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25 //
26 //
27 // Author: Sebastien Incerti
28 // 30 October 2008
29 // on base of G4LowEnergyPolarizedRayleigh developed by R. Capra
30 //
31 // History:
32 // --------
33 // 02 May 2009 S Incerti as V. Ivanchenko proposed in G4LivermoreRayleighModel.cc
34 //
35 // Cleanup initialisation and generation of secondaries:
36 // - apply internal high-energy limit only in constructor
37 // - do not apply low-energy limit (default is 0)
38 // - remove GetMeanFreePath method and table
39 // - remove initialisation of element selector
40 // - use G4ElementSelector
41
42 #include "G4LivermorePolarizedRayleighModel.hh"
43 #include "G4PhysicalConstants.hh"
44 #include "G4SystemOfUnits.hh"
45 #include "G4LogLogInterpolation.hh"
46 #include "G4CompositeEMDataSet.hh"
47 #include "G4AutoLock.hh"
48
49 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
50
51 using namespace std;
52 namespace { G4Mutex LivermorePolarizedRayleighModelMutex = G4MUTEX_INITIALIZER; }
53
54 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
55
56 G4PhysicsFreeVector* G4LivermorePolarizedRayleighModel::dataCS[] = {nullptr};
57 G4PhysicsFreeVector* G4LivermorePolarizedRayleighModel::formFactorData[] = {nullptr};
58
59 G4LivermorePolarizedRayleighModel::G4LivermorePolarizedRayleighModel(const G4ParticleDefinition*,
60 const G4String& nam)
61 :G4VEmModel(nam),fParticleChange(nullptr),isInitialised(false)
62 {
63 lowEnergyLimit = 250 * CLHEP::eV;
64 //
65 verboseLevel= 0;
66 // Verbosity scale:
67 // 0 = nothing
68 // 1 = warning for energy non-conservation
69 // 2 = details of energy budget
70 // 3 = calculation of cross sections, file openings, sampling of atoms
71 // 4 = entering in methods
72
73 if(verboseLevel > 0) {
74 G4cout << "Livermore Polarized Rayleigh is constructed " << G4endl
75 << "Energy range: " << LowEnergyLimit() / CLHEP::eV << " eV - "
76 << HighEnergyLimit() / CLHEP::GeV << " GeV"
77 << G4endl;
78 }
79 }
80
81 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
82
83 G4LivermorePolarizedRayleighModel::~G4LivermorePolarizedRayleighModel()
84 {
85 if(IsMaster()) {
86 for(G4int i=0; i<maxZ; ++i) {
87 if(dataCS[i]) {
88 delete dataCS[i];
89 dataCS[i] = nullptr;
90 delete formFactorData[i];
91 formFactorData[i] = nullptr;
92 }
93 }
94 }
95 }
96
97 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98
99 void G4LivermorePolarizedRayleighModel::Initialise(const G4ParticleDefinition* particle,
100 const G4DataVector& cuts)
101 {
102 // Rayleigh process: The Quantum Theory of Radiation
103 // W. Heitler, Oxford at the Clarendon Press, Oxford (1954)
104 // Scattering function: A simple model of photon transport
105 // D.E. Cullen, Nucl. Instr. Meth. in Phys. Res. B 101 (1995) 499-510
106 // Polarization of the outcoming photon: Beam test of a prototype detector array for the PoGO astronomical hard
107 // X-ray/soft gamma-ray polarimeter
108 // T. Mizuno et al., Nucl. Instr. Meth. in Phys. Res. A 540 (2005) 158-168
109 if (verboseLevel > 3)
110 G4cout << "Calling G4LivermorePolarizedRayleighModel::Initialise()" << G4endl;
111
112 if(IsMaster()) {
113
114 // Initialise element selector
115 InitialiseElementSelectors(particle, cuts);
116
117 // Access to elements
118 const char* path = G4FindDataDir("G4LEDATA");
119 auto elmTable = G4Element::GetElementTable();
120 for (auto const & elm : *elmTable) {
121 G4int Z = std::min(elm->GetZasInt(), maxZ);
122 if( nullptr == dataCS[Z] ) { ReadData(Z, path); }
