**************************************************************************/
/* $Id$ */
-
///////////////////////////////////////////////////////////////////////////////
// //
// //
///////////////////////////////////////////////////////////////////////////////
-#include "TMath.h"
+#include <TMath.h>
#include "AliLog.h"
+
#include "AliTRDcluster.h"
#include "AliTRDgeometry.h"
#include "AliTRDCommonParam.h"
+#include "AliTRDtrackletWord.h"
ClassImp(AliTRDcluster)
for (Int_t i = 0; i < 7; i++) {
fSignals[i] = 0;
}
-
+ SetBit(kLUT);
}
//___________________________________________________________________________
-AliTRDcluster::AliTRDcluster(Int_t det, UChar_t col, UChar_t row, UChar_t time, const Short_t *sig, UShort_t vid)
+AliTRDcluster::AliTRDcluster(Int_t det, UChar_t col, UChar_t row, UChar_t time
+ , const Short_t *sig, UShort_t vid)
:AliCluster()
,fPadCol(col)
,fPadRow(row)
memcpy(&fSignals, sig, 7*sizeof(Short_t));
fQ = fSignals[2]+fSignals[3]+fSignals[4];
SetVolumeId(vid);
+ SetBit(kLUT);
}
//___________________________________________________________________________
AliTRDcluster::AliTRDcluster(Int_t det, Float_t q
, Float_t *pos, Float_t *sig
- , Int_t *tracks, Char_t npads, Short_t *signals
+ , Int_t *tracks, Char_t npads, Short_t * const signals
, UChar_t col, UChar_t row, UChar_t time
, Char_t timebin, Float_t center, UShort_t volid)
:AliCluster(volid,pos[0],pos[1],pos[2],sig[0],sig[1],0.0,0x0)
if (tracks) {
AddTrackIndex(tracks);
}
+ SetBit(kLUT);
+}
+
+//_____________________________________________________________________________
+AliTRDcluster::AliTRDcluster(const AliTRDtrackletWord *const tracklet, Int_t det, UShort_t volid)
+ :AliCluster(volid,tracklet->GetX(),tracklet->GetY(),tracklet->GetZ(),0,0,0)
+ ,fPadCol(0)
+ ,fPadRow(0)
+ ,fPadTime(0)
+ ,fLocalTimeBin(0)
+ ,fNPads(0)
+ ,fClusterMasking(0)
+ ,fDetector(det)
+ ,fQ(0.)
+ ,fCenter(0.)
+{
+ //
+ // Constructor from online tracklet
+ //
+
+ for (Int_t i = 0; i < 7; i++) {
+ fSignals[i] = 0;
+ }
}
// Copy constructor
//
- SetBit(kInChamber, c.IsInChamber());
SetLabel(c.GetLabel(0),0);
SetLabel(c.GetLabel(1),1);
SetLabel(c.GetLabel(2),2);
SetY(c.GetY());
SetZ(c.GetZ());
- SetSigmaY2(c.GetSigmaY2());
+ AliCluster::SetSigmaY2(c.GetSigmaY2());
SetSigmaZ2(c.GetSigmaZ2());
for (Int_t i = 0; i < 7; i++) {
}
//_____________________________________________________________________________
-void AliTRDcluster::AddTrackIndex(Int_t *track)
+AliTRDcluster &AliTRDcluster::operator=(const AliTRDcluster &c)
+{
+ //
+ // Assignment operator
+ //
+
+ if (&c == this) {
+ return *this;
+ }
+
+ // Call the assignment operator of the base class
+ AliCluster::operator=(c);
+
+ fPadCol = c.fPadCol;
+ fPadRow = c.fPadRow;
+ fPadTime = c.fPadTime;
+ fLocalTimeBin = c.fLocalTimeBin;
+ fNPads = c.fNPads;
+ fClusterMasking = c.fClusterMasking;
+ fDetector = c.fDetector;
+ fQ = c.fQ;
+ fCenter = c.fCenter;
+
+ SetLabel(c.GetLabel(0),0);
+ SetLabel(c.GetLabel(1),1);
+ SetLabel(c.GetLabel(2),2);
+
+ SetY(c.GetY());
+ SetZ(c.GetZ());
+ SetSigmaZ2(c.GetSigmaZ2());
+
+ for (Int_t i = 0; i < 7; i++) {
+ fSignals[i] = c.fSignals[i];
+ }
+
+ return *this;
+
+}
+
+//_____________________________________________________________________________
+void AliTRDcluster::AddTrackIndex(const Int_t * const track)
{
//
// Adds track index. Currently assumed that track is an array of
fQ = 0;
fCenter = 0;
for (Int_t i = 0; i < 3; i++) SetLabel(0,i);
- SetX(0);
- SetY(0);
- SetZ(0);
- SetSigmaY2(0);
- SetSigmaZ2(0);
+ SetX(0.);
+ SetY(0.);
+ SetZ(0.);
+ AliCluster::SetSigmaY2(0.);
+ SetSigmaZ2(0.);
SetVolumeId(0);
}
//___________________________________________________________________________
Double_t AliTRDcluster::GetSX(Int_t tb, Double_t z)
{
+ //
+ // Returns the error parameterization in the radial direction for TRD clusters as function of
+ // the calibrated time bin (tb) and optionally distance to anode wire (z). By default (no z information)
+ // the mean value over all cluster to wire distance is chosen.
