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: G4RPGNeutronInelastic.cc,v 1.4 2008/05/05 21:21:55 dennis Exp $ |
---|
27 | // GEANT4 tag $Name: geant4-09-03 $ |
---|
28 | // |
---|
29 | |
---|
30 | #include "G4RPGNeutronInelastic.hh" |
---|
31 | #include "Randomize.hh" |
---|
32 | |
---|
33 | |
---|
34 | G4HadFinalState* |
---|
35 | G4RPGNeutronInelastic::ApplyYourself(const G4HadProjectile& aTrack, |
---|
36 | G4Nucleus& targetNucleus) |
---|
37 | { |
---|
38 | theParticleChange.Clear(); |
---|
39 | const G4HadProjectile* originalIncident = &aTrack; |
---|
40 | |
---|
41 | // |
---|
42 | // create the target particle |
---|
43 | // |
---|
44 | G4DynamicParticle* originalTarget = targetNucleus.ReturnTargetParticle(); |
---|
45 | |
---|
46 | G4ReactionProduct modifiedOriginal; |
---|
47 | modifiedOriginal = *originalIncident; |
---|
48 | G4ReactionProduct targetParticle; |
---|
49 | targetParticle = *originalTarget; |
---|
50 | if( originalIncident->GetKineticEnergy()/GeV < 0.01 + 2.*G4UniformRand()/9. ) |
---|
51 | { |
---|
52 | SlowNeutron(originalIncident,modifiedOriginal,targetParticle,targetNucleus ); |
---|
53 | delete originalTarget; |
---|
54 | return &theParticleChange; |
---|
55 | } |
---|
56 | |
---|
57 | // |
---|
58 | // Fermi motion and evaporation |
---|
59 | // As of Geant3, the Fermi energy calculation had not been Done |
---|
60 | // |
---|
61 | G4double ek = originalIncident->GetKineticEnergy()/MeV; |
---|
62 | G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
---|
63 | |
---|
64 | G4double tkin = targetNucleus.Cinema( ek ); |
---|
65 | ek += tkin; |
---|
66 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
---|
67 | G4double et = ek + amas; |
---|
68 | G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
---|
69 | G4double pp = modifiedOriginal.GetMomentum().mag()/MeV; |
---|
70 | if( pp > 0.0 ) |
---|
71 | { |
---|
72 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
---|
73 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
---|
74 | } |
---|
75 | // |
---|
76 | // calculate black track energies |
---|
77 | // |
---|
78 | tkin = targetNucleus.EvaporationEffects( ek ); |
---|
79 | ek -= tkin; |
---|
80 | modifiedOriginal.SetKineticEnergy(ek); |
---|
81 | et = ek + amas; |
---|
82 | p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
---|
83 | pp = modifiedOriginal.GetMomentum().mag(); |
---|
84 | if( pp > 0.0 ) |
---|
85 | { |
---|
86 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
---|
87 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
---|
88 | } |
---|
89 | const G4double cutOff = 0.1; |
---|
90 | if( modifiedOriginal.GetKineticEnergy()/MeV <= cutOff ) |
---|
91 | { |
---|
92 | SlowNeutron( originalIncident, modifiedOriginal, targetParticle, targetNucleus ); |
---|
93 | delete originalTarget; |
---|
94 | return &theParticleChange; |
---|
95 | } |
---|
96 | |
---|
97 | G4ReactionProduct currentParticle = modifiedOriginal; |
---|
98 | currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere |
---|
99 | targetParticle.SetSide( -1 ); // target always goes in backward hemisphere |
---|
100 | G4bool incidentHasChanged = false; |
---|
101 | G4bool targetHasChanged = false; |
---|
102 | G4bool quasiElastic = false; |
---|
103 | G4FastVector<G4ReactionProduct,256> vec; // vec will contain sec. particles |
---|
104 | G4int vecLen = 0; |
---|
105 | vec.Initialize( 0 ); |
---|
106 | |
---|
107 | InitialCollision(vec, vecLen, currentParticle, targetParticle, |
