Study of track & charge reconstruction for high energy electrons using geometry UPGR12
All plots on this page are produced for a single electron events with pT of 20 GeV/c.
- Input one-electron events.
Generated electrons have fixed pT and zVertex of -30, 0, or +30 cm,and flat eta and phi distribution. Sample of high pT electrons thrown from different zVertex location over eta range [1,2] are shown here:
Z=-30cm ,
Z=0cm ,
Z=+30cm.,
- Assumptions about resolution of detectors. Positions of GEANT hits were smeared with resolution...
Table 1.
detector | assumed resolution | weight of the point | Remarks
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FST,FGT | 60 mu m in X,Y 10 mu in Z | W=1/(60mu m)^2 | 4 disks
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TPC | 1 mm along arc 1 mm in Z | W=1/(1mm)^2 | drop padrow #1, #13 drop hits at |Z|>197 cm
|
vertex | 200 mu m in X,Y,Z | W=1/(200 mu m)^2 | added as a hit
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- # of available hits from FST,FGT, and TPC as function of pseudrapidity (X-Axis)
and assumed Z-vertex position ( red=- 3cm, green=0, blue= +30 cm)
detector | # of hits vs eta
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FST |
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FGT |
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TPC |
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all+ vertex |
5 hits limit to find the helix is marked by the red line
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- Chi2/DOF for Circle fit vs. eta, separate for 3 Z-vertex locations.
Note, DOF changes w/ eta (see above) so the shape of chi2/DOF changes as well.
- Quality of the reco 3D tracks (fit of circle+line) can be measured as a difference of the reco direction of primary track at the vertex vs. Geant direction. I choose angles: theta & phi, in radians.
- Track reco efficiency is defined as the ratio of geant electrons to # of reco tracks w/
* nFitP>=5, including vertex as a hit
* delPhi<3 mrad
* delTheta <3 mrad
Note, at the Endcap SMD plane (Z~300cm) 3 mrad translate to 1cm displacement of reco track vs. projected ideal helix.
- Charge reco efficiency requires additional the sign of the reco track is correct. No cut on reco pT is imposed.
Pt=20 GeV/c | Pt=40 GeV/c
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Used macro pl3Z.C