123 }
124 }
125
126 if(isInitialised) { return; }
127 fParticleChange = GetParticleChangeForGamma();
128 isInitialised = true;
129 }
130
131
132 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
133
134 void G4LivermorePolarizedRayleighModel::InitialiseLocal(
135 const G4ParticleDefinition*, G4VEmModel* masterModel)
136 {
137 SetElementSelectors(masterModel->GetElementSelectors());
138 }
139
140 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
141
142 void G4LivermorePolarizedRayleighModel::ReadData(std::size_t Z, const char* path)
143 {
144 if (verboseLevel > 1) {
145 G4cout << "Calling ReadData() of G4LivermoreRayleighModel"
146 << G4endl;
147 }
148
149 if(nullptr != dataCS[Z]) { return; }
150
151 const char* datadir = path;
152
153 if(nullptr == datadir)
154 {
155 datadir = G4FindDataDir("G4LEDATA");
156 if(nullptr == datadir)
157 {
158 G4Exception("G4LivermoreRayleighModelModel::ReadData()","em0006",
159 FatalException,
160 "Environment variable G4LEDATA not defined");
161 return;
162 }
163 }
164 dataCS[Z] = new G4PhysicsFreeVector();
165 formFactorData[Z] = new G4PhysicsFreeVector();
166
167 std::ostringstream ostCS;
168 ostCS << datadir << "/livermore/rayl/re-cs-" << Z <<".dat";
169 std::ifstream finCS(ostCS.str().c_str());
170
171 if( !finCS .is_open() ) {
172 G4ExceptionDescription ed;
173 ed << "G4LivermorePolarizedRayleighModel data file <" << ostCS.str().c_str()
174 << "> is not opened!" << G4endl;
175 G4Exception("G4LivermorePolarizedRayleighModel::ReadData()","em0003",
176 FatalException,
177 ed,"G4LEDATA version should be G4EMLOW8.0 or later.");
178 return;
179 } else {
180 if(verboseLevel > 3) {
181 G4cout << "File " << ostCS.str()
182 << " is opened by G4LivermoreRayleighModel" << G4endl;
183 }
184 dataCS[Z]->Retrieve(finCS, true);
185 }
186
187 std::ostringstream ostFF;
188 ostFF << datadir << "/livermore/rayl/re-ff-" << Z <<".dat";
189 std::ifstream finFF(ostFF.str().c_str());
190
191 if( !finFF.is_open() ) {
192 G4ExceptionDescription ed;
193 ed << "G4LivermorePolarizedRayleighModel data file <" << ostFF.str().c_str()
194 << "> is not opened!" << G4endl;
195 G4Exception("G4LivermorePolarizedRayleighModel::ReadData()","em0003",
196 FatalException,
197 ed,"G4LEDATA version should be G4EMLOW8.0 or later.");
198 return;
199 } else {
200 if(verboseLevel > 3) {
201 G4cout << "File " << ostFF.str()
202 << " is opened by G4LivermoreRayleighModel" << G4endl;
203 }
204 formFactorData[Z]->Retrieve(finFF, true);
205 }
206 }
207
208 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
209
210 G4double G4LivermorePolarizedRayleighModel::ComputeCrossSectionPerAtom(
211 const G4ParticleDefinition*,
212 G4double GammaEnergy,
213 G4double Z, G4double,
214 G4double, G4double)
215 {
216 if (verboseLevel > 1) {
217 G4cout << "G4LivermoreRayleighModel::ComputeCrossSectionPerAtom()"
218 << G4endl;
219 }
220
221 if(GammaEnergy < lowEnergyLimit) { return 0.0; }
222
223 G4double xs = 0.0;
224
225 G4int intZ = G4lrint(Z);
226 if(intZ < 1 || intZ > maxZ) { return xs; }
227
228 G4PhysicsFreeVector* pv = dataCS[intZ];
229
230 // if element was not initialised
231 // do initialisation safely for MT mode
232 if(nullptr == pv) {
233 InitialiseForElement(0, intZ);
234 pv = dataCS[intZ];
235 if(nullptr == pv) { return xs; }
236 }
237
238 G4int n = G4int(pv->GetVectorLength() - 1);
239 G4double e = GammaEnergy/MeV;
240 if(e >= pv->Energy(n)) {
241 xs = (*pv)[n]/(e*e);
242 } else if(e >= pv->Energy(0)) {
