Diagnostics and screening effects of the laser-induced plasma

Fundamentalna istraživanja interakcija laserskog zračenja i materije su naročito intenzivirana pojavom impulsnih lasera, čije je vreme trajanja svakom decenijom postajalo sve kraće. Impulsi Nd:YAG lasera, nanosekundnog trajanja, su pored brojnih primena, naročito pogodni za kreiranje plazme materijala, čije se karakteristike mogu ispitivati metodama optičke emisone spektroskopije. U ovoj disertaciji su eksperimentalno ispitivane karakteristike laserski-indukovane plazme stvorene ablacijom bakra i indijuma u zaostaloj atmosferi vazduha, vodoniku, helijumu i argonu. Primenom metoda emisione spektroskopije dijagnostikovani su plazmeni parametri; kao što su elektronska koncentracija i ekscitaciona temperatura. Na osnovu ovih podataka je sagledana dinamika prostorno-vremenskog razvoja plazme. Određeni su prostorno-vremenski intervali, u funkciji gustine snage laserskog zračenja, vrste materijala mete, vrste i pritiska ambijentalnog gasa, u kojima je optimalno posmatrati oblik i intenzitet spektralnih linija sa ciljem nalaženja atomskih parametara. Posebna pažnja je posvećena sagledavanju efekata samoapsorpcije i uslova njene minimalizacije, pa i korekciji samoapsorpcijom deformisanih profila. U cilju određivanja lokalnih vrednosti parametara u laserski-indukovanoj plazmi, korišćena je metoda zasnovana na inverznoj Abel-ovoj transformaciji. Rezonantne spektralne linije su, zbog svojih karakteristika, bile od posebnog interesa. Širenje rezonantnih spektralnih linija atoma bakra (Cu I 324.7 nm i 327.4 nm) je istraživano u spektru laserski-indukovane plazme u zaostaloj atmosferi vazduha na pritisku od 8 Pa. Na optimalnim uslovima su određeni Stark-ovi parametri ovih liniija i upoređeni sa teorijskim vrednostima. Uloga doprinosa komponenata hiperfine strukture i izotopskog efekta, rezultantnom obliku ovih spektralnih linija, je prvi put uzeta u razmatranje. Pokazano je da hiperfina struktura i izotopski efekat dodatno proširuju profile rezonantnih Cu I linija, što je značajno pri korišćenju ovih linija u dijagnostičke svrhe. Istraživanja u laserski-indukovanoj plazmi indijuma su sprovedena u zaostaloj atmosferi vazduha, vodoniku i argonu. Utvrđeno je da je ambijent argona, zbog manje izraženih prostornih i vremenskih gradijenata, izuzetno pogodan za određivanje temodinamičkih parametara plazme. Pomenuti ambijent je omogućio utvrđivanje uslova koji podrazumevaju minimalne efekte samoapsorpcije. Pod ovim uslovima su, po prvi put, eksperimentalno određeni parametri Stark-ovog širenja rezonantnih In I (410.2 nm i 451.1 nm) i jedne In II (294.1 nm) linije i upoređeni sa postojećim teorijskim vrednostima. Utvrđena je saglasnost sa dosada jedinim postojećim eksperimentalnim podacima koji se tiču pomeraja rezonantnih linija. Pokazano je da hiperfina struktura i izotopski efekat dodatno proširuju profile rezonantnih In I linija, naročito na 410.2 nm. Utvrđeno je da se doprinos hiperfine strukture na elektronskim koncentracijama iznad 1022 m-3 može zanemariti, što je značajno pri korišćenju ovih linija u dijagnostičke svrhe. Pored uzoraka metala ispitivane su karakteristike laserski-indukovane plazme hidratnih jedinjenja (CuSO4·5H2O i CaSO4·2H2O) u vidu presovanih tableta. Ovakav vid uzoraka je imao za cilj pouzdano određivanje elektronske koncentracije korišćenjem karakteristika profila vodonikovih linija iz Balmer-ove serije, za koje postoje veoma pouzdani teorijski proračuni. Pored pomenutih dijagnostičkih pogodnosti, efekat samoapsorpcije spektralnih linija je manje izražen, zbog manje koncentracije isptitivanog elementa u stvorenoj LIBS plazmi. Utvrđeno je da su hidratna jedinjenja veoma pogodna za pouzdano dijagnostikovanje parametara plazme, te je ovakav pristup predložen i za određivanje Stark-ovih parametara. U tezi su predstavljeni i rezultati istraživanja akustičkih efekata koji nastaju sa formiranjem laserski-indukovane plazme. Ispitivani su akustički odzivi proboja u vazduhu, korišćenjem različitih metala kao mete (aluminijum, bakar i zlato). Pored detaljne statističke analize opto-akustičkih signala, izvršena je vremenski integralna i vremenskirazložena analiza njihovih dominantnih učestnosti. Utvrđeno je da se ovim pristupom mogu dobiti informacije o anizotropiji i dinamici plazme, te ukazano na mogućnost korelisanja akustičkog odziva sa količinom ablirane mase. Pokazana je različitost akustičkog odziva u zavisnosti od korišćenog metala mete i sugerisane mogućnosti potencijalnih primena. Ispitivan je prag, kao i okolnosti pojavljivanja, efekata ekraniranja laserskiindukovane plazme u zavisnosti od gustine snage i talasne dužine laserskog zračenja. Utvrđeno je da pojava ekraniranja zavisi od kompleksne sprege različitih procesa, koji rezultuju apsorpcijom dela laserskog-impulsa u plazmi. Određena je vrednost praga značajnije apsorpcije za bakarni uzorak u redukovanim pristiscima helijuma, preciznim utvrđivanjem razlika mase mete pre i posle ablacije. Dobijena vrednost praga je potvrđena i metodama emisione spektroskopije na osnovu ponašanja intenziteta linija. Postignuti rezultati u ovoj tezi predstavljaju originalan doprinos proširenju postojećih rezultata u oblastima vezanim za interakciju laserskog zračenja sa materijom, kao i interakciju laserskog zračenja sa plazmom. Ovaj doprinos se ogleda i na polju atomske emisione spektroskopije, utvrđivanja atomskih parametara, ispitivanju oblika spektralnih linija, kao i prostorno-vremenske evolucije laserski-indukovane plazme. Pomenuti rezultati su i od značaja za predstojeća sveobuhvatna modeliranja u domenu kompleksnih procesa pre, tokom i posle formiranja ovakve vrste plazme.Fundamental investigations concerning laser-matter interactions have been