Gas outgassing and mitigation in hemispherical resonator gyroscope for high vacuum maintenance

The outgassing characteristics of adhesives and the sorption characteristics of getters inside the hemispherical resonator gyroscope (HRG) were investigated. For this purpose, four types of adhesives required for the assembly of the HRG were each prepared in a separate glass chamber. The outgassing components and rates of the adhesives were evaluated using a quadrupole mass spectrometer and a real-time vacuum pressure monitoring system, respectively. In addition, the pumping speeds and sorption capacities for H₂ and CO of three types of getters potentially employed in the HRG were tested via the constant-pressure method. Consequently, by integrating the adhesive with the lowest outgassing rate and the getter with the most comparative advantage, a vacuum maintenance experiment within a cavity of equal volume to the HRG demonstrated sustained pressure levels less than 10⁻⁴ Pa over 2500 h. The investigation illustrated in this paper presents a practical strategy for prolonging high vacuum conditions in HRGs and yields a novel scheme for the long-term high vacuum maintenance in the HRG microcavity.