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25 // 25 //
26 // INCL++ intra-nuclear cascade model 26 // INCL++ intra-nuclear cascade model
27 // Alain Boudard, CEA-Saclay, France 27 // Alain Boudard, CEA-Saclay, France
28 // Joseph Cugnon, University of Liege, Belgium 28 // Joseph Cugnon, University of Liege, Belgium
29 // Jean-Christophe David, CEA-Saclay, France 29 // Jean-Christophe David, CEA-Saclay, France
30 // Pekka Kaitaniemi, CEA-Saclay, France, and H 30 // Pekka Kaitaniemi, CEA-Saclay, France, and Helsinki Institute of Physics, Finland
31 // Sylvie Leray, CEA-Saclay, France 31 // Sylvie Leray, CEA-Saclay, France
32 // Davide Mancusi, CEA-Saclay, France 32 // Davide Mancusi, CEA-Saclay, France
33 // 33 //
34 #define INCLXX_IN_GEANT4_MODE 1 34 #define INCLXX_IN_GEANT4_MODE 1
35 35
36 #include "globals.hh" 36 #include "globals.hh"
37 37
38 #include "G4INCLElasticChannel.hh" 38 #include "G4INCLElasticChannel.hh"
39 #include "G4INCLRandom.hh" 39 #include "G4INCLRandom.hh"
40 #include "G4INCLKinematicsUtils.hh" 40 #include "G4INCLKinematicsUtils.hh"
41 #include "G4INCLParticleTable.hh" 41 #include "G4INCLParticleTable.hh"
42 #include "G4INCLCrossSections.hh" 42 #include "G4INCLCrossSections.hh"
43 #include "G4INCLGlobals.hh" 43 #include "G4INCLGlobals.hh"
44 44
45 namespace G4INCL { 45 namespace G4INCL {
46 46
47 ElasticChannel::ElasticChannel(Particle *p1, 47 ElasticChannel::ElasticChannel(Particle *p1, Particle *p2)
48 :particle1(p1), particle2(p2) 48 :particle1(p1), particle2(p2)
49 { 49 {
50 } 50 }
51 51
52 ElasticChannel::~ElasticChannel() 52 ElasticChannel::~ElasticChannel()
53 { 53 {
54 } 54 }
55 55
56 void ElasticChannel::fillFinalState(FinalSta 56 void ElasticChannel::fillFinalState(FinalState *fs)
57 { 57 {
58 ParticleType p1TypeOld = particle1->getTyp 58 ParticleType p1TypeOld = particle1->getType();
59 ParticleType p2TypeOld = particle2->getTyp 59 ParticleType p2TypeOld = particle2->getType();
60 60
61 /* Concerning the way we calculate the lab 61 /* Concerning the way we calculate the lab momentum, see the considerations
62 * in CrossSections::elasticNNLegacy(). 62 * in CrossSections::elasticNNLegacy().
63 */ 63 */
64 const G4double s = KinematicsUtils::square 64 const G4double s = KinematicsUtils::squareTotalEnergyInCM(particle1, particle2);
65 const G4double pl = KinematicsUtils::momen 65 const G4double pl = KinematicsUtils::momentumInLab(s, ParticleTable::effectiveNucleonMass, ParticleTable::effectiveNucleonMass);
66 66
67 const G4int isospin = ParticleTable::getIs 67 const G4int isospin = ParticleTable::getIsospin(particle1->getType()) +
68 ParticleTable::getIsospin(particle2->get 68 ParticleTable::getIsospin(particle2->getType());
69 69
70 // Calculate the outcome of the channel: 70 // Calculate the outcome of the channel:
71 G4double psq = particle1->getMomentum().ma 71 G4double psq = particle1->getMomentum().mag2();
72 G4double pnorm = std::sqrt(psq); 72 G4double pnorm = std::sqrt(psq);
73 G4double b = CrossSections::calculateNNAng 73 G4double b = CrossSections::calculateNNAngularSlope(pl, isospin);
