Remote Laser-induced Breakdown Spectroscopy Research Articles

Detection of Al, Mg, Ca, and Zn in copper slag by LIBS combined with calibration curve and PLSR methods

The precise measurement of Al, Mg, Ca, and Zn composition in copper slag is crucial for effective process control of copper pyrometallurgy. In this study, a remote laser-induced breakdown spectroscopy (LIBS) system was utilized for the spectral analysis of copper slag samples at a distance of 2.5 m. The composition of copper slag was then analyzed using both the calibration curve (CC) method and the partial least squares regression (PLSR) analysis method based on the characteristic spectral intensity ratio. The performance of the two analysis methods was gauged through the determination coefficient (R 2), average relative error (ARE), root mean square error of calibration (RMSEC), and root mean square error of prediction (RMSEP). The results demonstrate that the PLSR method significantly improved both R 2 for the calibration and test sets while reducing ARE, RMSEC, and RMSEP by 50% compared to the CC method. The results suggest that the combination of LIBS and PLSR is a viable approach for effectively detecting the elemental concentration in copper slag and holds potential for online detection of the elemental composition of high-temperature molten copper slag.

Effects of feature engineering on the robustness of laser-induced breakdown spectroscopy for industrial steel classification

Steel is a widely used material. Since steel has different properties and uses depending on the steel type, it is essential to accurately classify the steel types. LIBS is a promising technique for real-time classification due to its advantages such as rapid analysis and feasibility of measurement in air. However, enhancing the robustness of classification models is still challenging in industrial applications. This study investigates the effects of feature engineering on the robustness of laser-induced breakdown spectroscopy (LIBS) for industrial steel classification. To make LIBS applicable to the steel industry, a remote LIBS system was developed. The LIBS system was utilized to classify the six representative types of steel. To evaluate the performance of the LIBS system, the measurements were reproduced, with the same sample, at seven different laser energies. The robustness of the LIBS system was investigated by conducting experiments using various feature-engineering and learning-based algorithms on the LIBS data, with test datasets having laser energies different from those of the training datasets. The results indicate that the LIBS signal intensity ratio as the input data leads to a more robust classification model than using principal components or random forest-based datasets. In addition, the intensity ratios with similar upper-state energies were found to be more suitable input data for steel classification. These findings demonstrate the potential of the LIBS system for the highly accurate and robust classification of industrial-grade steel.

Development of a radiation tolerant laser-induced breakdown spectroscopy system using a single crystal micro-chip laser for remote elemental analysis

ABSTRACT For the development of the remote elemental analysis method in a radiation environment based on the laser-induced breakdown spectroscopy (LIBS), the radiation effects on the laser oscillation properties of the single crystal (SC) Nd:YAG microchip laser (MCL) were investigated and compared with those of ceramic Nd:YAG MCL. The laser oscillation properties were measured under gamma ray irradiation as a function of dose rate. The effects on the SC MCL properties were very small compared to those on the ceramics, indicating minimal radiation effects on the LIBS signal when using SC MCL. Pulse energy and oscillating build-up time (BUT) were measured for cumulative dose exceeding 1400 kGy. The pulse energy remained stable under irradiation. The BUT also remained stable, demonstrating negligible optical loss accumulation that could affect laser properties even at the demonstrated cumulative dose. The results indicate that the effects of dose rate and cumulative dose on SC MCL laser properties are minimal. The SC MCL was then integrated into the LIBS system, and the gadolinium signal was successfully measured at a dose rate of 5 kGy/hr. These findings highlight the radiation tolerance of SC MCL for remote LIBS applications in harsh radiation environments.

Remote Laser-Induced Breakdown Spectroscopy of Bacterial Growths in Carbonate Rocks in a Mars-like Atmosphere.

