Gas contaminants produced in electron-beam-pumped XeF lasers

To achieve extended gas lifetime in electron-beam (e-beam)-pumped XeF lasers requires knowledge of the gas contaminants produced as a result of homogeneous reactions within the gas mixture and heterogeneous reactions with the laser device materials (e.g. walls and foil). The authors present mass-spectrometer measurements of the contaminants created in an e-beam-pumped XeF laser (300-kV, 23-kA e beam with 10 A/cm² at the foil) as a result of multiple shots on the same gas mixture using F₂ as the halogen fuel. The major contaminants detected, listed in order of prominence, are O₂, CO₂, CF₄, CO, and SiF₄. With regard to degradation of the laser performance, it is found that the laser is sensitive to (listed from most sensitive to least) SiF₄, CO, HF, CO₂ , CF₄, and O₂. Tests indicate that the major source of contaminants in this particular device is from the e beam striking the opposing wall of the laser chamber