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Tracking efficiency for PXL (y2013)

Updated on Sun, 2013-03-31 11:05. Originally created by bouchet on 2013-03-30 14:44.
I have reported in the last 2 hft soft meetings a tracking efficiency of ~70%
The efficiency is defined as  :
# of hits used in tracking / all hits
There were some concerns why it is that low. People suggested a different simulation input.
The following had been used :
  1. 1GeV muon with ~ fixed azimuthal angle to be sure that it hits a sensitive area
1) Simulation setup
kumac used : 1 muon per event
 detp geom y2013
 gexec .$STAR_HOST_SYS/lib/xgeometry.so
 gclose all
 user/vxyz 0.001 0.001 .01
 user/vsig .01 .1
 gfile o muon_1gev.fz
 aguser/gkine 1 5 1.0 1.0 -1.0 +1.0 1.7 1.7
 trig 50
Here the azimutal angle is 1.7 radians, which is located ~ the first ladder of the first sector. (see plots below)

2) Results
Plot : Y vs. X positions of all PXL hits (as saved in StEvent)



Plot : Y vs. X positions of PXL hits used in tracking.


note : isUsed() method derives from StHit
int StHit::usedInFit() const { return static_cast<int>(mFitFlag); }
Comments :
  1. over 50 events, there are 99 PXL hits
  2. over 99 PXL hits, 96 are used in tracking (making an efficiency close to 100%)
3) details per event
Details are below :

 event : 1   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 2   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 3   ==> # of hits : 3   ==> # of hits used : 2   ==>ratio :0.666667
 event : 4   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 5   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 6   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 7   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 8   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 9   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 10   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 11   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 12   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 13   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 14   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 15   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 16   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 17   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 18   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 19   ==> # of hits : 1   ==> # of hits used : 0   ==>ratio :0
 event : 20   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 21   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 22   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 23   ==> # of hits : 1   ==> # of hits used : 0   ==>ratio :0
 event : 24   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 25   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 26   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 27   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 28   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 29   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 30   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 31   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 32   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 33   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 34   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 35   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 36   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 37   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 38   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 39   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 40   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 41   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 42   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 43   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 44   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 45   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 46   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 47   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 48   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 49   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1
 event : 50   ==> # of hits : 2   ==> # of hits used : 2   ==>ratio :1

Over the 50 events :
  1. 1 event has 66% efficiency tracking because the track has orginally 3 PXL hits and 2 fitted
  2. events for which efficiency=0 are events for which the number of PXL hits is 1
  3. there are no events with 2 PXL hits and only 1 fitted (due to the very low density of tracks)
4) closer look at event 3

This event has :
  1. 3 PXL hits
  2. 2 PXL hits used in tracking
The details are below :
root.exe [4] anaTree->Scan("x:y:z:sector:ladder:isUsed","event==3")
************************************************************************************
*    Row   *         x *         y *         z *    sector *    ladder *    isUsed *
************************************************************************************
*        4 * -1.007043 * 8.1190853 * -4.377455 *         1 *         1 *         1 *
*        5 * -0.996199 * 8.1171770 * -4.375775 *         1 *         1 *         0 *
*        6 * -0.325882 * 2.5432992 * -1.478665 *         1 *         4 *         1 *
************************************************************************************
comments :
  1. There are 2 hits in ladder 1 very closed each other (one may be due to interaction = fake hit)
  2. But the hit in the inner layer (more important) is used in tracking.






 

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