Cesium fountain development at USNO

In this paper we discuss progress made at the U.S. Naval Observatory (USNO) towards building a cesium fountain atomic clock. In particular we will address the efficacy of a 4-beam optical lattice as an atom collection and launch mechanism. To date we have measured temperatures in a 4-beam lattice of 1.4(0.3) μK and have launched atoms from this lattice to a height of just under a meter with a temperature of 1.7(0.1) μK. We are able to collect 2.4×10⁶ atoms using only the lattice beams and no magnetic fields. We have completed the design for and are in the process of fabricating all aspects of the fountain device including the collection region, the drift region, the microwave cavity and the magnetic shields. We present our progress to date including a discussion of our launch results and the design and testing of our magnetic shields