Laser-induced Breakdown Spectroscopy Research Articles

Rapid detection and discrimination of plant leaves using laser-induced breakdown spectroscopy

Rapid detection and discrimination of plant leaves using laser-induced breakdown spectroscopy

Effects of laser ablation of olivine on chamber optical window transmission loss and its recovery

Optical windows play a crucial role in laser ablation systems by protecting delicate components inside the chamber while allowing the transmission of laser energy. However, material buildup during the laser ablation process can lead to a significant loss of optical transmission over time. In this work, material deposition on the optical window by laser ablation of olivine using two laser systems operating at 30 kHz, 1 mJ pulse energy, and 20 Hz, 9.6 mJ pulse energy was performed and its impact on the window’s transmission properties, laser-induced breakdown spectroscopy (LIBS) signal, and window recovery is presented. Ablation at 30 kHz with 1 mJ pulses for 10 min resulted in substantial particle deposition on the window, causing a significant drop in transmission. Transmission of clean window dropped abruptly from 90% to nearly 0% (in the UV region from 200 to 300 nm) and 35% (at 600 nm) affecting the LIBS signal. In contrast, ablation at 20 Hz with 9.6 mJ pulses for 5 min showed no material deposition or transmission loss. Additionally, the study demonstrated that the same laser system used for ablation could be employed to remove the deposited material from the window, facilitating its recovery. Laser cleaning of the window at 30 kHz and 12 W average power restored the transmission values from 39% to 62% at 400 nm in the UV region, with potential for further improvement through parameter optimization. In addition, the identification of the hydroxyl group in olivine, which is relevant to NASA’s terahertz heterodyne spectrometer for in situ resource utilization project for the validation of water molecules is presented.

Aged Transformer Oil Analysis Through Laser-Induced Breakdown Spectroscopy

Aged Transformer Oil Analysis Through Laser-Induced Breakdown Spectroscopy

Detection of defects in composite insulators based on laser‐induced plasma combined with machine learning

AbstractDue to Prolonged operation and external environmental factors, composite insulators may develop various defects, which can potentially lead to serious accidents in power systems. Detecting and analyzing these defects is critically important. In this study, we combine machine learning with laser‐induced breakdown spectroscopy (LIBS) to identify defects in composite insulators and obtain spectral data from both defective and nondefective samples. The Uniform Manifold Approximation and Projection algorithm was employed to reduce the dimensionality of the data, thereby enhancing detection accuracy and efficiency. Decision tree, random forest (RF), K‐nearest neighbor, and support vector machine algorithms were used to classify the dimensionality‐reduced data. The results indicate that the RF algorithm achieved the best classification performance, with accuracies of 100% and 95.46% for the training and test sets, respectively. Furthermore, the precision, recall, and F1 scores, which reflect model performance, also showed superior results with the RF algorithm. These findings suggest that the combination of LIBS technology and machine learning can rapidly and accurately detect and analyze defects in composite insulators, offering new insights and methods for defect detection in composite insulators.

Design and optimization of handheld alloy analysis instrument based on microjoule high pulse repetition frequency LIBS.

We briefly describe the design of a handheld metal detection instrument based on microjoule high repetition frequency laser-induced breakdown spectroscopy. The instrument uses a Raspberry Pi as the control core and a laser with a frequency of 10kHz and a single pulse energy of 100 µJ as the excitation source. In addition, a mini-putter is built into the instrument to move the laser, allowing the ablation of the sample surface line area without external auxiliary equipment. The excitation-generated plasma radiation is collected by a simple optical path and transmitted directly to the spectrometer. We also constructed and trained a Backpropagation Artificial Neural Network (BP-ANN) model based on 12 different grades of alloys and transplanted the feedback process of the BP-ANN to the Raspberry Pi, which realized the rapid classification of the 12 alloys with >95% classification accuracy on the handheld instrument.

