Alexander Bolshakov | University of Massachusetts Amherst (original) (raw)

Papers by Alexander Bolshakov

Technical Physics, 2008

A vertical-cavity surface-emitting diode laser is used as a tunable emission source to measure th... more A vertical-cavity surface-emitting diode laser is used as a tunable emission source to measure the radius-integrated gas temperature in an inductively coupled plasma reactor. Relevant data are obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon-nitrogen (3, 45, and 90% N 2 in Ar) plasmas in the pressure range 0.5-70.0 Pa and at an inductive power of 100 and 300 W. The results are compared with the rotational temperature of molecular nitrogen. The difference between the integrated rotational and Doppler temperatures is attributed to the nonuniform spatial distributions of the temperature and thermometric atomic and molecular species (Ar* and). These distributions are computed in terms of the nonequilibrium hydrodynamic model of plasma. The objective of this work is to develop a contactless (nonintrusive) technique for measuring the temperature and concentration of different particles in the reactor with a microsensor.

Plasma Sources Science and Technology, 2004

A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission ... more A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission source for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3%, 45%, and 90% N2 in Ar) at pressures of 0.5–70 Pa and inductive powers of 100 and 300 W. The results were compared to the rotational temperature derived from the rotational temperature derived from the N2 emission at the (0,0) vibrational transition of the C 3Πu–B 3Πg system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on the conditions. A two-dimensional, three-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable us to track the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.

Journal of Applied Physics, 2004

In order to study the sterilization capabilities of radio frequency driven low pressure oxygen pl... more In order to study the sterilization capabilities of radio frequency driven low pressure oxygen plasmas, the radiative emission was recorded at various pressures and input powers. A distinct transition from the bright mode (primarily inductively coupled) to a dim mode (primarily capacitively coupled) was observed as the pressure was increased and/or the power decreased. The data was further analyzed to estimate the electron temperature, rotational and vibrational temperatures, and various species concentrations. Based on the diffusion and rovibrational relaxation times, it is concluded that the rotational temperatures can be assumed to be in equilibrium with the translational temperature. The ions are produced ``hot'' and have little time to get equilibrated with the translational temperature. It is further determined that in the bright mode, which is more effective in microbe sterilization, the translational/rotational temperatures are in the 650-850 K range, the electron temperatures are low (3.5-4.5 eV), and the concentrations of atomic O and atomic metastables are at 1 order of magnitude higher than in the dim mode.

Biotechnology Progress, 2003

The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were asses... more The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, and biochemical techniques. In low power O 2 plasma (∼25 W, ∼45 mTorr, 90 min), D. radiodurans, a radiation-resistant bacterium, showed a 99.999% reduction in bioburden. In higher power O 2 plasma (100 W and 500 mTorr), the reduction rate increased about 10-fold and observation by atomic force microscopy showed significant damage to the cell. Damage to cellular lipids, proteins, and chromosome was indicated by losses of infrared spectroscopic peaks at 2930, 1651, 1538, and 1245 cm-1 , respectively. In vitro experiments show that O 2 plasmas induce DNA strand scissions and cross-linking as well as reduction of enzyme activity. The observed degradation and removal of biomolecules was power-dependent. Exposures to 200 W at 500 mTorr removed biomolecules to below detection limits in 60 s. Emission spectroscopy indicated that D. radiodurans cells were volatilized into CO 2 , CO, N 2 , and H 2 O, confirming that these plasmas were removing complex biological matter from surfaces. A CO 2 plasma was not as effective as the O 2 plasma, indicating the importance of plasma composition and the dominant role of chemical degradation. Together, these findings have implications for NASA planetary protection schemes and for the contamination of Mars.

