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237c933d | 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 | ||
16 | /* | |
17 | $Log$ | |
a2f7eaf6 | 18 | Revision 1.2 2000/10/02 21:28:12 fca |
19 | Removal of useless dependecies via forward declarations | |
20 | ||
94de3818 | 21 | Revision 1.1 2000/06/12 15:29:37 jbarbosa |
22 | Cleaned up version. | |
23 | ||
237c933d | 24 | */ |
25 | ||
26 | #include "AliRICHResponseV0.h" | |
a2f7eaf6 | 27 | #include "AliSegmentation.h" |
237c933d | 28 | #include "AliRun.h" |
94de3818 | 29 | #include "AliMC.h" |
237c933d | 30 | |
31 | #include <TMath.h> | |
32 | #include <TRandom.h> | |
33 | #include <TParticle.h> | |
34 | //___________________________________________ | |
35 | ClassImp(AliRICHResponseV0) | |
36 | ||
37 | Float_t AliRICHResponseV0::IntPH(Float_t eloss) | |
38 | { | |
39 | // Get number of electrons and return charge | |
40 | ||
41 | Int_t nel; | |
42 | nel= Int_t(eloss/fEIonisation); | |
43 | ||
44 | Float_t charge=0; | |
45 | if (nel == 0) nel=1; | |
46 | for (Int_t i=1;i<=nel;i++) { | |
47 | charge -= fChargeSlope*TMath::Log(gRandom->Rndm()); | |
48 | } | |
49 | return charge; | |
50 | } | |
51 | ||
52 | Float_t AliRICHResponseV0::IntPH() | |
53 | { | |
54 | ||
55 | // Get number of electrons and return charge, for a single photon | |
56 | ||
57 | Float_t charge = -fChargeSlope*TMath::Log(gRandom->Rndm()); | |
58 | return charge; | |
59 | } | |
60 | ||
61 | ||
62 | ||
63 | // ------------------------------------------- | |
a2f7eaf6 | 64 | Float_t AliRICHResponseV0::IntXY(AliSegmentation * segmentation) |
237c933d | 65 | { |
66 | ||
67 | const Float_t kInversePitch = 1/fPitch; | |
68 | Float_t response; | |
69 | // | |
70 | // Integration limits defined by segmentation model | |
71 | // | |
72 | ||
73 | Float_t xi1, xi2, yi1, yi2; | |
74 | segmentation->IntegrationLimits(xi1,xi2,yi1,yi2); | |
75 | ||
76 | xi1=xi1*kInversePitch; | |
77 | xi2=xi2*kInversePitch; | |
78 | yi1=yi1*kInversePitch; | |
79 | yi2=yi2*kInversePitch; | |
80 | ||
81 | //printf("Integration Limits: %f-%f, %f-%f\n",xi1,xi2,yi1,yi2); | |
82 | ||
83 | //printf("KInversePitch:%f\n",kInversePitch); | |
84 | ||
85 | // | |
86 | // The Mathieson function | |
87 | Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1); | |
88 | Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2); | |
89 | ||
90 | Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1); | |
91 | Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2); | |
92 | ||
93 | //printf("Integration Data: %f-%f, %f-%f\n",ux1,ux2,uy1,uy2); | |
94 | ||
95 | //printf("%f %f %f %f\n",fSqrtKx3,fKx2,fKy4,fKx4); | |
96 | ||
97 | response=4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1)); | |
98 | ||
99 | //printf("Response:%f\n",response); | |
100 | ||
101 | return response; | |
102 | ||
103 | } | |
104 | ||
105 | Int_t AliRICHResponseV0::FeedBackPhotons(Float_t *source, Float_t qtot) | |
106 | { | |
107 | // | |
108 | // Generate FeedBack photons | |
109 | // | |
110 | Int_t j, ipart, nt; | |
111 | ||
112 | Int_t sNfeed=0; | |
113 | ||
