Laser-Induced Breakdown Spectroscopy Precision via Sample Pressing and Aerosol Layer
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Solution Overview
Problem
Laser-induced breakdown spectroscopy (LIBS) faces challenges in precision due to the matrix effect, inhomogeneity, anisotropy, variability in laser energy, and environmental interference, limiting its accuracy and repeatability for industrial applications.
Innovation Solution
A method and system that involve press-forming samples into a round pie with a smooth surface, creating a cavity, and forming a uniform aerosol layer above the sample using submicron granules mixed with a protective gas, combined with a laser-induced breakdown spectroscopic system that splits and focuses laser beams at adjustable angles to generate plasma with increased electron density and temperature, improving spectral line intensities and signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct measurement is performed using LIBS, then measurement speed is fast and operating cost is low, but measurement precision is poor due to matrix effect and inhomogeneity
Solution Approach 1:
The sample is press-formed into a tablet with a smooth surface before measurement. This preliminary action ensures uniform distribution of elements and eliminates matrix effects that would otherwise degrade measurement precision, while maintaining the fast measurement capability of LIBS.
2Measurement precision
If simple preprocessing is applied to improve measurement accuracy, then measurement precision improves slightly, but uncertainty and interference from environmental parameters and electrical noise remain
Solution Approach 1:
The sample is press-formed into a tablet with a smooth surface before measurement. This preliminary action ensures uniform distribution of elements and eliminates matrix effects that would otherwise degrade measurement precision, while maintaining the fast measurement capability of LIBS.
Solution Approach 2:
The physical state of the sample is changed from loose powder to a compacted tablet with controlled density and surface smoothness. This parameter change ensures homogeneous element distribution and eliminates matrix effects, thereby improving both precision and repeatability of measurements.
3Measurement precision
If laser focuses at a small point to achieve high sensitivity, then detection capability improves, but matrix effect and anisotropy become more significant
Solution Approach 1:
The sample is press-formed into a tablet with a smooth surface before measurement. This preliminary action ensures uniform distribution of elements and eliminates matrix effects that would otherwise degrade measurement precision, while maintaining the fast measurement capability of LIBS.
Solution Approach 2:
The sample is press-formed into a tablet with a smooth surface to achieve homogeneous element distribution. This homogeneity ensures that the laser interaction is uniform across the measurement point, eliminating matrix effects and anisotropy while maintaining high detection sensitivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the reproducibility and precision of element measurement by reducing uncertainty, increasing the detection limit of microelements, and improving the goodness of fit of calibration curves, while also lowering the energy threshold for plasma formation and enhancing ablation efficiency.
Implementation Method 1
under the effect of a strong laser pulse, within a region of the surface of a sample on which the laser focuses, atoms, molecules and the like, which constitute the sample substance, are actuated into plasma after a series of processes including multiphoton ionization, absorption of photons
Implementation Method 2
the actuated plasma decays rapidly after the strong laser pulse is stopped, during which photons with specific frequencies are radiated thereby generating characteristic spectral lines
Implementation Method 3
forming a layer of aerosol immediately above the surface of the sample to be measured with the components thereof completely identical to those of the sample to be measured
Implementation Method 4
splitting the laser beam emitted from the laser into two beams by a spectroscope; reflecting the beams with mirrors so as to enable the angles between the incidence directions of the two laser beams split by the spectroscope and the normal direction of the surface0 of the sample to be measured to be in the range of 0°∼90°
Data Source
Figure 1~2
Figure 3~4
Figure 5(A)~6(B)
AI summary
The present invention provides a method and a system for improving the precision of element measurement based on laser-induced breakdown spectroscopy. The method comprises: press-forming a sample to be measured with a tablet press; making a cavity on or immediately above a surface of the press formed sample; forming a layer of aerosol immediately above the surface of the sample to be measured with the components thereof completely identical to those of the sample to be measured; testing the sample to be measured by using a laser-induced breakdown spectroscopic system, so as to obtain the intensities of the characteristic spectral lines of a target element in the sample to be measured; and determining the concentration of the target element in the sample to be measured according to a calibration curve of the target element in prearranged calibration samples. With the present invention, the plasma formed by laser ablation can be more uniform and more in conformity with the condition of Local Thermodynamic Equilibrium, thereby increasing the reproducibility of the measurement and improving the precision of element measurement in laser-induced breakdown spectroscopy technology.