Pub Date : 2025-11-26DOI: 10.1016/j.sab.2025.107403
Yuji Ikeda, Joey Kim Soriano
A microwave-enhanced laser-induced breakdown spectrometer (MWE-LIBS) was developed to overcome signal attenuation in conventional LIBS and achieve higher emission intensity and signal-to-noise ratio (SNR) for spectrochemical applications. Tungsten (W) was chosen as the target material due to its high melting point and technological importance. Broadband spectra confirmed strong enhancement of both neutral (W I) and ionic (W II) emissions, with SNR values increased by nearly an order of magnitude compared to standard LIBS. Temporal measurements revealed that microwave coupling sustained plasma emission well beyond the 100 μs microwave pulse duration, supporting extended excitation and recombination cycles that favored ionic transitions. The intensity enhancement factor exceeded 400 under optimum conditions, while calibration with AlW alloys demonstrated detection limits as low as 0.036 wt% (W I) and 0.062 wt% (W II). These results establish MWE-LIBS as a robust technique for trace tungsten detection with potential applications in environmental monitoring, alloy quality control, and advanced materials analysis.
{"title":"Microwave-enhanced laser-induced breakdown spectroscopy for trace tungsten analysis","authors":"Yuji Ikeda, Joey Kim Soriano","doi":"10.1016/j.sab.2025.107403","DOIUrl":"10.1016/j.sab.2025.107403","url":null,"abstract":"<div><div>A microwave-enhanced laser-induced breakdown spectrometer (MWE-LIBS) was developed to overcome signal attenuation in conventional LIBS and achieve higher emission intensity and signal-to-noise ratio (SNR) for spectrochemical applications. Tungsten (W) was chosen as the target material due to its high melting point and technological importance. Broadband spectra confirmed strong enhancement of both neutral (W I) and ionic (W II) emissions, with SNR values increased by nearly an order of magnitude compared to standard LIBS. Temporal measurements revealed that microwave coupling sustained plasma emission well beyond the 100 μs microwave pulse duration, supporting extended excitation and recombination cycles that favored ionic transitions. The intensity enhancement factor exceeded 400 under optimum conditions, while calibration with Al<img>W alloys demonstrated detection limits as low as 0.036 wt% (W I) and 0.062 wt% (W II). These results establish MWE-LIBS as a robust technique for trace tungsten detection with potential applications in environmental monitoring, alloy quality control, and advanced materials analysis.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"237 ","pages":"Article 107403"},"PeriodicalIF":3.8,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1016/j.sab.2025.107400
Muhammad Imran , Zhenhua Hu , Fang Ding , Harse Sattar , Guang-Nan Luo
In a fusion device, the high-energy ions and neutrals of impurities cause excessive erosion and redeposition of plasma-facing materials (PFMs) that lead to a reduction in fusion power output and strongly affect the divertor's lifespan. This study examined impurity types, concentration of chemical species, impurity distribution, and co-deposits on the plasma-facing components (PFCs). Collisional drag from plasma flow accelerates impurities to elevate the impact energies of impurity deposits. The test tiles of molybdenum (Mo), tungsten (W), and carbon (C) were exposed to fusion plasma in the Experimental Advanced Superconducting Tokamak (EAST) to investigate co-deposition and sputtering yield by high-energy particle bombardment and high heat flux. The redeposition patterns of local and global impurities on each test tile were analysed using laser-induced breakdown spectroscopy (LIBS) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The characterization of the test tiles reveals that enhanced gross erosion of the PFCs is caused by impurity entrainment. An uneven, thin layer co-deposited with W, Mo, Cu, Cr, Fe, Li, and Ti was observed on the test tiles. The observed high redeposition mitigates the migration of eroded materials and suppresses net erosion. Consequently, this phenomenon reduces core dilution and enhances the operational lifetime of plasma-facing components (PFCs).
