2002年4月
Laser-induced fluorescence instrument for the detection of tropospheric OH radicals
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
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- 巻
- 75
- 号
- 4
- 開始ページ
- 711
- 終了ページ
- 717
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1246/bcsj.75.711
- 出版者・発行元
- CHEMICAL SOC JAPAN
An instrument for the measurement of troposphric OH radical concentrations using a laser-induced fluorescence technique has been developed. Ambient air is expanded through a pinhole into a low-pressure fluorescence cell and irradiated by the second harmonic of a dye laser at a high repetition rate of 1 kHz. The OH radicals are electronically excited using A(2) Sigma(+) (v' = 0) <-- X-2 Pi (v" = 0) transitions around 308 nm. The fluorescence from OH radicals is collected by a lens system and detected by a photomultiplier. The photoelectron pulses from the photomultiplier are processed by a photon-counting system. The dynode gate of the photomultiplier and counting gate systems are made to minimize the detection of the chamber and Rayleigh scattering signal. The sensitivity of the developed instrument is calibrated with two methods: one is a long-path absorption technique and the other is a titration technique with simultaneous photolysis of water vapor and oxygen. It is found that the background signal is mainly produced by after-pulse effects in the photomultiplier for the fluorescence detection with a dynode gate system. The minimum detection limit is determined to be 7.0 X 10(5) Molecules cm(-3) for OH radicals with a signal-to-noise ratio of 2 and a signal integration time of 60 s.
- リンク情報
- ID情報
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- DOI : 10.1246/bcsj.75.711
- ISSN : 0009-2673
- eISSN : 1348-0634
- J-Global ID : 200902133970112539
- Web of Science ID : WOS:000175354600009