74 G4double btmax = 4.0 * psq * b; 74 G4double btmax = 4.0 * psq * b;
75 G4double z = std::exp(-btmax); 75 G4double z = std::exp(-btmax);
76 G4double ranres = Random::shoot(); 76 G4double ranres = Random::shoot();
77 G4double y = 1.0 - ranres * (1.0 - z); 77 G4double y = 1.0 - ranres * (1.0 - z);
78 G4double T = std::log(y)/b; 78 G4double T = std::log(y)/b;
79 G4int iexpi = 0; 79 G4int iexpi = 0;
80 G4double apt = 1.0; 80 G4double apt = 1.0;
81 81
82 // Handle np case 82 // Handle np case
83 if((particle1->getType() == Proton && part 83 if((particle1->getType() == Proton && particle2->getType() == Neutron) ||
84 (particle1->getType() == Neutron && par 84 (particle1->getType() == Neutron && particle2->getType() == Proton)) {
85 if(pl > 800.0) { 85 if(pl > 800.0) {
86 const G4double x = 0.001 * pl; // Tran 86 const G4double x = 0.001 * pl; // Transform to GeV
87 apt = (800.0/pl)*(800.0/pl); 87 apt = (800.0/pl)*(800.0/pl);
88 G4double cpt = std::max(6.23 * std::ex 88 G4double cpt = std::max(6.23 * std::exp(-1.79*x), 0.3);
89 G4double alphac = 100.0 * 1.0e-6; 89 G4double alphac = 100.0 * 1.0e-6;
90 G4double aaa = (1 + apt) * (1 - std::e 90 G4double aaa = (1 + apt) * (1 - std::exp(-btmax))/b;
91 G4double argu = psq * alphac; 91 G4double argu = psq * alphac;
92 92
93 if(argu >= 8) { 93 if(argu >= 8) {
94 argu = 0.0; 94 argu = 0.0;
95 } else { 95 } else {
96 argu = std::exp(-4.0 * argu); 96 argu = std::exp(-4.0 * argu);
97 } 97 }
98 98
99 G4double aac = cpt * (1.0 - argu)/alph 99 G4double aac = cpt * (1.0 - argu)/alphac;
100 G4double fracpn = aaa/(aac + aaa); 100 G4double fracpn = aaa/(aac + aaa);
101 if(Random::shoot() > fracpn) { 101 if(Random::shoot() > fracpn) {
102 z = std::exp(-4.0 * psq *alphac); 102 z = std::exp(-4.0 * psq *alphac);
103 iexpi = 1; 103 iexpi = 1;
104 y = 1.0 - ranres*(1.0 - z); 104 y = 1.0 - ranres*(1.0 - z);
105 T = std::log(y)/alphac; 105 T = std::log(y)/alphac;
106 } 106 }
107 } 107 }
108 } 108 }
109 109
110 G4double ctet = 1.0 + 0.5*T/psq; 110 G4double ctet = 1.0 + 0.5*T/psq;
111 if(std::abs(ctet) > 1.0) ctet = Math::sign 111 if(std::abs(ctet) > 1.0) ctet = Math::sign(ctet);
112 G4double stet = std::sqrt(1.0 - ctet*ctet) 112 G4double stet = std::sqrt(1.0 - ctet*ctet);
113 G4double rndm = Random::shoot(); 113 G4double rndm = Random::shoot();
114 114
115 G4double fi = Math::twoPi * rndm; 115 G4double fi = Math::twoPi * rndm;
116 G4double cfi = std::cos(fi); 116 G4double cfi = std::cos(fi);
117 G4double sfi = std::sin(fi); 117 G4double sfi = std::sin(fi);
118 118
119 G4double xx = particle1->getMomentum().per 119 G4double xx = particle1->getMomentum().perp2();
120 G4double zz = std::pow(particle1->getMomen 120 G4double zz = std::pow(particle1->getMomentum().getZ(), 2);
121 121
122 if(xx >= (zz * 1.0e-8)) { 122 if(xx >= (zz * 1.0e-8)) {
123 ThreeVector p = particle1->getMomentum() 123 ThreeVector p = particle1->getMomentum();
124 G4double yn = std::sqrt(xx); 124 G4double yn = std::sqrt(xx);
125 G4double zn = yn * pnorm; 125 G4double zn = yn * pnorm;
126 G4double ex[3], ey[3], ez[3]; 126 G4double ex[3], ey[3], ez[3];
