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25 //
26
27 // G4 Low energy model: n-p scattering
28 // F.W. Jones, L.G. Greeniaus, H.P. Wellisch
29
30 // 11-OCT-2007 F.W. Jones: removed erroneous code for identity
31 // exchange of particles.
32 // FWJ 27-AUG-2010: extended to 5 GeV by Tony Kwan TRIUMF
33
34 #include "G4LEnp.hh"
35 #include "G4PhysicalConstants.hh"
36 #include "G4SystemOfUnits.hh"
37 #include "Randomize.hh"
38 #include "G4ios.hh"
39
40 // Initialization of static data arrays:
41 #include "G4LEnpData.hh"
42 #include "Randomize.hh"
43
44 #include "G4PhysicsModelCatalog.hh"
45
46
47 G4LEnp::G4LEnp():
48 G4HadronElastic("G4LEnp") // G4HadronicInteraction("G4LEnp")
49 {
50 secID = G4PhysicsModelCatalog::GetModelID( "model_" + GetModelName() );
51 // theParticleChange.SetNumberOfSecondaries(1);
52
53 // SetMinEnergy(10.*MeV);
54 // SetMaxEnergy(1200.*MeV);
55 SetMinEnergy(0.);
56 SetMaxEnergy(5.*GeV);
57 }
58
59 G4LEnp::~G4LEnp()
60 {
61 theParticleChange.Clear();
62 }
63
64 G4HadFinalState*
65 G4LEnp::ApplyYourself(const G4HadProjectile& aTrack, G4Nucleus& targetNucleus)
66 {
67 theParticleChange.Clear();
68 const G4HadProjectile* aParticle = &aTrack;
69
70 G4double P = aParticle->GetTotalMomentum();
71 G4double Px = aParticle->Get4Momentum().x();
72 G4double Py = aParticle->Get4Momentum().y();
73 G4double Pz = aParticle->Get4Momentum().z();
74 G4double ek = aParticle->GetKineticEnergy();
75 G4ThreeVector theInitial = aParticle->Get4Momentum().vect();
76
77 if (verboseLevel > 1) {
78 G4double E = aParticle->GetTotalEnergy();
79 G4double E0 = aParticle->GetDefinition()->GetPDGMass();
80 G4double Q = aParticle->GetDefinition()->GetPDGCharge();
81 G4int A = targetNucleus.GetA_asInt();
82 G4int Z = targetNucleus.GetZ_asInt();
83 G4cout << "G4LEnp:ApplyYourself: incident particle: "
84 << aParticle->GetDefinition()->GetParticleName() << G4endl;
85 G4cout << "P = " << P/GeV << " GeV/c"
86 << ", Px = " << Px/GeV << " GeV/c"
87 << ", Py = " << Py/GeV << " GeV/c"
88 << ", Pz = " << Pz/GeV << " GeV/c" << G4endl;
89 G4cout << "E = " << E/GeV << " GeV"
90 << ", kinetic energy = " << ek/GeV << " GeV"
91 << ", mass = " << E0/GeV << " GeV"
92 << ", charge = " << Q << G4endl;
93 G4cout << "G4LEnp:ApplyYourself: material:" << G4endl;
94 G4cout << "A = " << A
95 << ", Z = " << Z
96 << ", atomic mass "
97 << G4Proton::Proton()->GetPDGMass()/GeV << "GeV"
98 << G4endl;
99 //
100 // GHEISHA ADD operation to get total energy, mass, charge
101 //
102 E += proton_mass_c2;
103 G4double E02 = E*E - P*P;
104 E0 = std::sqrt(std::abs(E02));
105 if (E02 < 0)E0 *= -1;
106 Q += Z;
107 G4cout << "G4LEnp:ApplyYourself: total:" << G4endl;
108 G4cout << "E = " << E/GeV << " GeV"
109 << ", mass = " << E0/GeV << " GeV"
110 << ", charge = " << Q << G4endl;
111 }
112
113 // Find energy bin
114
115 G4int je1 = 0;
116 G4int je2 = NENERGY - 1;
117 ek = ek/GeV;
118 do {
119 G4int midBin = (je1 + je2)/2;
120 if (ek < elab[midBin])
121 je2 = midBin;
122 else
123 je1 = midBin;
124 } while (je2 - je1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
125 G4double delab = elab[je2] - elab[je1];
126
127 // Sample the angle
128
129 G4double sample = G4UniformRand();
130 G4int ke1 = 0;
131 G4int ke2 = NANGLE - 1;
132 G4double dsig = sig[je2][0] - sig[je1][0];
133 G4double rc = dsig/delab;
134 G4double b = sig[je1][0] - rc*elab[je1];
135 G4double sigint1 = rc*ek + b;
136 G4double sigint2 = 0.;
137
138 if (verboseLevel > 1) {