The role of modern spectroscopy and chromatography in actinide and lanthanide chemistry for nuclear forensics

The field of nuclear forensics relies heavily on the accurate identification and characterization of actinides and lanthanides to trace the origins and history of nuclear materials. Modern spectroscopy and chromatography play a pivotal role in this domain, offering precise analytical techniques to detect and quantify these elements in various samples. This review provides a comprehensive examination of the contributions of spectroscopy and chromatography to actinide and lanthanide chemistry within the context of nuclear forensics. It begins with an overview of the fundamental principles of these methods, followed by detailed discussions on the specific spectroscopic techniques such as mass spectrometry (including ICP-MS and TIMS), X-ray absorption spectroscopy (XANES and EXAFS), and laser-induced breakdown spectroscopy (LIBS). The chromatographic methods covered include high-performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE). The integration of these techniques for enhanced forensic analysis is explored through case studies and examples demonstrating their combined use. Furthermore, recent advances, innovations, and future trends in the field are discussed, highlighting the move towards automation and high-throughput analysis. The review concludes with an exploration of the analytical challenges and limitations, along with recommendations for future research directions. This comprehensive review underscores the critical role of advanced spectroscopy and chromatography in advancing the capabilities of nuclear forensics, ensuring robust and reliable forensic investigations.

Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laser-induced breakdown spectroscopy method

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve (SC) and calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technology to achieve synchronous, rapid, and accurate measurement of elements in a large number of samples, namely, SC-assisted CF-LIBS. Al alloy standard samples, divided into calibration and test samples, were applied to validate the proposed method. SC was built based on the characteristic line of Pb and Cr in the calibration sample, and the contents of Pb and Cr in the test sample were calculated with relative errors of 6% and 4%, respectively. SC built using Cr with multiple characteristic lines yielded better calculation results. The relative contents of ten elements in the test sample were calculated using CF-LIBS. Subsequently, the SC-assisted CF-LIBS was executed, with the majority of the calculation relative errors falling within the range of 2%–5%. Finally, the Al and Na contents of the Al alloy were predicted. The results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested samples. Furthermore, this quantitative analysis method was successfully applied to soil and Astragalus samples, realizing an accurate calculation of the contents of multiple elements. Thus, it is important to advance the LIBS quantitative analysis and its related applications.

Investigating critical metals Ge and Ga in complex sulphide mineral assemblages using LIBS mapping

Elemental imaging using Laser-Induced Breakdown Spectroscopy (LIBS) mapping is increasingly applied to a wide range of materials. In geomaterials, phase identification and characterization (mineralogy) are crucial for solving a variety of problems in earth sciences and mining industry.Here we applied LIBS mapping to ore samples from the world-class Kipushi deposit, Democratic Republic of Congo, because these ores are known for their great mineral complexity and economic value, especially for their high potential in critical metals such as Ge and Ga.The mineralogy of the samples was reconstructed by combining two approaches: 1) element colocalization in LIBS maps that were selected based on the knowledge of occurring mineral species at the site and 2) correlation maps obtained by applying the Interesting Features Finder (IFF) algorithm. Reconstructed minerals include chalcopyrite, bornite, chalcocite, sphalerite, galena, pyrite, tennantite-(Zn), renierite, tungstenite, betekhtinite, carrollite, gallite, and a series of non-sulphide gangue minerals (quartz, carbonate and clay minerals). SEM-EDS was used to confirm the LIBS-derived mineralogy, especially for sub-pixel inclusions.Among other results, Ge and Ga are hosted as major elements in renierite and gallite, respectively, and also as trace-elements in chalcopyrite, bornite and tungstenite (for Ge), and chalcopyrite, bornite, sphalerite and renierite (for Ga). Particular attention was paid to iron interfering with gallium at 417.20 nm, for which simple background-corrected peak intensities were compared to a more advanced chemometric method (MCR-ALS). All the results were obtained with minimal time and efforts and, while only qualitative in nature, they already provide essential information about ore texture, mineralogical composition and trace-element distribution across the ore.

