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25 //
26 // Author: Alexei Sytov
27 // Co-author: Gianfranco Paterno (modifications & testing)
28 // On the base of the CRYSTALRAD realization of the Baier-Katkov integral:
29 // A. I. Sytov, V. V. Tikhomirov, and L. Bandiera PRAB 22, 064601 (2019)
30
31 #ifndef G4BaierKatkov_h
32 #define G4BaierKatkov_h 1
33
34 #include "globals.hh"
35 #include <CLHEP/Units/SystemOfUnits.h>
36 #include <vector>
37 #include "G4ThreeVector.hh"
38
39 #include "G4VFastSimulationModel.hh"
40
41 /** \file G4BaierKatkov.hh
42 * \brief Definition of the G4BaierKatkov class
43 * This class is designed for the calculation of radiation probability, radiation point
44 * and the parameters of the photon produced as well as spectrum accumulation using
45 * the Baier-Katkov integral:
46 * V. N. Baier, V. M. Katkov, and V. M. Strakhovenko,
47 * Electromagnetic Processes at High Energies in Oriented Single Crystals
48 * (World Scientific, Singapore, 1998).
49 */
50
51 class G4BaierKatkov
52 {
53 public:
54 // default constructor
55 G4BaierKatkov();
56
57 // destructor
58 ~G4BaierKatkov() = default;
59
60 /**
61 You may call DoRadiation at each step of your trajectory
62 CAUTION: please ensure that your steps are physically small enough for calculation
63 of the radiation type you are interested in
64 CAUTION: do ResetRadIntegral() before the start of a new trajectory
65
66 1) change some model defaults if necessary
67 (SetSinglePhotonRadiationProbabilityLimit,
68 SetNSmallTrajectorySteps, SetSpectrumEnergyRange)
69 2) call DoRadiation at each step of your trajectory
70 3) if DoRadiation returns TRUE, this means that a photon is produced (not added
71 as a secondary yet) and its parameters are calculated.
72 4) You may generate a new photon using GeneratePhoton either with
73 the parameters calculated in DoRadiation or your own parameters.
74 CAUTION: By now GeneratePhoton works only for a FastSim model
75 5) Use GetPhotonEnergyInSpectrum() and GetTotalSpectrum() to return calculated
76 total spectrum (all the photons altogether)
77 Caution: is not normalized on the event number
78 6) Get the charged particle parameters in the radiation point:
79 GetParticleNewTotalEnergy(),
80 GetParticleNewAngleX(), GetParticleNewAngleY(),
81 GetNewGlobalTime(),
82 GetParticleNewCoordinateXYZ()
83 */
84
85 ///get functions
86
87 /// get maximal radiation probability to preserve single photon radiation
88 G4double GetSinglePhotonRadiationProbabilityLimit()
89 {return fSinglePhotonRadiationProbabilityLimit;}
90
91 ///CAUTION! : use the get functions below ONLY AFTER the call of DoRadiation
92 /// and ONLY IF IT RETURNS true
93
94 ///total probability of radiation: needs calculation of DoRadiation first
95 G4double GetTotalRadiationProbability(){return fTotalRadiationProbability;}
96 ///get new parameters of the particle
97 ///(the parameters at the point of radiation emission)
98 ///needs calculation of DoRadiation first