+ //
+ // There are several contributions which are entering in the definition of the radial errors of the clusters.
+ // Although an analytic defition should be possible for the moment this is not yet available but instead a
+ // numerical parameterization is provided (see AliTRDclusterResolution::ProcessSigma() for the calibration
+ // method). The result is displayed in the figure below as a 2D plot and also as the projection on the drift axis.
+ //
+ //Begin_Html
+ //<img src="TRD/clusterXerrorDiff2D.gif">
+ //End_Html
+ //
+ // Here is a list of uncertainty components:
+ // - Time Response Function (TRF) - the major contribution. since TRF is also not symmetric (even if tail is
+ // cancelled) it also creates a systematic shift dependent on the charge distribution before and after the cluster.
+ // - longitudinal diffusion - increase the width of TRF and scales with square root of drift length
+ // - variation in the drift velocity within the drift cell
+ //
+ // Author
+ // A.Bercuci <A.Bercuci@gsi.de>
+ //
+
if(tb<1 || tb>=24) return 10.; // return huge [10cm]
- const Double_t sx[24][10]={
+ static const Double_t sx[24][10]={
{0.000e+00, 9.352e-01, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 2.309e+00},
{8.387e-02, 8.718e-02, 8.816e-02, 9.444e-02, 9.993e-02, 1.083e-01, 1.161e-01, 1.280e-01, 1.417e-01, 1.406e-01},
{1.097e-01, 1.105e-01, 1.127e-01, 1.151e-01, 1.186e-01, 1.223e-01, 1.272e-01, 1.323e-01, 1.389e-01, 1.490e-01},
};
if(z>=0. && z<.25) return sx[tb][Int_t(z/.025)];
- Double_t m = 1.e-8; for(Int_t id=10; id--;) if(sx[tb][id]>m) m=sx[tb][id];
- return m;
+ Double_t m = 0.; for(Int_t id=10; id--;) m+=sx[tb][id];
+ return m*.1;
+
}
//___________________________________________________________________________
-Double_t AliTRDcluster::GetSY(Int_t tb, Double_t z)
+Double_t AliTRDcluster::GetSYdrift(Int_t tb, Int_t ly, Double_t/* z*/)
{
+ //
+ // Returns the error parameterization for TRD clusters as function of the drift length (here calibrated time bin tb)
+ // and optionally distance to anode wire (z) for the LUT r-phi cluster shape. By default (no z information) the largest
+ // value over all cluster to wire values is chosen.
+ //
+ // For the LUT method the dependence of s_y with x and d is obtained via a fit to the cluster to MC
+ // resolution. (see class AliTRDclusterResolution for more details). A normalization to the reference radial position
+ // x0 = 0.675 (tb=5 for ideal vd) is also applied (see GetSYprf()). The function is *NOT* calibration aware !
+ // The result is displayed in the figure below as a 2D plot and also as the projection on the drift axis. A comparison
+ // with the GAUS parameterization is also given
+ //
+ // For the GAUS method the dependence of s_y with x is *analytic* and it is expressed by the relation.
+ // BEGIN_LATEX
+ // #sigma^{2}_{y} = #sigma^{2}_{PRF} + #frac{x#delta_{t}^{2}}{(1+tg(#alpha_{L}))^{2}}
+ // END_LATEX
+ // The result is displayed in the figure below as function of the drift time and compared with the LUT parameterization.