Rapid qualitative and quantitative vital nutrient contents in high-altitude cultivated folklore herbal medicinal Costus roots using calibration-free LIBS

Costus Roots (CRs) (Saussurea lappa C.B. Clark- Asteraceae family) is a medicinal herb, very frequently utilized in developing countries for treating worm (nematode) infections, asthma, cholera, digestive problems and in cosmetics products. Due to its widespread consumption in developing countries to determine the health-related essential nutrients and toxic elements is of great significance. This study is highly noteworthy for prominence of therapeutic benefits of the CR roots and public awareness about their harmful effects even for producing herbal drugs derived from its roots. In this study, a very efficient, precise and rapid laser-induced breakdown spectroscopy (LIBS) method was developed to measure the content of the dried and pelletized CRs powder samples. To the best of our knowledge, this is first time that Costus roots have been studied using calibration-free LIBS (CF-LIBS) technique. Initially, the LIBS spectrometer parameters were optimized at 608.3 nm gated-time delay, 35 mJ incident laser pulse energy, and 29 mm laser-to-sample distance (LTSD)) for precise element detection before its application to the CRs analysis. The primary focus of this study is the identification and quantification of various nutrients, such as Ca, K, Mg, Si, S, P, Fe, and Na, as well as relatively toxic elements, such as Al, Ba, Mn, Zn, Sr, B, Cu, Rb, Cr, Ni, Pb, V, and Mo, in addition to Li, Ti in this native CRs herbal medicine. The concentrations of these detected elements (Ca, K, Mg, Si, S, P, Al, Fe, Na, Ti, Ba, Mn, Zn, Sr, B, Cu, Rb, Cr, Ni, Pb, V, Mo, and Li) were successfully determined as 14424, 9511, 2031, 1559, 1450, 1465, 678, 458, 59, 48, 47, 37, 37, 27, 19, 19.6, 15, 2.6, 1.5, 1.5, 1.2, 1.0 and 0.9 mg.kg−1 respectively which was in a excellent agreement with the concentrations measured using the standard ICP-OES technique.

Recent advances of light-field modulated operation in laser-induced breakdown spectroscopy

Recent advances of light-field modulated operation in laser-induced breakdown spectroscopy

Detection of chlorine in cement matrix using microwave-enhanced laser-induced breakdown spectroscopy

The detection of chloride in reinforced concrete, crucial for maintenance against damage from de-icing salt or seawater, is advanced by Laser-Induced Breakdown Spectroscopy (LIBS). This study demonstrates that integrating microwaves with LIBS enhances cement analysis, improving the signal-to-noise ratio by up to four times and extending the detection limit for chlorine to 0.17 ± 0.02 wt%. As a method, microwave-enhanced LIBS (MWE-LIBS) has existed for a decade, but in cement analysis, MWE-LIBS has been used for the first time in Cl I atomic emission measurements. This pioneering approach provides a more efficient alternative, marking a significant advancement in cement analysis.

Surface hardness imaging of a low-alloy steel using laser-induced breakdown spectroscopy

Conventional tactile hardness testing methods such as Brinell, Rockwell or Vickers rely on direct mechanical contact, which results in significant surface damage and prohibits their application to complex specimen geometries. Furthermore, the sample must have a certain thickness for tactile testing methods to be applied. In this work, we investigated the use of laser-induced breakdown spectroscopy as a fast non-quantitative alternative for visualizing surface hardness gradients. To eliminate the influence of different chemical compositions, we manually heat-treated low-alloy steel pieces cut from the same raw material and batch. By partially quenching a sample piece, we were able to obtain a hardness gradient along the longitudinal axis. We found a positive correlation between the ratio of ionic to atomic line intensities of iron (I Fe II 263.1 nm / I Fe I 358.1 nm) and the mechanical hardness of the sample surface. By scanning the surface and measuring the line intensity ratios, we were able to obtain a spatially resolved map directly correlating with the surface hardness distribution. Additionally, it was observed that the irradiation of laser pulses resulted in significant surface alterations, thereby invalidating subsequent measurements and scans at identical positions.

