Ground-State Atomic Nitrogen Measurements using fs-TALIF in High-Pressure NRP Discharges
Résumé
Measurements of ground state atomic nitrogen inside of a nanosecond repetitively pulsed (NRP) discharge operating at pressures between 0.1-5 bar are performed using a femtosecond two-photon absorption laser induced fluorescence (fs-TALIF) technique. The main goal of this work is to develop a quench-free diagnostic technique which would allow measurements at elevated pressures with high spatial and temporal resolution. Quantitative information is extracted from the TALIF signal via a novel calibration technique based on direct absorption measurements performed in a low-pressure DC discharge. The VUV measurements were done at the Soleil synchrotron facility using their unique high-resolution Fourier-transform spectrometer (⁄ =). During this preliminary work, fs-TALIF measurements of N(4 S) are demonstrated in the post-discharge of the NRP between 1-500 µs after the nanosecond pulse. A maximum number density of N-atoms of × was measured at 1 µs after the pulse when the discharge was operated at 1 bar in pure nitrogen. Importantly, the limit of detection of the fs-TALIF technique was determined to be ()~. This is approximately two orders of magnitude lower than previously reported by ns-TALIF.
Domaines
PlasmasOrigine | Fichiers produits par l'(les) auteur(s) |
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