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>> 26 // $Id: G4KleinNishinaCompton.cc 93362 2015-10-19 13:45:19Z gcosmo $
26 // 27 //
27 // ------------------------------------------- 28 // -------------------------------------------------------------------
28 // 29 //
29 // GEANT4 Class file 30 // GEANT4 Class file
30 // 31 //
31 // 32 //
32 // File name: G4KleinNishinaCompton 33 // File name: G4KleinNishinaCompton
33 // 34 //
34 // Author: Vladimir Ivanchenko on base 35 // Author: Vladimir Ivanchenko on base of Michel Maire code
35 // 36 //
36 // Creation date: 15.03.2005 37 // Creation date: 15.03.2005
37 // 38 //
38 // Modifications: 39 // Modifications:
39 // 18-04-05 Use G4ParticleChangeForGamma (V.Iv 40 // 18-04-05 Use G4ParticleChangeForGamma (V.Ivantchenko)
40 // 27-03-06 Remove upper limit of cross sectio 41 // 27-03-06 Remove upper limit of cross section (V.Ivantchenko)
41 // 42 //
42 // Class Description: 43 // Class Description:
43 // 44 //
44 // ------------------------------------------- 45 // -------------------------------------------------------------------
45 // 46 //
46 //....oooOO0OOooo........oooOO0OOooo........oo 47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
47 //....oooOO0OOooo........oooOO0OOooo........oo 48 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
48 49
49 #include "G4KleinNishinaCompton.hh" 50 #include "G4KleinNishinaCompton.hh"
50 #include "G4PhysicalConstants.hh" 51 #include "G4PhysicalConstants.hh"
51 #include "G4SystemOfUnits.hh" 52 #include "G4SystemOfUnits.hh"
52 #include "G4Electron.hh" 53 #include "G4Electron.hh"
53 #include "G4Gamma.hh" 54 #include "G4Gamma.hh"
54 #include "Randomize.hh" 55 #include "Randomize.hh"
55 #include "G4DataVector.hh" 56 #include "G4DataVector.hh"
56 #include "G4ParticleChangeForGamma.hh" 57 #include "G4ParticleChangeForGamma.hh"
57 #include "G4Log.hh" 58 #include "G4Log.hh"
58 #include "G4Exp.hh" 59 #include "G4Exp.hh"
59 60
60 //....oooOO0OOooo........oooOO0OOooo........oo 61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
61 62
62 using namespace std; 63 using namespace std;
63 64
>> 65 static const G4double
>> 66 d1= 2.7965e-1*CLHEP::barn, d2=-1.8300e-1*CLHEP::barn,
>> 67 d3= 6.7527 *CLHEP::barn, d4=-1.9798e+1*CLHEP::barn,
>> 68 e1= 1.9756e-5*CLHEP::barn, e2=-1.0205e-2*CLHEP::barn,
>> 69 e3=-7.3913e-2*CLHEP::barn, e4= 2.7079e-2*CLHEP::barn,
>> 70 f1=-3.9178e-7*CLHEP::barn, f2= 6.8241e-5*CLHEP::barn,
>> 71 f3= 6.0480e-5*CLHEP::barn, f4= 3.0274e-4*CLHEP::barn;
>> 72 static const G4int nlooplim = 1000;
>> 73
64 G4KleinNishinaCompton::G4KleinNishinaCompton(c 74 G4KleinNishinaCompton::G4KleinNishinaCompton(const G4ParticleDefinition*,
65 c 75 const G4String& nam)
66 : G4VEmModel(nam) 76 : G4VEmModel(nam)
67 { 77 {
68 theGamma = G4Gamma::Gamma(); 78 theGamma = G4Gamma::Gamma();
69 theElectron = G4Electron::Electron(); 79 theElectron = G4Electron::Electron();
70 lowestSecondaryEnergy = 100.0*eV; 80 lowestSecondaryEnergy = 100.0*eV;
71 fParticleChange = nullptr; 81 fParticleChange = nullptr;
72 } 82 }
73 83
74 //....oooOO0OOooo........oooOO0OOooo........oo 84 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
75 85
76 G4KleinNishinaCompton::~G4KleinNishinaCompton( << 86 G4KleinNishinaCompton::~G4KleinNishinaCompton()
>> 87 {}
77 88
78 //....oooOO0OOooo........oooOO0OOooo........oo 89 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
79 90
80 void G4KleinNishinaCompton::Initialise(const G 91 void G4KleinNishinaCompton::Initialise(const G4ParticleDefinition* p,
81 const G 92 const G4DataVector& cuts)
82 { 93 {
83 if(IsMaster()) { InitialiseElementSelectors( 94 if(IsMaster()) { InitialiseElementSelectors(p, cuts); }
84 if(nullptr == fParticleChange) { 95 if(nullptr == fParticleChange) {
85 fParticleChange = GetParticleChangeForGamm 96 fParticleChange = GetParticleChangeForGamma();
86 } 97 }
