source: trunk/source/processes/hadronic/models/coherent_elastic/src/G4LEpp.cc @ 1196

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26
27 // G4 Low energy model: n-n or p-p scattering
28 // F.W. Jones, L.G. Greeniaus, H.P. Wellisch
29
30
31#include "G4LEpp.hh"
32#include "Randomize.hh"
33#include "G4ios.hh"
34
35// Initialization of static data arrays:
36#include "G4LEppData.hh"
37
38G4LEpp::G4LEpp():G4HadronicInteraction("G4LEpp")
39{
40  //    theParticleChange.SetNumberOfSecondaries(1);
41  //    SetMinEnergy(10.*MeV);
42  //    SetMaxEnergy(1200.*MeV);
43
44  SetCoulombEffects(0);
45
46  SetMinEnergy(0.);
47  SetMaxEnergy(1200.*GeV);
48}
49
50G4LEpp::~G4LEpp()
51{
52  //    theParticleChange.Clear();
53}
54
55
56void
57G4LEpp::SetCoulombEffects(G4int State)
58{
59  if (State) {
60    for(G4int i=0; i<NANGLE; i++)
61    {
62      sig[i] = SigCoul[i];
63    }
64    elab = ElabCoul;
65  }
66  else {
67    for(G4int i=0; i<NANGLE; i++)
68    {
69      sig[i] = Sig[i];
70    }
71    elab = Elab;
72  }
73}
74
75
76G4HadFinalState*
77G4LEpp::ApplyYourself(const G4HadProjectile& aTrack, G4Nucleus& targetNucleus)
78{
79    theParticleChange.Clear();
80    const G4HadProjectile* aParticle = &aTrack;
81
82    G4double P = aParticle->GetTotalMomentum();
83    G4double Px = aParticle->Get4Momentum().x();
84    G4double Py = aParticle->Get4Momentum().y();
85    G4double Pz = aParticle->Get4Momentum().z();
86    G4double ek = aParticle->GetKineticEnergy();
87    G4ThreeVector theInitial = aParticle->Get4Momentum().vect();
88
89//    if (verboseLevel > 1)
90         {
91      G4double E = aParticle->GetTotalEnergy();
92      G4double E0 = aParticle->GetDefinition()->GetPDGMass();
93      G4double Q = aParticle->GetDefinition()->GetPDGCharge();
94      G4double N = targetNucleus.GetN();
95      G4double Z = targetNucleus.GetZ();
96      G4cout << "G4LEpp:ApplyYourself: incident particle: "
97             << aParticle->GetDefinition()->GetParticleName() << G4endl;
98      G4cout << "P = " << P/GeV << " GeV/c"
99             << ", Px = " << Px/GeV << " GeV/c"
100             << ", Py = " << Py/GeV << " GeV/c"
101             << ", Pz = " << Pz/GeV << " GeV/c" << G4endl;
102      G4cout << "E = " << E/GeV << " GeV"
103             << ", kinetic energy = " << ek/GeV << " GeV"
104             << ", mass = " << E0/GeV << " GeV"
105             << ", charge = " << Q << G4endl;
106      G4cout << "G4LEpp:ApplyYourself: material:" << G4endl;
107      G4cout << "A = " << N
108             << ", Z = " << Z
109             << ", atomic mass " 
110             <<  G4Proton::Proton()->GetPDGMass()/GeV << "GeV" 
111             << G4endl;
112      //
113      // GHEISHA ADD operation to get total energy, mass, charge
114      //
115      E += G4Proton::Proton()->GetPDGMass();
116      G4double E02 = E*E - P*P;
117      E0 = std::sqrt(std::abs(E02));
118      if (E02 < 0)E0 *= -1;
119      Q += Z;
120      G4cout << "G4LEpp:ApplyYourself: total:" << G4endl;
121      G4cout << "E = " << E/GeV << " GeV"
122             << ", mass = " << E0/GeV << " GeV"
123             << ", charge = " << Q << G4endl;
124    }
125
126    // Find energy bin
127
128    G4int je1 = 0;
129    G4int je2 = NENERGY - 1;
130    ek = ek/GeV;
131    do {
132      G4int midBin = (je1 + je2)/2;
133      if (ek < elab[midBin])
134        je2 = midBin;
135      else
136        je1 = midBin;
137    } while (je2 - je1 > 1); 
138    //    G4int j;
139    //std::abs(ek-elab[je1]) < std::abs(ek-elab[je2]) ? j = je1 : j = je2;
140    G4double delab = elab[je2] - elab[je1];
141
142    // Sample the angle
143
144    G4float sample = G4UniformRand();
145    G4int ke1 = 0;
146    G4int ke2 = NANGLE - 1;
147    G4double dsig = sig[je2][0] - sig[je1][0];
148    G4double rc = dsig/delab;
149    G4double b = sig[je1][0] - rc*elab[je1];
150    G4double sigint1 = rc*ek + b;
151    G4double sigint2 = 0.;
152
153    if (verboseLevel > 1) G4cout << "sample=" << sample << G4endl
154                                 << ke1 << " " << ke2 << " " 
155                                 << sigint1 << " " << sigint2 << G4endl;
156
157    do {
158      G4int midBin = (ke1 + ke2)/2;
159      dsig = sig[je2][midBin] - sig[je1][midBin];
160      rc = dsig/delab;
161      b = sig[je1][midBin] - rc*elab[je1];
162      G4double sigint = rc*ek + b;
163      if (sample < sigint) {
164        ke2 = midBin;
