1 | // |
---|
2 | // ******************************************************************** |
---|
3 | // * License and Disclaimer * |
---|
4 | // * * |
---|
5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
7 | // * conditions of the Geant4 Software License, included in the file * |
---|
8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
9 | // * include a list of copyright holders. * |
---|
10 | // * * |
---|
11 | // * Neither the authors of this software system, nor their employing * |
---|
12 | // * institutes,nor the agencies providing financial support for this * |
---|
13 | // * work make any representation or warranty, express or implied, * |
---|
14 | // * regarding this software system or assume any liability for its * |
---|
15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
16 | // * for the full disclaimer and the limitation of liability. * |
---|
17 | // * * |
---|
18 | // * This code implementation is the result of the scientific and * |
---|
19 | // * technical work of the GEANT4 collaboration. * |
---|
20 | // * By using, copying, modifying or distributing the software (or * |
---|
21 | // * any work based on the software) you agree to acknowledge its * |
---|
22 | // * use in resulting scientific publications, and indicate your * |
---|
23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
24 | // ******************************************************************** |
---|
25 | // |
---|
26 | // $Id: G4RPGPiPlusInelastic.cc,v 1.4 2008/05/05 21:21:55 dennis Exp $ |
---|
27 | // GEANT4 tag $Name: geant4-09-03-ref-09 $ |
---|
28 | // |
---|
29 | |
---|
30 | #include "G4RPGPiPlusInelastic.hh" |
---|
31 | #include "Randomize.hh" |
---|
32 | |
---|
33 | G4HadFinalState* |
---|
34 | G4RPGPiPlusInelastic::ApplyYourself(const G4HadProjectile& aTrack, |
---|
35 | G4Nucleus& targetNucleus) |
---|
36 | { |
---|
37 | const G4HadProjectile *originalIncident = &aTrack; |
---|
38 | if (originalIncident->GetKineticEnergy()<= 0.1) { |
---|
39 | theParticleChange.SetStatusChange(isAlive); |
---|
40 | theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy()); |
---|
41 | theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit()); |
---|
42 | return &theParticleChange; |
---|
43 | } |
---|
44 | |
---|
45 | // create the target particle |
---|
46 | |
---|
47 | G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle(); |
---|
48 | G4ReactionProduct targetParticle( originalTarget->GetDefinition() ); |
---|
49 | |
---|
50 | G4ReactionProduct currentParticle( |
---|
51 | const_cast<G4ParticleDefinition *>(originalIncident->GetDefinition() ) ); |
---|
52 | currentParticle.SetMomentum( originalIncident->Get4Momentum().vect() ); |
---|
53 | currentParticle.SetKineticEnergy( originalIncident->GetKineticEnergy() ); |
---|
54 | |
---|
55 | // Fermi motion and evaporation |
---|
56 | // As of Geant3, the Fermi energy calculation had not been Done |
---|
57 | |
---|
58 | G4double ek = originalIncident->GetKineticEnergy(); |
---|
59 | G4double amas = originalIncident->GetDefinition()->GetPDGMass(); |
---|
60 | |
---|
61 | G4double tkin = targetNucleus.Cinema( ek ); |
---|
62 | ek += tkin; |
---|
63 | currentParticle.SetKineticEnergy( ek ); |
---|
64 | G4double et = ek + amas; |
---|
65 | G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
---|
66 | G4double pp = currentParticle.GetMomentum().mag(); |
---|
67 | if( pp > 0.0 ) |
---|
68 | { |
---|
69 | G4ThreeVector momentum = currentParticle.GetMomentum(); |
---|
70 | currentParticle.SetMomentum( momentum * (p/pp) ); |
---|
71 | } |
---|
72 | |
---|
73 | // calculate black track energies |
---|
74 | |
---|
75 | tkin = targetNucleus.EvaporationEffects( ek ); |
---|
76 | ek -= tkin; |
---|
77 | currentParticle.SetKineticEnergy( ek ); |
---|
78 | et = ek + amas; |
---|
79 | p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
---|
80 | pp = currentParticle.GetMomentum().mag(); |
---|
81 | if( pp > 0.0 ) |
---|
82 | { |
---|
83 | G4ThreeVector momentum = currentParticle.GetMomentum(); |
---|
84 | currentParticle.SetMomentum( momentum * (p/pp) ); |
---|
85 | } |
---|
86 | |
---|
87 | G4ReactionProduct modifiedOriginal = currentParticle; |
---|
88 | |
---|
89 | currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere |
---|
90 | targetParticle.SetSide( -1 ); // target always goes in backward hemisphere |
---|
91 | G4bool incidentHasChanged = false; |
---|
92 | G4bool targetHasChanged = false; |
---|
93 | G4bool quasiElastic = false; |
---|
94 | G4FastVector<G4ReactionProduct,256> vec; // vec will contain the secondary particles |
---|
95 | G4int vecLen = 0; |
---|