99 G4double GetParticleNewTotalEnergy(){return fNewParticleEnergy;}
100 G4double GetParticleNewAngleX(){return fNewParticleAngleX;}
101 G4double GetParticleNewAngleY(){return fNewParticleAngleY;}
102 G4double GetNewGlobalTime(){return fNewGlobalTime;}
103 const G4ThreeVector& GetParticleNewCoordinateXYZ(){return fNewParticleCoordinateXYZ;}
104
105 ///get photon energies (x-value in spectrum)
106 const std::vector<G4double>& GetPhotonEnergyInSpectrum()
107 {return fPhotonEnergyInSpectrum;}
108
109 ///get fTotalSpectrum after finishing the trajectory part with DoRadiation
110 const std::vector<G4double>& GetTotalSpectrum(){return fTotalSpectrum;}
111
112 ///set functions
113
114 ///set maximal radiation probability to preserve single photon radiation
115 void SetSinglePhotonRadiationProbabilityLimit(G4double wmax)
116 {fSinglePhotonRadiationProbabilityLimit = wmax;}
117
118 ///number of steps in a trajectory small piece before
119 ///the next call of the radiation integral
120 void SetNSmallTrajectorySteps(G4int nSmallTrajectorySteps)
121 {fNSmallTrajectorySteps = nSmallTrajectorySteps;}
122
123 ///reinitialize intermediate integrals fFa, fSs, fSc, fSsx, fSsy, fScx, fScy;
124 ///reset radiation integral internal variables to defaults;
125 ///reset the trajectory and radiation probability along the trajectory
126 void ResetRadIntegral();
127
128 ///setting the number of photons in sampling of Baier-Katkov Integral
129 ///(MC integration by photon energy and angles <=> photon momentum)
130 void SetSamplingPhotonsNumber(G4int nPhotons){fNMCPhotons = nPhotons;}
131
132 ///setting the number of radiation angles 1/gamma, defining the width of
133 ///the angular distribution of photon sampling in the Baier-Katkov Integral
134 void SetRadiationAngleFactor(G4double radiationAngleFactor)
135 {fRadiationAngleFactor = radiationAngleFactor;}
136
137 ///CAUTION, the bins width is logarithmic
138 ///Do not worry if the maximal energy > particle energy.
139 ///This elements of spectrum with non-physical energies
140 ///will not be processed (they will be 0).
141 void SetSpectrumEnergyRange(G4double emin,
142 G4double emax,
143 G4int numberOfBins);
144 /// SetSpectrumEnergyRange also calls ResetRadIntegral()
145
146 void SetMinPhotonEnergy(G4double emin){SetSpectrumEnergyRange(emin,
147 fMaxPhotonEnergy,
148 fNBinsSpectrum);}
149 void SetMaxPhotonEnergy(G4double emax){SetSpectrumEnergyRange(fMinPhotonEnergy,
150 emax,
151 fNBinsSpectrum);}
152 void SetNBinsSpectrum(G4int nbin){SetSpectrumEnergyRange(fMinPhotonEnergy,
153 fMaxPhotonEnergy,
154 nbin);}
155
156 /// Increase the statistic of virtual photons in a certain energy region
157 /// CAUTION! : don't do it before SetSpectrumEnergyRange or SetMinPhotonEnergy
158 void AddStatisticsInPhotonEnergyRegion(G4double emin, G4double emax,
159 G4int timesPhotonStatistics);
160
161 /// Virtual collimator masks the selection of photon angles in fTotalSpectrum
162 /// Virtual collimator doesn't influence on Geant4 simulations.