extensively conducted ever since the invention of the pulsed laser source. Consequently, the laser pulse durations have had a constant trend of reduction in a last couple of decades. Among many other applications, Nd:YAG nanosecond pulses are frequently used for the purpose of laser-induced breakdown spectroscopy (LIBS). This thesis mainly covers the various aspects of laser induced plasma of copper and indium, created in the residual atmosphere ambient, hydrogen, helium and argon buffer gas. By using methodologies of optical emission spectroscopy, the essential thermodynamic parameters were deduced; electron density and excitation temperature. These data served as a basis for constructing a more general picture about plasma dynamics and its spatiotemporal evolution. The spatiotemporal intervals, strongly dependent on irradiance, sample structure and ambient conditions, were optimally determined with the aim of investigating spectral line shapes and corresponding atomic parameters. Special care was taken in order to detect, minimize or correct the undesirable effects of self-absorption. In order to infer local values of the mentioned plasma parameters, a method based on an inverse Abel transform, was employed. The resonance spectral lines were of a particular interest, mainly because of their unique characteristics. Spectral line broadening of the resonance copper atom lines (Cu I 324.7 nm and 327.4 nm) was investigated in the laser-induced spectrum under reduced atmospheric pressure of 8 Pa. After finding the optimal set of experimental parameters, the Stark broadening coefficients were deduced and compared to the existing theoretical values. The contributions of the hyperfine structure components and isotope effect to the resonance lines shape formation were, for the first time, taken into consideration. It is shown that the hyperfine structure and isotope effect additionally broad resonance line profiles, which is of particular interest when using these lines in various diagnostic purposes. Investigations of laser-induced indium plasma were performed under different ambient environments; reduced pressures of air, hydrogen and argon. Due to less pronounced spatiotemporal gradients and effects of self-absorption, the argon buffer gas was chosen as the most adequate environment for determination of thermodynamic plasma parameters. Under those conditions, the Stark coefficients of two resonance In I (410.2 nm and 451.1 nm) spectral lines and one ionic In II (294.1 nm) line were also determined and compared to the existing theoretical values. In terms of the estimated Stark shift directions, agreement was found with the results of one experimental work, dealing with indium resonance lines. It is shown that the hyperfine structure and isotope effect additionally broad resonance line profiles, especially in the case of 410.2 nm line. This remark is of particular interest when the electron densities exceed 1022 m-3, where HFS contributions can be safely neglected. Beside metallic samples, the characteristics of the laser-induced plasma of hydrogen containing samples (CuSO4·5H2O and CaSO4·2H2O) in the form of a pressed pellets, were also studied. This kind of matrix was chosen in order to increase reliability of electron number density determination using Stark broadened hydrogen Balmer lines, extensively investigated, both theoretically and experimentally. The effects of self-absorption are also less pronounced, due to smaller concentrations of investigated element in the sample. It is concluded that these compounds are suitable for the reliable diagnosis of plasma parameters and therefore, recommended for determination of the Stark broadening coefficients, as well. This thesis also contains results of the investigations of the laser-induced plasma acoustical response, inevitably present during the plasma formation process. The acoustical response was monitored in case of an air breakdown and also for plasmas of various metals (aluminum, copper and gold). Beside detailed statistical analysis of these opto-acoustic signals, the time-integrated and time-resolved analysis of dominant frequency components, were also performed. It is determined that this approach could be used for obtaining information about plasma anisotropy and dynamics. The possibility of correlating the plasma acoustical response with the atomised fraction of the ablated mass was also considered. The found diversities of the acoustical response depending on the used sample have imposed suggestions for the potential applications. The threshold for the onset of the significant plasma screening effects was investigated depending on the laser irradiance and wavelength. It is well known that the screening process is a result of complex interplay of various processes, favoring conditions for the absorption of the trailing part of the laser pulse. The threshold value is obtained in the case of copper sample under reduced pressures of helium atmosphere, using precise estimation of mass before and after ablation. This threshold value was additionally verified using standard emission spectroscopy probing methods, based on the spectral line behavior. The results shown in this thesis present an authentic contribution and extension of existing results in the scientific fields related to both laser-material and laser-plasma interactions. Besides, there is a degree of novelty in terms of applying new approaches concerning atomic emission spectroscopy, spectral line shape investigations, atomic parameter determination and spatiotemporal evolution of the laser-induced plasma. These results should serve as a basis for the upcoming comprehensive modeling of the complex processes before, during and after plasma formation

