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G4UrbanAdjointMscModel.hh
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27 // -------------------------------------------------------------------
28 //
29 //
30 // GEANT4 Class header file
31 //
32 //
33 // File name: G4UrbanAdjointMscModel
34 //
35 // Author: Laszlo Urban
36 //
37 // Creation date: 19.02.2013
38 //
39 // Created from G4UrbanAdjointMscModel96
40 //
41 // New parametrization for theta0
42 // Correction for very small step length
43 //
44 // Class Description:
45 //
46 // Implementation of the model of multiple scattering based on
47 // H.W.Lewis Phys Rev 78 (1950) 526 and L.Urban model
48 
49 // -------------------------------------------------------------------
50 //
51 
52 #ifndef G4UrbanAdjointMscModel_h
53 #define G4UrbanAdjointMscModel_h 1
54 
55 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
56 
57 #include <CLHEP/Units/SystemOfUnits.h>
58 
59 #include "G4VMscModel.hh"
60 #include "G4MscStepLimitType.hh"
61 #include "G4Log.hh"
62 #include "G4Exp.hh"
63 #include "G4Electron.hh"
64 
65 
66 class G4ParticleChangeForMSC;
67 class G4SafetyHelper;
68 class G4LossTableManager;
69 
70 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
71 
72 class G4UrbanAdjointMscModel : public G4VMscModel
73 {
74 
75 public:
76 
77  explicit G4UrbanAdjointMscModel(const G4String& nam = "UrbanMsc");
78 
79  virtual ~G4UrbanAdjointMscModel();
80 
81  virtual void Initialise(const G4ParticleDefinition*,
82  const G4DataVector&) override;
83 
84  virtual void StartTracking(G4Track*) override;
85 
86  virtual G4double
87  ComputeCrossSectionPerAtom(const G4ParticleDefinition* particle,
88  G4double KineticEnergy,
89  G4double AtomicNumber,
90  G4double AtomicWeight=0.,
91  G4double cut =0.,
92  G4double emax=DBL_MAX) override;
93 
94  virtual G4ThreeVector& SampleScattering(const G4ThreeVector&,
95  G4double safety) override;
96 
97  virtual G4double
98  ComputeTruePathLengthLimit(const G4Track& track,
99  G4double& currentMinimalStep) override;
100 
101  virtual G4double ComputeGeomPathLength(G4double truePathLength) override;
102 
103  virtual G4double ComputeTrueStepLength(G4double geomStepLength) override;
104 
105  G4double ComputeTheta0(G4double truePathLength, G4double KineticEnergy);
106 
107  inline void SetNewDisplacementFlag(G4bool);
108 
109 private:
110 
111  G4double SampleCosineTheta(G4double trueStepLength, G4double KineticEnergy);
112 
113  void SampleDisplacement(G4double sinTheta, G4double phi);
114 
115  void SampleDisplacementNew(G4double sinTheta, G4double phi);
116 
117  inline void SetParticle(const G4ParticleDefinition*);
118 
119  inline void UpdateCache();
120 
121  inline G4double Randomizetlimit();
122 
123  inline G4double SimpleScattering(G4double xmeanth, G4double x2meanth);
124 
125  // hide assignment operator
126  G4UrbanAdjointMscModel & operator=(const G4UrbanAdjointMscModel &right) = delete;
127  G4UrbanAdjointMscModel(const G4UrbanAdjointMscModel&) = delete;
128 
129  CLHEP::HepRandomEngine* rndmEngineMod;
130 
131  const G4ParticleDefinition* particle;
132  const G4ParticleDefinition* positron;
133  G4ParticleChangeForMSC* fParticleChange;
134 
135  const G4MaterialCutsCouple* couple;
136  G4LossTableManager* theManager;
137 
138  G4double mass;
139  G4double charge,ChargeSquare;
140  G4double masslimite,lambdalimit,fr;
141 
142  G4double taubig;
143  G4double tausmall;
144  G4double taulim;
145  G4double currentTau;
146  G4double tlimit;
147  G4double tlimitmin;