Exploring the viability of combined laser-induced breakdown spectroscopy and Raman spectroscopy for stratigraphic analysis of murals containing isomeric pigments: a case study on realgar and orpiment

A novel combined measurements techniques has been designed in this work, enabling the acquisition of laser-induced breakdown spectroscopy (LIBS) and Raman spectral signals at the same point on a sample. The application of this combined technique to the analysis of multi-layered mock-up blocks painted with orpiment and realgar pigments has yielded significant insights. By correlating variations in the emission line intensity of characteristic elements within the LIBS spectra with depth-specific Raman spectra, the number of laser pulses that penetrated the pigment layers has been accurately determined, thereby establishing a method to measure layer thickness. Finally, the technique wasto analysis the actual mural fragment from Mogao Cave 196, determining the types of pigment and the thickness of the pigment layers.Graphical

Tailoring particle size/morphology for the stable cathode performance of polygonal-shaped Li(Ni,Mn)2O4 single crystals

We regulate the particle size and crystallographic facet of single-crystal (SC) Li(Ni,Mn)2O4 (LNMO) cathode materials via flux-selective molten salt method. By simply adjusting Li2MoO4 or LiI as sintering aids, we synthesized size controlled SC particles, both small and large, and comparatively investigated their electrochemical behavior focusing on the lithiation/delithiation reactivity in conjunction with the particle size and surface planes. Considering the growth mechanism of a SC particles with a specific crystal plane, such particle size control is not determined solely by the synthetic condition but must also consider the interfacial energy of the crystal planes in conjunction with the fluxes what we used. While the initial charge capacity is similar, the given cathode using a small SC LNMO (using LiI) with uniform particle sizes (≤5 μm) exhibits outstanding rate capability with stable capacity retention under changing current density, which indicates stable lithium transport during the repetitive electrochemical reactions. The dependency of the impedance response with change in the electrode resistances as well as the stability during the cycle reactions in conjunction with the post-mortem Li distribution by using laser-induced breakdown spectroscopy as a function of porosity change and cell degradation are thoroughly discussed from the standpoint of regulated particle property.

Supercapacitive performance of self-assembled thin film of liquid catocene/basal plane pyrolytic graphite electrode

Reasonable design of electrode material with low cost, lightweight, and excellent electrochemical properties is of great significance for future large-scale energy storage applications. Herein, we report the electrochemical and supercapacitive behaviour of the liquid redox of catocene, 2,2’-bis(ethyl-ferroceneyl) propane, self-assembled on a basal plane pyrolitic graphite electrode in comparison to the solid ferrocene thin film in aqueous sodium sulfate electrolyte. The modified electrode surfaces were evaluated to assess the iron content and the formation of thin film using scanning electron microscopy, laser-induced breakdown spectroscopy, and attenuated total reflectance method. Also, the supercapacitive performances of the related modified electrodes were assessed and compared using cyclic voltammetry and galvanostatic charge-discharge in a three-electrode system and an asymmetric two-electrode supercapacitor system. Electro­chemical results showed that the electrode processes are diffusion-controlled with battery-like behaviour, and the liquid catocene exhibits more effective interaction with the graphite surface in comparison to solid ferrocene. The catocene surface coverage on graphite is nearly 50-75 % higher than ferrocene, leading to improved interaction and charge transfer resistance, observed in electrochemical impedance spectroscopy studies. In galvanostatic charge-discharge evaluations, the supercapacitor based on catocene modified electrode shows a specific capacitance of 141.2 F g-1 at a current density of 1.0 A g-1, with a specific energy density of 56.7 Wh kg-1 at a power density of 2.9 kW kg-1.

