Mass-Spectrometric Studies of a Sealed CO2 Laser

Abstract

Short‐term phenomena taking place in a sealed CO₂ laser have been treated mass spectrometrically. Their influences upon laser action and life have been examined in detail. Gas heating is observed to be proportional to the input power and in a water‐cooled laser at 250 W input power is ΔT/T=0.24, resulting in the power decrease by the factor 0.72 at the relaxation time of the order of milliseconds. Decomposition of CO₂ molecules is found to obey the equation CO₂⇌CO+½O₂ which is always at the equilibrium determined by the discharge parameters. The fraction of decomposed molecules is 60% for dc 10 mA and increases slightly with increasing current. The decrease of oxygen during the discharge is the cause of the long‐term shift of equilibrium, which can be suppressed considerably by initial CO filling. These results have been interpreted in terms of the microscopic theory of chemical physics. The proper features in the decomposition mechanism by the discharge have also been given special considerations.