Diagnostics and screening effects of the laser-induced plasma

Fundamentalna istraživanja interakcija laserskog zračenja i materije su naročito intenzivirana pojavom impulsnih lasera, čije je vreme trajanja svakom decenijom postajalo sve kraće. Impulsi Nd:YAG lasera, nanosekundnog trajanja, su pored brojnih primena, naročito pogodni za kreiranje plazme materijala, čije se karakteristike mogu ispitivati metodama optičke emisone spektroskopije. U ovoj disertaciji su eksperimentalno ispitivane karakteristike laserski-indukovane plazme stvorene ablacijom bakra i indijuma u zaostaloj atmosferi vazduha, vodoniku, helijumu i argonu. Primenom metoda emisione spektroskopije dijagnostikovani su plazmeni parametri; kao što su elektronska koncentracija i ekscitaciona temperatura. Na osnovu ovih podataka je sagledana dinamika prostorno-vremenskog razvoja plazme. Određeni su prostorno-vremenski intervali, u funkciji gustine snage laserskog zračenja, vrste materijala mete, vrste i pritiska ambijentalnog gasa, u kojima je optimalno posmatrati oblik i intenzitet spektralnih linija sa ciljem nalaženja atomskih parametara. Posebna pažnja je posvećena sagledavanju efekata samoapsorpcije i uslova njene minimalizacije, pa i korekciji samoapsorpcijom deformisanih profila. U cilju određivanja lokalnih vrednosti parametara u laserski-indukovanoj plazmi, korišćena je metoda zasnovana na inverznoj Abel-ovoj transformaciji. Rezonantne spektralne linije su, zbog svojih karakteristika, bile od posebnog interesa. Širenje rezonantnih spektralnih linija atoma bakra (Cu I 324.7 nm i 327.4 nm) je istraživano u spektru laserski-indukovane plazme u zaostaloj atmosferi vazduha na pritisku od 8 Pa. Na optimalnim uslovima su određeni Stark-ovi parametri ovih liniija i upoređeni sa teorijskim vrednostima. Uloga doprinosa komponenata hiperfine strukture i izotopskog efekta, rezultantnom obliku ovih spektralnih linija, je prvi put uzeta u razmatranje. Pokazano je da hiperfina struktura i izotopski efekat dodatno proširuju profile rezonantnih Cu I linija, što je značajno pri korišćenju ovih linija u dijagnostičke svrhe. Istraživanja u laserski-indukovanoj plazmi indijuma su sprovedena u zaostaloj atmosferi vazduha, vodoniku i argonu. Utvrđeno je da je ambijent argona, zbog manje izraženih prostornih i vremenskih gradijenata, izuzetno pogodan za određivanje temodinamičkih parametara plazme. Pomenuti ambijent je omogućio utvrđivanje uslova koji podrazumevaju minimalne efekte samoapsorpcije. Pod ovim uslovima su, po prvi put, eksperimentalno određeni parametri Stark-ovog širenja rezonantnih In I (410.2 nm i 451.1 nm) i jedne In II (294.1 nm) linije i upoređeni sa postojećim teorijskim vrednostima. Utvrđena je saglasnost sa dosada jedinim postojećim eksperimentalnim podacima koji se tiču pomeraja rezonantnih linija. Pokazano je da hiperfina struktura i izotopski efekat dodatno proširuju profile rezonantnih In I linija, naročito na 410.2 nm. Utvrđeno je da se doprinos hiperfine strukture na elektronskim koncentracijama iznad 1022 m-3 može zanemariti, što je značajno pri korišćenju ovih linija u dijagnostičke svrhe. Pored uzoraka metala ispitivane su karakteristike laserski-indukovane plazme hidratnih jedinjenja (CuSO4·5H2O i CaSO4·2H2O) u vidu presovanih tableta. Ovakav vid uzoraka je imao za cilj pouzdano određivanje elektronske koncentracije korišćenjem karakteristika profila vodonikovih linija iz Balmer-ove serije, za koje postoje veoma pouzdani teorijski proračuni. Pored pomenutih dijagnostičkih pogodnosti, efekat samoapsorpcije spektralnih linija je manje izražen, zbog manje koncentracije isptitivanog elementa u stvorenoj LIBS plazmi. Utvrđeno je da su hidratna jedinjenja veoma pogodna za pouzdano dijagnostikovanje parametara plazme, te je ovakav pristup predložen i za određivanje Stark-ovih parametara. U tezi su