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>> 26 // $Id: G4eBremsstrahlungRelModel.cc 75582 2013-11-04 12:13:01Z gcosmo $
26 // 27 //
27 // ------------------------------------------- 28 // -------------------------------------------------------------------
28 // 29 //
29 // GEANT4 Class file 30 // GEANT4 Class file
30 // 31 //
31 // 32 //
32 // File name: G4eBremsstrahlungRelModel 33 // File name: G4eBremsstrahlungRelModel
33 // 34 //
34 // Author: Andreas Schaelicke << 35 // Author: Andreas Schaelicke
35 // 36 //
36 // Creation date: 12.08.2008 37 // Creation date: 12.08.2008
37 // 38 //
38 // Modifications: 39 // Modifications:
39 // 40 //
40 // 13.11.08 add SetLPMflag and SetLPMconsta 41 // 13.11.08 add SetLPMflag and SetLPMconstant methods
41 // 13.11.08 change default LPMconstant valu 42 // 13.11.08 change default LPMconstant value
42 // 13.10.10 add angular distributon interfa 43 // 13.10.10 add angular distributon interface (VI)
43 // 31.05.16 change LPMconstant such that it <<
44 // that consistent to Migdal's one <<
45 // computation; better agreement w <<
46 // 15.07.18 improved LPM suppression functi <<
47 // steps), code cleanup and optimi <<
48 // model related comments, consist <<
49 // 44 //
50 // Main References: 45 // Main References:
51 // Y.-S.Tsai, Rev. Mod. Phys. 46 (1974) 815; << 46 // Y.-S.Tsai, Rev. Mod. Phys. 46 (1974) 815; Rev. Mod. Phys. 49 (1977) 421.
52 // S.Klein, Rev. Mod. Phys. 71 (1999) 1501. 47 // S.Klein, Rev. Mod. Phys. 71 (1999) 1501.
53 // T.Stanev et.al., Phys. Rev. D25 (1982) 129 48 // T.Stanev et.al., Phys. Rev. D25 (1982) 1291.
54 // M.L.Ter-Mikaelian, High-energy Electromagn << 49 // M.L.Ter-Mikaelian, High-energy Electromagnetic Processes in Condensed Media, Wiley, 1972.
55 // Wiley, 1972. <<
56 // 50 //
57 // ------------------------------------------- 51 // -------------------------------------------------------------------
58 // 52 //
>> 53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 54 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59 55
60 #include "G4eBremsstrahlungRelModel.hh" 56 #include "G4eBremsstrahlungRelModel.hh"
61 #include "G4PhysicalConstants.hh" 57 #include "G4PhysicalConstants.hh"
62 #include "G4SystemOfUnits.hh" 58 #include "G4SystemOfUnits.hh"
63 #include "G4Electron.hh" 59 #include "G4Electron.hh"
>> 60 #include "G4Positron.hh"
64 #include "G4Gamma.hh" 61 #include "G4Gamma.hh"
65 #include "Randomize.hh" 62 #include "Randomize.hh"
66 #include "G4Material.hh" 63 #include "G4Material.hh"
67 #include "G4Element.hh" 64 #include "G4Element.hh"
68 #include "G4ElementVector.hh" 65 #include "G4ElementVector.hh"
>> 66 #include "G4ProductionCutsTable.hh"
69 #include "G4ParticleChangeForLoss.hh" 67 #include "G4ParticleChangeForLoss.hh"
>> 68 #include "G4LossTableManager.hh"
70 #include "G4ModifiedTsai.hh" 69 #include "G4ModifiedTsai.hh"
71 #include "G4Exp.hh" << 70 #include "G4DipBustGenerator.hh"
72 #include "G4Log.hh" << 71
73 #include "G4Pow.hh" << 72 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
74 #include "G4EmParameters.hh" << 73
75 #include "G4AutoLock.hh" << 74 const G4double
76 #include <thread> << 75 G4eBremsstrahlungRelModel::xgi[]={ 0.0199, 0.1017, 0.2372, 0.4083,
77 << 76 0.5917, 0.7628, 0.8983, 0.9801 };
78 const G4int G4eBremsstrahlungRelModel::gMaxZet << 77 const G4double
79 << 78 G4eBremsstrahlungRelModel::wgi[]={ 0.0506, 0.1112, 0.1569, 0.1813,
80 // constant DCS factor: 16\alpha r_0^2/3 << 79 0.1813, 0.1569, 0.1112, 0.0506 };
81 const G4double G4eBremsstrahlungRelModel::gBre << 80 const G4double
82 = 16. * CLHEP::fine_structure_const * CLHEP: << 81 G4eBremsstrahlungRelModel::Fel_light[] = {0., 5.31 , 4.79 , 4.74 , 4.71};
83 * CLHEP::classic_electr_radius/3.; << 82 const G4double
84 << 83 G4eBremsstrahlungRelModel::Finel_light[] = {0., 6.144 , 5.621 , 5.805 , 5.924};
85 // Migdal's constant: 4\pi r_0*electron_reduce << 84
86 const G4double G4eBremsstrahlungRelModel::gMig << 85 using namespace std;
87 = 4. * CLHEP::pi * CLHEP::classic_electr_rad << 86
88 * CLHEP::electron_Compton_length * CLHEP:: << 87 G4eBremsstrahlungRelModel::G4eBremsstrahlungRelModel(
89 << 88 const G4ParticleDefinition* p, const G4String& nam)
90 // LPM constant: \alpha(mc^2)^2/(4\pi*\hbar c) << 89 : G4VEmModel(nam),
91 const G4double G4eBremsstrahlungRelModel::gLPM << 90 particle(0),
92 = CLHEP::fine_structure_const * CLHEP::elect << 91 bremFactor(fine_structure_const*classic_electr_radius*classic_electr_radius*16./3.),
93 * CLHEP::electron_mass_c2 / (4. * CLHEP::p << 92 isElectron(true),
94 << 93 fMigdalConstant(classic_electr_radius*electron_Compton_length*electron_Compton_length*4.0*pi),
95 // abscissas and weights of an 8 point Gauss-L << 94 fLPMconstant(fine_structure_const*electron_mass_c2*electron_mass_c2/(4.*pi*hbarc)*0.5),
96 // for numerical integration on [0,1] << 95 fXiLPM(0), fPhiLPM(0), fGLPM(0),
97 const G4double G4eBremsstrahlungRelModel::gXGL << 96 use_completescreening(false),isInitialised(false)
98 1.98550718e-02, 1.01666761e-01, 2.37233795e- <<
99 5.91717321e-01, 7.62766205e-01, 8.98333239e- <<
100 }; <<
101 const G4double G4eBremsstrahlungRelModel::gWGL <<
102 5.06142681e-02, 1.11190517e-01, 1.56853323e- <<
103 1.81341892e-01, 1.56853323e-01, 1.11190517e- <<
104 }; <<
105 <<
106 // elastic and inelatic radiation logarithms f <<
107 // Thomas-Fermi model doesn't work): computed <<
