A Portable Cold 87Rb Atomic Clock with Frequency Instability at One Day in the 10−15Range

Abstract

We present a small portable cold8 7Rubidium atomic clock with frequency uncertainty of less than $3\times 10^{-15}$ in one day of averaging time. The clock is under development at SpectraDynamics for the Defense Advanced Research Projects Agency (DARPA) Portable Microwave Cold Atomic Clock Small Business Innovation Research (SBIR) effort. The portable clock is about the size of a desktop computer (22×37×32 cm) and weighs 28kg.