GLACE: a technology demonstration experiment for laser cooled atomic clocks in space

Summary form only given. The long observation times afforded by laser cooling of neutral atoms ushered in a new era of accuracy and stability for cesium atomic clocks. Traditional thermal beam atomic clocks are limited to interaction times of only a few milliseconds, while with laser cooling times of order 1 second have been realized with high stability. Most laser cooled clocks use a "fountain" geometry, in which the atoms are thrown up against the pull of gravity and realize longer times before falling back to the bottom of the apparatus. We have been developing a laser-cooling apparatus for flight on the International Space Station (ISS), with the intention of demonstrating linewidths of the cesium clock transition narrower than can be realized on the ground.