139 G4cout << "sample=" << sample << G4endl
140 << ke1 << " " << ke2 << " "
141 << sigint1 << " " << sigint2 << G4endl;
142 }
143 do {
144 G4int midBin = (ke1 + ke2)/2;
145 dsig = sig[je2][midBin] - sig[je1][midBin];
146 rc = dsig/delab;
147 b = sig[je1][midBin] - rc*elab[je1];
148 G4double sigint = rc*ek + b;
149 if (sample < sigint) {
150 ke2 = midBin;
151 sigint2 = sigint;
152 }
153 else {
154 ke1 = midBin;
155 sigint1 = sigint;
156 }
157 if (verboseLevel > 1) {
158 G4cout << ke1 << " " << ke2 << " "
159 << sigint1 << " " << sigint2 << G4endl;
160 }
161 } while (ke2 - ke1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
162
163 dsig = sigint2 - sigint1;
164 rc = 1./dsig;
165 b = ke1 - rc*sigint1;
166 G4double kint = rc*sample + b;
167 G4double theta = (0.5 + kint)*pi/180.;
168
169 if (verboseLevel > 1) {
170 G4cout << " energy bin " << je1 << " energy=" << elab[je1] << G4endl;
171 G4cout << " angle bin " << kint << " angle=" << theta/degree << G4endl;
172 }
173
174 // Get the target particle
175
176 G4DynamicParticle* targetParticle = targetNucleus.ReturnTargetParticle();
177
178 G4double E1 = aParticle->GetTotalEnergy();
179 G4double M1 = aParticle->GetDefinition()->GetPDGMass();
180 G4double E2 = targetParticle->GetTotalEnergy();
181 G4double M2 = targetParticle->GetDefinition()->GetPDGMass();
182 G4double totalEnergy = E1 + E2;
183 G4double pseudoMass = std::sqrt(totalEnergy*totalEnergy - P*P);
184
185 // Transform into centre of mass system
186
187 G4double px = (M2/pseudoMass)*Px;
188 G4double py = (M2/pseudoMass)*Py;
189 G4double pz = (M2/pseudoMass)*Pz;
190 G4double p = std::sqrt(px*px + py*py + pz*pz);
191
192 if (verboseLevel > 1) {
193 G4cout << " E1, M1 (GeV) " << E1/GeV << " " << M1/GeV << G4endl;
194 G4cout << " E2, M2 (GeV) " << E2/GeV << " " << M2/GeV << G4endl;
195 G4cout << " particle 1 momentum in CM " << px/GeV << " " << py/GeV << " "
196 << pz/GeV << " " << p/GeV << G4endl;
197 }
198
199 // First scatter w.r.t. Z axis
200 G4double phi = G4UniformRand()*twopi;
201 G4double pxnew = p*std::sin(theta)*std::cos(phi);
202 G4double pynew = p*std::sin(theta)*std::sin(phi);
203 G4double pznew = p*std::cos(theta);
204
205 // Rotate according to the direction of the incident particle
206 if (px*px + py*py > 0) {
207 G4double cost, sint, ph, cosp, sinp;
208 cost = pz/p;
209 sint = (std::sqrt(std::fabs((1-cost)*(1+cost))) + std::sqrt(px*px+py*py)/p)/2;
210 py < 0 ? ph = 3*halfpi : ph = halfpi;
211 if (std::abs(px) > 0.000001*GeV) ph = std::atan2(py,px);
212 cosp = std::cos(ph);
213 sinp = std::sin(ph);
214 px = (cost*cosp*pxnew - sinp*pynew + sint*cosp*pznew);
215 py = (cost*sinp*pxnew + cosp*pynew + sint*sinp*pznew);
216 pz = (-sint*pxnew + cost*pznew);
217 }
218 else {
219 px = pxnew;
220 py = pynew;
221 pz = pznew;
222 }
223
224 if (verboseLevel > 1) {
225 G4cout << " AFTER SCATTER..." << G4endl;
226 G4cout << " particle 1 momentum in CM " << px/GeV << " " << py/GeV << " "
227 << pz/GeV << " " << p/GeV << G4endl;
228 }
229
230 // Transform to lab system
231
232 G4double E1pM2 = E1 + M2;
233 G4double betaCM = P/E1pM2;
234 G4double betaCMx = Px/E1pM2;
235 G4double betaCMy = Py/E1pM2;
236 G4double betaCMz = Pz/E1pM2;
237 G4double gammaCM = E1pM2/std::sqrt(E1pM2*E1pM2 - P*P);
238
239 if (verboseLevel > 1) {
240 G4cout << " betaCM " << betaCMx << " " << betaCMy << " "
241 << betaCMz << " " << betaCM << G4endl;
242 G4cout << " gammaCM " << gammaCM << G4endl;
243 }
244
245 // Now following GLOREN...
