  We report on results of observation of the focusing effect from the planes
(220) of Gallium Arsenide (GaAs) crystals. We have compared the experimental
results with the simulations of the focusing capability of GaAs tiles through a
developed Monte Carlo. The GaAs tiles were bent using a lapping process
developed at the cnr/imem - Parma (Italy) in the framework of the laue project,
funded by ASI, dedicated to build a broad band Laue lens prototype for
astrophysical applications in the hard X-/soft gamma-ray energy range (80-600
keV). We present and discuss the results obtained from their characterization,
mainly in terms of focusing capability. Bent crystals will significantly
increase the signal to noise ratio of a telescope based on a Laue lens,
consequently leading to an unprecedented enhancement of sensitivity with
respect to the present non focusing instrumentation.