108 const G4double G4eBremsstrahlungRelModel::gFel <<
109 0.0, 5.3104, 4.7935, 4.7402, 4.7112, 4.6694, <<
110 }; <<
111 const G4double G4eBremsstrahlungRelModel::gFin <<
112 0.0, 5.9173, 5.6125, 5.5377, 5.4728, 5.4174, <<
113 }; <<
114 <<
115 // LPM supression functions evaluated at initi <<
116 std::shared_ptr<G4eBremsstrahlungRelModel::LPM <<
117 { <<
118 // We have to use shared pointer for the LPM <<
119 // by the G4eBremsstrahlungRelModel used in <<
120 // model is owned (well deleted) by (at leas <<
121 // a G4SeltzerBergerModel which is owned by <<
122 // which owned by a G4ThreadLocalSingleton<G <<
123 // which is a static global and thus deleted <<
124 // is deleted. <<
125 static auto _instance = std::make_shared<G4e <<
126 return _instance; <<
127 } <<
128 <<
129 // special data structure per element i.e. per <<
130 std::shared_ptr<std::vector<G4eBremsstrahlungR <<
131 { <<
132 // Same code comment as for gLPMFuncs. <<
133 static auto _instance = std::make_shared<std <<
134 return _instance; <<
135 } <<
136 <<
137 static std::once_flag applyOnce; <<
138 <<
139 namespace <<
140 { <<
141 G4Mutex theBremRelMutex = G4MUTEX_INITIALIZE <<
142 } <<
143 <<
144 G4eBremsstrahlungRelModel::G4eBremsstrahlungRe <<
145 <<
146 : G4VEmModel(nam), fLPMFuncs(gLPMFuncs()), fEl <<
147 { 97 {
148 fGammaParticle = G4Gamma::Gamma(); << 98 fParticleChange = 0;
149 // << 99 theGamma = G4Gamma::Gamma();
150 fLowestKinEnergy = 1.0*CLHEP::MeV; << 100
151 SetLowEnergyLimit(fLowestKinEnergy); << 101 lowestKinEnergy = 1.0*MeV;
152 // << 102 SetLowEnergyLimit(lowestKinEnergy);
153 fLPMEnergyThreshold = 1.e+39; << 103
154 fLPMEnergy = 0.; << 104 nist = G4NistManager::Instance();
155 SetAngularDistribution(new G4ModifiedTsai()) << 105
156 // << 106 SetLPMFlag(true);
157 if (nullptr != p) { << 107 //SetAngularDistribution(new G4ModifiedTsai());
158 SetParticle(p); << 108 SetAngularDistribution(new G4DipBustGenerator());
159 } << 109
>> 110 particleMass = kinEnergy = totalEnergy = currentZ = z13 = z23 = lnZ = Fel
>> 111 = Finel = fCoulomb = fMax = densityFactor = densityCorr = lpmEnergy
>> 112 = xiLPM = phiLPM = gLPM = klpm = kp = 0.0;
>> 113
>> 114 energyThresholdLPM = 1.e39;
>> 115
>> 116 InitialiseConstants();
>> 117 if(p) { SetParticle(p); }
160 } 118 }
161 119
>> 120 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 121
>> 122 void G4eBremsstrahlungRelModel::InitialiseConstants()
>> 123 {
>> 124 facFel = G4Log(184.15);
>> 125 facFinel = G4Log(1194.);
>> 126
>> 127 preS1 = 1./(184.15*184.15);
>> 128 logTwo = G4Log(2.);
>> 129 }
>> 130
>> 131 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 132
162 G4eBremsstrahlungRelModel::~G4eBremsstrahlungR 133 G4eBremsstrahlungRelModel::~G4eBremsstrahlungRelModel()
163 { 134 {
164 if (fIsInitializer) { << 135 }
165 // clear ElementData container << 136
166 for (auto const & ptr : *fElementData) { d << 137 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
167 fElementData->clear(); << 138
168 // clear LPMFunctions (if any) << 139 void G4eBremsstrahlungRelModel::SetParticle(const G4ParticleDefinition* p)
169 if (fLPMFuncs->fIsInitialized) { << 140 {
170 fLPMFuncs->fLPMFuncG.clear(); << 141 particle = p;
171 fLPMFuncs->fLPMFuncPhi.clear(); << 142 particleMass = p->GetPDGMass();
172 fLPMFuncs->fIsInitialized = false; << 143 if(p == G4Electron::Electron()) { isElectron = true; }
173 } << 144 else { isElectron = false;}
>> 145 }
>> 146
>> 147 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 148
>> 149 void G4eBremsstrahlungRelModel::SetupForMaterial(const G4ParticleDefinition*,
>> 150 const G4Material* mat,
>> 151 G4double kineticEnergy)
>> 152 {
>> 153 densityFactor = mat->GetElectronDensity()*fMigdalConstant;
>> 154 lpmEnergy = mat->GetRadlen()*fLPMconstant;
>> 155
>> 156 // Threshold for LPM effect (i.e. below which LPM hidden by density effect)
>> 157 if (LPMFlag()) {
>> 158 energyThresholdLPM=sqrt(densityFactor)*lpmEnergy;
>> 159 } else {
>> 160 energyThresholdLPM=1.e39; // i.e. do not use LPM effect
174 } 161 }
>> 162 // calculate threshold for density effect
>> 163 kinEnergy = kineticEnergy;
>> 164 totalEnergy = kineticEnergy + particleMass;
>> 165 densityCorr = densityFactor*totalEnergy*totalEnergy;
>> 166
>> 167 // define critical gamma energies (important for integration/dicing)
>> 168 klpm=totalEnergy*totalEnergy/lpmEnergy;
>> 169 kp=sqrt(densityCorr);
175 } 170 }
176 171
>> 172
>> 173 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 174
177 void G4eBremsstrahlungRelModel::Initialise(con 175 void G4eBremsstrahlungRelModel::Initialise(const G4ParticleDefinition* p,
178 con << 176 const G4DataVector& cuts)
179 { 177 {
180 // parameters in each thread << 178 if(p) { SetParticle(p); }
181 if (fPrimaryParticle != p) { << 179
182 SetParticle(p); << 180 currentZ = 0.;
183 } << 181
184 fUseLPM = G4EmParameters::Instance()->LPM(); << 182 if(IsMaster()) { InitialiseElementSelectors(p, cuts); }
185 fCurrentIZ = 0; << 183
186 << 184 if(isInitialised) { return; }
187 // init static element data and precompute L << 185 fParticleChange = GetParticleChangeForLoss();
188 std::call_once(applyOnce, [this]() { fIsInit << 186 isInitialised = true;
189 <<
190 // for all treads and derived classes <<
191 if (fIsInitializer || fElementData->empty()) <<
192 G4AutoLock l(&theBremRelMutex); <<
193 if (fElementData->empty()) { <<
194 fElementData->resize(gMaxZet+1, nullptr) <<
195 } <<
