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e3bd319d | 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 | /* $Id$ */ | |
17 | ||
18 | ||
19 | ||
20 | //------------------------------------------------------------- | |
21 | // Generate Beam-Gas-Events | |
22 | // Default: underlying event: pO @ 7 TeV (fixed target) | |
23 | // | |
24 | // underlying event can be changed by adding generators | |
25 | // in the same way as to AliGenCocktail before calling | |
26 | // the Init() | |
27 | // Author: Jochen Klein | |
28 | //------------------------------------------------------------- | |
29 | ||
30 | #include "AliGenBeamGasNew.h" | |
31 | #include "AliGenCocktail.h" | |
32 | #include "AliGenCocktailEntry.h" | |
33 | #include "AliGenEventHeader.h" | |
34 | #include "AliGenCocktailEventHeader.h" | |
35 | #include "AliGenHijing.h" | |
36 | #include <TList.h> | |
37 | #include <TObjArray.h> | |
38 | #include "AliCollisionGeometry.h" | |
39 | #include "AliRun.h" | |
40 | #include "AliMC.h" | |
41 | #include "AliStack.h" | |
42 | #include "AliHeader.h" | |
43 | #include "TParticle.h" | |
44 | ||
45 | ClassImp(AliGenBeamGasNew) | |
46 | ||
47 | Float_t EtaToTheta(Float_t arg) { return (180./TMath::Pi())*2.*atan(exp(-arg)); } | |
48 | ||
49 | AliGenBeamGasNew::AliGenBeamGasNew() : | |
50 | AliGenCocktail(), | |
51 | fItime(0), | |
52 | fTwindow(88e-6), | |
53 | fZwindow(2000), | |
54 | fRate(1e3) | |
55 | { | |
56 | printf("AliGenBeamGasNew instatiated!\n"); | |
57 | } | |
58 | ||
59 | AliGenBeamGasNew::~AliGenBeamGasNew() | |
60 | { | |
61 | delete fEntries; | |
62 | fEntries = 0; | |
63 | fHeader = 0; | |
64 | } | |
65 | ||
66 | void AliGenBeamGasNew::SetTimeWindow(Float_t twindow) { fTwindow = twindow; } | |
67 | ||
68 | bool AliGenBeamGasNew::SetRate(Float_t rate) { | |
69 | if (rate >= 0) { | |
70 | fRate = rate; | |
71 | return true; | |
72 | } else | |
73 | return false; | |
74 | } | |
75 | ||
76 | void AliGenBeamGasNew::SetZWindow(Float_t zwindow) { fZwindow = zwindow; } | |
77 | ||
78 | void AliGenBeamGasNew::Init() | |
79 | { | |
80 | // Initialisation of the class | |
81 | // if no generators were added before calling Init() | |
82 | // AliGenHijing is added configured for pO | |
83 | ||
84 | fVertexSmear = kPerEvent; | |
85 | fVertexSource = kInternal; | |
86 | fRandom = kTRUE; | |
87 | ||
88 | // Adding default underlying event in case none was specified | |
89 | // p-O-collision at 7 TeV (fixed target) | |
90 | if (!fEntries) { | |
91 | AliGenHijing *gen = new AliGenHijing(-1); | |
92 | gen->SetEnergyCMS(7000); | |
93 | gen->SetReferenceFrame("LAB"); | |
94 | gen->SetProjectile("P",1,1); | |
95 | gen->SetTarget("A",16,8); | |
96 | gen->SetPhiRange(0,360); | |
97 | Float_t thmin = EtaToTheta(8); | |
98 | Float_t thmax = EtaToTheta(-8); | |
99 | gen->SetThetaRange(thmin, thmax); | |
100 | gen->SetOrigin(0,0,0); | |
101 | gen->SetSigma(0,0,0); | |
102 | gen->KeepFullEvent(); | |
103 | gen->SetShadowing(1); | |
104 | gen->SetDecaysOff(1); | |
105 | gen->SetSpectators(1); | |
106 | gen->SetSelectAll(1); | |
107 | gen->SetRandomPz(kFALSE); | |
108 | gen->SetPileUpTimeWindow(0.); | |
109 | AddGenerator(gen,"Hijing pO",1); | |
110 | } | |
111 | ||
112 | TIter next(fEntries); | |
113 | AliGenCocktailEntry *entry; | |
114 | ||
115 | // Loop over generators and initialize | |
116 | while((entry = (AliGenCocktailEntry*)next())) { | |
117 | if (fStack) entry->Generator()->SetStack(fStack); | |
118 | entry->Generator()->Init(); | |
119 | } | |
120 | ||
121 | next.Reset(); | |
122 | ||
123 | if (fRandom) { | |
124 | fProb.Set(fNGenerators); | |
125 | next.Reset(); | |
126 | Float_t sum = 0.; | |
127 | while((entry = (AliGenCocktailEntry*)next())) { | |
128 | sum += entry->Rate(); | |
129 | } | |
130 | ||
131 | next.Reset(); | |
132 | Int_t i = 0; | |
133 | Float_t psum = 0.; | |
134 | while((entry = (AliGenCocktailEntry*)next())) { | |
135 | psum += entry->Rate() / sum; | |
136 | fProb[i++] = psum; | |
137 | } | |
138 | } | |
139 | next.Reset(); | |