AIAA Journal, 2004

An oxygen plasma sustained at 13.56 MHz in a standardized reactor with a planar induction coil wa... more An oxygen plasma sustained at 13.56 MHz in a standardized reactor with a planar induction coil was used for biological decontamination experiments. Optical emission, mass spectrometry, Langmuir probe, and electrical measurements were applied to detection of chemical species and ion-energy and ux analysis. These diagnostics identi ed a plasma-mode transition in the range of 13-67-Pa pressure and 100-330-W power to the induction coil. At higher pressure and lower power, the plasma was sustained in a dim mode (primarily by stray capacitive coupling). A primarily inductive bright mode was attained at lower pressure and higher power. The coupling mode of plasma operation was then monitored by emission spectroscopy on an analogous, scaled-down reactor for biological degradation tests. Plasmid DNA degradation ef cacies were compared in both plasma modes. DNA removal was »25% more ef cient in the inductively coupled mode than in the capacitively coupled mode at the same power. The fast degradation was attributed to synergetic mechanisms (photoand ion-assisted etching by oxygen atoms and perhaps O ¤ 2 metastable molecules). Volatilization rates of the decomposition products (CO 2 , CO, N 2 , OH, H) evolving from the microbial (Deinococcus radiodurans) and polypeptide samples exposed to the plasma were compared. A plasma sustained in Martian atmosphere is considered.

SPIE Proceedings, 2004

A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing h... more A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N 2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N 2 emission at the (0,0) transition of the C 3 Π u-B 3 Π g system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N 2 *) that varied depending on conditions. A twodimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro-and nano-fabrication plasma processing, thus enabling the diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable tracking the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.

Imaging and Applied Optics Technical Papers, 2012

Abstract Laser ablation offers rapid micro-analysis with spatial resolution~ 10 nm in depth,~ 3 μ... more Abstract Laser ablation offers rapid micro-analysis with spatial resolution~ 10 nm in depth,~ 3 μm lateral. Structured materials are mapped, depth-profiled for elemental and isotopic composition using LIBS or LA-ICP-MS without dissolving samples. Molecular structure can be inferred by chemometric processing.

Laser-Induced Breakdown Spectroscopy, 2020

Abstract This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of intere... more Abstract This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of interest are applications in diverse fields that include plasma diagnostics, combustion diagnostics, molecular plasma spectroscopy, and selected astrophysics spectra analyses. Laser ablation molecular isotopic spectrometry (LAMIS) reveals favorable measurement opportunities for identification of atomic isotope compared to direct isotope spectroscopy. For selected molecules of different atomic isotope composition, or for isotopologues, the presented summary discusses LAMIS advantages. LIBS experiments convey formation of diatomic molecules primarily due to recombination. The analysis of diatomic emission spectra reveals excitation temperatures up to 10 kK following laser-induced optical breakdown. Cyanide (CN), aluminum monoxide (AlO), titanium monoxide, Swan bands of C2, and hydroxyl molecules are frequently recorded in nanosecond LIBS investigations over and above the usual atomic emission spectra. The CN molecule occurs within the first few hundred nanoseconds after optical breakdown, and Abel inversion of CN line-of-sight data determines the spatial distributions of molecular signals. For nanosecond LIBS, expansion dynamics and shockwave phenomena explain the measured radial distributions for CN and also for hydrogen. Chemical equilibrium distribution computations assess deviation from thermodynamic equilibrium. This chapter also communicates measurements of AlO ablation spectra and associated analysis with line strength data. Analysis of astrophysics C2 Swan spectra provides further challenges, but in turn can serve as a gauge for chemical analysis with molecular LIBS.

Journal of Analytical Atomic Spectrometry, 2017

This is the original research on the significant intensity enhancement in atomic and molecular em... more This is the original research on the significant intensity enhancement in atomic and molecular emission in laser ablation plasma reheated by an electric pulse.

Physics World, Apr 1, 2013

"Bolshakov and co-workers have developed a technique called LAMIS - laser ablati... more "Bolshakov and co-workers have developed a technique called LAMIS - laser ablation molecul a r isotopic spectrometry that would extend the capabilities of one of Curiosity's existing instruments, ChemCam, to perform optical isotopic analysis."

Spectrochimica Acta Part B: Atomic Spectroscopy, 2016

In this study laser induced breakdown spectroscopy (LIBS) is used for elemental characterization ... more In this study laser induced breakdown spectroscopy (LIBS) is used for elemental characterization of outcrop samples from the Marcellus Shale. Powdered samples were pressed to form pellets and used for LIBS analysis. Partial least squares regression (PLS-R) and univariate calibration curves were used for quantification of analytes. The matrix effect is substantially reduced using the partial least squares calibration method. Predicted results with LIBS are compared to ICP-OES results for Si, Al, Ti, Mg, and Ca. As for C, its results are compared to those obtained by a carbon analyzer. Relative errors of the LIBS measurements are in the range of 1.7 to 12.6%. The limits of detection (LOD) obtained for Si, Al, Ti, Mg and Ca are 60.9, 33.0, 15.6, 4.2 and 0.03 ppm, respectively. An LOD of 0.4wt% was obtained for carbon. This study shows that the LIBS method can provide a rapid analysis of shale samples and can potentially benefit depleted gas shale carbon storage research.

