[en] This thesis focuses on the GLUEX Barrel Calorimeter (BCAL), a key subsystem of the GLUEX experiment, which is currently under construction. GLUEX will shed light on an as yet unexplored area of the interaction between the fundamental constituents of matter, that of confinement. To achieve its goals, GLUEX requires a hermetic detector with good acceptance and good energy and position resolution. To that end, a lot of effort has been spent on R&D in order to optimize the performance of the BCAL. Specifically, the effect of the thickness of the lead sheets, used to build the BCAL, on the performance of the BCAL was simulated using Monte Carlo techniques. Using the GEANT simulation package, three different geometry configurations were simulated and the shape of the longitudinal shower profile, energy resolution and the fractional energy deposition and energy leakage were extracted and the results comprise the first half of this thesis. The second half of the thesis consists of an analysis of data collected in 2006 from a beam test performed at Jefferson Lab on a BCAL prototype module. The analysis was done in order to extract the energy resolution for several different angles of incidence, including the 90° which was used as reference. (author)