Experiments with Supersonic Beams as a Source of Cold Atoms

diameter and 17.8 mm outer diameter. The coil is held together with Epo-Tek H77
UHV compatible, thermally conductive, and electrically insulating epoxy. A blow up
of the components which surround the coil is presented in figure 4.20.
To wind the coils, the Permendur discs, Kapton washers, and Vespel cylinder
are placed on a winding tool. The coil is then wound in the gap between the Kapton
washers, around the Vespel cylinder. Shrink wrap Teflon is placed around the wire
where it enters and exits the coil to provide further protect at these locations, which
were found to be particularly prone to scratching. Once the coil is wound, it is
removed from the winding tool, and is placed onto a 3 mm diameter Teflon rod. The
rod is anchored in a Teflon mold which includes a groove that allows the wires to
exit the coil. The top Permendur disc and Kapton washer are removed, and the
magnetic steel cylinder shell is placed over the coil. At this point the epoxy is applied
to the coil windings using a small Teflon spatula. The epoxy is quite viscous at room
temperature, but heating the coil to 50 ◦ C with a heat gun reduces the viscosity
enough that the epoxy flows around the coil windings. The 3 mm diameter Teflon
rod the coil sits on keeps the epoxy from flowing into the coil bore. The top Kapton
washer and Permendur disc are then put in place and the entire assembly is clamped
in place with another Teflon mold held in position with a C-clamp. The coil is then
baked for 3 hours at 150 ◦ C to cure the epoxy. Once the coils have cooled, the clamps
are removed and the excess epoxy is removed using pliers. Lastly, any remaining
epoxy is removed by sanding the outside of the coil by hand. The coil assembly
sequence is shown in figure 4.21.
After the coils are assembled, they are tested for short circuits and for scratched
insulation on the wires. This is done by placing the assembled coil in a beaker of
methanol. A multimeter is used to measure the resistance between the coil wire and
the methanol. Since the methanol will flow around the coil, and around the steel and
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