+ //Begin_Html
+ //<img src="TRD/clusterYerrorDiff2D.gif">
+ //<img src="TRD/clusterYerrorDiff1D.gif">
+ //End_Html
+ //
+ // Author
+ // A.Bercuci <A.Bercuci@gsi.de>
+ //
+
if(tb<1 || tb>=24) return 10.; // return huge [10cm]
- const Double_t sy[24][10]={
+ static const Float_t lSy[6][24] = {
+ {75.7561, 0.0325, 0.0175, 0.0174, 0.0206, 0.0232,
+ 0.0253, 0.0262, 0.0265, 0.0264, 0.0266, 0.0257,
+ 0.0258, 0.0261, 0.0259, 0.0253, 0.0257, 0.0261,
+ 0.0255, 0.0250, 0.0259, 0.0266, 0.0278, 0.0319
+ },
+ {49.2252, 0.0371, 0.0204, 0.0189, 0.0230, 0.0261,
+ 0.0281, 0.0290, 0.0292, 0.0286, 0.0277, 0.0279,
+ 0.0285, 0.0281, 0.0291, 0.0281, 0.0281, 0.0282,
+ 0.0272, 0.0282, 0.0282, 0.0284, 0.0310, 0.0334
+ },
+ {55.1674, 0.0388, 0.0212, 0.0200, 0.0239, 0.0271,
+ 0.0288, 0.0299, 0.0306, 0.0300, 0.0296, 0.0303,
+ 0.0293, 0.0290, 0.0291, 0.0294, 0.0295, 0.0290,
+ 0.0293, 0.0292, 0.0292, 0.0293, 0.0316, 0.0358
+ },
+ {45.1004, 0.0411, 0.0225, 0.0215, 0.0249, 0.0281,
+ 0.0301, 0.0315, 0.0320, 0.0308, 0.0318, 0.0321,
+ 0.0312, 0.0311, 0.0316, 0.0315, 0.0310, 0.0308,
+ 0.0313, 0.0303, 0.0314, 0.0314, 0.0324, 0.0369
+ },
+ {43.8614, 0.0420, 0.0239, 0.0224, 0.0268, 0.0296,
+ 0.0322, 0.0336, 0.0333, 0.0326, 0.0321, 0.0325,
+ 0.0329, 0.0326, 0.0323, 0.0322, 0.0326, 0.0320,
+ 0.0329, 0.0319, 0.0314, 0.0329, 0.0341, 0.0373
+ },
+ {40.5440, 0.0434, 0.0246, 0.0236, 0.0275, 0.0311,
+ 0.0332, 0.0345, 0.0347, 0.0347, 0.0340, 0.0336,
+ 0.0339, 0.0344, 0.0339, 0.0341, 0.0341, 0.0342,
+ 0.0345, 0.0328, 0.0341, 0.0332, 0.0356, 0.0398
+ },
+ };
+ // adjusted ...
+ return TMath::Max(lSy[ly][tb]-0.0150, 0.0010);
+
+/* const Double_t sy[24][10]={
{0.000e+00, 2.610e-01, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 4.680e-01},
{3.019e-02, 3.036e-02, 3.131e-02, 3.203e-02, 3.294e-02, 3.407e-02, 3.555e-02, 3.682e-02, 3.766e-02, 3.824e-02},
{1.773e-02, 1.778e-02, 1.772e-02, 1.790e-02, 1.807e-02, 1.833e-02, 1.873e-02, 1.905e-02, 1.958e-02, 2.029e-02},
{2.812e-02, 2.786e-02, 2.776e-02, 2.723e-02, 2.695e-02, 2.650e-02, 2.642e-02, 2.617e-02, 2.612e-02, 2.610e-02},
{3.251e-02, 3.267e-02, 3.223e-02, 3.183e-02, 3.125e-02, 3.106e-02, 3.067e-02, 3.010e-02, 2.936e-02, 2.927e-02}
};
- if(z>=0. && z<.25) return sy[tb][Int_t(z/.025)];
+ if(z>=0. && z<.25) return sy[tb][Int_t(z/.025)] - sy[5][Int_t(z/.025)];
- Double_t m = 1.e-8; for(Int_t id=10; id--;) if(sy[tb][id]>m) m=sy[tb][id];
+ Double_t m = -1.e8; for(Int_t id=10; id--;) if((sy[tb][id] - sy[5][id])>m) m=sy[tb][id]-sy[5][id];
- return m;
+ return m;*/
}
+//___________________________________________________________________________
+Double_t AliTRDcluster::GetSYcharge(Float_t q)
+{
+ //
+ // Parameterization of the r-phi resolution component due to cluster charge.
+ // The value is the offset from the nominal cluster resolution defined as the
+ // cluster resolution at average cluster charge (q0).
+ //
+ // BEGIN_LATEX
+ // #Delta #sigma_{y}(q) = a*(#frac{1}{q} - #frac{1}{q_{0}})
+ // q_{0} #approx 50
+ // END_LATEX
+ // The definition is *NOT* robust against gain fluctuations and thus two approaches are possible
+ // when residual miscalibration are available:
+ // - determine parameterization with a resolution matching those of the gain
+ // - define an analytic model which scales with the gain.
