G4PolarizedComptonCrossSection Class Reference

#include <G4PolarizedComptonCrossSection.hh>

Inheritance diagram for G4PolarizedComptonCrossSection:

G4VPolarizedCrossSection

Public Member Functions

 G4PolarizedComptonCrossSection ()
virtual ~G4PolarizedComptonCrossSection ()
virtual void Initialize (G4double eps, G4double X, G4double phi, const G4StokesVector &p0, const G4StokesVector &p1, G4int flag=0)
G4double XSection (const G4StokesVector &pol2, const G4StokesVector &pol3)
G4double TotalXSection (G4double xmin, G4double xmax, G4double y, const G4StokesVector &pol0, const G4StokesVector &pol1)
G4StokesVector GetPol2 ()
G4StokesVector GetPol3 ()

Detailed Description

Definition at line 57 of file G4PolarizedComptonCrossSection.hh.

Constructor & Destructor Documentation

G4PolarizedComptonCrossSection::G4PolarizedComptonCrossSection (  ) 

Definition at line 51 of file G4PolarizedComptonCrossSection.cc.

References G4INCL::Math::pi, G4VPolarizedCrossSection::SetYmin(), and sqr().

00052   : gammaPol2(false), electronPol3(false)
00053 {
00054   SetYmin(0.);
00055 
00056   //  G4cout<<"G4PolarizedComptonCrossSection() init\n";
00057 
00058   re2 = classic_electr_radius * classic_electr_radius * sqr(4*pi/hbarc);
00059   //  G4double unit_conversion = hbarc_squared ;
00060   //  G4cout<<" (keV)^2* m^2 ="<<unit_conversion<<"\n";
00061   phi0 = 0.; polXS = 0.; unpXS = 0.;
00062   phi2 = G4ThreeVector(0., 0., 0.);
00063   phi3 = G4ThreeVector(0., 0., 0.);
00064   polxx = polyy = polzz = polxz = polzx = polyz = polzy = polxy = polyx = 0.;
00065   diffXSFactor = 1.;
00066   totalXSFactor = 1.;
00067 }

G4PolarizedComptonCrossSection::~G4PolarizedComptonCrossSection (  )  [virtual]

Definition at line 70 of file G4PolarizedComptonCrossSection.cc.

00071 {}

Member Function Documentation

G4StokesVector G4PolarizedComptonCrossSection::GetPol2 (  )  [virtual]

Reimplemented from G4VPolarizedCrossSection.

Definition at line 214 of file G4PolarizedComptonCrossSection.cc.

Referenced by G4PolarizedComptonModel::SampleSecondaries().

00215 {
00216   // Note, mean polarization can not contain correlation 
00217   // effects.
00218   return 1./phi0 * phi2;
00219 }

G4StokesVector G4PolarizedComptonCrossSection::GetPol3 (  )  [virtual]

Reimplemented from G4VPolarizedCrossSection.

Definition at line 223 of file G4PolarizedComptonCrossSection.cc.

Referenced by G4PolarizedComptonModel::SampleSecondaries().

00224 {
00225   // Note, mean polarization can not contain correlation 
00226   // effects.
00227   return 1./phi0 * phi3;
00228 }

void G4PolarizedComptonCrossSection::Initialize ( G4double  eps,
G4double  X,
G4double  phi,
const G4StokesVector &  p0,
const G4StokesVector &  p1,
G4int  flag = 0 
) [virtual]

Reimplemented from G4VPolarizedCrossSection.

Definition at line 74 of file G4PolarizedComptonCrossSection.cc.

References sqr().

Referenced by G4PolarizedComptonModel::SampleSecondaries().