165        sigint2 = sigint;
166      }
167      else {
168        ke1 = midBin;
169        sigint1 = sigint;
170      }
171      if (verboseLevel > 1)G4cout << ke1 << " " << ke2 << " " 
172                                  << sigint1 << " " << sigint2 << G4endl;
173    } while (ke2 - ke1 > 1); 
174
175    // sigint1 and sigint2 should be recoverable from above loop
176
177    //    G4double dsig = sig[je2][ke1] - sig[je1][ke1];
178    //    G4double rc = dsig/delab;
179    //    G4double b = sig[je1][ke1] - rc*elab[je1];
180    //    G4double sigint1 = rc*ek + b;
181
182    //    G4double dsig = sig[je2][ke2] - sig[je1][ke2];
183    //    G4double rc = dsig/delab;
184    //    G4double b = sig[je1][ke2] - rc*elab[je1];
185    //    G4double sigint2 = rc*ek + b;
186
187    dsig = sigint2 - sigint1;
188    rc = 1./dsig;
189    b = ke1 - rc*sigint1;
190    G4double kint = rc*sample + b;
191    G4double theta = (0.5 + kint)*pi/180.;
192    if (theta < 0.) theta = 0.;
193
194    //    G4int k;
195    //std::abs(sample-sig[j][ke1]) < std::abs(sample-sig[j][ke2]) ? k = ke1 : k = ke2;
196    //    G4double theta = (0.5 + k)*pi/180.;
197
198    if (verboseLevel > 1) {
199      G4cout << "   energy bin " << je1 << " energy=" << elab[je1] << G4endl;
200      G4cout << "   angle bin " << kint << " angle=" << theta/degree << G4endl;
201    }
202
203
204    // Get the target particle
205
206    G4DynamicParticle* targetParticle = targetNucleus.ReturnTargetParticle();
207
208    G4double E1 = aParticle->GetTotalEnergy();
209    G4double M1 = aParticle->GetDefinition()->GetPDGMass();
210    G4double E2 = targetParticle->GetTotalEnergy();
211    G4double M2 = targetParticle->GetDefinition()->GetPDGMass();
212    G4double totalEnergy = E1 + E2;
213    G4double pseudoMass = std::sqrt(totalEnergy*totalEnergy - P*P);
214    // pseudoMass also = std::sqrt(M1*M1 + M2*M2 + 2*M2*E1)
215
216    // Transform into centre of mass system
217
218    G4double px = (M2/pseudoMass)*Px;
219    G4double py = (M2/pseudoMass)*Py;
220    G4double pz = (M2/pseudoMass)*Pz;
221    G4double p = std::sqrt(px*px + py*py + pz*pz);
222
223    if (verboseLevel > 1) {
224      G4cout << "  E1, M1 (GeV) " << E1/GeV << " " << M1/GeV << G4endl;
225      G4cout << "  E2, M2 (GeV) " << E2/GeV << " " << M2/GeV << G4endl;
226      G4cout << "  particle  1 momentum in CM " << px/GeV << " " << py/GeV << " "
227           << pz/GeV << " " << p/GeV << G4endl;
228    }
229
230    // First scatter w.r.t. Z axis
231    G4double phi = G4UniformRand()*twopi;
232    G4double pxnew = p*std::sin(theta)*std::cos(phi);
233    G4double pynew = p*std::sin(theta)*std::sin(phi);
234    G4double pznew = p*std::cos(theta);
235
236    // Rotate according to the direction of the incident particle
237    if (px*px + py*py > 0) {
238      G4double cost, sint, ph, cosp, sinp;
239      cost = pz/p;
240      sint = (std::sqrt(std::abs((1-cost)*(1+cost))) + std::sqrt(px*px+py*py)/p)/2;
241      py < 0 ? ph = 3*halfpi : ph = halfpi;
242      if (std::abs(px) > 0.000001*GeV) ph = std::atan2(py,px);
243      cosp = std::cos(ph);
244      sinp = std::sin(ph);
245      px = (cost*cosp*pxnew - sinp*pynew + sint*cosp*pznew);
246      py = (cost*sinp*pxnew + cosp*pynew + sint*sinp*pznew);
247      pz = (-sint*pxnew                  + cost*pznew);
248      //      G4ThreeVector it(a,b,c);
249      //      p0->SetMomentum(it);
250      //      G4ThreeVector aTargetMom = theInitial - it;
251      //      targetParticle->SetMomentum(aTargetMom);
252    }
253    else {
254      px = pxnew;
255      py = pynew;
256      pz = pznew;
257    }
258
259    if (verboseLevel > 1) {
260      G4cout << "  AFTER SCATTER..." << G4endl;
261      G4cout << "  particle 1 momentum in CM " << px/GeV << " " << py/GeV << " "
262           << pz/GeV << " " << p/GeV << G4endl;
263    }
264
265    // Transform to lab system
266
267    G4double E1pM2 = E1 + M2;
268    G4double betaCM  = P/E1pM2;
269    G4double betaCMx = Px/E1pM2;
270    G4double betaCMy = Py/E1pM2;
271    G4double betaCMz = Pz/E1pM2;
272    G4double gammaCM = E1pM2/std::sqrt(E1pM2*E1pM2 - P*P);
273
274    if (verboseLevel > 1) {
275      G4cout << "  betaCM " << betaCMx << " " << betaCMy << " "
276             << betaCMz << " " << betaCM << G4endl;
277      G4cout << "  gammaCM " << gammaCM << G4endl;
278    }
279
280    // Now following GLOREN...