The objective of a virtual impactor is to separate out the larger particles in a flow from the sm... more The objective of a virtual impactor is to separate out the larger particles in a flow from the smaller particles in such a way that both sizes of particles are available for sampling. A jet of particle-laden air is accelerated toward a collection probe so that a small gap exists between the acceleration nozzle and the probe. A vacuum is applied to deflect a major portion of the airstream away form the collection probe. Particles larger than a certain size have sufficient momentum so that they cross the deflected streamlines and enter the collection probe, whereas smaller particles follow the deflected streamlines. The result is that the collection probe will contain a higher concentration of larger particles than is in the initial airstream. Typically, virtual impactors are high-flow devices used to separate out particles greater than several microns in diameter. We have developed a special virtual impactor to concentrate aerosol particles of diameters between 0.5 to 1 micron for th...

Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVII, 2012

ABSTRACT Laser induced plasma can be used for rapid optical diagnostics of electronic, optical, e... more ABSTRACT Laser induced plasma can be used for rapid optical diagnostics of electronic, optical, electro-optical, electromechanical and other structures. Plasma monitoring and diagnostics can be realized during laser processing in real time by means of measuring optical emission that originates from the pulsed laser-material interaction. In post-process applications, eg, quality assurance and quality control, surface raster scanning and depth profiling can be realized with high spatial resolution (~ 10 nm in depth and~ 3 µm lateral). ...

Sensors and Systems for Space Applications V, 2012

abstract A concept of a compact device for analyzing key isotopic composition in surface material... more abstract A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a ...

Spectrochimica Acta Part B: Atomic Spectroscopy, 1997

Inductively coupled plasma (ICP) discharges in chlorine, argon, and their mixtures sustained insi... more Inductively coupled plasma (ICP) discharges in chlorine, argon, and their mixtures sustained inside a spherical quartz container at atmospheric pressure have been investigated. Continua of radiative attachment of a free electron to a chlorine atom in ICP are elucidated and are utilized to derive a spatial profile of electron temperature. A qualitative picture of elementary processes in enclosed ICP is given. Differences between electron and gas temperatures are discussed. Electron temperature is maximum in a periphery layer near the induction coil that is chosen for impurity determination. Concentrations of carbon and metal impurities are estimated.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2011

Russian Chemical Reviews, 2006

The trends in the development of five main branches of The trends in the development of five main... more The trends in the development of five main branches of The trends in the development of five main branches of atomic spectrometry, atomic spectrometry, viz viz., absorption, emission, mass, fluores-., absorption, emission, mass, fluorescence and ionisation spectrometry, are analysed. The advantages cence and ionisation spectrometry, are analysed. The advantages and drawbacks of various techniques in atomic spectrometry are and drawbacks of various techniques in atomic spectrometry are considered. Emphasised are the applications of analytical plasma-considered. Emphasised are the applications of analytical plasmaand laser-based methods. The problems and prospects in the and laser-based methods. The problems and prospects in the development in respective fields of analytical instrumentation development in respective fields of analytical instrumentation are discussed. The bibliography includes 279 references are discussed. The bibliography includes 279 references. .

Journal of Analytical Atomic Spectrometry, 2011

An overview of laser plasma spectrochemistry is presented to demonstrate its wide range of capabi... more An overview of laser plasma spectrochemistry is presented to demonstrate its wide range of capabilities. Laser plasmas offer the ability to perform elemental, isotopic, molecular, quantitative and qualitative sample analysis with sub-micron spatial resolution, and each feature can be measured at standoff distances. Obviously, these attributes are not all achievable at the same time, but they can be optimized for specific applications. This manuscript gives a sampling (pun intended) of the research in our group that has ...

