Experiments with Supersonic Beams as a Source of Cold Atoms

sequence was simulated for 3,000 trapped atoms (their trajectories in the trap are
determined by previous simulations), and a simulated time-of-flight profile of atoms
arriving at the detector is presented in figure 5.21. Of the 3,000 simulated atoms, 406
propagate into the detection volume, giving an efficiency of 13%, which is a significant
improvement over releasing the trap.
5.4 Future Directions
While the experiment described above has been constructed and characterized,
it has so far been unable to detect trapped hydrogen using the Ardara ionizer and
quadrupole. The primary reason for this is thought to be the large background signal
due to hydrogen gas in the detection volume. An alternative detection method is
to use a laser to excite the trapped hydrogen atoms to a metastable state, and to
detect the metastable atoms with an MCP, which should be background free. This
detection method and the progress made to date on implementing laser detection
in the experiment are described in this section. Once trapped hydrogen has been
detected, the initial goal of the experiment is to investigate the isotopic shift of
atomic tritium, which should provide information on the charge radius and structure
of the triton.
In addition to spectroscopy, research will continue on improving the coilgun
method of trapping particles cooled by a supersonic beam. In particular, a method of
creating a moving magnetic trap which is decelerated should increase the phase space
density of the trapped sample significantly. A moving trap confines the particles in all
three dimensions throughout the deceleration and trapping process, thus preserving
the initial phase space denisty of the beam at the enterance of the slower.
Finally, a cooling method for magnetically trapped hydrogen isotopes is dis-
cussed. The proposed scheme is based on single-photon cooling, which uses a single
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