source: trunk/source/processes/electromagnetic/standard/src/G4ComptonScattering52.cc@ 1036

Last change on this file since 1036 was 1007, checked in by garnier, 17 years ago

update to geant4.9.2
File size: 18.1 KB
RevLine 
[819]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//
[961]26// $Id: G4ComptonScattering52.cc,v 1.7 2008/10/15 17:53:44 vnivanch Exp $
[1007]27// GEANT4 tag $Name: geant4-09-02 $
[819]28//
29//
30//------------ G4ComptonScattering52 physics process -----------------------------
31// by Michel Maire, April 1996
32//
33// 28-05-96, DoIt() small change in ElecDirection, by M.Maire
34// 10-06-96, simplification in ComputeMicroscopicCrossSection(), by M.Maire
35// 21-06-96, SetCuts implementation, M.Maire
36// 13-09-96, small changes in DoIt for better efficiency. Thanks to P.Urban
37// 06-01-97, crossection table + meanfreepath table, M.Maire
38// 05-03-97, new Physics scheme, M.Maire
39// 28-03-97, protection in BuildPhysicsTable, M.Maire
40// 07-04-98, remove 'tracking cut' of the scattered gamma, MMa
41// 04-06-98, in DoIt, secondary production condition:
42// range>std::min(threshold,safety)
43// 13-08-98, new methods SetBining() PrintInfo()
44// 15-12-98, cross section=0 below 10 keV
45// 28-05-01, V.Ivanchenko minor changes to provide ANSI -wall compilation
46// 13-07-01, DoIt: suppression of production cut for the electron (mma)
47// 03-08-01, new methods Store/Retrieve PhysicsTable (mma)
48// 06-08-01, BuildThePhysicsTable() called from constructor (mma)
49// 17-09-01, migration of Materials to pure STL (mma)
50// 20-09-01, DoIt: fminimalEnergy = 1*eV (mma)
51// 01-10-01, come back to BuildPhysicsTable(const G4ParticleDefinition&)
52// 17-04-02, LowestEnergyLimit = 1*keV
53// 26-05-04, cross section parametrization improved for low energy :
54// Egamma <~ 15 keV (Laszlo)
55// 08-11-04, Remove Store/Retrieve tables (V.Ivanchenko)
56// 04-05-05, Add 52 to class name (V.Ivanchenko)
57// -----------------------------------------------------------------------------
58
59#include "G4ComptonScattering52.hh"
60#include "G4UnitsTable.hh"
61#include "G4PhysicsTableHelper.hh"
62
63//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
64
65using namespace std;
66
67G4ComptonScattering52::G4ComptonScattering52(const G4String& processName,
68 G4ProcessType type):G4VDiscreteProcess (processName, type),
69 theCrossSectionTable(NULL),
70 theMeanFreePathTable(NULL),
71 LowestEnergyLimit ( 1*keV),
72 HighestEnergyLimit(100*GeV),
73 NumbBinTable(80),
74 fminimalEnergy(1*eV)
