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 **************************************************************************/
18 Revision 1.5 2001/02/23 17:25:08 jbarbosa
19 Re-definition of IntPH() to accomodate for wire sag effect.
21 Revision 1.4 2000/12/01 17:37:44 morsch
22 Replace in argument of SetTrack(..) string constant by kPFeedBackPhoton.
24 Revision 1.3 2000/10/03 21:44:09 morsch
25 Use AliSegmentation and AliHit abstract base classes.
27 Revision 1.2 2000/10/02 21:28:12 fca
28 Removal of useless dependecies via forward declarations
30 Revision 1.1 2000/06/12 15:29:37 jbarbosa
35 #include "AliRICHResponseV0.h"
36 #include "AliSegmentation.h"
42 #include <TParticle.h>
43 //___________________________________________
44 ClassImp(AliRICHResponseV0)
46 Float_t AliRICHResponseV0::IntPH(Float_t eloss, Float_t yhit)
48 // Get number of electrons and return charge
51 nel= Int_t(eloss/fEIonisation);
60 //printf("Voltage:%d, Yhit:%f\n",fVoltage, yhit);
64 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;
65 //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;
68 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;
70 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;
72 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;
74 gain_var = gain_var/100;
75 //printf("Yhit:%f, Gain variation:%f\n",yhit,gain_var);
77 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
78 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
80 for (Int_t i=1;i<=nel;i++) {
81 charge -= gain*TMath::Log(gRandom->Rndm());
86 for (Int_t i=1;i<=nel;i++) {
87 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
94 Float_t AliRICHResponseV0::IntPH(Float_t yhit)
97 // Get number of electrons and return charge, for a single photon
106 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;
107 //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;
110 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;
112 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;
114 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;
116 gain_var = gain_var/100;
117 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain_var);
119 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
121 charge -= gain*TMath::Log(gRandom->Rndm());
122 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
126 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
133 // -------------------------------------------
134 Float_t AliRICHResponseV0::IntXY(AliSegmentation * segmentation)
137 const Float_t kInversePitch = 1/fPitch;
140 // Integration limits defined by segmentation model
143 Float_t xi1, xi2, yi1, yi2;
144 segmentation->IntegrationLimits(xi1,xi2,yi1,yi2);
146 xi1=xi1*kInversePitch;
147 xi2=xi2*kInversePitch;
148 yi1=yi1*kInversePitch;
149 yi2=yi2*kInversePitch;
151 //printf("Integration Limits: %f-%f, %f-%f\n",xi1,xi2,yi1,yi2);
153 //printf("KInversePitch:%f\n",kInversePitch);
156 // The Mathieson function
157 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
158 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
160 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
161 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
163 //printf("Integration Data: %f-%f, %f-%f\n",ux1,ux2,uy1,uy2);
165 //printf("%f %f %f %f\n",fSqrtKx3,fKx2,fKy4,fKx4);
167 response=4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1));
169 //printf("Response:%f\n",response);
175 Int_t AliRICHResponseV0::FeedBackPhotons(Float_t *source, Float_t qtot)
178 // Generate FeedBack photons
186 Float_t cthf, ranf[2], phif, enfp = 0, sthf;
188 Float_t e1[3], e2[3], e3[3];
193 Float_t pol[3], mom[3];
194 TLorentzVector position;
196 // Determine number of feedback photons
198 // Get weight of current particle
199 TParticle *current = (TParticle*)
200 (*gAlice->Particles())[gAlice->CurrentTrack()];
202 ifeed = Int_t(current->GetWeight()/100+0.5);
203 ipart = gMC->TrackPid();
204 fp = fAlphaFeedback * qtot;
205 nfp = gRandom->Poisson(fp);
207 // This call to fill the time of flight
208 gMC->TrackPosition(position);
211 for (i = 0; i <nfp; i++) {
215 cthf = ranf[0] * 2 - 1.;
216 if (cthf < 0) continue;
217 sthf = TMath::Sqrt((1 - cthf) * (1 + cthf));
218 phif = ranf[1] * 2 * TMath::Pi();
220 gMC->Rndm(&random, 1);
223 } else if (random <= .7) {
229 dir[0] = sthf * TMath::Sin(phif);
231 dir[2] = sthf * TMath::Cos(phif);
232 gMC->Gdtom(dir, mom, 2);
251 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
252 if (!vmod) for(j=0;j<3;j++) {
258 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
259 if (!vmod) for(j=0;j<3;j++) {
266 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
267 vmod=TMath::Sqrt(1/vmod);
268 for(j=0;j<3;j++) e1[j]*=vmod;
271 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
272 vmod=TMath::Sqrt(1/vmod);
273 for(j=0;j<3;j++) e2[j]*=vmod;
276 phi = ranf[0] * 2 * TMath::Pi();
277 for(j=0;j<3;j++) pol[j]=e1[j]*TMath::Sin(phi)+e2[j]*TMath::Cos(phi);
278 gMC->Gdtom(pol, pol, 2);
280 // Put photon on the stack and label it as feedback (51, 52)
283 gAlice->SetTrack(Int_t(1), gAlice->CurrentTrack(), Int_t(50000051),
284 mom,source,pol,position[3],
285 kPFeedBackPhoton, nt, 1.);