Analyzing a gas mixture by generating a photoacoustic signal comprises adding a gas that suppresses kinetic cooling

摘要

Analyzing a gas mixture by exposing it to intensity-modulated electromagnetic radiation in a test zone and detecting radiation-absorbing gases and/or impurities by means of a photoacoustic signal comprises adding to the mixture a gas (G2) that suppresses kinetic cooling so that the photoacoustic signal is an unambiguous measure of the energy absorbed by the radiation-absorbing gases and/or impurities. Independent claims are also included for: (1) suppressing and/or analyzing kinetic cooling in an optical imaging or irradiating system comprising a zone through which electromagnetic radiation is passed and and which is filled or flushed with a radiation-nonabsorbing protective gas (G1), by enriching G1 with a gas (G2) in an amount such that kinetic cooling is suppressed and/or the partial pressure of G2 is 2-300 mbar and/or the energy absorbed by radiation-absorbing gases and/or impurities in G1 is an unambiguous means of assessing the radiation quality of the system and/or the G1+G2 mixture can be analyzed for radiation-absorbing gases and/or impurities; (2) gas analysis system comprising a detection chamber (3) that can be filled with a gas mixture to be analyzed, a radiation source (11) for irradiating the detection chamber with intensity-modulated electromagnetic radiation, and an acoustic sensor (7) for detecting pressure fluctuations produced by the photoacoustic effect, and a device for adding to the mixture a gas (G2) that suppresses kinetic cooling.