source: trunk/source/processes/electromagnetic/xrays/src/G4Scintillation.cc@ 1036

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

update to geant4.9.2
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[819]1//
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25//
26//
[961]27// $Id: G4Scintillation.cc,v 1.30 2008/10/22 01:19:11 gum Exp $
[1007]28// GEANT4 tag $Name: geant4-09-02 $
[819]29//
30////////////////////////////////////////////////////////////////////////
31// Scintillation Light Class Implementation
32////////////////////////////////////////////////////////////////////////
33//
34// File: G4Scintillation.cc
35// Description: RestDiscrete Process - Generation of Scintillation Photons
36// Version: 1.0
37// Created: 1998-11-07
38// Author: Peter Gumplinger
39// Updated: 2005-08-17 by Peter Gumplinger
40// > change variable name MeanNumPhotons -> MeanNumberOfPhotons
41// 2005-07-28 by Peter Gumplinger
42// > add G4ProcessType to constructor
43// 2004-08-05 by Peter Gumplinger
44// > changed StronglyForced back to Forced in GetMeanLifeTime
45// 2002-11-21 by Peter Gumplinger
46// > change to use G4Poisson for small MeanNumberOfPhotons
47// 2002-11-07 by Peter Gumplinger
48// > now allow for fast and slow scintillation component
49// 2002-11-05 by Peter Gumplinger
50// > now use scintillation constants from G4Material
51// 2002-05-09 by Peter Gumplinger
52// > use only the PostStepPoint location for the origin of
53// scintillation photons when energy is lost to the medium
54// by a neutral particle
55// 2000-09-18 by Peter Gumplinger
56// > change: aSecondaryPosition=x0+rand*aStep.GetDeltaPosition();
57// aSecondaryTrack->SetTouchable(0);
58// 2001-09-17, migration of Materials to pure STL (mma)
59// 2003-06-03, V.Ivanchenko fix compilation warnings
60//
61// mail: gum@triumf.ca
62//
63////////////////////////////////////////////////////////////////////////
64
65#include "G4ios.hh"
[961]66#include "G4EmProcessSubType.hh"
67
[819]68#include "G4Scintillation.hh"
69
70using namespace std;
71
72/////////////////////////
73// Class Implementation
74/////////////////////////
75
76 //////////////
77 // Operators
78 //////////////
79
80// G4Scintillation::operator=(const G4Scintillation &right)
81// {
82// }
83
84 /////////////////
85 // Constructors
86 /////////////////
87
88G4Scintillation::G4Scintillation(const G4String& processName,
89 G4ProcessType type)
90 : G4VRestDiscreteProcess(processName, type)
91{
[961]92 SetProcessSubType(fScintillation);
93
[819]94 fTrackSecondariesFirst = false;
95
96 YieldFactor = 1.0;
97 ExcitationRatio = 1.0;
98
99 theFastIntegralTable = NULL;
100 theSlowIntegralTable = NULL;
101
102 if (verboseLevel>0) {
103 G4cout << GetProcessName() << " is created " << G4endl;
104 }
105
106 BuildThePhysicsTable();
[961]107
108 emSaturation = NULL;
[819]109}
110
111 ////////////////
112 // Destructors
113 ////////////////
114
115G4Scintillation::~G4Scintillation()
116{
117 if (theFastIntegralTable != NULL) {
118 theFastIntegralTable->clearAndDestroy();
119 delete theFastIntegralTable;
120 }
121 if (theSlowIntegralTable != NULL) {
122 theSlowIntegralTable->clearAndDestroy();
123 delete theSlowIntegralTable;
124 }
125}
126
127 ////////////
128 // Methods
129 ////////////
130
131// AtRestDoIt
132// ----------
133//
134G4VParticleChange*
135G4Scintillation::AtRestDoIt(const G4Track& aTrack, const G4Step& aStep)
136
137// This routine simply calls the equivalent PostStepDoIt since all the
138// necessary information resides in aStep.GetTotalEnergyDeposit()
139
140{
141 return G4Scintillation::PostStepDoIt(aTrack, aStep);
142}
143
144// PostStepDoIt
145// -------------
146//
147G4VParticleChange*
148G4Scintillation::PostStepDoIt(const G4Track& aTrack, const G4Step& aStep)
149
150// This routine is called for each tracking step of a charged particle
151// in a scintillator. A Poisson/Gauss-distributed number of photons is
152// generated according to the scintillation yield formula, distributed
153// evenly along the track segment and uniformly into 4pi.
