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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 | ||
29 | ||
30 | ||
176aff27 | 31 | Float_t * AliDetectorParam::GetAnglesAccMomentum(Float_t *x, Int_t * /*index*/, Float_t *momentum, Float_t *angle) |
cc80f89e | 32 | { |
33 | // | |
34 | //calculates deflection angle of particle with longitudinal | |
35 | //longitudinal momentum[0] and transversal momentum momentum[1] | |
36 | //at position (x,y,z) = (x[0],x[1],x[2]) | |
37 | //angle[0] - deep angle | |
38 | //angle[1] - magnetic deflection angle | |
39 | if (momentum==0) { | |
40 | Float_t rtotal =TMath::Sqrt(x[0]*x[0]+x[1]*x[1]); | |
41 | if (rtotal==0) angle[0]=0; | |
42 | else | |
43 | angle[0] = TMath::ATan(x[2]/rtotal); | |
44 | angle[1]=0; | |
45 | return angle; | |
46 | } | |
47 | Float_t mtotal =TMath::Sqrt(momentum[0]*momentum[0]+momentum[1]*momentum[1]); | |
48 | if (mtotal==0) { | |
49 | angle[0]= 0; | |
50 | angle[1]=0; | |
51 | return angle; | |
52 | } | |
53 | angle[0]= TMath::ATan(momentum[2]/mtotal); | |
54 | Float_t radius1 = TMath::Sqrt(x[0]*x[0]+x[1]*x[1]); //axial symetry in z | |
55 | Float_t radius2 = 1000*mtotal/(3*fBField); | |
56 | if (radius1<radius2) | |
57 | angle[1]= TMath::ASin(radius1/radius2); | |
58 | else | |
59 | angle[1]=0; | |
60 | return angle; | |
61 | } | |
62 | ||
63 | ||
64 | ||
65 | ||
66 | ||
67 | ClassImp(AliDetectorParam) |