148  G4double tlimitminfix,tlimitminfix2;
149  G4double tgeom;
150 
151  G4double geombig;
152  G4double geommin;
153  G4double geomlimit;
154  G4double skindepth;
155  G4double smallstep;
156 
157  G4double presafety;
158 
159  G4double lambda0;
160  G4double lambdaeff;
161  G4double tPathLength;
162  G4double zPathLength;
163  G4double par1,par2,par3;
164 
165  G4double stepmin;
166 
167  G4double currentKinEnergy;
168  G4double currentRange;
169  G4double rangeinit;
170  G4double currentRadLength;
171 
172  G4int currentMaterialIndex;
173 
174  G4double Zold;
175  G4double Zeff,Z2,Z23,lnZ;
176  G4double coeffth1,coeffth2;
177  G4double coeffc1,coeffc2,coeffc3,coeffc4;
178 
179  G4bool firstStep;
180  G4bool insideskin;
181 
182  G4bool latDisplasmentbackup ;
183  G4bool displacementFlag;
184 
185  G4double rangecut;
186  G4double drr,finalr;
187 
188 };
189 
190 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
191 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
192 
193 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
194 
195 inline void G4UrbanAdjointMscModel::SetNewDisplacementFlag(G4bool val)
196 {
197  displacementFlag = val;
198 }
199 
200 inline
201 void G4UrbanAdjointMscModel::SetParticle(const G4ParticleDefinition* p)
202 { const G4ParticleDefinition* p1 =p;
203 
204  if (p->GetParticleName() =="adj_e-") p1= G4Electron::Electron();
205 
206  if (p1 != particle) {
207  particle = p1;
208  mass = p1->GetPDGMass();
209  charge = p1->GetPDGCharge()/CLHEP::eplus;
210  ChargeSquare = charge*charge;
211  }
212 }
213 
214 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
215 
216 inline G4double G4UrbanAdjointMscModel::Randomizetlimit()
217 {
218  G4double temptlimit = tlimit;
219  if(tlimit > tlimitmin)
220  {
221  G4double delta = tlimit-tlimitmin;
222  do {
223  temptlimit = G4RandGauss::shoot(rndmEngineMod,tlimit,0.1*delta);
224  // Loop checking, 10-Apr-2016, Laszlo Urban
225  } while ((temptlimit < tlimit-delta) ||
226  (temptlimit > tlimit+delta));
227  }
228  else { temptlimit = tlimitmin; }
229 
230  return temptlimit;
231 }
232 
233 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
234 
235 inline void G4UrbanAdjointMscModel::UpdateCache()
236 {
237  lnZ = G4Log(Zeff);
238  // correction in theta0 formula
239  G4double w = G4Exp(lnZ/6.);
240  G4double facz = 0.990395+w*(-0.168386+w*0.093286) ;
241  coeffth1 = facz*(1. - 8.7780e-2/Zeff);
242  coeffth2 = facz*(4.0780e-2 + 1.7315e-4*Zeff);
243 
244  // tail parameters
245  G4double Z13 = w*w;
246  coeffc1 = 2.3785 - Z13*(4.1981e-1 - Z13*6.3100e-2);
247  coeffc2 = 4.7526e-1 + Z13*(1.7694 - Z13*3.3885e-1);
248  coeffc3 = 2.3683e-1 - Z13*(1.8111 - Z13*3.2774e-1);
249  coeffc4 = 1.7888e-2 + Z13*(1.9659e-2 - Z13*2.6664e-3);
250 
251  Z2 = Zeff*Zeff;
252  Z23 = Z13*Z13;
253 
254  Zold = Zeff;
255 }
256 
257 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
258 
259 inline
260 G4double G4UrbanAdjointMscModel::SimpleScattering(G4double xmeanth, G4double x2meanth)
261 {
262  // 'large angle scattering'
263  // 2 model functions with correct xmean and x2mean
264  G4double a = (2.*xmeanth+9.*x2meanth-3.)/(2.*xmeanth-3.*x2meanth+1.);
265  G4double prob = (a+2.)*xmeanth/a;
266 
267  // sampling
268  G4double cth = 1.;
269  if(rndmEngineMod->flat() < prob) {
270  cth = -1.+2.*G4Exp(G4Log(rndmEngineMod->flat())/(a+1.));
271  } else {
272  cth = -1.+2.*rndmEngineMod->flat();
273  }
274  return cth;
275 }
276 
277 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
278 
279 
280 #endif
281