281
282    G4double BETA[5], PA[5], PB[5];
283    BETA[1] = -betaCMx;
284    BETA[2] = -betaCMy;
285    BETA[3] = -betaCMz;
286    BETA[4] = gammaCM;
287
288    //The incident particle...
289
290    PA[1] = px;
291    PA[2] = py;
292    PA[3] = pz;
293    PA[4] = std::sqrt(M1*M1 + p*p);
294
295    G4double BETPA  = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
296    G4double BPGAM  = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
297
298    PB[1] = PA[1] + BPGAM  * BETA[1];
299    PB[2] = PA[2] + BPGAM  * BETA[2];
300    PB[3] = PA[3] + BPGAM  * BETA[3];
301    PB[4] = (PA[4] - BETPA) * BETA[4];
302
303    G4DynamicParticle* newP = new G4DynamicParticle;
304    newP->SetDefinition(const_cast<G4ParticleDefinition *>(aParticle->GetDefinition()) );
305    newP->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
306
307
308    //The target particle...
309
310    PA[1] = -px;
311    PA[2] = -py;
312    PA[3] = -pz;
313    PA[4] = std::sqrt(M2*M2 + p*p);
314
315    BETPA  = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
316    BPGAM  = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
317
318    PB[1] = PA[1] + BPGAM  * BETA[1];
319    PB[2] = PA[2] + BPGAM  * BETA[2];
320    PB[3] = PA[3] + BPGAM  * BETA[3];
321    PB[4] = (PA[4] - BETPA) * BETA[4];
322
323    targetParticle->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
324
325    // G4double ektotal = newP->GetKineticEnergy() +
326    //                    targetParticle->GetKineticEnergy();
327
328    if (verboseLevel > 1) {
329      G4cout << "  particle 1 momentum in LAB " 
330           << newP->GetMomentum()*(1./GeV) 
331           << " " << newP->GetTotalMomentum()/GeV << G4endl;
332      G4cout << "  particle 2 momentum in LAB " 
333           << targetParticle->GetMomentum()*(1./GeV) 
334           << " " << targetParticle->GetTotalMomentum()/GeV << G4endl;
335      G4cout << "  TOTAL momentum in LAB " 
336           << (newP->GetMomentum()+targetParticle->GetMomentum())*(1./GeV) 
337           << " " 
338           << (newP->GetMomentum()+targetParticle->GetMomentum()).mag()/GeV
339           << G4endl;
340    }
341
342    //    if (theta < pi/2.) {
343      //  G4double p = newP->GetMomentum().mag();
344      //      G4ThreeVector m = newP->GetMomentum();
345      //      if (p > DBL_MIN)
346      //        theParticleChange.SetMomentumChange(m.x()/p, m.y()/p, m.z()/p);
347      //      else
348      //        theParticleChange.SetMomentumChange(0., 0., 0.);
349
350      theParticleChange.SetMomentumChange( newP->GetMomentumDirection());
351      theParticleChange.SetEnergyChange(newP->GetKineticEnergy());
352      delete newP;
353
354      //    }
355      //    else {
356      //      // charge exchange
357      //      theParticleChange.SetNumberOfSecondaries(2);
358      //      theParticleChange.AddSecondary(newP);
359      //      theParticleChange.SetStatusChange(fStopAndKill);
360      //      //      theParticleChange.SetEnergyChange(0.0);
361      //    }
362
363    // Recoil particle
364    G4DynamicParticle* p1 = new G4DynamicParticle;
365    p1->SetDefinition(targetParticle->GetDefinition());
366    p1->SetMomentum(targetParticle->GetMomentum());
367    theParticleChange.AddSecondary(p1);   
368   
369
370    return &theParticleChange;
371}
372
373 // end of file
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