127 ez[0] = p.getX() / pnorm; 127 ez[0] = p.getX() / pnorm;
128 ez[1] = p.getY() / pnorm; 128 ez[1] = p.getY() / pnorm;
129 ez[2] = p.getZ() / pnorm; 129 ez[2] = p.getZ() / pnorm;
130 130
131 // Vector Ex is chosen arbitrarily: 131 // Vector Ex is chosen arbitrarily:
132 ex[0] = p.getY() / yn; 132 ex[0] = p.getY() / yn;
133 ex[1] = -p.getX() / yn; 133 ex[1] = -p.getX() / yn;
134 ex[2] = 0.0; 134 ex[2] = 0.0;
135 135
136 ey[0] = p.getX() * p.getZ() / zn; 136 ey[0] = p.getX() * p.getZ() / zn;
137 ey[1] = p.getY() * p.getZ() / zn; 137 ey[1] = p.getY() * p.getZ() / zn;
138 ey[2] = -xx/zn; 138 ey[2] = -xx/zn;
139 139
140 G4double pX = (ex[0]*cfi*stet + ey[0]*sf 140 G4double pX = (ex[0]*cfi*stet + ey[0]*sfi*stet + ez[0]*ctet) * pnorm;
141 G4double pY = (ex[1]*cfi*stet + ey[1]*sf 141 G4double pY = (ex[1]*cfi*stet + ey[1]*sfi*stet + ez[1]*ctet) * pnorm;
142 G4double pZ = (ex[2]*cfi*stet + ey[2]*sf 142 G4double pZ = (ex[2]*cfi*stet + ey[2]*sfi*stet + ez[2]*ctet) * pnorm;
143 143
144 ThreeVector p1momentum = ThreeVector(pX, 144 ThreeVector p1momentum = ThreeVector(pX, pY, pZ);
145 particle1->setMomentum(p1momentum); 145 particle1->setMomentum(p1momentum);
146 particle2->setMomentum(-p1momentum); 146 particle2->setMomentum(-p1momentum);
147 } else { // if(xx < (zz * 1.0e-8)) { 147 } else { // if(xx < (zz * 1.0e-8)) {
148 G4double momZ = particle1->getMomentum() 148 G4double momZ = particle1->getMomentum().getZ();
149 G4double pX = momZ * cfi * stet; 149 G4double pX = momZ * cfi * stet;
150 G4double pY = momZ * sfi * stet; 150 G4double pY = momZ * sfi * stet;
151 G4double pZ = momZ * ctet; 151 G4double pZ = momZ * ctet;
152 152
153 ThreeVector p1momentum(pX, pY, pZ); 153 ThreeVector p1momentum(pX, pY, pZ);
154 particle1->setMomentum(p1momentum); 154 particle1->setMomentum(p1momentum);
155 particle2->setMomentum(-p1momentum); 155 particle2->setMomentum(-p1momentum);
156 } 156 }
157 157
158 // Handle backward scattering here. 158 // Handle backward scattering here.
159 159
160 if((particle1->getType() == Proton && part 160 if((particle1->getType() == Proton && particle2->getType() == Neutron) ||
161 (particle1->getType() == Neutron && par 161 (particle1->getType() == Neutron && particle2->getType() == Proton)) {
162 rndm = Random::shoot(); 162 rndm = Random::shoot();
163 apt = 1.0; 163 apt = 1.0;
164 if(pl > 800.0) { 164 if(pl > 800.0) {
165 apt = std::pow(800.0/pl, 2); 165 apt = std::pow(800.0/pl, 2);
166 } 166 }
167 if(iexpi == 1 || rndm > 1.0/(1.0 + apt)) 167 if(iexpi == 1 || rndm > 1.0/(1.0 + apt)) {
168 particle1->setType(p2TypeOld); 168 particle1->setType(p2TypeOld);
169 particle2->setType(p1TypeOld); 169 particle2->setType(p1TypeOld);
170 } 170 }
171 } 171 }
172 172
173 // Note: there is no need to update the ki 173 // Note: there is no need to update the kinetic energies of the particles,
174 // as this is elastic scattering. 174 // as this is elastic scattering.
175 175
176 fs->addModifiedParticle(particle1); 176 fs->addModifiedParticle(particle1);
177 fs->addModifiedParticle(particle2); 177 fs->addModifiedParticle(particle2);
178 178
179 } 179 }
180 180
181 } 181 }
182 182