1 | // |
---|
2 | // ******************************************************************** |
---|
3 | // * License and Disclaimer * |
---|
4 | // * * |
---|
5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
7 | // * conditions of the Geant4 Software License, included in the file * |
---|
8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
9 | // * include a list of copyright holders. * |
---|
10 | // * * |
---|
11 | // * Neither the authors of this software system, nor their employing * |
---|
12 | // * institutes,nor the agencies providing financial support for this * |
---|
13 | // * work make any representation or warranty, express or implied, * |
---|
14 | // * regarding this software system or assume any liability for its * |
---|
15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
16 | // * for the full disclaimer and the limitation of liability. * |
---|
17 | // * * |
---|
18 | // * This code implementation is the result of the scientific and * |
---|
19 | // * technical work of the GEANT4 collaboration. * |
---|
20 | // * By using, copying, modifying or distributing the software (or * |
---|
21 | // * any work based on the software) you agree to acknowledge its * |
---|
22 | // * use in resulting scientific publications, and indicate your * |
---|
23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
24 | // ******************************************************************** |
---|
25 | // |
---|
26 | // -------------------------------------------------------------------- |
---|
27 | // |
---|
28 | // |
---|
29 | // |
---|
30 | // -------------------------------------------------------------- |
---|
31 | // |
---|
32 | // Author: L.Pandola |
---|
33 | // History: |
---|
34 | // -------- |
---|
35 | // 02 Dec 2002 L.Pandola 1st implementation |
---|
36 | // 12 Feb 2003 MG Pia Migration to "cuts per region" |
---|
37 | // 10 Mar 2003 V.Ivanchenko Remove CutPerMaterial warning |
---|
38 | // 13 Mar 2003 L.Pandola Code "cleaned" |
---|
39 | // 25 Mar 2003 L.Pandola Changed the name of the database file to read |
---|
40 | // 24 Apr 2003 V.Ivanchenko Cut per region mfpt |
---|
41 | // 17 Mar 2004 L.Pandola Removed unnecessary calls to std::pow(a,b) |
---|
42 | // -------------------------------------------------------------- |
---|
43 | |
---|
44 | #include "G4PenelopeGammaConversion.hh" |
---|
45 | |
---|
46 | #include "Randomize.hh" |
---|
47 | #include "G4ParticleDefinition.hh" |
---|
48 | #include "G4Track.hh" |
---|
49 | #include "G4Step.hh" |
---|
50 | #include "G4ForceCondition.hh" |
---|
51 | #include "G4Gamma.hh" |
---|
52 | #include "G4Electron.hh" |
---|
53 | #include "G4DynamicParticle.hh" |
---|
54 | #include "G4VParticleChange.hh" |
---|
55 | #include "G4ThreeVector.hh" |
---|
56 | #include "G4Positron.hh" |
---|
57 | #include "G4IonisParamElm.hh" |
---|
58 | #include "G4Material.hh" |
---|
59 | #include "G4VCrossSectionHandler.hh" |
---|
60 | #include "G4CrossSectionHandler.hh" |
---|
61 | #include "G4VEMDataSet.hh" |
---|
62 | #include "G4VDataSetAlgorithm.hh" |
---|
63 | #include "G4LogLogInterpolation.hh" |
---|
64 | #include "G4VRangeTest.hh" |
---|
65 | #include "G4RangeTest.hh" |
---|
66 | #include "G4MaterialCutsCouple.hh" |
---|
67 | |
---|
68 | |
---|
69 | G4PenelopeGammaConversion::G4PenelopeGammaConversion(const G4String& processName) |
---|
70 | : G4VDiscreteProcess(processName), |
---|
71 | lowEnergyLimit(1.022000*MeV), |
---|
72 | highEnergyLimit(100*GeV), |
