Line data Source code
1 : /**************************************************************************
2 : * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 : * *
4 : * Author: The ALICE Off-line Project. *
5 : * Contributors are mentioned in the code where appropriate. *
6 : * *
7 : * Permission to use, copy, modify and distribute this software and its *
8 : * documentation strictly for non-commercial purposes is hereby granted *
9 : * without fee, provided that the above copyright notice appears in all *
10 : * copies and that both the copyright notice and this permission notice *
11 : * appear in the supporting documentation. The authors make no claims *
12 : * about the suitability of this software for any purpose. It is *
13 : * provided "as is" without express or implied warranty. *
14 : **************************************************************************/
15 :
16 : /// \class AliTPCExBBShape
17 : /// \brief AliTPCExBBShape class
18 :
19 : #include <AliMagF.h>
20 : #include "TGeoGlobalMagField.h"
21 : #include "AliTPCcalibDB.h"
22 : #include "AliTPCParam.h"
23 : #include "AliLog.h"
24 :
25 : #include "AliTPCExBBShape.h"
26 :
27 : AliTPCExBBShape::AliTPCExBBShape()
28 3 : : AliTPCCorrection("exb_bshape","ExB B-shape"),
29 3 : fC1(0.),fC2(0.),
30 3 : fScaling(1.),
31 3 : fBField(0)
32 15 : {
33 : /// default constructor
34 :
35 6 : }
36 :
37 0 : AliTPCExBBShape::~AliTPCExBBShape() {
38 : /// virtual destructor
39 :
40 0 : }
41 :
42 :
43 :
44 :
45 : Bool_t AliTPCExBBShape::AddCorrectionCompact(AliTPCCorrection* corr, Double_t weight){
46 : /// Add correction and make them compact
47 : /// Assumptions:
48 : /// - origin of distortion/correction are additive
49 : /// - only correction ot the same type supported ()
50 :
51 0 : if (corr==NULL) {
52 0 : AliError("Zerro pointer - correction");
53 0 : return kFALSE;
54 : }
55 0 : AliTPCExBBShape* corrC = dynamic_cast<AliTPCExBBShape *>(corr);
56 0 : if (corrC == NULL) {
57 0 : AliError(TString::Format("Inconsistent class types: %s\%s",IsA()->GetName(),corr->IsA()->GetName()).Data());
58 0 : return kFALSE;
59 : }
60 0 : fScaling= weight;
61 : //
62 0 : return kTRUE;
63 0 : }
64 :
65 :
66 : void AliTPCExBBShape::Init() {
67 : /// Initialization funtion
68 :
69 18 : AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
70 9 : if (!magF) AliError("Magneticd field - not initialized");
71 9 : Double_t bzField = magF->SolenoidField()/10.; //field in T
72 9 : SetBField(magF);
73 9 : AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
74 9 : if (!param) AliError("Parameters - not initialized");
75 9 : Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
76 : Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
77 9 : Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
78 : // Correction Terms for effective omegaTau; obtained by a laser calibration run
79 9 : SetOmegaTauT1T2(wt,fT1,fT2);
80 :
81 :
82 9 : }
83 :
84 : void AliTPCExBBShape::Update(const TTimeStamp &/*timeStamp*/) {
85 : /// Update function
86 :
87 0 : AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
88 0 : if (!magF) AliError("Magneticd field - not initialized");
89 0 : Double_t bzField = magF->SolenoidField()/10.; //field in T
90 0 : SetBField(magF);
91 0 : AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
92 0 : if (!param) AliError("Parameters - not initialized");
93 0 : Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
94 : Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
95 0 : Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