+ //
+ // For more details please see AliTRDclusterResolution::ProcessCharge()
+ //
+ //Begin_Html
+ //<img src="TRD/clusterQerror.gif">
+ //End_Html
+ //
+ // Author
+ // A.Bercuci <A.Bercuci@gsi.de>
+ //
+
+ const Float_t sq0inv = 0.019962; // [1/q0]
+ const Float_t sqb = 0.037328; // [cm]
+
+ return sqb*(1./q - sq0inv);
+}
+
+//___________________________________________________________________________
+Double_t AliTRDcluster::GetSYprf(Int_t ly, Double_t center, Double_t s2)
+{
+ //
+ // Parameterization of the cluster error in the r-phi direction due to charge sharing between
+ // adiacent pads. Should be identical to what is provided in the OCDB as PRF [TODO]
+ //
+ // The parameterization is obtained from fitting cluster resolution at phi=exb and |x-0.675|<0.225.
+ // For more details see AliTRDclusterResolution::ProcessCenter().
+ //
+ //Begin_Html
+ //<img src="TRD/clusterPRFerror.gif">
+ //End_Html
+ //
+ // Author
+ // A.Bercuci <A.Bercuci@gsi.de>
+ //
+
+/* const Float_t scy[AliTRDgeometry::kNlayer][4] = {
+ {2.827e-02, 9.600e-04, 4.296e-01, 2.271e-02},
+ {2.952e-02,-2.198e-04, 4.146e-01, 2.339e-02},
+ {3.090e-02, 1.514e-03, 4.020e-01, 2.402e-02},
+ {3.260e-02,-2.037e-03, 3.946e-01, 2.509e-02},
+ {3.439e-02,-3.601e-04, 3.883e-01, 2.623e-02},
+ {3.510e-02, 2.066e-03, 3.651e-01, 2.588e-02},
+ };*/
+ const Float_t lPRF[] = {0.438, 0.403, 0.393, 0.382, 0.376, 0.345};
+
+ return s2*TMath::Gaus(center, 0., lPRF[ly]);
+}
+
+
//___________________________________________________________________________
Double_t AliTRDcluster::GetXcorr(Int_t tb, Double_t z)
{
- // drift length correction [cm]
- // TODO to be parametrized in term of drift velocity
+ //
+ // Drift length correction [cm]. Due to variation of mean drift velocity along the drift region
+ // from nominal vd at xd->infinity. For drift velocity determination based on tracking information
+ // the correction should be negligible.
+ //Begin_Html
+ //<img src="TRD/clusterXcorr.gif">
+ //End_Html
+ // TODO to be parametrized in term of drift velocity at infinite drift length
// A.Bercuci (Mar 28 2009)
+ //
if(tb<0 || tb>=24) return 0.;
const Int_t nd = 5;
- const Double_t dx[24][nd]={
+ static const Double_t dx[24][nd]={
{+1.747e-01,+3.195e-01,+1.641e-01,+1.607e-01,+6.002e-01},
{+5.468e-02,+5.760e-02,+6.365e-02,+8.003e-02,+1.067e-01},
{-6.327e-02,-6.339e-02,-6.423e-02,-6.900e-02,-7.949e-02},
//___________________________________________________________________________
Double_t AliTRDcluster::GetYcorr(Int_t ly, Float_t y)
{
-// PRF correction TODO to be replaced by the gaussian
-// approximation with full error parametrization
- const Float_t cy[AliTRDgeometry::kNlayer][3] = {
+ //
+ // PRF correction for the LUT r-phi cluster shape.
+ //Begin_Html
+ //<img src="TRD/clusterYcorr.gif">
+ //End_Html
+ //
+
+ static const Float_t cy[AliTRDgeometry::kNlayer][3] = {
{ 4.014e-04, 8.605e-03, -6.880e+00},
{-3.061e-04, 9.663e-03, -6.789e+00},
{ 1.124e-03, 1.105e-02, -6.825e+00},
}
//_____________________________________________________________________________
-Float_t AliTRDcluster::GetXloc(Double_t t0, Double_t vd, Double_t *const /*q*/, Double_t *const /*xq*/, Double_t /*z*/)
+Float_t AliTRDcluster::GetXloc(Double_t t0, Double_t vd
+ , const Double_t *const /*q*/
+ , const Double_t *const /*xq*/
+ , Double_t /*z*/)
{
-//
-// (Re)Calculate cluster position in the x direction in local chamber coordinates (with respect to the anode wire
-// position) using all available information from tracking.
-// Input parameters:
-// t0 - calibration aware trigger delay [us]
-// vd - drift velocity in the region of the cluster [cm/us]
-// z - distance to the anode wire [cm]. By default 0.2 !!
-// q & xq - array of charges and cluster positions from previous clusters in the tracklet [a.u.]
-// Output values :
-// return x position of the cluster with respect to the
-// anode wire using all tracking information
-//
-// The estimation of the radial position is based on calculating the drift time and the drift velocity at the point of
-// estimation. The drift time can be estimated according to the expression:
-// BEGIN_LATEX
-// t_{drift} = t_{bin} - t_{0} - t_{cause}(x) - t_{TC}(q_{i-1}, q_{i-2}, ...)
