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ae425f91 | 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 | //////////////////////////////////////////////////////////////////////////// | |
17 | // // | |
18 | // AliTPCExBEffective class // | |
19 | // Correct for the rest of ExB effect which are not covered by physical models | |
20 | // | |
21 | // Motivation: | |
22 | // ExB correction: | |
602803b6 | 23 | // dr = c0* integral(Er/Ez) + c1* integral(Erphi/Ez) |
24 | // drphi = -c1* integral(Er/Ez) + c0* integral(Erphi/Ez) | |
ae425f91 | 25 | // Where: |
26 | // wt = Bz*(k*vdrift/E) ~ 0.3 at B=0.5 T | |
27 | // c0 = 1/(1+T2*T2*wt*wt) | |
28 | // c1 = T1*wt/(1+T1*T1*wt*wt) | |
29 | // | |
602803b6 | 30 | // Residual integral(Er/Ez,Erphi/Ez) obtained comparing the B field 0 and B field +-0.5 T setting |
ae425f91 | 31 | // minimizing track matching residuals |
602803b6 | 32 | // delta(Er/Ez) ~ sum[ poln(r) * polm(z) * cos(n,phi)] |
ae425f91 | 33 | // |
34 | //////////////////////////////////////////////////////////////////////////// | |
35 | #include "AliMagF.h" | |
36 | #include "TGeoGlobalMagField.h" | |
37 | #include "AliTPCcalibDB.h" | |
38 | #include "AliTPCParam.h" | |
39 | #include "AliLog.h" | |
40 | ||
41 | #include "TMath.h" | |
42 | #include "AliTPCROC.h" | |
43 | #include "AliTPCExBEffective.h" | |
44 | ClassImp(AliTPCExBEffective) | |
45 | ||
46 | AliTPCExBEffective::AliTPCExBEffective() | |
47 | : AliTPCCorrection("ExB_effective","ExB effective"), | |
48 | fC0(1.),fC1(0.), | |
49 | fPolynomA(0), | |
50 | fPolynomC(0), | |
51 | fPolynomValA(0), | |
52 | fPolynomValC(0) | |
53 | { | |
54 | // | |
55 | // default constructor | |
56 | // | |
57 | } | |
58 | ||
59 | AliTPCExBEffective::~AliTPCExBEffective() { | |
60 | // | |
61 | // default destructor | |
62 | // | |
63 | } | |
64 | ||
65 | ||
66 | ||
67 | void AliTPCExBEffective::Init() { | |
68 | // | |
69 | // Initialization funtion | |
70 | // | |
71 | ||
72 | AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField(); | |
73 | if (!magF) AliError("Magneticd field - not initialized"); | |
74 | Double_t bzField = magF->SolenoidField()/10.; //field in T | |
75 | AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters(); | |
76 | if (!param) AliError("Parameters - not initialized"); | |
77 | Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally) | |
78 | Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully) | |
79 | Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; | |
80 | // Correction Terms for effective omegaTau; obtained by a laser calibration run | |
81 | SetOmegaTauT1T2(wt,fT1,fT2); | |
82 | ||
83 | ||
84 | } | |
85 | ||
86 | void AliTPCExBEffective::Update(const TTimeStamp &/*timeStamp*/) { | |
87 | // | |
88 | // Update function | |
89 | // | |
90 | AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField(); | |
91 | if (!magF) AliError("Magneticd field - not initialized"); | |
92 | Double_t bzField = magF->SolenoidField()/10.; //field in T | |
93 | AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters(); | |
94 | if (!param) AliError("Parameters - not initialized"); | |
95 | Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally) | |
96 | Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully) | |
97 | Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; | |
98 | // Correction Terms for effective omegaTau; obtained by a laser calibration run | |
99 | SetOmegaTauT1T2(wt,fT1,fT2); | |
100 | ||
101 | ||
102 | } | |
103 | ||
104 | ||
105 | ||
106 | void AliTPCExBEffective::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) { | |
107 | // | |
108 | // Calculates the correction due conical shape | |
109 | // | |
110 | if (!fPolynomA) return; | |
111 | AliTPCROC * calROC = AliTPCROC::Instance(); | |