196 InitialiseElementData(); <<
197 InitLPMFunctions(); <<
198 l.unlock(); <<
199 } <<
200 <<
201 // element selectors are initialized in the <<
202 if (IsMaster()) { <<
203 InitialiseElementSelectors(p, cuts); <<
204 } <<
205 // initialisation in all threads <<
206 if (nullptr == fParticleChange) { <<
207 fParticleChange = GetParticleChangeForLoss <<
208 } <<
209 if (GetTripletModel()) { <<
210 GetTripletModel()->Initialise(p, cuts); <<
211 fIsScatOffElectron = true; <<
212 } <<
213 } 187 }
214 188
>> 189 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 190
215 void G4eBremsstrahlungRelModel::InitialiseLoca 191 void G4eBremsstrahlungRelModel::InitialiseLocal(const G4ParticleDefinition*,
216 << 192 G4VEmModel* masterModel)
217 { 193 {
218 SetElementSelectors(masterModel->GetElementS 194 SetElementSelectors(masterModel->GetElementSelectors());
219 } 195 }
220 196
221 void G4eBremsstrahlungRelModel::SetParticle(co << 197 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 198
>> 199 G4double
>> 200 G4eBremsstrahlungRelModel::MinPrimaryEnergy(const G4Material*,
>> 201 const G4ParticleDefinition*,
>> 202 G4double cut)
222 { 203 {
223 fPrimaryParticle = p; << 204 return std::max(lowestKinEnergy, cut);
224 fPrimaryParticleMass = p->GetPDGMass(); <<
225 fIsElectron = (p==G4Electron::Elect <<
226 } 205 }
227 206
228 // Sets kinematical variables like E_kin, E_t << 207 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
229 // variables like LPM energy and characteristi << 208
230 // k_p^2) for the Ter-Mikaelian suppression ef << 209 G4double G4eBremsstrahlungRelModel::ComputeDEDXPerVolume(
231 void G4eBremsstrahlungRelModel::SetupForMateri << 210 const G4Material* material,
232 << 211 const G4ParticleDefinition* p,
233 << 212 G4double kineticEnergy,
234 { << 213 G4double cutEnergy)
235 fDensityFactor = gMigdalConstant*mat->GetEle <<
236 fLPMEnergy = gLPMconstant*mat->GetRadlen <<
237 // threshold for LPM effect (i.e. below whic <<
238 if (fUseLPM) { <<
239 fLPMEnergyThreshold = std::sqrt(fDensityFa <<
240 } else { <<
241 fLPMEnergyThreshold = 1.e+39; // i.e. do <<
242 } <<
243 // calculate threshold for density effect: k <<
244 fPrimaryKinEnergy = kineticEnergy; <<
245 fPrimaryTotalEnergy = kineticEnergy+fPrimary <<
246 fDensityCorr = fDensityFactor*fPrimar <<
247 // set activation flag for LPM effects in th <<
248 fIsLPMActive = (fPrimaryTotalEnergy>fLPMEner <<
249 } <<
250 <<
251 // minimum primary (e-/e+) energy at which dis <<
252 G4double G4eBremsstrahlungRelModel::MinPrimary <<
253 <<
254 <<
255 { <<
256 return std::max(fLowestKinEnergy, cut); <<
257 } <<
258 <<
259 // Computes the restricted dE/dx as the approp <<
260 // element contributions that are computed by <<
261 G4double <<
262 G4eBremsstrahlungRelModel::ComputeDEDXPerVolum <<
263 <<
264 <<
265 <<
266 { 214 {
>> 215 if(!particle) { SetParticle(p); }
>> 216 if(kineticEnergy < LowEnergyLimit()) { return 0.0; }
>> 217 G4double cut = std::min(cutEnergy, kineticEnergy);
>> 218 if(cut == 0.0) { return 0.0; }
>> 219
>> 220 SetupForMaterial(particle, material,kineticEnergy);
>> 221
>> 222 const G4ElementVector* theElementVector = material->GetElementVector();
>> 223 const G4double* theAtomicNumDensityVector = material->GetAtomicNumDensityVector();
>> 224
267 G4double dedx = 0.0; 225 G4double dedx = 0.0;
268 if (nullptr == fPrimaryParticle) { << 226
269 SetParticle(p); << 227 // loop for elements in the material
270 } << 228 for (size_t i=0; i<material->GetNumberOfElements(); i++) {
271 if (kineticEnergy < LowEnergyLimit()) { << 229
272 return dedx; << 230 G4VEmModel::SetCurrentElement((*theElementVector)[i]);
273 } << 231 SetCurrentElement((*theElementVector)[i]->GetZ());
274 // maximum value of the dE/dx integral (the << 232
275 G4double tmax = std::min(cutEnergy, kineticE << 233 dedx += theAtomicNumDensityVector[i]*currentZ*currentZ*ComputeBremLoss(cut);
276 if (tmax == 0.0) { <<
277 return dedx; <<
278 } <<
279 // sets kinematical and material related var <<
280 SetupForMaterial(fPrimaryParticle, material, <<
281 // get element compositions of the material <<
282 const G4ElementVector* theElemVector = mater <<
283 const G4double* theAtomNumDensVector = mater <<
284 const std::size_t numberOfElements = theElem <<
285 // loop over the elements of the material an <<
286 // the restricted dE/dx by numerical integra <<
287 for (std::size_t ie = 0; ie < numberOfElemen <<
288 G4VEmModel::SetCurrentElement((*theElemVec <<
289 G4int zet = (*theElemVector)[ie]->GetZasIn <<
290 fCurrentIZ = std::min(zet, gMaxZet); <<
291 dedx += (zet*zet)*theAtomNumD <<
292 } <<
293 // apply the constant factor C/Z = 16\alpha <<
294 dedx *= gBremFactor; <<
295 return std::max(dedx,0.); <<
296 } <<
297 <<
298 // Computes the integral part of the restricte <<
299 // element (Z) by numerically integrating the <<
300 // k_min=0 and k_max = tmax = min[gamma-cut, e <<
301 // The numerical integration is done by dividi <<
302 // subintervals and an 8 pint GL integral (on <<
303 // inteval by tranforming k to alpha=k/E_t (E_ <<
304 // and each sub-interavl is transformed to [0, <<
305 // in xi(alpha) = xi(k) = [k/E_t-alpha_i]/delt <<
306 // the i = 1,2,..,n-th sub-interval so xi(k) i <<
307 // This transformation from 'k' to 'xi(k)' res <<
308 // of E_t*delta at each step. <<
309 // The restricted dE/dx = N int_{0}^{k_max} k* <<
310 // one with LPM and one without LPM effects (s <<