Understanding the past habitable environments of Mars increases the requirement to recognize and examine modern analogs and to evaluate the mechanisms that may preserve biosignatures in them. The phenomenon that originates and preserves possible microbial biosignatures in mineral phases is of particular interest in astrobiology. On Earth, the precipitation of carbonate matrices can be mediated by bacteria. Besides microbialites and other sedimentary structures, carbonate formations can be observed in certain karstic caves. The present work is focused on the remote laser-induced breakdown spectroscopy (LIBS) characterization of cyanobacteria, exploring the possibilities for identification and discrimination on carbonate substrates. For this purpose, the extremophile cyanobacterium Chroococcidiopsis sp. (collected from the Nerja Cave, Malaga, Spain) was analyzed under laboratory-simulated martian conditions in terms of chemical composition and gas pressure. LIBS results related to acquired molecular emission features allowed bacterial differentiation from the colonized mineral substrate. In addition, the limits of detection were estimated with a laboratory-grown culture of the cyanobacterium Microcystis aureginosa. Our results reveal LIBS's capability to detect biological traces under simulated martian conditions. Additionally, the time-resolved analysis of the biological samples demonstrates the selection of optimal temporal conditions as a critical parameter for the preferential acquisition of molecular species in organic material.

LIBS-MLIF Method: Stromatolite Phosphorite Determination

The search for biominerals is one of the core targets in the deep space exploration mission. Stromatolite phosphorite is a typical biomineral that preserves early life on Earth. The enrichment of phosphate is closely related to microorganisms and their secretions. Laser-induced breakdown spectroscopy (LIBS) has become an essential payload in deep space exploration with the ability to analyze chemical elements remotely, rapidly, and in situ. This paper aims to evaluate the rapid identification of biological and non-biological minerals through a remote LIBS payload. LIBS is used for element analysis and mineral classification determination, and molecular laser-induced fluorescence (MLIF) is used to detect halogenated element F to support the existence of fluorapatite. This paper analyzes the LIBS-MLIF spectral characteristics of stromatolites and preliminarily evaluates the feasibility of P element quantification. The results show that LIBS technology can recognize biological and non-biological signals. This discovery is significant because it is not limited to detecting and analyzing element composition. It can also realize the detection of molecular spectrum based on selective extraction of CaF molecule. Therefore, the LIBS payload still has the potential to search for biomineral under the condition of adjusting the detection strategy.

Initial Drift Correction and Spectral Calibration of MarSCoDe Laser-Induced Breakdown Spectroscopy on the Zhurong Rover

The Mars Surface Composition Detector (MarSCoDe) carried by the Zhurong rover of China’s Tianwen-1 mission uses Laser-Induced Breakdown Spectroscopy (LIBS) to detect and analyze the material composition on Martian surfaces. As one extraterrestrial remote LIBS system, it is necessary to adopt effective and reliable preprocessing methods to correct the spectral drift caused by the changes in environmental conditions, to ensure the analysis accuracy of LIBS scientific data. This paper focuses on the initial spectral drift correction and estimates the accuracy of on-board wavelength calibration on the LIBS calibration target measured by the MarSCoDe LIBS. There may be two cases during the instrument launch and landing, as well as the long-term operation: (a) the initial wavelength calibration relationship can still apply to the on-board LIBS measurement; and (b) the initial wavelength calibration relationship has been changed, and a new on-board calibration is needed to establish the current relationship. An approach of matching based on global iterative registration (MGR) is presented in respect to case (a). It is also compared with the approach of particle swarm optimization (PSO) for case (b). Furthermore, their accuracy is estimated with the comparison to the National Institute of Standards and Technology (NIST) database. The experimental results show that the proposed approach can effectively correct the drift of the on-board LIBS spectrum. The the root-mean-square error (RMSE) of the internal accord accuracy for three channels is 0.292, 0.223 and 0.247 pixels, respectively, compared with the corrected Ti-alloy spectrum and the NIST database, and the RMSE of the external accord accuracy is 0.232, 0.316 and 0.229 pixels, respectively, for other samples. The overall correction accuracy of the three channels is better than one-third of the sampling interval.

Influence of Standoff Distance and Sunlight on Detection of Pollution Deposits on Silicone Rubber Insulators Adopting Remote LIBS Analysis

Silicone rubber (SR) insulators have been coated with different concentrations of NaCl to study the contamination level adopting laser-induced breakdown spectroscopy (LIBS) analysis. An elemental study of LIBS spectral data has identified the sodium peaks, thereby indicating the presence of salt deposits. A regression coefficient is used for a better understanding of the direct correlation between the salt deposit density (SDD) and the normalized intensity ratio, at various standoff distances. A marginal decrement in the normalized intensity ratio of the sodium peaks has been noticed in the case of readings taken at morning and midday, compared to those taken at night at different SDD values and different energies of the laser pulse. With increase in SDD, the intensity distribution characteristics have a right shift on the intensity scale. The polluted SR specimens are successfully classified by employing artificial neural network technique. Overall, the LIBS method is successful in identifying the variations in the salt deposition on the surface of the insulator, even at far distances of 15 m and at any time of the day.