-// END_LATEX
-// where t_0 is the delay of the trigger signal. t_cause is the causality delay between ionisation electrons hitting
-// the anode and the registration of maximum signal by the electronics - it is due to the rising time of the TRF
-// convoluted with the diffusion width. t_TC is the residual charge from previous bins due to residual tails after tail
-// cancellation.
-//
-// The drift velocity is considered to vary linearly with the drift length (independent of the distance to the anode wire
-// in the z direction). Thus one can write the calculate iteratively the drift length from the expression:
-// BEGIN_LATEX
-// x = t_{drift}(x)*v_{drfit}(x)
-// END_LATEX
-//
-// Authors
-// Alex Bercuci <A.Bercuci@gsi.de>
-//
+ //
+ // (Re)Calculate cluster position in the x direction in local chamber coordinates (with respect to the anode wire
+ // position) using all available information from tracking.
+ // Input parameters:
+ // t0 - calibration aware trigger delay [us]
+ // vd - drift velocity in the region of the cluster [cm/us]
+ // z - distance to the anode wire [cm]. By default average over the drift cell width.
+ // q & xq - array of charges and cluster positions from previous clusters in the tracklet [a.u.]
+ // Output values :
+ // return x position of the cluster with respect to the
+ // anode wire using all tracking information
+ //
+ // The estimation of the radial position is based on calculating the drift time and the drift velocity at the point of
+ // estimation. The drift time can be estimated according to the expression:
+ // BEGIN_LATEX
+ // t_{drift} = t_{bin} - t_{0} - t_{cause}(x) - t_{TC}(q_{i-1}, q_{i-2}, ...)
+ // END_LATEX
+ // where t_0 is the delay of the trigger signal. t_cause is the causality delay between ionisation electrons hitting
+ // the anode and the registration of maximum signal by the electronics - it is due to the rising time of the TRF
+ // A second order correction here comes from the fact that the time spreading of charge at anode is the convolution of
+ // TRF with the diffusion and thus cross-talk between clusters before and after local clusters changes with drift length.
+ // t_TC is the residual charge from previous (in time) clusters due to residual tails after tail cancellation.
+ // This tends to push cluster forward and depends on the magnitude of their charge.
+ //
+ // The drift velocity varies with the drift length (and distance to anode wire) as described by cell structure simulation.
+ // Thus one, in principle, can calculate iteratively the drift length from the expression:
+ // BEGIN_LATEX
+ // x = t_{drift}(x)*v_{drift}(x)
+ // END_LATEX
+ // In practice we use a numerical approach (AliTRDcluster::GetXcorr()) to correct for anisochronity obtained from MC
+ // comparison (see AliTRDclusterResolution::ProcessSigma()). Also the calibration of 0 approximation (no x dependence)
+ // for t_cause is obtained from MC comparisons and impossible to disentangle in real life from trigger delay.
+ //
+ // Author
+ // Alex Bercuci <A.Bercuci@gsi.de>
+ //
AliTRDCommonParam *cp = AliTRDCommonParam::Instance();
Double_t fFreq = cp->GetSamplingFrequency();
- // calculate t0 corrected time bin
- Double_t td = fPadTime - t0;
- fLocalTimeBin = TMath::Nint(td);
//drift time corresponding to the center of the time bin
- td = (td + .5)/fFreq; // [us]
+ Double_t td = (fPadTime + .5)/fFreq; // [us]
// correction for t0
td -= t0;
- // calculate radial posion of clusters in the drift region
+ // time bin corrected for t0
+ // Bug in TMath::Nint().root-5.23.02
+ // TMath::Nint(3.5) = 4 and TMath::Nint(4.5) = 4
+ Double_t tmp = td*fFreq;
+ fLocalTimeBin = Char_t(TMath::Floor(tmp));
+ if(tmp-fLocalTimeBin > .5) fLocalTimeBin++;
if(td < .2) return 0.;
// TRF rising time (fitted)
// It should be absorbed by the t0. For the moment t0 is 0 for simulations.