311 // the ds/dk(Z,k) but ds/dk(Z,k)*[F*k/C] is co <<
312 // (i) what we need here is ds/dk*k and not <<
313 // (ii) the Ter-Mikaelian suppression i.e. F <<
314 // (iii) the constant factor C (includes Z^2 <<
315 G4double G4eBremsstrahlungRelModel::ComputeBre <<
316 { <<
317 // number of intervals and integration step <<
318 const G4double alphaMax = tmax/fPrimaryTotal <<
319 const G4int nSub = (G4int)(20*alphaMa <<
320 const G4double delta = alphaMax/((G4doubl <<
321 // set minimum value of the first sub-inteva <<
322 G4double alpha_i = 0.0; <<
323 G4double dedxInteg = 0.0; <<
324 for (G4int l = 0; l < nSub; ++l) { <<
325 for (G4int igl = 0; igl < 8; ++igl) { <<
326 // compute the emitted photon energy k <<
327 const G4double k = (alpha_i+gXGL[igl]* <<
328 // compute the DCS value at k (without t <<
329 const G4double dcs = fIsLPMActive <<
330 ? ComputeRelDXSectio <<
331 : ComputeDXSectionPe <<
332 // account Ter-Mikaelian suppression: ti <<
333 dedxInteg += gWGL[igl]*dcs/(1.0+fDensity <<
334 } <<
335 // update sub-interval minimum value <<
336 alpha_i += delta; <<
337 } 234 }
338 // apply corrections due to variable transfo << 235 dedx *= bremFactor;
339 dedxInteg *= delta*fPrimaryTotalEnergy; << 236
340 return std::max(dedxInteg,0.); << 237
>> 238 return dedx;
341 } 239 }
342 240
343 // Computes restrected atomic cross section by << 241 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
344 // DCS between the proper kinematical limits a << 242
345 G4double G4eBremsstrahlungRelModel::ComputeCro << 243 G4double G4eBremsstrahlungRelModel::ComputeBremLoss(G4double cut)
346 << 244 {
347 << 245 G4double loss = 0.0;
348 << 246
349 << 247 // number of intervals and integration step
350 << 248 G4double vcut = cut/totalEnergy;
351 << 249 G4int n = (G4int)(20*vcut) + 3;
352 { << 250 G4double delta = vcut/G4double(n);
353 G4double crossSection = 0.0; << 251
354 if (nullptr == fPrimaryParticle) { << 252 G4double e0 = 0.0;
355 SetParticle(p); << 253 G4double xs;
356 } << 254
357 if (kineticEnergy < LowEnergyLimit()) { << 255 // integration
358 return crossSection; << 256 for(G4int l=0; l<n; l++) {
359 } << 257
360 // min/max kinetic energy limits of the DCS << 258 for(G4int i=0; i<8; i++) {
361 const G4double tmin = std::min(cut, kineticE << 259
362 const G4double tmax = std::min(maxEnergy, ki << 260 G4double eg = (e0 + xgi[i]*delta)*totalEnergy;
363 // zero restricted x-section if e- kinetic e << 261
364 if (tmin >= tmax) { << 262 if(totalEnergy > energyThresholdLPM) {
365 return crossSection; << 263 xs = ComputeRelDXSectionPerAtom(eg);
366 } << 264 } else {
367 fCurrentIZ = std::min(G4lrint(Z), gMaxZet); << 265 xs = ComputeDXSectionPerAtom(eg);
368 // integrate numerically (dependent part of) << 266 }
369 // a. integrate between tmin and kineticEner << 267 loss += wgi[i]*xs/(1.0 + densityCorr/(eg*eg));
370 crossSection = ComputeXSectionPerAtom(tmin); <<
371 // allow partial integration: only if maxEne <<
372 // b. integrate between tmax and kineticEner <<
373 // (so the result in this case is the integr <<
374 // maxEnergy) <<
375 if (tmax < kineticEnergy) { <<
376 crossSection -= ComputeXSectionPerAtom(tma <<
377 } <<
378 // multiply with the constant factors: 16\al <<
379 crossSection *= Z*Z*gBremFactor; <<
380 return std::max(crossSection, 0.); <<
381 } <<
382 <<
383 // Numerical integral of the (k dependent part <<
384 // k_max = E_k (where E_k is the kinetic energ <<
385 // minimum of energy of the emitted photon). <<
386 // transformed alpha(k) = ln(k/E_t) variable ( <<
387 // the primary e-). The integration range is d <<
388 // delta = [ln(k_min/E_t)-ln(k_max/E_t)]/n wid <<
389 // on [0,1] is applied on each sub-inteval so <<
390 // xi(alpha) = xi(k) = [ln(k/E_t)-alpha_i]/del <<
391 // (i-1)*delta for the i = 1,2,..,n-th sub-int <<
392 // sub-intevals. From the transformed xi, k(xi <<
393 // Since the integration is done in variable x <<
394 // transformation results in a multiplicative <<
395 // However, DCS differential in k is ~1/k so t <<
396 // becomes delta and the 1/k factor is dropped <<
397 // NOTE: <<
398 // - LPM suppression is accounted above thre <<
399 // flag is set in SetUpForMaterial() => 2 <<
400 // - Ter-Mikaelian suppression is always acc <<
401 G4double G4eBremsstrahlungRelModel::ComputeXSe <<
402 { <<
403 G4double xSection = 0.0; <<
404 const G4double alphaMin = G4Log(tmin/fPrimar <<
405 const G4double alphaMax = G4Log(fPrimaryKinE <<
406 const G4int nSub = std::max((G4int)(0.45*alp <<
407 const G4double delta = alphaMax/((G4double)n <<
408 // set minimum value of the first sub-inteva <<
409 G4double alpha_i = alphaMin; <<
410 for (G4int l = 0; l < nSub; ++l) { <<
411 for (G4int igl = 0; igl < 8; ++igl) { <<
412 // compute the emitted photon energy k <<
413 const G4double k = G4Exp(alpha_i+gXGL[ <<
414 // compute the DCS value at k (without t <<
415 const G4double dcs = fIsLPMActive <<
416 ? ComputeRelDXSectio <<
417 : ComputeDXSectionPe <<
418 // account Ter-Mikaelian suppression: ti <<
419 xSection += gWGL[igl]*dcs/(1.0+fDensityC <<
420 } <<
421 // update sub-interval minimum value <<
422 alpha_i += delta; <<
423 } <<
424 // apply corrections due to variable transfo <<
425 xSection *= delta; <<
426 // final check <<
427 return std::max(xSection, 0.); <<
428 } <<
429 <<
430 // DCS WITH LPM EFFECT: complete screening apr <<
431 // ds/dk(Z,k) = C/[F*k]*{ Xi(s*F)*[y^2*G/4 +(1 <<