NASA Tech Briefs; www.techbriefs.com/component/content/article/15174, Nov 1, 2012

ABSTRACT A new elegant technology was born and branded as Laser Ablation Molecular Isotopic Spect... more ABSTRACT A new elegant technology was born and branded as Laser Ablation Molecular Isotopic Spectrometry (LAMIS). LAMIS shares all the same technical benefits of its predecessor Laser Induced Breakdown Spectroscopy (LIBS), including rapid analysis and the elimination of sample preparation. LIBS measures atomic emission spectra during the first microsecond after an ablation pulse. LAMIS measurement follows later when the plasma cools down. Then molecules form in the plasma and the intensity of molecular spectra increases and persists for some while. Molecular spectra are useful for isotopic analysis because the isotopic shifts in molecular emission are significantly larger than in atomic spectra. There is no need for a large high-resolution spectrometer; a compact spectrometer can resolve isotopic spectra. LIBS and LAMIS techniques can be accomplished on the same instrument, thus extending ChemCam with a new dimension of isotopic analysis. ChemCam is a scientific instruments on board of the automatic Mars Science Laboratory rover “Curiosity.”

One of the most pressing applications for LIBS is the detection of toxic metals in various matric... more One of the most pressing applications for LIBS is the detection of toxic metals in various matrices. For example, sensitive and rapid determination of lead remains a substantial challenge for other techniques. X-ray fluorescence (XRF) has often been the method of choice because this technique requires no lengthy sample preparation. However, XRF analysis can take 1 to~ 10 min per sample in order to accumulate a detectable signal from low-parts-per-million concentrations of lead. And it can fail to detect even higher ...

Technical Physics, 2008

A vertical-cavity surface-emitting diode laser is used as a tunable emission source to measure th... more A vertical-cavity surface-emitting diode laser is used as a tunable emission source to measure the radius-integrated gas temperature in an inductively coupled plasma reactor. Relevant data are obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon-nitrogen (3, 45, and 90% N 2 in Ar) plasmas in the pressure range 0.5-70.0 Pa and at an inductive power of 100 and 300 W. The results are compared with the rotational temperature of molecular nitrogen. The difference between the integrated rotational and Doppler temperatures is attributed to the nonuniform spatial distributions of the temperature and thermometric atomic and molecular species (Ar* and). These distributions are computed in terms of the nonequilibrium hydrodynamic model of plasma. The objective of this work is to develop a contactless (nonintrusive) technique for measuring the temperature and concentration of different particles in the reactor with a microsensor.

Plasma Sources Science and Technology, 2004

A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission ... more A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission source for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3%, 45%, and 90% N2 in Ar) at pressures of 0.5–70 Pa and inductive powers of 100 and 300 W. The results were compared to the rotational temperature derived from the rotational temperature derived from the N2 emission at the (0,0) vibrational transition of the C 3Πu–B 3Πg system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on the conditions. A two-dimensional, three-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable us to track the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.

Journal of Applied Physics, 2004

In order to study the sterilization capabilities of radio frequency driven low pressure oxygen pl... more In order to study the sterilization capabilities of radio frequency driven low pressure oxygen plasmas, the radiative emission was recorded at various pressures and input powers. A distinct transition from the bright mode (primarily inductively coupled) to a dim mode (primarily capacitively coupled) was observed as the pressure was increased and/or the power decreased. The data was further analyzed to estimate the electron temperature, rotational and vibrational temperatures, and various species concentrations. Based on the diffusion and rovibrational relaxation times, it is concluded that the rotational temperatures can be assumed to be in equilibrium with the translational temperature. The ions are produced ``hot'' and have little time to get equilibrated with the translational temperature. It is further determined that in the bright mode, which is more effective in microbe sterilization, the translational/rotational temperatures are in the 650-850 K range, the electron temperatures are low (3.5-4.5 eV), and the concentrations of atomic O and atomic metastables are at 1 order of magnitude higher than in the dim mode.

