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

4.1.2 Lower Chamber
The lower chamber consists of two parts: a pumping region and a glass cell, where
the experiments take place. The glass cell (Hellma Cells Inc.) has outer dimensions
30 mm×30 mm×115 mm. The walls are 5 mm thick and consist of Spectrosil, a UV-
grade synthetic fused silica. The walls are optically contacted and fused. A picture of
the glass cell is shown in figure 4.2.
Figure 4.2: Science chamber glass cell.
A vacuum seal between the cylindrical piece of the science chamber glass cell
and the stainless steel chamber is created using a Helicoflex seal (Garlock-Helicoflex
H-307330 REV NC). This seal is shown in figure 4.3. The narrow ridges along the top
and bottom of the seal concentrate the compression load. The metal jacket surrounds a
helical spring. This spring deforms during compression creating the vacuum seal.
The pumping region of the lower chamber is a modified six-way cross with 4-1/2
and 2-3/4 CF flanges. A continously run 75 l/s ion pump (Varian 919-0103), and a
titanium sublimation pump are attached to this chamber. In addition to the pumps, a
nude Bayard-Alpert type ion gauge and an all-metal valve, used for initial pump-out of
the vacuum chamber, are attached to the pumping region. Several blank flanges seal
the remaining ports.
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