112 | const Double_t kRTPC0 =calROC->GetPadRowRadii(0,0); | |
113 | const Double_t kRTPC1 =calROC->GetPadRowRadii(36,calROC->GetNRows(36)-1); | |
114 | Float_t rmiddle=(kRTPC0+kRTPC1)/2.; | |
115 | // | |
116 | Double_t phi = TMath::ATan2(x[1],x[0]); | |
117 | Double_t r = TMath::Sqrt(x[1]*x[1]+x[0]*x[0]); | |
118 | Double_t driftN = 1.-TMath::Abs(x[2])/calROC->GetZLength(0); // drift from 0 to 1 | |
119 | Double_t localxN = 2*(r-rmiddle)/(kRTPC1-kRTPC0); // normalize local x position | |
120 | // | |
602803b6 | 121 | Double_t erez = 0; |
122 | Double_t erphiez = 0; | |
123 | if (roc%36<18) erez= GetSum(*fPolynomA, *fPolynomValA, localxN, driftN, phi,0); | |
124 | if (roc%36>=18) erez= GetSum(*fPolynomC, *fPolynomValC, localxN, driftN, phi,0); | |
125 | if (roc%36<18) erphiez= GetSum(*fPolynomA, *fPolynomValA, localxN, driftN, phi,1); | |
126 | if (roc%36>=18) erphiez= GetSum(*fPolynomC, *fPolynomValC, localxN, driftN, phi,1); | |
127 | ||
128 | Double_t dr = fC0 * erez + fC1 * erphiez; | |
129 | Double_t drphi = -fC1 * erez + fC0 * erphiez; | |
d2faad4f | 130 | |
131 | // Calculate distorted position | |
132 | if ( r > 0.0 ) { | |
133 | r = r + dr; | |
134 | phi = phi + drphi/r; | |
135 | } | |
136 | // Calculate correction in cartesian coordinates | |
137 | dx[0] = r * TMath::Cos(phi) - x[0]; | |
138 | dx[1] = r * TMath::Sin(phi) - x[1]; | |
139 | dx[2] = 0.; // z distortion not implemented (1st order distortions) | |
ae425f91 | 140 | |
141 | } | |
142 | ||
143 | ||
144 | ||
145 | Double_t AliTPCExBEffective::GetSum(const TMatrixD& mpol, const TMatrixD&mcoef, Double_t r, Double_t drift, Double_t phi, Int_t coord) const { | |
146 | // | |
d2faad4f | 147 | // Summation of the polynomials |
ae425f91 | 148 | // |
149 | Int_t npols=mpol.GetNrows(); | |
150 | Double_t sum=0; | |
151 | for (Int_t ipol=0;ipol<npols; ipol++){ | |
152 | Double_t pR = 1, pD=1, pPhi=1; | |
153 | Int_t icoord = TMath::Nint(mpol(ipol,0)); | |
154 | if (icoord!=coord) continue; | |
155 | Int_t npolR = TMath::Nint(mpol(ipol,1)); | |
156 | Int_t npolD = TMath::Nint(mpol(ipol,2)); | |
157 | Int_t npolPhi = TMath::Nint(mpol(ipol,3)); | |
158 | Double_t coef=mcoef(ipol,0); | |
159 | // | |
160 | for (Int_t ipolR=1; ipolR<=npolR; ipolR++) pR*=r; // use simple polynoms | |
161 | for (Int_t ipolD=1; ipolD<=npolD; ipolD++) pD*=drift; // use simple polynoms | |
162 | pPhi=TMath::Cos(npolPhi*phi); | |
163 | sum+= pR*pD*pPhi*coef; | |
164 | } | |
165 | return sum; | |
166 | } | |
167 | ||
168 | ||
169 | void AliTPCExBEffective::SetPolynoms(const TMatrixD *polA,const TMatrixD *polC){ | |
170 | // | |
171 | // Set correction polynom - coefficients | |
172 | // | |
173 | fPolynomA = new TMatrixD(*polA); | |
174 | fPolynomC = new TMatrixD(*polC); | |
175 | } | |
176 | ||
177 | void AliTPCExBEffective::SetCoeficients(const TMatrixD *valA,const TMatrixD *valC){ | |
178 | // | |
179 | // Set correction polynom - coefficients | |
180 | // | |
181 | fPolynomValA = new TMatrixD(*valA); | |
182 | fPolynomValC = new TMatrixD(*valC); | |
183 | } | |
184 | ||
f1fd5b3f | 185 | |
186 | ||
187 | ||
188 | void AliTPCExBEffective::Print(const Option_t* option) const { | |
189 | // | |
190 | // Print function to check the settings (e.g. the twist in the X direction) | |
191 | // option=="a" prints the C0 and C1 coefficents for calibration purposes | |
192 | // | |
193 | ||
194 | TString opt = option; opt.ToLower(); | |
195 | printf("%s\t%s\n",GetName(),GetTitle()); | |
196 | ||
197 | if (opt.Contains("a")) { // Print all details | |
198 | printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2); | |
199 | printf(" - C0: %1.4f, C1: %1.4f \n",fC0,fC1); | |
200 | fPolynomValA->Print(); | |
201 | fPolynomValC->Print(); | |
202 | } | |
203 | ||
204 | ||
205 | } |