Biotechnology Progress, 2003

The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were asses... more The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, and biochemical techniques. In low power O 2 plasma (∼25 W, ∼45 mTorr, 90 min), D. radiodurans, a radiation-resistant bacterium, showed a 99.999% reduction in bioburden. In higher power O 2 plasma (100 W and 500 mTorr), the reduction rate increased about 10-fold and observation by atomic force microscopy showed significant damage to the cell. Damage to cellular lipids, proteins, and chromosome was indicated by losses of infrared spectroscopic peaks at 2930, 1651, 1538, and 1245 cm-1 , respectively. In vitro experiments show that O 2 plasmas induce DNA strand scissions and cross-linking as well as reduction of enzyme activity. The observed degradation and removal of biomolecules was power-dependent. Exposures to 200 W at 500 mTorr removed biomolecules to below detection limits in 60 s. Emission spectroscopy indicated that D. radiodurans cells were volatilized into CO 2 , CO, N 2 , and H 2 O, confirming that these plasmas were removing complex biological matter from surfaces. A CO 2 plasma was not as effective as the O 2 plasma, indicating the importance of plasma composition and the dominant role of chemical degradation. Together, these findings have implications for NASA planetary protection schemes and for the contamination of Mars.

AIAA Journal, 2004

An oxygen plasma sustained at 13.56 MHz in a standardized reactor with a planar induction coil wa... more An oxygen plasma sustained at 13.56 MHz in a standardized reactor with a planar induction coil was used for biological decontamination experiments. Optical emission, mass spectrometry, Langmuir probe, and electrical measurements were applied to detection of chemical species and ion-energy and ux analysis. These diagnostics identi ed a plasma-mode transition in the range of 13-67-Pa pressure and 100-330-W power to the induction coil. At higher pressure and lower power, the plasma was sustained in a dim mode (primarily by stray capacitive coupling). A primarily inductive bright mode was attained at lower pressure and higher power. The coupling mode of plasma operation was then monitored by emission spectroscopy on an analogous, scaled-down reactor for biological degradation tests. Plasmid DNA degradation ef cacies were compared in both plasma modes. DNA removal was »25% more ef cient in the inductively coupled mode than in the capacitively coupled mode at the same power. The fast degradation was attributed to synergetic mechanisms (photoand ion-assisted etching by oxygen atoms and perhaps O ¤ 2 metastable molecules). Volatilization rates of the decomposition products (CO 2 , CO, N 2 , OH, H) evolving from the microbial (Deinococcus radiodurans) and polypeptide samples exposed to the plasma were compared. A plasma sustained in Martian atmosphere is considered.

SPIE Proceedings, 2004

A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing h... more A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N 2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N 2 emission at the (0,0) transition of the C 3 Π u-B 3 Π g system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N 2 *) that varied depending on conditions. A twodimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro-and nano-fabrication plasma processing, thus enabling the diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable tracking the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.

Imaging and Applied Optics Technical Papers, 2012

Abstract Laser ablation offers rapid micro-analysis with spatial resolution~ 10 nm in depth,~ 3 μ... more Abstract Laser ablation offers rapid micro-analysis with spatial resolution~ 10 nm in depth,~ 3 μm lateral. Structured materials are mapped, depth-profiled for elemental and isotopic composition using LIBS or LA-ICP-MS without dissolving samples. Molecular structure can be inferred by chemometric processing.

Laser-Induced Breakdown Spectroscopy, 2020

Abstract This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of intere... more Abstract This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of interest are applications in diverse fields that include plasma diagnostics, combustion diagnostics, molecular plasma spectroscopy, and selected astrophysics spectra analyses. Laser ablation molecular isotopic spectrometry (LAMIS) reveals favorable measurement opportunities for identification of atomic isotope compared to direct isotope spectroscopy. For selected molecules of different atomic isotope composition, or for isotopologues, the presented summary discusses LAMIS advantages. LIBS experiments convey formation of diatomic molecules primarily due to recombination. The analysis of diatomic emission spectra reveals excitation temperatures up to 10 kK following laser-induced optical breakdown. Cyanide (CN), aluminum monoxide (AlO), titanium monoxide, Swan bands of C2, and hydroxyl molecules are frequently recorded in nanosecond LIBS investigations over and above the usual atomic emission spectra. The CN molecule occurs within the first few hundred nanoseconds after optical breakdown, and Abel inversion of CN line-of-sight data determines the spatial distributions of molecular signals. For nanosecond LIBS, expansion dynamics and shockwave phenomena explain the measured radial distributions for CN and also for hydrogen. Chemical equilibrium distribution computations assess deviation from thermodynamic equilibrium. This chapter also communicates measurements of AlO ablation spectra and associated analysis with line strength data. Analysis of astrophysics C2 Swan spectra provides further challenges, but in turn can serve as a gauge for chemical analysis with molecular LIBS.

