2 edition of Theory for laser-induces breakdown over a vaporizing target surface found in the catalog.
Theory for laser-induces breakdown over a vaporizing target surface
Robert J. Harrach
by Dept. of Energy, for sale by the National Technical Information Service in [Washington], Springfield, Va
Written in English
|Statement||Robert J. Harrach.|
|Series||UCRL ; 52389|
|Contributions||United States. Dept. of Energy., Lawrence Livermore Laboratory.|
|The Physical Object|
|Pagination||iii, 23 p. :|
|Number of Pages||23|
In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at. Abstract. The class A-I Preparing the oil by means of evaporation without using auxiliary agents or mechanical means, may be subdivided according to whether evaporation takes place in open devices of atmospheric pressure or in closed vessels under higher pressures. In the first case the gas or vapour evolved is not able to develop any appreciable kinetic energy, whereas in the second case Author: Hendrik A. Romp.
The technique is named Laser Induced Breakdown Spectroscopy (LIBS) and numerous reviews and three recent text books have already been published addressing both general and specific aspects, in the relatively short period after the technique had undergone a renewed interest in the beginnings of the eighties. On the other hand, the. UV lasers are a commonly-used tool for cutting into tissue, but the lasers usually make incisions by vaporizing one point at a time in a series of steps.
Chapter 6 Femtosecond Laser Ablation: Fundamentals and Applications Sivanandan S. Harilal, Justin R. Freeman, Prasoon K. Diwakar and Ahmed Hassanein Abstract Traditionally nanosecond laser pulses have been used for Laser-induced Breakdown Spectroscopy (LIBS) for quantitative and qualitative analysis of the samples. Collective Drop Effects on Vaporizing Liquid Sprays, A Dissertation Presented to the Faculty of Princeton University in Candidacy for the Degree of Doctor of Philosophy [Peter John O'Rourke] on *FREE* shipping on qualifying offers. Collective Drop Effects on Vaporizing Liquid Sprays, A Dissertation Presented to the Faculty of Princeton University in Candidacy for the Degree of.
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A simple but accurate theoretical model is developed to describe the growth of avalanche ionization (breakdown) in the blowoff vapor from a laser-irradiated surface.
This nonequilibrium model is applicable to laser intensities and wavelengths from approximately 10/sup 7/ to 10/sup 12/.m/sup 2. The model pertains only to the early stages of laser-target interaction, from the time surface vaporization begins to when first-degree ionization is achieved in the vapor.
Approximate analytical solutions are found for the basic differential equations of the model, and such key quantities as breakdown time and threshold values of laser fluence and intensity are expressed in terms of simple Cited by: Get this from a library.
Theory for laser-induced breakdown over a vaporizing target surface. [Robert J Harrach; United States. Department of Energy.; Lawrence Livermore Laboratory.]. Laser-induced breakdown thresholds for several pure metals were determined using a nanosecond laser.
A Q-switched pulsed Nd:YAG laser operating at infrared ( nm), visible ( nm) and ultraviolet ( nm) wavelengths has been used. The plasma was generated by focusing the Nd:YAG laser on the target in air at atmospheric by: As a result, obvious vaporization may occur. Fig. 2 shows that when the ps laser pulse fluence is 6 J/cm 2, the sidewall surface vaporization mainly occurs in the region of z = ∼– μm.
The peak vaporization depth occurs at z = ∼ μm, which is slightly below the initial plasma top z Cited by: 2. Wavelength dependence of laser ablation of silicon was investigated with nanosecond ultraviolet, visible, and infrared laser pulses in the irradiance range from 3× to 1× W/cm2.
For and nm laser pulses, the depth of laser-produced crater shows a dramatic increase at a laser irradiance threshold of approximately 2× and 4× W/cm2 respectively, above which, large Cited by: As the laser beam is focused on solid surface, the sample material absorbs the.
laser energy to melt and vaporize a certain amount of material. The vapor absorbs laser. energy and forms a high temperature plasma near the sample by: 1. Laser Induced Breakdown Spectroscopy (LIBS) is an emerging technique for determining elemental composition.
