1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
21 #include "AliMUONMathieson.h"
22 #include "AliSegmentation.h"
23 #include "AliMUONGeometrySegmentation.h"
26 ClassImp(AliMUONMathieson)
28 //__________________________________________________________________________
29 AliMUONMathieson::AliMUONMathieson() :
38 // Default constructor
42 //__________________________________________________________________________
43 void AliMUONMathieson::SetSqrtKx3AndDeriveKx2Kx4(Float_t SqrtKx3)
45 // Set to "SqrtKx3" the Mathieson parameter K3 ("fSqrtKx3")
46 // in the X direction, perpendicular to the wires,
47 // and derive the Mathieson parameters K2 ("fKx2") and K4 ("fKx4")
48 // in the same direction
50 fKx2 = TMath::Pi() / 2. * (1. - 0.5 * fSqrtKx3);
51 Float_t cx1 = fKx2 * fSqrtKx3 / 4. / TMath::ATan(Double_t(fSqrtKx3));
52 fKx4 = cx1 / fKx2 / fSqrtKx3;
55 //__________________________________________________________________________
56 void AliMUONMathieson::SetSqrtKy3AndDeriveKy2Ky4(Float_t SqrtKy3)
58 // Set to "SqrtKy3" the Mathieson parameter K3 ("fSqrtKy3")
59 // in the Y direction, along the wires,
60 // and derive the Mathieson parameters K2 ("fKy2") and K4 ("fKy4")
61 // in the same direction
63 fKy2 = TMath::Pi() / 2. * (1. - 0.5 * fSqrtKy3);
64 Float_t cy1 = fKy2 * fSqrtKy3 / 4. / TMath::ATan(Double_t(fSqrtKy3));
65 fKy4 = cy1 / fKy2 / fSqrtKy3;
67 // -------------------------------------------
68 Float_t AliMUONMathieson::IntXY(AliSegmentation * segmentation)
70 // Calculate charge on current pad according to Mathieson distribution
72 const Float_t kInversePitch = 1/fPitch;
74 // Integration limits defined by segmentation model
76 Float_t xi1, xi2, yi1, yi2;
77 segmentation->IntegrationLimits(xi1,xi2,yi1,yi2);
78 xi1=xi1*kInversePitch;
79 xi2=xi2*kInversePitch;
80 yi1=yi1*kInversePitch;
81 yi2=yi2*kInversePitch;
83 // The Mathieson function
84 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
85 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
87 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
88 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
91 return Float_t(4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*
92 fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1)));
94 // -------------------------------------------
95 Float_t AliMUONMathieson::IntXY(Int_t idDE, AliMUONGeometrySegmentation* segmentation)
97 // Calculate charge on current pad according to Mathieson distribution
98 // using Detection elt
100 const Float_t kInversePitch = 1./fPitch;
102 // Integration limits defined by segmentation model
104 Float_t xi1, xi2, yi1, yi2;
105 segmentation->IntegrationLimits(idDE, xi1,xi2,yi1,yi2);
106 xi1=xi1*kInversePitch;
107 xi2=xi2*kInversePitch;
108 yi1=yi1*kInversePitch;
109 yi2=yi2*kInversePitch;
111 // The Mathieson function
112 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
113 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
115 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
116 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
119 return Float_t(4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*
120 fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1)));