154
155{
156 aParticleChange.Initialize(aTrack);
157
158 const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
159 const G4Material* aMaterial = aTrack.GetMaterial();
160
161 G4StepPoint* pPreStepPoint = aStep.GetPreStepPoint();
162 G4StepPoint* pPostStepPoint = aStep.GetPostStepPoint();
163
164 G4ThreeVector x0 = pPreStepPoint->GetPosition();
165 G4ThreeVector p0 = aStep.GetDeltaPosition().unit();
166 G4double t0 = pPreStepPoint->GetGlobalTime();
167
168 G4double TotalEnergyDeposit = aStep.GetTotalEnergyDeposit();
169
170 G4MaterialPropertiesTable* aMaterialPropertiesTable =
171 aMaterial->GetMaterialPropertiesTable();
172 if (!aMaterialPropertiesTable)
173 return G4VRestDiscreteProcess::PostStepDoIt(aTrack, aStep);
174
175 const G4MaterialPropertyVector* Fast_Intensity =
176 aMaterialPropertiesTable->GetProperty("FASTCOMPONENT");
177 const G4MaterialPropertyVector* Slow_Intensity =
178 aMaterialPropertiesTable->GetProperty("SLOWCOMPONENT");
179
180 if (!Fast_Intensity && !Slow_Intensity )
181 return G4VRestDiscreteProcess::PostStepDoIt(aTrack, aStep);
182
183 G4int nscnt = 1;
184 if (Fast_Intensity && Slow_Intensity) nscnt = 2;
185
186 G4double ScintillationYield = aMaterialPropertiesTable->
187 GetConstProperty("SCINTILLATIONYIELD");
[961]188 ScintillationYield *= YieldFactor;
189
[819]190 G4double ResolutionScale = aMaterialPropertiesTable->
191 GetConstProperty("RESOLUTIONSCALE");
192
[961]193 // Birks law saturation:
[819]194
[961]195 G4double constBirks = 0.0;
[819]196
[961]197 constBirks = aMaterial->GetIonisation()->GetBirksConstant();
198
199 G4double MeanNumberOfPhotons;
200
201 if (emSaturation) {
202 MeanNumberOfPhotons = ScintillationYield*
203 (emSaturation->VisibleEnergyDeposition(&aStep));
204 } else {
205 MeanNumberOfPhotons = ScintillationYield*TotalEnergyDeposit;
206 }
207
[819]208 G4int NumPhotons;
[961]209
210 if (MeanNumberOfPhotons > 10.)
