  We study orbital entanglement production in a chaotic cavity connected to
four single-channel normal-metal leads and one superconducting lead, assuming
the presence of time-reversal symmetry (TRS). The scattered state of two
incident electrons is written as the superposition of several two-outgoing
quasi-particle states, four of which are orbitally entangled in a left-right
bipartition. We calculate numerically the mean value of the squared norm of
each scattered state's component, as functions of the number of channels in the
superconducting lead. Its behavior is explained as resulting from the proximity
effect. We also study statistically the amount of entanglement carried by each
pair of outgoing quasi-particles. When the influence of the superconductor is
more intense, the average entanglement is found to be considerably larger than
that obtained using normal cavities.