Ground calibration and validation of laser-induced breakdown spectroscopy for the Mars surface composition detector

<p indent=0mm>In the Tianwen-1 mission, China’s first Mars exploration, the lander/rover had safely landed in the south Utopian plain and conducted a series of scientific explorations. The Mars surface composition detector (MarSCoDe) equipped on the Zhurong rover uses remote laser-induced breakdown spectroscopy (LIBS) and short-wave infrared spectroscopy to perform the <italic>in situ</italic> detection of the elemental composition of surface soils, rocks, and minerals on Mars. In this paper, first, the basic components of this instrument suite are introduced. Second, the LIBS principle is described. Third, the spectral and radiation calibration of the LIBS spectrometer and its surveying distance and pointing angle calibration are described. Finally, the performance associated with the navigation and terrain cameras (NaTeCam) is presented. The results from the joint detection and analysis of the MarSCoDe and the NaTeCam show that the MarSCoDe can accurately fire the target and determine the elemental components.

Development of Remote Laser-Induced Breakdown Spectroscopy Technique for Salt Damage Assessment in Concrete Structures

Development of Remote Laser-Induced Breakdown Spectroscopy Technique for Salt Damage Assessment in Concrete Structures

Improving ChemCam LIBS long-distance elemental compositions using empirical abundance trends

The ChemCam instrument on the Curiosity rover provides chemical compositions of Martian rocks and soils using remote laser-induced breakdown spectroscopy (LIBS). The elemental calibration is stable as a function of distance for Ti, Fe, Mg, and Ca. The calibration shows small, systematically increasing abundance trends as a function of distance for Al, Na, K, and to some extent, Si. The distance effect is known to be due to a dependence with distance on the relative strengths of atomic transition lines. Emission lines representing transitions from relatively low energy levels remain intense at longer distances while emission lines representing transitions from higher energy levels decrease in intensity more rapidly as a function of distance. The multivariate algorithms used to determine elemental compositions rely on a large number of emission lines in many cases, so rather than trying to correct all emission lines, a study was made of the predicted compositions as a function of distance, in order to determine an empirical correction. Abundance trends can be well approximated by a linear trend with distance within the ranges of abundances and distances observed up to ~6 m. Data from 11 distinct geological members and data groups of the Murray formation in Gale crater, Mars, were used to form the model, selecting the members and data groups yielding the best statistics. The model was tested using data from several targets observed from two different distances, and using data from the Kimberley formation, the composition of which is significantly different from the Murray formation, showing that the model works on other compositions beyond those used to build the model. For long-distance observations up to ~6 m, corrections can be made back to an equivalent composition at the median distance of ChemCam observations (2.6 m). The model has been validated up to 6.2 m, although ChemCam is able to observe bedrock targets to >7 m, and iron meteorites to distances of >9 m.

Depth profiling of surface degradation of silicone rubber composite insulators by remote laser-induced breakdown spectroscopy

High-voltage silicone rubber composite insulators are widely used for outdoor insulation in power transmission lines. Silicone rubber, which is used as a housing material, gradually degrades with long-term use in the field. Therefore, to accurately determine the lifetime of composite insulators, it is essential to evaluate this degradation. This paper describes the results of depth profiling, which shows the change in the chemical composition caused by degradation, using laser-induced breakdown spectroscopy (LIBS). A remote LIBS system was constructed for application in in-situ degradation diagnostics. Field-aged insulators were irradiated with second harmonic Nd:YAG laser pulses at a distance of 10. The emission from the plasma was received by a telescope, and a spectroscopic analysis was performed. Energy dispersive X-ray spectroscopy (EDX) was performed for a comparative study. The emission intensity ratio of silicone to aluminum, which forms an alumina trihydrate filler, decreased by approximately 30% at the degraded surface compared to the undegraded bulk. A reduction in silicones at the degraded surface up to a depth of 300 was confirmed by LIBS and EDX measurements. These results show that remote LIBS using the ratio of silicone to aluminum as an index is a promising method for the in-situ diagnostics of composite insulators.

