Only simulate beta, IC or Auger spectrum from a radioactive source

Particles, Track, Event, Run and Biasing
1

_Geant4 Version: 11.3.0
_Operating System: macOS
_Compiler/Version: Clang 19.1.7
_CMake Version: 3.31.6

Hi!

I want to retrieve the emitted energy from a radionuclide using Geant4 simulation. To do this, I placed my radioactive source at the center of an ‘infinite’ sphere, ensuring all emitted energy is deposited into the water medium. However, for Tb-161, I didn’t retrieve the total emitted energy: I obtained 224.08 keV in the simulation compared to 238.84 keV in the ICRP 07 data (It works for Lu-177).

Is it possible to simulate the beta, IC, Auger, X-ray or gamma spectrum individually within Geant4 directly from G4RadioactiveDecayPhysics?

2

In a TrackingAction’s PreUserTrackingAction you can use aTrack()->GetCreatorProcess()->GetProcessName() and check if it is radioactive decay, and then filter by particle type.

Also make sure that your PhysicsList is configured correctly, the radioactivedecay extended examples might be helpful.

1 Like
3

Thanks for your answer!

So I set up my PreUserTrackingAction to look at Auger and IC electrons as follow:

void TrackingAction::PreUserTrackingAction(const G4Track* aTrack )
{

if (aTrack->GetParentID() == 2) {
FILE *myFile;
myFile = fopen (“spectrum.txt”,“a”);
fprintf (myFile, “%s %e %s \n”,
aTrack->GetDefinition()->GetParticleName().c_str(),
aTrack->GetKineticEnergy(),
aTrack->GetCreatorProcess()->GetProcessName().c_str()
);
fclose (myFile);
}

I obtain for 1 disintegration:

e- 3.403008e-03 RadioactiveDecay
gamma 4.608000e-02 RadioactiveDecay
gamma 6.481501e-03 RadioactiveDecay
e- 1.122766e-03 RadioactiveDecay
e- 3.974598e-14 RadioactiveDecay
e- 1.399626e-04 RadioactiveDecay
e- 3.676909e-05 RadioactiveDecay
Dy161[74.567] 1.164153e-08 RadioactiveDecay

I want to check yields and contributions of Auger and IC, I can filter by particle type but if I want to separate Auger and IC electrons, do I also have to filter by energy ? or maybe is possible to know from which process the particle is emitted ?

4

The G4RadioactiveDecay class has a SetICM(G4bool) function, so you can turn Internal Conversion off and see what sort of effect it has.

1 Like
5

From what I understand, setICM is deprecated (or only use in PhotonEvaporation) and I have to use G4DeexPrecoParameters::SetInternalConversionFlag(G4bool) function. I’m trying to do this now.

Another question is: Do the radioactive decay process is included in the physics list (dna_opt2, std_opt4, etc…) ?