Laser-Induced Breakdown Spectroscopy in Mineral Exploration and Ore Processing

Laser-induced breakdown spectroscopy (LIBS) is a type of optical emission spectroscopy capable of rapid, simultaneous multi-element analysis. LIBS is effective for the analysis of atmospheric gases, geological fluids, and a broad spectrum of minerals, rocks, sediments, and soils both in and outside the traditional laboratory setting. With the recent introduction of commercial laboratory systems and handheld analyzers for use outside the laboratory for real-time in situ analysis in the field, LIBS is finding increasing application across the geosciences. This article first overviews the LIBS technique and then reviews its application in the domain of mineral exploration and ore processing, where LIBS offers some unique capabilities.

Fiberoptic Laser-Induced Breakdown Spectroscopy System for in situ Measurement in a Hazardous Environment

We report the development of a novel fiberoptic laser-induced breakdown spectroscopy (FOLIBS) system for material characterization applications. The system utilizes a 1000-µm optical fiber to transport the laser beam to remote locations for elemental analysis via laser-induced breakdown spectroscopy. Air-fiber interface damage, internal damage, and air breakdown issues during laser-fiber coupling are identified and corresponding solutions are presented. For evaluating the physical properties of the plasma generated by the FOLIBS system, spectroscopic characterization is carried out using a titanium sample. The spectral features collected from a natural uranium sample are also presented. Hence, this rapid, remote, and flexible measurement technique is promising for in situ measurements in hazardous environments in nuclear energy, nuclear safeguards, and nonproliferation applications.

Laser-Induced Breakdown Spectroscopy-Visible and Near-Infrared Spectroscopy Fusion Based on Deep Learning Network for Identification of Adulterated Polygonati Rhizoma.

The geographical origin of foods greatly influences their quality and price, leading to adulteration between high-priced and low-priced regions in the market. The rapid detection of such adulteration is crucial for food safety and fair competition. To detect the adulteration of Polygonati Rhizoma from different regions, we proposed LIBS-VNIR fusion based on the deep learning network (LVDLNet), which combines laser-induced breakdown spectroscopy (LIBS) containing element information with visible and near-infrared spectroscopy (VNIR) containing molecular information. The LVDLNet model achieved accuracy of 98.75%, macro-F measure of 98.50%, macro-precision of 98.78%, and macro-recall of 98.75%. The model, which increased these metrics from about 87% for LIBS and about 93% for VNIR to more than 98%, significantly improved the identification ability. Furthermore, tests on different adulterated source samples confirmed the model's robustness, with all metrics improving from about 87% for LIBS and 86% for VNIR to above 96%. Compared to conventional machine learning algorithms, LVDLNet also demonstrated its superior performance. The results indicated that the LVDLNet model can effectively integrate element information and molecular information to identify the adulterated Polygonati Rhizoma. This work shows that the scheme is a potent tool for food identification applications.

Laser-induced breakdown spectroscopy as a method for millimeter-scale inspection of surface flatness

A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy (LIBS) is investigated experimentally. The experiment is performed using a planished surface of an alloy steel sample to simulate its various flatness, ranging from 0 to 4.4 mm, by adjusting the laser focal plane to the surface distance with a step length of 0.2 mm. It is found that LIBS measurements are successful in inspecting the flatness differences among these simulated cases, implying that the method investigated here is feasible. It is also found that, for achieving the inspection of surface flatness within such a wide range, when univariate analysis is applied, a piecewise calibration model must be constructed. This is due to the complex dependence of plasma formation conditions on the surface flatness, which inevitably complicates the inspection procedure. To solve the problem, a multivariate analysis with the help of Back-Propagation Neural Network (BPNN) algorithms is applied to further construct the calibration model. By detailed analysis of the model performance, we demonstrate that a unified calibration model can be well established based on BPNN algorithms for unambiguous millimeter-scale range inspection of surface flatness with a resolution of about 0.2 mm.

Analysis of quartz content in muck based on artificial intelligence algorithms and laser-induced breakdown spectroscopy in TBM tunneling

Analysis of quartz content in muck based on artificial intelligence algorithms and laser-induced breakdown spectroscopy in TBM tunneling