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00054 #ifndef G4UrbanMscModel92_h
00055 #define G4UrbanMscModel92_h 1
00056
00057
00058
00059 #include <CLHEP/Units/SystemOfUnits.h>
00060
00061 #include "G4VMscModel.hh"
00062 #include "G4MscStepLimitType.hh"
00063
00064 class G4ParticleChangeForMSC;
00065 class G4SafetyHelper;
00066 class G4LossTableManager;
00067
00068
00069
00070 class G4UrbanMscModel92 : public G4VMscModel
00071 {
00072
00073 public:
00074
00075 G4UrbanMscModel92(const G4String& nam = "UrbanMsc92");
00076
00077 virtual ~G4UrbanMscModel92();
00078
00079 void Initialise(const G4ParticleDefinition*, const G4DataVector&);
00080
00081 void StartTracking(G4Track*);
00082
00083 G4double ComputeCrossSectionPerAtom(const G4ParticleDefinition* particle,
00084 G4double KineticEnergy,
00085 G4double AtomicNumber,
00086 G4double AtomicWeight=0.,
00087 G4double cut =0.,
00088 G4double emax=DBL_MAX);
00089
00090 G4ThreeVector& SampleScattering(const G4ThreeVector&, G4double safety);
00091
00092 G4double ComputeTruePathLengthLimit(const G4Track& track,
00093 G4double& currentMinimalStep);
00094
00095 G4double ComputeGeomPathLength(G4double truePathLength);
00096
00097 G4double ComputeTrueStepLength(G4double geomStepLength);
00098
00099 G4double ComputeTheta0(G4double truePathLength,
00100 G4double KineticEnergy);
00101
00102 private:
00103
00104 G4double SimpleScattering(G4double xmeanth, G4double x2meanth);
00105
00106 G4double SampleCosineTheta(G4double trueStepLength, G4double KineticEnergy);
00107
00108 G4double SampleDisplacement();
00109
00110 G4double LatCorrelation();
00111
00112 inline void SetParticle(const G4ParticleDefinition*);
00113
00114 inline void UpdateCache();
00115
00116
00117 G4UrbanMscModel92 & operator=(const G4UrbanMscModel92 &right);
00118 G4UrbanMscModel92(const G4UrbanMscModel92&);
00119
00120 const G4ParticleDefinition* particle;
00121 G4ParticleChangeForMSC* fParticleChange;
00122
00123 const G4MaterialCutsCouple* couple;
00124 G4LossTableManager* theManager;
00125
00126 G4double mass;
00127 G4double charge,ChargeSquare;
00128 G4double masslimite,lambdalimit,fr;
00129
00130 G4double taubig;
00131 G4double tausmall;
00132 G4double taulim;
00133 G4double currentTau;
00134 G4double tlimit;
00135 G4double tlimitmin;
00136 G4double tlimitminfix;
00137 G4double tgeom;
00138
00139 G4double geombig;
00140 G4double geommin;
00141 G4double geomlimit;
00142 G4double skindepth;
00143 G4double smallstep;
00144
00145 G4double presafety;
00146
00147 G4double lambda0;
00148 G4double lambdaeff;
00149 G4double tPathLength;
00150 G4double zPathLength;
00151 G4double par1,par2,par3;
00152
00153 G4double stepmin;
00154
00155 G4double currentKinEnergy;
00156 G4double currentRange;
00157 G4double rangeinit;
00158 G4double currentRadLength;
00159
00160 G4double theta0max,rellossmax;
00161 G4double third;
00162
00163 G4int currentMaterialIndex;
00164
00165 G4double y;
00166 G4double Zold;
00167 G4double Zeff,Z2,Z23,lnZ;
00168 G4double coeffth1,coeffth2;
00169 G4double coeffc1,coeffc2;
00170 G4double scr1ini,scr2ini,scr1,scr2;
00171
00172 G4bool firstStep;
00173 G4bool inside;
00174 G4bool insideskin;
00175 };
00176
00177
00178
00179
00180 inline
00181 void G4UrbanMscModel92::SetParticle(const G4ParticleDefinition* p)
00182 {
00183 if (p != particle) {
00184 particle = p;
00185 mass = p->GetPDGMass();
00186 charge = p->GetPDGCharge()/CLHEP::eplus;
00187 ChargeSquare = charge*charge;
00188 }
00189 }
00190
00191
00192
00193 inline
00194 void G4UrbanMscModel92::UpdateCache()
00195 {
00196 lnZ = std::log(Zeff);
00197 coeffth1 = 0.885+lnZ*(0.104-0.0170*lnZ);
00198 coeffth2 = 0.028+lnZ*(0.012-0.00125*lnZ);
00199 coeffc1 = 2.134-lnZ*(0.1045-0.00602*lnZ);
00200 coeffc2 = 0.001126-lnZ*(0.0001089+0.0000247*lnZ);
00201 Z2 = Zeff*Zeff;
00202 Z23 = std::exp(2.*lnZ/3.);
00203 scr1 = scr1ini*Z23;
00204 scr2 = scr2ini*Z2*ChargeSquare;
00205
00206 Zold = Zeff;
00207 }
00208
00209 #endif
00210