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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 | |
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16 | /* $Id$ */ |
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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 | |
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31 | Float_t * AliDetectorParam::GetAnglesAccMomentum(Float_t *x, Int_t * /*index*/, Float_t *momentum, Float_t *angle) |
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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) |
git://git.uio.no / u / mrichter / AliRoot.git / blame