Variation of 6 FGT disks configuration A

Resulting track, charge reco efficiency and contamination for electrons w/ pt=30 GeV/c.

1. Variation of FGT resolution: 60,80,100,120 mum.
Conclusion: small degradation at eta>1.8 charge reco drops to 70%.
track Eff= N1/N0 charg eff = N2/N0 wrong charge (N1-N2)/N1
The reference: Config A : 6 FGT disks w/ sig=60mum, no FST
Config A1 : 6 FGT disks w/ sig=80mum, no FST
Config A2 : 6 FGT disks w/ sig=100mum, no FST
Config A3 : 6 FGT disks w/ sig=120mum, no FST

2. Variation of Vertex point resolution: 0.5mm , 1mm in 3D, or 30cm only in Z. Default is 0.2mm in X=Y=Z.
Conclusion: If the transverse vertex position (beamLine) has sig=0.5mm ~10% of tracks at eta>1.8 will have error in reco phi,eta direction above 3 mrd
Z-vertex position from BBC timing is good enough.
track Eff= N1/N0 charg eff = N2/N0 wrong charge (N1-N2)/N1
Config A4 : Vertex sigX=Y=Z=0.5mm
Config A5 : Vertex sigX=Y=Z=1mm
Config A6 : Vertex sigX=Y0.2mm sigZ=30cm. I see no difference vs. config=A - as expected.

3. Variation of FGT disk efficiency: 90%, 85% per disk.
track Eff= N1/N0 charg eff = N2/N0 wrong charge (N1-N2)/N1
Config A7 : FGT disk effi=90%. Note: 0.9^6=0.53, 0.9^5=0.59
Config A8 : FGT disk effi=85%. Note, 0.85^6=0.38, 0.85^5=0.44