243 xs = pv->Value(e)/(e*e);
244 }
245 return xs;
246 }
247
248 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
249
250 void G4LivermorePolarizedRayleighModel::SampleSecondaries(
251 std::vector<G4DynamicParticle*>*,
252 const G4MaterialCutsCouple* couple,
253 const G4DynamicParticle* aDynamicGamma,
254 G4double, G4double)
255 {
256 if (verboseLevel > 3)
257 G4cout << "Calling SampleSecondaries() of G4LivermorePolarizedRayleighModel" << G4endl;
258
259 G4double photonEnergy0 = aDynamicGamma->GetKineticEnergy();
260
261 if (photonEnergy0 <= lowEnergyLimit)
262 {
263 fParticleChange->ProposeTrackStatus(fStopAndKill);
264 fParticleChange->SetProposedKineticEnergy(0.);
265 fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0);
266 return;
267 }
268
269 G4ParticleMomentum photonDirection0 = aDynamicGamma->GetMomentumDirection();
270
271 // Select randomly one element in the current material
272 const G4ParticleDefinition* particle = aDynamicGamma->GetDefinition();
273 const G4Element* elm = SelectRandomAtom(couple,particle,photonEnergy0);
274 G4int Z = elm->GetZasInt();
275
276 G4double outcomingPhotonCosTheta = GenerateCosTheta(photonEnergy0, Z);
277 G4double outcomingPhotonPhi = GeneratePhi(outcomingPhotonCosTheta);
278 G4double beta = GeneratePolarizationAngle();
279
280 // incomingPhoton reference frame:
281 // z = versor parallel to the incomingPhotonDirection
282 // x = versor parallel to the incomingPhotonPolarization
283 // y = defined as z^x
284
285 // outgoingPhoton reference frame:
286 // z' = versor parallel to the outgoingPhotonDirection
287 // x' = defined as x-x*z'z' normalized
288 // y' = defined as z'^x'
289 G4ThreeVector z(aDynamicGamma->GetMomentumDirection().unit());
290 G4ThreeVector x(GetPhotonPolarization(*aDynamicGamma));
291 G4ThreeVector y(z.cross(x));
292
293 // z' = std::cos(phi)*std::sin(theta)
294 // x + std::sin(phi)*std::sin(theta) y + std::cos(theta) z
295 G4double xDir;
296 G4double yDir;
297 G4double zDir;
298 zDir=outcomingPhotonCosTheta;
299 xDir=std::sqrt(1-outcomingPhotonCosTheta*outcomingPhotonCosTheta);
300 yDir=xDir;
301 xDir*=std::cos(outcomingPhotonPhi);
302 yDir*=std::sin(outcomingPhotonPhi);
303
304 G4ThreeVector zPrime((xDir*x + yDir*y + zDir*z).unit());
305 G4ThreeVector xPrime(x.perpPart(zPrime).unit());
306 G4ThreeVector yPrime(zPrime.cross(xPrime));
307
308 // outgoingPhotonPolarization is directed as
309 // x' std::cos(beta) + y' std::sin(beta)
310 G4ThreeVector outcomingPhotonPolarization(xPrime*std::cos(beta) + yPrime*std::sin(beta));
311
312 fParticleChange->ProposeMomentumDirection(zPrime);
313 fParticleChange->ProposePolarization(outcomingPhotonPolarization);
314 fParticleChange->SetProposedKineticEnergy(photonEnergy0);
315 }
316
317 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
318
319 G4double G4LivermorePolarizedRayleighModel::GenerateCosTheta(G4double incomingPhotonEnergy, G4int Z) const
320 {
321 // d sigma k0
322 // --------- = r0^2 * pi * F^2(x, Z) * ( 2 - sin^2 theta) * std::sin (theta), x = ---- std::sin(theta/2)
323 // d theta hc
324
325 // d sigma k0 1 - y
326 // --------- = r0^2 * pi * F^2(x, Z) * ( 1 + y^2), x = ---- std::sqrt ( ------- ), y = std::cos(theta)
327 // d y hc 2
328
329 // Z
330 // F(x, Z) ~ --------
331 // a + bx
332 //
333 // The time to exit from the outer loop grows as ~ k0
334 // On pcgeant2 the time is ~ 1 s for k0 ~ 1 MeV on the oxygen element. A 100 GeV
335 // event will take ~ 10 hours.
