Experiments with Supersonic Beams as a Source of Cold Atoms

Figure 3.7: A CAD image of the rotor. The rotor has 50.4 cm radius at the center of
the crystal holder, and a maximum thickness of 2.54 cm in the center. The diameter
of the rotor itself is linearly tapered from 0.3175 cm where the rotor joins the crystal
holder, to the maximal thickness 2.54 cm from the middle of the rotor. The small
hole seen in the middle of the rotor allows precise centering of the rotor via a pin in
the spindle. A 5 mm diameter crystal (4 mm exposed) is held in place by a set screw.
Figure Courtesy Max Riedel.
Figure 3.8: A finite element calculation of the stress exerted on the rotor by rotation
at 140 Hz. This is expressed in MPa, since it is the force per unit area of material,
rather than the absolute force, which is relevant. For reference, the peak stress place
on the rotor is only a factor of 5 smaller than the yield tensile strength of the titanium
alloy used.
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