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[u/mrichter/AliRoot.git] / TPC / AliDetectorParam.cxx
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cc80f89e 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
88cb7938 16/* $Id$ */
cc80f89e 17
18///////////////////////////////////////////////////////////////////////
19// Paramter class for AliDetector //
20// //
21// Origin: Marian Ivanov, Uni. of Bratislava, ivanov@fmph.uniba.sk //
22// //
23///////////////////////////////////////////////////////////////////////
24
25#include "TObject.h"
26#include "AliDetectorParam.h"
27
28
179c6296 29AliDetectorParam::AliDetectorParam()
30 :TNamed(),
31 fBField(0.),
32 fNPrimLoss(0.),
33 fNTotalLoss(0.)
34{
35 //
36 // default constructor
37 //
38}
cc80f89e 39
176aff27 40Float_t * AliDetectorParam::GetAnglesAccMomentum(Float_t *x, Int_t * /*index*/, Float_t *momentum, Float_t *angle)
cc80f89e 41{
42 //
43 //calculates deflection angle of particle with longitudinal
44 //longitudinal momentum[0] and transversal momentum momentum[1]
45 //at position (x,y,z) = (x[0],x[1],x[2])
46 //angle[0] - deep angle
47 //angle[1] - magnetic deflection angle
48 if (momentum==0) {
49 Float_t rtotal =TMath::Sqrt(x[0]*x[0]+x[1]*x[1]);
50 if (rtotal==0) angle[0]=0;
51 else
52 angle[0] = TMath::ATan(x[2]/rtotal);
53 angle[1]=0;
54 return angle;
55 }
56 Float_t mtotal =TMath::Sqrt(momentum[0]*momentum[0]+momentum[1]*momentum[1]);
57 if (mtotal==0) {
58 angle[0]= 0;
59 angle[1]=0;
60 return angle;
61 }
62 angle[0]= TMath::ATan(momentum[2]/mtotal);
63 Float_t radius1 = TMath::Sqrt(x[0]*x[0]+x[1]*x[1]); //axial symetry in z
64 Float_t radius2 = 1000*mtotal/(3*fBField);
65 if (radius1<radius2)
66 angle[1]= TMath::ASin(radius1/radius2);
67 else
68 angle[1]=0;
69 return angle;
70}
71
72
73
74
75
76ClassImp(AliDetectorParam)