Remote identification and ranking of Sodium in bulk liquid under high pressure condition

Laser Induced Breakdown Spectroscopy (LIBS) based spectral and temporal measurements are carried out to identify and rank the Sodium in bulk liquid under high pressure condition. The experiments are carried out by varying the incident laser irradiance (4 to 5 * 1011 W/cm2), ambient pressure condition (1 to 8 atm) and stand-off collection distance (0.6 to 2 m). The concentration of Sodium Chloride (NaCl) in the sample solution is varied between 250 and 1500 ppm. From the spectral data, the Na I emission line (589 nm) is visualized for all experimentation condition. Emission due to singly ionized atom and doubly ionized atom are not observed, due to the requirement of high ionization energies. It is observed that the Na I (589 nm) peak intensity decreases with increase in ambient pressure condition, due to the plasma condensation effect. It is also observed that the Na I (589 nm) peak intensity increases with increase in incident laser irradiance. Temporal measurement based quantification of Sodium in bulk liquid is carried out. It is observed that the plasma emission time period (Na I at 589 nm) increases with increase in NaCl concentration. This is related to the re-excitation of neutral atoms (Na I) in the plasma state. In the stand-off distance analysis, it is observed that the plasma (Na I) emission peak intensity and time period of emission decreases with increase in stand-off collection distance. This might be due to the low coupling of plasma emission to the measurement system, at longer stand-off distances. The Na detection limit of about 10 ppm is achieved for a laser irradiance of 3 * 1011 W/cm2. The above specified detection limit is obtained for an ambient pressure condition of 1 atm and stand-off collection distance of 0.6 m. On a summary, remote LIBS with temporal measurement is highly suitable to identify and rank the Sodium concentration in bulk liquid under high pressure condition. However, the calibration of LIBS measurements at different experimental condition is required to utilize the instrument in real-time environment.

Discrimination of Aviation Alloy by Remote Laser-induced Breakdown Spectroscopy Technology

Discrimination of Aviation Alloy by Remote Laser-induced Breakdown Spectroscopy Technology

Assessing the type and quality of high voltage composite outdoor insulators by remote laser-induced breakdown spectroscopy analysis: A feasibility study

The use of composite polymeric insulators in overhead high voltage (HV) power transmission lines and in substations has been rapidly growing, as a result of their excellent operational performance, even under environmental pollution conditions. However, it has been observed that the insulation capacity of the composites deteriorates gradually for in-service insulators as a result of ageing, caused by several processes arising because of environmental, electrical and mechanical stresses. For these reasons, development of non-destructive diagnostic techniques for real-time, on-site inspection of the insulators' condition is required for ensuring high reliability of power transmission networks. To this end, laser-induced breakdown spectroscopy (LIBS) is found to offer an effective and reliable method for assessing the state of polymeric insulators, primarily silicone rubber (SIR) ones, that have been in service for up to 20 years on the HV power network of Crete, Greece. Determining the type of composite and furthermore the chemical integrity of the insulator is based on simple spectral indicators, which reflect the extent of chemical modifications induced on the insulator surface, as found in both standard and remote LIBS measurements performed in the laboratory. As a result, a stepwise diagnostic procedure was proposed and tested in an outdoors campaign, demonstrating that LIBS can become a field deployable technique for the efficient and reliable assessment of the performance of HV outdoor insulators in service.

Feasibility Investigation for Online Elemental Monitoring of Iron and Steel Manufacturing Processes using Laser-Induced Breakdown Spectroscopy

The metallurgical industries are very important for social development. In order to improve the metallurgical techniques and quality of products, the real-time analysis and monitoring of iron and steel manufacturing processes are very significant. Laser-induced breakdown spectroscopy (LIBS) has been studied and applied for the contents measurement of iron and steel. In this paper, the remote open-path LIBS measurement was studied under different sample temperature, lens to target distance (LTD), sample angle conditions to clarify its online measurement features. The 3D profile measurement system of parallel laser beam fringes projection was also developed to measure the sample profile at different sample temperature. The measurement results demonstrated the robustness of remote open-path LIBS system and 3D profile measurement system. However, the correction is necessary to enhance the detection ability of LIBS online measurement. In order to improve the precision and accuracy of real-time elemental measurement, an innovative co-axial laser beam measurement system combining LIBS and 3D profile techniques is proposed to automatically adjust the focus unit and measure the sample components. The further study of this promising method will be developed for online application of iron and steel manufacturing processes.

