Experiments with Supersonic Beams as a Source of Cold Atoms

Figure 5.18: A CAD image of the complete hydrogen apparatus.
tion. The front of the ionizer sits 6.04cm from the center of the trapping volume, and
only 1.01 cm from the beam’s entrance to the detection chamber. Atoms are ionized,
and steered by ion optics though a 90 ◦ turn into the quadrupole mass filter. They
are detected by an electron multiplier at the base of the quadrupole. The detection
chamber also provides pumping for the unslowed portion of the supersonic beam. If
the trapping chamber were terminated without the detection chamber, the gas in
the beam would quickly fill the small volume of the slowing and trapping chamber,
raising the vacuum pressure significantly. Having the detection chamber (with ≈ 10L
volume) which is pumped by a 500 l/s as a beam dump volume allows the pressure
in the trapping volume to stay below 2 × 10 −9 torr. A CAD image of the detection
chamber is shown in figure 5.17, and the complete apparatus is shown in figure 5.18.
5.3 Simulations of Hydrogen Trapping
The device described above is designed to maximize the phase space density
of the trapped hydrogen. Numerical simulations of the slowing and trapping process
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