Journal of Analytical Atomic Spectrometry, 2017

This is the original research on the significant intensity enhancement in atomic and molecular em... more This is the original research on the significant intensity enhancement in atomic and molecular emission in laser ablation plasma reheated by an electric pulse.

Physics World, Apr 1, 2013

"Bolshakov and co-workers have developed a technique called LAMIS - laser ablati... more "Bolshakov and co-workers have developed a technique called LAMIS - laser ablation molecul a r isotopic spectrometry that would extend the capabilities of one of Curiosity's existing instruments, ChemCam, to perform optical isotopic analysis."

Spectrochimica Acta Part B: Atomic Spectroscopy, 2016

In this study laser induced breakdown spectroscopy (LIBS) is used for elemental characterization ... more In this study laser induced breakdown spectroscopy (LIBS) is used for elemental characterization of outcrop samples from the Marcellus Shale. Powdered samples were pressed to form pellets and used for LIBS analysis. Partial least squares regression (PLS-R) and univariate calibration curves were used for quantification of analytes. The matrix effect is substantially reduced using the partial least squares calibration method. Predicted results with LIBS are compared to ICP-OES results for Si, Al, Ti, Mg, and Ca. As for C, its results are compared to those obtained by a carbon analyzer. Relative errors of the LIBS measurements are in the range of 1.7 to 12.6%. The limits of detection (LOD) obtained for Si, Al, Ti, Mg and Ca are 60.9, 33.0, 15.6, 4.2 and 0.03 ppm, respectively. An LOD of 0.4wt% was obtained for carbon. This study shows that the LIBS method can provide a rapid analysis of shale samples and can potentially benefit depleted gas shale carbon storage research.

The objective of a virtual impactor is to separate out the larger particles in a flow from the sm... more The objective of a virtual impactor is to separate out the larger particles in a flow from the smaller particles in such a way that both sizes of particles are available for sampling. A jet of particle-laden air is accelerated toward a collection probe so that a small gap exists between the acceleration nozzle and the probe. A vacuum is applied to deflect a major portion of the airstream away form the collection probe. Particles larger than a certain size have sufficient momentum so that they cross the deflected streamlines and enter the collection probe, whereas smaller particles follow the deflected streamlines. The result is that the collection probe will contain a higher concentration of larger particles than is in the initial airstream. Typically, virtual impactors are high-flow devices used to separate out particles greater than several microns in diameter. We have developed a special virtual impactor to concentrate aerosol particles of diameters between 0.5 to 1 micron for th...

Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVII, 2012

ABSTRACT Laser induced plasma can be used for rapid optical diagnostics of electronic, optical, e... more ABSTRACT Laser induced plasma can be used for rapid optical diagnostics of electronic, optical, electro-optical, electromechanical and other structures. Plasma monitoring and diagnostics can be realized during laser processing in real time by means of measuring optical emission that originates from the pulsed laser-material interaction. In post-process applications, eg, quality assurance and quality control, surface raster scanning and depth profiling can be realized with high spatial resolution (~ 10 nm in depth and~ 3 µm lateral). ...

Sensors and Systems for Space Applications V, 2012

abstract A concept of a compact device for analyzing key isotopic composition in surface material... more abstract A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a ...

Spectrochimica Acta Part B: Atomic Spectroscopy, 1997

Inductively coupled plasma (ICP) discharges in chlorine, argon, and their mixtures sustained insi... more Inductively coupled plasma (ICP) discharges in chlorine, argon, and their mixtures sustained inside a spherical quartz container at atmospheric pressure have been investigated. Continua of radiative attachment of a free electron to a chlorine atom in ICP are elucidated and are utilized to derive a spatial profile of electron temperature. A qualitative picture of elementary processes in enclosed ICP is given. Differences between electron and gas temperatures are discussed. Electron temperature is maximum in a periphery layer near the induction coil that is chosen for impurity determination. Concentrations of carbon and metal impurities are estimated.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2011

Russian Chemical Reviews, 2006

The trends in the development of five main branches of The trends in the development of five main... more The trends in the development of five main branches of The trends in the development of five main branches of atomic spectrometry, atomic spectrometry, viz viz., absorption, emission, mass, fluores-., absorption, emission, mass, fluorescence and ionisation spectrometry, are analysed. The advantages cence and ionisation spectrometry, are analysed. The advantages and drawbacks of various techniques in atomic spectrometry are and drawbacks of various techniques in atomic spectrometry are considered. Emphasised are the applications of analytical plasma-considered. Emphasised are the applications of analytical plasmaand laser-based methods. The problems and prospects in the and laser-based methods. The problems and prospects in the development in respective fields of analytical instrumentation development in respective fields of analytical instrumentation are discussed. The bibliography includes 279 references are discussed. The bibliography includes 279 references. .

