  We show under what conditions an accelerated detector (e.g., an
atom/ion/molecule) thermalizes while interacting with the vacuum state of a
quantum field in a setup where the detector's acceleration alternates sign
across multiple optical cavities. We show (non-perturbatively) in what regimes
the probe `forgets' that it is traversing cavities and thermalizes to a
temperature proportional to its acceleration. Then we analyze in detail how
this thermalization relates to the renowned Unruh effect. Finally, we use these
results to propose an experimental testbed for the direct detection of the
Unruh effect at relatively low probe speeds and accelerations, potentially
orders of magnitude below previous proposals.