---|
73 | intrinsicLowEnergyLimit(1.022000*MeV), |
---|
74 | intrinsicHighEnergyLimit(100*GeV), |
---|
75 | smallEnergy(1.1*MeV) |
---|
76 | |
---|
77 | { |
---|
78 | if (lowEnergyLimit < intrinsicLowEnergyLimit || |
---|
79 | highEnergyLimit > intrinsicHighEnergyLimit) |
---|
80 | { |
---|
81 | G4Exception("G4PenelopeGammaConversion::G4PenelopeGammaConversion - energy limit outside intrinsic process validity range"); |
---|
82 | } |
---|
83 | |
---|
84 | // The following pointer is owned by G4DataHandler |
---|
85 | crossSectionHandler = new G4CrossSectionHandler(); |
---|
86 | // Log log interpolation (default) |
---|
87 | crossSectionHandler->Initialise(0,1.0220*MeV,100.*GeV,400); |
---|
88 | meanFreePathTable = 0; |
---|
89 | rangeTest = new G4RangeTest; |
---|
90 | |
---|
91 | if (verboseLevel > 0) |
---|
92 | { |
---|
93 | G4cout << GetProcessName() << " is created " << G4endl |
---|
94 | << "Energy range: " |
---|
95 | << lowEnergyLimit / MeV << " MeV - " |
---|
96 | << highEnergyLimit / GeV << " GeV" |
---|
97 | << G4endl; |
---|
98 | } |
---|
99 | |
---|
100 | G4cout << G4endl; |
---|
101 | G4cout << "*******************************************************************************" << G4endl; |
---|
102 | G4cout << "*******************************************************************************" << G4endl; |
---|
103 | G4cout << " The class G4PenelopeGammaConversion is NOT SUPPORTED ANYMORE. " << G4endl; |
---|
104 | G4cout << " It will be REMOVED with the next major release of Geant4. " << G4endl; |
---|
105 | G4cout << " Please consult: https://twiki.cern.ch/twiki/bin/view/Geant4/LoweProcesses" << G4endl; |
---|
106 | G4cout << "*******************************************************************************" << G4endl; |
---|
107 | G4cout << "*******************************************************************************" << G4endl; |
---|
108 | G4cout << G4endl; |
---|
109 | } |
---|
110 | |
---|
111 | G4PenelopeGammaConversion::~G4PenelopeGammaConversion() |
---|
112 | { |
---|
113 | delete meanFreePathTable; |
---|
114 | delete crossSectionHandler; |
---|
115 | delete rangeTest; |
---|
116 | } |
---|
117 | |
---|
118 | void G4PenelopeGammaConversion::BuildPhysicsTable(const G4ParticleDefinition& ) |
---|
119 | { |
---|
120 | |
---|
121 | crossSectionHandler->Clear(); |
---|
122 | G4String crossSectionFile = "penelope/pp-cs-pen-"; |
---|
123 | crossSectionHandler->LoadData(crossSectionFile); |
---|
124 | delete meanFreePathTable; |
---|
125 | meanFreePathTable = crossSectionHandler->BuildMeanFreePathForMaterials(); |
---|
126 | } |
---|
127 | |
---|
128 | G4VParticleChange* G4PenelopeGammaConversion::PostStepDoIt(const G4Track& aTrack, |
---|
129 | const G4Step& aStep) |
---|
130 | { |
---|
131 | aParticleChange.Initialize(aTrack); |
---|
132 | |
---|
133 | const G4MaterialCutsCouple* couple = aTrack.GetMaterialCutsCouple(); |
---|
134 | |
---|
135 | const G4DynamicParticle* incidentPhoton = aTrack.GetDynamicParticle(); |
---|
136 | G4double photonEnergy = incidentPhoton->GetKineticEnergy(); |
---|
137 | G4ParticleMomentum photonDirection = incidentPhoton->GetMomentumDirection(); |
---|
138 | |
---|
139 | G4double eps ; |
---|
140 | G4double eki = electron_mass_c2 / photonEnergy ; |
---|
141 | |
---|
142 | // Do it fast if photon energy < 1.1 MeV |
---|
143 | if (photonEnergy < smallEnergy ) |
---|
144 | { |
---|
145 | eps = eki + (1-2*eki) * G4UniformRand(); |
---|
146 | } |
---|
