Adventures with trapped ion atomic clocks: from nuclear structure to deep space navigation

The advent of trapping and cooling of atoms and ions has revolutionized atomic clocks. The resulting unprecedented accuracy and stability has enabled many applications as well as fundamental science. At the Jet Propulsion Laboratory (JPL), we have had a long-standing program to develop room-temperature microwave trapped ion atomic clocks, primarily for deep space navigation applications. This work has been divided into three broad areas: 1) ultra-stable clocks that can operate autonomously, 2) space clocks, and 3) miniature clocks. In this talk I will focus onthe first two applications. Over the years various refinements in this technology, including the linear ion trap, the multi-pole trap, and the compensated multi-pole trap, have led to state-of-the-art clock stability. In this talk I will first describe this technology as implemented at JPL and how we were able to achieve its high degree of stability. Next, I will describe how this technology was adapted for operation in space, with the associated constraints on size and robustness and how operation of this technology in space enables a new type of deep space navigation. Finally, I will describe several scientific applications of this technology, including a measurement of the Hyperfine Anomaly in mercury ions, essentially a measure of the size of the nucleus, new ways to place limits on fundamental constant variation, and proposals to test general relativity and to enable radio science measurements used to better understand planetary atmospheres and gravitational fields.