Experiments with Supersonic Beams as a Source of Cold Atoms

Z − Velocity (m/s)
100
60
30
0
−30
−60
−10 -6 -2 0 2 6 10
Z − Position (mm)
Y − Velocity (m/s)
60
40
20
0
−20
−40
−60
−4 −3 −2 −1 0 1 2 3 4
Y − Position (mm)
X − Velocity (m/s)
60
40
20
0
−20
−40
−60
−4 −3 −2 −1 0 1 2 3 4
X − Position (mm)
Figure 5.20: Simulated phase space distributions of the trapped hydrogen atoms. Of
the 10,000 simulated atoms that enter the coilgun, 481 remain in the trapping volume
for 10ms (around 10 oscillation periods) after the trap is turned on. The temperature
of the trapped atoms is calculated to be 62 mK. Included in the figures is an ellipse
which encloses the region of phase space which is lower than the overall trap depth.
While the X and Y phase space distributions are contained in this region, the Z
distribution is not. Atoms with energies in the Z direction that are greater than the
overall trap depth can remain in the trap because the trap is significantly deeper in
the Z direction, and the velocity components are not well mixed.
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