Study on residual gas composition in 316L stainless steel-quartz glass hybrid ultra-high vacuum sealed tube

In this paper, a molecular pump unit was used to prepare a 316L stainless steel-quartz glass hybrid vacuum sealed tube with a background vacuum of 5×10⁻⁷ Pa. Based on a quadrupole mass spectrometer, we analyzed the vacuum preparation process and the residual gas dynamic composition and content when the background vacuum limit was reached. The ultimate vacuum of the sealed tube without high-temperature baking was about 5×10⁻⁵ Pa, and H₂O was the residual gas with the highest partial pressure ratio. By further continuous high-temperature baking, it was possible to increase the ultimate vacuum to 3.7×10⁻⁷ Pa. At this time, the main residual gas components were H₂, H₂O, CH₄, CO₂, CO in a descending order, which was mainly released from the inner surface of the sealed tube, as well as gas attached to the filament of the mass spectrometer. The use of ion pump, sublimation pump and getter pump could further improve the background vacuum.