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Minor changes to the Digitizer procedure
[u/mrichter/AliRoot.git] / RICH / AliRICHResponseV0.cxx
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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 $Log$
3c5ffeb4 18 Revision 1.6 2001/02/23 17:39:02 jbarbosa
19 Removed verbose output.
20
d65c4a20 21 Revision 1.5 2001/02/23 17:25:08 jbarbosa
22 Re-definition of IntPH() to accomodate for wire sag effect.
23
733b4fa4 24 Revision 1.4 2000/12/01 17:37:44 morsch
25 Replace in argument of SetTrack(..) string constant by kPFeedBackPhoton.
26
9e4670f0 27 Revision 1.3 2000/10/03 21:44:09 morsch
28 Use AliSegmentation and AliHit abstract base classes.
29
a2f7eaf6 30 Revision 1.2 2000/10/02 21:28:12 fca
31 Removal of useless dependecies via forward declarations
32
94de3818 33 Revision 1.1 2000/06/12 15:29:37 jbarbosa
34 Cleaned up version.
35
237c933d 36*/
37
38#include "AliRICHResponseV0.h"
a2f7eaf6 39#include "AliSegmentation.h"
237c933d 40#include "AliRun.h"
94de3818 41#include "AliMC.h"
237c933d 42
43#include <TMath.h>
44#include <TRandom.h>
45#include <TParticle.h>
46//___________________________________________
47ClassImp(AliRICHResponseV0)
48
733b4fa4 49Float_t AliRICHResponseV0::IntPH(Float_t eloss, Float_t yhit)
237c933d 50{
51 // Get number of electrons and return charge
52
53 Int_t nel;
54 nel= Int_t(eloss/fEIonisation);
55
56 Float_t charge=0;
733b4fa4 57 Double_t gain_var=1;
58
237c933d 59 if (nel == 0) nel=1;
733b4fa4 60
61 if (fWireSag)
62 {
63 //printf("Voltage:%d, Yhit:%f\n",fVoltage, yhit);
64
65 if (fVoltage==2150)
66 {
67 gain_var = 9e-6*TMath::Power(yhit,4) + 2e-7*TMath::Power(yhit,3) - 0.0316*TMath::Power(yhit,2) - 3e-4*yhit + 25.367;
68 //gain_var = 9e-5*TMath::Power(yhit,4) + 2e-6*TMath::Power(yhit,3) - 0.316*TMath::Power(yhit,2) - 3e-3*yhit + 253.67;
69 }
70 if (fVoltage==2100)
71 gain_var = 8e-6*TMath::Power(yhit,4) + 2e-7*TMath::Power(yhit,3) - 0.0283*TMath::Power(yhit,2) - 2e-4*yhit + 23.015;
72 if (fVoltage==2050)
73 gain_var = 7e-6*TMath::Power(yhit,4) + 1e-7*TMath::Power(yhit,3) - 0.0254*TMath::Power(yhit,2) - 2e-4*yhit + 20.888;
74 if (fVoltage==2000)
75 gain_var = 6e-6*TMath::Power(yhit,4) + 8e-8*TMath::Power(yhit,3) - 0.0227*TMath::Power(yhit,2) - 1e-4*yhit + 18.961;
76
77 gain_var = gain_var/100;
78 //printf("Yhit:%f, Gain variation:%f\n",yhit,gain_var);
79
80 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
d65c4a20 81 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
733b4fa4 82
83 for (Int_t i=1;i<=nel;i++) {
84 charge -= gain*TMath::Log(gRandom->Rndm());
85 }
86 }
87 else
88 {
89 for (Int_t i=1;i<=nel;i++) {
90 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
91 }
92 }
93
237c933d 94 return charge;
95}
96
733b4fa4 97Float_t AliRICHResponseV0::IntPH(Float_t yhit)
237c933d 98{
99
100// Get number of electrons and return charge, for a single photon
101
733b4fa4 102 Float_t charge=0;
103 Double_t gain_var=1;
104
105 if (fWireSag)
106 {
107 if (fVoltage==2150)
108 {
109 gain_var = 9e-6*TMath::Power(yhit,4) + 2e-7*TMath::Power(yhit,3) - 0.0316*TMath::Power(yhit,2) - 3e-4*yhit + 25.367;
110 //gain_var = 9e-5*TMath::Power(yhit,4) + 2e-6*TMath::Power(yhit,3) - 0.316*TMath::Power(yhit,2) - 3e-3*yhit + 253.67;
111 }
112 if (fVoltage==2100)
113 gain_var = 8e-6*TMath::Power(yhit,4) + 2e-7*TMath::Power(yhit,3) - 0.0283*TMath::Power(yhit,2) - 2e-4*yhit + 23.015;
114 if (fVoltage==2050)
115 gain_var = 7e-6*TMath::Power(yhit,4) + 1e-7*TMath::Power(yhit,3) - 0.0254*TMath::Power(yhit,2) - 2e-4*yhit + 20.888;
116 if (fVoltage==2000)
117 gain_var = 6e-6*TMath::Power(yhit,4) + 8e-8*TMath::Power(yhit,3) - 0.0227*TMath::Power(yhit,2) - 1e-4*yhit + 18.961;
118
119 gain_var = gain_var/100;
120 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain_var);
121
122 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
123
124 charge -= gain*TMath::Log(gRandom->Rndm());
d65c4a20 125 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
733b4fa4 126 }
127 else
128 {
129 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
130 }
237c933d 131 return charge;
132}
133
134
135
136// -------------------------------------------
a2f7eaf6 137Float_t AliRICHResponseV0::IntXY(AliSegmentation * segmentation)
237c933d 138{
139
