  Muography is an innovative imaging technique using naturally produced
elementary particles -- atmospheric muons -- like the X-rays of medical
imaging. The modification of the particles flux -- by scattering or absorption
--, reflects the contrasts in density within the medium and therefore offers
the possibility for an image of the crossed volumes. The imaging process is
based on the tracking of the particles which accounts for the absorption or the
scattering of the muons trajectories. Neither the energy nor the identity of
the particles (the so-called PID) is exploited since this information
traditionally relies on the use of calorimeters and/or high intensity magnetic
fields. Both these techniques hinder detector portability which in the case of
muography is important and this renders them impractical for its purpose. In
this paper we characterize the performance of a simple and small water
Cherenkov detector capable on the one hand of providing some insights on energy
and PID and on the other hand of improving the background rejection for a muon
telescope. We tested a prototype of such water Cherenkov detector in
combination with two small muon hodoscopes. Both systems are using the same
opto-electronics chain -- optical fibers and pixellized photosensors -- and the
same data acquisition (DAQ) readout system which ensures an easy integration
and implementation within presently running systems. This article presents the
test setup, the detector response to cosmic muons and its performance
evaluation against a basic simulation of its geometry and detection principle.