163 void SetVirtualCollimator(G4double virtualCollimatorAngularDiameter)
164 {fVirtualCollimatorAngularDiameter=virtualCollimatorAngularDiameter;}
165
166 /// add the new elements of the trajectory, calculate radiation in a crystal
167 /// see complete description in G4BaierKatkov::DoRadiation
168 /// calls RadIntegral and all the necessary functions
169 /// sets the parameters of a photon produced (if any)
170 /// using SetPhotonProductionParameters()
171 /// returns true in the case of photon generation, false if not
172 G4bool DoRadiation(G4double etotal, G4double mass,
173 G4double angleX, G4double angleY,
174 G4double angleScatteringX, G4double angleScatteringY,
175 G4double step, G4double globalTime,
176 G4ThreeVector coordinateXYZ,
177 G4bool flagEndTrajectory=false);
178
179 /// generates secondary photon belonging to fastStep with variables
180 /// photon energy, momentum direction, coordinates and global time
181 /// CALCULATED IN DoRadiation => USE IT ONLY AFTER DoRadiation returns true
182 void GeneratePhoton(G4FastStep &fastStep);
183
184 private:
185
186 ///set functions
187
188 ///function setting the photon sampling parameters in the Baier-Katkov integral;
189 ///only the maximal energy is set, while fMinPhotonEnergy is used as a minimal energy;
190 ///the angles set the angular distribution (the tails are infinite)
191 void SetPhotonSamplingParameters(G4double ekin,
192 G4double minPhotonAngleX, G4double maxPhotonAngleX,
193 G4double minPhotonAngleY, G4double maxPhotonAngleY);
194
195 ///main functions:
196
197 ///generation of the photons in sampling of Baier-Katkov Integral
198 ///(MC integration by photon energy and angles <=> by photon momentum)
199 void GeneratePhotonSampling();
200
201 ///Baier-Katkov method: calculation of integral, spectrum, full probability;
202 ///returns the total radiation probability;
203 ///calculates the radiation spectrum on this trajectory piece
204 G4double RadIntegral(G4double etotal, G4double mass,
205 std::vector<G4double> &vectorParticleAnglesX,
206 std::vector<G4double> &vectorParticleAnglesY,
207 std::vector<G4double> &vectorScatteringAnglesX,
208 std::vector<G4double> &vectorScatteringAnglesY,
209 std::vector<G4double> &vectorSteps,
210 G4int imin);
211
212 ///set photon production parameters (returns false if no photon produced)
213 ///accumulates fTotalSpectrum
214 ///CAUTION: it is an accessory function of DoRadiation, do not use it separately
215 G4bool SetPhotonProductionParameters(G4double etotal, G4double mass);
216
217 G4int FindVectorIndex(std::vector<G4double> &myvector, G4double value);
218
219 G4double fTotalRadiationProbability = 0.;
220 G4double fSinglePhotonRadiationProbabilityLimit=0.25;//Maximal radiation
221 //probability to preserve single photon radiation
222
223 //number of steps in a trajectory piece before the next call of the radiation integral
224 G4int fNSmallTrajectorySteps=10000;
225 ///trajectory element No (the first element of the array feeded in RadIntegral)
226 G4int fImin0 = 0;
227 ///Monte Carlo statistics of photon sampling in Baier-Katkov with 1 trajectory
228 G4int fNMCPhotons =150;
229 ///the number of bins in photon spectrum
230 G4int fNBinsSpectrum = 110;
231 G4double fMinPhotonEnergy = 0.1*CLHEP::MeV;//min energy in spectrum output
232 G4double fMaxPhotonEnergy = 1*CLHEP::GeV; //max energy in spectrum output
233 G4double fLogEmaxdEmin = 1.;// = log(fMaxPhotonEnergy/fMinPhotonEnergy),
234 // 1/normalizing coefficient in
235 // 1/E distribution between
236 // fMinPhotonEnergy and fMaxPhotonEnergy
237 // is used only for spectrum output, not for simulations
238 //(we take bremsstrahlung for photon sampling)
239 G4double fLogEdEmin = 1.; // = log(E/fMinPhotonEnergy), the same as fLogEmaxdEmin
240 // but with the particle energy as the maximal limit
241
242 G4double fVirtualCollimatorAngularDiameter=1.;//default, infinite angle
243 std::vector<G4bool> fInsideVirtualCollimator;