87 } 98 }
88 99
89 //....oooOO0OOooo........oooOO0OOooo........oo 100 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
90 101
91 void G4KleinNishinaCompton::InitialiseLocal(co 102 void G4KleinNishinaCompton::InitialiseLocal(const G4ParticleDefinition*,
92 G4 103 G4VEmModel* masterModel)
93 { 104 {
94 SetElementSelectors(masterModel->GetElementS 105 SetElementSelectors(masterModel->GetElementSelectors());
95 } 106 }
96 107
97 //....oooOO0OOooo........oooOO0OOooo........oo 108 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98 109
99 G4double G4KleinNishinaCompton::ComputeCrossSe 110 G4double G4KleinNishinaCompton::ComputeCrossSectionPerAtom(
100 const G 111 const G4ParticleDefinition*,
101 G 112 G4double GammaEnergy,
102 G 113 G4double Z, G4double,
103 G 114 G4double, G4double)
104 { 115 {
105 G4double xSection = 0.0 ; 116 G4double xSection = 0.0 ;
106 if (GammaEnergy <= LowEnergyLimit()) { retur 117 if (GammaEnergy <= LowEnergyLimit()) { return xSection; }
107 118
108 static const G4double a = 20.0 , b = 230.0 , 119 static const G4double a = 20.0 , b = 230.0 , c = 440.0;
109 <<
110 static const G4double <<
111 d1= 2.7965e-1*CLHEP::barn, d2=-1.8300e-1*CLH <<
112 d3= 6.7527 *CLHEP::barn, d4=-1.9798e+1*CLH <<
113 e1= 1.9756e-5*CLHEP::barn, e2=-1.0205e-2*CLH <<
114 e3=-7.3913e-2*CLHEP::barn, e4= 2.7079e-2*CLH <<
115 f1=-3.9178e-7*CLHEP::barn, f2= 6.8241e-5*CLH <<
116 f3= 6.0480e-5*CLHEP::barn, f4= 3.0274e-4*CLH <<
117 120
118 G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = 121 G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = Z*(d2 + e2*Z + f2*Z*Z),
119 p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = 122 p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = Z*(d4 + e4*Z + f4*Z*Z);
120 123
121 G4double T0 = 15.0*keV; 124 G4double T0 = 15.0*keV;
122 if (Z < 1.5) { T0 = 40.0*keV; } 125 if (Z < 1.5) { T0 = 40.0*keV; }
123 126
124 G4double X = max(GammaEnergy, T0) / electr 127 G4double X = max(GammaEnergy, T0) / electron_mass_c2;
125 xSection = p1Z*G4Log(1.+2.*X)/X 128 xSection = p1Z*G4Log(1.+2.*X)/X
126 + (p2Z + p3Z*X + p4Z*X*X)/(1. + 129 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
127 130
128 // modification for low energy. (special ca 131 // modification for low energy. (special case for Hydrogen)
129 if (GammaEnergy < T0) { 132 if (GammaEnergy < T0) {
130 static const G4double dT0 = keV; 133 static const G4double dT0 = keV;
131 X = (T0+dT0) / electron_mass_c2 ; 134 X = (T0+dT0) / electron_mass_c2 ;
132 G4double sigma = p1Z*G4Log(1.+2*X)/X 135 G4double sigma = p1Z*G4Log(1.+2*X)/X
133 + (p2Z + p3Z*X + p4Z*X*X)/ 136 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
134 G4double c1 = -T0*(sigma-xSection)/(xSec 137 G4double c1 = -T0*(sigma-xSection)/(xSection*dT0);
135 G4double c2 = 0.150; 138 G4double c2 = 0.150;
136 if (Z > 1.5) { c2 = 0.375-0.0556*G4Log(Z); 139 if (Z > 1.5) { c2 = 0.375-0.0556*G4Log(Z); }
137 G4double y = G4Log(GammaEnergy/T0); 140 G4double y = G4Log(GammaEnergy/T0);
138 xSection *= G4Exp(-y*(c1+c2*y)); 141 xSection *= G4Exp(-y*(c1+c2*y));
139 } 142 }
140 // G4cout<<"e= "<< GammaEnergy<<" Z= "<<Z<<" 143 // G4cout<<"e= "<< GammaEnergy<<" Z= "<<Z<<" cross= " << xSection << G4endl;
141 return xSection; 144 return xSection;
142 } 145 }
143 146
144 //....oooOO0OOooo........oooOO0OOooo........oo 147 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
145 148
146 void G4KleinNishinaCompton::SampleSecondaries( 149 void G4KleinNishinaCompton::SampleSecondaries(
147 std::vector<G4Dyna 150 std::vector<G4DynamicParticle*>* fvect,
148 const G4MaterialCu 151 const G4MaterialCutsCouple*,
149 const G4DynamicPar 152 const G4DynamicParticle* aDynamicGamma,
150 G4double, 153 G4double,
151 G4double) 154 G4double)
152 { 155 {
153 // The scattered gamma energy is sampled acc 156 // The scattered gamma energy is sampled according to Klein - Nishina formula.
