In the fast simulator, MC hits are not written to StEvent if they fall outside the active areas of the wafer after the hits smearing.
Smearing values are (in local) :

• 30 microns in r/phi
• 800 microns in Z

There are 2 inactive areas to be considered (as shown here)

• border of the wafer
• triangle area due to strips crossing

Simulation :

• 200 events
• 100 pions per events with 0<Pt<5GeV/c
• y2014a geometry, StSstFastSimMaker, DEV

Fig1 : dX = xL - xL (after smearing)


Fig2 : dZ = zL - zL (after smearing)


Fig3 : ratio of hits in active area after smearing over the # MC hits input


Fig4 : same as Fig3 but zoomed

Test w/o smearing the hits (will test only the removal of hits due to inactive areas)

Black : without smearing (mean_histo = 0.998)
red : with smearing (mean_histo = 0.978)