114 | ||
115 | // Local variables | |
116 | Float_t cthf, ranf[2], phif, enfp = 0, sthf; | |
117 | Int_t i, ifeed; | |
118 | Float_t e1[3], e2[3], e3[3]; | |
119 | Float_t vmod, uswop; | |
120 | Float_t fp, random; | |
121 | Float_t dir[3], phi; | |
122 | Int_t nfp; | |
123 | Float_t pol[3], mom[3]; | |
124 | TLorentzVector position; | |
125 | // | |
126 | // Determine number of feedback photons | |
127 | ||
128 | // Get weight of current particle | |
129 | TParticle *current = (TParticle*) | |
130 | (*gAlice->Particles())[gAlice->CurrentTrack()]; | |
131 | ||
132 | ifeed = Int_t(current->GetWeight()/100+0.5); | |
133 | ipart = gMC->TrackPid(); | |
134 | fp = fAlphaFeedback * qtot; | |
135 | nfp = gRandom->Poisson(fp); | |
136 | ||
137 | // This call to fill the time of flight | |
138 | gMC->TrackPosition(position); | |
139 | // | |
140 | // Generate photons | |
141 | for (i = 0; i <nfp; i++) { | |
142 | ||
143 | // Direction | |
144 | gMC->Rndm(ranf, 2); | |
145 | cthf = ranf[0] * 2 - 1.; | |
146 | if (cthf < 0) continue; | |
147 | sthf = TMath::Sqrt((1 - cthf) * (1 + cthf)); | |
148 | phif = ranf[1] * 2 * TMath::Pi(); | |
149 | // | |
150 | gMC->Rndm(&random, 1); | |
151 | if (random <= .57) { | |
152 | enfp = 7.5e-9; | |
153 | } else if (random <= .7) { | |
154 | enfp = 6.4e-9; | |
155 | } else { | |
156 | enfp = 7.9e-9; | |
157 | } | |
158 | ||
159 | dir[0] = sthf * TMath::Sin(phif); | |
160 | dir[1] = cthf; | |
161 | dir[2] = sthf * TMath::Cos(phif); | |
162 | gMC->Gdtom(dir, mom, 2); | |
163 | mom[0]*=enfp; | |
164 | mom[1]*=enfp; | |
165 | mom[2]*=enfp; | |
166 | ||
167 | // Polarisation | |
168 | e1[0] = 0; | |
169 | e1[1] = -dir[2]; | |
170 | e1[2] = dir[1]; | |
171 | ||
172 | e2[0] = -dir[1]; | |
173 | e2[1] = dir[0]; | |
174 | e2[2] = 0; | |
175 | ||
176 | e3[0] = dir[1]; | |
177 | e3[1] = 0; | |
178 | e3[2] = -dir[0]; | |
179 | ||
180 | vmod=0; | |
181 | for(j=0;j<3;j++) vmod+=e1[j]*e1[j]; | |
182 | if (!vmod) for(j=0;j<3;j++) { | |
183 | uswop=e1[j]; | |
184 | e1[j]=e3[j]; | |
185 | e3[j]=uswop; | |
186 | } | |
187 | vmod=0; | |
188 | for(j=0;j<3;j++) vmod+=e2[j]*e2[j]; | |
189 | if (!vmod) for(j=0;j<3;j++) { | |
190 | uswop=e2[j]; | |
191 | e2[j]=e3[j]; | |
192 | e3[j]=uswop; | |
193 | } | |
194 | ||
195 | vmod=0; | |
196 | for(j=0;j<3;j++) vmod+=e1[j]*e1[j]; | |
197 | vmod=TMath::Sqrt(1/vmod); | |
198 | for(j=0;j<3;j++) e1[j]*=vmod; | |
199 | ||
200 | vmod=0; | |
201 | for(j=0;j<3;j++) vmod+=e2[j]*e2[j]; | |
202 | vmod=TMath::Sqrt(1/vmod); | |
203 | for(j=0;j<3;j++) e2[j]*=vmod; | |
204 | ||
205 | gMC->Rndm(ranf, 1); | |
206 | phi = ranf[0] * 2 * TMath::Pi(); | |
207 | for(j=0;j<3;j++) pol[j]=e1[j]*TMath::Sin(phi)+e2[j]*TMath::Cos(phi); | |
208 | gMC->Gdtom(pol, pol, 2); | |
209 | ||
210 | // Put photon on the stack and label it as feedback (51, 52) | |
211 | ++sNfeed; | |
212 | ||
213 | gAlice->SetTrack(Int_t(1), gAlice->CurrentTrack(), Int_t(50000051), | |
214 | mom,source,pol,position[3], | |
215 | "Feedback", nt, 1.); | |
216 | } | |
217 | return(sNfeed); | |
218 | } | |
219 | ||
220 | ||
221 | ||
222 |