  We are developing gaseous photon detectors for Cherenkov imaging applications
in the experiments at the future Electron Ion Collider. CsI, converting photons
in the far ultraviolet range, is, so far, the only photoconverter compatible
with the operation of gaseous detectors. It is very delicate to handle due to
its hygroscopic nature: the absorbed water vapour decomposes the CsI molecule.
In addition, its quantum efficiency degrades under ion bombardment. These are
the key reasons to quest for novel, less delicate materials for photocathodes
adequate for gaseous photon detectors. Layers of hydrogenated nanodiamond
particles have recently been proposed as an alternative material and have shown
promising characteristics. The performance of nanodiamond photocathodes coupled
to thick GEM-based detectors is the object of our ongoing R\&D. The first phase
of these studies includes the characterization of thick GEM coated with
nanodiamond layers and the robustness of its photoconverting properties with
respect to the bombardment by ions from the multiplication process in the
gaseous detector. The approach is described in detail as well as all the
results obtained so far within these exploratory studies.
