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Run14 - (TPC Track - HFT Hit) Matching Studies

Updated on Wed, 2014-03-12 10:10. Originally created by dongx on 2014-03-11 23:47.

 The following studies are based on the data processed on March 10.

1) Cosmic data with reversed full field magnetic field. Run # 15040032
Reconstruction chain options:

ry2014,in,tpcX,AgML,tpcDB,TpcHitMover,Idst,Tree,evout,ITTF,UseXgeom,BAna,l3onl,trgd,ZDCvtx,NosvtIt,NossdIt,analysis,pxlRaw,pxlDb,pxlCluster,pxlHit,istRaw,istDb,istCluster,istHit,Corr4,HftMatTree

Source codes are located here:

/star/institutions/lbl/dongx/hft/Run14/Cosmic_Data_FieldOn
Log files are here:
output/15040032/st_cosmic_adc_15040032*.out

The following plots show the local residual distributions between the projected position from the TPC to IST and the measured hit position on IST.


zLP:  projected position using TPC tracks in the local CS of HFT
zL:  measured position of HFT hits in the local CS of HFT
 

The two majors peaks in the local residual-Z are mainly coming from positive and negative eta region, indicating there is likely a T0 offset in the TPC calibration. There might be a dependence vs eta for each band meaning probably the drift velocity calibration can be improved too.

The mis-match can be viewed more directly through the following event display.

The two figures are from the same cosmic ray event (blue plate is the central membrane). The left plot clearly shows a mis-match between the two TPC tracks from the same cosmic ray. The right plot magnifies the region on the IST (white dots are the measured IST hits). One can see the two hits w.r.t. the track projection are shifted towards the opposite directions.

The following figures show the local z matching between TPC projections and the hits measured at the PXL, which illustrates the similar behavior.

2) AuAu 15 GeV data with reversed full field. Run # 15049075 with IST/PXL included in the run.
Reconstruction chain options (similar as in 1), added in the TPC space charge correction etc.)

ry2014,in,tpcX,AgML,tpcDB,TpcHitMover,Idst,Tree,evout,ITTF,UseXgeom,BAna,l3onl,trgd,ZDCvtx,NosvtIt,NossdIt,analysis,pxlRaw,pxlDb,pxlCluster,pxlHit,istRaw,istDb,istCluster,istHit,Corr4,btof,BEmcChkStat,OSpaceZ2,OGridLeak3D,HftMatTree

Source codes are located here:

/star/institutions/lbl/dongx/hft/Run14/AuAu15
Log files are here:
output/15049075/st_physics_*.out

Similarly we show the local residual-Z distributions in IST for events with low multipliicity (to avoid large combinatorial background).

The statistics is not so great, but one can generally see the similar trend as observed in the cosmic ray events shown in 1).

 

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