154 // The random number techniques of Butcher & 157 // The random number techniques of Butcher & Messel are used
155 // (Nuc Phys 20(1960),15). 158 // (Nuc Phys 20(1960),15).
156 // Note : Effects due to binding of atomic e 159 // Note : Effects due to binding of atomic electrons are negliged.
157 160
158 G4double gamEnergy0 = aDynamicGamma->GetKine 161 G4double gamEnergy0 = aDynamicGamma->GetKineticEnergy();
159 162
160 // do nothing below the threshold 163 // do nothing below the threshold
161 if(gamEnergy0 <= LowEnergyLimit()) { return; 164 if(gamEnergy0 <= LowEnergyLimit()) { return; }
162 165
163 G4double E0_m = gamEnergy0 / electron_mass_c 166 G4double E0_m = gamEnergy0 / electron_mass_c2 ;
164 167
165 G4ThreeVector gamDirection0 = aDynamicGamma- 168 G4ThreeVector gamDirection0 = aDynamicGamma->GetMomentumDirection();
166 169
167 // 170 //
168 // sample the energy rate of the scattered g 171 // sample the energy rate of the scattered gamma
169 // 172 //
170 173
171 G4double epsilon, epsilonsq, onecost, sint2, 174 G4double epsilon, epsilonsq, onecost, sint2, greject ;
172 175
173 G4double eps0 = 1./(1. + 2.*E0_m); 176 G4double eps0 = 1./(1. + 2.*E0_m);
174 G4double epsilon0sq = eps0*eps0; 177 G4double epsilon0sq = eps0*eps0;
175 G4double alpha1 = - G4Log(eps0); 178 G4double alpha1 = - G4Log(eps0);
176 G4double alpha2 = alpha1 + 0.5*(1.- epsi 179 G4double alpha2 = alpha1 + 0.5*(1.- epsilon0sq);
177 180
178 CLHEP::HepRandomEngine* rndmEngineMod = G4Ra 181 CLHEP::HepRandomEngine* rndmEngineMod = G4Random::getTheEngine();
179 G4double rndm[3]; 182 G4double rndm[3];
180 183
181 static const G4int nlooplim = 1000; <<
182 G4int nloop = 0; 184 G4int nloop = 0;
183 do { 185 do {
184 ++nloop; 186 ++nloop;
185 // false interaction if too many iteration 187 // false interaction if too many iterations
186 if(nloop > nlooplim) { return; } 188 if(nloop > nlooplim) { return; }
187 189
188 // 3 random numbers to sample scattering 190 // 3 random numbers to sample scattering
189 rndmEngineMod->flatArray(3, rndm); 191 rndmEngineMod->flatArray(3, rndm);
190 192
191 if ( alpha1 > alpha2*rndm[0] ) { 193 if ( alpha1 > alpha2*rndm[0] ) {
192 epsilon = G4Exp(-alpha1*rndm[1]); // 194 epsilon = G4Exp(-alpha1*rndm[1]); // eps0**r
193 epsilonsq = epsilon*epsilon; 195 epsilonsq = epsilon*epsilon;
194 196
195 } else { 197 } else {
196 epsilonsq = epsilon0sq + (1.- epsilon0sq 198 epsilonsq = epsilon0sq + (1.- epsilon0sq)*rndm[1];
197 epsilon = sqrt(epsilonsq); 199 epsilon = sqrt(epsilonsq);
198 }; 200 };
199 201
200 onecost = (1.- epsilon)/(epsilon*E0_m); 202 onecost = (1.- epsilon)/(epsilon*E0_m);
201 sint2 = onecost*(2.-onecost); 203 sint2 = onecost*(2.-onecost);
202 greject = 1. - epsilon*sint2/(1.+ epsilons 204 greject = 1. - epsilon*sint2/(1.+ epsilonsq);
203 205
204 // Loop checking, 03-Aug-2015, Vladimir Iv 206 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