A compact Fourier transform spectrometer with no moving parts for laser induced breakdown spectroscopy

We report the development of a portable single-shot Fourier transform spectrometer for application in laser induced breakdown spectroscopy (LIBS) with a particular emphasis on remote or standoff LIBS. The device, based on a design by Harvey and Padgett[1], has a number of inherent features that give it performance advantages over a portable grating spectrometer, in particular a gain in signal to noise ratio (SNR). Tests with low-pressure discharge lamps show a gain in SNR of at least five times that of a traditional portable grating spectrometer in stand-off mode. In addition, the instrument has also demonstrated the ability to measure the spectrum from a short or ultrashort pulsed source in a single shot, e.g. a laser produced plasma.

A Two Components Approach for Long Range Remote Raman and Laser-Induced Breakdown (LIBS) Spectroscopy Using Low Laser Pulse Energy.

The remote detection of chemicals using remote Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS) is highly desirable for homeland security and NASA planetary exploration programs. We recently demonstrated Raman spectra with high signal-to-noise ratio of various materials from a 430 m distance during daylight with detection times of 1-10 s, utilizing a 203 mm diameter telescopic remote Raman system and 100 mJ/pulse laser energy at 532 nm for excitation. In this research effort, we describe a simple two-components approach that helps to obtain remote Raman and LIBS spectra of targets at distance of 246 m with 3 mJ/pulse in daytime. The two components of the method are: (1) a small spectroscopy system utilizing 76 mm diameter collection optics; and (2) a small remote lens near the target. Remote Raman spectra of various chemicals are presented here with detection time of 1 s. Remote LIBS spectra of minerals using single laser pulse of 3 mJ/pulse energy from a distance of 246 m are also presented. This research work demonstrates a simple approach that significantly improves remote Raman and LIBS capabilities for long range chemical detection with compact low laser power Raman and LIBS systems.

远程激光诱导击穿光谱定量分析铝合金中的微量元素

远程激光诱导击穿光谱定量分析铝合金中的微量元素

Mobile lidar system for environmental monitoring

A versatile mobile remote sensing system for multidisciplinary environmental monitoring tasks on the Chinese scene is described. The system includes a 20 Hz Nd:YAG laser-pumped dye laser, optical transmitting/receiving systems with a 30 cm and a 40 cm Newtonian telescope, and electronics, all integrated in a laboratory, installed on a Jiefang truck. Results from field experiments on atomic mercury DIAL mapping and remote laser-induced fluorescence and break-down spectroscopy are given.

Transition of Femtosecond-Filament-Solid Interactions from Single to Multiple Filament Regime

High-peak-power fs-laser filaments offer unique characteristics attractive to remote sensing via techniques such as remote laser-induced breakdown spectroscopy (R-LIBS). The dynamics of several ablation mechanisms following the interaction between a filament and a solid determines the emission strength and reproducibility of target plasma, which is of relevance for R-LIBS applications. We investigate the space- and time-resolved dynamics of ionic and atomic emission from copper as well as the surrounding atmosphere in order to understand limitations of fs-filament-ablation for standoff energy delivery. Furthermore, we probe the shock front produced from filament-target interaction using time-resolved shadowgraphy and infer laser-material coupling efficiencies for both single and multiple filament regimes through analysis of shock expansion with the Sedov model for point detonation. The results provide insight into plasma structure for the range of peak powers up to 30 times the critical power for filamentation Pcr. Despite the stochastic nucleation of multiple filaments at peak-powers greater than 16 Pcr, emission of ionic and neutral species increases with pump beam intensity, and short-lived nitrogen emission originating from the ambient is consistently observed. Ultimately, results suggest favorable scaling of emission intensity from target species on the laser pump energy, furthering the prospects for use of filament-solid interactions for remote sensing.