td -= 0.189;
// apply fitted correction
- Float_t x = td*vd + GetXcorr(fLocalTimeBin);
+ Float_t x = td*vd + (HasXcorr() ? GetXcorr(fLocalTimeBin) : 0.);
if(x>0.&&x<.5*AliTRDgeometry::CamHght()+AliTRDgeometry::CdrHght()) SetInChamber();
return x;
-
-/*
- // invert drift time function
- Double_t xM= AliTRDgeometry::CamHght()+AliTRDgeometry::CdrHght(),
- x = vd*td + .5*AliTRDgeometry::CamHght(),
- t = cp->TimeStruct(vd, x, z), dx1=0.,dx2;
- while(TMath::Abs(td-t)>1.e-4){ // convergence on 100ps
- dx2 = vd*(td-t);
- if(TMath::Abs(TMath::Abs(dx2)-TMath::Abs(dx1))<1.e-6){
- x+=.5*dx2;
- break;
- } else x+=dx2;
-
- if(x<0. || x>xM) return 0.;
- t = cp->TimeStruct(vd, x, z);
- dx1 = dx2;
- }
-
- return x-.5*AliTRDgeometry::CamHght();
-*/
}
//_____________________________________________________________________________
-Float_t AliTRDcluster::GetYloc(Double_t y0, Double_t s2, Double_t W, Double_t *const y1, Double_t *const y2)
+Float_t AliTRDcluster::GetYloc(Double_t y0, Double_t s2, Double_t W
+ , Double_t *const y1, Double_t *const y2)
{
+ //
+ // Calculate, in tracking cooordinate system, the r-phi offset the cluster
+ // from the middle of the center pad. Three possible methods are implemented:
+ // - Center of Gravity (COG) see AliTRDcluster::GetDYcog()
+ // - Look-up Table (LUT) see AliTRDcluster::GetDYlut()
+ // - Gauss shape (GAUS) see AliTRDcluster::GetDYgauss()
+ // In addition for the case of LUT method position corrections are also
+ // applied (see AliTRDcluster::GetYcorr())
+ //
- //printf(" s[%3d %3d %3d] w[%f %f] yr[%f %f]\n", fSignals[2], fSignals[3], fSignals[4], w1/(w1+w2), w2/(w1+w2), y1r*W, y2r*W);
if(IsRPhiMethod(kCOG)) GetDYcog();
else if(IsRPhiMethod(kLUT)) GetDYlut();
- if(IsRPhiMethod(kGAUS)) GetDYgauss(s2/W/W, y1, y2);
+ else if(IsRPhiMethod(kGAUS)) GetDYgauss(s2/W/W, y1, y2);
+ else return 0.;
if(y1) (*y1)*=W;
if(y2) (*y2)*=W;
- return y0-fCenter*W;
+ return y0+fCenter*W+(IsRPhiMethod(kLUT)?GetYcorr(AliTRDgeometry::GetLayer(fDetector), fCenter):0.);
+}
+
+//___________________________________________________________________________
+void AliTRDcluster::SetSigmaY2(Float_t s2, Float_t dt, Float_t exb, Float_t x, Float_t z, Float_t tgp)
+{
+ //
+ // Set variance of TRD cluster in the r-phi direction for each method.
+ // Parameters :
+ // - s2 - variance due to PRF width for the case of Gauss model. Replaced by parameterization in case of LUT.
+ // - dt - transversal diffusion coeficient
+ // - exb - tg of lorentz angle
+ // - x - drift length - with respect to the anode wire
+ // - z - offset from the anode wire
+ // - tgp - local tangent of the track momentum azimuthal angle
+ //
+ // The ingredients from which the error is computed are:
+ // - PRF (charge sharing on adjacent pads) - see AliTRDcluster::GetSYprf()
+ // - diffusion (dependence with drift length and [2nd order] distance to anode wire) - see AliTRDcluster::GetSYdrift()
+ // - charge of the cluster (complex dependence on gain and tail cancellation) - see AliTRDcluster::GetSYcharge()
+ // - lorentz angle (dependence on the drift length and [2nd order] distance to anode wire) - see AliTRDcluster::GetSX()
+ // - track angle (superposition of charges on the anode wire) - see AliTRDseedV1::Fit()
+ // - projection of radial(x) error on r-phi due to fixed value assumed in tracking for x - see AliTRDseedV1::Fit()
+ //
+ // The last 2 contributions to cluster error can be estimated only during tracking when the track angle
+ // is known (tgp). For this reason the errors (and optional position) of TRD clusters are recalculated during
+ // tracking and thus clusters attached to tracks might differ from bare clusters.
+ //
+ // Taking into account all contributions one can write the the TRD cluster error parameterization as:
+ // BEGIN_LATEX
+ // #sigma_{y}^{2} = (#sigma_{diff}*Gauss(0, s_{ly}) + #delta_{#sigma}(q))^{2} + tg^{2}(#alpha_{L})*#sigma_{x}^{2} + tg^{2}(#phi-#alpha_{L})*#sigma_{x}^{2}+[tg(#phi-#alpha_{L})*tg(#alpha_{L})*x]^{2}/12
+ // END_LATEX
+ // From this formula one can deduce a that the simplest calibration method for PRF and diffusion contributions is
+ // by measuring resolution at B=0T and phi=0. To disentangle further the two remaining contributions one has
+ // to represent s2 as a function of drift length.