With the ability to analyse solids, liquids and gases with little or no sample preparation, it is more versatile than conventional methods and is ideal for on-site analysis. This is a comprehensive reference explaining the fundamentals of the LIBS phenomenon, its history and its 3/5(1).
a target, thereby vaporizing the material of the surface region. The ejected material is partially 5 Ablation and Thin Film Deposition 93 theory where the surface temperature of the target at the end of the laser pulse is determined by the light absorption and thermal diffusivity.
It is therefore expected. other hand, permanent laser-induced material modifications have found inter- esting applications for laser micro- and nanostructuring as well as for the production of three-dimensional waveguides. The advantages of laser-induced breakdown spectroscopy (LIBS), such as sample preparation not being required and in situ remote analysis, make it an efficient method for the analysis of hazardous samples and samples in remotely accessible or hazardous environments.
The nuclear industry has become one of the fast-growing fields of LIBS application. R.J. Harrach, Theory for laser-induced breakdown over a vaporizing target surface, awrence Livermore laboratory, University of California, report UCRL, Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure elemental composition.
With the development of lasers and detection systems, applications of LIBS encompass a broad range, including physics, engineering, space missions, environment, etc.
due to the unique features of little or no sample preparation, noncontact Cited by: 5. Harrach, “ Theory for laser-induced breakdown over a vaporizing target surface,” Lawrence Livermore Laboratory, University of California Report No.
Cited by: 4. LIBS (laser induced breakdown spectroscopy) is a relatively new version of atomic emission spectroscopy made possible with the invention of the laser. A high-energy laser pulse is focused down to target a gas, liquid, or solid substance creating a dielectric breakdown or “plasma spark”.
This high-temperature atomization provides. Laser-induced breakdown spectroscopy (LIBS) is a technique that provides an accurate in situ quantitative chemical analysis and, thanks to the developments in new spectral processing algorithms in the last decade, has achieved a promising performance as a quantitative chemical analyzer at the atomic level.
These possibilities along with the fact that little or no sample preparation is Cited by: Laser induced optical breakdown (LIOB) is a non-linear absorption process leading to plasma formation at locations where the irradiance threshold for breakdown is surpassed [4–6].
The initiation of breakdown can occur either through multiphoton absorption as in the case of LIOB or through the thermal initiation pathway as in the case of laser induced thermal break down or LITB [ 7, 8 ].Cited by: 8.
The key achievements in the determination of trace amounts of components in environmental samples (soils, ores, natural waters, etc.) by laser-induced breakdown spectrometry are capabilities of this method make it suitable for rapid analysis of metals and alloys, glasses, polymers, objects of cultural heritage, archaeological and various environmental by: Laser-Induced Breakdown Spectroscopy Jagdish P.
Singh, Surya Narayan Thakur Laser induced breakdown spectroscopy (LIBS) is basically an emission spectroscopy technique where atoms and ions are primarily formed in their excited states as a result of interaction between a tightly focused laser beam and the material sample. As stated in our first article, 1 laser-induced breakdown spectroscopy has become a very attractive and popular technique in the field of chemical analysis.
The first proof of this statement is that the LIBS community keeps increasing, as testified by the growing number of participants each year at the conferences dedicated to the various aspects of the technique (see Table I in Ref. 1).Cited by:. This study describes experimental work examining the critical energy for direct initiation of detonation by laser ablation in a stoichiometric acetylene–oxygen mixture.
The amount of input energy, the target material, and the surface roughness of the target were varied to study their effects on shock wave generation. Aluminum and stainless steel were used as target by: 3.In this article, an increase of 1–2 orders of magnitude in laser-induced breakdown spectroscopy (LIBS) signals was obtained by depositing silver nanoparticles on metal samples.
Nanoparticle-enhanced LIBS (NELIBS) was found to be a robust and flexible tool for the chemical analysis of metals because the sample emission signal did not appear to be affected much by the size and concentration of Cited by: Search the history of over billion web pages on the Internet.
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