Purge-free open-path system and method for cavity enhanced spectroscopy

Abstract

A method of measuring a quantity or characteristic of a qualified air, e.g., clean air or prefiltered air, present in an environment, e.g., a chamber or a cleanroom, includes freely placing a measurement apparatus with an open multipass cell in the environment, and allowing a qualified air, such as clean air or prefiltered air, present in the environment to move freely into and out of an optical cavity of the open multipass cell. The method further includes obtaining a measurement of a quantity or a characteristic based on the qualified air in the optical cavity.

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