Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
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an ion gauge controller (Granville Phillips, 350), <strong>and</strong> an angle valve (VAT valve, 54032-<br />
GE02) are connected via this elbow.<br />
The entire oven chamber setup is supported by an 80/20 support structure.<br />
7.1.2 Differential Pump<strong>in</strong>g Tube<br />
The differential pump<strong>in</strong>g tube is located between the oven chamber <strong>and</strong> the<br />
science chamber. There is a small bellows (St<strong>and</strong>ard Bellows Company, 64-34-1-EE) at<br />
the front end, see figure 7.5. This bellows allows for angular adjustment of the oven<br />
chamber relative <strong>to</strong> the science chamber. To achieve maximum differential pump<strong>in</strong>g the<br />
diameter of the open<strong>in</strong>g <strong>in</strong> the tube should be m<strong>in</strong>imized <strong>and</strong> its length maximized.<br />
However, a longer length leads <strong>to</strong> a larger angular spread of the a<strong>to</strong>ms, reduc<strong>in</strong>g the<br />
a<strong>to</strong>mic flux <strong>in</strong> the science chamber. Ultimately the length of the differential pump<strong>in</strong>g<br />
tube is determ<strong>in</strong>ed by the length of the Zeeman slower.<br />
Figure 7.5: The small bellows at the end of the differential pump<strong>in</strong>g tube allows for the<br />
alignment of the a<strong>to</strong>mic beam axis between the oven chamber <strong>and</strong> the science chamber.<br />
To m<strong>in</strong>imize the conductivity between the two parts of our vacuum setup, the<br />
profile <strong>in</strong>side the differential pump<strong>in</strong>g tube matches the expected a<strong>to</strong>mic beam profile.<br />
The <strong>in</strong>itial open<strong>in</strong>g <strong>in</strong> the differential pump<strong>in</strong>g tube is 5 mm <strong>in</strong> diameter <strong>and</strong> it exp<strong>and</strong>s<br />
<strong>to</strong> a f<strong>in</strong>al diameter of 13 mm <strong>in</strong> 9 steps, as shown <strong>in</strong> figure 7.6. These steps approximate<br />
the ideal tapered profile. The groove <strong>in</strong> the back flange <strong>and</strong> the groove at the beg<strong>in</strong>n<strong>in</strong>g<br />
of the differential pump<strong>in</strong>g tube allow for mount<strong>in</strong>g of the Zeeman slower coils on an<br />
additional tube.<br />
A tube hold<strong>in</strong>g the Zeeman slower coils has <strong>to</strong> slide over the differential pump<strong>in</strong>g<br />
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