244
245 ///data of the phootn energy range with additional statistics
246 std::vector<G4double> fLogAddRangeEmindEmin;//=G4Log(emin/fMinPhotonEnergy)
247 std::vector<G4double> fLogAddRangeEmaxdEmin;//=G4Log(emax/fMinPhotonEnergy)
248 std::vector<G4int> fTimesPhotonStatistics;
249
250 ///number of trajectories
251 //(at each of the Baier-Katkov Integral is calculated for the same photons)
252 G4int fItrajectories = 0;
253
254 G4double fEph0=0; //energy of the photon produced
255 G4ThreeVector PhMomentumDirection; //momentum direction of the photon produced
256
257 ///Radiation integral variables
258 G4double fMeanPhotonAngleX =0.; //average angle of radiated photon direction
259 //in sampling, x-plane
260 G4double fParamPhotonAngleX=1.e-3*CLHEP::rad; //a parameter radiated photon
261 //sampling distribution, x-plane
262 G4double fMeanPhotonAngleY =0.; //average angle of radiated photon direction
263 //in sampling, y-plane
264 G4double fParamPhotonAngleY=1.e-3*CLHEP::rad; //a parameter radiated photon
265 //sampling distribution, y-plane
266 G4double fRadiationAngleFactor = 4.; // number of radiation angles 1/gamma:
267 // more fRadiationAngleFactor =>
268 // higher fParamPhotonAngleX and Y
269
270 ///new particle parameters (the parameters at the point of radiation emission)
271 G4double fNewParticleEnergy=0;
272 G4double fNewParticleAngleX=0;
273 G4double fNewParticleAngleY=0;
274 G4double fNewGlobalTime=0;
275 G4ThreeVector fNewParticleCoordinateXYZ;
276
277 ///sampling of the energy and the angles of a photon emission
278 ///(integration variables, Monte Carlo integration)
279 std::vector<G4double> fPhotonEnergyInIntegral;
280 std::vector<G4double> fPhotonAngleInIntegralX;
281 std::vector<G4double> fPhotonAngleInIntegralY;
282 std::vector<G4double> fPhotonAngleNormCoef;
283 ///spectrum bin index for each photon
284 std::vector<G4double> fIBinsSpectrum;
285 ///the vector of the discrete CDF of the radiation of sampling photons
286 std::vector<G4double> fPhotonProductionCDF;
287
288 ///vectors of the trajectory
289 std::vector<G4double> fParticleAnglesX;
290 std::vector<G4double> fParticleAnglesY;
291 std::vector<G4double> fScatteringAnglesX;
292 std::vector<G4double> fScatteringAnglesY;
293 std::vector<G4double> fSteps;
294 std::vector<G4double> fGlobalTimes;
295 std::vector<G4ThreeVector> fParticleCoordinatesXYZ;
296
297 ///intermediate integrals (different for each photon energy value)!!!
298 std::vector<G4double> fFa;//phase
299 std::vector<G4double> fSs;
300 std::vector<G4double> fSc;
301 std::vector<G4double> fSsx;
302 std::vector<G4double> fSsy;
303 std::vector<G4double> fScx;
304 std::vector<G4double> fScy;
305
306 ///output
307 std::vector<G4double> fPhotonEnergyInSpectrum; //energy values in spectrum
308
309 std::vector<G4int> fNPhotonsPerBin; //number of photons per spectrum bin
310 //(accumulating during total run)
311
312 std::vector<G4double> fSpectrum; //spectrum normalized by the total
313 //radiation probability of one particle at one call of RadIntegral
314
315 std::vector<std::vector<G4double>> fAccumSpectrum; //accumulate Spectrum during
316 //the part of a trajectory
317
318 std::vector<G4double> fAccumTotalSpectrum; //spectrum normalized by the total
319 //radiation probability summed
320 //for all the particles (is not divided
321 //of one particle number fNPhotonsPerBin)
322
323 std::vector<G4double> fTotalSpectrum; //spectrum normalized by
324 //the total radiation probability summed
325 //for all the particles
326 //(is divided by the photon number fNPhotonsPerBin)
327 //multiplied by the number of trajectories
328 //(fItrajectories)
329
330 std::vector<G4double> fImax0; //trajectory element numbers at the end of each
331 //small piece; G4double just for security of some operations
332 ///total radiation probability along this trajectory
333 std::vector<G4double> fTotalRadiationProbabilityAlongTrajectory;
334 };
335
336 #endif
337