+ //
+ // In the gaussian model the diffusion contribution can be expressed as:
+ // BEGIN_LATEX
+ // #sigma^{2}_{y} = #sigma^{2}_{PRF} + #frac{x#delta_{t}^{2}}{(1+tg(#alpha_{L}))^{2}}
+ // END_LATEX
+ // thus resulting the PRF contribution. For the case of the LUT model both contributions have to be determined from
+ // the fit (see AliTRDclusterResolution::ProcessCenter() for details).
+ //
+ // Author:
+ // A.Bercuci <A.Bercuci@gsi.de>
+ //
+
+ Float_t sigmaY2 = 0.;
+ Int_t ly = AliTRDgeometry::GetLayer(fDetector);
+ if(IsRPhiMethod(kCOG)) sigmaY2 = 4.e-4;
+ else if(IsRPhiMethod(kLUT)){
+ Float_t sd = GetSYdrift(fLocalTimeBin, ly, z); //printf("drift[%6.2f] ", 1.e4*sd);
+ sigmaY2 = GetSYprf(ly, fCenter, sd); //printf("PRF[%6.2f] ", 1.e4*sigmaY2);
+ // add charge contribution TODO scale with respect to s2
+ sigmaY2+= GetSYcharge(TMath::Abs(fQ)); //printf("Q[%6.2f] ", 1.e4*sigmaY2);
+ sigmaY2 = TMath::Max(sigmaY2, Float_t(0.0010)); //!! protection
+ sigmaY2*= sigmaY2;
+ } else if(IsRPhiMethod(kGAUS)){
+ // PRF contribution
+ sigmaY2 = s2;
+ // Diffusion contribution
+ Double_t sD2 = dt/(1.+exb); sD2 *= sD2; sD2 *= x;
+ sigmaY2+= sD2;
+ // add charge contribution TODO scale with respect to s2
+ //sigmaY2+= GetSYcharge(TMath::Abs(fQ));
+ }
+
+ // store tg^2(phi-a_L) and tg^2(a_L)
+ // limit parametrization to a maximum angle of 25 deg
+ if(TMath::Abs(tgp)>0.466) tgp = (tgp>0.)?0.466:-0.466;
+ Double_t tgg = (tgp-exb)/(1.+tgp*exb); tgg *= tgg;
+ Double_t exb2= exb*exb;
+
+ // Lorentz angle shift contribution
+ Float_t sx = GetSX(fLocalTimeBin, z); sx*=sx;
+ sigmaY2+= exb2*sx; //printf("Al[%6.2f] ", 1.e4*TMath::Sqrt(sigmaY2));
+
+ // Radial contribution due to not measuring x in Kalman model
+ sigmaY2+= tgg*sx; //printf("x[%6.2f] ", 1.e4*TMath::Sqrt(sigmaY2));
+
+ // Track angle contribution
+ sigmaY2+= tgg*x*x*exb2/12.; //printf("angle[%6.2f]\n", 1.e4*TMath::Sqrt(sigmaY2));
+
+ AliCluster::SetSigmaY2(sigmaY2);
+
}
//_____________________________________________________________________________
if ( IsUsed() != inCluster->IsUsed() ) return kFALSE;
return kTRUE;
+
}
//_____________________________________________________________________________
void AliTRDcluster::Print(Option_t *o) const
{
- AliInfo(Form("Det[%3d] LTrC[%+6.2f %+6.2f %+6.2f] Q[%5.1f] Stat[in(%c) use(%c) sh(%c)]",
- fDetector, GetX(), GetY(), GetZ(), fQ,
- IsInChamber() ? 'y' : 'n', IsUsed() ? 'y' : 'n', IsShared() ? 'y' : 'n'));
+ //
+ // Print cluster information
+ //
- if(strcmp(o, "a")!=0) return;
- AliInfo(Form("LChC[c(%3d) r(%2d) t(%2d)] t-t0[%2d] Npad[%d] cen[%5.3f] mask[%d]", fPadCol, fPadRow, fPadTime, fLocalTimeBin, fNPads, fCenter, fClusterMasking));
- AliInfo(Form("Signals[%3d %3d %3d %3d %3d %3d %3d]", fSignals[0], fSignals[1], fSignals[2], fSignals[3], fSignals[4], fSignals[5], fSignals[6]));
+ if(strcmp(o, "a")==0) {
+ AliInfo(Form(
+ "\nDet[%3d] LTrC[%+6.2f %+6.2f %+6.2f] Q[%5.1f] FLAG[in(%c) use(%c) sh(%c)] Y[%s]"
+ "\n LChC[c(%3d) r(%2d) t(%2d)] t-t0[%2d] Npad[%d] cen[%5.3f] mask[%d]"
+ "\n QS[%3d %3d %3d %3d %3d %3d %3d] S2[%e %e]"
+ , fDetector, GetX(), GetY(), GetZ(), fQ,
+ IsInChamber() ? 'y' : 'n',
+ IsUsed() ? 'y' : 'n',
+ IsShared() ? 'y' : 'n',
