Investigation of the intrinsic outgassing rates for narrow structured vacuum devices under readsorption effect

Abstract

The narrow structure within the vacuum system usually results in a slow evacuation process. Additionally, the high outgassing rate caused by the large surface-to-volume ratio can prevent the vacuum level from meeting the performance requirements of the device. In this paper, the evacuation of the stainless steel parallel plates is established based on a two-dimensional equation combined with the outgassing theory of the recombination–dissociation-limited model. The relationship between the measured and intrinsic outgassing rates was investigated by varying the gap size, pump-out port size, and temperature. The results show that the internal pressure is nonuniformly distributed during the pump-down process, even reaching a quasiequilibrium state. This indicates that the widely used throughput method can make a difference in measuring outgassing rates. This provides a theoretical basis for testing intrinsic outgassing rates, calculating pressure distribution, and configuring pumps or getters in complex vacuum systems.