  In gamma ray astronomy, the energy range from sub-100GeV to TeV is crucial
due to where there is a gap between space experiments and ground-based ones. In
addition, observations in this energy range are expected to provide more
details about the high energy emission from GRBs,and thus to understand EBL.
Based on the observation results and the related knowledge, scientists may be
able to unveil the mysteries of galaxy formation and the evolution of early
universe. One of the principal issues for next generation Imaging Atmospheric
Cherenkov Telescopes (IACT) is to achieve larger field of view (FoV). In this
work, we report a refractive water convex lens as light collector to test the
feasibility of a new generation of IACT, and some preliminary test results on
the optical properties (the focal length, spot size, transmittance, etc.) of a
0.9 m diameter water lens, the photodetectors and DAQ system of a prototype are
presented and discussed.
