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Question How can I set the lifetime for photon evaporation processes in Geant4.10.3.p02? 

Forum: Hadronic Processes
Date: 10 Aug, 2017
From: Michael Mathy <Michael Mathy>

Hello Geant4 Community.

For Geant4.10.1 I have a working program which simulates the photon evaporation of excited nuclear states for a certain lifetime. To do so I create an isotope in the “PrimaryGeneratorAction::GeneratePrimaries” via the command “G4ParticleDefinition* ion = G4IonTable::GetIonTable()->GetIon(Z, A, ExcitationEnergy);”. The lifetime which correspond to the state with State-Energy=“ExcitationEnergy” is then read from “ENSDFSTATE.dat” correctly. I check this using the command “particleGun->GetParticleDefinition()->GetPDGLifeTime()” which gives the correct lifetime. I also checked that the lifetime is actually simulated by looking at the decay time distribution using the “SteppingAction”. If I change the lifetime for an excited state in the “ENSDFSTATE.dat” the lifetime changes in the simulation accordingly. So everything works fine here.

Now I have to change to Geant4.10.3.p02. Unfortunately, for Geant4.10.3.p02 the lifetime read in is not working anymore. The lifetime of the excited state which I get from “particleGun->GetParticleDefinition()->GetPDGLifeTime()” is always set to zero. Also the “SteppingAction” shows that the particle evaporates it’s gamma immediately after creation, even though the states exist in “ENSDFSTATE.dat” and “PhotonEvaporation4.3.2” and “PhotonEvaporation4.3.2/correlated_gamma”. In all three files the lifetime is unequal to zero. Trying to understand how the photon evaporation works in Geant4.10.3.p02 I looked at the extended example “radiactivedecay/rdecay02” using the macro “UserRadDataPb210Test.mac “. In “SteppingAction::UserSteppingAction” I added the commands:

if (aStep->GetPostStepPoint()->GetProcessDefinedStep()->GetProcessName() == "RadioactiveDecay") {

std::cout << " FIND Name: " << aStep->GetTrack()->GetParticleDefinition()->GetParticleName();
std::cout << " LifeTime: " << aStep->GetTrack()->GetParticleDefinition()->GetPDGLifeTime() <<
std::endl;
}

If I then start the simulation with

./rdecay02 UserRadDataPb210Test.mac |grep FIND

I get

Name: Bi210[46.539] LifeTime: 0
Name: Bi210[46.539] LifeTime: 0

which is again wrong. Because in all three files (“ENSDFSTATE.dat”, ”PhotonEvaporation4.3.2” and “PhotonEvaporation4.3.2/correlated_gamma”) the Bi-210 state at 46.539 keV exists and has a non-zero lifetime.

So can someone help me and explain to me how I set a certain lifetime to an excited state in Geant4.10.3.p02? Or how can I use own UserEvapData correctly in Geant4.10.3.p02?

Thank you very much in advanced Michael Mathy

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1 None: Re: How can I set the lifetime for photon evaporation processes in Geant4.10.3.p02?   (michel maire - 10 Aug, 2017)
(_ Idea: Re: How can I set the lifetime for photon evaporation processes in Geant4.10.3.p02?   (Michael Mathy - 11 Aug, 2017)
(_ Ok: Re: How can I set the lifetime for photon evaporation processes in Geant4.10.3.p02?   (Michael Mathy - 11 Aug, 2017)
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