Kr-based buffer gas for Rb vapor-cell clocks

Optically pumped Rb vapor cell clocks are by far the most used devices for timekeeping in all ground and space applications. The compactness and the robustness of this technology make Rb clocks extremely well fit to a large number of applications including GNSS, telecommunication and network synchronization. Many efforts are devoted to improve the stability of Rb clocks and reduce their environmental sensitivity. In this paper, we investigate the use of a novel mixture of buffer gas based on Kr and N₂, capable of reducing by more than one order of magnitude the barometric and temperature sensitivities of the clock, with possible improvement of their long-term stability.