Command thresholdForVeryLongDecayTime for radioactive decay

[montarou]

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_Geant4 Version:V11.2.2
_Operating System:Ubuntu 24.04
Compiler/Version:
CMake Version:

No Radioactive decay
Command thresholdForVeryLongDecayTime

Hello,
I’m writing a simple Geant4 program that uses a CO60 source as a particle generator.
The program compiles without errors, but when I run it, I don’t get any secondary particles.
Looking at previous posts, I found that I needed to change the thresholdForVeryLongDecayTime variable from 1 year to a very high value.

As recommended, I wanted to change the value in the GUI using the command
/process/had/rdm/thresholdForVeryLongDecayTime
But apparently this command isn’t among the available options.

I use the Geant4 v11.2.2

Does anyone have any ideas?

[ribon]

Hello,

I guess there is something wrong on your set-up, but I can’t tell you how to fix it.

I confirm that in Geant4 11.2.p02, the command “/process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 year” is properly defined.
For instance, you can run the Geant4 example:
examples/extended/radioactivedecay/rdecay01
using the macro Co60.mac .
If you comment, in this macro, the above line:
#/process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 year
you get quite different results.

Best regards,
Alberto

[bmorgan]

What physics list are you using? The radioactive decay related commands should be available if this process has been added to the relevant particles in the physics list.

[montarou]

I solve my problem…of PhysicsList declaration…
Here after the programs i used.. it can perhaps help some body

first PhysicsList.hh and .cc

#ifndef PHYSICS_HH
#define PHYSICS_HH

#include "G4VModularPhysicsList.hh"
#include "G4EmStandardPhysics.hh"
#include "G4OpticalPhysics.hh"
#include "G4DecayPhysics.hh"
#include "G4RadioactiveDecayPhysics.hh"

class MyPhysicsList : public G4VModularPhysicsList
{
public:
    MyPhysicsList();
    ~MyPhysicsList();
};

#endif
``̀`


``
                               è
#include "physics.hh"

MyPhysicsList::MyPhysicsList()
{
    RegisterPhysics (new G4EmStandardPhysics());
    RegisterPhysics (new G4OpticalPhysics());
    RegisterPhysics (new G4DecayPhysics());
    RegisterPhysics (new G4RadioactiveDecayPhysics());

}

MyPhysicsList::~MyPhysicsList()
{

}

and the generator.cc and .hh

#ifndef GENERATOR_HH
#define GENERATOR_HH

#include "G4VUserPrimaryGeneratorAction.hh"

#include "G4ParticleGun.hh"
#include "G4SystemOfUnits.hh"
#include "G4ParticleTable.hh"
#include "G4Geantino.hh"
#include "G4IonTable.hh"

class MyPrimaryGenerator : public G4VUserPrimaryGeneratorAction
{
public:
    MyPrimaryGenerator();
    ~MyPrimaryGenerator();

    virtual void GeneratePrimaries(G4Event*);

private:
    G4ParticleGun *fParticleGun;
};

#endif

#include "generator.hh"

MyPrimaryGenerator::MyPrimaryGenerator()
{
    fParticleGun = new G4ParticleGun(1);

    G4ParticleTable *particleTable = G4ParticleTable::GetParticleTable();
    G4ParticleDefinition *particle = particleTable->FindParticle("geantino");

    G4ThreeVector pos(0.,0.,0.);
    G4ThreeVector mom(0.,0.,1.);

    fParticleGun->SetParticlePosition(pos);
    fParticleGun->SetParticleMomentumDirection(mom);
    fParticleGun->SetParticleMomentum(0.*GeV);
    fParticleGun->SetParticleDefinition(particle);
}

MyPrimaryGenerator::~MyPrimaryGenerator()
{
    delete fParticleGun;
}

void MyPrimaryGenerator::GeneratePrimaries(G4Event *anEvent)
{
    G4ParticleDefinition *particle = fParticleGun->GetParticleDefinition();

    if(particle == G4Geantino::Geantino())
    {
        G4int Z = 27;
        G4int A = 60;

        G4double charge = 0.*eplus;
        G4double energy = 0.*keV;

        G4ParticleDefinition *ion = G4IonTable::GetIonTable()->GetIon(Z,A,energy);

        fParticleGun -> SetParticleDefinition(ion);
        fParticleGun -> SetParticleCharge(charge);

        //G4cout << "Generation d'un ion "<<"Z ="<< Z<<"A ="<< A<<"energie :"<<energy<<"charge="<<charge<< G4endl;

    }
    fParticleGun->GeneratePrimaryVertex(anEvent);
}

the results.. when set

/process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 years

and for 20 events