432 // +(1-y)*[1+1/Z]/12} <<
433 // Xi(s),G(s), Phi(s) are LPM suppression func <<
434 // <<
435 // LPM SUPPRESSION: The 's' is the suppression <<
436 // 1+(k_p/k)^2 with k_p = hbar*w_p*E/(m*c^2) i <<
437 // dependent constant. F accounts the Ter-Mika <<
438 // transition in the emitted photon energy. Al <<
439 // goes to 0 when s goes to 0 and goes to 1 wh <<
440 // So evaluating the LPM suppression functions <<
441 // smooth transition depending on the emitted <<
442 // smoothly turned off i.e. Xi(sF)=G(sF)=Phi(s <<
443 // and sF ~ s when k >> k_p since F ~ 1 in tha <<
444 // HERE, ds/dk(Z,k)*[F*k/C] is computed since: <<
445 // (i) DCS ~ 1/k factor will disappear due <<
446 // v(k)=ln(k/E_t) -> dk/dv=E_t*e^v=k -> <<
447 // would cnacell out the 1/k factor => <<
448 // (ii) the constant factor C and Z don't de <<
449 // (iii) the 1/F(k) factor is accounted in th <<
450 // tion computation) or implicitly thro <<
451 // (in the final state sampling algorit <<
452 // COMPLETE SCREENING: see more at the DCS wit <<
453 G4double <<
454 G4eBremsstrahlungRelModel::ComputeRelDXSection <<
455 { <<
456 G4double dxsec = 0.0; <<
457 if (gammaEnergy < 0.) { <<
458 return dxsec; <<
459 } <<
460 const G4double y = gammaEnergy/fPrimaryT <<
461 const G4double onemy = 1.-y; <<
462 const G4double dum0 = 0.25*y*y; <<
463 // evaluate LPM functions (combined with the <<
464 G4double funcGS, funcPhiS, funcXiS; <<
465 ComputeLPMfunctions(funcXiS, funcGS, funcPhi <<
466 const ElementData* elDat = (*fElementData)[f <<
467 const G4double term1 = funcXiS*(dum0*fun <<
468 dxsec = term1*elDat->fZFactor1+onemy*elDat-> <<
469 // <<
470 if (fIsScatOffElectron) { <<
471 fSumTerm = dxsec; <<
472 fNucTerm = term1*elDat->fZFactor11 + onemy <<
473 } <<
474 return std::max(dxsec,0.0); <<
475 } <<
476 <<
477 // DCS WITHOUT LPM EFFECT: DCS with sceening ( <<
478 // ds/dk(Z,k)=C/[F*k]*{(1-y+3*y^2/4)*[(0.25*ph <<
479 // -2*ln(Z)/3)/Z]+ (1-y)*[(phi1(g)-phi2(g))+(p <<
480 // where f_c(Z) is the Coulomb correction fact <<
481 // psi2(e) are coherent and incoherent screeni <<
482 // model of the atom, the screening functions <<
483 // depend on Z (not explicitly). These numeric <<
484 // approximated as Tsai Eqs. [3.38-3.41] with <<
485 // e=epsilon given by Tsai Eqs. [3.30 and 3.31 <<
486 // ComputeScreeningFunctions()). Note, that in <<
487 // g = e = 0 => 0.25*phi1(0)-ln(Z)/3 = ln(184. <<
488 // 0.25*psi1(0)-2*ln(Z)/3=ln(1193.923/Z^(2/3)) <<
489 // psi1(0)-psi2(0) = 2/3 so the DCS in complet <<
490 // COMPLETE SCREENING: <<
491 // ds/dk(Z,k)=C/k*{(1-y+3*y^2/4)*[L_el-f_c+L_i <<
492 // used in case of DCS with LPM above (if all <<
493 // absent i.e. their value = 1). <<
494 // Since the Thomas-Fermi model of the atom is <<
495 // complete screening is used here at low Z(<5 <<
496 // computed by using the Dirac-Fock model of t <<
497 // NOTE: that the Ter-Mikaelian suppression is <<
498 // 1/F factor but it is included in the caller <<
499 // HERE, ds/dk(Z,k)*[F*k/C] is computed exactl <<
500 G4double <<
501 G4eBremsstrahlungRelModel::ComputeDXSectionPer <<
502 { <<
503 G4double dxsec = 0.0; <<
504 if (gammaEnergy < 0.) { <<
505 return dxsec; <<
506 } <<
507 const G4double y = gammaEnergy/fPrim <<
508 const G4double onemy = 1.-y; <<
509 const G4double dum0 = onemy+0.75*y*y; <<
510 const ElementData* elDat = (*fElementData)[f <<
511 // use complete screening and L_el, L_inel f <<
512 if (fCurrentIZ < 5 || fIsUseCompleteScreenin <<
513 dxsec = dum0*elDat->fZFactor1; <<
514 dxsec += onemy*elDat->fZFactor2; <<
515 if (fIsScatOffElectron) { <<
516 fSumTerm = dxsec; <<
517 fNucTerm = dum0*elDat->fZFactor11+onemy/ <<
518 } <<
519 } else { <<
520 // use Tsai's analytical approx. (Tsai Eqs <<
521 // numerical screening functions computed <<
522 const G4double invZ = 1./(G4double)fCur <<
523 const G4double Fz = elDat->fFz; <<
524 const G4double logZ = elDat->fLogZ; <<
525 const G4double dum1 = y/(fPrimaryTotalE <<
526 const G4double gamma = dum1*elDat->fGamm <<
527 const G4double epsilon = dum1*elDat->fEpsi <<
528 // evaluate the screening functions <<
529 G4double phi1, phi1m2, psi1, psi1m2; <<
530 ComputeScreeningFunctions(phi1, phi1m2, ps <<
531 dxsec = dum0*((0.25*phi1-Fz) + (0.25*psi1 <<
532 dxsec += 0.125*onemy*(phi1m2 + psi1m2*invZ <<
533 if (fIsScatOffElectron) { <<
534 fSumTerm = dxsec; <<
535 fNucTerm = dum0*(0.25*phi1-Fz) + 0.125*o <<
536 } 268 }
>> 269 e0 += delta;
537 } 270 }
538 return std::max(dxsec,0.0); << 271
>> 272 loss *= delta*totalEnergy;
>> 273
>> 274 return loss;
539 } 275 }
540 276
541 // Coherent and incoherent screening function << 277 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
542 // Eqs.[3.38-3.41]). Tsai's analytical approxi << 278
543 // functions computed by using the Thomas-Ferm << 279 G4double G4eBremsstrahlungRelModel::ComputeCrossSectionPerAtom(
544 // ximation to the numerical TF screening func << 280 const G4ParticleDefinition* p,
545 // screening functions can be expressed in a ' << 281 G4double kineticEnergy,
546 // pendent variable (see Tsai Eqs. Eqs. [3.30 << 282 G4double Z, G4double,
547 void G4eBremsstrahlungRelModel::ComputeScreeni << 283 G4double cutEnergy,
548 << 284 G4double maxEnergy)
549 << 285 {
550 << 286 if(!particle) { SetParticle(p); }
551 << 287 if(kineticEnergy < LowEnergyLimit()) { return 0.0; }
552 << 288 G4double cut = std::min(cutEnergy, kineticEnergy);