{"title":"Evaluation of erosion and redeposition of irradiated plasma-facing materials by high-energy particles in fusion plasma","authors":"Muhammad Imran , Zhenhua Hu , Fang Ding , Harse Sattar , Guang-Nan Luo","doi":"10.1016/j.sab.2025.107400","DOIUrl":"10.1016/j.sab.2025.107400","url":null,"abstract":"<div><div>In a fusion device, the high-energy ions and neutrals of impurities cause excessive erosion and redeposition of plasma-facing materials (PFMs) that lead to a reduction in fusion power output and strongly affect the divertor's lifespan. This study examined impurity types, concentration of chemical species, impurity distribution, and co-deposits on the plasma-facing components (PFCs). Collisional drag from plasma flow accelerates impurities to elevate the impact energies of impurity deposits. The test tiles of molybdenum (Mo), tungsten (W), and carbon (C) were exposed to fusion plasma in the Experimental Advanced Superconducting Tokamak (EAST) to investigate co-deposition and sputtering yield by high-energy particle bombardment and high heat flux. The redeposition patterns of local and global impurities on each test tile were analysed using laser-induced breakdown spectroscopy (LIBS) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The characterization of the test tiles reveals that enhanced gross erosion of the PFCs is caused by impurity entrainment. An uneven, thin layer co-deposited with W, Mo, Cu, Cr, Fe, Li, and Ti was observed on the test tiles. The observed high redeposition mitigates the migration of eroded materials and suppresses net erosion. Consequently, this phenomenon reduces core dilution and enhances the operational lifetime of plasma-facing components (PFCs).</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107400"},"PeriodicalIF":3.8,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1016/j.sab.2025.107401
Zehua Liu , Ran Hai , Guoliang Xu , Zhenhua Hu , Rui Ding , Guizong Zuo , Xue Bai , Huace Wu , Cong Li , Ding Wu , Hongbin Ding
Boronization is a critical wall conditioning technique that improves the plasma performance of nuclear fusion devices by effectively reducing impurity levels. The team associated with the International Thermonuclear Experimental Reactor (ITER) has identified boronization as an effective means of mitigating the release of high-Z impurities. High-power long-pulse discharges conducted at the Experimental Advanced Superconducting Tokamak (EAST) have demonstrated the feasibility of ITER operations. A real-time monitoring of boron (B) layer thickness deposited on the first wall is crucial under these conditions. In this study, laser-induced breakdown spectroscopy (LIBS) has been applied to measure the thickness of ultra-thin boron films deposited on molybdenum (Mo) substrates at 5 × 10−5 mbar to simulate the EAST vacuum conditions. A series of boron films on Mo substrate samples with thicknesses ranging from 30 to 300 nm were produced by pulsed laser deposition (PLD). In ns-laser ablation, the first laser pulse penetrates the boron film and excites the underlying Mo substrate, producing stable spectral lines from boron (B II 703.19 nm) and molybdenum (Mo I 710.99 nm). A direct correlation is established between the intensity ratio of the B II 703.19 nm to Mo I 710.99 nm signals and the boron film thickness. A laser ablation model has been established and used to fit the experimental results, demonstrating consistency with the data. In addition, the relationship between the B/Mo signal intensity ratio and the relative amount of ablated material, calculated by calibration-free LIBS (CF-LIBS), has confirmed the validity of this approach. Based on experiments conducted using four different laser fluences, in-situ diagnostics of ultra–thin B film thickness in the 3.9–7.8 J/cm2 laser fluence range is recommended. The findings of this study have demonstrated the feasibility of LIBS technology for in-situ diagnostics of ultra-thin B layers as a means of monitoring the plasma-wall interaction (PWI) in fusion devices.
