14 December 2016 Measurement of an ambient air leak by diode laser absorption spectroscopy
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Proceedings Volume 10176, Asia-Pacific Conference on Fundamental Problems of Opto- and Microelectronics; 101760T (2016) https://doi.org/10.1117/12.2268278
Event: Asia-Pacific Conference on Fundamental Problems of Opto- and Microelectronics, 2016, Khabarovsk, Russia
Abstract
Absorption spectroscopy measurements of long-lived metastable argon atoms Ar* in a low-pressure RF-discharge were carried out to measure gas leaks in a vacuum chamber. Argon as a carrier gas was flowing through the test chamber and the discharge cell at a rate of 55 μmol/s. If a leak occurs, the ambient air is admixed to the carrier gas flowing through the test chamber. The presence of air in the carrier gas flowing through the discharge plasma produced a decrease in the number density of Ar*, which was measured by means of diode laser absorption spectroscopy. This is because the lifetime of atoms is limited by losses due to collisions with air molecules. The leak-rate of the ambient air ranged from 0.14 to 0.95 μmol/s was measured by a mass flow meter and compared with the amplitude of the absorption signal.
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Alexander K. Chernyshov, Pavel A. Mikheyev, "Measurement of an ambient air leak by diode laser absorption spectroscopy ", Proc. SPIE 10176, Asia-Pacific Conference on Fundamental Problems of Opto- and Microelectronics, 101760T (14 December 2016); doi: 10.1117/12.2268278; https://doi.org/10.1117/12.2268278
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