Experiments with Supersonic Beams as a Source of Cold Atoms

field can be seen in figure 5.6. There are two curves shown here, one for the initial
pulse, and one after the wires and resistors in the circuit have heated up by pulsing
the coil at a .5 Hz repetition rate.
One other change made from the coilgun used to slow neon and oxygen is in
the control electronics. The larger coils of the hydrogen slower mean that the timing
resolution needed in the control circuitry is reduced. Simulations show that the
timing resolution of 100ns used in the 64 stage coilgun does not have any benefit over
a much easier to implement 1 μs resolution. Because the experiment is controlled by
LabVIEW, it is simpler to use LabVIEW and National Instruments data acquisition
cards (NI PCIe-6259) to control the coil timing, rather than using LabVIEW for data
acquisition and an FPGA for control.
5.2.2 Trapping Coils and Electronics
The experimental goals require trapping the slowed hydrogen atoms at the
end of the coilgun, and so the experiment must incorporate a trapping potential and
a method of bringing the atoms to rest at the center of that potential. Because the
coilgun operates on low-field-seekers, the slowed atoms are already in a magnetically
trappable state, and state preparation between the coilgun and the trap is not nec-
essary. A static magnetic trap is a conservative potential, and the atoms must first
be brought to rest in the trapping volume. The proposed trapping sequence this is
explained in this section. The details of the anti-Helmholtz magnetic trap and the
switching circuitry built to control the magnetic potentials created by the trapping
coils are described.
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