Ticking toward an advanced atomic clock
Ticking toward an advanced atomic clock lead image
Because atomic clocks do not need to sync with other clocks to maintain accuracy, they are crucial to applications such as global navigation satellite systems and telecommunications. Recent research and development efforts have produced prototypes of miniature microwave ion clocks, a relatively new form of atomic clock technology that measures time with ground state energy level splitting of buffer gas-cooled mercury or ytterbium (Yb) ions confined in radio frequency (RF) traps.
Thrasher and Schwindt demonstrated the decadal shelf-life of miniature vacuum chambers used to store Yb ions and the potential use of these vacuum chambers for highly precise yet compact (3 cm3) microwave atomic clocks.
“Commercial miniature atomic clocks currently rely on vapor cell technology to store ensembles of atoms due to the compactness and longevity of the vapor cells,” said author Daniel Thrasher. “The passive vacuum chambers in this study are of similar size to vapor cells yet demonstrate less clock instability.”
The researchers characterized two vacuum chambers, each containing an RF ion trap, enriched ytterbium metal, and buffer gas, which were fabricated by NASA’s Jet Propulsion Laboratory. One had been sealed with helium buffer gas in 2012, the other with neon buffer gas in 2018.
“The long shelf-life demonstrated in our study means that clocks made from these vacuum chambers should remain functional for decades,” said Thrasher. “Such reliability is important for keeping time in critical infrastructure where clock failure would lead to unacceptable consequences, and in hard-to-reach places like outer space, where the immense effort required to install the clock mandates that it function for many years.”
Source: “Performance of 3 cm3 ion trap vacuum package sealed for 10 years,” by D. A. Thrasher and P. D. D. Schwindt, Applied Physics Letters (2025). The article can be accessed at https://doi.org/10.1063/5.0243517 .
