Martin Teichmann Atomes de lithium-6 ultra froids dans la ... - TEL

3.2. THE ZEEMAN SLOWER
Figure 3.2: The Zeeman slower while being wound. One can see the layer
structure of the coils. The cables are held in place using a cement mixed
with silicon carbide, which gives a grey color. On the right on can see the
end of the two parallel water cooling tubes which are below the coils.
stop functioning with time, one could consider using this layer instead.
For cooling, we wound a layer of two parallel copper tubes with an
outer diameter of 8 mm around the first layer. The two parallel tubes
should increase the water flux by a factor of four compared to a single
tube. After seven layers of cables, we added another cooling layer, and
another cooling layer at the end.
The light for the Zeeman slower enters through a window at the end
of the vacuum chamber. This window is under constant bombardment
from lithium atoms from the jet. After many years of operation, this
window was slightly covered with lithium. Not that it had prevented
us from working, but as the chamber was already open, we decided
to replace it with an anti-reflection coated window, hoping to improve
the efficiency of the Zeeman slower. We were surprised that after only
a few weeks the window was completely covered, the anti-reflection
coating had apparently reacted with the lithium, and we had to replace
it by a non-coated window, which works fine.
Once wound, we characterized the performance of the slower by
measuring the velocity distribution of the atoms at the end as follows:
When we shine a resonant laser onto the atom jet, the atoms will
fluoresce. From the fluorescence we can measure the flux of atoms in
the laser beam We do not adjust the laser beam perpendicular to the
atomic jet, but leave a slight angle between the orthogonal of the jet
and the laser beam. Then those atoms will fluoresce, whose Doppler
45