硼化是一种关键的壁调节技术，通过有效地降低杂质水平来改善核聚变装置的等离子体性能。与国际热核实验反应堆（ITER）相关的团队已经确定硼化是减轻高z杂质释放的有效手段。在实验先进超导托卡马克（EAST）上进行的高功率长脉冲放电证明了ITER运行的可行性。在这种条件下，实时监测沉积在第一壁的硼(B)层厚度至关重要。本研究采用激光诱导击穿光谱法（LIBS）测量了在5 × 10−5 mbar条件下沉积在钼（Mo）衬底上的超薄硼膜的厚度，以模拟EAST真空条件。采用脉冲激光沉积（PLD）技术在Mo衬底样品上制备了一系列厚度在30 ~ 300 nm之间的硼薄膜。在ns激光烧蚀中，第一个激光脉冲穿透硼膜，激发底层的Mo衬底，从硼（B II 703.19 nm）和钼（Mo I 710.99 nm）产生稳定的光谱线。硼膜厚度与B I 703.19 nm与Mo I 710.99 nm信号的强度比有直接的相关关系。建立了激光烧蚀模型，并对实验结果进行了拟合，结果与实验数据一致。此外，用免校准LIBS （CF-LIBS）计算了B/Mo信号强度比与烧蚀材料相对量的关系，证实了该方法的有效性。基于四种不同激光通量的实验，推荐在3.9 ~ 7.8 J/cm2激光通量范围内对超薄B膜厚度进行原位诊断。这项研究的结果证明了LIBS技术用于超薄B层原位诊断作为监测聚变装置中等离子体壁相互作用（PWI）的一种手段的可行性。
{"title":"Application of laser-induced breakdown spectroscopy to measure the thickness of ultra-thin boron films on molybdenum tiles","authors":"Zehua Liu , Ran Hai , Guoliang Xu , Zhenhua Hu , Rui Ding , Guizong Zuo , Xue Bai , Huace Wu , Cong Li , Ding Wu , Hongbin Ding","doi":"10.1016/j.sab.2025.107401","DOIUrl":"10.1016/j.sab.2025.107401","url":null,"abstract":"<div><div>Boronization is a critical wall conditioning technique that improves the plasma performance of nuclear fusion devices by effectively reducing impurity levels. The team associated with the International Thermonuclear Experimental Reactor (ITER) has identified boronization as an effective means of mitigating the release of high-Z impurities. High-power long-pulse discharges conducted at the Experimental Advanced Superconducting Tokamak (EAST) have demonstrated the feasibility of ITER operations. A real-time monitoring of boron (B) layer thickness deposited on the first wall is crucial under these conditions. In this study, laser-induced breakdown spectroscopy (LIBS) has been applied to measure the thickness of ultra-thin boron films deposited on molybdenum (Mo) substrates at 5 × 10<sup>−5</sup> mbar to simulate the EAST vacuum conditions. A series of boron films on Mo substrate samples with thicknesses ranging from 30 to 300 nm were produced by pulsed laser deposition (PLD). In ns-laser ablation, the first laser pulse penetrates the boron film and excites the underlying Mo substrate, producing stable spectral lines from boron (B II 703.19 nm) and molybdenum (Mo I 710.99 nm). A direct correlation is established between the intensity ratio of the B II 703.19 nm to Mo I 710.99 nm signals and the boron film thickness. A laser ablation model has been established and used to fit the experimental results, demonstrating consistency with the data. In addition, the relationship between the B/Mo signal intensity ratio and the relative amount of ablated material, calculated by calibration-free LIBS (CF-LIBS), has confirmed the validity of this approach. Based on experiments conducted using four different laser fluences, in-situ diagnostics of ultra–thin B film thickness in the 3.9–7.8 J/cm<sup>2</sup> laser fluence range is recommended. The findings of this study have demonstrated the feasibility of LIBS technology for in-situ diagnostics of ultra-thin B layers as a means of monitoring the plasma-wall interaction (PWI) in fusion devices.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107401"},"PeriodicalIF":3.8,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-21DOI: 10.1016/j.sab.2025.107399
Asmaa M. Abozied , Abdulkader M. Elmagrabi , Zein K. Heiba , Hikari Takahara , Kouichi Tsuji , Somchai Tancharakorn , Abdallah A. Shaltout
To prevent the deterioration of natural resources and support sustainable development, the valorization and recycling of various steel slags have become increasingly important. In the present work, six different types of steel slags were collected, characterized, and analyzed: electric arc furnace (EAF) slag, ladle refining furnace slag treated with Si and Al (LRF-Si and LRFAl), steel fume dust, mill scale flakes, and refractory materials waste. High resolution wavelength dispersive X-ray fluorescence (WDXRF) spectrometry with multi-dispersive crystals was used for precise quantitative elemental analysis. X-ray diffractometry was employed to identify and quantify the crystalline phases analysis within the collected samples. The analysis revealed that the mill scale flakes and EAF slags contain high concentrations of iron oxides, at approximately ∼95 % and ∼ 40 %, respectively, making them attractive for various applications. The high concentration of calcium oxides and calcium compounds in LRF slag (∼ 50 %) makes it suitable for various applications in the cement and concrete industry. Furthermore, the steel fume dust was found to contain a remarkably high concentration of zinc oxides (ZnO) reaching to ∼40 %. The high ZnO content makes the steel fume dust a promising candidate for many applications such as zinc extraction, fertilizers productions, and cosmetics.