96 : // Correction Terms for effective omegaTau; obtained by a laser calibration run
97 0 : SetOmegaTauT1T2(wt,fT1,fT2);
98 :
99 :
100 0 : }
101 :
102 :
103 :
104 : void AliTPCExBBShape::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {
105 : /// Calculates the space point corrections of the B field inperfections (B field shape)
106 :
107 0 : if (!fBField) {
108 0 : for (Int_t j=0;j<3;++j) dx[j]=0.;
109 0 : return;
110 : }
111 :
112 0 : const Double_t xStart[3]={ x[0], x[1], x[2] };
113 0 : const Double_t xEnd[3]={ x[0], x[1], roc%36<18?fgkTPCZ0:-fgkTPCZ0 };
114 :
115 0 : Double_t intBStart[3];
116 0 : Double_t intBEnd[3];
117 :
118 0 : fBField->GetTPCRatInt(xStart,intBStart);
119 0 : fBField->GetTPCRatInt(xEnd, intBEnd );
120 :
121 0 : const Float_t intBxOverBz=fScaling*(intBEnd[0]-intBStart[0]);
122 0 : const Float_t intByOverBz=fScaling*(intBEnd[1]-intBStart[1]);
123 :
124 0 : dx[0]=fC2*intBxOverBz-fC1*intByOverBz;
125 0 : dx[1]=fC1*intBxOverBz+fC2*intByOverBz;
126 0 : dx[2]=0.;
127 :
128 :
129 0 : }
130 :
131 : void AliTPCExBBShape::GetBxAndByOverBz(const Float_t x[],const Short_t roc,Float_t BxByOverBz[]) {
132 : /// This function is purely for calibration purposes
133 : /// Returns the via AliMagF obtaind B field integrals
134 :
135 0 : if (!fBField) {
136 0 : for (Int_t j=0;j<3;++j) BxByOverBz[j]=0.;
137 0 : return;
138 : }
139 :
140 0 : const Double_t xStart[3]={ x[0], x[1], x[2] };
141 0 : const Double_t xEnd[3]={ x[0], x[1], roc%36<18?fgkTPCZ0:-fgkTPCZ0 };
142 :
143 0 : Double_t intBStart[3];
144 0 : Double_t intBEnd[3];
145 :
146 0 : fBField->GetTPCRatInt(xStart,intBStart);
147 0 : fBField->GetTPCRatInt(xEnd, intBEnd );
148 :
149 0 : const Float_t intBxOverBz=fScaling*(intBEnd[0]-intBStart[0]);
150 0 : const Float_t intByOverBz=fScaling*(intBEnd[1]-intBStart[1]);
151 :
152 0 : BxByOverBz[0]=intBxOverBz;
153 0 : BxByOverBz[1]=intByOverBz;
154 :
155 0 : }
156 :
157 : void AliTPCExBBShape::Print(Option_t* option) const {
158 : /// Print function to check the settings (e.g. voltage offsets)
159 : /// option=="a" prints details of the B field settings and the
160 : /// C0 and C1 coefficents (for calibration purposes)
161 :
162 0 : TString opt = option; opt.ToLower();
163 0 : printf("%s\t%s\n - B field settings:\n",GetTitle(),GetName());
164 0 : fBField->Print(option);
165 : // printf(" - B field: X-Twist: %1.5lf rad, Y-Twist: %1.5lf rad \n",fBField->Print(option));
166 0 : if (opt.Contains("a")) { // Print all details
167 0 : printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2);
168 0 : printf(" - C1: %1.4f, C2: %1.4f \n",fC1,fC2);
169 : }
170 0 : }
171 :
172 : Double_t AliTPCExBBShape::GetBFieldXYZ(Double_t gx, Double_t gy, Double_t gz, Int_t axisType){
173 : /// return B field at given x,y,z
174 :
175 0 : AliMagF* field = (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
176 0 : if (!field) return 0;
177 0 : Double_t xyz[3]={gx,gy,gz};
178 0 : Double_t bxyz[3]={0};
179 0 : field->Field(xyz,bxyz);
180 : //
181 0 : Double_t r=TMath::Sqrt(gx*gx+gy*gy);
182 : // Double_t b=TMath::Sqrt(bxyz[0]*bxyz[0]+bxyz[1]*bxyz[1]);
183 0 : if (axisType==0) {
184 0 : return (xyz[0]*bxyz[1]-xyz[1]*bxyz[0])/(bxyz[2]*r);
185 : }
186 0 : if (axisType==1){
187 0 : return (xyz[0]*bxyz[0]+xyz[1]*bxyz[1])/(bxyz[2]*r);
188 : }
189 0 : if (axisType==2) return bxyz[2];
190 0 : if (axisType==3) return bxyz[0];
191 0 : if (axisType==4) return bxyz[1];
192 0 : if (axisType==5) return bxyz[2];
193 : return bxyz[2];
194 0 : }
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