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4c039060 | 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 | $Log$ | |
18 | */ | |
19 | ||
ddae0931 | 20 | #include "AliRICHSegResV0.h" |
21 | #include "AliRun.h" | |
22 | #include "TParticle.h" | |
23 | #include "TMath.h" | |
24 | #include "TRandom.h" | |
25 | ||
26 | ||
27 | ClassImp(AliRICHsegmentation) | |
28 | ClassImp(AliRICHresponse) | |
29 | //___________________________________________ | |
30 | ClassImp(AliRICHsegmentationV0) | |
31 | ||
32 | void AliRICHsegmentationV0::Init(AliRICHchamber* Chamber) | |
33 | { | |
34 | fNpx=(Int_t) (Chamber->ROuter()/fDpx+1); | |
35 | fNpy=(Int_t) (Chamber->ROuter()/fDpy+1); | |
36 | } | |
37 | ||
38 | ||
39 | Float_t AliRICHsegmentationV0::GetAnod(Float_t xhit) | |
40 | { | |
41 | Float_t wire= (xhit>0)? Int_t(xhit/fWireD)+0.5:Int_t(xhit/fWireD)-0.5; | |
42 | return fWireD*wire; | |
43 | } | |
44 | ||
45 | void AliRICHsegmentationV0::SetPADSIZ(Float_t p1, Float_t p2) | |
46 | { | |
47 | fDpx=p1; | |
48 | fDpy=p2; | |
49 | } | |
50 | void AliRICHsegmentationV0::GetPadIxy(Float_t x, Float_t y, Int_t &ix, Int_t &iy) | |
51 | { | |
52 | // returns pad coordinates (ix,iy) for given real coordinates (x,y) | |
53 | // | |
54 | ix = (x>0)? Int_t(x/fDpx)+1 : Int_t(x/fDpx); | |
55 | iy = (y>0)? Int_t(y/fDpy)+1 : Int_t(y/fDpy); | |
56 | if (iy > fNpy) iy= fNpy; | |
57 | if (iy < -fNpy) iy=-fNpy; | |
58 | if (ix > fNpx) ix= fNpx; | |
59 | if (ix < -fNpx) ix=-fNpx; | |
60 | } | |
61 | void AliRICHsegmentationV0:: | |
62 | GetPadCxy(Int_t ix, Int_t iy, Float_t &x, Float_t &y) | |
63 | { | |
64 | // returns real coordinates (x,y) for given pad coordinates (ix,iy) | |
65 | // | |
66 | x = (ix>0) ? Float_t(ix*fDpx)-fDpx/2. : Float_t(ix*fDpx)-fDpx/2.; | |
67 | y = (iy>0) ? Float_t(iy*fDpy)-fDpy/2. : Float_t(iy*fDpy)-fDpy/2.; | |
68 | } | |
69 | ||
70 | void AliRICHsegmentationV0:: | |
71 | FirstPad(Float_t xhit, Float_t yhit, Float_t dx, Float_t dy) | |
72 | { | |
73 | // | |
74 | // Find the wire position (center of charge distribution) | |
75 | Float_t x0a=GetAnod(xhit); | |
76 | // | |
77 | // and take fNsigma*sigma around this center | |
78 | Float_t x01=x0a - dx; | |
79 | Float_t x02=x0a + dx; | |
80 | Float_t y01=yhit - dy; | |
81 | Float_t y02=yhit + dy; | |
82 | // | |
83 | // find the pads over which the charge distributes | |
84 | GetPadIxy(x01,y01,fixmin,fiymin); | |
85 | GetPadIxy(x02,y02,fixmax,fiymax); | |
86 | // | |
87 | // Set current pad to lower left corner | |
88 | fix=fixmin; | |
89 | fiy=fiymin; | |
90 | GetPadCxy(fix,fiy,fx,fy); | |
91 | } | |
92 | ||
93 | void AliRICHsegmentationV0::NextPad() | |
94 | { | |
95 | // | |
96 | // Step to next pad in integration region | |
97 | if (fix != fixmax) { | |
98 | fix++; | |
99 | } else if (fiy != fiymax) { | |
100 | fix=fixmin; | |
101 | fiy++; | |
102 | } else { | |
103 | printf("\n Error: Stepping outside integration region\n "); | |
104 | } | |
105 | GetPadCxy(fix,fiy,fx,fy); | |
106 | } | |
107 | ||
108 | Int_t AliRICHsegmentationV0::MorePads() | |
109 | ||
110 | // | |
111 | // Are there more pads in the integration region | |
112 | { | |
113 | if (fix == fixmax && fiy == fiymax) { | |
114 | return 0; | |
115 | } else { | |
116 | return 1; | |
117 | ||
118 | } | |
119 | } | |
120 | ||