147 | else |
---|
148 | { |
---|
149 | // Select randomly one element in the current material |
---|
150 | const G4Element* element = crossSectionHandler->SelectRandomElement(couple,photonEnergy); |
---|
151 | |
---|
152 | if (element == 0) |
---|
153 | { |
---|
154 | G4cout << "G4PenelopeGammaConversion::PostStepDoIt - element = 0" << G4endl; |
---|
155 | } |
---|
156 | G4IonisParamElm* ionisation = element->GetIonisation(); |
---|
157 | if (ionisation == 0) |
---|
158 | { |
---|
159 | G4cout << "G4PenelopeGammaConversion::PostStepDoIt - ionisation = 0" << G4endl; |
---|
160 | } |
---|
161 | |
---|
162 | //Low energy and Coulomb corrections |
---|
163 | G4double Z=ionisation->GetZ(); |
---|
164 | G4double ZAlpha = Z*fine_structure_const; |
---|
165 | G4double ScreenRadius = GetScreeningRadius(Z); |
---|
166 | G4double funct1=0,g0=0; |
---|
167 | G4double g1min=0,g2min=0; |
---|
168 | funct1 = 4.0*std::log(ScreenRadius); |
---|
169 | g0 = funct1-4*CoulombCorrection(ZAlpha)+LowEnergyCorrection(ZAlpha,eki); |
---|
170 | G4double bmin = 2*eki*ScreenRadius; |
---|
171 | g1min=g0+ScreenFunction(bmin,1); |
---|
172 | g2min=g0+ScreenFunction(bmin,2); |
---|
173 | G4double xr,a1,p1; |
---|
174 | xr=0.5-eki; |
---|
175 | a1=(2.0/3.0)*g1min*xr*xr; |
---|
176 | p1=a1/(a1+g2min); |
---|
177 | |
---|
178 | //Random sampling of eps |
---|
179 | G4double rand1,rand2,rand3,b; |
---|
180 | G4double g1; |
---|
181 | |
---|
182 | do{ |
---|
183 | rand1 = G4UniformRand(); |
---|
184 | if (rand1 < p1) { |
---|
185 | rand2 = 2.0*G4UniformRand()-1.0; |
---|
186 | if (rand2 < 0) { |
---|
187 | eps = 0.5 - xr*std::pow(std::abs(rand2),(1./3.)); |
---|
188 | } |
---|
189 | else |
---|
190 | { |
---|
191 | eps = 0.5 + xr*std::pow(rand2,(1./3.)); |
---|
192 | } |
---|
193 | b = (eki*ScreenRadius)/(2*eps*(1.0-eps)); |
---|
194 | g1 = g0+ScreenFunction(b,1); |
---|
195 | if (g1 < 0) g1=0; |
---|
196 | rand3 = G4UniformRand()*g1min; |
---|
197 | } |
---|
198 | else |
---|
199 | { |
---|
200 | eps = eki+2.0*xr*G4UniformRand(); |
---|
201 | b = (eki*ScreenRadius)/(2*eps*(1.0-eps)); |
---|
202 | g1 = g0+ScreenFunction(b,2); |
---|
203 | if (g1 < 0) g1=0; |
---|
204 | rand3 = G4UniformRand()*g2min; |
---|
205 | } |
---|
206 | } while (rand3>g1); |
---|
207 | } //End of eps sampling |
---|
208 | |
---|
209 | G4double electronTotEnergy; |
---|
210 | G4double positronTotEnergy; |
---|
211 | |
---|
212 | electronTotEnergy = eps*photonEnergy; |
---|
213 | positronTotEnergy = (1.0-eps)*photonEnergy; |
---|
214 | |
---|
215 | // Scattered electron (positron) angles. ( Z - axis along the parent photon) |
---|
216 | |
---|
217 | //electron kinematics |
---|
218 | G4double costheta_el,costheta_po; |
---|
219 | G4double phi_el,phi_po; |
---|
220 | G4double electronKineEnergy = std::max(0.,electronTotEnergy - electron_mass_c2) ; |
---|
221 | costheta_el = G4UniformRand()*2.0-1.0; |
---|
222 | G4double kk = std::sqrt(electronKineEnergy*(electronKineEnergy+2.*electron_mass_c2)); |
---|
223 | costheta_el = (costheta_el*electronTotEnergy+kk)/(electronTotEnergy+costheta_el*kk); |
---|
224 | phi_el = twopi * G4UniformRand() ; |
---|
225 | G4double dirX_el = std::sqrt(1.-costheta_el*costheta_el) * std::cos(phi_el); |
---|
226 | G4double dirY_el = std::sqrt(1.-costheta_el*costheta_el) * std::sin(phi_el); |
---|
227 | G4double dirZ_el = costheta_el; |
---|
228 | |
---|
229 | //positron kinematics |
---|
230 | G4double positronKineEnergy = std::max(0.,positronTotEnergy - electron_mass_c2) ; |
---|
231 | costheta_po = G4UniformRand()*2.0-1.0; |
---|
232 | kk = std::sqrt(positronKineEnergy*(positronKineEnergy+2.*electron_mass_c2)); |
---|
233 | costheta_po = (costheta_po*positronTotEnergy+kk)/(positronTotEnergy+costheta_po*kk); |
---|
234 | phi_po = twopi * G4UniformRand() ; |
---|
235 | G4double dirX_po = std::sqrt(1.-costheta_po*costheta_po) * std::cos(phi_po); |
---|
236 | G4double dirY_po = std::sqrt(1.-costheta_po*costheta_po) * std::sin(phi_po); |
---|
237 | G4double dirZ_po = costheta_po; |
---|
238 | |
---|
239 | // Kinematics of the created pair: |
---|
240 | // the electron and positron are assumed to have a symetric angular |
---|
241 | // distribution with respect to the Z axis along the parent photon |
---|
242 | |
---|
243 | G4double localEnergyDeposit = 0. ; |
---|
244 | |
---|
245 | aParticleChange.SetNumberOfSecondaries(2) ; |
---|
246 | |
---|
247 | |
---|
248 | // Generate the electron only if with large enough range w.r.t. cuts and safety |
---|
249 | |
---|
250 | G4double safety = aStep.GetPostStepPoint()->GetSafety(); |
---|
251 | |
---|
252 | if (rangeTest->Escape(G4Electron::Electron(),couple,electronKineEnergy,safety)) |
---|
253 | { |
---|
254 | G4ThreeVector electronDirection ( dirX_el, dirY_el, dirZ_el); |
---|
255 | electronDirection.rotateUz(photonDirection); |
---|
256 | G4DynamicParticle* particle1 = new G4DynamicParticle (G4Electron::Electron(), |
---|
257 | electronDirection, |
---|
258 | electronKineEnergy); |
---|
259 | aParticleChange.AddSecondary(particle1) ; |
---|
260 | } |
---|
261 | else |
---|
262 | { |
---|
263 | localEnergyDeposit += electronKineEnergy ; |
---|
264 | } |
---|
265 | |
---|
266 | |
---|
267 | if (! (rangeTest->Escape(G4Positron::Positron(),couple,positronKineEnergy,safety))) |
---|
268 | { |
---|
269 | localEnergyDeposit += positronKineEnergy ; |
---|
270 | positronKineEnergy = 0. ; |
---|
271 | } |
---|
272 | G4ThreeVector positronDirection(dirX_po,dirY_po,dirZ_po); |
---|
273 | positronDirection.rotateUz(photonDirection); |
---|
274 | |
---|
275 | // Create G4DynamicParticle object for the particle2 |
---|
276 | G4DynamicParticle* particle2 = new G4DynamicParticle(G4Positron::Positron(), |
---|
277 | positronDirection, positronKineEnergy); |
---|
278 | aParticleChange.AddSecondary(particle2) ; |
---|
279 | |
---|
280 | aParticleChange.ProposeLocalEnergyDeposit(localEnergyDeposit) ; |
---|
281 | |
---|
282 | // Kill the incident photon |
---|
283 | aParticleChange.ProposeMomentumDirection(0.,0.,0.) ; |
---|
284 | aParticleChange.ProposeEnergy(0.) ; |
---|
285 | aParticleChange.ProposeTrackStatus(fStopAndKill) ; |
---|
286 | |
---|
287 | // Reset NbOfInteractionLengthLeft and return aParticleChange |
---|
288 | return G4VDiscreteProcess::PostStepDoIt(aTrack,aStep); |
---|
289 | } |
---|
290 | |
---|
291 | G4bool G4PenelopeGammaConversion::IsApplicable(const G4ParticleDefinition& particle) |
---|
292 | { |
---|
293 | return ( &particle == G4Gamma::Gamma() ); |
---|
294 | } |
---|
295 | |
---|
296 | G4double G4PenelopeGammaConversion::GetMeanFreePath(const G4Track& track, |
---|
297 | G4double, // previousStepSize |
---|
298 | G4ForceCondition*) |
---|
299 | { |
---|
300 | const G4DynamicParticle* photon = track.GetDynamicParticle(); |
---|
301 | G4double energy = photon->GetKineticEnergy(); |
---|
302 | const G4MaterialCutsCouple* couple = track.GetMaterialCutsCouple(); |
---|
303 | size_t materialIndex = couple->GetIndex(); |
---|
304 | |
---|
305 | G4double meanFreePath; |
---|
306 | if (energy > highEnergyLimit) meanFreePath = meanFreePathTable->FindValue(highEnergyLimit,materialIndex); |
---|
307 | else if (energy < lowEnergyLimit) meanFreePath = DBL_MAX; |
---|
308 | else meanFreePath = meanFreePathTable->FindValue(energy,materialIndex); |
---|
309 | return meanFreePath; |
---|
310 | } |
---|
311 | |
---|
312 | G4double G4PenelopeGammaConversion::ScreenFunction(G4double b,G4int icase) |
---|
313 | { |
---|
314 | G4double bsquare=b*b; |
---|
315 | G4double a0,f1,f2,g1,g2; |
---|
316 | f1=2.0-2*std::log(1+bsquare); |
---|
317 | f2=f1-(2.0/3.0); |
---|
318 | if (b < 1.0e-10) |
---|
319 | { |
---|
320 | f1=f1-twopi*b; |
---|
321 | } |
---|
322 | else |
---|
323 | { |
---|
324 | a0 = 4*b*std::atan(1.0/b); |
---|
325 | f1 = f1 - a0; |
---|
326 | f2 = f2+2*bsquare*(4.0-a0-3*std::log((1+bsquare)/bsquare)); |
---|
327 | } |
---|
328 | g1=0.5*(3*f1-f2); |
---|
329 | g2=0.25*(3*f1+f2); |
---|
330 | if (icase==1) { |
---|
331 | return g1; |
---|
332 | } |
---|
333 | else |
---|
334 | { |
---|
335 | return g2; |
---|
336 | } |
---|
337 | } |
---|
338 | |
---|
339 | G4double G4PenelopeGammaConversion::CoulombCorrection(G4double a) |
---|
340 | { |
---|
341 | G4double fc=0; |
---|
342 | G4double b[7] = {0.202059,-0.03693,0.00835,-0.00201,0.00049,-0.00012,0.00003}; |
---|
343 | G4double aSquared = a*a; |
---|
344 | G4double aFourth = aSquared*aSquared; |
---|
345 | G4double aEighth = aFourth*aFourth; |
---|
346 | |
---|
347 | fc = ((1.0/(1.0+a*a))+b[0]+b[1]*aSquared+b[2]*aFourth+b[3]*(aSquared*aFourth)+ |
---|
348 | b[4]*aEighth+b[5]*(aEighth*aSquared)+b[6]*(aEighth*aFourth)); |
---|
349 | fc=aSquared*fc; |
---|
350 | return fc; |
---|
351 | } |
---|
352 | |
---|
353 | G4double G4PenelopeGammaConversion::LowEnergyCorrection(G4double a,G4double eki) |
---|
354 | { |
---|
355 | G4double f0=0,t=0; |
---|
356 | G4double b[12] = {-1.744,-12.10,11.18,8.523,73.26,-41.41,-13.52,-121.1,94.41,8.946,62.05,-63.41}; |
---|
357 | t=std::sqrt(2.0*eki); |
---|
358 | G4double tSq = t*t; |
---|
359 | f0=(b[0]+b[1]*a+b[2]*a*a)*t+(b[3]+b[4]*a+b[5]*a*a)*(tSq)+(b[6]+b[7]*a+b[8]*a*a)*(tSq*t)+ |
---|
360 | (b[9]+b[10]*a+b[11]*a*a)*(tSq*tSq); |
---|
361 | return f0; |
---|
362 | } |
---|
363 | |
---|
364 | G4double G4PenelopeGammaConversion::GetScreeningRadius(G4double Z) |
---|
365 | { |
---|
366 | char* path = getenv("G4LEDATA"); |
---|
367 | if (!path) |
---|
368 | { |
---|
369 | G4String excep = "G4PenelopeGammaConversion - G4LEDATA environment variable not set!"; |
---|
370 | G4Exception(excep); |
---|
371 | } |
---|
372 | G4String pathString(path); |
---|
373 | G4String pathFile = pathString + "/penelope/pp-pen.dat"; |
---|
374 | std::ifstream file(pathFile); |
---|
375 | std::filebuf* lsdp = file.rdbuf(); |
---|
376 | |
---|
377 | if (!(lsdp->is_open())) |
---|
378 | { |
---|
379 | G4String excep = "G4PenelopeGammaConversion - data file " + pathFile + "not found!"; |
---|
380 | G4Exception(excep); |
---|
381 | } |
---|
382 | G4int k; |
---|
383 | G4double a1,a2; |
---|
384 | while(!file.eof()) { |
---|
385 | file >> k >> a1 >> a2; |
---|
386 | if ((G4double) k == Z) |
---|
387 | { |
---|
388 | return a1; |
---|
389 | } |
---|
390 | } |
---|
391 | G4String excep = "G4PenelopeGammaConversion - Screening Radius for not found in the data file"; |
---|
392 | G4Exception(excep); |
---|
393 | return 0; |
---|
394 | } |
---|