Charge reco efficiency for 40 GeV e- using 6-disk FGT as implemented in UPGR13
Updated: April 3, 2007

All plots on this page are produced for a single electron events with pT of 40 GeV/c.

  1. Input: one-electron events.
    Generated electrons have fixed pT and zVertex of -30, 0, or +30 cm, and uniform 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 ,
    Combined 3Z locations:

    The plot shows 9 electrons with fixed pT=40 GeV/c, Z={-30,0,+30}cm, and eta={1.0,1.5,2.0}

  2. Assumptions about resolution of detectors.
    * Use: Vertex, IST1+2, SSD, 6-disk FGT, truncated TPC(nHit>=5), ESMD
    detector assumed resolution weight of the point Remarks
    vertex 200 mu m in X,Y
    30 cm in Z
    W=1/(200 mu m)^2 added as a hit
    IST1 20 mum in r*phi
    0.5 mm in Z
    W=1/(20 mu m)^2 -
    IST2 0.5 mm in r*phi
    20 mum in Z
    W=1/(0.5 mm)^2 -
    SSD 20 mum in r*phi
    1 mm in Z
    W=1/(20 mu m)^2 -
    FGT 60 mu m in X,Y
    1 mm in Z
    W=1/(60 mu m)^2 6 disks
    hit reco eff=100%
    TPC 1 mm along arc
    1 mm in Z
    W=1/(1mm)^2 * drop padrow #1 and #13
    * drop hits at |Z|>197 cm
    * drop all hits if below 5
    Endcap SMD
    mock hit **)
    1.5 mm in X,Y
    5mm in Z
    W=1/(1.5 mm)^2 at xPoint of Geant helix
    w/ SMD plane

    **) Based on SMD response study by Jim

  3. Hit distribution (Rxy vs.eta) for 3 vertex locations( -30cm, 0, +30 cm), shown for config=A. IST+SSD and FGT are off for configs B,C. Config D has FGT disk at different Z-location and IST+SSD is off.

  4. The following detector configuartions have been considered
             A :  default 
             B :  no IST, no SSD
             C :  only TPC+SMD+VERT
             D :  no IST, no SSD, variable FGT(Z) 

  5. Quality of the reco 3D tracks (fit of circle+line) is defined based on a difference of the reco direction of primary track at the vertex vs. Geant track direction.

    Track reco efficiency is defined as the ratio of# of reco tracks (N1) w/
    * nFitP>=5, including vertex as a hit
    * delPhi<3 mrad
    * delTheta <3 mrad
    to the # of generated electrons (N0).

    Charge reco efficiency requiers additinal
    * the sign of the reco charge is correct. Track counter is N2.
    No cut on reco pT is imposed.

  6. Resulting track, charge reco efficiency and contamination for electrons w/ pt=40 GeV/c, flat in eta [0.5,2.5], flat in phi in 2*pi, 5K events per sample
    Note, we do not want to be in the magenta sqare.
    track Eff= N1/N0 charg eff = N2/N0 wrong charge (N1-N2)/N1 Geant Pt - Reco Pt , matched in delEta & delPhi
    Config A : all in: Vertex, IST1+2, SSD, FGT, TPC , ESMD
    Config B : drop IST, drop SSD
    Config C : use only TPC+ESMD+Vertex