predstavljeni i rezultati istraživanja akustičkih efekata koji nastaju sa formiranjem laserski-indukovane plazme. Ispitivani su akustički odzivi proboja u vazduhu, korišćenjem različitih metala kao mete (aluminijum, bakar i zlato). Pored detaljne statističke analize opto-akustičkih signala, izvršena je vremenski integralna i vremenskirazložena analiza njihovih dominantnih učestnosti. Utvrđeno je da se ovim pristupom mogu dobiti informacije o anizotropiji i dinamici plazme, te ukazano na mogućnost korelisanja akustičkog odziva sa količinom ablirane mase. Pokazana je različitost akustičkog odziva u zavisnosti od korišćenog metala mete i sugerisane mogućnosti potencijalnih primena. Ispitivan je prag, kao i okolnosti pojavljivanja, efekata ekraniranja laserskiindukovane plazme u zavisnosti od gustine snage i talasne dužine laserskog zračenja. Utvrđeno je da pojava ekraniranja zavisi od kompleksne sprege različitih procesa, koji rezultuju apsorpcijom dela laserskog-impulsa u plazmi. Određena je vrednost praga značajnije apsorpcije za bakarni uzorak u redukovanim pristiscima helijuma, preciznim utvrđivanjem razlika mase mete pre i posle ablacije. Dobijena vrednost praga je potvrđena i metodama emisione spektroskopije na osnovu ponašanja intenziteta linija. Postignuti rezultati u ovoj tezi predstavljaju originalan doprinos proširenju postojećih rezultata u oblastima vezanim za interakciju laserskog zračenja sa materijom, kao i interakciju laserskog zračenja sa plazmom. Ovaj doprinos se ogleda i na polju atomske emisione spektroskopije, utvrđivanja atomskih parametara, ispitivanju oblika spektralnih linija, kao i prostorno-vremenske evolucije laserski-indukovane plazme. Pomenuti rezultati su i od značaja za predstojeća sveobuhvatna modeliranja u domenu kompleksnih procesa pre, tokom i posle formiranja ovakve vrste plazme.Fundamental investigations concerning laser-matter interactions have been extensively conducted ever since the invention of the pulsed laser source. Consequently, the laser pulse durations have had a constant trend of reduction in a last couple of decades. Among many other applications, Nd:YAG nanosecond pulses are frequently used for the purpose of laser-induced breakdown spectroscopy (LIBS). This thesis mainly covers the various aspects of laser induced plasma of copper and indium, created in the residual atmosphere ambient, hydrogen, helium and argon buffer gas. By using methodologies of optical emission spectroscopy, the essential thermodynamic parameters were deduced; electron density and excitation temperature. These data served as a basis for constructing a more general picture about plasma dynamics and its spatiotemporal evolution. The spatiotemporal intervals, strongly dependent on irradiance, sample structure and ambient conditions, were optimally determined with the aim of investigating spectral line shapes and corresponding atomic parameters. Special care was taken in order to detect, minimize or correct the undesirable effects of self-absorption. In order to infer local values of the mentioned plasma parameters, a method based on an inverse Abel transform, was employed. The resonance spectral lines were of a particular interest, mainly because of their unique characteristics. Spectral line broadening of the resonance copper atom lines (Cu I 324.7 nm and 327.4 nm) was investigated in the laser-induced spectrum under reduced atmospheric pressure of 8 Pa. After finding the optimal set of experimental parameters, the Stark broadening coefficients were deduced and compared to the existing theoretical values. The contributions of the hyperfine structure components and isotope effect to the resonance lines shape formation were, for the first time, taken into consideration. It is shown that the hyperfine structure and isotope effect additionally broad resonance