211 {
[819]212 G4double sigma = ResolutionScale * sqrt(MeanNumberOfPhotons);
213 NumPhotons = G4int(G4RandGauss::shoot(MeanNumberOfPhotons,sigma)+0.5);
214 }
[961]215 else
216 {
[819]217 NumPhotons = G4int(G4Poisson(MeanNumberOfPhotons));
218 }
219
[961]220 if (NumPhotons <= 0)
221 {
[819]222 // return unchanged particle and no secondaries
223
224 aParticleChange.SetNumberOfSecondaries(0);
225
226 return G4VRestDiscreteProcess::PostStepDoIt(aTrack, aStep);
227 }
228
229 ////////////////////////////////////////////////////////////////
230
231 aParticleChange.SetNumberOfSecondaries(NumPhotons);
232
233 if (fTrackSecondariesFirst) {
234 if (aTrack.GetTrackStatus() == fAlive )
235 aParticleChange.ProposeTrackStatus(fSuspend);
236 }
237
238 ////////////////////////////////////////////////////////////////
239
240 G4int materialIndex = aMaterial->GetIndex();
241
242 // Retrieve the Scintillation Integral for this material
243 // new G4PhysicsOrderedFreeVector allocated to hold CII's
244
245 G4int Num = NumPhotons;
246
247 for (G4int scnt = 1; scnt <= nscnt; scnt++) {
248
249 G4double ScintillationTime = 0.*ns;
250 G4PhysicsOrderedFreeVector* ScintillationIntegral = NULL;
251
252 if (scnt == 1) {
253 if (nscnt == 1) {
254 if(Fast_Intensity){
255 ScintillationTime = aMaterialPropertiesTable->
256 GetConstProperty("FASTTIMECONSTANT");
257 ScintillationIntegral =
258 (G4PhysicsOrderedFreeVector*)((*theFastIntegralTable)(materialIndex));
259 }
260 if(Slow_Intensity){
261 ScintillationTime = aMaterialPropertiesTable->
262 GetConstProperty("SLOWTIMECONSTANT");
263 ScintillationIntegral =
264 (G4PhysicsOrderedFreeVector*)((*theSlowIntegralTable)(materialIndex));
265 }
266 }
267 else {
268 G4double YieldRatio = aMaterialPropertiesTable->
269 GetConstProperty("YIELDRATIO");
270 if ( ExcitationRatio == 1.0 ) {
271 Num = G4int (min(YieldRatio,1.0) * NumPhotons);
272 }
273 else {
274 Num = G4int (min(ExcitationRatio,1.0) * NumPhotons);
275 }
276 ScintillationTime = aMaterialPropertiesTable->
277 GetConstProperty("FASTTIMECONSTANT");
278 ScintillationIntegral =
279 (G4PhysicsOrderedFreeVector*)((*theFastIntegralTable)(materialIndex));
280 }
281 }
282 else {
283 Num = NumPhotons - Num;
284 ScintillationTime = aMaterialPropertiesTable->
285 GetConstProperty("SLOWTIMECONSTANT");
286 ScintillationIntegral =
287 (G4PhysicsOrderedFreeVector*)((*theSlowIntegralTable)(materialIndex));
288 }
289
290 if (!ScintillationIntegral) continue;
291
292 // Max Scintillation Integral
293
294 G4double CIImax = ScintillationIntegral->GetMaxValue();
295
296 for (G4int i = 0; i < Num; i++) {
297
[961]298 // Determine photon energy
[819]299
300 G4double CIIvalue = G4UniformRand()*CIImax;
[961]301 G4double sampledEnergy =
[819]302 ScintillationIntegral->GetEnergy(CIIvalue);
303
304 if (verboseLevel>1) {
[961]305 G4cout << "sampledEnergy = " << sampledEnergy << G4endl;
[819]306 G4cout << "CIIvalue = " << CIIvalue << G4endl;
307 }
308
309 // Generate random photon direction
310
311 G4double cost = 1. - 2.*G4UniformRand();
312 G4double sint = sqrt((1.-cost)*(1.+cost));
313
314 G4double phi = twopi*G4UniformRand();
315 G4double sinp = sin(phi);
316 G4double cosp = cos(phi);
317
318 G4double px = sint*cosp;
