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Muon Decay Channel file

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This commit is contained in:
paraiso
2006-03-15 10:37:11 +00:00
parent 9e34d2e943
commit 441cec0b4e
2 changed files with 210 additions and 191 deletions
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119
geant4/LEMuSR/G4Modified/G4MuonDecayChannel.cc
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@ -21,8 +21,8 @@
// ********************************************************************
//
//
// $Id: G4MuonDecayChannel.cc,v 1.11 2004/12/10 18:02:04 gcosmo Exp $
// GEANT4 tag $Name: geant4-07-00-cand-05 $
// $Id: G4MuonDecayChannel.cc,v 1.13 2005/06/23 11:02:26 gcosmo Exp $
// GEANT4 tag $Name: geant4-07-01 $
//
//
// ------------------------------------------------------------
@ -32,6 +32,10 @@
// 30 May 1997 H.Kurashige
//
// Fix bug in calcuration of electron energy in DecayIt 28 Feb. 01 H.Kurashige
//2005
// M. Melissas ( melissas AT cppm.in2p3.fr)
// J. Brunner ( brunner AT cppm.in2p3.fr)
// Adding V-A fluxes for neutrinos using a new algortithm :
// ------------------------------------------------------------
#include "G4ParticleDefinition.hh"
@ -41,6 +45,7 @@
#include "Randomize.hh"
#include "G4LorentzVector.hh"
#include "G4LorentzRotation.hh"
#include "G4RotationMatrix.hh"
G4MuonDecayChannel::G4MuonDecayChannel(const G4String& theParentName,
@ -86,9 +91,9 @@ G4MuonDecayChannel::~G4MuonDecayChannel()
G4DecayProducts *G4MuonDecayChannel::DecayIt(G4double)
{
// this version neglects muon polarization
// this version neglects muon polarization,and electron mass
// assumes the pure V-A coupling
// gives incorrect energy spectrum for neutrinos
// the Neutrinos are correctly V-A.
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) G4cout << "G4MuonDecayChannel::DecayIt ";
#endif
@ -116,61 +121,75 @@ G4DecayProducts *G4MuonDecayChannel::DecayIt(G4double)
// calculate daughter momentum
G4double daughtermomentum[3];
G4double energy;
// calcurate electron energy
G4double xmax = (1.0+daughtermass[0]*daughtermass[0]/parentmass/parentmass);
G4double x;
G4double r;
do {
do {
r = G4UniformRand();
x = xmax*G4UniformRand();
} while (r > (3.0 - 2.0*x)*x*x);
energy = x*parentmass/2.0 - daughtermass[0];
} while (energy <0.0);
//create daughter G4DynamicParticle
// daughter 0 (electron)
daughtermomentum[0] = std::sqrt(energy*energy + 2.0*energy* daughtermass[0]);
G4double costheta, sintheta, phi, sinphi, cosphi;
costheta = 2.*G4UniformRand()-1.0;
sintheta = std::sqrt((1.0-costheta)*(1.0+costheta));
phi = twopi*G4UniformRand()*rad;
sinphi = std::sin(phi);
cosphi = std::cos(phi);
G4ThreeVector direction0(sintheta*cosphi,sintheta*sinphi,costheta);
G4DynamicParticle * daughterparticle
= new G4DynamicParticle( daughters[0], direction0*daughtermomentum[0]);
G4double Ee,Ene;
G4double gam;
G4double EMax=parentmass/2-daughtermass[0];
//Generating Random Energy
do {
Ee=G4UniformRand();
do{
x=xmax*G4UniformRand();
gam=G4UniformRand();
}while (gam >x*(1.-x));
Ene=x;
} while ( Ene < (1.-Ee));
G4double Enm=(2.-Ee-Ene);
//initialisation of rotation parameters
G4double costheta,sintheta,rphi,rtheta,rpsi;
costheta= 1.-2./Ee-2./Ene+2./Ene/Ee;
sintheta=sqrt(1.-costheta*costheta);
rphi=twopi*G4UniformRand()*rad;
rtheta=(acos(2.*G4UniformRand()-1.));
rpsi=twopi*G4UniformRand()*rad;
G4RotationMatrix *rot= new G4RotationMatrix();
rot->set(rphi,rtheta,rpsi);
//electron 0
daughtermomentum[0]=sqrt(Ee*Ee*EMax*EMax+2.0*Ee*EMax * daughtermass[0]);
G4ThreeVector *direction0 =new G4ThreeVector(0.0,0.0,1.0);
*direction0 *= *rot;
G4DynamicParticle * daughterparticle = new G4DynamicParticle ( daughters[0], *direction0 * daughtermomentum[0]);
products->PushProducts(daughterparticle);
// daughter 1 ,2 (nutrinos)
// create neutrinos in the C.M frame of two neutrinos
G4double energy2 = parentmass*(1.0 - x/2.0);
G4double vmass = std::sqrt((energy2-daughtermomentum[0])*(energy2+daughtermomentum[0]));
G4double beta = -1.0*daughtermomentum[0]/energy2;
G4double costhetan = 2.*G4UniformRand()-1.0;
G4double sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan));
G4double phin = twopi*G4UniformRand()*rad;
G4double sinphin = std::sin(phin);
G4double cosphin = std::cos(phin);
//electronic neutrino 1
G4ThreeVector direction1(sinthetan*cosphin,sinthetan*sinphin,costhetan);
G4DynamicParticle * daughterparticle1
= new G4DynamicParticle( daughters[1], direction1*(vmass/2.));
G4DynamicParticle * daughterparticle2
= new G4DynamicParticle( daughters[2], direction1*(-1.0*vmass/2.));
daughtermomentum[1]=sqrt(Ene*Ene*EMax*EMax+2.0*Ene*EMax * daughtermass[1]);
G4ThreeVector *direction1 =new G4ThreeVector(sintheta,0.0,costheta);
// boost to the muon rest frame
G4LorentzVector p4;
p4 = daughterparticle1->Get4Momentum();
p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
daughterparticle1->Set4Momentum(p4);
p4 = daughterparticle2->Get4Momentum();
p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
daughterparticle2->Set4Momentum(p4);
*direction1 *= *rot;
G4DynamicParticle * daughterparticle1 = new G4DynamicParticle ( daughters[1], *direction1 * daughtermomentum[1]);
products->PushProducts(daughterparticle1);
//muonnic neutrino 2
daughtermomentum[2]=sqrt(Enm*Enm*EMax*EMax +2.0*Enm*EMax*daughtermass[2]);
G4ThreeVector *direction2 =new G4ThreeVector(-Ene/Enm*sintheta,0,-Ee/Enm-Ene/Enm*costheta);
*direction2 *= *rot;
G4DynamicParticle * daughterparticle2 = new G4DynamicParticle ( daughters[2],
*direction2 * daughtermomentum[2]);
products->PushProducts(daughterparticle2);
daughtermomentum[1] = daughterparticle1->GetTotalMomentum();
daughtermomentum[2] = daughterparticle2->GetTotalMomentum();
// output message
#ifdef G4VERBOSE

2
geant4/LEMuSR/G4Modified/G4MuonDecayChannel.hh
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@ -22,7 +22,7 @@
//
//
// $Id: G4MuonDecayChannel.hh,v 1.5 2001/07/11 10:01:56 gunter Exp $
// GEANT4 tag $Name: geant4-07-00-cand-01 $
// GEANT4 tag $Name: geant4-07-01 $
//
//
// ------------------------------------------------------------