line profiles, which is of particular interest when using these lines in various diagnostic purposes. Investigations of laser-induced indium plasma were performed under different ambient environments; reduced pressures of air, hydrogen and argon. Due to less pronounced spatiotemporal gradients and effects of self-absorption, the argon buffer gas was chosen as the most adequate environment for determination of thermodynamic plasma parameters. Under those conditions, the Stark coefficients of two resonance In I (410.2 nm and 451.1 nm) spectral lines and one ionic In II (294.1 nm) line were also determined and compared to the existing theoretical values. In terms of the estimated Stark shift directions, agreement was found with the results of one experimental work, dealing with indium resonance lines. It is shown that the hyperfine structure and isotope effect additionally broad resonance line profiles, especially in the case of 410.2 nm line. This remark is of particular interest when the electron densities exceed 1022 m-3, where HFS contributions can be safely neglected. Beside metallic samples, the characteristics of the laser-induced plasma of hydrogen containing samples (CuSO4·5H2O and CaSO4·2H2O) in the form of a pressed pellets, were also studied. This kind of matrix was chosen in order to increase reliability of electron number density determination using Stark broadened hydrogen Balmer lines, extensively investigated, both theoretically and experimentally. The effects of self-absorption are also less pronounced, due to smaller concentrations of investigated element in the sample. It is concluded that these compounds are suitable for the reliable diagnosis of plasma parameters and therefore, recommended for determination of the Stark broadening coefficients, as well. This thesis also contains results of the investigations of the laser-induced plasma acoustical response, inevitably present during the plasma formation process. The acoustical response was monitored in case of an air breakdown and also for plasmas of various metals (aluminum, copper and gold). Beside detailed statistical analysis of these opto-acoustic signals, the time-integrated and time-resolved analysis of dominant frequency components, were also performed. It is determined that this approach could be used for obtaining information about plasma anisotropy and dynamics. The possibility of correlating the plasma acoustical response with the atomised fraction of the ablated mass was also considered. The found diversities of the acoustical response depending on the used sample have imposed suggestions for the potential applications. The threshold for the onset of the significant plasma screening effects was investigated depending on the laser irradiance and wavelength. It is well known that the screening process is a result of complex interplay of various processes, favoring conditions for the absorption of the trailing part of the laser pulse. The threshold value is obtained in the case of copper sample under reduced pressures of helium atmosphere, using precise estimation of mass before and after ablation. This threshold value was additionally verified using standard emission spectroscopy probing methods, based on the spectral line behavior. The results shown in this thesis present an authentic contribution and extension of existing results in the scientific fields related to both laser-material and laser-plasma interactions. Besides, there is a degree of novelty in terms of applying new approaches concerning atomic emission spectroscopy, spectral line shape investigations, atomic parameter determination and spatiotemporal evolution of the laser-induced plasma. These results should serve as a basis for the upcoming comprehensive modeling of the complex processes before, during and after plasma formation

