There are 4 different mirrors with the sngle that photons reflect off of them displayed here. This is kinematics dependent, so a perpendicular pion and a theta = 4, phi = 40 pion are shown. The side mirror reflections are shown as if every photon relfects once from the side - the exact number that reflect depend on the bar, with bars closer to the beamline having fewer reflections at small angles. Note that less than 10% of the photons reflect off of the upper wedge.
Theta = 4, Phi = 40:
Perpendicular track: