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 #include <TParticle.h>
20 #include <TVirtualMC.h>
22 #include "AliRICHResponse.h"
24 #include "AliSegmentation.h"
27 ClassImp(AliRICHResponse)
28 //__________________________________________________________________________________________________
29 AliRICHResponse::AliRICHResponse()
31 SetSigmaIntegration(5.);
33 SetChargeSpread(0.18, 0.18);
35 SetAlphaFeedback(0.036);
36 SetEIonisation(26.e-9);
37 SetSqrtKx3(0.77459667);
40 SetSqrtKy3(0.77459667);
44 SetWireSag(1); // 1->On, 0->Off
45 SetVoltage(2150); // Should only be 2000, 2050, 2100 or 2150
46 }//AliRICHResponse::ctor()
47 //__________________________________________________________________________________________________
48 Float_t AliRICHResponse::IntPH(Float_t eloss, Float_t yhit)
50 // Get number of electrons and return charge
53 nel= Int_t(eloss/fEIonisation);
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;
67 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;
69 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;
71 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;
73 gain_var = gain_var/100;
74 //printf("Yhit:%f, Gain variation:%f\n",yhit,gain_var);
76 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
77 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
79 for (Int_t i=1;i<=nel;i++) {
80 charge -= gain*TMath::Log(gRandom->Rndm());
85 for (Int_t i=1;i<=nel;i++) {
86 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
92 //__________________________________________________________________________________________________
93 Float_t AliRICHResponse::IntPH(Float_t yhit)
94 {// Get number of electrons and return charge, for a single photon
103 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;
104 //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;
107 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;
109 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;
111 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;
113 gain_var = gain_var/100;
114 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain_var);
116 Float_t gain = (fChargeSlope + fChargeSlope*gain_var)*.9;
118 charge -= gain*TMath::Log(gRandom->Rndm());
119 //printf(" Yhit:%f, Gain variation:%f\n",yhit, gain);
123 charge -= fChargeSlope*TMath::Log(gRandom->Rndm());
127 //__________________________________________________________________________________________________
128 Float_t AliRICHResponse::IntXY(AliSegmentation * segmentation)
131 const Float_t kInversePitch = 1/fPitch;
134 // Integration limits defined by segmentation model
136 Float_t xi1, xi2, yi1, yi2;
137 segmentation->IntegrationLimits(xi1,xi2,yi1,yi2);
139 xi1=xi1*kInversePitch;
140 xi2=xi2*kInversePitch;
141 yi1=yi1*kInversePitch;
142 yi2=yi2*kInversePitch;
144 //printf("Integration Limits: %f-%f, %f-%f\n",xi1,xi2,yi1,yi2);
146 //printf("KInversePitch:%f\n",kInversePitch);
149 // The Mathieson function
150 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
151 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
153 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
154 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
156 //printf("Integration Data: %f-%f, %f-%f\n",ux1,ux2,uy1,uy2);
158 //printf("%f %f %f %f\n",fSqrtKx3,fKx2,fKy4,fKx4);
160 response=4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1));
162 //printf("Response:%f\n",response);
167 //__________________________________________________________________________________________________
168 Int_t AliRICHResponse::FeedBackPhotons(Float_t *source, Float_t qtot)
169 { // Generate FeedBack photons
177 Float_t cthf, phif, enfp = 0, sthf;
179 Float_t e1[3], e2[3], e3[3];
185 Float_t pol[3], mom[4];
186 TLorentzVector position;
188 // Determine number of feedback photons
190 // Get weight of current particle
191 TParticle *current = (TParticle*)
192 (*gAlice->GetMCApp()->Particles())[gAlice->GetMCApp()->GetCurrentTrackNumber()];
194 ifeed = Int_t(current->GetWeight()/100+0.5);
195 ipart = gMC->TrackPid();
196 fp = fAlphaFeedback * qtot;
197 nfp = gRandom->Poisson(fp);
199 // This call to fill the time of flight
200 gMC->TrackPosition(position);
201 //printf("Track position: %f %f %f %15.12f\n", position[0],position[1],position[2],position[3]);
204 for (i = 0; i <nfp; i++) {
207 gMC->GetRandom()->RndmArray(2,ranf);
208 cthf = ranf[0] * 2 - 1.;
209 if (cthf < 0) continue;
210 sthf = TMath::Sqrt((1 - cthf) * (1 + cthf));
211 phif = ranf[1] * 2 * TMath::Pi();
213 //gMC->Rndm(&random, 1);
214 gMC->GetRandom()->RndmArray(1, &random);
217 } else if (random <= .7) {
223 dir[0] = sthf * TMath::Sin(phif);
225 dir[2] = sthf * TMath::Cos(phif);
226 gMC->Gdtom(dir, mom, 2);
230 mom[3] = TMath::Sqrt(mom[0]*mom[0]+mom[1]*mom[1]+mom[2]*mom[2]);
231 //printf("Dir %f %f %f\n",dir[0],dir[1],dir[2]);
232 //printf("Momentum %15.12f %15.12f %15.12f\n",mom[0],mom[1],mom[2]);
233 //printf("Energy %e\n", mom[3]);
249 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
250 if (!vmod) for(j=0;j<3;j++) {
256 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
257 if (!vmod) for(j=0;j<3;j++) {
264 for(j=0;j<3;j++) vmod+=e1[j]*e1[j];
265 vmod=TMath::Sqrt(1/vmod);
266 for(j=0;j<3;j++) e1[j]*=vmod;
269 for(j=0;j<3;j++) vmod+=e2[j]*e2[j];
270 vmod=TMath::Sqrt(1/vmod);
271 for(j=0;j<3;j++) e2[j]*=vmod;
273 //gMC->Rndm(ranf, 1);
274 gMC->GetRandom()->RndmArray(1,ranf);
275 phi = ranf[0] * 2 * TMath::Pi();
276 for(j=0;j<3;j++) pol[j]=e1[j]*TMath::Sin(phi)+e2[j]*TMath::Cos(phi);
277 gMC->Gdtom(pol, pol, 2);
279 // Put photon on the stack and label it as feedback (51, 52)
282 gAlice->GetMCApp()->PushTrack(Int_t(1), gAlice->GetMCApp()->GetCurrentTrackNumber(), Int_t(50000051),
283 mom[0],mom[1],mom[2],mom[3],source[0],source[1],source[2],position[3],pol[0],pol[1],pol[2],
284 kPFeedBackPhoton, nt, 1.);