140 | } | |
141 | ||
142 | void AliGenBeamGasNew::VertexInternal() | |
143 | { | |
144 | // calculation of the interaction vertex for the beam gas event | |
145 | // both spatial and time coordinate are adjusted. | |
146 | ||
147 | Float_t random[2]; | |
148 | Float_t nbunch; | |
149 | Float_t bunch; | |
150 | ||
151 | gRandom->RndmArray(2,random); | |
152 | fVertex[0] = fVertex[1] = 0; | |
153 | fVertex[2] = random[0] * 4000 - 2000; | |
154 | nbunch = fTwindow/25e-9; | |
155 | bunch = floor(2*nbunch * random[1] - nbunch); | |
156 | fItime = fVertex[2] / 100 / 3e8 + bunch * 25e-9; | |
157 | } | |
158 | ||
159 | void AliGenBeamGasNew::Generate() | |
160 | { | |
161 | // | |
162 | // Generate the collisions for one event | |
163 | // | |
164 | Int_t numbg = gRandom->Poisson(fRate*fZwindow/100*2*fTwindow); | |
165 | if (numbg == 0) return; | |
166 | ||
167 | TIter next(fEntries); | |
168 | AliGenCocktailEntry *entry = 0; | |
169 | AliGenCocktailEntry *preventry = 0; | |
170 | AliGenerator* gen = 0; | |
171 | TLorentzVector v; | |
172 | TArrayF eventVertex; | |
173 | Int_t lastpart=0; | |
174 | Float_t sign; | |
175 | ||
176 | if (fHeader) delete fHeader; | |
177 | fHeader = new AliGenCocktailEventHeader("Beamgas Header"); | |
178 | ||
179 | TObjArray *partArray = gAlice->GetMCApp()->Particles(); | |
180 | AliStack *stack = gAlice->GetRunLoader()->Stack(); | |
181 | ||
182 | for (Int_t l = 0; l < numbg; l++) { | |
183 | Vertex(); | |
184 | sign = (gRandom->Rndm() < 0.5)? -1. : 1.; | |
185 | eventVertex.Set(3); | |
186 | for (Int_t j=0; j < 3; j++) eventVertex[j] = fVertex[j]; | |
187 | ||
188 | if (!fRandom) { | |
189 | Int_t igen=0; | |
190 | while((entry = (AliGenCocktailEntry*)next())) { | |
191 | if (fUsePerEventRate && (gRandom->Rndm() > entry->Rate())) continue; | |
192 | ||
193 | igen++; | |
194 | if (igen ==1) { | |
195 | entry->SetFirst(lastpart); | |
196 | } else { | |
197 | entry->SetFirst((partArray->GetEntriesFast())+1); | |
198 | } | |
199 | // | |
200 | // Handle case in which current generator needs collision geometry from previous generator | |
201 | // | |
202 | gen = entry->Generator(); | |
203 | if (gen->NeedsCollisionGeometry()) | |
204 | { | |
205 | if (preventry && preventry->Generator()->ProvidesCollisionGeometry()) | |
206 | { | |
207 | gen->SetCollisionGeometry(preventry->Generator()->CollisionGeometry()); | |
208 | } else { | |
209 | Fatal("Generate()", "No Collision Geometry Provided"); | |
210 | } | |
211 | } | |
212 | entry->Generator()->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2)); | |
213 | entry->Generator()->Generate(); | |
214 | entry->SetLast(partArray->GetEntriesFast()); | |
215 | preventry = entry; | |
216 | } | |
217 | } else { | |
218 | // | |
219 | // Select a generator randomly | |
220 | // | |
221 | Int_t i; | |
222 | Float_t p0 = gRandom->Rndm(); | |
223 | ||
224 | for (i = 0; i < fNGenerators; i++) { | |
225 | if (p0 < fProb[i]) break; | |
226 | } | |
227 | ||
228 | entry = (AliGenCocktailEntry*) fEntries->At(i); | |
229 | entry->SetFirst(lastpart); | |
230 | gen = entry->Generator(); | |
231 | entry->Generator()->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2)); | |
232 | entry->Generator()->Generate(); | |
233 | entry->SetLast(partArray->GetEntriesFast()); | |
234 | } | |
235 | ||
236 | for (int k = lastpart; k < stack->GetNprimary(); k++) { | |
237 | stack->Particle(k)->ProductionVertex(v); | |
238 | v[2] *= sign; | |
239 | v[3] = fItime; // ??? += | |
240 | stack->Particle(k)->SetProductionVertex(v); | |
241 | stack->Particle(k)->Momentum(v); | |
242 | v[2] *= sign; | |
243 | stack->Particle(k)->SetMomentum(v); | |
244 | } | |
245 | ||
246 | lastpart = stack->GetNprimary(); | |
247 | next.Reset(); | |
248 | } | |
249 | // Event Vertex | |
250 | fHeader->SetPrimaryVertex(eventVertex); | |
251 | // fHeader->SetNvertex(numbg); | |
252 | if (fContainer) { | |
253 | fContainer->AddHeader(fHeader); | |
254 | } else { | |
255 | gAlice->SetGenEventHeader(fHeader); | |
256 | } | |
257 | } |