Details

Autor(en) / Beteiligte

• De Vries, H.S.M.
• Harren, F.J.M.
• Wyers, G.P.
• Otjes, R.P.
• Slanina, J.
• Reuss, J.

Titel

Non-intrusive, fast and sensitive ammonia detection by laser photothermal deflection

Ist Teil von

• Atmospheric environment (1994), 1995, Vol.29 (10), p.1069-1074

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

1995

Quelle

ScienceDirect

Beschreibungen/Notizen

• A recently developed non-intrusive photothermal deflection (PTD) instrument allows sensitive, rapid and quantitative detection of local ammonia concentrations in the air. Ammonia is vibrationally excited by an infrared CO 2 laser in an intracavity configuration. A HeNe beam passing over the CO 2 laser beam (multipass arrangement) is deflected by the induced refractive index gradient. The detection limit for ammonia in ambient air is 0.5 ppbv with a spatial resolution of a few mm 3. The time resolution is 0.1 s (single line) or 15 s (multi line). The system is fully automated and suited for non-stop measuring periods of at least one week. Results were compared to those obtained with a continuous-flow denuder (CFD).