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0116859c | 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 | // AliExBBShape class // | |
19 | // The class calculates the space point distortions due to the B field // | |
20 | // shape imperfections using a second order technique based on integrals // | |
21 | // over Bz (e.g. int By/Bz) obtained via the AliMagF class // | |
22 | // The class allows "effective Omega Tau" corrections. // | |
23 | // // | |
24 | // date: 27/04/2010 // | |
25 | // Authors: Magnus Mager, Jim Thomas, Stefan Rossegger // | |
26 | // // | |
27 | // Example usage: // | |
28 | // AliMagF mag("mag","mag"); // | |
29 | // AliTPCExBBShape exb; // | |
30 | // exb.SetBField(&mag); // use Bfield from AliMagF // | |
31 | // exb.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB // | |
32 | // // plot dRPhi distortions ... // | |
33 | // exb.CreateHistoDRPhiinZR(0,100,100)->Draw("surf2"); // | |
34 | //////////////////////////////////////////////////////////////////////////// | |
35 | ||
36 | #include <AliMagF.h> | |
534fd34a | 37 | #include "TGeoGlobalMagField.h" |
38 | #include "AliTPCcalibDB.h" | |
39 | #include "AliTPCParam.h" | |
40 | #include "AliLog.h" | |
0116859c | 41 | |
42 | #include "AliTPCExBBShape.h" | |
43 | ||
44 | AliTPCExBBShape::AliTPCExBBShape() | |
45 | : AliTPCCorrection("exb_bshape","ExB B-shape"), | |
46 | fC1(0.),fC2(0.), | |
47 | fBField(0) | |
48 | { | |
49 | // | |
50 | // default constructor | |
51 | // | |
52 | } | |
53 | ||
54 | AliTPCExBBShape::~AliTPCExBBShape() { | |
55 | // | |
56 | // virtual destructor | |
57 | // | |
58 | } | |
59 | ||
e527a1b9 | 60 | void AliTPCExBBShape::Init() { |
61 | // | |
534fd34a | 62 | // Initialization funtion |
e527a1b9 | 63 | // |
64 | ||
534fd34a | 65 | AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField(); |
66 | if (!magF) AliError("Magneticd field - not initialized"); | |
67 | Double_t bzField = magF->SolenoidField()/10.; //field in T | |
68 | SetBField(magF); | |
69 | AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters(); | |
70 | if (!param) AliError("Parameters - not initialized"); | |
71 | Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally) | |
e527a1b9 | 72 | Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully) |
73 | Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; | |
e527a1b9 | 74 | // Correction Terms for effective omegaTau; obtained by a laser calibration run |
534fd34a | 75 | SetOmegaTauT1T2(wt,fT1,fT2); |
e527a1b9 | 76 | |
77 | ||
78 | } | |
79 | ||
80 | void AliTPCExBBShape::Update(const TTimeStamp &/*timeStamp*/) { | |
81 | // | |
82 | // Update function | |
83 | // | |
534fd34a | 84 | AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField(); |
85 | if (!magF) AliError("Magneticd field - not initialized"); | |
86 | Double_t bzField = magF->SolenoidField()/10.; //field in T | |
87 | SetBField(magF); | |
88 | AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters(); | |
89 | if (!param) AliError("Parameters - not initialized"); | |
90 | Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally) | |
e527a1b9 | 91 | Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully) |
92 | Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; | |
e527a1b9 | 93 | // Correction Terms for effective omegaTau; obtained by a laser calibration run |
534fd34a | 94 | SetOmegaTauT1T2(wt,fT1,fT2); |
e527a1b9 | 95 | |
96 | ||
97 | } | |
98 | ||
99 | ||
100 | ||
0116859c | 101 | void AliTPCExBBShape::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) { |
102 | // | |
103 | // Calculates the space point corrections of the B field inperfections (B field shape) | |
104 | // | |
105 | ||
106 | if (!fBField) { | |
107 | for (Int_t j=0;j<3;++j) dx[j]=0.; | |
108 | return; | |
109 | } | |
110 | ||
111 | const Double_t xStart[3]={ x[0], x[1], x[2] }; | |
b1f0a2a5 | 112 | const Double_t xEnd[3]={ x[0], x[1], roc%36<18?fgkTPCZ0:-fgkTPCZ0 }; |
0116859c | 113 | |
114 | Double_t intBStart[3]; | |
115 | Double_t intBEnd[3]; | |
116 | ||
117 | fBField->GetTPCRatInt(xStart,intBStart); | |
118 | fBField->GetTPCRatInt(xEnd, intBEnd ); | |
119 | ||
120 | const Float_t intBxOverBz=(intBEnd[0]-intBStart[0]); | |
121 | const Float_t intByOverBz=(intBEnd[1]-intBStart[1]); | |
122 | ||
123 | dx[0]=fC2*intBxOverBz-fC1*intByOverBz; | |
124 | dx[1]=fC1*intBxOverBz+fC2*intByOverBz; | |
125 | dx[2]=0.; | |
126 | ||
127 | ||
128 | } | |
129 | ||
130 | void AliTPCExBBShape::GetBxAndByOverBz(const Float_t x[],const Short_t roc,Float_t BxByOverBz[]) { | |
131 | // | |
132 | // This function is purely for calibration purposes | |
133 | // Returns the via AliMagF obtaind B field integrals | |
134 | // | |
135 | ||
136 | if (!fBField) { | |
137 | for (Int_t j=0;j<3;++j) BxByOverBz[j]=0.; | |
138 | return; | |
139 | } | |
140 | ||
141 | const Double_t xStart[3]={ x[0], x[1], x[2] }; | |
b1f0a2a5 | 142 | const Double_t xEnd[3]={ x[0], x[1], roc%36<18?fgkTPCZ0:-fgkTPCZ0 }; |
0116859c | 143 | |
144 | Double_t intBStart[3]; | |
145 | Double_t intBEnd[3]; | |
146 | ||
147 | fBField->GetTPCRatInt(xStart,intBStart); | |
148 | fBField->GetTPCRatInt(xEnd, intBEnd ); | |
149 | ||
150 | const Float_t intBxOverBz=(intBEnd[0]-intBStart[0]); | |
151 | const Float_t intByOverBz=(intBEnd[1]-intBStart[1]); | |
152 | ||
153 | BxByOverBz[0]=intBxOverBz; | |
154 | BxByOverBz[1]=intByOverBz; | |
155 | ||
156 | } | |
157 | ||
158 | void AliTPCExBBShape::Print(Option_t* option) const { | |
159 | // | |
160 | // Print function to check the settings (e.g. voltage offsets) | |
161 | // option=="a" prints details of the B field settings and the | |
162 | // C0 and C1 coefficents (for calibration purposes) | |
163 | // | |
164 | TString opt = option; opt.ToLower(); | |
534fd34a | 165 | printf("%s\t%s\n - B field settings:\n",GetTitle(),GetName()); |
0116859c | 166 | fBField->Print(option); |
167 | // printf(" - B field: X-Twist: %1.5lf rad, Y-Twist: %1.5lf rad \n",fBField->Print(option)); | |
534fd34a | 168 | if (opt.Contains("a")) { // Print all details |
169 | printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2); | |
0116859c | 170 | printf(" - C1: %1.4f, C2: %1.4f \n",fC1,fC2); |
171 | } | |
0116859c | 172 | } |