140 const Float_t kInversePitch = 1/fPitch;
141 Float_t response;
142//
143// Integration limits defined by segmentation model
144//
145
146 Float_t xi1, xi2, yi1, yi2;
147 segmentation->IntegrationLimits(xi1,xi2,yi1,yi2);
148
149 xi1=xi1*kInversePitch;
150 xi2=xi2*kInversePitch;
151 yi1=yi1*kInversePitch;
152 yi2=yi2*kInversePitch;
153
154 //printf("Integration Limits: %f-%f, %f-%f\n",xi1,xi2,yi1,yi2);
155
156 //printf("KInversePitch:%f\n",kInversePitch);
157
158 //
159// The Mathieson function
160 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
161 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
162
163 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
164 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
165
166 //printf("Integration Data: %f-%f, %f-%f\n",ux1,ux2,uy1,uy2);
167
168 //printf("%f %f %f %f\n",fSqrtKx3,fKx2,fKy4,fKx4);
169
170 response=4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1));
171
172 //printf("Response:%f\n",response);
173
174 return response;
175
176}
177
178Int_t AliRICHResponseV0::FeedBackPhotons(Float_t *source, Float_t qtot)
179{
180 //
181 // Generate FeedBack photons
182 //
183 Int_t j, ipart, nt;
184
185 Int_t sNfeed=0;
186
187
188 // Local variables
189 Float_t cthf, ranf[2], phif, enfp = 0, sthf;
190 Int_t i, ifeed;
191 Float_t e1[3], e2[3], e3[3];
192 Float_t vmod, uswop;
193 Float_t fp, random;
194 Float_t dir[3], phi;
195 Int_t nfp;
196 Float_t pol[3], mom[3];
197 TLorentzVector position;
198 //
199 // Determine number of feedback photons
200
201 // Get weight of current particle
202 TParticle *current = (TParticle*)
203 (*gAlice->Particles())[gAlice->CurrentTrack()];
204
205 ifeed = Int_t(current->GetWeight()/100+0.5);
206 ipart = gMC->TrackPid();
207 fp = fAlphaFeedback * qtot;
208 nfp = gRandom->Poisson(fp);
209
210 // This call to fill the time of flight
211 gMC->TrackPosition(position);
3c5ffeb4 212 //printf("Track position: %f %f %f %15.12f\n", position[0],position[1],position[2],position[3]);
237c933d 213 //
214 // Generate photons
215 for (i = 0; i <nfp; i++) {
216
217 // Direction
218 gMC->Rndm(ranf, 2);
219 cthf = ranf[0] * 2 - 1.;
220 if (cthf < 0) continue;
221 sthf = TMath::Sqrt((1 - cthf) * (1 + cthf));
222 phif = ranf[1] * 2 * TMath::Pi();
223 //
224 gMC->Rndm(&random, 1);
225 if (random <= .57) {
226 enfp = 7.5e-9;
227 } else if (random <= .7) {
228 enfp = 6.4e-9;
229 } else {
230 enfp = 7.9e-9;
231 }
232
233 dir[0] = sthf * TMath::Sin(phif);
234 dir[1] = cthf;
235 dir[2] = sthf * TMath::Cos(phif);
236 gMC->Gdtom(dir, mom, 2);
237 mom[0]*=enfp;
238 mom[1]*=enfp;
239 mom[2]*=enfp;
3c5ffeb4 240 //printf("Dir %f %f %f\n",dir[0],dir[1],dir[2]);
241 //printf("Momentum %15.12f %15.12f %15.12f\n",mom[0],mom[1],mom[2]);
237c933d 242
243 // Polarisation
244 e1[0] = 0;
245 e1[1] = -dir[2];
246 e1[2] = dir[1];
247
248 e2[0] = -dir[1];
249 e2[1] = dir[0];
250 e2[2] = 0;
251
252 e3[0] = dir[1];
253 e3[1] = 0;
254 e3[2] = -dir[0];
255
256 vmod=0;
257 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
258 if (!vmod) for(j=0;j<3;j++) {
259 uswop=e1[j];
260 e1[j]=e3[j];
261 e3[j]=uswop;
262 }
263 vmod=0;
264 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
265 if (!vmod) for(j=0;j<3;j++) {
266 uswop=e2[j];
267 e2[j]=e3[j];
268 e3[j]=uswop;
269 }
270
271 vmod=0;
272 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
273 vmod=TMath::Sqrt(1/vmod);
274 for(j=0;j<3;j++) e1[j]*=vmod;
275
276 vmod=0;
277 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
278 vmod=TMath::Sqrt(1/vmod);
279 for(j=0;j<3;j++) e2[j]*=vmod;
280
281 gMC->Rndm(ranf, 1);
282 phi = ranf[0] * 2 * TMath::Pi();
283 for(j=0;j<3;j++) pol[j]=e1[j]*TMath::Sin(phi)+e2[j]*TMath::Cos(phi);
284 gMC->Gdtom(pol, pol, 2);
285
286 // Put photon on the stack and label it as feedback (51, 52)
287 ++sNfeed;
288
289 gAlice->SetTrack(Int_t(1), gAlice->CurrentTrack(), Int_t(50000051),
3c5ffeb4 290 mom[0],mom[1],mom[2],mom[3],source[0],source[1],source[2],position[3],pol[0],pol[1],pol[2],
9e4670f0 291 kPFeedBackPhoton, nt, 1.);
3c5ffeb4 292
293 //printf("Adding feedback with tof %f and going to %f %f %f\n",position[3],mom[0],mom[1],mom[2]);
237c933d 294 }
3c5ffeb4 295 //if(sNfeed)
296 //printf("feedbacks produced:%d\n",sNfeed);
237c933d 297 return(sNfeed);
298}
299
300
301
302