Stark broadening measurements in plasmas produced by laser ablation of hydrogen containing compounds

8th Euro-Mediterranean Symposium on Laser Induced Breakdown Spectroscopy (EMSLIBS), Linz, AUSTRIA, SEP 14-18, 2015International audienceWe present a method for the measurement of Stark broadening parameters of atomic and ionic spectral lines based on laser ablation of hydrogen containing compounds. Therefore, plume emission spectra, recorded with an echelle spectrometer coupled to a gated detector, were compared to the spectral radiance of a plasma in local thermal equilibrium. Producing material ablation with ultraviolet nanosecond laser pulses in argon at near atmospheric pressure, the recordings take advantage of the spatially uniform distributions of electron density and temperature within the ablated vapor. By changing the delay between laser pulse and detector gate, the electron density could be varied by more than two orders of magnitude while the temperature was altered in the range from 6,000 to 14,000 K. The Stark broadening parameters of transitions were derived from their simultaneous observation with the hydrogen Balmer alpha line. In addition, assuming a linear increase of Stark widths and shifts with electron density for non-hydrogenic lines, our measurements indicate a change of the Stark broadening-dependence of H α over the considered electron density range. The presented results obtained for hydrated calcium sulfate (CaSO 4 ·2H 2 O) can be extended to any kind of hydrogen containing compounds

Spectroscopic study of the laser-induced indium plasma

We report experimental research of the laser-produced indium plasma in hydrogen, argon and residual atmospheric ambient conditions. Note on general plasma behavior and morphology is presented. On the basis of intensity ratio of the two intense neutral resonance spectral lines (In I 410.2 nm and 451.1 nm), self-absorption was found to be almost negligible in case of argon environment at a pressure of 6650 Pa. Under these conditions, the first Stark widths (W) and shifts (d) measurements were performed as well. The resulting synthetic Lorentz profiles, based on the hyperfine structure of these two lines and corresponded W values, were calculated in order to reproduce measured Wm in case of particular electron temperature (T) and number density (N). These results should be of interest to the upcoming theoretical calculations concerning neutral indium spectral lines and also for various diagnostic applications

Role of spectroscopic diagnostics in studying nanosecond laser-plasma interaction

We studied the impact of varying the intensity of Nd:YAG nanosecond 1.06 μm laser radiation on the morphology and internal structure of copper plasma plumes were examined. Standard diagnostic techniques used to deduce axial distributions of electron density and temperature revealed effects of a pronounced plasma screening regime. Methods of fast imaging spectroscopy are used to examine the transition from weak- to high-screening plasma, applying irradiance on the order of 109 W cm-2 in helium atmosphere. Behavior of both ionized and neutral species was observed up to 1 μs after the laser pulse. Showing significant differences with an increase of laser irradiance, the change in plasma propagation mechanisms is attributed to internal shockwave dynamics within the plasma plume. Implications of observed behavior to plasma uniformity can affect diagnostics, and are relevant to both modeling and applications