96 | vec.Initialize( 0 ); |
---|
97 | |
---|
98 | const G4double cutOff = 0.1; |
---|
99 | if( currentParticle.GetKineticEnergy() > cutOff ) |
---|
100 | InitialCollision(vec, vecLen, currentParticle, targetParticle, |
---|
101 | incidentHasChanged, targetHasChanged); |
---|
102 | |
---|
103 | CalculateMomenta( vec, vecLen, |
---|
104 | originalIncident, originalTarget, modifiedOriginal, |
---|
105 | targetNucleus, currentParticle, targetParticle, |
---|
106 | incidentHasChanged, targetHasChanged, quasiElastic ); |
---|
107 | |
---|
108 | SetUpChange( vec, vecLen, |
---|
109 | currentParticle, targetParticle, |
---|
110 | incidentHasChanged ); |
---|
111 | |
---|
112 | delete originalTarget; |
---|
113 | return &theParticleChange; |
---|
114 | } |
---|
115 | |
---|
116 | |
---|
117 | // Initial Collision |
---|
118 | // selects the particle types arising from the initial collision of |
---|
119 | // the projectile and target nucleon. Secondaries are assigned to |
---|
120 | // forward and backward reaction hemispheres, but final state energies |
---|
121 | // and momenta are not calculated here. |
---|
122 | |
---|
123 | void |
---|
124 | G4RPGPiPlusInelastic::InitialCollision(G4FastVector<G4ReactionProduct,256>& vec, |
---|
125 | G4int& vecLen, |
---|
126 | G4ReactionProduct& currentParticle, |
---|
127 | G4ReactionProduct& targetParticle, |
---|
128 | G4bool& incidentHasChanged, |
---|
129 | G4bool& targetHasChanged) |
---|
130 | { |
---|
131 | G4double KE = currentParticle.GetKineticEnergy()/GeV; |
---|
132 | |
---|
133 | G4int mult; |
---|
134 | G4int partType; |
---|
135 | std::vector<G4int> fsTypes; |
---|
136 | |
---|
137 | G4double testCharge; |
---|
138 | G4double testBaryon; |
---|
139 | G4double testStrange; |
---|
140 | |
---|
141 | // Get particle types according to incident and target types |
---|
142 | |
---|
143 | if (targetParticle.GetDefinition() == particleDef[pro]) { |
---|
144 | mult = GetMultiplicityT32(KE); |
---|
145 | fsTypes = GetFSPartTypesForPipP(mult, KE); |
---|
146 | partType = fsTypes[0]; |
---|
147 | if (partType != pro) { |
---|
148 | targetHasChanged = true; |
---|
149 | targetParticle.SetDefinition(particleDef[partType]); |
---|
150 | } |
---|
151 | |
---|
152 | testCharge = 2.0; |
---|
153 | testBaryon = 1.0; |
---|
154 | testStrange = 0.0; |
---|
155 | |
---|
156 | } else { // target was a neutron |
---|
157 | mult = GetMultiplicityT12(KE); |
---|
158 | fsTypes = GetFSPartTypesForPipN(mult, KE); |
---|
159 | partType = fsTypes[0]; |
---|
160 | if (partType != neu) { |
---|
161 | targetHasChanged = true; |
---|
162 | targetParticle.SetDefinition(particleDef[partType]); |
---|
163 | } |
---|
164 | |
---|
165 | testCharge = 1.0; |
---|
166 | testBaryon = 1.0; |
---|
167 | testStrange = 0.0; |
---|
168 | } |
---|
169 | |
---|
170 | // Remove target particle from list |
---|
171 | |
---|
172 | fsTypes.erase(fsTypes.begin()); |
---|
173 | |
---|
174 | // See if the incident particle changed type |
---|
175 | |
---|
176 | G4int choose = -1; |
---|
177 | for(G4int i=0; i < mult-1; ++i ) { |
---|
178 | partType = fsTypes[i]; |
---|
179 | if (partType == pip) { |
---|
180 | choose = i; |
---|
181 | break; |
---|
182 | } |
---|
183 | } |
---|
184 | if (choose == -1) { |
---|
185 | incidentHasChanged = true; |
---|
186 | choose = G4int(G4UniformRand()*(mult-1) ); |
---|
187 | partType = fsTypes[choose]; |
---|
188 | currentParticle.SetDefinition(particleDef[partType]); |
---|
189 | } |
---|
190 | fsTypes.erase(fsTypes.begin()+choose); |
---|
191 | |
---|
192 | // Remaining particles are secondaries. Put them into vec. |
---|
193 | // Improve this by randomizing secondary order, then alternate |
---|
194 | // which secondary is put into forward or backward hemisphere |
---|
195 | |
---|
196 | G4ReactionProduct* rp(0); |
---|
197 | for(G4int i=0; i < mult-2; ++i ) { |
---|
198 | partType = fsTypes[i]; |
---|
199 | rp = new G4ReactionProduct(); |
---|
200 | rp->SetDefinition(particleDef[partType]); |
---|
201 | (G4UniformRand() < 0.5) ? rp->SetSide(-1) : rp->SetSide(1); |
---|
202 | if (partType > pim && partType < pro) rp->SetMayBeKilled(false); // kaons |
---|
203 | vec.SetElement(vecLen++, rp); |
---|
204 | } |
---|
205 | |
---|
206 | // if (mult == 2 && !incidentHasChanged && !targetHasChanged) |
---|
207 | // quasiElastic = true; |
---|
208 | |
---|
209 | // Check conservation of charge, strangeness, baryon number |
---|
210 | |
---|
211 | CheckQnums(vec, vecLen, currentParticle, targetParticle, |
---|
212 | testCharge, testBaryon, testStrange); |
---|
213 | |
---|
214 | return; |
---|
215 | } |
---|