121 | void AliRICHsegmentationV0::SigGenInit(Float_t x,Float_t y,Float_t) | |
122 | { | |
123 | // | |
124 | // Initialises pad and wire position during stepping | |
125 | fxt =x; | |
126 | fyt =y; | |
127 | GetPadIxy(x,y,fixt,fiyt); | |
128 | fiwt=Int_t(x/fWireD)+1; | |
129 | ||
130 | } | |
131 | ||
132 | Int_t AliRICHsegmentationV0::SigGenCond(Float_t x,Float_t y,Float_t) | |
133 | { | |
134 | // | |
135 | // Signal will be generated if particle crosses pad boundary or | |
136 | // boundary between two wires. | |
137 | Int_t ixt, iyt; | |
138 | GetPadIxy(x,y,ixt,iyt); | |
139 | Int_t iwt=Int_t(x/fWireD)+1; | |
140 | ||
141 | if ((ixt != fixt) || (iyt !=fiyt) || (iwt != fiwt)) { | |
142 | return 1; | |
143 | } else { | |
144 | return 0; | |
145 | } | |
146 | } | |
147 | void AliRICHsegmentationV0:: | |
148 | IntegrationLimits(Float_t& x1,Float_t& x2,Float_t& y1, Float_t& y2) | |
149 | { | |
150 | x1=fxt-fx-fDpx/2.; | |
151 | x2=x1+fDpx; | |
152 | y1=fyt-fy-fDpy/2.; | |
153 | y2=y1+fDpy; | |
154 | ||
155 | } | |
156 | ||
157 | void AliRICHsegmentationV0:: | |
158 | Neighbours(Int_t iX, Int_t iY, Int_t* Nlist, Int_t Xlist[7], Int_t Ylist[7]) | |
159 | { | |
160 | //Is used for the cluster finder, include diagonal elements | |
161 | ||
162 | *Nlist=4;Xlist[0]=Xlist[1]=iX;Xlist[2]=iX-1;Xlist[3]=iX+1; | |
163 | Ylist[0]=iY-1;Ylist[1]=iY+1;Ylist[2]=Ylist[3]=iY; | |
164 | } | |
165 | ||
166 | void AliRICHsegmentationV0:: | |
167 | FitXY(AliRICHRecCluster* ,TClonesArray* ) | |
168 | // Default : Centre of gravity method | |
169 | { | |
170 | ; | |
171 | } | |
172 | ||
173 | ||
174 | //___________________________________________ | |
175 | ClassImp(AliRICHresponseV0) | |
176 | Float_t AliRICHresponseV0::IntPH(Float_t eloss) | |
177 | { | |
178 | // Get number of electrons and return charge | |
179 | ||
180 | Int_t nel; | |
181 | //E9/26=magic number should parameter | |
182 | nel= Int_t(eloss*1.e9/26.); | |
183 | Float_t charge=0; | |
184 | if (nel == 0) nel=1; | |
185 | for (Int_t i=1;i<=nel;i++) { | |
186 | charge -= fChslope*TMath::Log(gRandom->Rndm()); | |
187 | } | |
188 | return charge; | |
189 | } | |
190 | // ------------------------------------------- | |
191 | Float_t AliRICHresponseV0::IntXY(AliRICHsegmentation * segmentation) | |
192 | { | |
193 | ||
194 | const Float_t invpitch = 1/fPitch; | |
195 | Float_t response; | |
196 | // | |
197 | // Integration limits defined by segmentation model | |
198 | // | |
199 | ||
200 | Float_t xi1, xi2, yi1, yi2; | |
201 | segmentation->IntegrationLimits(xi1,xi2,yi1,yi2); | |
202 | xi1=xi1*invpitch; | |
203 | xi2=xi2*invpitch; | |
204 | yi1=yi1*invpitch; | |
205 | yi2=yi2*invpitch; | |
206 | ||
207 | // | |
208 | // The Mathieson function | |
209 | Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1); | |
210 | Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2); | |
211 | ||
212 | Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1); | |
213 | Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2); | |
214 | ||
215 | response=4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1)); | |
216 | ||
217 | return response; | |
218 | ||
219 | } | |
220 | //___________________________________________ | |
221 | Int_t AliRICHresponseV0::FeedBackPhotons(Float_t source[3], Float_t qtot) | |
222 | { | |
223 | // | |
224 | // Generate FeedBack photons | |
225 | // | |