---|
108 | incidentHasChanged, targetHasChanged); |
---|
109 | |
---|
110 | CalculateMomenta(vec, vecLen, |
---|
111 | originalIncident, originalTarget, modifiedOriginal, |
---|
112 | targetNucleus, currentParticle, targetParticle, |
---|
113 | incidentHasChanged, targetHasChanged, quasiElastic); |
---|
114 | |
---|
115 | SetUpChange(vec, vecLen, |
---|
116 | currentParticle, targetParticle, |
---|
117 | incidentHasChanged); |
---|
118 | |
---|
119 | delete originalTarget; |
---|
120 | return &theParticleChange; |
---|
121 | } |
---|
122 | |
---|
123 | void |
---|
124 | G4RPGNeutronInelastic::SlowNeutron(const G4HadProjectile* originalIncident, |
---|
125 | G4ReactionProduct& modifiedOriginal, |
---|
126 | G4ReactionProduct& targetParticle, |
---|
127 | G4Nucleus& targetNucleus) |
---|
128 | { |
---|
129 | const G4double A = targetNucleus.GetN(); // atomic weight |
---|
130 | const G4double Z = targetNucleus.GetZ(); // atomic number |
---|
131 | |
---|
132 | G4double currentKinetic = modifiedOriginal.GetKineticEnergy()/MeV; |
---|
133 | G4double currentMass = modifiedOriginal.GetMass()/MeV; |
---|
134 | if( A < 1.5 ) // Hydrogen |
---|
135 | { |
---|
136 | // |
---|
137 | // very simple simulation of scattering angle and energy |
---|
138 | // nonrelativistic approximation with isotropic angular |
---|
139 | // distribution in the cms system |
---|
140 | // |
---|
141 | G4double cost1, eka = 0.0; |
---|
142 | while (eka <= 0.0) |
---|
143 | { |
---|
144 | cost1 = -1.0 + 2.0*G4UniformRand(); |
---|
145 | eka = 1.0 + 2.0*cost1*A + A*A; |
---|
146 | } |
---|
147 | G4double cost = std::min( 1.0, std::max( -1.0, (A*cost1+1.0)/std::sqrt(eka) ) ); |
---|
148 | eka /= (1.0+A)*(1.0+A); |
---|
149 | G4double ek = currentKinetic*MeV/GeV; |
---|
150 | G4double amas = currentMass*MeV/GeV; |
---|
151 | ek *= eka; |
---|
152 | G4double en = ek + amas; |
---|
153 | G4double p = std::sqrt(std::abs(en*en-amas*amas)); |
---|
154 | G4double sint = std::sqrt(std::abs(1.0-cost*cost)); |
---|
155 | G4double phi = G4UniformRand()*twopi; |
---|
156 | G4double px = sint*std::sin(phi); |
---|
157 | G4double py = sint*std::cos(phi); |
---|
158 | G4double pz = cost; |
---|
159 | targetParticle.SetMomentum( px*GeV, py*GeV, pz*GeV ); |
---|
160 | G4double pxO = originalIncident->Get4Momentum().x()/GeV; |
---|
161 | G4double pyO = originalIncident->Get4Momentum().y()/GeV; |
---|
162 | G4double pzO = originalIncident->Get4Momentum().z()/GeV; |
---|
163 | G4double ptO = pxO*pxO + pyO+pyO; |
---|
164 | if( ptO > 0.0 ) |
---|
165 | { |
---|
166 | G4double pO = std::sqrt(pxO*pxO+pyO*pyO+pzO*pzO); |
---|
167 | cost = pzO/pO; |
---|
168 | sint = 0.5*(std::sqrt(std::abs((1.0-cost)*(1.0+cost)))+std::sqrt(ptO)/pO); |
---|
169 | G4double ph = pi/2.0; |
---|
170 | if( pyO < 0.0 )ph = ph*1.5; |
---|
171 | if( std::abs(pxO) > 0.000001 )ph = std::atan2(pyO,pxO); |
---|
172 | G4double cosp = std::cos(ph); |
---|
173 | G4double sinp = std::sin(ph); |
---|
174 | px = cost*cosp*px - sinp*py+sint*cosp*pz; |
---|
175 | py = cost*sinp*px + cosp*py+sint*sinp*pz; |
---|
176 | pz = -sint*px + cost*pz; |
---|
177 | } |
---|
178 | else |
---|
179 | { |
---|
180 | if( pz < 0.0 )pz *= -1.0; |
---|
181 | } |
---|
182 | G4double pu = std::sqrt(px*px+py*py+pz*pz); |
---|
183 | modifiedOriginal.SetMomentum( targetParticle.GetMomentum() * (p/pu) ); |
---|
184 | modifiedOriginal.SetKineticEnergy( ek*GeV ); |
---|
185 | |
---|
186 | targetParticle.SetMomentum( |
---|
187 | originalIncident->Get4Momentum().vect() - modifiedOriginal.GetMomentum() ); |
---|
188 | G4double pp = targetParticle.GetMomentum().mag(); |
---|
189 | G4double tarmas = targetParticle.GetMass(); |
---|
190 | targetParticle.SetTotalEnergy( std::sqrt( pp*pp + tarmas*tarmas ) ); |
---|
191 | |
---|
192 | theParticleChange.SetEnergyChange( modifiedOriginal.GetKineticEnergy() ); |
---|
193 | G4DynamicParticle *pd = new G4DynamicParticle; |
---|
194 | pd->SetDefinition( targetParticle.GetDefinition() ); |
---|
195 | pd->SetMomentum( targetParticle.GetMomentum() ); |
---|
196 | theParticleChange.AddSecondary( pd ); |
---|
197 | return; |
---|
198 | } |
---|
199 | |
---|
200 | G4FastVector<G4ReactionProduct,4> vec; // vec will contain the secondary particles |
---|
201 | G4int vecLen = 0; |
---|
202 | vec.Initialize( 0 ); |
---|
203 | |
---|
204 | G4double theAtomicMass = targetNucleus.AtomicMass( A, Z ); |
---|
205 | G4double massVec[9]; |
---|
206 | massVec[0] = targetNucleus.AtomicMass( A+1.0, Z ); |
---|
207 | massVec[1] = theAtomicMass; |
---|
208 | massVec[2] = 0.; |
---|
209 | if (Z > 1.0) massVec[2] = targetNucleus.AtomicMass(A, Z-1.0); |
---|
210 | massVec[3] = 0.; |
---|
211 | if (Z > 1.0 && A > 1.0) massVec[3] = targetNucleus.AtomicMass(A-1.0, Z-1.0 ); |
---|
212 | massVec[4] = 0.; |
---|
213 | if (Z > 1.0 && A > 2.0 && A-2.0 > Z-1.0) |
---|
214 | massVec[4] = targetNucleus.AtomicMass( A-2.0, Z-1.0 ); |
---|
215 | massVec[5] = 0.; |
---|
216 | if (Z > 2.0 && A > 3.0 && A-3.0 > Z-2.0) |
---|
217 | massVec[5] = targetNucleus.AtomicMass( A-3.0, Z-2.0 ); |
---|
218 | massVec[6] = 0.; |
---|
219 | if (A > 1.0 && A-1.0 > Z) massVec[6] = targetNucleus.AtomicMass(A-1.0, Z); |
---|
220 | massVec[7] = massVec[3]; |
---|
221 | massVec[8] = 0.; |
---|
222 | if (Z > 2.0 && A > 1.0) massVec[8] = targetNucleus.AtomicMass( A-1.0,Z-2.0 ); |
---|
223 | |
---|
224 | twoBody.NuclearReaction(vec, vecLen, originalIncident, |
---|
225 | targetNucleus, theAtomicMass, massVec ); |
---|
226 | |
---|
227 | theParticleChange.SetStatusChange( stopAndKill ); |
---|
228 | theParticleChange.SetEnergyChange( 0.0 ); |
---|
229 | |
---|
230 | G4DynamicParticle* pd; |
---|
231 | for( G4int i=0; i<vecLen; ++i ) { |
---|
232 | pd = new G4DynamicParticle(); |
---|
233 | pd->SetDefinition( vec[i]->GetDefinition() ); |
---|
234 | pd->SetMomentum( vec[i]->GetMomentum() ); |
---|
235 | theParticleChange.AddSecondary( pd ); |
---|
236 | delete vec[i]; |
---|
237 | } |
---|
238 | } |
---|
239 | |
---|
240 | |
---|
241 | // Initial Collision |
---|
242 | // selects the particle types arising from the initial collision of |
---|
243 | // the neutron and target nucleon. Secondaries are assigned to |
---|
244 | // forward and backward reaction hemispheres, but final state energies |
---|
245 | // and momenta are not calculated here. |
---|
246 | |
---|
247 | void |
---|
248 | G4RPGNeutronInelastic::InitialCollision(G4FastVector<G4ReactionProduct,256>& vec, |
---|
249 | G4int& vecLen, |
---|
250 | G4ReactionProduct& currentParticle, |
---|
251 | G4ReactionProduct& targetParticle, |
---|
252 | G4bool& incidentHasChanged, |
---|
253 | G4bool& targetHasChanged) |
---|
254 | { |
---|
255 | G4double KE = currentParticle.GetKineticEnergy()/GeV; |
---|
256 | |
---|
257 | G4int mult; |
---|
258 | G4int partType; |
---|
259 | std::vector<G4int> fsTypes; |
---|
260 | G4int part1; |
---|
261 | G4int part2; |
---|
262 | |
---|
263 | G4double testCharge; |
---|
264 | G4double testBaryon; |
---|
265 | G4double testStrange; |
---|
266 | |
---|
267 | // Get particle types according to incident and target types |
---|
268 | |
---|
269 | if (targetParticle.GetDefinition() == particleDef[neu]) { |
---|
270 | mult = GetMultiplicityT1(KE); |
---|
271 | fsTypes = GetFSPartTypesForNN(mult, KE); |
---|
272 | |
---|
273 | part1 = fsTypes[0]; |
---|
274 | part2 = fsTypes[1]; |
---|
275 | currentParticle.SetDefinition(particleDef[part1]); |
---|
276 | targetParticle.SetDefinition(particleDef[part2]); |
---|
277 | if (part1 == pro) { |
---|
278 | if (part2 == neu) { |
---|
279 | if (G4UniformRand() > 0.5) { |
---|
280 | incidentHasChanged = true; |
---|
281 | } else { |
---|
282 | targetHasChanged = true; |
---|
283 | currentParticle.SetDefinition(particleDef[part2]); |
---|
284 | targetParticle.SetDefinition(particleDef[part1]); |
---|
285 | } |
---|
286 | } else { |
---|
287 | targetHasChanged = true; |
---|
288 | incidentHasChanged = true; |
---|
289 | } |
---|
290 | |
---|
291 | } else { // neutron |
---|
292 | if (part2 > neu && part2 < xi0) targetHasChanged = true; |
---|
293 | } |
---|
294 | |
---|
295 | testCharge = 0.0; |
---|
296 | testBaryon = 2.0; |
---|
297 | testStrange = 0.0; |
---|
298 | |
---|
299 | } else { // target was a proton |
---|
300 | mult = GetMultiplicityT0(KE); |
---|
301 | fsTypes = GetFSPartTypesForNP(mult, KE); |
---|
302 | |
---|
303 | part1 = fsTypes[0]; |
---|
304 | part2 = fsTypes[1]; |
---|
305 | currentParticle.SetDefinition(particleDef[part1]); |
---|
306 | targetParticle.SetDefinition(particleDef[part2]); |
---|
307 | if (part1 == pro) { |
---|
308 | if (part2 == pro) { |
---|
309 | incidentHasChanged = true; |
---|
310 | } else if (part2 == neu) { |
---|
311 | if (G4UniformRand() > 0.5) { |
---|
312 | incidentHasChanged = true; |
---|
313 | targetHasChanged = true; |
---|
314 | } else { |
---|
315 | currentParticle.SetDefinition(particleDef[part2]); |
---|
316 | targetParticle.SetDefinition(particleDef[part1]); |
---|
317 | } |
---|
318 | |
---|
319 | } else if (part2 > neu && part2 < xi0) { |
---|
320 | incidentHasChanged = true; |
---|
321 | targetHasChanged = true; |
---|
322 | } |
---|
323 | |
---|
324 | } else { // neutron |
---|
325 | targetHasChanged = true; |
---|
326 | } |
---|
327 | |
---|
328 | testCharge = 1.0; |
---|
329 | testBaryon = 2.0; |
---|
330 | testStrange = 0.0; |
---|
331 | } |
---|
332 | |
---|
333 | // if (mult == 2 && !incidentHasChanged && !targetHasChanged) |
---|
334 | // quasiElastic = true; |
---|
335 | |
---|
336 | // Remove incident and target from fsTypes |
---|
337 | |
---|
338 | fsTypes.erase(fsTypes.begin()); |
---|
339 | fsTypes.erase(fsTypes.begin()); |
---|
340 | |
---|
341 | // Remaining particles are secondaries. Put them into vec. |
---|
342 | |
---|
343 | G4ReactionProduct* rp(0); |
---|
344 | for(G4int i=0; i < mult-2; ++i ) { |
---|
345 | partType = fsTypes[i]; |
---|
346 | rp = new G4ReactionProduct(); |
---|
347 | rp->SetDefinition(particleDef[partType]); |
---|
348 | (G4UniformRand() < 0.5) ? rp->SetSide(-1) : rp->SetSide(1); |
---|
349 | vec.SetElement(vecLen++, rp); |
---|
350 | } |
---|
351 | |
---|
352 | // Check conservation of charge, strangeness, baryon number |
---|
353 | |
---|
354 | CheckQnums(vec, vecLen, currentParticle, targetParticle, |
---|
355 | testCharge, testBaryon, testStrange); |
---|
356 | |
---|
357 | return; |
---|
358 | } |
---|