Gabriele Cosmo
137 lines
5.9 KiB
C++
137 lines
5.9 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// //
|
|
// File: G4AlphaDecay.cc //
|
|
// Author: D.H. Wright (SLAC) //
|
|
// Date: 20 October 2014 //
|
|
// //
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#include "G4AlphaDecay.hh"
|
|
#include "G4IonTable.hh"
|
|
#include "Randomize.hh"
|
|
#include "G4ThreeVector.hh"
|
|
#include "G4DynamicParticle.hh"
|
|
#include "G4DecayProducts.hh"
|
|
#include "G4PhysicalConstants.hh"
|
|
#include "G4SystemOfUnits.hh"
|
|
#include <iostream>
|
|
#include <iomanip>
|
|
|
|
G4AlphaDecay::G4AlphaDecay(const G4ParticleDefinition* theParentNucleus,
|
|
const G4double& branch, const G4double& Qvalue,
|
|
const G4double& excitationE)
|
|
: G4NuclearDecay("alpha decay", Alpha, excitationE), transitionQ(Qvalue)
|
|
{
|
|
SetParent(theParentNucleus); // Store name of parent nucleus, delete G4MT_parent
|
|
SetBR(branch);
|
|
|
|
SetNumberOfDaughters(2);
|
|
G4IonTable* theIonTable =
|
|
(G4IonTable*)(G4ParticleTable::GetParticleTable()->GetIonTable());
|
|
G4int daughterZ = theParentNucleus->GetAtomicNumber() - 2;
|
|
G4int daughterA = theParentNucleus->GetAtomicMass() - 4;
|
|
SetDaughter(0, theIonTable->GetIon(daughterZ, daughterA, excitationE) );
|
|
SetDaughter(1, "alpha");
|
|
}
|
|
|
|
|
|
G4AlphaDecay::~G4AlphaDecay()
|
|
{}
|
|
|
|
|
|
G4DecayProducts* G4AlphaDecay::DecayIt(G4double)
|
|
{
|
|
// Fill G4MT_parent with theParentNucleus (stored by SetParent in ctor)
|
|
CheckAndFillParent();
|
|
|
|
// Fill G4MT_daughters with alpha and residual nucleus (stored by SetDaughter)
|
|
CheckAndFillDaughters();
|
|
|
|
G4double alphaMass = G4MT_daughters[1]->GetPDGMass();
|
|
// Excitation energy included in PDG mass
|
|
G4double nucleusMass = G4MT_daughters[0]->GetPDGMass();
|
|
|
|
// Q value was calculated from atomic masses.
|
|
// Use it to get correct alpha energy.
|
|
G4double cmMomentum = std::sqrt(transitionQ*(transitionQ + 2.*alphaMass)*
|
|
(transitionQ + 2.*nucleusMass)*
|
|
(transitionQ + 2.*alphaMass + 2.*nucleusMass) )/
|
|
(transitionQ + alphaMass + nucleusMass)/2.;
|
|
|
|
// Set up final state
|
|
// parentParticle is set at rest here because boost with correct momentum
|
|
// is done later
|
|
G4DynamicParticle parentParticle(G4MT_parent, G4ThreeVector(0,0,0), 0.0);
|
|
G4DecayProducts* products = new G4DecayProducts(parentParticle);
|
|
|
|
G4double costheta = 2.*G4UniformRand()-1.0;
|
|
G4double sintheta = std::sqrt(1.0 - costheta*costheta);
|
|
G4double phi = twopi*G4UniformRand()*rad;
|
|
G4ThreeVector direction(sintheta*std::cos(phi),sintheta*std::sin(phi),
|
|
costheta);
|
|
|
|
G4double KE = std::sqrt(cmMomentum*cmMomentum + alphaMass*alphaMass)
|
|
- alphaMass;
|
|
G4DynamicParticle* daughterparticle =
|
|
new G4DynamicParticle(G4MT_daughters[1], direction, KE, alphaMass);
|
|
products->PushProducts(daughterparticle);
|
|
|
|
KE = std::sqrt(cmMomentum*cmMomentum + nucleusMass*nucleusMass) - nucleusMass;
|
|
daughterparticle =
|
|
new G4DynamicParticle(G4MT_daughters[0], -1.0*direction, KE, nucleusMass);
|
|
products->PushProducts(daughterparticle);
|
|
|
|
// Energy conservation check
|
|
// For alpha decays, do final energy check against reaction Q value
|
|
// which is well-measured using atomic mass differences. Nuclear masses
|
|
// should not be used since they are not usually directly measured and we
|
|
// always decay atoms and not fully stripped nuclei.
|
|
/*
|
|
G4int nProd = products->entries();
|
|
G4DynamicParticle* temp = 0;
|
|
G4double Esum = 0.0;
|
|
for (G4int i = 0; i < nProd; i++) {
|
|
temp = products->operator[](i);
|
|
Esum += temp->GetKineticEnergy();
|
|
}
|
|
G4double eCons = (transitionQ - Esum)/keV;
|
|
if (eCons > 1.e-07) G4cout << " Alpha decay check: Ediff (keV) = " << eCons << G4endl;
|
|
*/
|
|
return products;
|
|
}
|
|
|
|
|
|
void G4AlphaDecay::DumpNuclearInfo()
|
|
{
|
|
G4cout << " G4AlphaDecay for parent nucleus " << GetParentName() << G4endl;
|
|
G4cout << " decays to " << GetDaughterName(0) << " + " << GetDaughterName(1)
|
|
<< " with branching ratio " << GetBR() << "% and Q value "
|
|
<< transitionQ << G4endl;
|
|
}
|
|
|