+ IsRPhiMethod(kGAUS)?"GAUS":(IsRPhiMethod(kLUT)?"LUT":"COG")
+ , fPadCol, fPadRow, fPadTime, fLocalTimeBin, fNPads, fCenter, fClusterMasking
+ , fSignals[0], fSignals[1], fSignals[2], fSignals[3]
+ , fSignals[4], fSignals[5], fSignals[6]
+ , GetSigmaY2(), GetSigmaZ2()));
+ } else {
+ AliInfo(Form("Det[%3d] LTrC[%+6.2f %+6.2f %+6.2f] Q[%5.1f] FLAG[in(%c) use(%c) sh(%c)] Y[%s]",
+ fDetector, GetX(), GetY(), GetZ(), fQ,
+ IsInChamber() ? 'y' : 'n',
+ IsUsed() ? 'y' : 'n',
+ IsShared() ? 'y' : 'n',
+ IsRPhiMethod(kGAUS)?"GAUS":(IsRPhiMethod(kLUT)?"LUT":"COG")
+ ));
+ }
}
-
//_____________________________________________________________________________
void AliTRDcluster::SetPadMaskedPosition(UChar_t position)
{
//
- // store the pad corruption position code
+ // Store the pad corruption position code
//
// Code: 1 = left cluster
// 2 = middle cluster;
// 4 = right cluster
//
- for(Int_t ipos = 0; ipos < 3; ipos++)
- if(TESTBIT(position, ipos))
+
+ for (Int_t ipos = 0; ipos < 3; ipos++) {
+ if (TESTBIT(position, ipos))
SETBIT(fClusterMasking, ipos);
+ }
}
//_____________________________________________________________________________
void AliTRDcluster::SetPadMaskedStatus(UChar_t status)
{
//
- // store the status of the corrupted pad
+ // Store the status of the corrupted pad
//
// Code: 2 = noisy
// 4 = Bridged Left
// 8 = Bridged Right
// 32 = Not Connected
- for(Int_t ipos = 0; ipos < 5; ipos++)
+ //
+
+ for (Int_t ipos = 0; ipos < 5; ipos++) {
if(TESTBIT(status, ipos))
SETBIT(fClusterMasking, ipos + 3);
+ }
+
}
//___________________________________________________________________________
-Float_t AliTRDcluster::GetDYcog(Double_t *const, Double_t *const)
+Float_t AliTRDcluster::GetDYcog(const Double_t *const, const Double_t *const)
{
-//
-// Get COG position
-// Used for clusters with more than 3 pads - where LUT not applicable
-//
+ //
+ // Get COG position
+ // Used for clusters with more than 3 pads - where LUT not applicable
+ //
Double_t sum = fSignals[1]
+fSignals[2]
// Go to 3 pad COG ????
// ???????????? CBL
fCenter = (0.0 * (-fSignals[1] + fSignals[5])
- + (-fSignals[2] + fSignals[4])) / sum;
+ + (-fSignals[2] + fSignals[4])) / sum;
return fCenter;
}
//___________________________________________________________________________
-Float_t AliTRDcluster::GetDYlut(Double_t *const, Double_t *const)
+Float_t AliTRDcluster::GetDYlut(const Double_t *const, const Double_t *const)
{
//
// Calculates the cluster position using the lookup table.
// Alex Bercuci <A.Bercuci@gsi.de>
// Theodor Rascanu <trascanu@stud.uni-frankfurt.de>
//
- Double_t w1 = fSignals[2]*fSignals[2];
- Double_t w2 = fSignals[4]*fSignals[4];
+ Double_t w1 = fSignals[2]*fSignals[2];
+ Double_t w2 = fSignals[4]*fSignals[4];
+ Double_t w = w1+w2;
+ if(w<1.){
+ AliError("Missing side signals for cluster.");
+ Print("a");
+ return 0.;
+ }
+
//Double_t s2w = s2/W/W;
Float_t y1r = fSignals[2]>0 ? (-0.5 + s2w*TMath::Log(fSignals[3]/(Float_t)fSignals[2])) : 0.;
Float_t y2r = fSignals[4]>0 ? (0.5 + s2w*TMath::Log(fSignals[4]/(Float_t)fSignals[3])) : 0.;
if(y1) (*y1) = y1r;
if(y2) (*y2) = y2r;
- return fCenter = (w1*y1r+w2*y2r)/(w1+w2);
+ return fCenter = (w1*y1r+w2*y2r)/w;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff