| Geant4 Cross Reference |
1 // 1 //
2 // ******************************************* 2 // ********************************************************************
3 // * License and Disclaimer 3 // * License and Disclaimer *
4 // * 4 // * *
5 // * The Geant4 software is copyright of th 5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided 6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License 7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/ 8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. 9 // * include a list of copyright holders. *
10 // * 10 // * *
11 // * Neither the authors of this software syst 11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing fin 12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warran 13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assum 14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file 15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. *
17 // * 17 // * *
18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distri 20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you ag 21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publicati 22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Sof 23 // * acceptance of all terms of the Geant4 Software license. *
24 // ******************************************* 24 // ********************************************************************
25 // 25 //
>> 26 // $Id: G4WentzelVIRelXSection.cc 74581 2013-10-15 12:03:25Z gcosmo $
26 // 27 //
27 // ------------------------------------------- 28 // -------------------------------------------------------------------
28 // 29 //
29 // GEANT4 Class file 30 // GEANT4 Class file
30 // 31 //
31 // 32 //
32 // File name: G4WentzelVIRelXSection 33 // File name: G4WentzelVIRelXSection
33 // 34 //
34 // Author: V.Ivanchenko 35 // Author: V.Ivanchenko
35 // 36 //
36 // Creation date: 08.06.2012 from G4WentzelOKa 37 // Creation date: 08.06.2012 from G4WentzelOKandVIxSection
37 // 38 //
38 // Modifications: 39 // Modifications:
39 // 40 //
40 // 41 //
41 42
42 // ------------------------------------------- 43 // -------------------------------------------------------------------
43 // 44 //
44 45
45 //....oooOO0OOooo........oooOO0OOooo........oo 46 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
46 //....oooOO0OOooo........oooOO0OOooo........oo 47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
47 48
48 #include "G4WentzelVIRelXSection.hh" 49 #include "G4WentzelVIRelXSection.hh"
>> 50 #include "G4PhysicalConstants.hh"
>> 51 #include "G4SystemOfUnits.hh"
>> 52 #include "Randomize.hh"
>> 53 #include "G4Electron.hh"
>> 54 #include "G4Positron.hh"
>> 55 #include "G4Proton.hh"
>> 56 #include "G4LossTableManager.hh"
>> 57 #include "G4Log.hh"
49 58
50 //....oooOO0OOooo........oooOO0OOooo........oo 59 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
51 60
52 G4WentzelVIRelXSection::G4WentzelVIRelXSection << 61 G4double G4WentzelVIRelXSection::ScreenRSquare[] = {0.0};
>> 62 G4double G4WentzelVIRelXSection::FormFactor[] = {0.0};
>> 63
>> 64 using namespace std;
>> 65
>> 66 G4WentzelVIRelXSection::G4WentzelVIRelXSection() :
>> 67 numlimit(0.1),
>> 68 nwarnings(0),
>> 69 nwarnlimit(50),
>> 70 alpha2(fine_structure_const*fine_structure_const)
>> 71 {
>> 72 fNistManager = G4NistManager::Instance();
>> 73 fG4pow = G4Pow::GetInstance();
>> 74 theElectron = G4Electron::Electron();
>> 75 thePositron = G4Positron::Positron();
>> 76 theProton = G4Proton::Proton();
>> 77 lowEnergyLimit = 1.0*eV;
>> 78 G4double p0 = electron_mass_c2*classic_electr_radius;
>> 79 coeff = twopi*p0*p0;
>> 80 particle = 0;
>> 81
>> 82 // Thomas-Fermi screening radii
>> 83 // Formfactors from A.V. Butkevich et al., NIM A 488 (2002) 282
>> 84
>> 85 if(0.0 == ScreenRSquare[0]) {
>> 86 G4double a0 = electron_mass_c2/0.88534;
>> 87 G4double constn = 6.937e-6/(MeV*MeV);
>> 88
>> 89 ScreenRSquare[0] = alpha2*a0*a0;
>> 90 for(G4int j=1; j<100; ++j) {
>> 91 G4double x = a0*fG4pow->Z13(j);
>> 92 //ScreenRSquare[j] = 0.5*(1 + exp(-j*j*0.001))*alpha2*x*x;
>> 93 ScreenRSquare[j] = 0.5*alpha2*x*x;
>> 94 x = fNistManager->GetA27(j);
>> 95 FormFactor[j] = constn*x*x;
>> 96 }
>> 97 }
>> 98 currentMaterial = 0;
>> 99 elecXSRatio = factB = factD = formfactA = screenZ = 0.0;
>> 100 cosTetMaxElec = cosTetMaxNuc = invbeta2 = kinFactor = gam0pcmp = pcmp2 = 1.0;
>> 101
>> 102 factB1= 0.5*CLHEP::pi*fine_structure_const;
>> 103
>> 104 Initialise(theElectron, 1.0);
>> 105 targetMass = proton_mass_c2;
>> 106 }
53 107
54 //....oooOO0OOooo........oooOO0OOooo........oo 108 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
55 109
56 G4WentzelVIRelXSection::~G4WentzelVIRelXSectio << 110 G4WentzelVIRelXSection::~G4WentzelVIRelXSection()
>> 111 {}
57 112
58 //....oooOO0OOooo........oooOO0OOooo........oo 113 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59 114
60 G4double G4WentzelVIRelXSection::SetupKinemati << 115 void G4WentzelVIRelXSection::Initialise(const G4ParticleDefinition* p,
61 cons << 116 G4double CosThetaLim)
62 { 117 {
63 if(kinEnergy != tkin || mat != currentMateri << 118 SetupParticle(p);
>> 119 tkin = mom2 = momCM2 = 0.0;
>> 120 ecut = etag = DBL_MAX;
>> 121 targetZ = 0;
>> 122 cosThetaMax = CosThetaLim;
>> 123 G4double a =
>> 124 G4LossTableManager::Instance()->FactorForAngleLimit()*CLHEP::hbarc/CLHEP::fermi;
>> 125 factorA2 = 0.5*a*a;
>> 126 currentMaterial = 0;
>> 127 }
64 128
65 currentMaterial = mat; << 129 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
66 tkin = kinEnergy; << 130
67 G4double momLab2 = tkin*(tkin + 2.0*mass) << 131 void G4WentzelVIRelXSection::SetupParticle(const G4ParticleDefinition* p)
68 << 132 {
69 G4double etot = tkin + mass; << 133 particle = p;
70 G4double ptot = std::sqrt(momLab2); << 134 mass = particle->GetPDGMass();
71 G4double m12 = mass*mass; << 135 spin = particle->GetPDGSpin();
72 << 136 if(0.0 != spin) { spin = 0.5; }
73 // relativistic reduced mass from publucat << 137 G4double q = std::fabs(particle->GetPDGCharge()/eplus);
74 // A.P. Martynenko, R.N. Faustov, Teoret. << 138 chargeSquare = q*q;
75 << 139 charge3 = chargeSquare*q;
76 //incident particle & target nucleus << 140 tkin = 0.0;
77 G4double Ecm = std::sqrt(m12 + targetMass* << 141 currentMaterial = 0;
78 G4double mu_rel = mass*targetMass/Ecm; << 142 targetZ = 0;
79 G4double momCM = ptot*targetMass/Ecm; <<
80 // relative system <<
81 mom2 = momCM*momCM; <<
82 invbeta2 = 1.0 + mu_rel*mu_rel/mom2; <<
83 <<
84 factB = spin/invbeta2; <<
85 factD = std::sqrt(mom2)/targetMass; <<
86 cosTetMaxNuc = isCombined ? <<
87 std::max(cosThetaMax, 1.-factorA2*mat->G <<
88 : cosThetaMax; <<
89 } <<
90 return cosTetMaxNuc; <<
91 } 143 }
92 144
>> 145 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 146
>> 147 G4double
>> 148 G4WentzelVIRelXSection::SetupTarget(G4int Z, G4double cut)
>> 149 {
>> 150 G4double cosTetMaxNuc2 = cosTetMaxNuc;
>> 151 if(Z != targetZ || tkin != etag) {
>> 152 etag = tkin;
>> 153 targetZ = Z;
>> 154 if(targetZ > 99) { targetZ = 99; }
>> 155 SetTargetMass(fNistManager->GetAtomicMassAmu(targetZ)*CLHEP::amu_c2);
>> 156 //G4double tmass2 = targetMass*targetMass;
>> 157 //G4double etot = tkin + mass;
>> 158 //G4double invmass2 = mass*mass + tmass2 + 2*etot*targetMass;
>> 159 //momCM2 = mom2*tmass2/invmass2;
>> 160 //gam0pcmp = (etot + targetMass)*targetMass/invmass2;
>> 161 //pcmp2 = tmass2/invmass2;
>> 162
>> 163 kinFactor = coeff*targetZ*chargeSquare*invbeta2/mom2;
>> 164
>> 165 screenZ = ScreenRSquare[targetZ]/mom2;
>> 166 if(Z > 1) {
>> 167 screenZ *= std::min(Z*1.13,1.13 +3.76*Z*Z*invbeta2*alpha2*chargeSquare);
>> 168 /*
>> 169 if(mass > MeV) {
>> 170 screenZ *= std::min(Z*1.13,1.13 +3.76*Z*Z*invbeta2*alpha2*chargeSquare);
>> 171 } else {
>> 172 G4double tau = tkin/mass;
>> 173 // screenZ *= std::min(Z*invbeta2,
>> 174 screenZ *= std::min(Z*1.13,
>> 175 (1.13 +3.76*Z*Z*invbeta2*alpha2*std::sqrt(tau/(tau + fG4pow->Z23(Z)))));
>> 176 }
>> 177 */
>> 178 }
>> 179 if(targetZ == 1 && cosTetMaxNuc2 < 0.0 && particle == theProton) {
>> 180 cosTetMaxNuc2 = 0.0;
>> 181 }
>> 182 formfactA = FormFactor[targetZ]*mom2;
>> 183
>> 184 cosTetMaxElec = 1.0;
>> 185 ComputeMaxElectronScattering(cut);
>> 186 }
>> 187 return cosTetMaxNuc2;
>> 188 }
>> 189
93 //....oooOO0OOooo........oooOO0OOooo........oo 190 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
94 191
>> 192 G4double
>> 193 G4WentzelVIRelXSection::ComputeTransportCrossSectionPerAtom(G4double cosTMax)
>> 194 {
>> 195 G4double xsec = 0.0;
>> 196 if(cosTMax >= 1.0) { return xsec; }
>> 197
>> 198 G4double xSection = 0.0;
>> 199 G4double x = 0;
>> 200 G4double y = 0;
>> 201 G4double x1= 0;
>> 202 G4double x2= 0;
>> 203 G4double xlog = 0.0;
>> 204
>> 205 G4double costm = std::max(cosTMax,cosTetMaxElec);
>> 206 G4double fb = screenZ*factB;
>> 207
>> 208 // scattering off electrons
>> 209 if(costm < 1.0) {
>> 210 x = (1.0 - costm)/screenZ;
>> 211 if(x < numlimit) {
>> 212 x2 = 0.5*x*x;
>> 213 y = x2*(1.0 - 1.3333333*x + 3*x2);
>> 214 if(0.0 < factB) { y -= fb*x2*x*(0.6666667 - x); }
>> 215 } else {
>> 216 x1= x/(1 + x);
>> 217 xlog = G4Log(1.0 + x);
>> 218 y = xlog - x1;
>> 219 if(0.0 < factB) { y -= fb*(x + x1 - 2*xlog); }
>> 220 }
>> 221
>> 222 if(y < 0.0) {
>> 223 ++nwarnings;
>> 224 if(nwarnings < nwarnlimit) {
>> 225 G4cout << "G4WentzelVIRelXSection::ComputeTransportCrossSectionPerAtom scattering on e- <0"
>> 226 << G4endl;
>> 227 G4cout << "y= " << y
>> 228 << " e(MeV)= " << tkin << " p(MeV/c)= " << sqrt(mom2)
>> 229 << " Z= " << targetZ << " "
>> 230 << particle->GetParticleName() << G4endl;
>> 231 G4cout << " 1-costm= " << 1.0-costm << " screenZ= " << screenZ
>> 232 << " x= " << x << G4endl;
>> 233 }
>> 234 y = 0.0;
>> 235 }
>> 236 xSection = y;
>> 237 }
>> 238 /*
>> 239 G4cout << "G4WentzelVI:XS per A " << " Z= " << targetZ
>> 240 << " e(MeV)= " << tkin/MeV << " XSel= " << xSection
>> 241 << " cut(MeV)= " << ecut/MeV
>> 242 << " zmaxE= " << (1.0 - cosTetMaxElec)/screenZ
>> 243 << " zmaxN= " << (1.0 - cosThetaMax)/screenZ
>> 244 << " 1-costm= " << 1.0 - cosThetaMax << G4endl;
>> 245 */
>> 246 // scattering off nucleus
>> 247 if(cosTMax < 1.0) {
>> 248 x = (1.0 - cosTMax)/screenZ;
>> 249 if(x < numlimit) {
>> 250 x2 = 0.5*x*x;
>> 251 y = x2*(1.0 - 1.3333333*x + 3*x2);
>> 252 if(0.0 < factB) { y -= fb*x2*x*(0.6666667 - x); }
>> 253 } else {
>> 254 x1= x/(1 + x);
>> 255 xlog = G4Log(1.0 + x);
>> 256 y = xlog - x1;
>> 257 if(0.0 < factB) { y -= fb*(x + x1 - 2*xlog); }
>> 258 }
>> 259
>> 260 if(y < 0.0) {
>> 261 ++nwarnings;
>> 262 if(nwarnings < nwarnlimit) {
>> 263 G4cout << "G4WentzelVIRelXSection::ComputeTransportCrossSectionPerAtom scattering on e- <0"
>> 264 << G4endl;
>> 265 G4cout << "y= " << y
>> 266 << " e(MeV)= " << tkin << " Z= " << targetZ << " "
>> 267 << particle->GetParticleName() << G4endl;
>> 268 G4cout << " formfactA= " << formfactA << " screenZ= " << screenZ
>> 269 << " x= " << " x1= " << x1 <<G4endl;
>> 270 }
>> 271 y = 0.0;
>> 272 }
>> 273 xSection += y*targetZ;
>> 274 }
>> 275 xSection *= kinFactor;
>> 276 /*
>> 277 G4cout << "Z= " << targetZ << " XStot= " << xSection/barn
>> 278 << " screenZ= " << screenZ << " formF= " << formfactA
>> 279 << " for " << particle->GetParticleName()
>> 280 << " m= " << mass << " 1/v= " << sqrt(invbeta2) << " p= " << sqrt(mom2)
>> 281 << " x= " << x
>> 282 << G4endl;
>> 283 */
>> 284 return xSection;
>> 285 }
>> 286
>> 287 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 288
