  Fluorescent Dark Matter has been suggested as a possible explanation of both
the 3.5 keV excess in the diffuse emission of the Perseus Cluster and of the
deficit at the same energy in the central active galaxy within that cluster,
NGC 1275. In this work we point out that such a dark matter candidate can be
searched for at the new X-ray laser facilities that are currently being built
and starting to operate around the world. We present one possible experimental
set up where the laser is passed through a narrow cylinder lined with lead
shielding. Flourescent Dark Matter would be excited upon interaction with the
laser photons and travel across the lead shielding to decay outside the
cylinder, in a region which has been instrumented with X-ray detectors. For an
instrumented length of 7cm at the LCLS-II laser we expect $\mathcal{O} (1 -
10)$ such events per week for parameters which explain the astronomical
observations.