00078 {
00079   G4double cosT = 1. - (1./eps - 1.)/X;
00080   if(cosT > 1.+1.e-8)  cosT = 1.;
00081   if(cosT < -1.-1.e-8) cosT = -1.;
00082   G4double cosT2 = cosT*cosT;
00083   G4double cosT3 = cosT2*cosT;
00084   G4double sinT2 = 1. - cosT2;
00085   if(sinT2 > 1. + 1.e-8) sinT2 = 1.;
00086   if(sinT2 < 0.)     sinT2 = 0.;
00087   G4double sinT = std::sqrt(sinT2);
00088   G4double cos2T = 2.*cosT2 - 1.;
00089   G4double sin2T = 2.*sinT*cosT;
00090   G4double eps2 = sqr(eps);
00091   DefineCoefficients(pol0,pol1);
00092   diffXSFactor = re2/(4.*X);
00093 
00094   // unpolarized Cross Section
00095   unpXS = (eps2 + 1. - eps*sinT2)/(2.*eps);
00096   // initial polarization dependence
00097   polXS = -sinT2*pol0.x() + (1. - eps)*sinT*polzx + ((eps2 - 1.)/eps)*cosT*polzz;
00098   polXS *= 0.5;
00099 
00100   phi0 = unpXS + polXS;
00101 
00102   if (flag == 2 ){
00103   // polarization of outgoing photon
00104   G4double PHI21 = -sinT2 + 0.5*(cos2T + 3.)*pol0.x() - ((1. - eps)/eps)*sinT*polzx;
00105   PHI21 *= 0.5;
00106   G4double PHI22 = cosT*pol0.y() + ((1. - eps)/(2.*eps))*sinT*polzy;
00107   G4double PHI23 = ((eps2 + 1.)/eps)*cosT*pol0.z() - ((1. - eps)/eps)*(eps*cosT2 + 1.)*pol1.z();
00108   PHI23 += 0.5*(1. - eps)*sin2T*pol1.x();
00109   PHI23 += (eps - 1.)*(-sinT2*polxz + sinT*polyy - 0.5*sin2T*polxx);
00110   PHI23 *= 0.5;
00111   phi2 = G4ThreeVector(PHI21, PHI22, PHI23);
00112 
00113   // polarization of outgoing electron
00114   G4double PHI32 = -sinT2*polxy + ((1. - eps)/eps)*sinT*polyz + 0.5*(cos2T + 3.)*pol1.y();
00115   PHI32 *= 0.5;
00116 
00117   G4double PHI31 = 0., PHI31add = 0., PHI33 = 0., PHI33add = 0.;
00118 
00119   if ((1. - eps) > 1.e-12){
00120     G4double helpVar = std::sqrt(eps2 - 2.*cosT*eps + 1.);
00121 
00122     PHI31 = (1. - eps)*(1. + cosT)*sinT*pol0.z();
00123     PHI31 += (-eps*cosT3 + eps*cosT2 + (eps - 2.)*cosT + eps)*pol1.x();
00124     PHI31 += -(eps*cosT2 - eps*cosT + cosT + 1.)*sinT*pol1.z();
00125     PHI31 /= 2.*helpVar;
00126 
00127     PHI31add = -eps*sqr(1. - cosT)*(1. + cosT)*polxx;
00128     PHI31add += (1. - eps)*sinT2*polyy;
00129     PHI31add += -(-eps2 + cosT*(cosT*eps - eps + 1.)*eps + eps - 1.)*sinT*polxz/eps;
00130     PHI31add /= 2.*helpVar;
00131     
00132     PHI33 = ((1. - eps)/eps)*(-eps*cosT2 + eps*(eps + 1.)*cosT - 1.)*pol0.z();
00133     PHI33 += -(eps*cosT2 + (1. - eps)*eps*cosT + 1.)*sinT*pol1.x();
00134     PHI33 += -(-eps2*cosT3 + eps*(eps2 - eps + 1.)*cosT2 - cosT + eps2)*pol1.z()/eps;
00135     PHI33 /= -2.*helpVar;
00136 
00137     PHI33add = (eps*(eps - cosT - 1.)*cosT + 1.)*sinT*polxx;
00138     PHI33add += -(-eps2 + cosT*eps + eps - 1.)*sinT2*polxz;
00139     PHI33add += (eps - 1.)*(cosT - eps)*sinT*polyy;
00140     PHI33add /= -2.*helpVar;
00141   }else{
00142      PHI31 = -pol1.z() - (X - 1.)*std::sqrt(1. - eps)*pol1.x()/std::sqrt(2.*X);
00143      PHI31add = -(-X*X*pol1.z() - 2.*X*(2.*pol0.z() - pol1.z()) - (4.*pol0.x() + 5.)*pol1.z())*(1. - eps)/(4.*X);
00144      
00145      PHI33 = pol1.x() - (X - 1.)*std::sqrt(1. - eps)*pol1.z()/std::sqrt(2.*X);
00146      PHI33add = -(X*X - 2.*X + 4.*pol0.x() + 5.)*(1. - eps)*pol1.x()/(4.*X);
00147   }
00148   phi3 = G4ThreeVector(PHI31 + PHI31add, PHI32, PHI33 + PHI33add);
00149     
00150   }
00151   unpXS *= diffXSFactor;
00152   polXS *= diffXSFactor;
00153   phi0 *= diffXSFactor;
00154   phi2 *= diffXSFactor;
00155   phi3 *= diffXSFactor;
00156   
00157 }

