Files used : /star/data10/reco/cuProductionMinBias/FullField/P05if_test/2005/049/st_physics_6049032_raw_1010008.event.root

Here are the residuals in Z ,X and Y and are defined as :

difference between the coordinates of the first hit and the dca point of the helix fit to the first point == hit position - helix position

(Click on the picture to enlarge. A new window will open.)

Not includind ssd points in the tracking

Picture 1: residual in Z | Picture 2: residual in X | Picture 3: residual in Y |

(Click on the picture to enlarge. A new window will open.)

Includind ssd points in the tracking

Picture 1: residual in Z | Picture 2: residual in X | Picture 3: residual in Y |

Comments : this is very preliminary and this is not final results because there are still stuffs to fix :

- need more stats
- if the ssd is not well aligned , then we associate wrong hits
- the hit association is using , for the ssd , the defaults parameters which are for the resolution in Z = 20 microns and in X/Y = 20 microns but we must use real resolution which are 700 microns in Z and 20 microns in X/Y

I can load differents parameters from a .dat file from StiMaker/macros/ssdInputFile.dat but this is private code and this is still a thing I have to do

- In Sti/StiHitErrorCalculator.cxx : there is a shift between parameters in Z and X/Y

These parameters are clearly define as :

coeff[0]= intrinsicZ;

coeff[1]= driftZ;

coeff[2]= crossZ;

coeff[3]= intrinsicX;

coeff[4]= driftX;

coeff[5]= crossX;

then it calculates :

ecross=coeff[0]+coeff[1]*dz/(cosCA*cosCA) +coeff[2]*tanCA*tanCA;

if (ecross< 1e-4) ecross = 1e-4;

if (ecross> 1 ) ecross = 1;

double tanDip=node->getTanL();

double cosDipInv2=1+tanDip*tanDip;

edip=coeff[3]+coeff[4]*dz*cosDipInv2+coeff[5]*tanDip*tanDip;

My problem is that in this formula for the calculation of edip , it uses coef[3],coef[4],coef[5] ,whereas it must use coef[0],coef[1],coef[2] ( which are the parameters for the Z axis I hope) ?

edip == delta ( Z ) because there are uses both the dip Angle and delta(Z) uses all the parameters linked to the Z Axis but here , it seems that edip is not uses the good parameters.

- 0 == there are hits in tpc for this primary
- 1== there are hits in tpc and svt
- 2== there are hits in tpc and ssd
- 3== there are hits in svt and ssd
- 4== there are hits in tpc, svt, ssd

(Click on the picture to enlarge. A new window will open.)

Picture 1: dca (tpc+svt) | Picture 2: dca (tpc+svt+ssd) |

Jonathan Bouchet Last modified: Wed Oct 4 15:46:34 CEST 2005