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[u/mrichter/AliRoot.git] / TPC / AliTPCGGVoltError.h
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b1f0a2a5 1#ifndef ALI_TPCGG_VOLT_ERROR_H
2#define ALI_TPCGG_VOLT_ERROR_H
0116859c 3
4/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
5 * See cxx source for full Copyright notice */
6
b4caed64 7// _________________________________________________________________
8//
9// Begin_Html
10// <h2> AliTPCGGVoltError class </h2>
11// The class calculates the electric field and the resulting space point distortions
12// due a Gating Grid (GG) voltage error. It uses the analytical solution for such a problem.
13// <p>
14// The input is the effective GG voltage residual in respect to the ideal setting. The effective
15// residual voltage can be set via the functions SetDeltaVGGx. Note that this effective
16// voltage-residuals are approx. a factor 0.9 lower than the actual difference in the setting
17// of the GG due to the fact that the voltage on the GG is partially screened by the wire
18// structure. The calculation has to be performed with the observable effective voltage difference.
19// <p>
20// Unfortunately, the class is not capable of calculation the $dz$ offset due to possible changes
21// of the drift velocity in dependence of the electric field. The special case of the numerical
22// approximation (AliTPCBoundaryVoltError), which is capable of calculating the same effect, should
23// be used for this purpose.
24// End_Html
25//
26// Begin_Macro(source)
27// {
28// gROOT->SetStyle("Plain"); gStyle->SetPalette(1);
29// TCanvas *c2 = new TCanvas("c2","c2",500,300);
30// AliTPCGGVoltError gg;
31// gg.SetDeltaVGGA(-40); gg.SetDeltaVGGC(-40); // 40 Volt offset
32// gg.InitGGVoltErrorDistortion();
33// gg.SetOmegaTauT1T2(0,1,1); // B=0
34// gg.CreateHistoDRinZR(0)->Draw("surf2");
35// return c2;
36// }
37// End_Macro
38//
39// Begin_Html
40// <p>
41// Date: 27/04/2010 <br>
42// Authors: Jim Thomas, Stefan Rossegger, Magnus Mager
43// End_Html
44// _________________________________________________________________
45
0116859c 46
47#include "AliTPCCorrection.h"
48
49class AliTPCGGVoltError : public AliTPCCorrection {
50public:
51 AliTPCGGVoltError();
52 virtual ~AliTPCGGVoltError();
53
e527a1b9 54 // initialization and update functions
55 virtual void Init();
56 virtual void Update(const TTimeStamp &timeStamp);
57
0116859c 58 // common setters and getters for ExB
59 virtual void SetOmegaTauT1T2(Float_t omegaTau,Float_t t1,Float_t t2) {
534fd34a 60 fT1=t1; fT2=t2;
b1f0a2a5 61 const Double_t wt0=t2*omegaTau; fC0=1./(1.+wt0*wt0);
62 const Double_t wt1=t1*omegaTau; fC1=wt1/(1.+wt1*wt1);
0116859c 63 };
64
65 void SetC0C1(Double_t c0,Double_t c1) {fC0=c0;fC1=c1;} // CAUTION: USE WITH CARE
66 Float_t GetC0() const {return fC0;}
67 Float_t GetC1() const {return fC1;}
68
69 // setters and getters for GG
70 void SetDeltaVGGA(Double_t deltaVGGA) {fDeltaVGGA=deltaVGGA;}
71 void SetDeltaVGGC(Double_t deltaVGGC) {fDeltaVGGC=deltaVGGC;}
72 Double_t GetDeltaVGGA() const {return fDeltaVGGA;}
73 Double_t GetDeltaVGGC() const {return fDeltaVGGC;}
74
75 void InitGGVoltErrorDistortion();
76
77 Float_t GetIntErOverEz(const Float_t x[],const Short_t roc);
78
b1f0a2a5 79 virtual void Print(const Option_t* option="") const;
0116859c 80
81protected:
82 virtual void GetCorrection(const Float_t x[],const Short_t roc, Float_t dx[]);
83private:
84
85 Float_t fC0; // coefficient C0 (compare Jim Thomas's notes for definitions)
86 Float_t fC1; // coefficient C1 (compare Jim Thomas's notes for definitions)
87
88 Double_t fDeltaVGGA; // Missmatch of gating grid voltage on A-side [V]
89 Double_t fDeltaVGGC; // Missmatch of gating grid voltage on C-side [V]
90 Double_t fGGVoltErrorER[kNZ][kNR]; // Array to store electric field for GGVoltError calculation
91
1b923461 92 Bool_t fInitLookUp; // flag to check it the Look Up table was created
93
0116859c 94 ClassDef(AliTPCGGVoltError,1);
95};
96
97#endif