553 { << 289 G4double tmax = std::min(maxEnergy, kineticEnergy);
554 const G4double gam2 = gam*gam; << 290
555 phi1 = 16.863-2.0*G4Log(1.0+0.311877*gam2) << 291 if(cut >= tmax) { return 0.0; }
556 +1.6*G4Exp(-1.5*gam); << 292
557 phi1m2 = 2.0/(3.0+19.5*gam+18.0*gam2); // << 293 SetCurrentElement(Z);
558 const G4double eps2 = eps*eps; << 294
559 psi1 = 24.34-2.0*G4Log(1.0+13.111641*eps2) << 295 G4double cross = ComputeXSectionPerAtom(cut);
560 +1.2*G4Exp(-29.2*eps); << 296
561 psi1m2 = 2.0/(3.0+120.0*eps+1200.0*eps2); // << 297 // allow partial integration
562 } << 298 if(tmax < kinEnergy) { cross -= ComputeXSectionPerAtom(tmax); }
563 << 299
564 void << 300 cross *= Z*Z*bremFactor;
565 G4eBremsstrahlungRelModel::SampleSecondaries(s << 301
566 c << 302 return cross;
567 c <<
568 G <<
569 G <<
570 { <<
571 const G4double kineticEnergy = dp->GetKin <<
572 if (kineticEnergy < LowEnergyLimit()) { <<
573 return; <<
574 } <<
575 // min, max kinetic energy limits <<
576 const G4double tmin = std::min(cutEnergy, ki <<
577 const G4double tmax = std::min(maxEnergy, ki <<
578 if (tmin >= tmax) { <<
579 return; <<
580 } <<
581 // <<
582 SetupForMaterial(fPrimaryParticle, couple->G <<
583 const G4Element* elm = SelectTargetAtom(coup <<
584 dp-> <<
585 // <<
586 fCurrentIZ = elm->GetZasInt(); <<
587 const ElementData* elDat = (*fElementData)[f <<
588 const G4double funcMax = elDat->fZFactor1+el <<
589 // get the random engine <<
590 G4double rndm[2]; <<
591 CLHEP::HepRandomEngine* rndmEngine = G4Rando <<
592 // min max of the transformed variable: x(k) <<
593 const G4double xmin = G4Log(tmin*tmin+fDen <<
594 const G4double xrange = G4Log(tmax*tmax+fDen <<
595 G4double gammaEnergy, funcVal; <<
596 do { <<
597 rndmEngine->flatArray(2, rndm); <<
598 gammaEnergy = std::sqrt(std::max(G4Exp(xmi <<
599 funcVal = fIsLPMActive <<
600 ? ComputeRelDXSectionPerAtom( <<
601 : ComputeDXSectionPerAtom(gam <<
602 // cross-check of proper function maximum <<
603 // if (funcVal > funcMax) { <<
604 // G4cout << "### G4eBremsstrahlungRelMod <<
605 // << funcVal << " > " << funcMax <<
606 // << " Egamma(MeV)= " << gammaEnergy <<
607 // << " Ee(MeV)= " << kineticEnergy <<
608 // << " " << GetName() <<
609 // << G4endl; <<
610 // } <<
611 // Loop checking, 03-Aug-2015, Vladimir Iv <<
612 } while (funcVal < funcMax*rndm[1]); <<
613 // <<
614 // scattering off nucleus or off e- by tripl <<
615 if (fIsScatOffElectron && rndmEngine->flat() <<
616 GetTripletModel()->SampleSecondaries(vdp, <<
617 return; <<
618 } <<
619 // <<
620 // angles of the emitted gamma. ( Z - axis a <<
621 // use general interface <<
622 G4ThreeVector gamDir = <<
623 GetAngularDistribution()->SampleDirection( <<
624 <<
625 // create G4DynamicParticle object for the G <<
626 auto gamma = new G4DynamicParticle(fGammaPar <<
627 vdp->push_back(gamma); <<
628 // compute post-interaction kinematics of pr <<
629 // energy-momentum conservation <<
630 const G4double totMomentum = std::sqrt(kinet <<
631 fPrimaryTotalEn <<
632 G4ThreeVector dir = <<
633 (totMomentum*dp->GetMomentumDirec <<
634 const G4double finalE = kineticEnergy-gamm <<
635 // if secondary gamma energy is higher than <<
636 // then stop tracking the primary particle a <<
637 // instead of the primary one <<
638 if (gammaEnergy > SecondaryThreshold()) { <<
639 fParticleChange->ProposeTrackStatus(fStopA <<
640 fParticleChange->SetProposedKineticEnergy( <<
641 auto el = new G4DynamicParticle( <<
642 const_cast<G4ParticleDefinition* <<
643 vdp->push_back(el); <<
644 } else { // continue tracking the primary e- <<
645 fParticleChange->SetProposedMomentumDirect <<
646 fParticleChange->SetProposedKineticEnergy( <<
647 } <<
648 } 303 }
>> 304
>> 305 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 306
649 307
650 void G4eBremsstrahlungRelModel::InitialiseElem << 308 G4double G4eBremsstrahlungRelModel::ComputeXSectionPerAtom(G4double cut)
651 { 309 {
652 // create for all elements that are in the d << 310 G4double cross = 0.0;
653 auto elemTable = G4Element::GetElementTable( << 311
654 for (auto const & elem : *elemTable) { << 312 // number of intervals and integration step
655 const G4double zet = elem->GetZ(); << 313 G4double vcut = G4Log(cut/totalEnergy);
656 const G4int izet = std::min(elem->GetZasIn << 314 G4double vmax = G4Log(kinEnergy/totalEnergy);
657 if (nullptr == (*fElementData)[izet]) { << 315 G4int n = (G4int)(0.45*(vmax - vcut)) + 4;
658 auto elemData = new ElementData(); << 316 // n=1; // integration test
659 const G4double fc = elem->GetfCoulomb(); << 317 G4double delta = (vmax - vcut)/G4double(n);
660 G4double Fel = 1.; << 318
661 G4double Finel = 1.; << 319 G4double e0 = vcut;
662 elemData->fLogZ = G4Log(zet); << 320 G4double xs;
663 elemData->fFz = elemData->fLogZ/3.+f << 321
664 if (izet < 5) { << 322 // integration
665 Fel = gFelLowZet[izet]; << 323 for(G4int l=0; l<n; l++) {
666 Finel = gFinelLowZet[izet]; << 324
>> 325 for(G4int i=0; i<8; i++) {
>> 326
>> 327 G4double eg = G4Exp(e0 + xgi[i]*delta)*totalEnergy;
>> 328
>> 329 if(totalEnergy > energyThresholdLPM) {
>> 330 xs = ComputeRelDXSectionPerAtom(eg);
667 } else { 331 } else {
668 Fel = G4Log(184.15) - elemData->f << 332 xs = ComputeDXSectionPerAtom(eg);
669 Finel = G4Log(1194) - 2.*elemData->f <<
670 } 333 }
671 const G4double z13 = G4Pow::GetInstance( << 334 cross += wgi[i]*xs/(1.0 + densityCorr/(eg*eg));
672 const G4double z23 = z13*z13; <<
