Experimental and computational investigation into the hydrodynamics and chemical dynamics of laser ablation aluminum plasmas

Kwapis, Emily H.; Posey, Jacob; Médici, Ezequiel; Berg, Kathleen M.; Houim, Ryan W.; Hartig, Kyle C.

doi:10.1039/d3cp01586f

Cited by 6 publications

(14 citation statements)

References 76 publications

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“…This increasing thickness of the boundary layer over time is correlated with decreasing temperature gradients as the plasma plume expands and cools. 133 Kwapis et al 138 present multi-physics simulations on the multi-phase thermochemistry and hydrodynamics of Al plumes, demonstrating that fluid dynamics and vortex formation work to further encourage intermixing between reacting species in addition to diffusion processes (Figure 4). Gas-phase Al is shown to become predominantly distributed in the vortices of the plume for times ≥5 µs, while oxygen and Al x O y species are pulled up through the stem to encourage molecular formation in the head of the plume.…”

Section: Laser Ablation Plasma Chemistrymentioning

confidence: 99%

“…Gas-phase Al is shown to become predominantly distributed in the vortices of the plume for times ≥5 µs, while oxygen and Al x O y species are pulled up through the stem to encourage molecular formation in the head of the plume. 138 Beyond the spatial characteristics and thermal properties of the plasma plume, chemical reactions also depend on the bond strengths of the molecules themselves. Molecules with lower dissociation energies (3 eV> D 0 > 6 eV) preferably form in the cooler periphery of the plasma plume, while molecules characterized by higher dissociation energies (D 0 > 6 eV) form nearer to the plasma core where temperatures are higher.…”

Section: Laser Ablation Plasma Chemistrymentioning

confidence: 99%

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Laser Ablation Plasmas and Spectroscopy for Nuclear Applications

Kwapis,

Borrero,

Latty

et al. 2023

Appl Spectrosc

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The development of measurement methodologies to detect and monitor nuclear-relevant materials remains a consistent and significant interest across the nuclear energy, nonproliferation, safeguards, and forensics communities. Optical spectroscopy of laser-produced plasmas is becoming an increasingly popular diagnostic technique to measure radiological and nuclear materials in the field without sample preparation, where current capabilities encompass the standoff, isotopically resolved and phase-identifiable (e.g., UO and UO[Formula: see text]) detection of elements across the periodic table. These methods rely on the process of laser ablation (LA), where a high-powered pulsed laser is used to excite a sample (solid, liquid, or gas) into a luminous microplasma that rapidly undergoes de-excitation through the emission of electromagnetic radiation, which serves as a spectroscopic fingerprint for that sample. This review focuses on LA plasmas and spectroscopy for nuclear applications, covering topics from the wide-area environmental sampling and atmospheric sensing of radionuclides to recent implementations of multivariate machine learning methods that work to enable the real-time analysis of spectrochemical measurements with an emphasis on fundamental research and development activities over the past two decades. Background on the physical breakdown mechanisms and interactions of matter with nanosecond and ultrafast laser pulses that lead to the generation of laser-produced microplasmas is provided, followed by a description of the transient spatiotemporal plasma conditions that control the behavior of spectroscopic signatures recorded by analytical methods in atomic and molecular spectroscopy. High-temperature chemical and thermodynamic processes governing reactive LA plasmas are also examined alongside investigations into the condensation pathways of the plasma, which are believed to serve as chemical surrogates for fallout particles formed in nuclear fireballs. Laser-supported absorption waves and laser-induced shockwaves that accompany LA plasmas are also discussed, which could provide insights into atmospheric ionization phenomena from strong shocks following nuclear detonations. Furthermore, the standoff detection of trace radioactive aerosols and fission gases is reviewed in the context of monitoring atmospheric radiation plumes and off-gas streams of molten salt reactors. Finally, concluding remarks will present future outlooks on the role of LA plasma spectroscopy in the nuclear community.

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Section: Laser Ablation Plasma Chemistrymentioning

confidence: 99%

Section: Laser Ablation Plasma Chemistrymentioning

confidence: 99%

Laser Ablation Plasmas and Spectroscopy for Nuclear Applications

Kwapis,

Borrero,

Latty

et al. 2023

Appl Spectrosc

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“…Simple monoxides yield higher gas-phase polyatomic oxides that ultimately condense into nanoparticles that agglomerate into larger nanoclusters as the plasma cools. 9,10 Molecular information characterizing the sample material is key to understanding the composition of organics, oxidation, crystallinity, calcination, carbon content, precursor, etc. in that material.…”

Section: Introductionmentioning

confidence: 99%

“…Simple monoxides yield higher gas-phase polyatomic oxides that ultimately condense into nanoparticles that agglomerate into larger nanoclusters as the plasma cools. 9,10…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Plasmas of Plutonium Dioxide in a Double-Walled Cell

Villa-Aleman,

Kwapis,

Foley

et al. 2024

Appl Spectrosc

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Plutonium research has been stifled by the significant number of administrative controls and safety procedures, space and instrumentation limitations in radiological gloveboxes, and the potential for personnel and equipment contamination. To address the limited number of spectroscopic studies in Pu-bearing compounds in the current scientific literature, this work presents the use of double-walled cells (DWCs) in “clean” buildings/laboratories as an alternative to research in radiological gloveboxes. This study reports the first laser-induced breakdown spectroscopy (LIBS) experiments of a PuO2 pellet contained within a DWC, where the formation of elemental (atomic and ionic) species as well as the evolution from elemental to molecular products (Pu xO y) was measured. Raman spectroscopy was also used to characterize the surface of the ablated pellet and the particulates deposited on the window of the inner cell. The full width half-maximum of the T2g band enabled us to obtain an estimate of the temperature at the pellet surface after the ablation pulse and the particulates based on the crystal lattice disorder. Particulates deposited on the window of the DWC during laser ablation were characterized using scanning electron microscopy, where molten irregular particulates and spheroids were observed. This exciting research conducted in a DWC describes our initial attempts to incorporate LIBS in the arsenal of spectroscopic tools for nuclear forensics applications.

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“…This approach has been applied to demonstrate that monoxides such as AlO and SrO first form in the cooler periphery of the plasma plume, while other species such as ZrO and UO are more centrally located within the plasma core. 31–34 The spatial distribution of chemical species within laser ablation plasmas is believed to be driven by plasma-gas intermixing processes as well as properties of the molecules themselves, where molecules characterized by higher dissociation energies are able to form in the presence of hotter temperature conditions. 32,35,36…”

Section: Introductionmentioning

confidence: 99%