Optical emission spectroscopy and laser scattering for laser induced plasmas diagnostic
Description
Laser induced plasma (LIP) which was first reported in the beginning of sixties, has achieved a great interest as a source of spectroscopic data. It has also many applications like X-ray sources for lithography, plasma igniters, pulsed laser deposition or it has become a basis of a very popular analytical technique - LIBS (laser induced breakdown spectroscopy). The latter is mainly due to its applicability to different kinds of samples, no sample preparation or in-situ and remote sensing capability. However, LIBS measurements are laterally integrated and Abel inversion must be performed. Also the method assumes the plasma to be in local thermodynamic equilibrium (LTE). In order to validate LIBS measurements, Thomson scattering (TS) method which is spatially resolved and free from equilibrium assumption was applied. Thus, ablation and breakdown plasmas were characterized by both two methods. Comparison between plasma parameters (temperature and electron density) obtained by the two methods and McWhirter criterion as well as relaxation times and diffusion lengths of species in the plasma allowed to estimate LTE. (author)
Abstract (French)
Les plasmas induits par laser (PIL) ont depuis leurs apparitions dans les annees soixante suscite un tres grand interet notamment comme source de donnees spectroscopiques. Ils ont egalement acquis des nombreuses applications, comme sources des rayons X pour la lithographie, l'allumage plasma, la deposition par laser pulse, ou sont devenues la base d'une technique d'analyse tres populaire - la LIBS (laser induced breakdown spectroscopy). Cette derniere peut s'appliquer in situe a tout type d'echantillon et sans preparation. Toutefois, les mesures faites par cette methode sont lateralement integrees necessitant des techniques d'inversion, mais dependent egalement des conditions d'equilibre thermodynamiques local (ETL) dans le plasma. Afin de valider les mesures effectuees par LIBS, la diffusion Thomson qui est une methode spatialement resolue et independante des hypotheses d'equilibre thermodynamique a ete appliquee pour caracteriser les PIL. Des plasmas d'ablation et de claquage ont donc ete caracterises a la fois par spectroscopie d'emission et par diffusion Thomson. La comparaison des parametres temperature et densite electronique obtenues par les deux methodes d'une part, et le critere de McWhirter ainsi que les temps de relaxation et les longueurs de diffusions des especes contenues dans le plasma d'autre part, ont permis de statuer sur l'ETL. (auteur)
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Additional details
Additional titles
- Original title (French)
- Spectroscopie optique d'emission et spectroscopie laser pour le diagnostic des plasmas induits par laser
Publishing Information
- Imprint Pagination
- 217 p.
- Report number
- FRNC-TH--10256
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 49101627
- Subject category
- S46: INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; S70: PLASMA PHYSICS AND FUSION TECHNOLOGY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- ALUMINIUM; ARGON; CALIBRATION; CHARGE-COUPLED DEVICES; DOPPLER EFFECT; ELECTRON DENSITY; ELECTRON TEMPERATURE; EMISSION SPECTRA; EMISSION SPECTROSCOPY; LASER SPECTROSCOPY; LASER-RADIATION HEATING; LINE BROADENING; NITROGEN; PLASMA DIAGNOSTICS; PULSES; RELAXATION TIME; SELF-ABSORPTION; SYNCHRONIZATION; THOMSON SCATTERING
- Descriptors DEC
- ABSORPTION; ELEMENTS; FLUIDS; GASES; HEATING; INELASTIC SCATTERING; METALS; NONMETALS; PLASMA HEATING; RARE GASES; SCATTERING; SEMICONDUCTOR DEVICES; SORPTION; SPECTRA; SPECTROSCOPY
Optional Information
- Notes
- 166 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses