) and PC (see Figure 2 
) planes show a peak in the center of the detector where the majority of
particle tracks pass.  Between upstream and downstream (see Figure 3 
) DC planes there is a widening of the cross talk occupancy curve, as the
positrons travel through a larger area of the detector due to their helical
tracks.  The same instrumentation restrictions of the planes are placed on
the histograms, as described in Section  
.