319 G4double py = sint*sinp;
320 G4double pz = cost;
321
322 // Create photon momentum direction vector
323
324 G4ParticleMomentum photonMomentum(px, py, pz);
325
326 // Determine polarization of new photon
327
328 G4double sx = cost*cosp;
329 G4double sy = cost*sinp;
330 G4double sz = -sint;
331
332 G4ThreeVector photonPolarization(sx, sy, sz);
333
334 G4ThreeVector perp = photonMomentum.cross(photonPolarization);
335
336 phi = twopi*G4UniformRand();
337 sinp = sin(phi);
338 cosp = cos(phi);
339
340 photonPolarization = cosp * photonPolarization + sinp * perp;
341
342 photonPolarization = photonPolarization.unit();
343
344 // Generate a new photon:
345
346 G4DynamicParticle* aScintillationPhoton =
347 new G4DynamicParticle(G4OpticalPhoton::OpticalPhoton(),
348 photonMomentum);
349 aScintillationPhoton->SetPolarization
350 (photonPolarization.x(),
351 photonPolarization.y(),
352 photonPolarization.z());
353
[961]354 aScintillationPhoton->SetKineticEnergy(sampledEnergy);
[819]355
356 // Generate new G4Track object:
357
358 G4double rand;
359
360 if (aParticle->GetDefinition()->GetPDGCharge() != 0) {
361 rand = G4UniformRand();
362 } else {
363 rand = 1.0;
364 }
365
366 G4double delta = rand * aStep.GetStepLength();
367 G4double deltaTime = delta /
368 ((pPreStepPoint->GetVelocity()+
369 pPostStepPoint->GetVelocity())/2.);
370
371 deltaTime = deltaTime -
372 ScintillationTime * log( G4UniformRand() );
373
374 G4double aSecondaryTime = t0 + deltaTime;
375
376 G4ThreeVector aSecondaryPosition =
377 x0 + rand * aStep.GetDeltaPosition();
378
379 G4Track* aSecondaryTrack =
380 new G4Track(aScintillationPhoton,aSecondaryTime,aSecondaryPosition);
381
[961]382 aSecondaryTrack->SetTouchableHandle(
383 aStep.GetPreStepPoint()->GetTouchableHandle());
384 // aSecondaryTrack->SetTouchableHandle((G4VTouchable*)0);
[819]385
386 aSecondaryTrack->SetParentID(aTrack.GetTrackID());
387
388 aParticleChange.AddSecondary(aSecondaryTrack);
389
390 }
391 }
392
393 if (verboseLevel>0) {
394 G4cout << "\n Exiting from G4Scintillation::DoIt -- NumberOfSecondaries = "
395 << aParticleChange.GetNumberOfSecondaries() << G4endl;
396 }
397
398 return G4VRestDiscreteProcess::PostStepDoIt(aTrack, aStep);
399}
400
401// BuildThePhysicsTable for the scintillation process
402// --------------------------------------------------
403//
404
405void G4Scintillation::BuildThePhysicsTable()
406{
407 if (theFastIntegralTable && theSlowIntegralTable) return;
408
409 const G4MaterialTable* theMaterialTable =
410 G4Material::GetMaterialTable();
411 G4int numOfMaterials = G4Material::GetNumberOfMaterials();
412
413 // create new physics table
414
415 if(!theFastIntegralTable)theFastIntegralTable = new G4PhysicsTable(numOfMaterials);
416 if(!theSlowIntegralTable)theSlowIntegralTable = new G4PhysicsTable(numOfMaterials);
417
418 // loop for materials
419
420 for (G4int i=0 ; i < numOfMaterials; i++)
421 {
422 G4PhysicsOrderedFreeVector* aPhysicsOrderedFreeVector =
423 new G4PhysicsOrderedFreeVector();
424 G4PhysicsOrderedFreeVector* bPhysicsOrderedFreeVector =
425 new G4PhysicsOrderedFreeVector();
426
427 // Retrieve vector of scintillation wavelength intensity for
428 // the material from the material's optical properties table.
429
430 G4Material* aMaterial = (*theMaterialTable)[i];
431
432 G4MaterialPropertiesTable* aMaterialPropertiesTable =
433 aMaterial->GetMaterialPropertiesTable();
434
435 if (aMaterialPropertiesTable) {
436
437 G4MaterialPropertyVector* theFastLightVector =
438 aMaterialPropertiesTable->GetProperty("FASTCOMPONENT");
439
440 if (theFastLightVector) {
441
442 // Retrieve the first intensity point in vector
[961]443 // of (photon energy, intensity) pairs
[819]444
445 theFastLightVector->ResetIterator();
446 ++(*theFastLightVector); // advance to 1st entry
447
448 G4double currentIN = theFastLightVector->
449 GetProperty();
450
451 if (currentIN >= 0.0) {
452
[961]453 // Create first (photon energy, Scintillation
[819]454 // Integral pair
455
456 G4double currentPM = theFastLightVector->
[961]457 GetPhotonEnergy();
[819]458
459 G4double currentCII = 0.0;
460
461 aPhysicsOrderedFreeVector->
462 InsertValues(currentPM , currentCII);
463
464 // Set previous values to current ones prior to loop
465
466 G4double prevPM = currentPM;
467 G4double prevCII = currentCII;
468 G4double prevIN = currentIN;
469
[961]470 // loop over all (photon energy, intensity)
[819]471 // pairs stored for this material
472
473 while(++(*theFastLightVector))
474 {
475 currentPM = theFastLightVector->
[961]476 GetPhotonEnergy();
[819]477
478 currentIN=theFastLightVector->
479 GetProperty();
480
481 currentCII = 0.5 * (prevIN + currentIN);
482
483 currentCII = prevCII +
484 (currentPM - prevPM) * currentCII;
485
486 aPhysicsOrderedFreeVector->
487 InsertValues(currentPM, currentCII);
488
489 prevPM = currentPM;
490 prevCII = currentCII;
491 prevIN = currentIN;
492 }
493
494 }
495 }
496
497 G4MaterialPropertyVector* theSlowLightVector =
498 aMaterialPropertiesTable->GetProperty("SLOWCOMPONENT");
499
500 if (theSlowLightVector) {
501
502 // Retrieve the first intensity point in vector
[961]503 // of (photon energy, intensity) pairs
[819]504
505 theSlowLightVector->ResetIterator();
506 ++(*theSlowLightVector); // advance to 1st entry
507
508 G4double currentIN = theSlowLightVector->
509 GetProperty();
510
511 if (currentIN >= 0.0) {
512
[961]513 // Create first (photon energy, Scintillation
[819]514 // Integral pair
515
516 G4double currentPM = theSlowLightVector->
[961]517 GetPhotonEnergy();
[819]518
519 G4double currentCII = 0.0;
520
521 bPhysicsOrderedFreeVector->
522 InsertValues(currentPM , currentCII);
523
524 // Set previous values to current ones prior to loop
525
526 G4double prevPM = currentPM;
527 G4double prevCII = currentCII;
528 G4double prevIN = currentIN;
529
[961]530 // loop over all (photon energy, intensity)
[819]531 // pairs stored for this material
532
533 while(++(*theSlowLightVector))
534 {
535 currentPM = theSlowLightVector->
[961]536 GetPhotonEnergy();
[819]537
538 currentIN=theSlowLightVector->
539 GetProperty();
540
541 currentCII = 0.5 * (prevIN + currentIN);
542
543 currentCII = prevCII +
544 (currentPM - prevPM) * currentCII;
545
546 bPhysicsOrderedFreeVector->
547 InsertValues(currentPM, currentCII);
548
549 prevPM = currentPM;
550 prevCII = currentCII;
551 prevIN = currentIN;
552 }
553
554 }
555 }
556 }
557
558 // The scintillation integral(s) for a given material
559 // will be inserted in the table(s) according to the
560 // position of the material in the material table.
561
562 theFastIntegralTable->insertAt(i,aPhysicsOrderedFreeVector);
563 theSlowIntegralTable->insertAt(i,bPhysicsOrderedFreeVector);
564
565 }
566}
567
568// GetMeanFreePath
569// ---------------
570//
571
572G4double G4Scintillation::GetMeanFreePath(const G4Track&,
573 G4double ,
574 G4ForceCondition* condition)
575{
576 *condition = StronglyForced;
577
578 return DBL_MAX;
579
580}
581
582// GetMeanLifeTime
583// ---------------
584//
585
586G4double G4Scintillation::GetMeanLifeTime(const G4Track&,
587 G4ForceCondition* condition)
588{
589 *condition = Forced;
590
591 return DBL_MAX;
592
593}
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