673 elemData->fZFactor1 = (Fel-fc)+Fine <<
674 elemData->fZFactor11 = (Fel-fc); // <<
675 elemData->fZFactor2 = (1.+1./zet)/1 <<
676 elemData->fVarS1 = z23/(184.15*1 <<
677 elemData->fILVarS1Cond = 1./(G4Log(std <<
678 elemData->fILVarS1 = 1./G4Log(elem <<
679 elemData->fGammaFactor = 100.0*electro <<
680 elemData->fEpsilonFactor = 100.0*electro <<
681 (*fElementData)[izet] = elemData; <<
682 } 335 }
>> 336 e0 += delta;
683 } 337 }
>> 338
>> 339 cross *= delta;
>> 340
>> 341 return cross;
684 } 342 }
685 343
686 void G4eBremsstrahlungRelModel::ComputeLPMfunc << 344 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
687 << 345
688 << 346 void G4eBremsstrahlungRelModel::CalcLPMFunctions(G4double k)
689 << 347 {
690 { << 348 // *** calculate lpm variable s & sprime ***
691 static const G4double sqrt2 = std::sqrt(2.); << 349 // Klein eqs. (78) & (79)
692 const G4double redegamma = egamma/fPrimar << 350 G4double sprime = sqrt(0.125*k*lpmEnergy/(totalEnergy*(totalEnergy-k)));
693 const G4double varSprime = std::sqrt(0.12 << 351
694 ((1.0-redegamm << 352 G4double s1 = preS1*z23;
695 const ElementData* elDat = (*fElementData << 353 G4double logS1 = 2./3.*lnZ-2.*facFel;
696 const G4double varS1 = elDat->fVarS1; << 354 G4double logTS1 = logTwo+logS1;
697 const G4double condition = sqrt2*varS1; << 355
698 G4double funcXiSprime = 2.0; << 356 xiLPM = 2.;
699 if (varSprime > 1.0) { << 357
700 funcXiSprime = 1.0; << 358 if (sprime>1)
701 } else if (varSprime > condition) { << 359 xiLPM = 1.;
702 const G4double ilVarS1Cond = elDat->fILVar << 360 else if (sprime>sqrt(2.)*s1) {
703 const G4double funcHSprime = G4Log(varSpri << 361 G4double h = G4Log(sprime)/logTS1;
704 funcXiSprime = 1.0 + funcHSprime - 0.08*(1 << 362 xiLPM = 1+h-0.08*(1-h)*(1-sqr(1-h))/logTS1;
705 *(2.0-fu <<
706 } <<
707 const G4double varS = varSprime/std::sqrt <<
708 // - include dielectric suppression effect i <<
709 const G4double varShat = varS*(1.0+fDensityC <<
710 funcXiS = 2.0; <<
711 if (varShat > 1.0) { <<
712 funcXiS = 1.0; <<
713 } else if (varShat > varS1) { <<
714 funcXiS = 1.0+G4Log(varShat)*elDat->fILVar <<
715 } 363 }
716 GetLPMFunctions(funcGS, funcPhiS, varShat); << 364
717 //ComputeLPMGsPhis(funcGS, funcPhiS, varShat << 365 G4double s0 = sprime/sqrt(xiLPM);
718 // << 366
719 //MAKE SURE SUPPRESSION IS SMALLER THAN 1: d << 367 // *** merging with density effect*** should be only necessary in region
720 if (funcXiS*funcPhiS > 1. || varShat > 0.57) << 368 // "close to" kp, e.g. k<100*kp using Ter-Mikaelian eq. (20.9)
721 funcXiS=1./funcPhiS; << 369 G4double k2 = k*k;
>> 370 s0 *= (1 + (densityCorr/k2) );
>> 371
>> 372 // recalculate Xi using modified s above
>> 373 // Klein eq. (75)
>> 374 xiLPM = 1.;
>> 375 if (s0<=s1) xiLPM = 2.;
>> 376 else if ( (s1<s0) && (s0<=1) ) { xiLPM = 1. + G4Log(s0)/logS1; }
>> 377
>> 378
>> 379 // *** calculate supression functions phi and G ***
>> 380 // Klein eqs. (77)
>> 381 G4double s2=s0*s0;
>> 382 G4double s3=s0*s2;
>> 383 G4double s4=s2*s2;
>> 384
>> 385 if (s0<0.1) {
>> 386 // high suppression limit
>> 387 phiLPM = 6.*s0 - 18.84955592153876*s2 + 39.47841760435743*s3
>> 388 - 57.69873135166053*s4;
>> 389 gLPM = 37.69911184307752*s2 - 236.8705056261446*s3 + 807.7822389*s4;
>> 390 }
>> 391 else if (s0<1.9516) {
>> 392 // intermediate suppression
>> 393 // using eq.77 approxim. valid s<2.
>> 394 phiLPM = 1.-G4Exp(-6.*s0*(1.+(3.-pi)*s0)
>> 395 +s3/(0.623+0.795*s0+0.658*s2));
>> 396 if (s0<0.415827397755) {
>> 397 // using eq.77 approxim. valid 0.07<s<2
>> 398 G4double psiLPM = 1-G4Exp(-4*s0-8*s2/(1+3.936*s0+4.97*s2-0.05*s3+7.50*s4));
>> 399 gLPM = 3*psiLPM-2*phiLPM;
>> 400 }
>> 401 else {
>> 402 // using alternative parametrisiation
>> 403 G4double pre = -0.16072300849123999 + s0*3.7550300067531581 + s2*-1.7981383069010097
>> 404 + s3*0.67282686077812381 + s4*-0.1207722909879257;
>> 405 gLPM = tanh(pre);
>> 406 }
>> 407 }
>> 408 else {
>> 409 // low suppression limit valid s>2.
>> 410 phiLPM = 1. - 0.0119048/s4;
>> 411 gLPM = 1. - 0.0230655/s4;
722 } 412 }
>> 413
>> 414 // *** make sure suppression is smaller than 1 ***
>> 415 // *** caused by Migdal approximation in xi ***
>> 416 if (xiLPM*phiLPM>1. || s0>0.57) { xiLPM=1./phiLPM; }
723 } 417 }
724 418
725 void G4eBremsstrahlungRelModel::ComputeLPMGsPh << 419 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
726 << 420
727 << 421
>> 422 G4double G4eBremsstrahlungRelModel::ComputeRelDXSectionPerAtom(G4double gammaEnergy)
>> 423 // Ultra relativistic model
>> 424 // only valid for very high energies, but includes LPM suppression
>> 425 // * complete screening
728 { 426 {
729 if (varShat < 0.01) { << 427 if(gammaEnergy < 0.0) { return 0.0; }
730 funcPhiS = 6.0*varShat*(1.0-CLHEP::pi*varS << 428
731 funcGS = 12.0*varShat-2.0*funcPhiS; << 429 G4double y = gammaEnergy/totalEnergy;
732 } else { << 430 G4double y2 = y*y*.25;
733 const G4double varShat2 = varShat*varShat; << 431 G4double yone2 = (1.-y+2.*y2);
734 const G4double varShat3 = varShat*varShat2 << 432
735 const G4double varShat4 = varShat2*varShat << 433 // ** form factors complete screening case **
736 // use Stanev approximation: for \psi(s) a << 434
737 if (varShat < 0.415827) { << 435 // ** calc LPM functions -- include ter-mikaelian merging with density effect **
738 funcPhiS = 1.0-G4Exp(-6.0*varShat*(1.0+v << 436 // G4double xiLPM, gLPM, phiLPM; // to be made member variables !!!