Journal of Analytical Atomic Spectrometry, 2011

An overview of laser plasma spectrochemistry is presented to demonstrate its wide range of capabi... more An overview of laser plasma spectrochemistry is presented to demonstrate its wide range of capabilities. Laser plasmas offer the ability to perform elemental, isotopic, molecular, quantitative and qualitative sample analysis with sub-micron spatial resolution, and each feature can be measured at standoff distances. Obviously, these attributes are not all achievable at the same time, but they can be optimized for specific applications. This manuscript gives a sampling (pun intended) of the research in our group that has ...

NASA Tech Briefs; www.techbriefs.com/component/content/article/15174, Nov 1, 2012

ABSTRACT A new elegant technology was born and branded as Laser Ablation Molecular Isotopic Spect... more ABSTRACT A new elegant technology was born and branded as Laser Ablation Molecular Isotopic Spectrometry (LAMIS). LAMIS shares all the same technical benefits of its predecessor Laser Induced Breakdown Spectroscopy (LIBS), including rapid analysis and the elimination of sample preparation. LIBS measures atomic emission spectra during the first microsecond after an ablation pulse. LAMIS measurement follows later when the plasma cools down. Then molecules form in the plasma and the intensity of molecular spectra increases and persists for some while. Molecular spectra are useful for isotopic analysis because the isotopic shifts in molecular emission are significantly larger than in atomic spectra. There is no need for a large high-resolution spectrometer; a compact spectrometer can resolve isotopic spectra. LIBS and LAMIS techniques can be accomplished on the same instrument, thus extending ChemCam with a new dimension of isotopic analysis. ChemCam is a scientific instruments on board of the automatic Mars Science Laboratory rover “Curiosity.”

One of the most pressing applications for LIBS is the detection of toxic metals in various matric... more One of the most pressing applications for LIBS is the detection of toxic metals in various matrices. For example, sensitive and rapid determination of lead remains a substantial challenge for other techniques. X-ray fluorescence (XRF) has often been the method of choice because this technique requires no lengthy sample preparation. However, XRF analysis can take 1 to~ 10 min per sample in order to accumulate a detectable signal from low-parts-per-million concentrations of lead. And it can fail to detect even higher ...

Laser-Induced Breakdown Spectroscopy, 2020

This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of interest are ap... more This chapter focuses on molecular laser-induced breakdown spectroscopy (LIBS). Of interest are applications in diverse fields that include plasma diagnostics, combustion diagnostics, molecular plasma spectroscopy, and selected astrophysics spectra analyses. Laser ablation molecular isotopic spectrometry (LAMIS) reveals favorable measurement opportunities for identification of atomic isotope than that for direct isotope spectroscopy. For selected molecules of different atomic isotope composition, or for isotopologues, the presented summary discusses LAMIS advantages. LIBS experiments convey formation of diatomic molecules primarily due to recombination. The analysis of diatomic emission spectra reveals excitation temperatures up to 10 kK following laser induced optical breakdown. Cyanide (CN), aluminum monoxide (AlO), titanium monoxide (TiO), Swan bands of C2, and hydroxyl (OH) molecules are frequently recorded in nano-second LIBS investigations over and above usual atomic emission spectra. The CN molecule occurs within the first few hundred nanosecond after optical breakdown, and Abel inversion of CN line-of-sight data determines the spatial distributions of molecular signals. For nano-second LIBS, expansion dynamics and shock-wave phenomena explain the measured radial distributions for CN and also for hydrogen. Chemical equilibrium distribution computations assess deviation from thermodynamic equilibrium. This chapter also communicates measurements of AlO ablation spectra and associated analysis with line-strength data. Analysis of astrophysics C2 Swan spectra provide further challenges, but in turn, can serve as a gauge for chemical analysis with molecular LIBS.