the plane mirror II are arranged in parallel, and excitation cavities are formed between the convex lenses and the adjacent plane mirrors (and between adjacent convex lenses). According to the gas analysis method, to-be-detected samples at all sites are placed in the corresponding excitation cavities respectively, and the excitation laser acts on the to-be-detected samples in all the excitation cavities for multiple times at the same time such that gas molecule Raman signals are enhanced efficiently by increasing the acting distance between the laser and gas molecules. According to the invention, the laser acts on each to-be-detected gas sample in the plurality of excitation cavities for multiple times at the same time such that the defects of poor stability, complex structure and high cost of a traditional excitation structure are overcome, and meanwhile, the Raman spectrum multi-site excitation structure has theadvantages of long acting distance between the laser and the gas molecules, lower detection limit and high excitation efficiency.

Description

technical field [0001] The invention belongs to the technical field of Raman spectroscopy, and in particular relates to a Raman spectroscopy multi-site excitation structure and a gas analysis method. Background technique [0002] Hydrogen isotopes protium (H), deuterium (D), and tritium (T) combine with each other to form homonuclear hydrogen H2, D2, T2 and heteronuclear hydrogen HD, HT, DT. The analysis of hydrogen isotopes by Raman spectroscopy has the advantages of simple operation, non-destructive and online measurement. The composition ratio of hydrogen isotopes can be obtained by accurately measuring the intensity of its rotational (S branch) or vibrational (Q branch) peaks. Since the rotational peak intensity is related to the balance of positive and parahydrogen, and is greatly affected by the background, the hydrogen isotope Raman vibration peak is More for component analysis. However, due to the low density of gas molecules and the small Raman scattering cross se...

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Problems solved by technology

The traditional gas Raman spectroscopy enhancement technology uses a double-concave mirror structure, which has poor stability and difficult debugging, and is difficult to apply in actual industrial scenarios

The patent (ZL201910998074.1) discloses a Raman spectroscopy excitation structure and gas analysis method. The excitation structure uses a concave mirror and multiple plane mirrors to form a reflection cavity, and the excitation laser acts on the reflection cavity multiple times. The gas sample increases the distance between the laser and the gas molecules, thereby improving the Raman signal of the hydrogen isotope gas molecules. However, the excitation structure has only one reflective cavity, and the number and size of the reflective cavity are limited due to the influence of the laser focusing performance. , this structure is only suitable for Raman signal excitation on a single point sample, and it still has the defect of insufficient efficiency. However, in order to meet the needs of multi-site excitation analysis in the industry, if the above excitation structure is used, multiple corresponding lasers must be equipped at the same time And spectrum analyzer, which greatly increases the cost, and the total volume of the equipment is too large

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