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4 * Author: The ALICE Off-line Project. *
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14 **************************************************************************/
16 /// \class AliTPCExBConical
18 /// Calculates the space point distortions due to the conical shape of ALICE TPC.
20 /// Becasue of mechanical deformation ALICE TPC, chambers are misaligned in z direction
21 /// TPC has roughly conical shape
23 /// For the moment ONLY efective correction used - NOT EDGE EFFECT calcualted
25 /// The class allows "effective Omega Tau" corrections.
30 /// AliTPCExBConical conical;
31 /// conical.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB
32 /// conical.SetXConical(0.001); // set conical in X direction (in rad)
33 /// // plot dRPhi distortions ...
34 /// conical.CreateHistoDRPhiinZR(1.,100,100)->Draw("surf2");
37 /// \author Marian Ivanov, Jim Thomas, Magnus Mager, Stefan Rossegger
41 #include "TGeoGlobalMagField.h"
42 #include "AliTPCcalibDB.h"
43 #include "AliTPCParam.h"
47 #include "AliTPCROC.h"
48 #include "AliTPCExBConical.h"
49 ClassImp(AliTPCExBConical)
51 AliTPCExBConical::AliTPCExBConical()
52 : AliTPCCorrection("exb_conical","ExB conical"),
53 fC1(0.),fC2(0.),fConicalFactor(0)
56 // default constructor
58 for (Int_t i=0; i<3; i++){
64 AliTPCExBConical::~AliTPCExBConical() {
65 /// default destructor
71 void AliTPCExBConical::Init() {
72 /// Initialization funtion
74 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
75 if (!magF) AliError("Magneticd field - not initialized");
76 Double_t bzField = magF->SolenoidField()/10.; ///< field in T
77 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
78 if (!param) AliError("Parameters - not initialized");
79 Double_t vdrift = param->GetDriftV()/1000000.; ///< [cm/us] // From dataBase: to be updated: per second (ideally)
80 Double_t ezField = 400; ///< [V/cm] // to be updated: never (hopefully)
81 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
82 // Correction Terms for effective omegaTau; obtained by a laser calibration run
83 SetOmegaTauT1T2(wt,fT1,fT2);
88 void AliTPCExBConical::Update(const TTimeStamp &/*timeStamp*/) {
91 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
92 if (!magF) AliError("Magneticd field - not initialized");
93 Double_t bzField = magF->SolenoidField()/10.; ///< field in T
94 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
95 if (!param) AliError("Parameters - not initialized");
96 Double_t vdrift = param->GetDriftV()/1000000.; ///< [cm/us] // From dataBase: to be updated: per second (ideally)
97 Double_t ezField = 400; ///< [V/cm] // to be updated: never (hopefully)
98 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
99 // Correction Terms for effective omegaTau; obtained by a laser calibration run
100 SetOmegaTauT1T2(wt,fT1,fT2);
107 void AliTPCExBConical::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {
108 /// Calculates the correction due conical shape
110 AliTPCROC * calROC = AliTPCROC::Instance();
111 const Double_t kRTPC0 =calROC->GetPadRowRadii(0,0);
112 const Double_t kRTPC1 =calROC->GetPadRowRadii(36,calROC->GetNRows(36)-1);
113 Float_t rmiddle=(kRTPC0+kRTPC1)/2.;
115 Double_t phi =TMath::ATan2(x[1],x[0]);
116 Double_t r =TMath::Sqrt(x[1]*x[1]+x[0]*x[0]);
118 if (roc%36<18) dTheta = fConicalA[0]+TMath::Cos(phi)*fConicalA[1]+TMath::Sin(phi)*fConicalA[2];
120 dTheta = fConicalC[0]+TMath::Cos(phi)*fConicalC[1]+TMath::Sin(phi)*fConicalC[2];
122 Double_t corr=dTheta*fConicalFactor;
123 if (roc%36>=18) corr*=-1.;
124 Double_t drphi=fC1*corr;
125 Double_t dr =fC2*corr;
126 dx[0]= TMath::Cos(phi)*dr-TMath::Sin(phi)*drphi;
127 dx[1]= TMath::Sin(phi)*dr+TMath::Cos(phi)*drphi;
128 dx[2]= -0.001*dTheta*(r-rmiddle); // dtheta in mrad
132 void AliTPCExBConical::Print(const Option_t* option) const {
133 /// Print function to check the settings (e.g. the conical in the X direction)
134 /// option=="a" prints the C0 and C1 coefficents for calibration purposes
136 TString opt = option; opt.ToLower();
137 printf("%s:%s\n",GetTitle(), GetName());
138 printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2);
139 printf("Conical settings: Empirical: %1.5f mm/mrad\n",fConicalFactor);
140 printf("Conical settings: A-Conical: %1.5f mrad:%1.5f mrad:%1.5f mrad \n",fConicalA[0],fConicalA[1],fConicalA[2]);
141 printf("Conical settings: C-Conical: %1.5f mrad:%1.5f mrad:%1.5f mrad \n",fConicalC[0],fConicalC[1],fConicalC[2]);
146 void AliTPCExBConical::SetConicalA(Float_t conicalA[3]){
147 /// set paramters of conical shape - A side - obtained from alignment
149 fConicalA[0]= conicalA[0]; // constant
150 fConicalA[1]= conicalA[1]; // cos
151 fConicalA[2]= conicalA[2]; // sin
153 void AliTPCExBConical::SetConicalC(Float_t conicalC[3]){
154 /// set paramters of conical shape -C side obtained form the alignemnt
156 fConicalC[0]= conicalC[0]; // constant
157 fConicalC[1]= conicalC[1]; // cos
158 fConicalC[2]= conicalC[2]; // sin