336 //
337 // On the avarage the inner loop does 1.5 iterations before exiting
338 const G4double xxfact = CLHEP::cm/(CLHEP::h_Planck*CLHEP::c_light);
339 const G4double xFactor = incomingPhotonEnergy*xxfact;
340
341 G4double cosTheta;
342 G4double fCosTheta;
343 G4double x;
344 G4double fValue;
345
346 if (incomingPhotonEnergy > 5.*CLHEP::MeV)
347 {
348 cosTheta = 1.;
349 }
350 else
351 {
352 do
353 {
354 do
355 {
356 cosTheta = 2.*G4UniformRand()-1.;
357 fCosTheta = (1.+cosTheta*cosTheta)/2.;
358 }
359 while (fCosTheta < G4UniformRand());
360
361 x = xFactor*std::sqrt((1.-cosTheta)/2.);
362
363 if (x > 1.e+005)
364 fValue = formFactorData[Z]->Value(x);
365 else
366 fValue = formFactorData[Z]->Value(0.);
367
368 fValue /= Z;
369 fValue *= fValue;
370 }
371 while(fValue < G4UniformRand());
372 }
373
374 return cosTheta;
375 }
376
377 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
378
379 G4double G4LivermorePolarizedRayleighModel::GeneratePhi(G4double cosTheta) const
380 {
381 // d sigma
382 // --------- = alpha * ( 1 - sin^2 (theta) * cos^2 (phi) )
383 // d phi
384
385 // On the average the loop takes no more than 2 iterations before exiting
386
387 G4double phi;
388 G4double cosPhi;
389 G4double phiProbability;
390 G4double sin2Theta;
391
392 sin2Theta=1.-cosTheta*cosTheta;
393
394 do
395 {
396 phi = CLHEP::twopi * G4UniformRand();
397 cosPhi = std::cos(phi);
398 phiProbability= 1. - sin2Theta*cosPhi*cosPhi;
399 }
400 while (phiProbability < G4UniformRand());
401
402 return phi;
403 }
404
405 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
406
407 G4double G4LivermorePolarizedRayleighModel::GeneratePolarizationAngle(void) const
408 {
409 // Rayleigh polarization is always on the x' direction
410 return 0;
411 }
412
413 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
414
415 G4ThreeVector G4LivermorePolarizedRayleighModel::GetPhotonPolarization(const G4DynamicParticle& photon)
416 {
417 // From G4VLowEnergyDiscretePhotonProcess.cc
418 G4ThreeVector photonMomentumDirection;
419 G4ThreeVector photonPolarization;
420
421 photonPolarization = photon.GetPolarization();
422 photonMomentumDirection = photon.GetMomentumDirection();
423
424 if ((!photonPolarization.isOrthogonal(photonMomentumDirection, 1e-6)) || photonPolarization.mag()==0.)
425 {
426 // if |photonPolarization|==0. or |photonPolarization * photonDirection0| > 1e-6 * |photonPolarization ^ photonDirection0|
427 // then polarization is choosen randomly.
428 G4ThreeVector e1(photonMomentumDirection.orthogonal().unit());
429 G4ThreeVector e2(photonMomentumDirection.cross(e1).unit());
430
431 G4double angle(G4UniformRand() * CLHEP::twopi);
432
433 e1*=std::cos(angle);
434 e2*=std::sin(angle);
435
436 photonPolarization=e1+e2;
437 }
438 else if (photonPolarization.howOrthogonal(photonMomentumDirection) != 0.)
439 {
440 // if |photonPolarization * photonDirection0| != 0.
441 // then polarization is made orthonormal;
442 photonPolarization=photonPolarization.perpPart(photonMomentumDirection);
443 }
444
445 return photonPolarization.unit();
446 }
447
448 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
449
450 void G4LivermorePolarizedRayleighModel::InitialiseForElement(
451 const G4ParticleDefinition*, G4int Z)
452 {
453 G4AutoLock l(&LivermorePolarizedRayleighModelMutex);
454 if(nullptr == dataCS[Z]) { ReadData(Z); }
455 l.unlock();
456 }
457