[961]75{
76 SetProcessSubType(13);
77 G4cout << "!!! G4ComptonScattering52 is the obsolete process class and will be removed soon !!!"
78 << G4endl;
79}
[819]80
81//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
82
83// destructor
84
85G4ComptonScattering52::~G4ComptonScattering52()
86{
87 if (theCrossSectionTable) {
88 theCrossSectionTable->clearAndDestroy();
89 delete theCrossSectionTable;
90 }
91
92 if (theMeanFreePathTable) {
93 theMeanFreePathTable->clearAndDestroy();
94 delete theMeanFreePathTable;
95 }
96}
97
98//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
99
100G4bool G4ComptonScattering52::IsApplicable( const G4ParticleDefinition& particle)
101{
102 return ( &particle == G4Gamma::Gamma() );
103}
104
105//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
106
107void G4ComptonScattering52::SetPhysicsTableBining(
108 G4double lowE, G4double highE, G4int nBins)
109{
110 LowestEnergyLimit = lowE; HighestEnergyLimit = highE; NumbBinTable = nBins;
111}
112
113//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
114
115void G4ComptonScattering52::BuildPhysicsTable(const G4ParticleDefinition&)
116// Build cross section and mean free path tables
117{
118 G4double LowEdgeEnergy, Value;
119 G4PhysicsLogVector* ptrVector;
120
121// Build cross section per atom tables for the Compton Scattering process
122
123 if (theCrossSectionTable) {
124 theCrossSectionTable->clearAndDestroy(); delete theCrossSectionTable;}
125
126 theCrossSectionTable = new G4PhysicsTable(G4Element::GetNumberOfElements());
127 const G4ElementTable* theElementTable = G4Element::GetElementTable();
128 G4double AtomicNumber;
129 size_t J;
130
131 for ( J=0 ; J < G4Element::GetNumberOfElements(); J++ )
132 {
133 //create physics vector then fill it ....
134 ptrVector = new G4PhysicsLogVector(LowestEnergyLimit,HighestEnergyLimit,
135 NumbBinTable );
136 AtomicNumber = (*theElementTable)[J]->GetZ();
137
138 for ( G4int i = 0 ; i < NumbBinTable ; i++ )
139 {
140 LowEdgeEnergy = ptrVector->GetLowEdgeEnergy(i);
141 Value = ComputeCrossSectionPerAtom(LowEdgeEnergy, AtomicNumber);
142 ptrVector->PutValue(i,Value);
143 }
144
145 theCrossSectionTable->insertAt( J , ptrVector ) ;
146
147 }
148
149// Build mean free path table for the Compton Scattering process
150
151 if (theMeanFreePathTable) {
152 theMeanFreePathTable->clearAndDestroy(); delete theMeanFreePathTable;}
153
154 theMeanFreePathTable= new G4PhysicsTable(G4Material::GetNumberOfMaterials());
155 const G4MaterialTable* theMaterialTable = G4Material::GetMaterialTable();
156 G4Material* material;
157
158 for ( J=0 ; J < G4Material::GetNumberOfMaterials(); J++ )
159 {
160 //create physics vector then fill it ....
161 ptrVector = new G4PhysicsLogVector(LowestEnergyLimit,HighestEnergyLimit,
162 NumbBinTable ) ;
163 material = (*theMaterialTable)[J];
164
165 for ( G4int i = 0 ; i < NumbBinTable ; i++ )
166 {
167 LowEdgeEnergy = ptrVector->GetLowEdgeEnergy( i ) ;
168 Value = ComputeMeanFreePath( LowEdgeEnergy, material);
169 ptrVector->PutValue( i , Value ) ;
170 }
171
172 theMeanFreePathTable->insertAt( J , ptrVector ) ;
173 }
174
175 PrintInfoDefinition();
176
177}
178
179//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
180
181G4double G4ComptonScattering52::ComputeCrossSectionPerAtom
182 (G4double GammaEnergy, G4double Z)
183
184// Calculates the cross section per atom in GEANT4 internal units.
185// A parametrized formula from L. Urban is used to estimate
186// the total cross section.
187// It gives a good description of the data from 10 keV to 100/Z GeV.
188// lower limit 1 keV now with a correction for low energy
189
190{
191 G4double CrossSection = 0.0 ;
192 if ( Z < 1. ) return CrossSection;
193 if ( GammaEnergy < 1.*keV ) return CrossSection;
194 if ( GammaEnergy > (100.*GeV/Z) ) return CrossSection;
195
196 static const G4double a = 20.0 , b = 230.0 , c = 440.0;
197
198 static const G4double
199 d1= 2.7965e-1*barn, d2=-1.8300e-1*barn, d3= 6.7527 *barn, d4=-1.9798e+1*barn,
200 e1= 1.9756e-5*barn, e2=-1.0205e-2*barn, e3=-7.3913e-2*barn, e4= 2.7079e-2*barn,
201 f1=-3.9178e-7*barn, f2= 6.8241e-5*barn, f3= 6.0480e-5*barn, f4= 3.0274e-4*barn;
202
203 G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = Z*(d2 + e2*Z + f2*Z*Z),
204 p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = Z*(d4 + e4*Z + f4*Z*Z);
205
206 G4double T0 = 15*keV; if (Z == 1.) T0 = 40*keV;
207
208 G4double X = max(GammaEnergy, T0) / electron_mass_c2;
209 CrossSection = p1Z*log(1.+2*X)/X
210 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
211
212 // modification for low energy. (special case for Hydrogen)
213 if (GammaEnergy < T0) {
214 G4double dT0 = 1.*keV;
215 X = (T0+dT0) / electron_mass_c2 ;
216 G4double sigma = p1Z*log(1.+2*X)/X
217 + (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
218 G4double c1 = -T0*(sigma-CrossSection)/(CrossSection*dT0);
219 G4double c2 = 0.150; if (Z > 1.) c2 = 0.375-0.0556*log(Z);
220 G4double y = log(GammaEnergy/T0);
221 CrossSection *= exp(-y*(c1+c2*y));
222 }
223
224 return CrossSection;
225}
226
227//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
228
229G4double G4ComptonScattering52::ComputeMeanFreePath(G4double GammaEnergy,
230 G4Material* aMaterial)
231
232// returns the gamma mean free path in GEANT4 internal units
233
234{
235 const G4ElementVector* theElementVector = aMaterial->GetElementVector() ;
236 const G4double* NbOfAtomsPerVolume = aMaterial->GetVecNbOfAtomsPerVolume();
237
238 G4double SIGMA = 0.;
239
240 for ( size_t elm=0 ; elm < aMaterial->GetNumberOfElements() ; elm++ )
241 {
242 SIGMA += NbOfAtomsPerVolume[elm] *
243 ComputeCrossSectionPerAtom(GammaEnergy,
244 (*theElementVector)[elm]->GetZ());
245 }
246 return SIGMA > DBL_MIN ? 1./SIGMA : DBL_MAX;
247}
248
249 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
250
251G4double G4ComptonScattering52::GetCrossSectionPerAtom(
252 G4DynamicParticle* aDynamicGamma,
253 G4Element* anElement)
254
255// gives the microscopic total cross section in GEANT4 internal units
256
257{
258 G4double crossSection;
259 G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
260 G4bool isOutRange ;
261 if (GammaEnergy < LowestEnergyLimit || GammaEnergy > HighestEnergyLimit)
262 crossSection = 0.;
263 else
264 crossSection = (*theCrossSectionTable)(anElement->GetIndex())->
265 GetValue(GammaEnergy, isOutRange);
266
267 return crossSection;
268}
269
270//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
271
272
273G4double G4ComptonScattering52::GetMeanFreePath(const G4Track& aTrack,
274 G4double,
275 G4ForceCondition*)
276
277// returns the gamma mean free path in GEANT4 internal units
278
279{
280 const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
281 G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
282 G4Material* aMaterial = aTrack.GetMaterial();
283
284 G4double MeanFreePath;
285 G4bool isOutRange;
286
287 if (GammaEnergy > HighestEnergyLimit || GammaEnergy < LowestEnergyLimit)
288 MeanFreePath = DBL_MAX;
289 else
290 MeanFreePath = (*theMeanFreePathTable)(aMaterial->GetIndex())->
291 GetValue(GammaEnergy, isOutRange);
292 return MeanFreePath;
293}
294
295//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
296
297G4VParticleChange* G4ComptonScattering52::PostStepDoIt(const G4Track& aTrack,
298 const G4Step& aStep)
299//
300// The scattered gamma energy is sampled according to Klein - Nishina formula.
301// The random number techniques of Butcher & Messel are used
302// (Nuc Phys 20(1960),15).
303// GEANT4 internal units
304//
305// Note : Effects due to binding of atomic electrons are negliged.
306
307{
308 aParticleChange.Initialize(aTrack);
309
310 const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
311 G4double GammaEnergy0 = aDynamicGamma->GetKineticEnergy();
312 G4double E0_m = GammaEnergy0 / electron_mass_c2 ;
313
314 G4ParticleMomentum GammaDirection0 = aDynamicGamma->GetMomentumDirection();
315
316 //
317 // sample the energy rate of the scattered gamma
318 //
319
320 G4double epsilon, epsilonsq, onecost, sint2, greject ;
321
322 G4double epsilon0 = 1./(1. + 2*E0_m) , epsilon0sq = epsilon0*epsilon0;
323 G4double alpha1 = - log(epsilon0) , alpha2 = 0.5*(1.- epsilon0sq);
324
325 do {
326 if ( alpha1/(alpha1+alpha2) > G4UniformRand() )
327 { epsilon = exp(-alpha1*G4UniformRand()); // epsilon0**r
328 epsilonsq = epsilon*epsilon; }
329 else {
330 epsilonsq = epsilon0sq + (1.- epsilon0sq)*G4UniformRand();
331 epsilon = sqrt(epsilonsq);
332 };
333 onecost = (1.- epsilon)/(epsilon*E0_m);
334 sint2 = onecost*(2.-onecost);
335 greject = 1. - epsilon*sint2/(1.+ epsilonsq);
336 } while (greject < G4UniformRand());
337
338 //
339 // scattered gamma angles. ( Z - axis along the parent gamma)
340 //
341
342 G4double cosTeta = 1. - onecost , sinTeta = sqrt (sint2);
343 G4double Phi = twopi * G4UniformRand();
344 G4double dirx = sinTeta*cos(Phi), diry = sinTeta*sin(Phi), dirz = cosTeta;
345
346 //
347 // update G4VParticleChange for the scattered gamma
348 //
349
350 G4ThreeVector GammaDirection1 ( dirx,diry,dirz );
351 GammaDirection1.rotateUz(GammaDirection0);
352 aParticleChange.ProposeMomentumDirection( GammaDirection1 );
353 G4double GammaEnergy1 = epsilon*GammaEnergy0;
354 G4double localEnergyDeposit = 0.;
355
356 if (GammaEnergy1 > fminimalEnergy)
357 {
358 aParticleChange.ProposeEnergy( GammaEnergy1 );
359 }
360 else
361 {
362 localEnergyDeposit += GammaEnergy1;
363 aParticleChange.ProposeEnergy(0.) ;
364 aParticleChange.ProposeTrackStatus(fStopAndKill);
365 }
366
367 //
368 // kinematic of the scattered electron
369 //
370
371 G4double ElecKineEnergy = GammaEnergy0 - GammaEnergy1;
372
373 if (ElecKineEnergy > fminimalEnergy)
374 {
375 G4double ElecMomentum = sqrt(ElecKineEnergy*
376 (ElecKineEnergy+2.*electron_mass_c2));
377 G4ThreeVector ElecDirection (
378 (GammaEnergy0*GammaDirection0 - GammaEnergy1*GammaDirection1)
379 *(1./ElecMomentum) );
380
381 // create G4DynamicParticle object for the electron.
382 G4DynamicParticle* aElectron= new G4DynamicParticle(
383 G4Electron::Electron(),ElecDirection,ElecKineEnergy);
384
385 aParticleChange.SetNumberOfSecondaries(1);
386 aParticleChange.AddSecondary( aElectron );
387 }
388 else
389 {
390 aParticleChange.SetNumberOfSecondaries(0);
391 localEnergyDeposit += ElecKineEnergy;
392 }
393 aParticleChange.ProposeLocalEnergyDeposit (localEnergyDeposit);
394
395 // Reset NbOfInteractionLengthLeft and return aParticleChange
396 return G4VDiscreteProcess::PostStepDoIt( aTrack, aStep);
397}
398
399//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
400
401G4bool G4ComptonScattering52::StorePhysicsTable(const G4ParticleDefinition* particle,
402 const G4String& directory,
403 G4bool ascii)
404{
405 G4String filename;
406
407 // store cross section table
408 filename = GetPhysicsTableFileName(particle,directory,"CrossSection",ascii);
409 if ( !theCrossSectionTable->StorePhysicsTable(filename, ascii) ){
410 G4cout << " FAIL theCrossSectionTable->StorePhysicsTable in " << filename
411 << G4endl;
412 return false;
413 }
414
415 // store mean free path table
416 filename = GetPhysicsTableFileName(particle,directory,"MeanFreePath",ascii);
417 if ( !theMeanFreePathTable->StorePhysicsTable(filename, ascii) ){
418 G4cout << " FAIL theMeanFreePathTable->StorePhysicsTable in " << filename
419 << G4endl;
420 return false;
421 }
422
423 G4cout << GetProcessName() << " for " << particle->GetParticleName()
424 << ": Success to store the PhysicsTables in "
425 << directory << G4endl;
426 return true;
427}
428
429//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
430/*
431G4bool G4ComptonScattering52::RetrievePhysicsTable(const G4ParticleDefinition* particle,
432 const G4String& directory,
433 G4bool ascii)
434{
435 // delete theCrossSectionTable and theMeanFreePathTable
436 if (theCrossSectionTable != 0) {
437 theCrossSectionTable->clearAndDestroy();
438 delete theCrossSectionTable;
439 }
440 if (theMeanFreePathTable != 0) {
441 theMeanFreePathTable->clearAndDestroy();
442 delete theMeanFreePathTable;
443 }
444
445 G4String filename;
446
447 // retreive cross section table
448 filename = GetPhysicsTableFileName(particle,directory,"CrossSection",ascii);
449 theCrossSectionTable = new G4PhysicsTable(G4Element::GetNumberOfElements());
450 if ( !G4PhysicsTableHelper::RetrievePhysicsTable(filename, ascii) ){
451 G4cout << " FAIL theCrossSectionTable->RetrievePhysicsTable in " << filename
452 << G4endl;
453 return false;
454 }
455
456 // retreive mean free path table
457 filename = GetPhysicsTableFileName(particle,directory,"MeanFreePath",ascii);
458 theMeanFreePathTable = new G4PhysicsTable(G4Material::GetNumberOfMaterials());
459 if ( !G4PhysicsTableHelper::RetrievePhysicsTable(filename, ascii) ){
460 G4cout << " FAIL theMeanFreePathTable->RetrievePhysicsTable in " << filename
461 << G4endl;
462 return false;
463 }
464
465 G4cout << GetProcessName() << " for " << particle->GetParticleName()
466 << ": Success to retrieve the PhysicsTables from "
467 << directory << G4endl;
468 return true;
469}
470*/
471//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
472
473void G4ComptonScattering52::PrintInfoDefinition()
474{
475 G4String comments = "Total cross sections from a parametrisation. ";
476 comments += "Good description from 10 KeV to (100/Z) GeV. \n";
477 comments += " Scattered gamma energy according Klein-Nishina.";
478
479 G4cout << G4endl << GetProcessName() << ": " << comments
480 << "\n PhysicsTables from "
481 << G4BestUnit(LowestEnergyLimit,"Energy")
482 << " to " << G4BestUnit(HighestEnergyLimit,"Energy")
483 << " in " << NumbBinTable << " bins. \n";
484 G4cout << " WARNING: This process is obsolete and will be soon removed"
485 << G4endl;
486}
487
488//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
Note: See TracBrowser for help on using the repository browser.