{"title":"Valorization of steel slags through elemental and phase characterization using X-ray spectrometries","authors":"Asmaa M. Abozied , Abdulkader M. Elmagrabi , Zein K. Heiba , Hikari Takahara , Kouichi Tsuji , Somchai Tancharakorn , Abdallah A. Shaltout","doi":"10.1016/j.sab.2025.107399","DOIUrl":"10.1016/j.sab.2025.107399","url":null,"abstract":"<div><div>To prevent the deterioration of natural resources and support sustainable development, the valorization and recycling of various steel slags have become increasingly important. In the present work, six different types of steel slags were collected, characterized, and analyzed: electric arc furnace (EAF) slag, ladle refining furnace slag treated with Si and Al (LRF-Si and LRF<img>Al), steel fume dust, mill scale flakes, and refractory materials waste. High resolution wavelength dispersive X-ray fluorescence (WDXRF) spectrometry with multi-dispersive crystals was used for precise quantitative elemental analysis. X-ray diffractometry was employed to identify and quantify the crystalline phases analysis within the collected samples. The analysis revealed that the mill scale flakes and EAF slags contain high concentrations of iron oxides, at approximately ∼95 % and ∼ 40 %, respectively, making them attractive for various applications. The high concentration of calcium oxides and calcium compounds in LRF slag (∼ 50 %) makes it suitable for various applications in the cement and concrete industry. Furthermore, the steel fume dust was found to contain a remarkably high concentration of zinc oxides (ZnO) reaching to ∼40 %. The high ZnO content makes the steel fume dust a promising candidate for many applications such as zinc extraction, fertilizers productions, and cosmetics.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"237 ","pages":"Article 107399"},"PeriodicalIF":3.8,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.sab.2025.107397
Jakub Buday , Jakub Výravský , Jan Cempírek , David Prochazka , Pavel Pořízka , Jozef Kaiser
Elemental mapping of light (Li, Be, B, F) and trace elements in large-area geological samples represents an analytical challenge. Increased interest in Li and rare-element deposits results in the need for reliable mapping of light and trace elements. One of the possible solutions is laser-induced breakdown spectroscopy (LIBS) combined with sophisticated data processing. We studied four large-area (ca. 8⨯8 cm) samples from two rare-element Be-rich granitic pegmatites with moderate contents of Li + Be (Maršíkov, Czech Republic) and high contents of Li + Be+B (Rau property, Yukon, Canada). Cross-sections from the host rock to the geochemically evolved center of the pegmatite were used for direct multi-element mapping, assisted semi-automated machine-learning-based mineral identification, and tracing of magmatic, metasomatic and hydrothermal processes. From the obtained LIBS data, elemental images of individual elements of interest were produced (incl. Li and Be), and unsupervised clustering to the spectra was applied. This led to cluster images manifesting the distribution of individual matrices (i.e., minerals). The outputs of clustering were visually and statistically compared to a phase map produced by a state-of-the-art SEM-EDS-based Automated mineralogy solution (TIMA) and the results show good agreement. The study demonstrates a very good applicability of LIBS for the detection and mapping of major (Si, Al, Fe, Mg, Mn, Ca, Na), light elements (Li, Be, B, F), and trace elements (Ge, Ga, Cu, Ti, Sr, Ba) in pegmatites, discerning their specific geochemical signatures corresponding to magmatic, metasomatic, and hydrothermal stage of their evolution. The EDS-based automated mineralogy offers a higher spatial resolution in general. Still, it cannot map light elements (H, Li, Be, B) and has between one to three orders of magnitude worse detection limit for many other elements (e.g. Ga…).