739 + varShat3/(0.623+0.796*varSha << 437 CalcLPMFunctions(gammaEnergy);
740 // 1-\exp \left\{-4s-\frac{8s^2}{1+3.936 << 438
741 const G4double funcPsiS = 1.0 - G4Exp(-4 << 439 G4double mainLPM = xiLPM*(y2 * gLPM + yone2*phiLPM) * ( (Fel-fCoulomb) + Finel/currentZ );
742 - 8.0*varShat2/ << 440 G4double secondTerm = (1.-y)/12.*(1.+1./currentZ);
743 - 0.05*varShat3 << 441
744 // G(s) = 3 \psi(s) - 2 \phi(s) << 442 G4double cross = mainLPM+secondTerm;
745 funcGS = 3.0*funcPsiS - 2.0*funcPhiS; << 443 return cross;
746 } else if (varShat<1.55) { <<
747 funcPhiS = 1.0-G4Exp(-6.0*varShat*(1.0+v <<
748 + varShat3/(0.623+0.796*varSha <<
749 const G4double dum0 = -0.160723 <<
750 -1.798138*varShat <<
751 -0.120772*varShat <<
752 funcGS = std::tanh(dum0); <<
753 } else { <<
754 funcPhiS = 1.0-0.011905/varShat4; <<
755 if (varShat<1.9156) { <<
756 const G4double dum0 = -0.160723 <<
757 -1.798138*varSha <<
758 -0.120772*varSha <<
759 funcGS = std::tanh(dum0); <<
760 } else { <<
761 funcGS = 1.0-0.023065/varShat4; <<
762 } <<
763 } <<
764 } <<
765 } 444 }
766 445
767 // s goes up to 2 with ds = 0.01 to be the def << 446 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
768 void G4eBremsstrahlungRelModel::InitLPMFunctio << 447
>> 448 G4double G4eBremsstrahlungRelModel::ComputeDXSectionPerAtom(G4double gammaEnergy)
>> 449 // Relativistic model
>> 450 // only valid for high energies (and if LPM suppression does not play a role)
>> 451 // * screening according to thomas-fermi-Model (only valid for Z>5)
>> 452 // * no LPM effect
769 { 453 {
770 if (!fLPMFuncs->fIsInitialized) { << 454
771 const G4int num = fLPMFuncs->fSLimit*fLPMF << 455 if(gammaEnergy < 0.0) { return 0.0; }
772 fLPMFuncs->fLPMFuncG.resize(num); << 456
773 fLPMFuncs->fLPMFuncPhi.resize(num); << 457 G4double y = gammaEnergy/totalEnergy;
774 for (G4int i = 0; i < num; ++i) { << 458
775 const G4double sval=i/fLPMFuncs->fISDelt << 459 G4double main=0.,secondTerm=0.;
776 ComputeLPMGsPhis(fLPMFuncs->fLPMFuncG[i] << 460
777 } << 461 if (use_completescreening|| currentZ<5) {
778 fLPMFuncs->fIsInitialized = true; << 462 // ** form factors complete screening case **
>> 463 main = (3./4.*y*y - y + 1.) * ( (Fel-fCoulomb) + Finel/currentZ );
>> 464 secondTerm = (1.-y)/12.*(1.+1./currentZ);
779 } 465 }
>> 466 else {
>> 467 // ** intermediate screening using Thomas-Fermi FF from Tsai only valid for Z>=5**
>> 468 G4double dd=100.*electron_mass_c2*y/(totalEnergy-gammaEnergy);
>> 469 G4double gg=dd/z13;
>> 470 G4double eps=dd/z23;
>> 471 G4double phi1=Phi1(gg,currentZ), phi1m2=Phi1M2(gg,currentZ);
>> 472 G4double psi1=Psi1(eps,currentZ), psi1m2=Psi1M2(eps,currentZ);
>> 473
>> 474 main = (3./4.*y*y - y + 1.) * ( (0.25*phi1-1./3.*lnZ-fCoulomb) + (0.25*psi1-2./3.*lnZ)/currentZ );
>> 475 secondTerm = (1.-y)/8.*(phi1m2+psi1m2/currentZ);
>> 476 }
>> 477 G4double cross = main+secondTerm;
>> 478 return cross;
780 } 479 }
781 480
782 void G4eBremsstrahlungRelModel::GetLPMFunction << 481 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
783 << 482
784 << 483 void G4eBremsstrahlungRelModel::SampleSecondaries(
785 { << 484 std::vector<G4DynamicParticle*>* vdp,
786 if (sval < fLPMFuncs->fSLimit) { << 485 const G4MaterialCutsCouple* couple,
787 G4double val = sval*fLPMFuncs->fISDelt << 486 const G4DynamicParticle* dp,
788 const G4int ilow = (G4int)val; << 487 G4double cutEnergy,
789 val -= ilow; << 488 G4double maxEnergy)
790 lpmGs = (fLPMFuncs->fLPMFuncG[ilow+1]-fL << 489 {
791 + fLPMFuncs->fLPMFuncG[ilow]; << 490 G4double kineticEnergy = dp->GetKineticEnergy();
792 lpmPhis = (fLPMFuncs->fLPMFuncPhi[ilow+1]- << 491 if(kineticEnergy < LowEnergyLimit()) { return; }
793 + fLPMFuncs->fLPMFuncPhi[ilow]; << 492 G4double cut = std::min(cutEnergy, kineticEnergy);
>> 493 G4double emax = std::min(maxEnergy, kineticEnergy);
>> 494 if(cut >= emax) { return; }
>> 495
>> 496 SetupForMaterial(particle, couple->GetMaterial(), kineticEnergy);
>> 497
>> 498 const G4Element* elm =
>> 499 SelectRandomAtom(couple,particle,kineticEnergy,cut,emax);
>> 500 SetCurrentElement(elm->GetZ());
>> 501
>> 502 kinEnergy = kineticEnergy;
>> 503 totalEnergy = kineticEnergy + particleMass;
>> 504 densityCorr = densityFactor*totalEnergy*totalEnergy;
>> 505
>> 506 //G4double fmax= fMax;
>> 507 G4bool highe = true;
>> 508 if(totalEnergy < energyThresholdLPM) { highe = false; }
>> 509
>> 510 G4double xmin = G4Log(cut*cut + densityCorr);
>> 511 G4double xmax = G4Log(emax*emax + densityCorr);
>> 512 G4double gammaEnergy, f, x;
>> 513
>> 514 do {
>> 515 x = G4Exp(xmin + G4UniformRand()*(xmax - xmin)) - densityCorr;
>> 516 if(x < 0.0) { x = 0.0; }
>> 517 gammaEnergy = sqrt(x);
>> 518 if(highe) { f = ComputeRelDXSectionPerAtom(gammaEnergy); }
>> 519 else { f = ComputeDXSectionPerAtom(gammaEnergy); }
>> 520
>> 521 if ( f > fMax ) {
>> 522 G4cout << "### G4eBremsstrahlungRelModel Warning: Majoranta exceeded! "
>> 523 << f << " > " << fMax
>> 524 << " Egamma(MeV)= " << gammaEnergy
>> 525 << " Ee(MeV)= " << kineticEnergy
>> 526 << " " << GetName()
>> 527 << G4endl;
>> 528 }
>> 529
>> 530 } while (f < fMax*G4UniformRand());
>> 531
>> 532 //
>> 533 // angles of the emitted gamma. ( Z - axis along the parent particle)
>> 534 // use general interface
>> 535 //
>> 536
>> 537 G4ThreeVector gammaDirection =
>> 538 GetAngularDistribution()->SampleDirection(dp, totalEnergy-gammaEnergy,
>> 539 G4lrint(currentZ),
>> 540 couple->GetMaterial());
>> 541
>> 542 // create G4DynamicParticle object for the Gamma
>> 543 G4DynamicParticle* gamma = new G4DynamicParticle(theGamma,gammaDirection,
>> 544 gammaEnergy);
>> 545 vdp->push_back(gamma);
>> 546
>> 547 G4double totMomentum = sqrt(kineticEnergy*(totalEnergy + electron_mass_c2));
>> 548 G4ThreeVector direction = (totMomentum*dp->GetMomentumDirection()
>> 549 - gammaEnergy*gammaDirection).unit();
>> 550
>> 551 // energy of primary
>> 552 G4double finalE = kineticEnergy - gammaEnergy;
>> 553
>> 554 // stop tracking and create new secondary instead of primary
>> 555 if(gammaEnergy > SecondaryThreshold()) {
>> 556 fParticleChange->ProposeTrackStatus(fStopAndKill);
>> 557 fParticleChange->SetProposedKineticEnergy(0.0);
>> 558 G4DynamicParticle* el =
>> 559 new G4DynamicParticle(const_cast<G4ParticleDefinition*>(particle),
>> 560 direction, finalE);
>> 561 vdp->push_back(el);
>> 562
>> 563 // continue tracking
794 } else { 564 } else {
795 G4double ss = sval*sval; << 565 fParticleChange->SetProposedMomentumDirection(direction);
796 ss *= ss; << 566 fParticleChange->SetProposedKineticEnergy(finalE);
797 lpmPhis = 1.0-0.01190476/ss; <<
798 lpmGs = 1.0-0.0230655/ss; <<
799 } 567 }
800 } 568 }
>> 569
>> 570 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
>> 571
801 572
802 573