G4double G4PolarizedComptonCrossSection::TotalXSection ( G4double  xmin,
G4double  xmax,
G4double  y,
const G4StokesVector &  pol0,
const G4StokesVector &  pol1 
) [virtual]

Reimplemented from G4VPolarizedCrossSection.

Definition at line 186 of file G4PolarizedComptonCrossSection.cc.

References G4StokesVector::p3(), G4INCL::Math::pi, sqr(), and G4VPolarizedCrossSection::theZ.

00189 {
00190   
00191   //  G4double k0 = gammaEnergy / electron_mass_c2 ;
00192   G4double k1 = 1 + 2*k0 ;
00193 
00194 //   // pi*re^2
00195 //   G4double re=2.81794e-15; //m
00196 //   G4double barn=1.e-28; //m^2
00197   G4double Z=theZ;
00198 
00199   G4double unit = Z*pi*classic_electr_radius  
00200     * classic_electr_radius ; // *1./barn;
00201 
00202   G4double pre = unit/(sqr(k0)*sqr(1.+2.*k0));
00203 
00204   G4double xs_0 = ((k0 - 2.)*k0  -2.)*sqr(k1)*std::log(k1) + 2.*k0*(k0*(k0 + 1.)*(k0 + 8.) + 2.);               
00205   G4double xs_pol = (k0 + 1.)*sqr(k1)*std::log(k1) - 2.*k0*(5.*sqr(k0) + 4.*k0 + 1.);
00206 
00207   return pre*(xs_0/k0 + pol0.p3()*pol1.z()*xs_pol);
00208 }

G4double G4PolarizedComptonCrossSection::XSection ( const G4StokesVector &  pol2,
const G4StokesVector &  pol3 
) [virtual]

Implements G4VPolarizedCrossSection.

Definition at line 159 of file G4PolarizedComptonCrossSection.cc.

References G4StokesVector::ZERO.

00160 {
00161   gammaPol2    = !(pol2==G4StokesVector::ZERO);
00162   electronPol3 = !(pol3==G4StokesVector::ZERO);
00163 
00164   G4double phi = 0.;
00165   // polarization independent part
00166   phi += phi0;
00167 
00168 
00169   if (gammaPol2) { 
00170     // part depending on the polarization of the final photon  
00171     phi += phi2*pol2;
00172   }
00173 
00174   if (electronPol3) {
00175     // part depending on the polarization of the final electron  
00176     phi += phi3*pol3;
00177   }
00178 
00179   // return cross section.
00180   return phi;
00181 }

The documentation for this class was generated from the following files:
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