{"title":"Correlative imaging of large-scale geological samples using LIBS and SEM-EDX automated mineralogy","authors":"Jakub Buday , Jakub Výravský , Jan Cempírek , David Prochazka , Pavel Pořízka , Jozef Kaiser","doi":"10.1016/j.sab.2025.107397","DOIUrl":"10.1016/j.sab.2025.107397","url":null,"abstract":"<div><div>Elemental mapping of light (Li, Be, B, F) and trace elements in large-area geological samples represents an analytical challenge. Increased interest in Li and rare-element deposits results in the need for reliable mapping of light and trace elements. One of the possible solutions is laser-induced breakdown spectroscopy (LIBS) combined with sophisticated data processing. We studied four large-area (ca. 8⨯8 cm) samples from two rare-element Be-rich granitic pegmatites with moderate contents of Li + Be (Maršíkov, Czech Republic) and high contents of Li + Be+B (Rau property, Yukon, Canada). Cross-sections from the host rock to the geochemically evolved center of the pegmatite were used for direct multi-element mapping, assisted semi-automated machine-learning-based mineral identification, and tracing of magmatic, metasomatic and hydrothermal processes. From the obtained LIBS data, elemental images of individual elements of interest were produced (incl. Li and Be), and unsupervised clustering to the spectra was applied. This led to cluster images manifesting the distribution of individual matrices (i.e., minerals). The outputs of clustering were visually and statistically compared to a phase map produced by a state-of-the-art SEM-EDS-based Automated mineralogy solution (TIMA) and the results show good agreement. The study demonstrates a very good applicability of LIBS for the detection and mapping of major (Si, Al, Fe, Mg, Mn, Ca, Na), light elements (Li, Be, B, F), and trace elements (Ge, Ga, Cu, Ti, Sr, Ba) in pegmatites, discerning their specific geochemical signatures corresponding to magmatic, metasomatic, and hydrothermal stage of their evolution. The EDS-based automated mineralogy offers a higher spatial resolution in general. Still, it cannot map light elements (H, Li, Be, B) and has between one to three orders of magnitude worse detection limit for many other elements (e.g. Ga…).</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107397"},"PeriodicalIF":3.8,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.sab.2025.107387
Sandan Wang , Wanwan Cao , Jinpeng Yuan , Lirong Wang , Liantuan Xiao , Suotang Jia
Multi-channel fluorescence detection of alkali atoms offers a robust approach to overcome the intrinsically low transition probabilities of conventional single-wavelength spectroscopy and thus enhances the development of frequency standards. Here, we experimentally realize the multi-channel fluorescence spectroscopy of the Rb 5 – 7 monochromatic two-photon transition using a single 760 nm laser. Simultaneous fluorescence emissions at 780 nm, 741 nm, 795 nm, 728 nm, and approximately 420 nm are observed, consistent with the expected decay channels. The dependence of these fluorescence intensities on laser power, polarization, and vapor temperature is systematically investigated, revealing the evolution of atomic transitions under varying experimental conditions. Pressure broadening measurements of the Rb 5 – 7 transition yield a spectral linewidth of MHz. Compared with conventional single-wavelength detection at 420 nm, multi-channel approach significantly improves the signal-to-noise ratio and provides comprehensive insights into the atomic structure. These results establish a reliable foundation for developing optical frequency standards based on the Rb 5S – 7S transition.