Progress in calibration-free laser-induced breakdown spectroscopy

International audienceDirect elemental analysis of materials via modeling of the laser-produced plasma emission attracted great interest since the introduction of calibration-free laser-induced breakdown spectroscopy in 1999. However, the large number of different approaches and their validation in diverse experimental conditions make it difficult to evaluate the achievable performance with this revolutionary type of analytical measurements. The purpose of the present paper is to provide a critical review of the development of calibration-free LIBS, to highlight the progress being achieved until now, and to estimate its available analytical performance. Based on the identification of the principal sources of measurement uncertainty, solutions are proposed to further improve the accuracy in order to bring calibration-free LIBS to the standard of fully recognized analytical methods

Overview of existing information on important closed (or in closing phase) and abandoned mining waste sites and related mines in Slovenia

The presented work provides a comprehensive inventory of data on closed (or in closing phase) and abandoned underground and surface mines and mining waste sites in Slovenia, collected within the framework of the Geological Survey of Slovenia (GeoZS) over the last two decades. Furthermore, a detailed overview of information on closed and abandoned mining waste sites in Slovenia is given. In order to establish the inventory, a definition of the work methodology, a comprehensive research of the archived and published literature, and the harmonisation and management of the collected data was carried out. Based on a selected methodology, the inventory contains information on 33 metal mines, 43 coal mines, 51 non-metallic mineral resource mines, 156 waste sites from metal mines and 18 waste sites from coal mines. The inventory is in the open access Google Earth file. It provides a basis for further research into the environmental impact of mining waste, which has been carried out since the EU Directive on the management of waste from extractive industries (Directive 2006/21/EC hereafter) was adopted into national law. In general, about 11,621,333 m3 of waste sites from metal mines and 76,188,000 m3 of waste sites from coal mines are covering about 678 hectares of Slovenian territory. More than half (64 %) of the waste from metal mines was produced in the Mežica lead and zinc mine, while the other two mines with a still significant share of produced waste were the Idrija mercury mine (18 %) and the Žirovski vrh uranium mine (15 %). Among the closed coal mines, the largest amount (46 %) of waste was generated by the coal mine Trbovlje-Hrastnik, while the other two coal mines with still significant share of waste produced were Kočevje (28 %) and Kanižarica (17 %)

Ideal radiation source for plasma spectroscopy generated by laser ablation

International audienceLaboratory plasmas inherently exhibit temperature and density gradients leading to complex investigations. We show that plasmas generated by laser ablation can constitute a robust exception to this. Supported by emission features not observed with other sources, we achieve plasmas of various compositions which are both uniform and in local thermodynamic equilibrium. These properties characterize an ideal radiation source opening multiple perspectives in plasma spectroscopy. The finding also constitutes a breakthrough in the analytical field as fast analyses of complex materials become possible

Remote Detection of Uranium Using Self-Focusing Intense Femtosecond Laser Pulses

Optical measurement techniques can address certain important challenges associated with nuclear safety and security. Detection of uranium over long distances presents one such challenge that is difficult to realize with traditional ionizing radiation detection, but may benefit from the use of techniques based on intense femtosecond laser pulses. When a high-power laser pulse propagates in air, it experiences collapse and confinement into filaments over an extended distance even without external focusing. In our experiments, we varied the initial pulse chirp to optimize the emission signal from the laser-produced uranium plasma at an extended distance. While the ablation efficiency of filaments formed by self-focusing is known to be significantly lower when compared to filaments produced by external focusing, we show that filaments formed by self-focusing can still generate luminous spectroscopic signatures of uranium detectable within seconds over a 10-m range. The intensity of uranium emission varies periodically with laser chirp, which is attributed to the interplay among self-focusing, defocusing, and multi-filament fragmentation along the beam propagation axis. Grouping of multi-filaments incident on target is found to be correlated with the uranium emission intensity. The results show promise towards long-range detection, advancing the diagnostics and analytical capabilities in ultrafast laser-based spectroscopy of high-Z elements

Addition Reactions Across Polyfluoroalkyl and Perfluoroalkyl Substituted CO and CN Multiple Bond Systems

Burger K, Sewald N, Schierlinger C, Brunner E. Addition Reactions Across Polyfluoroalkyl and Perfluoroalkyl Substituted CO and CN Multiple Bond Systems. In: Hudlický M, Paviath AE, eds. Chemistry of organic fluorine compounds II. A critical review. ACS Monograph. Vol 187. Washington DC: ACS; 1995: 840-887