226 | Int_t j, ipart, nt; | |
227 | ||
228 | //Probability of feedback | |
229 | Float_t fAlphaFeed=0.05; | |
230 | ||
231 | Int_t sNfeed=0; | |
232 | ||
233 | // Local variables | |
234 | Float_t cthf, ranf[2], phif, enfp = 0, sthf, weight; | |
235 | Int_t i, ifeed; | |
236 | Float_t e1[3], e2[3], e3[3]; | |
237 | Float_t vmod, uswop; | |
238 | Float_t fp, random; | |
239 | Float_t dir[3], phi; | |
240 | Int_t nfp; | |
241 | Float_t pol[3], mom[3]; | |
242 | TLorentzVector position; | |
243 | // | |
244 | // Determine number of feedback photons | |
245 | ||
246 | // Get weight of current particle | |
247 | TParticle *current = (TParticle*) | |
248 | (*gAlice->Particles())[gAlice->CurrentTrack()]; | |
249 | ||
250 | ifeed = Int_t(current->GetWeight()/100+0.5); | |
251 | ipart = gMC->TrackPid(); | |
252 | fp = fAlphaFeed * qtot; | |
253 | nfp = gRandom->Poisson(fp); | |
254 | ||
255 | // This call to fill the time of flight | |
256 | gMC->TrackPosition(position); | |
257 | // | |
258 | // Generate photons | |
259 | for (i = 0; i <nfp; ++i) { | |
260 | ||
261 | // Direction | |
262 | gMC->Rndm(ranf, 2); | |
263 | cthf = ranf[0] * 2 - 1.; | |
264 | if (cthf < 0) continue; | |
265 | sthf = TMath::Sqrt((1 - cthf) * (1 + cthf)); | |
266 | phif = ranf[1] * 2 * TMath::Pi(); | |
267 | // | |
268 | gMC->Rndm(&random, 1); | |
269 | if (random <= .57) { | |
270 | enfp = 7.5e-9; | |
271 | } else if (random <= .7) { | |
272 | enfp = 6.4e-9; | |
273 | } else { | |
274 | enfp = 7.9e-9; | |
275 | } | |
276 | ||
277 | dir[0] = sthf * TMath::Sin(phif); | |
278 | dir[1] = cthf; | |
279 | dir[2] = sthf * TMath::Cos(phif); | |
280 | gMC->Gdtom(dir, mom, 2); | |
281 | mom[0]*=enfp; | |
282 | mom[1]*=enfp; | |
283 | mom[2]*=enfp; | |
284 | ||
285 | // Polarisation | |
286 | e1[0] = 0; | |
287 | e1[1] = -dir[2]; | |
288 | e1[2] = dir[1]; | |
289 | ||
290 | e2[0] = -dir[1]; | |
291 | e2[1] = dir[0]; | |
292 | e2[2] = 0; | |
293 | ||
294 | e3[0] = dir[1]; | |
295 | e3[1] = 0; | |
296 | e3[2] = -dir[0]; | |
297 | ||
298 | vmod=0; | |
299 | for(j=0;j<3;j++) vmod+=e1[j]*e1[j]; | |
300 | if (!vmod) for(j=0;j<3;j++) { | |
301 | uswop=e1[j]; | |
302 | e1[j]=e3[j]; | |
303 | e3[j]=uswop; | |
304 | } | |
305 | vmod=0; | |
306 | for(j=0;j<3;j++) vmod+=e2[j]*e2[j]; | |
307 | if (!vmod) for(j=0;j<3;j++) { | |
308 | uswop=e2[j]; | |
309 | e2[j]=e3[j]; | |
310 | e3[j]=uswop; | |
311 | } | |
312 | ||
313 | vmod=0; | |
314 | for(j=0;j<3;j++) vmod+=e1[j]*e1[j]; | |
315 | vmod=TMath::Sqrt(1/vmod); | |
316 | for(j=0;j<3;j++) e1[j]*=vmod; | |
317 | ||
318 | vmod=0; | |
319 | for(j=0;j<3;j++) vmod+=e2[j]*e2[j]; | |
320 | vmod=TMath::Sqrt(1/vmod); | |
321 | for(j=0;j<3;j++) e2[j]*=vmod; | |
322 | ||
323 | gMC->Rndm(ranf, 1); | |
324 | phi = ranf[0] * 2 * TMath::Pi(); | |
325 | for(j=0;j<3;j++) pol[j]=e1[j]*TMath::Sin(phi)+e2[j]*TMath::Cos(phi); | |
326 | gMC->Gdtom(pol, pol, 2); | |
327 | ||
328 | // Put photon on the stack and label it as feedback (51, 52) | |
329 | ++sNfeed; | |
330 | if (ipart == 50000050 && ifeed != 50000052) { | |
331 | weight = 5000; | |
332 | } else { | |
333 | weight = 5000; | |
334 | } | |
335 | gAlice->SetTrack(1, gAlice->CurrentTrack(), gMC->PDGFromId(50), | |
336 | mom,source,pol,position[3], | |
337 | "Cherenkov", nt, weight); | |
338 | } | |
f91473f6 | 339 | return(sNfeed); |
ddae0931 | 340 | } |