{"title":"Multi-channel fluorescence spectroscopy of the Rb 5S1/2 – 7S1/2 transition via monochromatic two-photon excitation","authors":"Sandan Wang , Wanwan Cao , Jinpeng Yuan , Lirong Wang , Liantuan Xiao , Suotang Jia","doi":"10.1016/j.sab.2025.107387","DOIUrl":"10.1016/j.sab.2025.107387","url":null,"abstract":"<div><div>Multi-channel fluorescence detection of alkali atoms offers a robust approach to overcome the intrinsically low transition probabilities of conventional single-wavelength spectroscopy and thus enhances the development of frequency standards. Here, we experimentally realize the multi-channel fluorescence spectroscopy of the Rb 5<span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> – 7<span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> monochromatic two-photon transition using a single 760 nm laser. Simultaneous fluorescence emissions at 780 nm, 741 nm, 795 nm, 728 nm, and approximately 420 nm are observed, consistent with the expected decay channels. The dependence of these fluorescence intensities on laser power, polarization, and vapor temperature is systematically investigated, revealing the evolution of atomic transitions under varying experimental conditions. Pressure broadening measurements of the Rb 5<span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> – 7<span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> transition yield a spectral linewidth of <span><math><mo>∼</mo></math></span> <span><math><mrow><mn>1</mn><mo>.</mo><mn>08</mn><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span> MHz. Compared with conventional single-wavelength detection at 420 nm, multi-channel approach significantly improves the signal-to-noise ratio and provides comprehensive insights into the atomic structure. These results establish a reliable foundation for developing optical frequency standards based on the Rb 5<em>S</em> – 7<em>S</em> transition.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107387"},"PeriodicalIF":3.8,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-16DOI: 10.1016/j.sab.2025.107394
Shuwen Tan , Huaiqing Qin , Chengjun Li , Weizhe Ma , Xianmao Yang , Shunchun Yao
Laser Induced Breakdown Spectroscopy (LIBS) has great potential in rapid analysis of coal quality due to the unique advantages of no complex sample pretreatment, simultaneous analysis of multiple elements and fast detection. However, due to the deviation in the precision of instrumentation, there are signal intensity difference and wavelength shift in spectra collected from different instruments. As a result, the effective quantitative analysis model based on the master instrument cannot be applied to the slave instrument, which hinders the application of LIBS. Therefore, this paper proposed a method combining wavelength shift self-calibration with feature transfer learning to improve the applicability of quantitative analysis model of coal quality. The wavelength shift between master and slave instruments was corrected by the wavelength shift self-calibration method based on the standard deviation value of characteristic peak intensity. Then, the transfer learning method based on Kernel Principal Component Analysis (KPCA) and Piecewise Direct Standardization (PDS) was used to fit the spectral features between slave instrument and master instrument. Finally, the quantitative analysis model of coal quality was established by the random forest (RF). Furthermore, the Competitive Adaptive Reweighted Sampling (CARS) feature selection method was used to select the input of model. As a result, the proposed CARS-KPCA-PDS method was able to improve the adaptability of quantitative models across different LIBS Systems. Compared with the RF model without transfer learning, the mean absolute error (MAEP) of CARS-KPCA-PDS model in predicting calorific value, carbon content and ash content were reduced by 58.32 %, 71.67 % and 77.48 %. The results demonstrated that the proposed method could improve the applicability of quantitative analysis model to different instruments and reduce the modeling cost.
