Experiments to Control Atom Number and Phase-Space Density in ...

Chapter 7
Lithium Apparatus
Creating Fock states of lithium atoms requires a complex series of experimental
steps, and many different sub-systems of the experimental apparatus have to work to-
gether. Even though great effort was made to keep the experimental setup as simple as
possible, a large number of different devices are required. This chapter summarizes the
design and construction of the experimental apparatus and details the methods employed
for detection of the atomic ensemble.
7.1 Vacuum Chamber
Three main requirements determine the design of the vacuum chamber: the de-
sired vacuum pressure, sufficient optical access, and ease of building and assembly. Col-
lisions between the atoms of interest and background gas atoms are detrimental to the
creation of Fock states of atoms. Therefore, vacuum pressures in the low 10 −10 Torr
range or better are necessary. Optical access is required for cooling and trapping the
atoms, creating the optical dipole traps for evaporative cooling and laser culling, and
for detection of the atoms.
The design of our vacuum chamber consists of two main parts: the oven chamber
and the science chamber. They are connected through a differential pumping tube which
also serves as the Zeeman slower. A complete drawing of the vacuum chamber is shown
in figure 7.1. With the experience gained from previous cold atom experiments, the
vacuum chamber is designed to rely almost exclusively on passive alignment. This,
however, places tight requirements on the dimensions for machining of the parts. Most
particularly, the parallelism of opposing flanges has to be precisely controlled to ensure
a straight beam path for the effusive lithium beam.
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