Thursday 10
M. Measurement Techniques
Chair: A. Haddad - Each talk is 10'+2' duration
› 15:10 - 15:20 (10min)
› Cabannes
Determination of absolute atomic hydrogen densities by Two-Photon Absorption Laser Induced Fluorescence in a H2/CH4 Microwave Plasma at High Pressure and High Microwave Power
Maxime Wartel  1@  , Corinne Duluard  2, *@  , Xavier Aubert  2@  , Cathy Rond  2@  , Alix Gicquel  2@  
1 : Groupe de recherches sur l'énergétique des milieux ionisés  (GREMI)  -  Website
CNRS : UMR7344, Université d'Orléans
14 Rue d'Issoudun - BP 6744 45067 ORLEANS CEDEX 2 -  France
2 : Laboratoire des Sciences des Procédés et des Matériaux  (LSPM)  -  Website
CNRS : UPR3407
Université Paris 13, Campus de Villetaneuse, 99 avenue Jean-baptiste Clément, 93430 Villetaneuse -  France
* : Corresponding author

In the context of monocrystalline diamond plasma deposition, the atomic hydrogen densities have been determined by two-photon absorption laser induced fluorescence in a H2/CH4 microwave plasma at high pressure (200 hPa) and high microwave power (3000 W). H-atom densities were estimated by a calibration method that consists in normalizing the H-atom TALIF intensity by the intensity from Kr atoms in a pure krypton gas at a known pressure. In the range of pressures studied, the value of the H-atom fluorescence yield, which is necessary for the calculation of absolute densities, cannot be determined experimentally, but is estimated from a model calculation that solves the rate equations describing the population changes in the various H n=3 sublevels. In plasmas containing 1% CH4, the H-atom densities reach values ≥ 1.9×1023 m-3, and the gas temperature in the plasma bulk is ~3000 K.


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