{"title":"Accuracy improvement of coal quality analysis across different LIBS systems by wavelength shift self-calibration and transfer learning","authors":"Shuwen Tan , Huaiqing Qin , Chengjun Li , Weizhe Ma , Xianmao Yang , Shunchun Yao","doi":"10.1016/j.sab.2025.107394","DOIUrl":"10.1016/j.sab.2025.107394","url":null,"abstract":"<div><div>Laser Induced Breakdown Spectroscopy (LIBS) has great potential in rapid analysis of coal quality due to the unique advantages of no complex sample pretreatment, simultaneous analysis of multiple elements and fast detection. However, due to the deviation in the precision of instrumentation, there are signal intensity difference and wavelength shift in spectra collected from different instruments. As a result, the effective quantitative analysis model based on the master instrument cannot be applied to the slave instrument, which hinders the application of LIBS. Therefore, this paper proposed a method combining wavelength shift self-calibration with feature transfer learning to improve the applicability of quantitative analysis model of coal quality. The wavelength shift between master and slave instruments was corrected by the wavelength shift self-calibration method based on the standard deviation value of characteristic peak intensity. Then, the transfer learning method based on Kernel Principal Component Analysis (KPCA) and Piecewise Direct Standardization (PDS) was used to fit the spectral features between slave instrument and master instrument. Finally, the quantitative analysis model of coal quality was established by the random forest (RF). Furthermore, the Competitive Adaptive Reweighted Sampling (CARS) feature selection method was used to select the input of model. As a result, the proposed CARS-KPCA-PDS method was able to improve the adaptability of quantitative models across different LIBS Systems. Compared with the RF model without transfer learning, the mean absolute error (MAE<sub>P</sub>) of CARS-KPCA-PDS model in predicting calorific value, carbon content and ash content were reduced by 58.32 %, 71.67 % and 77.48 %. The results demonstrated that the proposed method could improve the applicability of quantitative analysis model to different instruments and reduce the modeling cost.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107394"},"PeriodicalIF":3.8,"publicationDate":"2025-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The femto- and picosecond laser induced breakdown spectroscopy (LIBS) signals statistics have been studied in detail. The picosecond laser pulse energies distribution function followed to the Gaussian profile while that for the femtosecond pulse energy slightly deviated from the normality. The same laser system generated both femto- (200 fs) and picosecond (120 ps) pulses which ablated aluminum alloy in the air. Spatially, spectrally, and temporally resolved atomic, molecular and background plasma emission signals have been quantified to reveal the LIBS signals statistics. Unlike for nanosecond ablation, femtosecond and picosecond LIBS signals were distributed normally. Plasma electron temperature was determined for each single shot plasma to estimate temperature fluctuations on observed LIBS emission signals distribution functions. It was demonstrated that plasma temperature fluctuations had little influence on femtosecond LIBS signals statistics but had a moderate impact on picosecond plasma case. The greater influence of temperature fluctuations on LIBS signals distribution function for picosecond ablation were attributed to laser-plasma interaction.
{"title":"Femto- and picosecond laser induced breakdown spectrometry signals statistics","authors":"V.N. Lednev , P.A. Sdvizhenskii , A.V. Rogachevskaya , P.A. Chizhov , A.A. Ushakov , V.V. Bulgakova , V.A. Zavozin , S.M. Pershin , A.F. Bunkin","doi":"10.1016/j.sab.2025.107393","DOIUrl":"10.1016/j.sab.2025.107393","url":null,"abstract":"<div><div>The femto- and picosecond laser induced breakdown spectroscopy (LIBS) signals statistics have been studied in detail. The picosecond laser pulse energies distribution function followed to the Gaussian profile while that for the femtosecond pulse energy slightly deviated from the normality. The same laser system generated both femto- (200 fs) and picosecond (120 ps) pulses which ablated aluminum alloy in the air. Spatially, spectrally, and temporally resolved atomic, molecular and background plasma emission signals have been quantified to reveal the LIBS signals statistics. Unlike for nanosecond ablation, femtosecond and picosecond LIBS signals were distributed normally. Plasma electron temperature was determined for each single shot plasma to estimate temperature fluctuations on observed LIBS emission signals distribution functions. It was demonstrated that plasma temperature fluctuations had little influence on femtosecond LIBS signals statistics but had a moderate impact on picosecond plasma case. The greater influence of temperature fluctuations on LIBS signals distribution function for picosecond ablation were attributed to laser-plasma interaction.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107393"},"PeriodicalIF":3.8,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.sab.2025.107395
Swetapuspa Soumyashree, Prashant Kumar
The present study aims to understand the temporal changes in emission line intensity observed in nanoparticle enhanced LIBS for experiments conducted under different ambient conditions. Although nanoparticles have been extensively used for signal enhancement in LIBS, only a handful of literature exists which discusses their behavior in low-pressure ambient. We have carried out a systematic study of signal enhancement in LIBS in presence of nanoparticles for both neutral and ionic lines in vacuum and air ambient. We have observed 2–3 times signal enhancement in the emission line intensities of neutral species in nanoparticle enhanced LIBS in both ambient. While ionic species show a similar enhancement in air for LIBS with nanoparticles, the trend is opposite in case of vacuum. The observed signal enhancements in LIBS in presence of nanoparticles for both neutral and ionic species were explained through the study of plasma parameters, temperature and electron number density. Temporal evolution of signal enhancements was compared for air and vacuum ambient for both neutral and ionic lines emphasizing the role of acquisition delay and proper selection of emission lines in case of nanoparticle enhanced LIBS.
{"title":"Investigation of signal enhancement of aluminum emission in LIBS using gold nanoparticles in air and vacuum","authors":"Swetapuspa Soumyashree, Prashant Kumar","doi":"10.1016/j.sab.2025.107395","DOIUrl":"10.1016/j.sab.2025.107395","url":null,"abstract":"<div><div>The present study aims to understand the temporal changes in emission line intensity observed in nanoparticle enhanced LIBS for experiments conducted under different ambient conditions. Although nanoparticles have been extensively used for signal enhancement in LIBS, only a handful of literature exists which discusses their behavior in low-pressure ambient. We have carried out a systematic study of signal enhancement in LIBS in presence of nanoparticles for both neutral and ionic lines in vacuum and air ambient. We have observed 2–3 times signal enhancement in the emission line intensities of neutral species in nanoparticle enhanced LIBS in both ambient. While ionic species show a similar enhancement in air for LIBS with nanoparticles, the trend is opposite in case of vacuum. The observed signal enhancements in LIBS in presence of nanoparticles for both neutral and ionic species were explained through the study of plasma parameters, temperature and electron number density. Temporal evolution of signal enhancements was compared for air and vacuum ambient for both neutral and ionic lines emphasizing the role of acquisition delay and proper selection of emission lines in case of nanoparticle enhanced LIBS.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107395"},"PeriodicalIF":3.8,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.sab.2025.107388
Xingyu Wang, Siyu Liao, Lu Chen, Jiatong Li, Lian Chen, Daqian Hei
Total reflection X-ray fluorescence (TXRF) is a key analytical technique for detecting surface metal contamination on silicon wafers. While mature commercial instruments provide excellent detection performance, they are typically large, heavy, and equipped with high-power X-ray tubes, the use of high-power X-ray tubes (The X-ray tube typically operates at a power of approximately 1500 W.) leads to increased power consumption. In this study, a compact, low-power TXRF-based spectrometer was developed specifically for wafer metal contamination detection. A new quantitative analysis method was employed to mitigate the effects associated with the use of a low-power X-ray tube. The instrument's performance was evaluated using silicon wafers deliberately contaminated with Fe, Ni, and Cu. Elemental mapping and quantitative analysis were conducted using custom Python-based software. The results demonstrate that the spectrometer offers reliable sensitivity and accuracy for detecting surface contaminants on silicon wafers.
{"title":"A compact, low-power total reflection X-ray fluorescence (TXRF) spectrometer designed for surface metal contamination analysis of silicon wafers","authors":"Xingyu Wang, Siyu Liao, Lu Chen, Jiatong Li, Lian Chen, Daqian Hei","doi":"10.1016/j.sab.2025.107388","DOIUrl":"10.1016/j.sab.2025.107388","url":null,"abstract":"<div><div>Total reflection X-ray fluorescence (TXRF) is a key analytical technique for detecting surface metal contamination on silicon wafers. While mature commercial instruments provide excellent detection performance, they are typically large, heavy, and equipped with high-power X-ray tubes, the use of high-power X-ray tubes (The X-ray tube typically operates at a power of approximately 1500 W.) leads to increased power consumption. In this study, a compact, low-power TXRF-based spectrometer was developed specifically for wafer metal contamination detection. A new quantitative analysis method was employed to mitigate the effects associated with the use of a low-power X-ray tube. The instrument's performance was evaluated using silicon wafers deliberately contaminated with Fe, Ni, and Cu. Elemental mapping and quantitative analysis were conducted using custom Python-based software. The results demonstrate that the spectrometer offers reliable sensitivity and accuracy for detecting surface contaminants on silicon wafers.</div></div>","PeriodicalId":21890,"journal":{"name":"Spectrochimica Acta Part B: Atomic Spectroscopy","volume":"235 ","pages":"Article 107388"},"PeriodicalIF":3.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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