246
247 G4double BETA[5], PA[5], PB[5];
248 BETA[1] = -betaCMx;
249 BETA[2] = -betaCMy;
250 BETA[3] = -betaCMz;
251 BETA[4] = gammaCM;
252
253 //The incident particle...
254
255 PA[1] = px;
256 PA[2] = py;
257 PA[3] = pz;
258 PA[4] = std::sqrt(M1*M1 + p*p);
259
260 G4double BETPA = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
261 G4double BPGAM = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
262
263 PB[1] = PA[1] + BPGAM * BETA[1];
264 PB[2] = PA[2] + BPGAM * BETA[2];
265 PB[3] = PA[3] + BPGAM * BETA[3];
266 PB[4] = (PA[4] - BETPA) * BETA[4];
267
268 G4DynamicParticle* newP = new G4DynamicParticle;
269 newP->SetDefinition(aParticle->GetDefinition());
270 newP->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
271
272 //The target particle...
273
274 PA[1] = -px;
275 PA[2] = -py;
276 PA[3] = -pz;
277 PA[4] = std::sqrt(M2*M2 + p*p);
278
279 BETPA = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
280 BPGAM = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
281
282 PB[1] = PA[1] + BPGAM * BETA[1];
283 PB[2] = PA[2] + BPGAM * BETA[2];
284 PB[3] = PA[3] + BPGAM * BETA[3];
285 PB[4] = (PA[4] - BETPA) * BETA[4];
286
287 targetParticle->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
288
289 if (verboseLevel > 1) {
290 G4cout << " particle 1 momentum in LAB "
291 << newP->GetMomentum()*(1./GeV)
292 << " " << newP->GetTotalMomentum()/GeV << G4endl;
293 G4cout << " particle 2 momentum in LAB "
294 << targetParticle->GetMomentum()*(1./GeV)
295 << " " << targetParticle->GetTotalMomentum()/GeV << G4endl;
296 G4cout << " TOTAL momentum in LAB "
297 << (newP->GetMomentum()+targetParticle->GetMomentum())*(1./GeV)
298 << " "
299 << (newP->GetMomentum()+targetParticle->GetMomentum()).mag()/GeV
300 << G4endl;
301 }
302
303 theParticleChange.SetMomentumChange(newP->GetMomentumDirection());
304 theParticleChange.SetEnergyChange(newP->GetKineticEnergy());
305 delete newP;
306 theParticleChange.AddSecondary(targetParticle, secID);
307
308 return &theParticleChange;
309 }
310
311 ////////////////////////////////////////////////////////////////////
312 //
313 // sample momentum transfer using Lab. momentum
314
315 G4double G4LEnp::SampleInvariantT(const G4ParticleDefinition* p,
316 G4double plab, G4int , G4int )
317 {
318 G4double nMass = p->GetPDGMass(); // 939.565346*MeV;
319 G4double ek = std::sqrt(plab*plab+nMass*nMass) - nMass;
320
321 // Find energy bin
322
323 G4int je1 = 0;
324 G4int je2 = NENERGY - 1;
325 ek = ek/GeV;
326
327 do
328 {
329 G4int midBin = (je1 + je2)/2;
330 if (ek < elab[midBin])
331 je2 = midBin;
332 else
333 je1 = midBin;
334 } while (je2 - je1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
335
336 G4double delab = elab[je2] - elab[je1];
337
338 // Sample the angle
339
340 G4double sample = G4UniformRand();
341 G4int ke1 = 0;
342 G4int ke2 = NANGLE - 1;
343 G4double dsig = sig[je2][0] - sig[je1][0];
344 G4double rc = dsig/delab;
345 G4double b = sig[je1][0] - rc*elab[je1];
346 G4double sigint1 = rc*ek + b;
347 G4double sigint2 = 0.;
348
349 do
350 {
351 G4int midBin = (ke1 + ke2)/2;
352 dsig = sig[je2][midBin] - sig[je1][midBin];
353 rc = dsig/delab;
354 b = sig[je1][midBin] - rc*elab[je1];
355 G4double sigint = rc*ek + b;
356
357 if (sample < sigint)
358 {
359 ke2 = midBin;
360 sigint2 = sigint;
361 }
362 else
363 {
364 ke1 = midBin;
365 sigint1 = sigint;
366 }
367 } while (ke2 - ke1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
368
369 dsig = sigint2 - sigint1;
370 rc = 1./dsig;
371 b = ke1 - rc*sigint1;
372
373 G4double kint = rc*sample + b;
374 G4double theta = (0.5 + kint)*pi/180.;
375 G4double t = 0.5*plab*plab*(1-std::cos(theta));
376
377 return t;
378 }
379
380 // end of file
381