>> 289 G4ThreeVector
>> 290 G4WentzelVIRelXSection::SampleSingleScattering(G4double cosTMin,
>> 291 G4double cosTMax,
>> 292 G4double elecRatio)
>> 293 {
>> 294 G4ThreeVector v(0.0,0.0,1.0);
>> 295
>> 296 G4double formf = formfactA;
>> 297 G4double cost1 = cosTMin;
>> 298 G4double cost2 = cosTMax;
>> 299 if(elecRatio > 0.0) {
>> 300 if(G4UniformRand() <= elecRatio) {
>> 301 formf = 0.0;
>> 302 cost1 = std::max(cost1,cosTetMaxElec);
>> 303 cost2 = std::max(cost2,cosTetMaxElec);
>> 304 }
>> 305 }
>> 306 if(cost1 < cost2) { return v; }
>> 307
>> 308 G4double w1 = 1. - cost1 + screenZ;
>> 309 G4double w2 = 1. - cost2 + screenZ;
>> 310 G4double z1 = w1*w2/(w1 + G4UniformRand()*(w2 - w1)) - screenZ;
>> 311
>> 312 //G4double fm = 1.0 + formf*z1/(1.0 + (mass + tkin)*z1/targetMass);
>> 313 G4double fm = 1.0 + formf*z1;
>> 314 //G4double grej = (1. - z1*factB)/( (1.0 + z1*factD)*fm*fm );
>> 315 G4double grej = (1. - z1*factB + factB1*targetZ*sqrt(z1*factB)*(2 - z1))/( (1.0 + z1*factD)*fm*fm );
>> 316 // "false" scattering
>> 317 if( G4UniformRand() > grej ) { return v; }
>> 318 // }
>> 319 G4double cost = 1.0 - z1;
>> 320
>> 321 if(cost > 1.0) { cost = 1.0; }
>> 322 else if(cost < -1.0) { cost =-1.0; }
>> 323 G4double sint = sqrt((1.0 - cost)*(1.0 + cost));
>> 324 //G4cout << "sint= " << sint << G4endl;
>> 325 G4double phi = twopi*G4UniformRand();
>> 326 G4double vx1 = sint*cos(phi);
>> 327 G4double vy1 = sint*sin(phi);
>> 328
>> 329 // only direction is changed
>> 330 v.set(vx1,vy1,cost);
>> 331 return v;
>> 332 }
>> 333
>> 334 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
>> 335
>> 336 void
>> 337 G4WentzelVIRelXSection::ComputeMaxElectronScattering(G4double cutEnergy)
>> 338 {
>> 339 if(mass > MeV) {
>> 340 G4double ratio = electron_mass_c2/mass;
>> 341 G4double tau = tkin/mass;
>> 342 G4double tmax = 2.0*electron_mass_c2*tau*(tau + 2.)/
>> 343 (1.0 + 2.0*ratio*(tau + 1.0) + ratio*ratio);
>> 344 //tmax = std::min(tmax, targetZ*targetZ*10*eV);
>> 345 cosTetMaxElec = 1.0 - std::min(cutEnergy, tmax)*electron_mass_c2/mom2;
>> 346 } else {
>> 347
>> 348 G4double tmax = tkin;
>> 349 if(particle == theElectron) { tmax *= 0.5; }
>> 350 //tmax = std::min(tmax, targetZ*targetZ*10*eV);
>> 351 G4double t = std::min(cutEnergy, tmax);
>> 352 G4double mom21 = t*(t + 2.0*electron_mass_c2);
>> 353 G4double t1 = tkin - t;
>> 354 //G4cout <<"tkin=" <<tkin<<" tmax= "<<tmax<<" t= "
>> 355 //<<t<< " t1= "<<t1<<" cut= "<<ecut<<G4endl;
>> 356 if(t1 > 0.0) {
>> 357 G4double mom22 = t1*(t1 + 2.0*mass);
>> 358 G4double ctm = (mom2 + mom22 - mom21)*0.5/sqrt(mom2*mom22);
>> 359 if(ctm < 1.0) { cosTetMaxElec = ctm; }
>> 360 if(particle == theElectron && cosTetMaxElec < 0.0) { cosTetMaxElec = 0.0; }
>> 361 }
>> 362 }
>> 363 }
>> 364
>> 365 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
95 366