  New generation high-energy physics experiments demand high precision tracking
and accurate measurements of a large number of particles produced in the
collisions of lementary particles and heavy-ions. Silicon-tungsten (Si-W)
calorimeters provide the most viable technological option to meet the
requirements of particle detection in high multiplicity environments. We report
a novel Si-W calorimeter design, which is optimized for $\gamma/\pi^0$
discrimination up to high momenta. In order to test the feasibility of the
calorimeter, a prototype mini-tower was constructed using silicon pad detector
arrays and tungsten layers. The performance of the mini-tower was tested using
pion and electron beams at the CERN Proton Synchrotron (PS). The experimental
results are compared with the results from a detailed GEANT-4 simulation. A
linear relationship between the observed energy deposition and simulated
response of the mini-tower has been obtained, in line with our expectations.