205 } while (greject < rndm[2]); 207 } while (greject < rndm[2]);
206 208
207 // 209 //
208 // scattered gamma angles. ( Z - axis along 210 // scattered gamma angles. ( Z - axis along the parent gamma)
209 // 211 //
210 212
211 if(sint2 < 0.0) { sint2 = 0.0; } 213 if(sint2 < 0.0) { sint2 = 0.0; }
212 G4double cosTeta = 1. - onecost; 214 G4double cosTeta = 1. - onecost;
213 G4double sinTeta = sqrt (sint2); 215 G4double sinTeta = sqrt (sint2);
214 G4double Phi = twopi * rndmEngineMod->fl 216 G4double Phi = twopi * rndmEngineMod->flat();
215 217
216 // 218 //
217 // update G4VParticleChange for the scattere 219 // update G4VParticleChange for the scattered gamma
218 // 220 //
219 221
220 G4ThreeVector gamDirection1(sinTeta*cos(Phi) 222 G4ThreeVector gamDirection1(sinTeta*cos(Phi), sinTeta*sin(Phi), cosTeta);
221 gamDirection1.rotateUz(gamDirection0); 223 gamDirection1.rotateUz(gamDirection0);
222 G4double gamEnergy1 = epsilon*gamEnergy0; 224 G4double gamEnergy1 = epsilon*gamEnergy0;
223 G4double edep = 0.0; 225 G4double edep = 0.0;
224 if(gamEnergy1 > lowestSecondaryEnergy) { 226 if(gamEnergy1 > lowestSecondaryEnergy) {
225 fParticleChange->ProposeMomentumDirection( 227 fParticleChange->ProposeMomentumDirection(gamDirection1);
226 fParticleChange->SetProposedKineticEnergy( 228 fParticleChange->SetProposedKineticEnergy(gamEnergy1);
227 } else { 229 } else {
228 fParticleChange->ProposeTrackStatus(fStopA 230 fParticleChange->ProposeTrackStatus(fStopAndKill);
229 fParticleChange->SetProposedKineticEnergy( 231 fParticleChange->SetProposedKineticEnergy(0.0);
230 edep = gamEnergy1; 232 edep = gamEnergy1;
231 } 233 }
232 234
233 // 235 //
234 // kinematic of the scattered electron 236 // kinematic of the scattered electron
235 // 237 //
236 238
237 G4double eKinEnergy = gamEnergy0 - gamEnergy 239 G4double eKinEnergy = gamEnergy0 - gamEnergy1;
238 240
239 if(eKinEnergy > lowestSecondaryEnergy) { 241 if(eKinEnergy > lowestSecondaryEnergy) {
240 G4ThreeVector eDirection = gamEnergy0*gamD 242 G4ThreeVector eDirection = gamEnergy0*gamDirection0 - gamEnergy1*gamDirection1;
241 eDirection = eDirection.unit(); 243 eDirection = eDirection.unit();
242 244
243 // create G4DynamicParticle object for the 245 // create G4DynamicParticle object for the electron.
244 auto dp = new G4DynamicParticle(theElectro << 246 G4DynamicParticle* dp = new G4DynamicParticle(theElectron,eDirection,eKinEnergy);
245 fvect->push_back(dp); 247 fvect->push_back(dp);
246 } else { 248 } else {
247 edep += eKinEnergy; 249 edep += eKinEnergy;
248 } 250 }
249 // energy balance 251 // energy balance
250 if(edep > 0.0) { 252 if(edep > 0.0) {
251 fParticleChange->ProposeLocalEnergyDeposit 253 fParticleChange->ProposeLocalEnergyDeposit(edep);
252 } 254 }
253 } 255 }
254 256
255 //....oooOO0OOooo........oooOO0OOooo........oo 257 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
256 258
257 259
258 260